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Biomedical subjects

Zhenyu Sun

Publications and source records attributed to Zhenyu Sun.

17 recordsLinked to original sources
PubMed2026

Proteomic Identification of Pig Xenoantigens for Clinical Xenotransplantation.

Xenotransplantation using genetically engineered pig organs offers a promising solution to the shortage of donor organs for life-saving transplantations. However, human-preformed antibodies against unknown pig xenoantigens remain a significant barrier to successful xenotransplantation. Current methods for characterizing these antibodies or xenoantigens are limited to cellular-level cross-match assays. In this study, we developed a novel approach to identify pig xenoantigens, including peptide and glycopeptide epitopes, that react with human-preformed antibodies. First, human-preformed antibodies against xenoantigens were enriched from plasma using immobilized pig kidney proteins. The enriched antibodies were then immobilized and used to isolate pig kidney proteins, peptides, and intact glycopeptides, followed by liquid chromatography-tandem mass spectrometry analysis. This dual-level approach identified 221 peptides corresponding to 153 proteins, with a significant enrichment of plasma membrane and extracellular proteins. Notably, 11 peptides were unique to pig sequences, suggesting their potential role in driving xenogeneic immune responses. Glycoproteomic analysis identified 122 intact glycopeptides, predominantly complex/hybrid glycoforms, and Neu5Gc-containing glycans. Our method effectively identifies peptides and intact glycopeptides reactive to human-preformed antibodies, providing critical insights for discovering xenoantigens. These findings could guide genetic engineering strategies and enhance recipient candidate screening for xenotransplantation, ultimately increasing the feasibility and success of xenogeneic organ transplantation.

Animals↗
PubMed2025

Multi-omic profiling of intraductal papillary neoplasms of the pancreas reveals distinct patterns and potential markers of progression.

To enable early detection of pancreatic cancer from precancerous lesions, we analyze proteins and glycoproteins from 64 intraductal papillary mucinous neoplasms (IPMNs), 55 cyst fluid samples, 104 pancreatic ductal adenocarcinomas (PDACs), and various types of normal samples using mass spectrometry. High-grade IPMNs show enrichment of glycosylation level and tumor progression pathways compared to low-grade lesions. High-grade IPMN associated proteins, such as PLOD3, IRS2, LGALS9, and Trop-2, are identified and validated using immunolabeling and laser microdissection. Some high-grade associated proteins are also detected in pancreatic cyst fluids, which allows us to link proteins and glycoproteins expressed in neoplastic cells to clinically accessible biospecimens. Altered glycosylation level of extracellular matrix (ECM) proteins is observed in IPMNs compared to normal ducts. Additionally, we identify a subset of IPMNs with PDAC-like features, including elevated expression of ECM proteins. These findings offer insight into progression-associated proteins and emphasize the diagnostic and therapeutic potential of these proteins in pancreatic tumors.

Humans↗
PubMed2006

Decoration carbon nanotubes with Pd and Ru nanocrystals via an inorganic reaction route in supercritical carbon dioxide-methanol solution.

This work describes a method to decorate carbon nanotubes (CNTs) with metallic Pd and Ru nanocrystals via inorganic reactions in supercritical (SC) CO2-methanol solutions. In this route, PdCl2 or RuCl3.3H2O dissolved in SC CO2-methanol solution acted as a metal precursor and CNTs functioned as a template to direct the deposition of produced nanoparticles. Methanol served as the reductant for the precursors as well as cosolvent to enhance the dissolution of precursors in SC CO2. Dry products were readily obtained through in situ extraction with SC CO2 after reactions. The products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. It was demonstrated that the loading content and particle size of the nanoparticles deposited on CNTs could be tuned by changing the weight ratio of the precursor to CNTs. This simple and efficient approach may also be utilized to synthesize other high-purity materials using inorganic salt precursors in SC CO2-based solution.

Journal Article↗
PubMed2006

Synthesis of ZrO2-carbon nanotube composites and their application as chemiluminescent sensor material for ethanol.

ZrO2-carbon nanotube (CNT) composites have been successfully synthesized via decomposition of Zr(NO3)4.5H2O in supercritical carbon dioxide-ethanol solution with dispersed CNTs at relatively low temperatures. The samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) analyses. It was demonstrated that CNTs were fully coated with an amorphous ZrO2 layer, and the coating layer was nominally complete and uniform. In addition, the thickness of the coating sheath could be readily controlled by tuning the Zr(NO3)4.5H2O/CNTs ratio used. Furthermore, the chemiluminescent sensor prepared from ZrO2-carbon nanotube composites exhibited dramatic sensitivity as well as high stability and selectivity to ethanol.

Journal Article↗
PubMed2006

Synthesis and characterization of ZnS-montmorillonite nanocomposites and their application for degrading eosin B.

Nanocomposites of zinc sulfide (ZnS) and montmorillonite (MMT) were prepared via a hydrothermal route. In this method, the MMT treated with hexadecyltrimethyl ammonium bromide (HTAB) aqueous solution was dispersed in the aqueous solution of thiourea and Zn(OOCHCH(3))(2)2H(2)O, and heated at 170 degrees C for about 4 h, resulting in ZnS-MMT composites. The as-prepared nanocomposites were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen sorption analysis. It was demonstrated that the interlayer space of MMT was enlarged from 0.98 to 3.77 nm after the treatment with HTAB aqueous solution, and the ZnS nanoparticles were deposited on the layers of MMT. Nitrogen sorption analysis demonstrated that the specific surface area of the samples decreased from 39.2 m(2)/g of the pristine MMT to 5.9 m(2)/g of the final ZnS-MMT composites. The resulting ZnS-MMT nanocomposites (50.0 mg) could degrade eosin B completely in aqueous solution (75 ml, 3.2x10(-5) M) within 20 min under UV irradiation.

Journal Article↗
PubMed2006

Synthesis of noble metal/carbon nanotube composites in supercritical methanol.

A simple and efficient route has been employed to deposit noble metal nanoparticles (Pt, Ru, Pt-Ru, Rh, Ru-Sn) onto carbon nanotubes (CNTs) in supercritical methanol solution. In this method, the inorganic metallic salts acted as metal precursors, and methanol as solvent as well as reductant for the precursors. The as-prepared nanocomposites were structurally and morphologically characterized by X-ray diffraction spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy, and X-ray photoelectron spectroscopy analyses. It was demonstrated that the CNTs were decorated by crystalline metal nanoparticles with uniform sizes and a narrow particle size distribution. The size and loading content of the nanoparticles on CNTs could be tuned by manipulating reaction parameters. Furthermore, the formation mechanism of the composites was also discussed.

Chromatography, Supercritical Fluid↗
PubMed2006

Microwave-assisted synthesis of pt nanocrystals and deposition on carbon nanotubes in ionic liquids.

In this work, a simple, fast and efficient route is presented for the metal (such as Pt, Rh, etc.) nanocrystal synthesis and deposition on carbon nanotubes (CNTs) in ionic liquids (ILs) via microwave heating. In this method, inorganic salts (such as H2PtCl6.4H2O, RhCl3.2H2O, etc.) dissolved in ILs, 1,1,3,3-tetramethylguanidinium trifluoroacetate or 1,1,3,3-tetramethylguanidinium lactate, were reduced to metal nanoparticles by glycol with the aid of microwave heating, and the produced metal nanoparticles could be decorated on CNTs in the presence of CNTs in ILs. The resulting nanomaterials were characterized by means of transmission electron microscopy and X-ray diffraction. It was demonstrated that the homogeneously dispersed Pt nanocrystals with the size of 2-3 nm were obtained using H2PtCl6.4H2O as precursor, and they deposited on CNTs with the similar size when CNTs was present in ILs. This technique also can be extended to fabricate other noble metal nanocrystals (including Rh, Au, etc.) and corresponding CNT composites.

Carbon↗
PubMed2006

Synthesis of polyaniline nanofibrous networks with the aid of an amphiphilic ionic liquid.

In this work, polyaniline (PANI) nanofibrous networks were prepared using ionic liquid (IL), 1-hexadecyl-3-methylimidazolium chloride (C16MIMCl), as a template through oxidative polymerization of aniline with ammonium persulfate. The resulting PANI was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis, and FTIR. It was indicated that the as-prepared PANI was in the emeraldine form and its morphology strongly depended on the molar ratio of aniline/C16MIMCI. A possible mechanism for the formation of PANI nanofibrous networks was that the ordered micro-domains of the IL acted as template to direct the growth of the nanostructures.

Aniline Compounds↗
PubMed2005

Facile route to synthesize multiwalled carbon nanotube/zinc sulfide heterostructures: optical and electrical properties.

A simple method to decorate the multiwalled carbon nanotubes (MWCNTs) with ZnS nanospheres has been developed. The method involves ultrasonic pretreatment and heat treatments of MWCNTs, zinc chloride, and thiourea in ethanol. The heterostructures have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Comparative experiments show that both ultrasonic treatment and heat treatment are necessary for synthesizing the MWCNTs/ZnS heterostructures. Moreover, a photoluminescence spectrum shows that the MWCNTs/ZnS heterostructures feature a broad blue emission at about 430 nm, indicating that there exists significant ground-state interaction between ZnS nanospheres and MWCNTs. Meanwhile, the current-voltage characteristic of the MWCNTs/ZnS exhibits clear rectifying behavior, revealing charge transfer between MWCNTs and ZnS nanospheres.

Journal Article↗
PubMed2005

Replication of biological organizations through a supercritical fluid route.

A novel and simple method to replicate biological organizations (cotton and pollen grains) with high precision was proposed, in which the precursor dissolved in supercritical CO2 reacted with the surface active groups and adsorbed surface water on biological templates, followed by in situ SCF extraction of the byproducts and unreacted precursor, resulting in inorganic replicas faithfully copying both the macro- and microstructures of the biotemplates.

Carbon Dioxide↗
PubMed2005

Facile synthesis of polyaniline nanofibers using chloroaurate acid as the oxidant.

This work demonstrated a facile route to the synthesis of polyaniline (PANI) nanofibers by polymerization of aniline using chloroaurate acid (HAuCl(4)) as the oxidant. The reduction of AuCl(4)(-) is accompanied by oxidative polymerization of aniline, leading to uniform PANI nanofibers with a diameter of 35 +/- 5 nm and aggregated gold nanoparticles which can precipitate from the liquid phase during the reaction. The resultant PANI nanofibers and gold particles were characterized by means of different techniques, such as UV-vis, FTIR spectroscopy, and scanning and transmission electron microscopy methods. It is found that the gold aggregates are capped with polyaniline, and the conductivity of the fibers is around 0.16 S/cm.

Journal Article↗
PubMed2003

High accuracy genotyping directly from genomic DNA using a rolling circle amplification based assay.

BACKGROUND: Rolling circle amplification of ligated probes is a simple and sensitive means for genotyping directly from genomic DNA. SNPs and mutations are interrogated with open circle probes (OCP) that can be circularized by DNA ligase when the probe matches the genotype. An amplified detection signal is generated by exponential rolling circle amplification (ERCA) of the circularized probe. The low cost and scalability of ligation/ERCA genotyping makes it ideally suited for automated, high throughput methods. RESULTS: A retrospective study using human genomic DNA samples of known genotype was performed for four different clinically relevant mutations: Factor V Leiden, Factor II prothrombin, and two hemochromatosis mutations, C282Y and H63D. Greater than 99% accuracy was obtained genotyping genomic DNA samples from hundreds of different individuals. The combined process of ligation/ERCA was performed in a single tube and produced fluorescent signal directly from genomic DNA in less than an hour. In each assay, the probes for both normal and mutant alleles were combined in a single reaction. Multiple ERCA primers combined with a quenched-peptide nucleic acid (Q-PNA) fluorescent detection system greatly accellerated the appearance of signal. Probes designed with hairpin structures reduced misamplification. Genotyping accuracy was identical from either purified genomic DNA or genomic DNA generated using whole genome amplification (WGA). Fluorescent signal output was measured in real time and as an end point. CONCLUSIONS: Combining the optimal elements for ligation/ERCA genotyping has resulted in a highly accurate single tube assay for genotyping directly from genomic DNA samples. Accuracy exceeded 99 % for four probe sets targeting clinically relevant mutations. No genotypes were called incorrectly using either genomic DNA or whole genome amplified sample.

Chromosomes, Human, Pair 6↗
PubMed2003

Unbiased whole-genome amplification directly from clinical samples.

Preparation of genomic DNA from clinical samples is a bottleneck in genotyping and DNA sequencing analysis and is frequently limited by the amount of specimen available. We use Multiple Displacement Amplification (MDA) to amplify the whole genome 10,000-fold directly from small amounts of whole blood, dried blood, buccal cells, cultured cells, and buffy coats specimens, generating large amounts of DNA for genetic testing. Genomic DNA was evenly amplified with complete coverage and consistent representation of all genes. All 47 loci analyzed from 44 individuals were represented in the amplified DNA at between 0.5- and 3.0-fold of the copy number in the starting genomic DNA template. A high-fidelity DNA polymerase ensures accurate representation of the DNA sequence. The amplified DNA was indistinguishable from the original genomic DNA template in 5 SNP and 10 microsatellite DNA assays on three different clinical sample types for 20 individuals. Amplification of genomic DNA directly from cells is highly reproducible, eliminates the need for DNA template purification, and allows genetic testing from small clinical samples. The low amplification bias of MDA represents a dramatic technical improvement in the ability to amplify a whole genome compared with older, PCR-based methods.

Blood Cells↗
PubMed2002

Comprehensive human genome amplification using multiple displacement amplification.

Fundamental to most genetic analysis is availability of genomic DNA of adequate quality and quantity. Because DNA yield from human samples is frequently limiting, much effort has been invested in developing methods for whole genome amplification (WGA) by random or degenerate oligonucleotide-primed PCR. However, existing WGA methods like degenerate oligonucleotide-primed PCR suffer from incomplete coverage and inadequate average DNA size. We describe a method, termed multiple displacement amplification (MDA), which provides a highly uniform representation across the genome. Amplification bias among eight chromosomal loci was less than 3-fold in contrast to 4-6 orders of magnitude for PCR-based WGA methods. Average product length was >10 kb. MDA is an isothermal, strand-displacing amplification yielding about 20-30 microg product from as few as 1-10 copies of human genomic DNA. Amplification can be carried out directly from biological samples including crude whole blood and tissue culture cells. MDA-amplified human DNA is useful for several common methods of genetic analysis, including genotyping of single nucleotide polymorphisms, chromosome painting, Southern blotting and restriction fragment length polymorphism analysis, subcloning, and DNA sequencing. MDA-based WGA is a simple and reliable method that could have significant implications for genetic studies, forensics, diagnostics, and long-term sample storage.

Blotting, Southern↗
PubMed2002

Effects of repeated + Gz forces on masticatory muscles.

OBJECTIVE: To study the effects of repeated + Gz forces on masticatory muscles. METHODS: 48 male Wistar rats were randomly divided into 4 groups. Group A was normally fed. Group B was only fixed with rat-kept devices for 5 minutes. Group C was borne + 1 Gz for 5 minutes. Group D was repeatedly exposed + 10 Gz (each for 30 s, onset rate about 0.5 G/s, 5 times/d with + 1 Gz 1 minute intervals, 4 d/wk, 3 weeks in total). The histological changes of the masseter, temporal and lateral pterygoid muscles were observed. RESULTS: No abnormal changes were observed in Group A, B and C. But pathological changes could be found in group D. The wrench and deformation of muscular fibers, the dissolution of partial myofibril, the swelling of mitochondria, the reduce of hepatin from the masseter and lateral pterygoid muscles could be found. CONCLUSIONS: Repeated + Gz stresses could induce the damage of masticatory muscles in different degrees.

Animals↗