Publications by authors named "Haicong Shen"

13 Publications

  • Page 1 of 1

An electrochemical method for a rapid and sensitive immunoassay on digital microfluidics with integrated indium tin oxide electrodes coated on a PET film.

Analyst 2021 Jul 18;146(14):4473-4479. Epub 2021 Jun 18.

The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The key Laboratory of Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, P.R. China.

Electrochemical detection is the simplest analytical tool to be integrated into digital microfluidics (DMF). It offers the advantages of small size, with detector electrodes incorporated into the device by patterning, and high compatibility with portable analytical instruments. Indium tin oxide (ITO) coated on glass has been commonly used for the top plate of DMF due to its good conductivity and transparency. However, instability and the low current response of ITO electrodes patterned on glass hindered their application for immunoassays. It has been reported that ITO coated on polyethylene terephthalate (PET) has better conductivity, owing to its higher carrier concentration, faster mobility and lower resistivity. Herein, we investigated the use of ITO electrodes patterned on PET film as the top plate of DMF for a simple and stable electrochemical immunoassay using square wave voltammetry (SWV), with an excellent peak resolution and high sensitivity. A magnetic bead-based immunoassay for H5N1 antigen was performed on a DMF platform with a limit of detection of 0.6 ng mL in buffer and 18 ng mL in human serum. These results showed the good electrochemical performance of ITO coated on a PET film, a lightweight, shock resistant and cost-effective material, which is promising for DMF fabrication and transparent electrodes for various electroanalytical methods.
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http://dx.doi.org/10.1039/d1an00513hDOI Listing
July 2021

In situ Raman enhancement strategy for highly sensitive and quantitative lateral flow assay.

Anal Bioanal Chem 2021 Jun 5. Epub 2021 Jun 5.

Key Laboratory for Chemical Biology of Fujian Province, MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China.

As a paper-based analytical platform, lateral flow assay (LFA) gets benefit from the rapid analysis, low cost, high selectivity, good stability, and user-friendliness, and thus has been widely used in rapid screening or assisted diagnosis. Nevertheless, LFA still suffers from low detection sensitivity via the naked eye, limiting its applications to qualitative and semi-quantitative tests. To enhance the signal readout, various nanoparticle signal tags have been employed to replace traditional colloidal gold nanoparticles (AuNPs), such as fluorescent nanoparticles (FNPs), magnetic nanoparticles (MNPs), and Raman reporter-labeled nanoparticles. In particular, Raman reporter-labeled nanoparticles are extremely sensitive due to remarkable signal enhancement effect on metal surface. However, the application of LFA is still hampered by the poor stability of Raman reporter-labeled nanoparticles. Herein, we developed an in situ Raman enhancement strategy to create a surface-enhanced Raman scattering (SERS) signal on the AuNPs, shortened as "i-SERS," which not only preserves the original advantages of the colloidal gold strip (AuNPs-LFA), but also realizes highly sensitive and quantitative detection. We applied the i-SERS for procalcitonin (PCT) detection. The experimental process takes only 16 min, and the limit of detection (LOD) is 0.03 ng mL, far below the value using AuNPs-LFA. These results indicate that i-SERS assay was highly sensitive and suitable for the rapid detection of PCT.
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http://dx.doi.org/10.1007/s00216-021-03419-zDOI Listing
June 2021

A microfluidic-integrated lateral flow recombinase polymerase amplification (MI-IF-RPA) assay for rapid COVID-19 detection.

Lab Chip 2021 05;21(10):2019-2026

The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, The Key Laboratory of Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

The COVID-19 pandemic, caused by SARS-CoV-2, currently poses an urgent global medical crisis for which there remains a lack of affordable point-of-care testing (POCT). In particular, resource-limited areas need simple and easily disseminated testing solutions to manage the outbreak. In this work, a microfluidic-integrated lateral flow recombinase polymerase amplification (MI-IF-RPA) assay was developed for rapid and sensitive detection of SARS-CoV-2, which integrates the reverse transcription recombinase polymerase amplification (RT-RPA) and a universal lateral flow (LF) dipstick detection system into a single microfluidic chip. The single-chamber RT-RPA reaction components are mixed with running buffer, and then delivered to the LF detection strips for biotin- and FAM-labelled amplified analyte sequences, which can provide easily interpreted positive or negative results. Testing requires only a simple nucleic acid extraction and loading, then incubation to obtain results, approximately 30 minutes in total. SARS-CoV-2 armored RNA particles were used to validate the MI-IF-RPA system, which showed a limit of detection of 1 copy per μL, or 30 copies per sample. Chip performance was further evaluated using clinically diagnosed cases of COVID-19 and revealed a sensitivity of 97% and specificity of 100%, highly comparable to current reverse transcription-polymerase chain reaction (RT-PCR)-based diagnostic assays. This MI-IF-RPA assay is portable and comprises affordable materials, enabling mass production and decreased risk of contamination. Without the need for specialized instrumentation and training, MI-IF-RPA assay can be used as a complement to RT-PCR for low-cost COVID-19 screening in resource-limited areas.
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http://dx.doi.org/10.1039/d0lc01222jDOI Listing
May 2021

Aptamer Generated by Cell-SELEX for Specific Targeting of Human Glioma Cells.

ACS Appl Mater Interfaces 2021 Mar 8;13(8):9306-9315. Epub 2020 Oct 8.

MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Collaborative Innovation Center of Chemistry for Energy Materials, Key Laboratory for Chemical Biology of Fujian Province, State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

The most prevalent primary brain tumors are gliomas, which start in the glial cells. Although there have been significant technological advances in surgery and radio-chemotherapy, the prognosis and survival of patients with malignant gliomas remain poor. For routine diagnosis of glioma, computed tomography and magnetic resonance imaging primarily depend on anatomical changes and fail to detect the cellular changes that occur early in the development of malignant gliomas. Therefore, it is urgent to find effective molecular diagnostic tools to detect early stages of malignant gliomas. Currently, cell-based Systematic Evolution of Ligands by EXponential enrichment (cell-SELEX) technology is one effective tool to obtain DNA or RNA aptamers capable of differentiating the molecular signatures among different types of cell lines. Using cell-SELEX, we generated and characterized an aptamer, termed S6-1b, that can distinguish the molecular differences between glioma cell line SHG44 and human astrocytes. Under the conditions of 4 and 37 °C, respectively, the dissociation constants of aptamer-cell interaction were both measured in the low nanomolar range. The aptamer S6-1b also exhibited excellent selectivity, making it suitable for use in a complex biological environment. Furthermore, the aptamer can effectively target glioma cells for in vivo fluorescence imaging of tumors. The target type of aptamer S6-1b was identified as a cell membrane protein. Our work indicates that aptamer S6-1b has diagnostic and therapeutic potential to specifically deliver imaging or therapeutic agents to malignant gliomas.
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http://dx.doi.org/10.1021/acsami.0c11878DOI Listing
March 2021

Discovery of Aptamers Targeting the Receptor-Binding Domain of the SARS-CoV-2 Spike Glycoprotein.

Anal Chem 2020 07 2;92(14):9895-9900. Epub 2020 Jul 2.

The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

The World Health Organization has declared the outbreak of a novel coronavirus (SARS-CoV-2 or 2019-nCoV) as a global pandemic. However, the mechanisms behind the coronavirus infection are not yet fully understood, nor are there any targeted treatments or vaccines. In this study, we identified high-binding-affinity aptamers targeting SARS-CoV-2 RBD, using an ACE2 competition-based aptamer selection strategy and a machine learning screening algorithm. The values of the optimized CoV2-RBD-1C and CoV2-RBD-4C aptamers against RBD were 5.8 nM and 19.9 nM, respectively. Simulated interaction modeling, along with competitive experiments, suggests that two aptamers may have partially identical binding sites at ACE2 on SARS-CoV-2 RBD. These aptamers present an opportunity for generating new probes for recognition of SARS-CoV-2 and could provide assistance in the diagnosis and treatment of SARS-CoV-2 while providing a new tool for in-depth study of the mechanisms behind the coronavirus infection.
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http://dx.doi.org/10.1021/acs.analchem.0c01394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336720PMC
July 2020

A Rapid, Simple, and Low-Cost CD4 Cell Count Sensor Based on Blocking Immunochromatographic Strip System.

ACS Sens 2019 06 23;4(6):1508-1514. Epub 2019 May 23.

Department of Oncology, The First Affiliated Hospital , Jinan University , Guangzhou , Guangdong 510630 , China.

The counting of CD4 T lymphocytes (CD4 cells) is a critical test for evaluating the immune function of HIV-infected peoples and tumor patients. A rapid, simple, accurate, and low-cost CD4 cell counting method as a diagnostic tool is increasingly required in the clinic. We designed and developed a novel fluorescent immunochromatographic strips (ICS) system based on the blocking principle for counting CD4 cells. The strategy of this system is to count CD4 cells indirectly, by measuring the free CD4 antibodies that were not bound by CD4 cells. The fluorescent antibodies bound to CD4 cells were blocked at the filter pads, resulting in a decrease in fluorescence of free CD4 antibodies measured. The number of CD4 cells was inversely related to the fluorescence intensity. The CD4 count-ICSs exhibited a quasilinear response ( R = 0.96) to logarithmic CD4 cell concentrations in PBMC samples in the range of 50-1000 cells/μL. In addition, the CD4 count-ICSs reliably quantified CD4 cells in whole blood samples, where the assay exhibited a linear correlation ( R = 0.976) readout for CD4 cell concentrations ranging from 100 to 800 cells/μL. To validate the clinical applicability of this method, 54 blood samples were measured: the detection results showed a high correlation ( R > 0.97) with the flow cytometry (FCM) analysis. The fluorescent ICSs can be used to count CD4 cells in blood samples, which have a high coincidence rate with FCM analysis; therefore, the CD4 count ICS system is an excellent candidate method for CD4 cell counting in resource-limited settings.
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http://dx.doi.org/10.1021/acssensors.8b01628DOI Listing
June 2019

Integration of a 3D-printed read-out platform with a quantum dot-based immunoassay for detection of the avian influenza A (H7N9) virus.

Analyst 2019 Apr;144(8):2594-2603

Department of Bioengineering, Guangdong Province Engineering Research Center for antibody drug and immunoassay, Jinan University, Guangzhou 510632, PR China.

Outbreaks and potential epidemics of the highly pathogenic avian influenza virus pose serious threats to human health and the global economy. As such, its timely and accurate detection is critically important. In the present study, positive hybridoma cells (6B3) were obtained, which were used to secrete high-titer avian influenza virus (AIV) H7N9 monoclonal antibodies (H7N9 mAb). Based on these mAbs, quantum dot-based lateral flow immunochromatographic strips (QD-LFICS) were developed for AIV H7N9 detection. Under optimized conditions, results from a commercial fluorescent strip reader indicated that the limit of detection of QD-LFICS was 0.0268 HAU. To achieve rapid on-site testing, a mini 3D-printed read-out platform was fabricated to allow observation of QD-LFICS by the naked eye. More importantly, QD-LFICS were found to be practical and specific for the detection of actual samples compared with a real-time polymerase chain reaction.
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http://dx.doi.org/10.1039/c8an02336kDOI Listing
April 2019

A novel fluorescent immunochromatographic strip combined with pocket fluorescence observation instrument for rapid detection of PRV.

Anal Bioanal Chem 2018 Nov 24;410(29):7655-7661. Epub 2018 Sep 24.

Department of Bioengineering, Guangdong Province Engineering Research Center of Antibody drug and Immunoassay, Jinan University, Guangzhou, 510632, Guangdong, China.

Pseudorabies virus (PRV) is an acute and thermal infectious disease in domestic animals. Pigs are a main source of PRV infection, which causes high mortality rates for newborn infected piglets and high miscarriage rates for infected adults. Therefore, early control of PRV is necessary to avoid significant economic loss. We have developed a novel fluorescent immunochromatographic strip (F-ICS) for rapid, sensitive, and specific detection of PRV with a limit of detection (LOD) of 0.13 ng mL and a detection linear range (DLR) between 0.13 and 2.13 ng mL. The detection limit was about 10 times lower than the colloidal gold strip. In tests of clinical samples, the F-ICS was largely consistent with PCR results, indicating its practical clinical application. In addition, for easy observation of the F-ICS signal by eye, we present a matching 3D-printed pocket fluorescence observation instrument (PFOI) that allows for use of the F-ICS in the field as easily as conventional colloidal gold strips. Graphical Abstract ᅟ.
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http://dx.doi.org/10.1007/s00216-018-1379-xDOI Listing
November 2018

Practical immune-barometer sensor for trivalent chromium ion detection using gold core platinum shell nanoparticle probes.

Analyst 2018 Mar;143(6):1426-1433

Department of Bioengineering, Guangdong Province Engineering Research Center for antibody drug and immunoassay, Jinan University, Guangzhou 510632, PR China.

The technology progress of biosensors has markedly improved healthcare, disease diagnosis, environment monitoring, and food safety control over the past few decades. However, development of sensitive, robust, low-cost and portable assays for on-site bioanalysis is still a great challenge. In this study, we described a portable, feasible and miniaturized immune-barometer sensor (IBS), which can be used to sensitively measure the changes in a pressure signal, and we applied this IBS in the detection of Cr(iii). In this system, a competitive immunoassay was incorporated as a signaling technique for Cr(iii) detection. To generate a signal of pressure changes (ΔP), [email protected] (gold core platinum shell nanoparticles) were prepared for decomposing HO to generate O in a sealed chamber. The expansion of gas volume was accurately detected using a sensitive barometer in the sealed reaction chamber. The ΔP correlated well with Cr(iii) concentrations ranging from 0.39 to 25 ng mL. The limit of detection (LOD) of the IBS was estimated to be as low as 0.35 ng mL. Furthermore, the IBS has high specificity and high recovery for Cr(iii) detection in tap water samples (97.5%-108.7%) and in the Pearl River water samples (95.6%-110.2%). Compared with the traditional enzyme-linked immunosorbent assay (ELISA), the IBS was observed to be more sensitive, of low-cost and portable for the on-site detection of Cr(iii). Therefore, the IBS is a promising potential method for the detection of heavy metals in aqueous solutions and many other fields.
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http://dx.doi.org/10.1039/c7an02047cDOI Listing
March 2018

A turn-on competitive immunochromatographic strips integrated with quantum dots and gold nano-stars for cadmium ion detection.

Talanta 2018 Feb 3;178:644-649. Epub 2017 Oct 3.

Department of Bioengineering, Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering, Jinan University, Guangzhou 510632, PR China. Electronic address:

Immunochromatographic strips (ICSs) are inexpensive, simple, portable, and robust, and therefore have many uses in the medicinal, agricultural, and environmental industries. For detection of small molecules, current ICSs are competitive format (competitive ICSs, CICSs), which only offer a turn-off readout mode, and therefore lead to low sensitivity when evaluating results by the naked eye. To overcome this problem, we report a turn-on CICSs that relies on the ability of gold nano-stars (AuNSs) quenching the signal of quantum dots (QDs). This turn-on CICSs device was applied to detect cadmium ions (Cd). The linear detection range (LDR) of the turn-on CICSs was 0.25ng/mL-8ng/mL, and the detection of limit (LOD) was 0.18ng/mL. Compared with traditional turn-off CICSs, the sensitivity of the turn-on CICSs was enhanced by 32 times. The turn-on CICSs also has a high specificity and high recovery for the detection of Cd in Pearl River (95-112%) and tap water samples (103.5-116.67%). Therefore, we believe the turn-on CICSs offers great potential for the detection of other small molecules in clinical diagnostics, food safety investigations, and environment pollution monitoring.
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http://dx.doi.org/10.1016/j.talanta.2017.10.002DOI Listing
February 2018

A new lateral-flow immunochromatographic strip combined with quantum dot nanobeads and gold nanoflowers for rapid detection of tetrodotoxin.

Analyst 2017 Nov;142(23):4393-4398

Department of Bioengineering, Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering, Jinan University, Guangzhou 510632, PR China.

Tetrodotoxin (TTX) is a potent, low molecular weight analyte that can lead to fatal poisoning and requires a sensitive, rapid detection method. Here, we have developed a competitive, lateral-flow immunochromatographic strip combined with quantum dot nanobeads (QDNBs) and gold nanoflowers (AuNFs). This approach is called turn-on C-LFICS and it meets all testing requirements. Subsequent analysis revealed that this turn-on C-LFICS was rapid (8 min), sensitive (LOD = 0.2 ng mL), and quantitative (DLR = 1.56-100 ng mL), and had a positive signal readout (based on fluorescence quenching effects) for TTX detection. Moreover, it had superior signal brightness and a low background interference signal when compared with previous methods. Finally, it can function free of interference from the sample matrix and has a demonstrated recovery range of 85.5% to 119.7% in spiked samples. Taken together, these results show that our turn-on C-LFICS is an effective detection tool for TTX or other small molecules.
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http://dx.doi.org/10.1039/c7an01227fDOI Listing
November 2017

Aptamer-based fluorescence-quenching lateral flow strip for rapid detection of mercury (II) ion in water samples.

Anal Bioanal Chem 2017 Sep 20;409(22):5209-5216. Epub 2017 Jul 20.

Department of Bioengineering, Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering, Jinan University, Guangzhou, 510632, China.

Divalent mercury ion (Hg) is one of the most common and stable forms of mercury pollution. In this study, a skillfully designed lateral flow strip (LFS) was developed for sensitive detection of Hg in river water samples. Aptamer, a specific oligonucleotide probe, was used to selectively identify and target Hg instead of antibody in traditional immunechromatographic strips; and the fluorescence-quenching system was used to generate positive and low background florescence signals in the competitive-likely LFS. The linear detection range of the LFS for Hg was 0.13 ng mL to 4 ng mL and the limit of detection (LOD) was 0.13 ng mL. This test provided results in 15 min and demonstrated high specificity. For detection of Hg in river water, the results were consistent with inductively coupled plasma-mass spectrometry measurements. The aptamer-based fluorescence-quenching LFS was shown to provide a reliable, accurate method for rapid detection of mercury contamination. Graphical Abstract The principle of the aptamer-based fluorescence-quenching LFS.
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http://dx.doi.org/10.1007/s00216-017-0491-7DOI Listing
September 2017

A Portable Smart-Phone Readout Device for the Detection of Mercury Contamination Based on an Aptamer-Assay Nanosensor.

Sensors (Basel) 2016 Nov 8;16(11). Epub 2016 Nov 8.

Department of Bioengineering, Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering, Jinan University, Guangzhou 510632, China.

The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg, which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs). The MR S-phone-based AuNPs-aptamer colorimetric sensor system could reliably detect Hg in both tap water and Pearl River water samples and produced a linear colorimetric readout of Hg concentration in the range of 1 ng/mL-32 ng/mL with a correlation of 0.991, and a limit of detection (LOD) of 0.28 ng/mL for Hg. The detection could be quickly completed in only 20 min. Our novel mercury detection assay is simple, rapid, and sensitive, and it provides new strategies for the on-site detection of mercury contamination in any environment.
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http://dx.doi.org/10.3390/s16111871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5134530PMC
November 2016
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