Publications by authors named "Kaiyang Wang"

49 Publications

A multifunctional substance P-conjugated chitosan hydrochloride hydrogel accelerates full-thickness wound healing by enhancing synchronized vascularization, extracellular matrix deposition, and nerve regeneration.

Biomater Sci 2021 Jun;9(11):4199-4210

Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.

Due to the native skin limitations and the complexity of reconstructive microsurgery, advanced biomaterials are urgently required to promote wound healing for severe skin defects caused by accidents and disasters. Accumulating evidence has supported that substance P (SP) has a potential effect on skin regeneration. However, SP application is seriously impeded by its poor stability and oxidative reactions occurring during production, transportation, and storage. An SP-conjugated chitosan hydrochloride hydrogel (CSCl-SP) fabricated in this study demonstrated an enhanced capacity to repair full-thickness skin defects. CSCl-SP provided a stable in vitro delivery system for SP. The dissolution of CSCl-SP promoted the proliferation, migration, and tube formation, as well as angiogenesis-related gene and protein expression in human umbilical vein endothelial cells. CSCI-SP also stimulated the proliferation, migration, and production of anabolic growth factor in human fibroblasts. Moreover, CSCl-SP significantly promoted the neurite outgrowth in Neuro-2A cells. In vivo, CSCl-SP dramatically strengthened the vascularization, extracellular matrix deposition and remodeling, and nerve regeneration, thereby promoting efficient recovery of the full-thickness skin defect. Thus, synchronized multifunction of the CSCl-SP hydrogel makes it a promising and smart material for intractable skin defects.
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http://dx.doi.org/10.1039/d1bm00357gDOI Listing
June 2021

miR-4286 functions in osteogenesis and angiogenesis via targeting histone deacetylase 3 and alleviates alcohol-induced bone loss in mice.

Cell Prolif 2021 Jun 10;54(6):e13054. Epub 2021 May 10.

Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.

Objectives: Alcohol consumption is one of the leading factors contributing to premature osteopenia. MicroRNA (miRNA) coordinates a cascade of anabolic and catabolic processes in bone homeostasis and dynamic vascularization. The aim was to investigate the protective role of miR-4286 in alcohol-induced bone loss and its mechanism.

Materials And Methods: The effect of miR-4286 and alcohol on bone mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs) was explored via multiple in vitro assays, including cell proliferation, QPCR, Western blot, osteogenesis, angiogenesis etc miR-4286 directly regulated HDAC3 was investigated by luciferase reporter assay, and the function of HDAC3 was also explored in vitro. Moreover, alcohol-induced bone loss in mice was established to reveal the preventive effect of miR-4286 by radiographical and histopathological assays.

Results: In vitro, ethanol dramatically inhibited the proliferation and osteogenesis of BMSCs, and substantially impaired the proliferation and vasculogenesis of HUVECs. However, a forced overexpression of miR-4286 within BMSCs and HUVECs could largely abolish inhibitory effects by alcohol. Furthermore, alcohol-induced inhibition on osteogenic and vasculogenic functions was mediated by histone deacetylase 3 (HDAC3), and dual-luciferase reporter assay showed that HDAC3 was the direct binding target of miR-4286. In vivo, micro-CT scanning and histology assessment revealed that miR-4286 could prevent alcohol-induced bone loss.

Conclusions: We firstly demonstrated that miR-4286 might function via intimate osteogenesis-angiogenesis pathway to alleviate alcohol-induced osteopenia via targeting HDAC3.
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http://dx.doi.org/10.1111/cpr.13054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168416PMC
June 2021

Phase Tailoring of Ruddlesden-Popper Perovskite at Fixed Large Spacer Cation Ratio.

Small 2021 Apr 4:e2100560. Epub 2021 Apr 4.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, China.

Ruddlesden-Popper (RP) metal halide perovskites are considered as promising optoelectronic materials due to their good environmental stability and desirable optoelectronic properties. However, the phase composition and ordering in the deposited film, with a fixed ratio of large organic spacer cation in the precursor solution, are hard to be further tailored for specific optoelectronic applications. Herein, it is shown that even with a fixed spacer cation ratio, the phase composition and ordering can still be largely regulated by utilizing different crystallization kinetics of various cations with the inorganic octahedral lead halide. By using two different short cations to compete with the large spacer cation, the phase composition can be continuously tailored from thin multiple quantum wells (MQWs) dominated to 3D perovskite dominated. The phase ordering can be reversed from small n phases' prior to large n phases' prior near the substrate. Finally, with the same amount of large spacer cation protection, the perovskite can be tailored for both high-performance electroluminescence and photovoltaics with favorable energetic landscape for the corresponding desired first-order excitonic recombination and second-order free electron-hole recombination, respectively. This exploration substantially contributes to the understanding of precise phase engineering in RP perovskite and may provide a new insight into the design of multiple functional devices.
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http://dx.doi.org/10.1002/smll.202100560DOI Listing
April 2021

Sequential Release of Small Extracellular Vesicles from Bilayered Thiolated Alginate/Polyethylene Glycol Diacrylate Hydrogels for Scarless Wound Healing.

ACS Nano 2021 04 16;15(4):6352-6368. Epub 2021 Mar 16.

Department of Orthopaedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.

Excessive scar formation has adverse physiological and psychological effects on patients; therefore, a therapeutic strategy for rapid wound healing and reduced scar formation is urgently needed. Herein, bilayered thiolated alginate/PEG diacrylate (BSSPD) hydrogels were fabricated for sequential release of small extracellular vesicles (sEVs), which acted in different wound healing phases, to achieve rapid and scarless wound healing. The sEVs secreted by bone marrow derived mesenchymal stem cells (B-sEVs) were released from the lower layer of the hydrogels to promote angiogenesis and collagen deposition by accelerating fibroblast and endothelial cell proliferation and migration during the early inflammation and proliferation phases, while sEVs secreted by miR-29b-3p-enriched bone marrow derived mesenchymal stem cells were released from the upper layer of the hydrogels and suppressed excessive capillary proliferation and collagen deposition during the late proliferation and maturation phases. In a full-thickness skin defect model of rats and rabbit ears, the wound repair rate, angiogenesis, and collagen deposition were evaluated at different time points after treatment with BSSPD loaded with B-sEVs. Interestingly, during the end of the maturation phase in the model, tissues in the groups treated with BSSPD loaded with sEVs for sequential release ([email protected]) exhibited a more uniform vascular structure distribution, more regular collagen arrangement, and lower volume of hyperplastic scar tissue than tissues in the other groups. Hence, [email protected] based on skin repair phases was successfully designed and has considerable potential as a cell-free therapy for scarless wound healing.
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http://dx.doi.org/10.1021/acsnano.0c07714DOI Listing
April 2021

LC-MS-based plasma metabolomics study of the intervention effect of different polar parts of hawthorn on gastrointestinal motility disorder rats.

Biomed Chromatogr 2021 Jun 1;35(6):e5076. Epub 2021 Feb 1.

Department of Traditional Chinese Medicine Analysis, School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, China.

Dyspepsia, one of the most prevalent diseases of the digestive tract that impacts the quality of patient life, is mainly caused by gastrointestinal motility disorder. Hawthorn is a commonly used traditional Chinese medicine for treating dyspepsia, and has been proven to improve gastrointestinal motility. Herein, a rat model of gastrointestinal motility disorder was established by subcutaneous injection with atropine. The modeled rats were treated with four polar parts (T1-4 in descending polarity, corresponding to water, n-butanol, ethyl acetate and petroleum ether extracts, respectively) of hawthorn. Through metabolomics analysis, a total of 20 significantly metabolites were identified with significant changes in their abundance levels and these metabolites were related to many metabolic pathways such as amino acid metabolism and primary bile acid biosynthesis. The results showed that T3 had the best therapeutic effect of promoting gastrointestinal motility. Other parts showed no obvious therapeutic effect, demonstrating that the effective components of hawthorn may be compounds of medium polarity. T3 might achieve good therapeutic effects owing to the gastrointestinal motility promotion activity, and by rectifying the disturbed metabolic pathways in the gastrointestinal motility disorder model.
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http://dx.doi.org/10.1002/bmc.5076DOI Listing
June 2021

Transcatheter closure of a rare congenital left ventricle to right atrium shunt using the amplatzer duct occluder II: A case report.

Medicine (Baltimore) 2020 Nov;99(47):e22576

Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, Department of Pediatrics, West China Second University Hospital.

Rationale: Left ventricle-right atrium (LV-RA) shunt is a rare case and surgical repair has been the routine procedure to correct this defect. With the rapid development of transcatheter technology, some of the cases can be closed with transcatheter technique. Here, we would like to report a congenital LV-RA case who received transcatheter closure using the Amplazter duct occluder II (ADO II) and the short-term outcomes of this procedure.

Patient Concerns: A 2-year-old female presented a systolic murmur between the 2 to 3 sternal rib during the routine examination before kindergarten administration.

Diagnosis: The patient denied any cardiac surgery, endocarditis, trauma or cardiomyopathy. The echocardiography confirmed an abnormal shunt between left ventricle and right atrium located in the superior part of ventricular septum which is closed to septal tricuspid valve and anterior mitral valve, and the diameter of this shunt is 2 mm. Besides, the dilation of right atrium (40 mm) has been identified which was not a common clinical manifestation of typical ventricular septal defect. Angiography demonstrated the shunt driven from left ventricle to right atrium.

Intervention: An AGA ADO II device had been delivered to close the defect.

Outcome: Follow-up kept for 3 months. Echocardiography revealed completed closure of the shunt with normal movement and function valves. And no complication of arrhythmia has been recorded.

Lessons: This case report highlighted the administration of ADO II in some ventricular septal defect with superior location, and provided an essential experience of using ADO II to close long tunnel type LV-RA shunt.
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http://dx.doi.org/10.1097/MD.0000000000022576DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7676515PMC
November 2020

Autonomic perspiration in 3D-printed hydrogel actuators.

Sci Robot 2020 01;5(38)

Department of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14850, USA.

In both biological and engineered systems, functioning at peak power output for prolonged periods of time requires thermoregulation. Here, we report a soft hydrogel-based actuator that can maintain stable body temperatures via autonomic perspiration. Using multimaterial stereolithography, we three-dimensionally print finger-like fluidic elastomer actuators having a poly--isopropylacrylamide (PNIPAm) body capped with a microporous (~200 micrometers) polyacrylamide (PAAm) dorsal layer. The chemomechanical response of these hydrogel materials is such that, at low temperatures (<30°C), the pores are sufficiently closed to allow for pressurization and actuation, whereas at elevated temperatures (>30°C), the pores dilate to enable localized perspiration in the hydraulic actuator. Such sweating actuators exhibit a 600% enhancement in cooling rate (i.e., 39.1°C minute) over similar non-sweating devices. Combining multiple finger actuators into a single device yields soft robotic grippers capable of both mechanically and thermally manipulating various heated objects. The measured thermoregulatory performance of these sweating actuators (~107 watts kilogram) greatly exceeds the evaporative cooling capacity found in the best animal systems (~35 watts kilogram) at the cost of a temporary decrease in actuation efficiency.
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http://dx.doi.org/10.1126/scirobotics.aaz3918DOI Listing
January 2020

3D printable tough silicone double networks.

Nat Commun 2020 08 10;11(1):4000. Epub 2020 Aug 10.

Facebook Reality Labs, Redmond, WA, USA, 98052.

Additive manufacturing permits innovative soft device architectures with micron resolution. The processing requirements, however, restrict the available materials, and joining chemically dissimilar components remains a challenge. Here we report silicone double networks (SilDNs) that participate in orthogonal crosslinking mechanisms-photocurable thiol-ene reactions and condensation reactions-to exercise independent control over both the shape forming process (3D printing) and final mechanical properties. SilDNs simultaneously possess low elastic modulus (E < 700kPa) as well as large ultimate strains (dL/L up to ~ 400 %), toughnesses (U ~ 1.4 MJ·m), and strengths (σ ~ 1 MPa). Importantly, the latent condensation reaction permits cohesive bonding of printed objects to dissimilar substrates with modulus gradients that span more than seven orders of magnitude. We demonstrate soft devices relevant to a broad range of disciplines: models that simulate the geometries and mechanical properties of soft tissue systems and multimaterial assemblies for next generation wearable devices and robotics.
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http://dx.doi.org/10.1038/s41467-020-17816-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417997PMC
August 2020

Ultrashort laser pulse doubling by metal-halide perovskite multiple quantum wells.

Nat Commun 2020 Jul 17;11(1):3361. Epub 2020 Jul 17.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, 999078, Macao, China.

Multiple ultrashort laser pulses are widely used in optical spectroscopy, optoelectronic manipulation, optical imaging and optical signal processing etc. The laser pulse multiplication, so far, is solely realized by using the optical setups or devices to modify the output laser pulse from the optical gain medium. The employment of these external techniques is because the gain medium itself is incapable of modifying or multiplying the generated laser pulse. Herein, with single femtosecond laser pulse excitation, we achieve the double-pulsed stimulated emission with pulse duration of around 40 ps and pulse interval of around 70 ps from metal-halide perovskite multiple quantum wells. These unique stimulated emissions originate from one fast vertical and the other slow lateral high-efficiency carrier funneling from low-dimensional to high-dimensional quantum wells. Furthermore, such gain medium surprisingly possesses nearly Auger-free stimulated emission. These insights enable us a fresh approach to multiple the ultrashort laser pulse by gain medium.
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http://dx.doi.org/10.1038/s41467-020-17096-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368017PMC
July 2020

Tailoring the Surface Morphology and Phase Distribution for Efficient Perovskite Electroluminescence.

J Phys Chem Lett 2020 Aug 13;11(15):5877-5882. Epub 2020 Jul 13.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China.

Metal-halide perovskites are promising light-emitting materials due to their continually tunable emission peak, high color purity, high emission efficiency, and low cost. Incorporating some two-dimensional (2D) perovskites into the three-dimensional (3D) perovskite can facilitate carrier localization to the emitting area and reduce nonradiative recombination. However, the incorporated 2D perovskites typically contain diverse phases with different bandgaps and random distribution, which significantly limits the performance of perovskite light emitting diodes (PeLEDs). Furthermore, the morphology of the quasi-2D perovskite film is also a key issue to the device performance. Herein, through replacing part of FA with Cs, the phase distribution and morphology of perovskite film can be tailored simultaneously. When 20% of FA is replaced by Cs in the perovskite film, the charge transfer efficiency is enhanced and the current leakage is suppressed. Eventually, the efficiency of PeLED is almost doubled and the stability is also significantly improved.
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http://dx.doi.org/10.1021/acs.jpclett.0c01252DOI Listing
August 2020

Micro- and Nanostructured Lead Halide Perovskites: From Materials to Integrations and Devices.

Adv Mater 2021 Feb 23;33(6):e2000306. Epub 2020 Jun 23.

Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, P. R. China.

In the past decade, lead halide perovskites have been intensively explored due to their promising future in photovoltaics. Owing to their remarkable material properties such as solution processability, nice defect tolerance, broad bandgap tunability, high quantum yields, large refractive index, and strong nonlinear effects, this family of materials has also shown advantages in many other optoelectronic devices including microlasers, photodetectors, waveguides, and metasurfaces. Very recently, the stability of perovskite devices has been improved with the optimization of synthesis methods and device architectures. It is widely accepted that it is the time to integrate all the perovskite devices into a real system. However, for integrated photonic circuits, the shapes and distributions of chemically synthesized perovskites are quite random and not suitable for integration. Consequently, controlled synthesis and the top-down fabrication process are highly desirable to break the barriers. Herein, the developments of patterning and integration techniques for halide perovskites, as well as the structure/function relationships, are systematically reviewed. The recent progress in the study of optical responses originating from nanostructured perovskites is also presented. Lastly, the challenges and perspective for nanostructured-perovskite devices are discussed.
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http://dx.doi.org/10.1002/adma.202000306DOI Listing
February 2021

Effective Surface Ligand-Concentration Tuning of Deep-Blue Luminescent FAPbBr Nanoplatelets with Enhanced Stability and Charge Transport.

ACS Appl Mater Interfaces 2020 Jul 6;12(28):31863-31874. Epub 2020 Jul 6.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999078, China.

Metal-halide perovskite-based green and red light-emitting diodes (LEDs) have witnessed a rapid development because of their facile synthesis and processability; however, the blue-band emission is constrained by their unstable chemical properties and poorly conducting emitting layers. Here, we show a trioctylphosphine oxide (TOPO)-mediated one-step approach to realize bright deep-blue luminescent FAPbBr nanoplatelets (NPLs) with enhanced stability and charge transport. The concentration of NPL surface ligands is shown to be progressively tuned via varying the amount of intermediate TOPO due to the acid-base equilibrium between protic acid and TOPO. By effectively optimizing the concentration of surface ligands, the structural integrity of NPL solids can be preserved in ambient air for a week, mainly because of the highly ordered and dense solid assembly and the reduced defects. The removal of excess organic ligands also enables the improvement of charge mobility by orders of magnitude. Ultimately, ultrapure deep-blue perovskite LEDs (439 nm) with a narrow emission width of 14 nm and a peak EQE of 0.14% are achieved at low driving voltage. Our finding expands the current understanding of surface ligand modulation in the development of pure bromide deep-blue perovskite optoelectronics.
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http://dx.doi.org/10.1021/acsami.0c08552DOI Listing
July 2020

Superior Mid- to Long-Term Clinical Outcomes of Mobile-Bearing Total Knee Arthroplasty Compared to Fixed-Bearing: A Meta-analysis Based on a Minimum of 5 Years of Study.

J Knee Surg 2020 Jun 5. Epub 2020 Jun 5.

Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.

As more patients undergo total knee arthroplasty (TKA) each year, and the average age of patients gets younger, the patients are generally more active requiring a greater physiological demand and increasing range of motion on the prosthesis than the previous patients. However, there is no consensus on the optimal TKA tibial bearing design. We performed this systematic review to compare the clinical differences between mobile and fixed bearing constructs used in contemporary TKA. We searched PubMed, EMBASE, and Cochrane Library databases, identifying 515 total publications, including 17 randomized controlled trials (RCTs). A meta-analysis was performed, while the quality and bias of the evidence were rated according to the Grading of Recommendations Assessment Development and Evaluation (GRADE) guidelines and the Cochrane Database questionnaire. The meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Seventeen studies were included, with a total of 1505 knees receiving a mobile bearing TKA and 1550 knees receiving a fixed bearing TKA. The meta-analysis compared clinical outcomes between mobile bearing (MB)-TKA and fixed bearing (FB)-TKA using postoperative Knee Society Score, postoperative ROM, and survivorship and showed that there was a distinct difference in Knee Society Score between the mobile-bearing and fixed-bearing groups (overall standardized mean difference = 1.38; 95% confidence interval (CI): 0.50-2.25;  = 0.002; I = 60%). Patients treated with mobile-bearing prostheses were more likely to report good or excellent range of motion results (overall standardized mean difference = 2.06; 95% CI: 0.65-3.47;  = 0.004). No difference in implant survivorship or reoperation rate were identified. The fixed-bearing and mobile-bearing TKA designs are both capable of producing excellent long-term results with excellent clinical outcomes if properly implanted; however, the mobile-bearing TKA have superiority in mid- to long-term clinical results. Trial registration number for PROSPERO was CRD42019126402.
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http://dx.doi.org/10.1055/s-0040-1709490DOI Listing
June 2020

Where should the pins be placed to decrease the failure rate after fixation of a Mayo IIA olecranon fracture? A biomechanical analysis.

Injury 2020 Jul 19;51(7):1522-1526. Epub 2020 May 19.

Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, PR China. Electronic address:

Background: Clinically, treatment of Mayo IIA olecranon fractures (MIOF) using pins is associated with a high rate of failure. The purpose of our study was to compare the biomechanical stability and strength of four different fracture fixation configurations and to recommend the best method for the clinical treatment of MIOFs.

Methods: Twenty synthetic ulnar models were created and equally divided into 4 different fracture fixation groups: a double cortical configuration using Kirschner (K) wires; a double cortical configuration using transcortical pins; an intramedullary pin system; and an intramedullary pin system with a 3-mm distance between the eyelet and the proximal end of the olecranon (loose fixation). The stiffness and strength of all specimens were tested under a loading rate of 2 mm/min. Between-group differences were evaluated using an independent t-test, with significance set at P < 0.05.

Results: Stiffness and strength were significantly better for the K-wire than intramedullary group: stiffness, 63.467±14.063 N/mm and 36.243±5.625 N/mm, respectively (P=0.009); and strength, 624.293±148.728 N and 406.486±74.109 N, respectively (P=0.019). There was no difference in stiffness (P=0.370) or strength (P=0.929) between the use of transcortical pins and K-wires. Moreover, a 3-mm prominence of the pin at the olecranon did not have a negative effect on either stiffness (P=0.494) or strength (P=0.391).

Conclusions: Our biomechanical analysis indicated that using a double cortical pin configuration provided the best stability and strength and, thus, may lower the risk of fracture fixation failure. The use of either K-wires or pins in the double cortical configuration did not influence fixation stability. A loose double cortical configuration might decrease fracture stability, although there differences were not significant.
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http://dx.doi.org/10.1016/j.injury.2020.04.018DOI Listing
July 2020

3D Printing of Viscoelastic Suspensions via Digital Light Synthesis for Tough Nanoparticle-Elastomer Composites.

Adv Mater 2020 Jun 17;32(25):e2001646. Epub 2020 May 17.

Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14853, USA.

The rheological parameters required to print viscoelastic nanoparticle suspensions toward tough elastomers via Digital Light Synthesis (DLS) (an inverted projection stereolithography system) are reported. With a model material of functionalized silica nanoparticles suspended in a poly(dimethylsiloxane) matrix, the rheological-parameters-guided DLS can print structures seven times tougher than those formed from the neat polymers. The large yield stress and high viscosity associated with these high concentration nanoparticle suspensions, however, may prevent pressure-driven flow, a mechanism essential to stereolithography-based printing. Thus, to better predict and evaluate the printability of high concentration nanoparticle suspensions, the boundary of rheological properties compatible with DLS is defined using a non-dimensional Peclet number (Pe). Based on the proposed analysis of rheological parameters, the border of printability at standard temperature and pressure (STP) is established by resin with a silica nanoparticle mass fraction (ϕ ) of 0.15. Above this concentration, nanoparticle suspensions have Pe > 1 and are not printable. Beyond STP, the printability can be further extended to ϕ = 0.20 via a heating module with lower shear rate to reduce the Pe < 1. The printed rubber possesses even higher toughness (Γ ≈ 155 kJ m ), which is 40% higher over that of ϕ = 0.15.
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http://dx.doi.org/10.1002/adma.202001646DOI Listing
June 2020

Morphology Control of Doped Spiro-MeOTAD Films for Air Stable Perovskite Solar Cells.

Small 2020 May 19;16(18):e1907513. Epub 2020 Apr 19.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau, 999078, China.

Doped 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeOTAD), which acts as a hole-transporting layer (HTL), endows perovskite solar cells (PSCs) with excellent performance. However, the intrinsically hygroscopic nature of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dopants also aggravates the moisture instability of PSCs. In this work, the origins of the moisture instability of spiro-MeOTAD HTLs are explored and strategies to enhance moisture resistance are proposed. After 780 h of aging in air, 52% of the initial power conversion efficiency (PCE) can be sustained by prolonging the mixing time of the precursor solution of spiro-MeOTAD to reduce accumulated LiTFSI. In contrast, only 7% of the initial PCE remains if the precursor solution is mixed briefly. By thermally annealing an HTL to evaporate residual tBP in spiro-MeOTAD, pinholes are completely eliminated and 65% of the initial PCE remains after the same aging time. In this study, the significance of the initial morphology of spiro-MeOTAD HTLs on device stability is analyzed and strategies based on physical morphology for controlling PSC moisture instability induced by HTL dopants are developed.
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http://dx.doi.org/10.1002/smll.201907513DOI Listing
May 2020

Image Reconstruction with the Fourier Coefficients for Magnetic Induction Tomography.

Curr Med Imaging Rev 2020 ;16(2):156-163

School of Information Science & Engineering, Northeastern University, Shenyang 110819, China.

Background: Image reconstruction of magnetic induction tomography (MIT) is a typical ill-posed inverse problem, which means that the measurements are always far from enough. Thus, MIT image reconstruction results using conventional algorithms such as linear back projection and Landweber often suffer from limitations such as low resolution and blurred edges.

Methods: In this paper, based on the recent finite rate of innovation (FRI) framework, a novel image reconstruction method with MIT system is presented.

Results: This is achieved through modeling and sampling the MIT signals in FRI framework, resulting in a few new measurements, namely, fourier coefficients. Because each new measurement contains all the pixel position and conductivity information of the dense phase medium, the illposed inverse problem can be improved, by rebuilding the MIT measurement equation with the measurement voltage and the new measurements. Finally, a sparsity-based signal reconstruction algorithm is presented to reconstruct the original MIT image signal, by solving this new measurement equation.

Conclusion: Experiments show that the proposed method has better indicators such as image error and correlation coefficient. Therefore, it is a kind of MIT image reconstruction method with high accuracy.
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http://dx.doi.org/10.2174/1573405615666190126130905DOI Listing
January 2020

Preparation of high-efficiency near-infrared aggregation-induced emission nanoparticles based on FRET and their use in bio-imaging.

Methods Appl Fluoresc 2020 Feb 3;8(1):015007. Epub 2020 Feb 3.

School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, People's Republic of China.

Recently, the development of fluorescent probes has contributed to significant advances in cell biology and medical diagnostic imaging. In this work, we use biocompatible bovine hemoglobin (BHb) molecules to co-coat aggregation-induced emission (AIE) molecules amino tetraphenylethylene (TPE-NH) and near-infrared emission molecules 2-(4-aminophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl) fumaronitrile (TPAADFN), to get TPE-NH/[email protected] nanoparticles. Due to the fluorescence resonance energy transfer (FRET) between the two fluorescent molecules, the prepared fluorescent nanoparticles have high fluorescence quantum efficiency. The prepared TPE-NH/[email protected] nanoparticles also have large Stokes shift, which helps to avoid the cross-talk between the absorption and emission of the particles themselves. This is beneficial to avoid the self-absorption of biological tissues and obtain very high detection sensitivity. Furthermore, due to the good biocompatibility of BHb, TPE-NH/[email protected] nanoparticles have good mono-dispersity, low toxicity and high brightness, which is very propitious in the application of bio-imaging.
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http://dx.doi.org/10.1088/2050-6120/ab6704DOI Listing
February 2020

Size-Controlled Patterning of Single-Crystalline Perovskite Arrays toward a Tunable High-Performance Microlaser.

ACS Appl Mater Interfaces 2020 Jan 2;12(2):2662-2670. Epub 2020 Jan 2.

Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering , University of Macau , Avenida da Universidade , Taipa , Macau 999078 , China.

Single-crystalline halide perovskites with regular morphology are of great significance for laser applications because they can be used to fabricate a natural whispering-gallery-mode resonator. Although enormous efforts have been put to synthesize single-crystalline perovskites, controlling the lateral size and thickness of the crystal, particularly at the nanoscale, is still challenging. Here, we report a facile and high-throughput strategy to selectively one-step create micro/nanoscale size-controlled all-inorganic perovskite single-crystal arrays by surface-tension-confined evaporative assembly. Our method can be used to easily tune the single crystal size and selectively position the single crystal, with versatility in fabricating perovskite single-crystal arrays in a wafer scale. When the patterned size increases from 2 to 25 μm, the width of the CsPbClBr perovskite microplates increased from 150 nm to 4.2 μm. Fixing the width of the microplates at 1.6 μm, with the increase of the sliding speed from 50 to 250 mm/min, we could significantly control the thicknesses from 270 to 430 nm. Additionally, our present study provides a characterization of lasers based on different three-dimensional structures, confirming their width-dependent lasing mode and thickness-dependent lasing threshold characteristic, which is beneficial for the tunability of a high-performance microlaser.
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http://dx.doi.org/10.1021/acsami.9b18512DOI Listing
January 2020

Stereolithography for Personalized Left Atrial Appendage Occluders.

Adv Mater Technol 2018 Dec 21;3(12). Epub 2018 Sep 21.

Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.

Advancements in 3D additive manufacturing have spurred the development of effective patient-specific medical devices. Prior applications are limited to hard materials, however, with few implementations of soft devices that better match the properties of natural tissue. This paper introduces a rapid, low cost, and scalable process for fabricating soft, personalized medical implants via stereolithography of elastomeric polyurethane resin. The effectiveness of this approach is demonstrated by designing and manufacturing patient-specific endocardial implants. These devices occlude the left atrial appendage, a complex structure within the heart prone to blood clot formation in patients with atrial fibrillation. Existing occluders permit residual blood flow and can damage neighboring tissues. Here, the robust mechanical properties of the hollow, printed geometries are characterized and stable device anchoring through in vitro benchtop testing is confirmed. The soft, patient-specific devices outperform non-patient-specific devices in embolism and occlusion experiments, as well as in computational fluid dynamics simulations.
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http://dx.doi.org/10.1002/admt.201800233DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6892588PMC
December 2018

Robust Ag/ZrO/WS/Pt Memristor for Neuromorphic Computing.

ACS Appl Mater Interfaces 2019 Dec 13;11(51):48029-48038. Epub 2019 Dec 13.

National-Local Joint Engineering Laboratory of New Energy Photovoltaic Devices, Machine Vision Engineering Technology Center of Hebei Province, Key Laboratory of Digital Medical Engineering of Hebei Province, College of Electron and Information Engineering , Hebei University , Baoding 071002 , P. R. China.

The development of the information age has made resistive random access memory (RRAM) a critical nanoscale memristor device (MD). However, due to the randomness of the area formed by the conductive filaments (CFs), the RRAM MD still suffers from a problem of insufficient reliability. In this study, the memristor of Ag/ZrO/WS/Pt structure is proposed for the first time, and a layer of two-dimensional (2D) WS nanosheets was inserted into the MD to form 2D material and oxide double-layer MD (2DOMD) to improve the reliability of single-layer devices. The results indicate that the electrochemical metallization memory cell exhibits a highly stable memristive switching and concentrated ON- and OFF-state voltage distribution, high speed (∼10 ns), and robust endurance (>10 cycles). This result is superior to MDs with a single-layer ZrO or WS film because two layers have different ion transport rates, thereby limiting the rupture/rejuvenation of CFs to the bilayer interface region, which can greatly reduce the randomness of CFs in MDs. Moreover, we used the handwritten recognition dataset (i.e., the Modified National Institute of Standards and Technology (MNIST) database) for neuromorphic simulations. Furthermore, biosynaptic functions and plasticity, including spike-timing-dependent plasticity and paired-pulse facilitation, have been successfully achieved. By incorporating 2D materials and oxides into a double-layer MD, the practical application of RRAM MD can be significantly enhanced to facilitate the development of artificial synapses for brain-enhanced computing systems in the future.
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http://dx.doi.org/10.1021/acsami.9b17160DOI Listing
December 2019

Charge Carrier Dynamics and Broad Wavelength Tunable Amplified Spontaneous Emission in ZnCdSe Nanowires.

J Phys Chem Lett 2019 Dec 25;10(23):7516-7522. Epub 2019 Nov 25.

Institute of Applied Physics and Materials Engineering , University of Macau , Avenida da Universidade, Taipa , Macau 999078 , PR China.

ZnCdSe is regarded as a promising semiconducting material for optoelectronic devices. However, the tunable amplified spontaneous emission (ASE) properties and corresponding charge carrier recombination dynamics in ZnCdSe (0 ≤ ≤ 1) nanowires (NWs) remain poorly understood. Herein, the charge carrier dynamics and ASE properties in ZnCdSe NWs were systematically investigated. In these NWs, the one/two-photon pumped ASE wavelength across the entire visible spectrum (480-725 nm) can be easily tuned via compositional engineering. The ASE threshold is closely related to the absorption coefficient and PL lifetime. At room temperature, free-carrier recombination is dominated in the low fluence pumped PL process. The ASE behavior is determined by exciton recombination in the high pump fluence (>10 cm) region. These findings uncover the origin of the tunable PL/ASE properties in ZnCdSe NWs and establish them as having practical application as a series of lasing gain materials.
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http://dx.doi.org/10.1021/acs.jpclett.9b03051DOI Listing
December 2019

A New Memristor with 2D Ti C T MXene Flakes as an Artificial Bio-Synapse.

Small 2019 06 8;15(25):e1900107. Epub 2019 May 8.

State Key Laboratory of ASIC and System School of Microelectronics, Fudan University, Shanghai, 200433, China.

Two-dimensional (2D) materials have attracted extensive research interest in academia due to their excellent electrochemical properties and broad application prospects. Among them, 2D transition metal carbides (Ti C T ) show semiconductor characteristics and are studied widely. However, there are few academic reports on the use of 2D MXene materials as memristors. In this work, reported is a memristor based on MXene Ti C T flakes. After electroforming, Al/Ti C T /Pt devices exhibit repeatable resistive switching (RS) behavior. More interestingly, the resistance of this device can be continuously modulated under the pulse sequence with 10 ns pulse width, and the pulse width of 10 ns is much lower than that in other reported work. Moreover, on the nanosecond scale, the transition from short-term plasticity to long-term plasticity is achieved. These two properties indicate that this device is favorable for ultrafast biological synapse applications and high-efficiency training of neural networks. Through the exploration of the microstructure, Ti vacancies and partial oxidation are proposed as the origins of the physical mechanism of RS behavior. This work reveals that 2D MXene Ti C T flakes have excellent potential for use in memristor devices, which may open the door for more functions and applications.
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http://dx.doi.org/10.1002/smll.201900107DOI Listing
June 2019

Vacancy-Induced Synaptic Behavior in 2D WS Nanosheet-Based Memristor for Low-Power Neuromorphic Computing.

Small 2019 06 2;15(24):e1901423. Epub 2019 May 2.

Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, P. R. China.

Memristors with nonvolatile memory characteristics have been expected to open a new era for neuromorphic computing and digital logic. However, existing memristor devices based on oxygen vacancy or metal-ion conductive filament mechanisms generally have large operating currents, which are difficult to meet low-power consumption requirements. Therefore, it is very necessary to develop new materials to realize memristor devices that are different from the mechanisms of oxygen vacancy or metal-ion conductive filaments to realize low-power operation. Herein, high-performance and low-power consumption memristors based on 2D WS with 2H phase are demonstrated, which show fast ON (OFF) switching times of 13 ns (14 ns), low program current of 1 µA in the ON state, and SET (RESET) energy reaching the level of femtojoules. Moreover, the memristor can mimic basic biological synaptic functions. Importantly, it is proposed that the generation of sulfur and tungsten vacancies and electron hopping between vacancies are dominantly responsible for the resistance switching performance. Density functional theory calculations show that the defect states formed by sulfur and tungsten vacancies are at deep levels, which prevent charge leakage and facilitate the realization of low-power consumption for neuromorphic computing application.
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http://dx.doi.org/10.1002/smll.201901423DOI Listing
June 2019

All-optical control of lead halide perovskite microlasers.

Nat Commun 2019 04 16;10(1):1770. Epub 2019 Apr 16.

State Key Laboratory on Tunable laser Technology, Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, 518055, China.

Lead halide perovskites based microlasers have recently shown their potential in nanophotonics. However, up to now, all of the perovskite microlasers are static and cannot be dynamically tuned in use. Herein, we demonstrate a robust mechanism to realize the all-optical control of perovskite microlasers. In lead halide perovskite microrods, deterministic mode switching takes place as the external excitation is increased: the onset of a new lasing mode switches off the initial one via a negative power slope, while the main laser characteristics are well kept. This mode switching is reversible with the excitation and has been explained via cross-gain saturation. The modal interaction induced mode switching does not rely on sophisticated cavity designs and is generic in a series of microlasers. The switching time is faster than 70 ps, extending perovskite microlasers to previously inaccessible areas, e.g., optical memory, flip-flop, and ultrafast switches etc.
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http://dx.doi.org/10.1038/s41467-019-09876-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6467983PMC
April 2019

Simple Synthesis of Elastomeric Photomechanical Switches That Self-Heal.

Macromol Rapid Commun 2019 Feb 2;40(4):e1800815. Epub 2019 Jan 2.

Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14850, USA.

This article introduces a simple two-stage method to synthesize and program a photomechanical elastomer (PME) for light-driven artificial muscle-like actuations in soft robotics. First, photochromic azobenzene molecules are covalently attached to a polyurethane backbone via a two-part step-growth polymerization. Next, mechanical alignment is applied to induce anisotropic deformations in the PME-actuating films. Cross-linked through dynamic hydrogen bonds, the PMEs also possess autonomic self-healing properties without external energy input. This self-healing allows for a single alignment step of the PME film and subsequent "cut and paste" assembly for multi-axis actuation of a self-folded soft-robotic gripper from a single degree of freedom optical input.
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http://dx.doi.org/10.1002/marc.201800815DOI Listing
February 2019

Self-Assembled Networked PbS Distribution Quantum Dots for Resistive Switching and Artificial Synapse Performance Boost of Memristors.

Adv Mater 2019 Feb 27;31(7):e1805284. Epub 2018 Dec 27.

State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai, 200433, China.

With the advent of the era of big data, resistive random access memory (RRAM) has become one of the most promising nanoscale memristor devices (MDs) for storing huge amounts of information. However, the switching voltage of the RRAM MDs shows a very broad distribution due to the random formation of the conductive filaments. Here, self-assembled lead sulfide (PbS) quantum dots (QDs) are used to improve the uniformity of switching parameters of RRAM, which is very simple comparing with other methods. The resistive switching (RS) properties of the MD with the self-assembled PbS QDs exhibit better performance than those of MDs with pure-Ga O and randomly distributed PbS QDs, such as a reduced threshold voltage, uniformly distributed SET and RESET voltages, robust retention, fast response time, and low power consumption. This enhanced performance may be attributed to the ordered arrangement of the PbS QDs in the self-assembled PbS QDs which can efficiently guide the growth direction for the conducting filaments. Moreover, biosynaptic functions and plasticity, are implemented successfully in the MD with the self-assembled PbS QDs. This work offers a new method of improving memristor performance, which can significantly expand existing applications and facilitate the development of artificial neural systems.
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http://dx.doi.org/10.1002/adma.201805284DOI Listing
February 2019

Lead Halide Perovskite Nanostructures for Dynamic Color Display.

ACS Nano 2018 Sep 16;12(9):8847-8854. Epub 2018 Aug 16.

State Key Laboratory on Tunable Laser Technology, Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System , Shenzhen Graduate School, Harbin Institute of Technology , Shenzhen 518055 , China.

Nanoprint-based color display using either extrinsic structural colors or intrinsic emission colors is a rapidly emerging research field for high-density information storage. Nevertheless, advanced applications, e. g., dynamic full-color display and secure information encryption, call for demanding requirements on in situ color change, nonvacuum operation, prompt response, and favorable reusability. By transplanting the concept of electrical/chemical doping in the semiconductor industry, we demonstrate an in situ reversible color nanoprinting paradigm via photon doping, triggered by the interplay of structural colors and photon emission of lead halide perovskite gratings. It solves the aforementioned challenges at one go. By controlling the pumping light, the synergy between interlaced mechanisms enables color tuning over a large range with a transition time on the nanosecond scale in a nonvacuum environment. Our design presents a promising realization of in situ dynamic color nanoprinting and will empower the advances in structural color and classified nanoprinting.
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http://dx.doi.org/10.1021/acsnano.8b02425DOI Listing
September 2018

Dark-Field Sensors based on Organometallic Halide Perovskite Microlasers.

Adv Mater 2018 Aug 26;30(32):e1801481. Epub 2018 Jun 26.

State Key Laboratory on Tunable laser Technology, Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, 518055, P. R. China.

The detection of nanoscale objects is essential for homeland security, environmental monitoring, and early-stage diagnostics. In the past few years, optical sensors have mostly been developed with passive devices such as microcavity and plasmonic nanostructures, which require external laser sources to operate and significantly increase the costs and bulks of sensing systems. To date, the potential of their active counterparts in optical sensors has not been well explored. Herein, a novel and robust mechanism to detect nanoscale objects with lead halide perovskite microlasers is demonstrated. Nanoparticles can be simply detected and sized by measuring the intensity of scattered laser light. In principle, the proposed concept is also applicable to electrically driven microlasers and it could find applications in portable point-of-care devices.
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http://dx.doi.org/10.1002/adma.201801481DOI Listing
August 2018

Formation of Lead Halide Perovskite Based Plasmonic Nanolasers and Nanolaser Arrays by Tailoring the Substrate.

ACS Nano 2018 04 16;12(4):3865-3874. Epub 2018 Apr 16.

State Key Laboratory on Tunable Laser Technology, Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Shenzhen Graduate School , Harbin Institute of Technology , Shenzhen 518055 , China.

Hybrid plasmonic nanolasers are intensively studied due to their nanoscale mode confinement and potentials in highly integrated photonic and quantum devices. Until now, the characteristics of plasmonic nanolasers are mostly determined by the crystal facets of top semiconductors, such as ZnO nanowires or nanoplates. As a result, the spasers are isolated, and their lasing wavelengths are random and difficult to tune. Herein, we experimentally demonstrate the formation of lead halide perovskite (MAPbX) based hybrid plasmonic nanolasers and nanolaser arrays with arbitrary cavity shapes and controllable lasing wavelengths. These spasers are composed of MAPbX perovskite nanosheets, which are separated from Au patterns with a 10 nm SiO spacer. In contrast to previous reports, here, the spasers are determined by the boundary of Au patterns instead of the crystal facets of MAPbX nanosheets. As a result, whispering gallery mode based circular spasers and spaser arrays were successfully realized by patterning the Au substrate into circles and gratings, respectively. The standard wavelength deviation of spaser arrays is as small as 0.3 nm. Meanwhile, owing to the anion-exchangeable property of MAPbX perovskite, the emission wavelengths of spasers were tuned more than 100 nm back and forth by changing the stoichiometry of perovskite postsynthetically.
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http://dx.doi.org/10.1021/acsnano.8b01206DOI Listing
April 2018