Publications by authors named "Kan Wang"

388 Publications

Application of Textile Technology in Tissue Engineering: A review.

Acta Biomater 2021 May 4. Epub 2021 May 4.

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta, GA 30332, USA; H. Milton Stewart School of Industrial and System Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

One of the key elements in tissue engineering is to design and fabricate scaffolds with tissue-like properties. Among various scaffold fabrication methods, textile technology has shown its unique advantages in mimicking human tissues' properties such as hierarchical, anisotropic, and strain-stiffening properties. As essential components in textile technology, textile patterns affect the porosity, architecture, and mechanical properties of textile-based scaffolds. However, the potential of various textile patterns has not been fully explored when fabricating textile-based scaffolds, and the effect of different textile patterns on scaffold properties has not been thoroughly investigated. This review summarizes textile technology development and highlights its application in tissue engineering to facilitate the broader application of textile technology, especially various textile patterns in tissue engineering. The potential of using different textile methods such as weaving, knitting, and braiding to mimic properties of human tissues is discussed, and the effect of process parameters in these methods on fabric properties is summarized. Finally, perspectives on future directions for explorations are presented. STATEMENT OF SIGNIFICANCE: : Recently, biomedical engineers have applied textile technology to fabricate scaffolds for tissue engineering applications. Various textile methods, especially weaving, knitting, and braiding, enables engineers to customize the physical, mechanical, and biological properties of scaffolds. However, most textile-based scaffolds only use simple textile patterns, and the effect of different textile patterns on scaffold properties has not been thoroughly investigated. In this review, we cover for the first time the effect of process parameters in different textile methods on fabric properties, exploring the potential of using different textile methods to mimic properties of human tissues. Previous advances in textile technology are presented, and future directions for explorations are presented, hoping to facilitate new breakthroughs of textile-based tissue engineering.
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http://dx.doi.org/10.1016/j.actbio.2021.04.047DOI Listing
May 2021

Solid-state rigid-rod polymer composite electrolytes with nanocrystalline lithium ion pathways.

Nat Mater 2021 May 3. Epub 2021 May 3.

Department of Chemistry and Macromolecules Innovation Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.

A critical challenge for next-generation lithium-based batteries lies in development of electrolytes that enable thermal safety along with the use of high-energy-density electrodes. We describe molecular ionic composite electrolytes based on an aligned liquid crystalline polymer combined with ionic liquids and concentrated Li salt. This high strength (200 MPa) and non-flammable solid electrolyte possesses outstanding Li conductivity (1 mS cm at 25 °C) and electrochemical stability (5.6 V versus Li|Li) while suppressing dendrite growth and exhibiting low interfacial resistance (32 Ω cm) and overpotentials (≤120 mV at 1 mA cm) during Li symmetric cell cycling. A heterogeneous salt doping process modifies a locally ordered polymer-ion assembly to incorporate an inter-grain network filled with defective LiFSI and LiBF nanocrystals, strongly enhancing Li conduction. This modular material fabrication platform shows promise for safe and high-energy-density energy storage and conversion applications, incorporating the fast transport of ceramic-like conductors with the superior flexibility of polymer electrolytes.
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http://dx.doi.org/10.1038/s41563-021-00995-4DOI Listing
May 2021

Layered-rocksalt intergrown cathode for high-capacity zero-strain battery operation.

Nat Commun 2021 Apr 20;12(1):2348. Epub 2021 Apr 20.

Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.

The dependence on lithium-ion batteries leads to a pressing demand for advanced cathode materials. We demonstrate a new concept of layered-rocksalt intergrown structure that harnesses the combined figures of merit from each phase, including high capacity of layered and rocksalt phases, good kinetics of layered oxide and structural advantage of rocksalt. Based on this concept, lithium nickel ruthenium oxide of a main layered structure (R[Formula: see text]m) with intergrown rocksalt (Fm[Formula: see text]m) is developed, which delivers a high capacity with good rate performance. The interwoven rocksalt structure successfully prevents the anisotropic structural change that is typical for layered oxide, enabling a nearly zero-strain operation upon high-capacity cycling. Furthermore, a design principle is successfully extrapolated and experimentally verified in a series of compositions. Here, we show the success of such layered-rocksalt intergrown structure exemplifies a new battery electrode design concept and opens up a vast space of compositions to develop high-performance intergrown cathode materials.
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http://dx.doi.org/10.1038/s41467-021-22527-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8058087PMC
April 2021

Textile-based sandwich scaffold using wet electrospun yarns for skin tissue engineering.

J Mech Behav Biomed Mater 2021 Apr 8;119:104499. Epub 2021 Apr 8.

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta, GA, USA; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA, USA.

One of the key elements in tissue engineering is to design and fabricate scaffolds with tissue-like properties. However, mimicking the strain-stiffening property of human tissues by using synthetic materials is still a challenge in scaffold fabrication since most synthetic materials exhibit strain-softening behavior. To address this challenge, we propose a textile-based sandwich scaffold to mimic strain-stiffening behavior observed in human tissues. For this purpose, we first fabricate polycaprolactone (PCL) yarns by wet electrospinning. Then, we crochet PCL yarns into a textile fabric. Finally, we fabricate the sandwich scaffold by embedding the textile fabric inside two electrospun mats. The wet electrospun PCL yarns induce cellular alignment and elongation. The textile-based sandwich scaffold exhibits strain-stiffening behavior. By changing process parameters during the yarn fabrication and textile process, we can adjust the maximum stress of the scaffold from 5.40 to 8.83 MPa, the maximum strain from 0.89 to 1.69, and the elastic modulus from 2.9 to 10.31 MPa, all within the ranges of that of human skin. The scaffold is also able to support cell proliferation and infiltration after optimizing the thickness of the outer layers of the sandwich scaffold. This study validates the potential of the textile-based sandwich scaffold to mimic the physical, mechanical, and biological properties of human skin and other tissues.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104499DOI Listing
April 2021

Pathogenic and Virulence Factor Detection on Viable but Non-culturable Methicillin-Resistant .

Front Microbiol 2021 25;12:630053. Epub 2021 Mar 25.

Department of Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China.

Food safety and foodborne infections and diseases have been a leading hotspot in public health, and methicillin-resistant (MRSA) has been recently documented to be an important foodborne pathogen, in addition to its recognition to be a leading clinical pathogen for some decades. Standard identification for MRSA has been commonly performed in both clinical settings and food routine detection; however, most of such so-called "standards," "guidelines," or "gold standards" are incapable of detecting viable but non-culturable (VBNC) cells. In this study, two major types of staphylococcal food poisoning (SFP), staphylococcal enterotoxins A () and staphylococcal enterotoxins B (), as well as the panton-valentine leucocidin () genes, were selected to develop a cross-priming amplification (CPA) method. Limit of detection (LOD) of CPA for , , and was 75, 107.5, and 85 ng/μl, indicating that the analytical sensitivity of CPA is significantly higher than that of conventional PCR. In addition, a rapid VBNC cells detection method, designated as PMA-CPA, was developed and further applied. PMA-CPA showed significant advantages when compared with PCR assays, in terms of rapidity, sensitivity, specificity, and accuracy. Compared with conventional VBNC confirmation methods, the PMA-CPA showed 100% accordance, which had demonstrated that the PMA-CPA assays were capable of detecting different toxins in MRSA in VBNC state. In conclusion, three CPA assays were developed on three important toxins for MRSA, and in combination with PMA, the PMA-CPA assay was capable of detecting virulent gene expression in MRSA in the VBNC state. Also, the above assays were further applied to real samples. As concluded, the PMA-CPA assay developed in this study was capable of detecting MRSA toxins in the VBNC state, representing first time the detection of toxins in the VBNC state.
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http://dx.doi.org/10.3389/fmicb.2021.630053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8027501PMC
March 2021

An improved biolistic delivery and analysis method for evaluation of DNA and CRISPR-Cas delivery efficacy in plant tissue.

Sci Rep 2021 Apr 8;11(1):7695. Epub 2021 Apr 8.

Department of Materials Science and Engineering, Iowa State University, Ames, IA, USA.

Biolistic delivery is widely used for genetic transformation but inconsistency between bombardment samples for transient gene expression analysis often hinders quantitative analyses. We developed a methodology to improve the consistency of biolistic delivery results by using a double-barrel device and a cell counting software. The double-barrel device enables a strategy of incorporating an internal control into each sample, which significantly decreases variance of the results. The cell counting software further reduces errors and increases throughput. The utility of this new platform is demonstrated by optimizing conditions for delivering DNA using the commercial transfection reagent TransIT-2020. In addition, the same approach is applied to test the efficacy of multiple gRNAs for CRISPR-Cas9-mediated gene editing. The novel combination of the bombardment device and analysis method allows simultaneous comparison and optimization of parameters in the biolistic delivery. The platform developed here can be broadly applied to any target samples using biolistics, including animal cells and tissues.
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http://dx.doi.org/10.1038/s41598-021-86549-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8032657PMC
April 2021

Using Wet Electrospun PCL/Gelatin/CNT Yarns to Fabricate Textile-Based Scaffolds for Vascular Tissue Engineering.

ACS Biomater Sci Eng 2021 Apr 6. Epub 2021 Apr 6.

School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Dr NW, Atlanta 30332, Georgia, United States.

Incorporating conductive materials in scaffolds has shown advantages in regulating adhesion, mitigation, and proliferation of electroactive cells for tissue engineering applications. Among various conductive materials, carbon nanotubes (CNTs) have shown great promises in tissue engineering because of their good mechanical properties. However, the broad application of CNTs in tissue engineering is limited by current methods to incorporate CNTs in polymers that require miscible solvents to dissolve CNTs and polymers or CNT surface modification. These methods either limit polymer selections or adversely affect the properties of polymer/CNT composites. Here, we report a novel method to fabricate polymer/CNT composite yarns by electrospinning polycaprolactone/gelatin into a bath of CNT dispersion and extracting electrospun fibers out of the bath. The concentration of CNTs in the bath affects the thermal and mechanical properties and the yarns' degradation behavior. biological test results show that within a limited range of CNT concentrations in the bath, the yarns exhibit good biocompatibility and the ability to guide cell elongation and alignment. We also report the design and fabrication of a vascular scaffold by knitting the yarns into a textile fabric and combining the textile fabric with gelatin. The scaffold has similar mechanical properties to native vessels and supports cell proliferation. This work demonstrates that the wet electrospun polymer/CNT yarns are good candidates for constructing vascular scaffolds and provides a novel method to incorporate CNTs or other functional materials into biopolymers for tissue engineering applications.
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http://dx.doi.org/10.1021/acsbiomaterials.1c00097DOI Listing
April 2021

High-Throughput Cell Trapping in the Dentate Spiral Microfluidic Channel.

Micromachines (Basel) 2021 Mar 9;12(3). Epub 2021 Mar 9.

Engineering Research Center of Optical Instrument and System, the Ministry of Education, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China.

Cell trapping is a very useful technique in a variety of cell-based assays and cellular research fields. It requires a high-throughput, high-efficiency operation to isolate cells of interest and immobilize the captured cells at specific positions. In this study, a dentate spiral microfluidic structure is proposed for cell trapping. The structure consists of a main spiral channel connecting an inlet and an out and a large number of dentate traps on the side of the channel. The density of the traps is high. When a cell comes across an empty trap, the cell suddenly makes a turn and enters the trap. Once the trap captures enough cells, the trap becomes closed and the following cells pass by the trap. The microfluidic structure is optimized based on the investigation of the influence over the flow. In the demonstration, 4T1 mouse breast cancer cells injected into the chip can be efficiently captured and isolated in the different traps. The cell trapping operates at a very high flow rate (40 μL/s) and a high trapping efficiency (>90%) can be achieved. The proposed high-throughput cell-trapping technique can be adopted in the many applications, including rapid microfluidic cell-based assays and isolation of rare circulating tumor cells from a large volume of blood sample.
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http://dx.doi.org/10.3390/mi12030288DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8000121PMC
March 2021

Depth estimation method of surface of micropart in microassembly space based on microscopic vision tomographic scanning images.

J Microsc 2021 Apr 1. Epub 2021 Apr 1.

Precision and Intelligence Laboratory, Department of Measurement and Control Technology and Instrument, Chongqing University, Chongqing, China.

Three-dimensional (3D) morphology of microparts has an important influence on performance of microassembly system that mainly assembles microparts in millimetre and micron scale. Because 3D morphology of microparts cannot be accurately obtained by conventional microscopic vision system, a depth estimation method of surface of micropart in microassembly space based on microscopic vision tomographic scanning (MVTS) images is proposed in this paper. The proposed method uses the positions of pixels with the largest focus values in MVTS image to construct the isodepth contours of surface of micropart and obtains the depth values of micropart's surface at the positions of MVTS by assigning depth values to corresponding isodepth contours. The MVTS images are obtained by MVTS and pixels with the largest focus values in MVTS image are obtained by focus measurement of MVTS images of micropart in microassembly space. On these bases, 3D spatial interpolation method is applied to map depth value of space between adjacent isodepth contours and to obtain depth values of all surface of micropart. Simulation experiments are carried out to verify the proposed method by generating simulated MVTS image array from two simulation objects, and the influence parameters of the proposed method are analysed. In established experimental setup of microassembly that can realise MVTS, experimental verification for the proposed depth estimation method are carried out by using cone cavity and end jaws of microgripper. 3D morphologies of depth maps of cone cavity and end jaws of microgripper are registered with their respective CAD models using iterative nearest point registration algorithm to quantify accuracy of depth estimation. The research results show that 3D morphology of micropart can be obtained by the proposed method and has better accuracy than those by conventional shape from focus method. This method provides a new way to obtain the morphology of microparts and lays a foundation for improving the accuracy and efficiency of gripping, alignment and approaching microparts in microassembly systems.
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http://dx.doi.org/10.1111/jmi.13010DOI Listing
April 2021

Strategies for the detection of target analytes using microfluidic paper-based analytical devices.

Anal Bioanal Chem 2021 Apr 13;413(9):2429-2445. Epub 2021 Mar 13.

Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instruments, Key Laboratory of Thin Film and Microfabrication (Ministry of Education), Shanghai, 200240, China.

Microfluidic paper-based analytical devices (μPADs) have developed rapidly in recent years, because of their advantages, such as small sample volume, rapid detection rates, low cost, and portability. Due to these characteristics, they can be used for in vitro diagnostics in the laboratory, or in the field, for a variety of applications, including food evaluation, disease screening, environmental monitoring, and drug testing. This review will present various detection methods employed by μPADs and their respective applications for the detection of target analytes. These include colorimetry, electrochemistry, chemiluminescence (CL), electrochemiluminescence (ECL), and fluorescence-based methodologies. At the same time, the choice of labeling material and the design of microfluidic channels are also important for detection results. The construction of novel nanocomponents and different smart structures of paper-based devices have improved the performance of μPADs and we will also highlight some of these in this manuscript. Additionally, some key challenges and future prospects for the use of μPADs are briefly discussed.
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http://dx.doi.org/10.1007/s00216-021-03213-xDOI Listing
April 2021

Small extracellular vesicles containing miR-486-5p promote angiogenesis after myocardial infarction in mice and nonhuman primates.

Sci Transl Med 2021 Mar;13(584)

Department of Cardiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, PR China.

Stem cell-derived small extracellular vesicles (sEVs) promote angiogenesis after myocardial infarction (MI). However, the components of sEVs that contribute to these effects and the safety and efficiency of engineered sEV treatment for MI remain unresolved. Here, we observed improved cardiac function, enhanced vascular density, and smaller infarct size in mice treated with the sEVs from hypoxia-preconditioned (HP) mesenchymal stem cells (MSCs) (HP-sEVs) than in mice treated with normoxia-preconditioned (N) MSCs (N-sEVs). MicroRNA profiling revealed a higher abundance of miR-486-5p in HP-sEVs than in N-sEVs, and miR-486-5p inactivation abolished the benefit of HP-sEV treatment, whereas miR-486-5p up-regulation enhanced the benefit of N-sEV treatment. Matrix metalloproteinase 19 (MMP19) abundance was lower in HP-sEV-treated than N-sEV-treated mouse hearts but was enriched in cardiac fibroblasts (CFs), and was identified as one of the target genes of miR-486-5p. Conditioned medium from CFs that overexpressed miR-486-5p or silenced MMP19 increased the angiogenic activity of endothelial cells; however, medium from CFs that simultaneously overexpressed and miR-486-5p abolished this effect. silencing in CFs reduced the cleavage of extracellular vascular endothelial growth factor (VEGF). Furthermore, miR-486-5p-overexpressing N-sEV treatment promoted angiogenesis and cardiac recovery without increasing arrhythmia complications in a nonhuman primate (NHP) MI model. Collectively, this study highlights the key role of sEV miR-486-5p in promoting cardiac angiogenesis via fibroblastic MMP19-VEGFA cleavage signaling. Delivery of miR-486-5p-engineered sEVs safely enhanced angiogenesis and cardiac function in an NHP MI model and may promote cardiac repair.
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http://dx.doi.org/10.1126/scitranslmed.abb0202DOI Listing
March 2021

Direct Detection of Viable but Non-culturable (VBNC) Salmonella in Real Food System by a Rapid and Accurate PMA-CPA Technique.

Front Microbiol 2021 18;12:634555. Epub 2021 Feb 18.

Department of Civil and Environmental Engineering, University of Maryland, College Park, College Park, MD, United States.

is a typical foodborne pathogen with multiple toxic effects, including invasiveness, endotoxins, and enterotoxins. Viable but nonculturable (VBNC) is a type of dormant form preserving the vitality of microorganisms, but it cannot be cultured by traditional laboratory techniques. The aim of this study is to develop a propidium monoazide-crossing priming amplification (PMA-CPA) method that can successfully detect rapidly with high sensitivity and can identify VBNC cells in food samples. Five primers (4s, 5a, 2a/1s, 2a, and 3a) were specially designed for recognizing the specific gene. The specificity of the CPA assay was tested by 20 different bacterial strains, including 2 standard and 18 non- bacteria strains covering Gram-negative and Gram-positive isolates. Except for the two standard ATCC14028 and ATCC29629, all strains showed negative results. Moreover, PMA-CPA can detect the VBNC cells both in pure culture and three types of food samples with significant color change. In conclusion, the PMA-CPA assay was successfully applied on detecting in VBNC state from food samples.
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http://dx.doi.org/10.3389/fmicb.2021.634555DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930388PMC
February 2021

Batch Coherence-Driven Network for Part-Aware Person Re-Identification.

IEEE Trans Image Process 2021 9;30:3405-3418. Epub 2021 Mar 9.

Existing part-aware person re-identification methods typically employ two separate steps: namely, body part detection and part-level feature extraction. However, part detection introduces an additional computational cost and is inherently challenging for low-quality images. Accordingly, in this work, we propose a simple framework named Batch Coherence-Driven Network (BCD-Net) that bypasses body part detection during both the training and testing phases while still learning semantically aligned part features. Our key observation is that the statistics in a batch of images are stable, and therefore that batch-level constraints are robust. First, we introduce a batch coherence-guided channel attention (BCCA) module that highlights the relevant channels for each respective part from the output of a deep backbone model. We investigate channel-part correspondence using a batch of training images, then impose a novel batch-level supervision signal that helps BCCA to identify part-relevant channels. Second, the mean position of a body part is robust and consequently coherent between batches throughout the training process. Accordingly, we introduce a pair of regularization terms based on the semantic consistency between batches. The first term regularizes the high responses of BCD-Net for each part on one batch in order to constrain it within a predefined area, while the second encourages the aggregate of BCD-Net's responses for all parts covering the entire human body. The above constraints guide BCD-Net to learn diverse, complementary, and semantically aligned part-level features. Extensive experimental results demonstrate that BCD-Net consistently achieves state-of-the-art performance on four large-scale ReID benchmarks.
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http://dx.doi.org/10.1109/TIP.2021.3060909DOI Listing
March 2021

Early occupational exposure to lead on neutrophil-to-lymphocyte ratio and genotoxicity.

Environ Int 2021 06 19;151:106448. Epub 2021 Feb 19.

Department of Occupational Health & Toxicology, School of Public Health, Shanghai Medical College of Fudan University, 130 Dongan Road, Shanghai 200032, China. Electronic address:

Background: Lead (Pb) is known to induce detrimental health effects in exposed populations, including hematotoxicity and genotoxicity. Complete blood count (CBC) is a cost-effective and easy way to determine toxicity, and variations in proportion of different types of leukocytes: neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) are further evidence of hematotoxicity. However, few studies have been conducted to systematically evaluate effects of occupational Pb exposure on NLR and LMR, and their associations with genotoxicity.

Objectives: Our study was aimed to systematically assess the effects of current occupational Pb exposure on NLR and LMR, and their associations with genotoxicity.

Methods: Our investigation was performed on 1176 workers from a newly built battery factory in North China. The workers had just entered their current job position in recent years and most of them had no previous history of occupational exposure to Pb. Blood lead levels (BLLs) and leukocytes indices were detected for all participants. Cytokinesis-blocked micronucleus assay (MN; n = 675) and alkaline comet assay (% tail DNA; n = 869) were used to assess genotoxicity. Multivariate linear and Poisson regression analyses were conducted to examine associations between leukocytes indices, genotoxic biomarkers and BLLs with adjustment for covariates. Spearman correlation and mediation analyses were used to investigate relationships between NLR and genotoxicity.

Results: Among all the exposed workers, NLR increased with increasing BLLs. However, WBC and LMR did not change significantly. Significant and dose-dependent increases in both MN frequencies and % tail DNA were observed among groups with different exposure doses. Compared with the normal NLR group (1.48 ≤ NLR < 4.58), the high NLR group (NLR ≥ 4.58) had higher % tail DNA. In addition, there was a significant and positive association between NLR and % tail DNA among all the workers, and % tail DNA mediated 15% of the effect of Pb on increasing NLR.

Conclusion: Our large-scale population study shows that Pb exposure increased NLR and induced genotoxicity. There was an association between elevated NLR and DNA damage. In addition, the mediation effect of % tail DNA on the relationship between BLLs and NLR provided mechanistic evidence that certain mechanisms, e.g. inflammation, may be involved in elevation of NLR from Pb exposure. Therefore, NLR may be a convenient and sensitive biomarker for indication of Pb toxicity. Further studies are needed to validate the proposed mechanism and NLR as a biomarker.
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http://dx.doi.org/10.1016/j.envint.2021.106448DOI Listing
June 2021

Breath analysis based early gastric cancer classification from deep stacked sparse autoencoder neural network.

Sci Rep 2021 Feb 17;11(1):4014. Epub 2021 Feb 17.

Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering, Yantai Information Technology Research Institute of Shanghai Jiao Tong University, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.

Deep learning is an emerging tool, which is regularly used for disease diagnosis in the medical field. A new research direction has been developed for the detection of early-stage gastric cancer. The computer-aided diagnosis (CAD) systems reduce the mortality rate due to their effectiveness. In this study, we proposed a new method for feature extraction using a stacked sparse autoencoder to extract the discriminative features from the unlabeled data of breath samples. A Softmax classifier was then integrated to the proposed method of feature extraction, to classify gastric cancer from the breath samples. Precisely, we identified fifty peaks in each spectrum to distinguish the EGC, AGC, and healthy persons. This CAD system reduces the distance between the input and output by learning the features and preserve the structure of the input data set of breath samples. The features were extracted from the unlabeled data of the breath samples. After the completion of unsupervised training, autoencoders with Softmax classifier were cascaded to develop a deep stacked sparse autoencoder neural network. In last, fine-tuning of the developed neural network was carried out with labeled training data to make the model more reliable and repeatable. The proposed deep stacked sparse autoencoder neural network architecture exhibits excellent results, with an overall accuracy of 98.7% for advanced gastric cancer classification and 97.3% for early gastric cancer detection using breath analysis. Moreover, the developed model produces an excellent result for recall, precision, and f score value, making it suitable for clinical application.
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http://dx.doi.org/10.1038/s41598-021-83184-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7889910PMC
February 2021

Rapid developments in lateral flow immunoassay for nucleic acid detection.

Analyst 2021 Mar 17;146(5):1514-1528. Epub 2021 Feb 17.

Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai Engineering Research Center for Intelligent diagnosis and treatment instrument, Key Laboratory of Thin Film and Microfabrication Technology (Ministry of Education), Shanghai 200240, China.

Recently, lateral flow assay (LFA) for nucleic acid detection has drawn increasing attention in the point-of-care testing fields. Due to its rapidity, easy implementation, and low equipment requirement, it is well suited for use in rapid diagnosis, food authentication, and environmental monitoring under source-limited conditions. This review will discuss two main research directions of lateral flow nucleic acid tests. The first one is the incorporation of isothermal amplification methods with LFA, which ensures an ultra-high testing sensitivity under non-laboratory conditions. The two most commonly used methodologies will be discussed, namely Loop-mediated Isothermal Amplification (LAMP) and Recombinase Polymerase Amplification (RPA), and some novel methods with special properties will also be introduced. The second research direction is the development of novel labeling materials. It endeavors to increase the sensitivity and quantifiability of LFA testing, where signals can be read and analyzed by portable devices. These methods are compared in terms of limits of detection, detection times, and quantifiabilities. It is anticipated that future research on lateral flow nucleic acid tests will focus on the integration of the whole testing process into a microfluidic system and the combination with molecular diagnostic tools such as clustered regularly interspaced short palindromic repeats to facilitate a rapid and accurate test.
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http://dx.doi.org/10.1039/d0an02150dDOI Listing
March 2021

Multifunctional Nano-Sunflowers with Color-Magnetic-Raman Properties for Multimodal Lateral Flow Immunoassay.

Anal Chem 2021 02 9;93(7):3626-3634. Epub 2021 Feb 9.

State Key Lab of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China.

Multimodal lateral flow immunoassay (LFIA) has shown promise for improving both the flexibility and practicability of point-of-care test. We report here a facile, in situ growth method for preparing multifunctional core-shell-shell nano-sunflowers with a unique combination of color-magnetic-Raman properties. The use of FeO nanobeads with high saturation magnetization as the magnetic core allowed for robust magnetic signal strength-even after successive coatings of polydopamine and gold nanoparticles (Au NPs). Carefully selected 4-mercaptobenzonitrile molecules not only contributed to the growth of the Au NP shell but also generated a strong, surface-enhanced Raman scattering signal. The resulting nanomaterials were successfully used in the construction of multimodal LFIA with one qualitative and two alternative quantitative detection modes of different sensitivity levels. The limit of detection for the paradigm target-human chorionic gonadotropin-was 10 mIU/mL in color mode, 1.2 mIU/mL in magnetic mode, and 0.2 mIU/mL in Raman mode.
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http://dx.doi.org/10.1021/acs.analchem.0c05354DOI Listing
February 2021

webTDat: A Web-Based, Real-Time, 3D Visualization Framework for Mesoscopic Whole-Brain Images.

Front Neuroinform 2020 13;14:542169. Epub 2021 Jan 13.

School of Computer Science and Engineering, Xi'an University of Technology, Xi'an, China.

The popularity of mesoscopic whole-brain imaging techniques has increased dramatically, but these techniques generate teravoxel-sized volumetric image data. Visualizing or interacting with these massive data is both necessary and essential in the bioimage analysis pipeline; however, due to their size, researchers have difficulty using typical computers to process them. The existing solutions do not consider applying web visualization and three-dimensional (3D) volume rendering methods simultaneously to reduce the number of data copy operations and provide a better way to visualize 3D structures in bioimage data. Here, we propose webTDat, an open-source, web-based, real-time 3D visualization framework for mesoscopic-scale whole-brain imaging datasets. webTDat uses an advanced rendering visualization method designed with an innovative data storage format and parallel rendering algorithms. webTDat loads the primary information in the image first and then decides whether it needs to load the secondary information in the image. By performing validation on TB-scale whole-brain datasets, webTDat achieves real-time performance during web visualization. The webTDat framework also provides a rich interface for annotation, making it a useful tool for visualizing mesoscopic whole-brain imaging data.
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http://dx.doi.org/10.3389/fninf.2020.542169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7838507PMC
January 2021

Associations of blood lead levels with multiple genotoxic biomarkers among workers in China: A population-based study.

Environ Pollut 2020 Nov 30;273:116181. Epub 2020 Nov 30.

Department of Occupational Health & Toxicology, School of Public Health, Shanghai Medical College of Fudan University, 130 Dongan Road, Shanghai 200032, China. Electronic address:

Carcinogenic effects from low doses of lead (Pb) exposure to populations have been suspected but not concluded. Therefore, a large-scale cross-sectional study was conducted by us to investigate genotoxic effects from Pb exposure during 2016-2018 in North China. Blood lead levels (BLLs) and cumulative blood lead levels (CBLLs) were measured. Multiple relevant biomarkers were used to assess genotoxicity of Pb: mitochondrial DNA copy number (mtDNAcn, n = 871), Comet Tail Intensity (n = 872), γ-H2AX (n = 345), relative telomere length (rTL, n = 757), micronuclei (MN, n = 934) and phosphatidylinositol glycan class A mutation (PIG-A, n = 362). The BLL data show right-skewed distribution, with increase of the median (P, P) from 17.4 (8.9, 26.4) μg/dl in 2016 to 18.5 (10.5, 27.2) μg/dl in 2017, and to 20.8 (11.3, 31.0) μg/dl in 2018. Multivariate regression analyses show that mtDNAcn was non-linearly associated with BLLs or CBLLs, i.e. decreased at low levels but increased at the higher levels. Comet and Micronuclei data show positive dose-response relationships with BLLs as well as CBLLs. γ-H2AX data show an overall increased trend with BLLs while rTL data show a shortening trend. No associations were found for PIG-A mutation with Pb exposure. Our findings indicate that current low dose exposure to Pb can still cause health hazards to occupational populations, and the mechanism may be via the induction of DNA & chromosome damage rather than via the mutagenesis pathway.
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http://dx.doi.org/10.1016/j.envpol.2020.116181DOI Listing
November 2020

Catechol-Based Antimicrobial Polymers.

Molecules 2021 Jan 21;26(3). Epub 2021 Jan 21.

Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA.

Catechol is a key constituent in mussel adhesive proteins and is responsible for strong adhesive property and crosslinking formation. Plant-based polyphenols are also capable of chemical interactions similar to those of catechol and are inherently antimicrobial. This review reports a series of catechol-based antimicrobial polymers classified according to their antimicrobial mechanisms. Catechol is utilized as a surface anchoring group for adhering monomers and polymers of known antimicrobial properties onto various types of surfaces. Additionally, catechol's ability to form strong complexes with metal ions and nanoparticles was utilized to sequester these antimicrobial agents into coatings and polymer matrices. During catechol oxidation, reactive oxygen species (ROS) is generated as a byproduct, and the use of the generated ROS for antimicrobial applications was also introduced. Finally, polymers that utilized the innate antimicrobial property of halogenated catechols and polyphenols were reviewed.
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http://dx.doi.org/10.3390/molecules26030559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7865322PMC
January 2021

First Report on the Rapid Detection and Identification of Methicillin-Resistant (MRSA) in Viable but Non-culturable (VBNC) Under Food Storage Conditions.

Front Microbiol 2020 7;11:615875. Epub 2021 Jan 7.

Department of Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China.

Formation of viable but non-culturable (VBNC) status in methicillin-resistant (MRSA) has never been reported, and it poses a significant concern for food safety. Thus, this study aimed to firstly develop a rapid, cost-effective, and efficient testing method to detect and differentiate MRSA strains in the VBNC state and further apply this in real food samples. Two targets were selected for detection of MRSA and toxin, and rapid isothermal amplification detection assays were developed based on cross-priming amplification methodology. VBNC formation was performed for MRSA strain in both pure culture and in artificially contaminated samples, then propidium monoazide (PMA) treatment was further conducted. Development, optimization, and evaluation of PMA-crossing priming amplification (CPA) were further performed on detection of MRSA in the VBNC state. Finally, application of PMA-CPA was further applied for detection on MRSA in the VBNC state in contaminated food samples. As concluded in this study, formation of the VBNC state in MRSA strains has been verified, then two PMA-CPA assays have been developed and applied to detect MRSA in the VBNC state from pure culture and food samples.
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http://dx.doi.org/10.3389/fmicb.2020.615875DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7817642PMC
January 2021

Rapid Fabrication of Ready-to-Use Gelatin Scaffolds with Prevascular Networks Using Alginate Hollow Fibers as Sacrificial Templates.

ACS Biomater Sci Eng 2020 04 13;6(4):2297-2311. Epub 2020 Mar 13.

Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

In this study, we developed a facile manufacturing method for interconnected prevascular networks using calcium chloride (CaCl) cross-linked alginate hollow fibers as sacrificial templates. The resulting network can be used to deliver oxygen and nutrients and remove waste for embedded cells in large-volume gelatin scaffolds during culturing. The sacrificial templates were printed by customized coaxial nozzles and embedded in scaffolds made of a mixture of gelatin, microbial transglutaminase (mTG), and sodium citrate. During the cross-linking of gelatin and mTG, the sacrificial templates started to dissolve from the scaffold-template interface due to the presence of the sodium citrate in the gelatin. The embedded sacrificial templates were completely dissolved without any postprocessing, and the designed prevascular networks successfully retained their geometries and dimensions. No residue of the template was observed at the scaffold-template interface after dissolution, which promoted cell adhesion. This manufacturing method has a high degree of freedom in templates' geometry, which was demonstrated by fabricating prevascular networks with various designs, including grid, branched, and dendritic networks. The effects of hollow fiber size and sodium citrate concentration on the dissolution time were analyzed. Human umbilical vein endothelial cells were injected into the aforementioned networks and formed a confluent endothelial cell monolayer with high viability during the culture process. The results suggest great promise to rapidly build large-scale ready-to-use gelatin scaffolds with prevascular networks for the applications in tissue engineering.
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http://dx.doi.org/10.1021/acsbiomaterials.9b01834DOI Listing
April 2020

Spatial Difference and Equity Analysis for Accessibility to Three-Level Medical Services Based on Actual Medical Behavior in Shaanxi, China.

Int J Environ Res Public Health 2020 12 26;18(1). Epub 2020 Dec 26.

School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China.

The contradiction between the supply and demand of public medical resources in China is serious. On the basis of the "graded diagnosis and treatment" model, the Chinese government divides the medical grade and adjusts the allocation of medical facilities so as to alleviate the adverse impact of these issues on residents' health. Although the government tries to guide residents' medical treatment according to the level of medical facilities, there are differences between residents' medical treatment mode and policy rules in reality. Therefore, it is of great significance to explore spatial differences in accessibility to medical services for residents on the basis of the actual medical behavior. This article takes Shaanxi province as the research area, and uses the improved node cost network analysis method with the space-time distance model and the two-step floating catchment area method, respectively, to analyze the spatial differences of accessibility to three-level medical services and evaluate the equity of accessibility in different areas and groups in Shaanxi. Results showed that the overall level of accessibility to primary medical services in the province is good, and spatial distribution is balanced; the polarization of accessibility to secondary and tertiary medical services is a serious issue, and within the research area, a band-shaped multicore spatial structure was formed with the built-up areas of various cities as high-level centers of accessibility. Provincial residents have poor equity to access three-level medical services, and the equity of accessibility to primary medical services is better than that to highly specialized medical services. There is no obvious gap between accessibility to three-level medical services for the aging and the nonaging populations in Shaanxi, but the unfair phenomenon between agricultural and the nonagricultural populations is prominent. In addition, this article found that the improvement in traffic conditions can produce space-time convergence and effectively weaken spatial deprivation. Therefore, developing public transportation is an effective approach to improve the equity of accessibility to medical services.
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http://dx.doi.org/10.3390/ijerph18010112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795108PMC
December 2020

Acute respiratory response to individual particle exposure (PM, PM and PM) in the elderly with and without chronic respiratory diseases.

Environ Pollut 2021 Feb 17;271:116329. Epub 2020 Dec 17.

Department of Environmental Health, School of Public Health, Fudan University, Shanghai, 200032, China; Key Laboratory of Public Health Safety of the Ministry of Education, NHC Key Laboratory of Health Technology Assessment (Fudan University), Shanghai Typhoon Institute/CMA, Shanghai Key Laboratory of Meteorology and Health, Shanghai, 200030, China. Electronic address:

Limited data were on the acute respiratory responses in the elderly in response to personal exposure of particulate matter (PM). In order to evaluate the changes of airway inflammation and pulmonary functions in the elderly in response to individual exposure of particles (PM, PM and PM), we analyzed 43 elderly subjects with either asthma, chronic obstructive pulmonary disease (COPD) or Asthma COPD Overlap (ACO) and 40 age-matched subjects without asthma nor COPD in an urban community in Shanghai, China. Data were collected at the baseline and in 6 follow-ups from August 2016 to December 2018, once every 3 months except for the last twice with a 6-month interval. In each follow-up, pulmonary functions, fractional exhaled nitric oxide (FeNO), 7-day continuous personal exposure to airborne particles were measured. Multivariate linear mixed effect regression models were applied to investigate the quantitative changes of pulmonary functions and FeNO in two respective groups. The results showed that on average 4.7 follow-up visits were completed in each participant. In subjects with CRDs, an inter-quartile range (IQR) increase of personal exposure to PM, PM and PM was significantly associated with an average increase of FeNO(Lag1) of 6.7 ppb (95%CI 1.2, 9.9 ppb), 6.2 ppb (95%CI 1.5, 12.0 ppb) and 5.6 ppb (95%CI 1.5, 11.0 ppb), respectively, and an average decrease of FEV1(Lag2) of -3.6 L (95%CI -6.0, -1.1 L), -3.6 L (95%CI -6.4, -0.8 L) and -3.2 L (95%CI -5.8, -0.6 L), respectively, in the single-pollutant model. These associations remained consistent in the two-pollutant models adjusting for gaseous air pollutants. Stratified analysis showed that subjects with lower BMI, females and non-allergies were more sensitive to particle exposure. No robust significant effects were observed in the subjects without CRDs. Our study provided data on the susceptibility of the elderly with CRDs to particle exposure of PM and PM, and the modification effects by BMI, gender and history of allergies.
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http://dx.doi.org/10.1016/j.envpol.2020.116329DOI Listing
February 2021

Study on the Viable but Non-culturable (VBNC) State Formation of and Its Control in Food System.

Front Microbiol 2020 26;11:599739. Epub 2020 Nov 26.

Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, United States.

A Viable but non-culturable (VBNC) state is a bacterial survival strategy under reverse conditions. It poses a significant challenge for public health and food safety. In this study, the effect of external environmental conditions including acid, nutrition, and salt concentrations on the formation of VBNC states at low temperatures were investigated. Different acidity and nutritional conditions were then applied to food products to control the VBNC state formation. Four different concentration levels of each factor (acid, nutrition, and salt) were selected in a total of 16 experimental groups. Nutrition showed the highest influence on the VBNC state formation , followed by acid and salt. The addition of 1% acetic acid could directly kill cells and inhibit the formation of the VBNC state with a nutrition concentration of 25, 50, and 100%. A propidium monoazide-polymerase chain reaction (PMA-PCR) assay was applied and considered as a rapid and sensitive method to detect in VBNC state with the detection limit of 10 CFU/mL.
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http://dx.doi.org/10.3389/fmicb.2020.599739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726111PMC
November 2020

New insights into interaction of proteins in extracellular polymeric substances of activated sludge with ciprofloxacin using quartz crystal microbalance with dissipation.

Chemosphere 2021 Jan 25;263:128044. Epub 2020 Aug 25.

Department of Civil and Environmental Engineering, Ningbo University, Ningbo, 315211, China.

Proteins in extracellular polymeric substances play a vital role in adsorbing organic contaminants in biological wastewater treatment processes, but there is still lack of a fast and effective approach to monitor their interaction. Quartz crystal microbalance with dissipation (QCM-D) was used to investigate the binding and viscoelastic properties of ciprofloxacin (CIP) on extracellular proteins from activated sludge by a two-step sequential deposition method. A saturated viscoelastic monolayer of proteins was formed on the crystal by injecting 500 mg L extracellular proteins. Binding of CIP with the extracellular proteins film followed the pseudo-first-order kinetic equation and Langmuir model, with the maximum binding capacity of 172.4 mg g. The binding mass, energy dissipation, and reaction rate constant increased with increasing CIP concentration. A strong binding was obtained at pH 5, suggesting electrostatic interactions as the dominating binding mechanism. Cations inhibited CIP binding with extracellular proteins, probably due to cations competition. Two binding periods were distinguished according to the viscoelastic properties of CIP layer: viscous binding in the initial period and elastic towards binding saturation. Results highlighted QCM-D as an effective and real-time technique to evaluate the role of extracellular proteins in contaminants removal.
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http://dx.doi.org/10.1016/j.chemosphere.2020.128044DOI Listing
January 2021

Micro Electrochemical Milling of Micro Metal Parts with Rotating Ultrasonic Electrode.

Sensors (Basel) 2020 Nov 19;20(22). Epub 2020 Nov 19.

School of Mechanical, Electrical & Information Engineering, Shandong University, Weihai 264209, China.

With the rapid development of MEMS, the demand for metal microstructure is increasing. Micro electrochemical milling technology (MECM) is capable of manufacturing micro metallic devices or components based on the principle of electrochemical anode dissolution. To improve the capacity of MECM, this paper presents a compound method named ultrasonic vibration-assisted micro electrochemical milling technology (UA-MECM). Firstly, the simulation and mathematical model of UA-MECM process is established to explain the mechanism of ultrasonic vibration on micro electrochemical milling. Then, the effects of ultrasonic parameters, electrical parameters and feedrate on machining localization and surface quality are discussed considering sets of experiments. The surface roughness was effectively reduced from a 0.83 to a 0.26 µm with the addition of ultrasonic vibration. It turns out that ultrasonic vibration can obviously improve machining precision, efficiency and quality. Finally, two- and three-dimensional microstructures with good surface quality were successful fabricated. It shows that ultrasonic vibration-assisted electrochemical milling technology has excellent machining performance, which has potential and broad industrial application prospects.
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http://dx.doi.org/10.3390/s20226617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699155PMC
November 2020

Deep Learning on chromatographic data for Segmentation and Sensitive Analysis.

J Chromatogr A 2020 Dec 5;1634:461680. Epub 2020 Nov 5.

Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Yantai Information Technology Research Institute of SJTU, Shanghai Engineering Research Center for Intelligent diagnosis and treatment instrument, Shanghai 200240, China. Electronic address:

Lateral flow immunoassay (LFIA) is one of the most common methods in point-of-care testing, which is widely applied in some conditions for various applications. Image segmentation is an increasingly popular experimental paradigm to efficiently test the target area in LFIA. However, due to process pollution, and problems related to the experimental operation and irregular structure of the background of the reaction, currently available tools cannot be used to extract correct signals from these images, which affects the accuracy of detection. Machine learning has significantly improved modern biochemical analysis by pushing the limits of traditional techniques for the recognition and processing of images. In this paper, the U-Net, a variant of the convolutional neural network (CNN) is used for the quantitative analysis of LFIA images for the accurate quantification of single- and multi-target images. By graying, binarizing, and labeling different concentrations of test strips, the target area of LFIA images containing the T-/C-lines is extracted and obtained. Then it provides updated trends and directions for the development of LFIA technology. Several indicators are introduced to evaluate the proposed U-Net structure to verify the feasibility and effectiveness of its image processing capability. When the trained U-Net model was used to process images, the peak signal-to-noise ratio was 22.4 dB, significantly higher than prevalent methods in the area that have reported only a 4 dB improvement in the quality of the graphics. The intersection-over-union between samples also increased to above 93%. Our results show that the proposed method has significant potential for detecting a segmented target in an LFIA area, especially weak positive signals and multichannel detection. With other modifications, this deep learning method can be applied as a powerful tool to study rapid detection devices, systems, and biological images.
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http://dx.doi.org/10.1016/j.chroma.2020.461680DOI Listing
December 2020

A Gold Nanocluster Constructed Mixed-Metal Metal-Organic Network Film for Combating Implant-Associated Infections.

ACS Nano 2020 11 9;14(11):15633-15645. Epub 2020 Nov 9.

Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.

The development of modular strategies for programming self-assembled supramolecular architectures with distinct structural and functional features is of immense scientific interest. We reported on the intrinsic antibacterial capability of anionic amphiphilic gold nanoclusters (GNCs) capped by -mercaptobenzoic acid, which was closely related to the protonation level of terminal carboxylate groups. By using of the metal-ligand coordination-driven and solvent evaporation-induced self-assembly, we constructed GNCs-based mixed-metal metal-organic network (MM-MON) films on titanium disks as antibacterial nanocoatings. Taking the reasonable utilization of tetravalent metal ions M (Ti, Zr, Hf; hard Lewis acid) and bactericidal divalent metal ions M (Cu, Zn; borderline acid) co-incorporated metal-carboxylate coordination bonds, the MM-MON films exhibited superior stability due to the robust M-O bonds and M releasing behavior resulting from the labile M-O coordinating. Together, the MM-MON films integrated the bacteria-responsive character of GNCs, exceptional chemical stability, and greatly enhanced antibacterial activity, ultimately killing adherent bacteria and initiating a self-defensive function. In a rat model for subcutaneous implant-associated infection, the MM-MON nanocoating showed an approximately 2 and 1 log lower multidrug-resistant implant and tissue colonization, respectively. The generalizable modular strategy of the GNC-metal networks is amenable to facilitate the functionalization of metal surfaces for combating implant-associated infections.
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http://dx.doi.org/10.1021/acsnano.0c06446DOI Listing
November 2020