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Biomedical subjects

Bing Shao

Publications and source records attributed to Bing Shao.

At least 19 recordsLinked to original sources
PubMed2026

Emergence of an optrA-positive Enterococcus faecalis ST699 lineage in animal-derived foods in Beijing, China.

Enterococci from animal-derived foods are key reservoirs for antimicrobial resistance (AMR) in the food chain. However, comparative genomic studies investigating the distribution of the oxazolidinone resistance gene optrA among food- and human-derived Enterococci remain limited. This study assessed linezolid-resistant Enterococci from retail meat and healthy humans in Beijing, China (2023-2024). Among 87 isolates, E. faecalis and E. faecium predominated. Food-derived isolates showed broader resistance profiles than human isolates. Fourteen optrA-positive strains were identified, accounting for 92.9% of food isolates. optrA frequently co-localized with erm(A), ant(9)-Ia, and fexA on Tn554-family transposons, suggesting a potentially transferable multidrug resistance module. Notably, an optrA-positive E. faecalis ST699 clone was identified for the first time in Chinese retail meat. This clone formed a distinct lineage and carried a complete Tn554-optrA island. A representative ST699 isolate exhibited enhanced fitness and virulence potential in the Galleria mellonella model. These findings highlight animal-derived foods as important reservoirs of linezolid-resistant Enterococci and provide genomic evidence consistent with their role as potential sources of optrA-mediated resistance. The emergence of a multidrug-resistant E. faecalis ST699 clone with enhanced fitness characteristics underscores the need for continued surveillance of foodborne antimicrobial resistance within the One Health framework.

Enterococcus faecalis↗
PubMed2025

Fluorinated Ionizable Lipids for Efficient Spleen-Targeted mRNA Delivery in Cancer Immunotherapy.

Efficient and selective mRNA delivery to immune-related organs, particularly the spleen, remains a major barrier to the broader clinical translation of mRNA therapeutics. Here, leveraging the clinically approved SM-102/ALC-0315 ionizable lipid scaffold, we rationally designed a combinatorial library of fluorinated ionizable lipids (FILs) by systematically modulating hydrophobic tails and fluorine stoichiometry. Through synthesis and evaluation of 74 candidate FILs, we identify SSC6F5 lipid nanoparticles (LNPs) as a lead formulation with exceptional spleen-targeting specificity (>90%) across intravenous, intramuscular, and subcutaneous administrations. Compared to clinically approved SM102 LNPs and spleen-tropic SM102/18PA (SORT) LNPs, intravenously administered SSC6F5 LNPs achieve 10.6-fold and 63.1-fold higher splenic mRNA transfection, respectively. Proteomic analysis of protein corona on SSC6F5 LNPs reveals significant enrichment of apolipoprotein D (Apod) and reduction in apolipoprotein H (Apoh), implicating a novel endogenous recognition pathway driving enhanced spleen targeting. Functionally, SSC6F5 LNPs enable efficient genome editing in splenic macrophages, dendritic cells, T cells, and B cells in Ai9 mice, and elicit potent CD8+ T cell and humoral responses in a B16-OVA murine melanoma model, resulting in significant tumor growth inhibition. These findings establish fluorinated lipids as a mechanistically distinct and translationally versatile platform for precision spleen-targeted mRNA delivery in gene editing and cancer immunotherapy.

Animals↗
PubMed2007

High-throughput sorting and analysis of human sperm with a ring-shaped laser trap.

Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dynamically monitor changes in sperm swimming behavior under the influence of a laser beam. Here, we report a continuous 3-D ring-shaped laser trap which could be used for multi-level and high-throughput (tens to hundred sperm per ring) sperm sorting based on their motility and chemotaxis. Under a laser power of only tens of milliWatts, human sperm with low to medium velocity are slowed down, stopped, or forced to change their trajectories to swim along the ring due to the optical gradient force in the radial direction. This is the first demonstration of parallel sperm sorting based on motility with optical trapping technology. In addition, by making the sperm swimming along the circumference of the ring, the effect of laser radiation, optical force and external obstacles on sperm energetics are investigated in a more gentle and quantitative way. The application of this method could be extended to motility and bio-tropism studies of other self-propelled cells, such as algae and bacteria.

Cell Separation↗
PubMed2006

Size tunable three-dimensional annular laser trap based on axicons.

A three-dimensional (3D) ring-shaped laser trap has been built using axicons. The diameter of this laser trap ranges from 70 to 140 mum and is adjusted by simply changing the position of one axicon in the optical path. Parallel 3D trapping of 5 mum silica microspheres and 3D confinement of cells along the ring are demonstrated. In this system the special optical properties of axicons are used to create a continuous annular trap with high power efficiency and a constant numerical aperture. This new approach, without any mechanical scanning, offers significant potential for applications in cell motility analysis and biotropism studies.

Equipment Design↗
PubMed2006

Dynamically adjustable annular laser trapping based on axicons.

To study the chemotactic response of sperm to an egg and to characterize sperm motility, an annular laser trap based on axicons is designed, simulated with the ray-tracing tool, and implemented. The diameter of the trapping ring can be adjusted dynamically for a range of over 400 microm by simply translating one axicon along the optical axis. Trapping experiments with microspheres and dog sperm demonstrate the feasibility of the system, and the power requirement agrees with theoretical expectation. This new type of laser trapping could provide a prototype of a parallel, objective, and quantitative tool for animal fertility and biotropism study.

Animals↗
PubMed2006

Simultaneous determination of seventeen glucocorticoids residues in milk and eggs by ultra-performance liquid chromatography/electrospray tandem mass spectrometry.

A comprehensive analytical method has been developed and validated for the simultaneous determination of seventeen glucocorticoid residues in eggs and milk. The mass spectrometer parameters, the composition of the mobile phase and the sample preparation method were firstly optimized to obtain maximum sensitivity. The samples were deconjugated with beta-glucuronidase/arylsulfatase enzyme and concentrated using an Oasis HLB solid-phase extraction cartridge, followed by cleanup with a dual Sep-pak silica and aminopropyl cartridge. The analytes were quantified by ultra-performance liquid chromatography (using a C18 column)/electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) operating in the negative ion mode. The assay for the 17 glucocorticoids was linear over the range of 1-200 microg/L for milk and egg samples with a high correlation coefficient (>0.99). The limits of quantification (LOQs) for the target analytes were 0.04-1.27 microg/kg for the egg samples and 0.03-0.73 microg/kg for the milk samples. The average extraction recoveries of the glucocorticoids from eggs and milk at two concentration levels (spiked at 0.40 and 2.00 microg/kg) were 65.6-118.7% and 61.5-119.6%, respectively, with relative standard deviations between 1.8-17.0% and 2.4-18.4%, respectively. Because of its high sensitivity, good precision and specificity, the method was found to be suitable for trace analysis of synthetic and natural glucocorticoids in complex biosamples such as eggs and milk.

Animals↗
PubMed2006

[Simultaneous determination of twelve glucocorticoids residues in milk by ultra performance liquid chromatography-electrospray tandem mass spectrometry].

A comprehensive analytical method based on ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS) with negative mode has been developed for the simultaneous determination of twelve glucocorticoids residues in milk. The multi-reaction monitoring mode was employed for the determination. Milk samples were extracted by sonication in a methanol/acetate buffer (pH 5.20) solution, and then defatted with n-hexane. Sample concentration and purification were performed using Oasis HLB, Sep-pak silica and Sep-pak amino-propyl solid phase extraction cartridges. The separation was performed on a Waters ACQUITY UPLC BEH C18 column (100 mm x 1.0 mm i. d., 1.7 microm) with gradient elution using methanol and water (containing 0.1% formic acid) at a flow rate of 0.1 mL/min. Identification of the glucocorticoids was done using retention times and the distribution of diagnostic ion pairs. Quantification of the glucocorticoids was based on the peak areas of the parent ion and a fragment ion with a higher signal. The limits of detection (LOD) of the method were from 0.02 to 0.38 microg/kg and the limits of quantification (LOQ) ranged from 0.07 to 1.27 microg/kg. Average recoveries for the twelve glucocorticoids (spiked at the levels of 2 and 0.4 microg/kg) ranged from 69.3% to 94.3%, with relative standard deviations between 3.5% and 16.7%. Routine tests showed that the method is fast, sensitive and specific for the determination of glucocorticoids residues in milk.

Animals↗
PubMed2005

Counter-propagating optical trapping system for size and refractive index measurement of microparticles.

We propose and demonstrate a novel approach to measure the size and refractive index of microparticles based on two beam optical trapping, where forward scattered light is detected to give information about the particle. The counter-propagating optical trap measurement (COTM) system exploits the capability of optical traps to measure pico-Newton forces for microparticles' refractive index and size characterization. Different from the current best technique for microparticles' refractive index measurement, refractometry, a bulk technique requiring changing the fluid composition of the sample, our optical trap technique works with any transparent fluid and enables single particle analysis without the use of biological markers. A ray-optics model is used to explore the physical operation of the COTM system, predict system performance and aid system design. Experiments demonstrate the accuracy of refractive index measurement of Deltan=0.013 and size measurement of 3% of diameter with 2% standard deviation. Present performance is instrumentation limited, and a potential improvement by more than two orders of magnitude can be expected in the future. With further development in parallelism and miniaturization, the system offers advantages for cell manipulation and bioanalysis compatible with lab-on-a-chip systems.

Biopolymers↗
PubMed2005

Nonylphenol and nonylphenol ethoxylates in river water, drinking water,and fish tissues in the area of Chongqing, China.

Little attention has been paid to the estrogenic-like compounds, such as 4-nonylphenol (4-NP) and its potential precursor nonylphenol ethoxylates (NPEOs), in China although its usage is huge. Water samples and corresponding drinking water samples were seasonally collected at five sites of each of the two main rivers in Chongqing Area. Individual nonylphenol ethoxylates (NPEOs) and 4-NP in the Changjiang River and Jialingjiang River were detected by normal-phase liquid chromatography electrospray ionization mass spectrometry and gas chromatography-mass spectrometry. The results indicated that of the five sampling points in the two rivers, NPEOs were the dominant pollutant in April and December with the similar distribution profile, and total NPEOs with different ethylene oxide lengths were 6.9-97.6 microg/L in April and 2.5-52.7 microg/L in December. However, NP was the dominant pollutant in July with a concentration of 1.7-7.3 microg/L. Corresponding drinking water samples derived from river water as source suggested that the conventional water treatment process used in the five waterworks could remove NPEOs from the source water with high removal efficiency (>99%). The 4-NP removal efficiency, however, varied in a range of 62% to 95%, leaving a significantly high concentration of NP (0.1 to 2.7 microg/L) in drinking water in July. Fish samples taken in December 2000 contained 4-NP of approximately 1.9 microg/g and NPEOs of 0.4-48.3 microg/g, with the highest concentration level found in liver.

Animals↗
PubMed2005

Two-beam optical traps: refractive index and size measurements of microscale objects.

A counter-propagating optical trap measurement (COTM) system is proposed and analyzed based on the ray-optics model. In this system, refractive index and size of trapped objects can be estimated by using forward scattered light from the two-beam laser trap with resolution Delta n = 0.013 for the refractive index measurements and 3.3% for the size measurements, which is comparable with current bulk techniques, such as refractometry, and flow cytometry. The unique advantage of the COTM system over conventional approaches lies in its capability of marker-free single-particle characterization in whatever transparent buffer required by living cell, eliminating the necessity of changing the fluid composition of the sample in refractometry, and of tagging target with toxic fluorescence dyes in flow cytometry. Noise analysis predicts a potential improvement in the system resolution by more than two orders of magnitude. This non-invasive and sterile tool complements lab-on-a-chips with single cell manipulation and analysis in living friendly ambient.

Biopolymers↗
PubMed2005

[Determination of estrogen-like compounds in beverages by high performance liquid chromatography].

A comprehensive analytical method based on high performance liquid chromatography-ultraviolet-fluorescence detection (HPLC-UV-FL) has been established for the determination of bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP) in beverages with different samples and concentrations. Clean-up of samples was performed on an OASIS HLB solid extraction cartridges (6 mL, 200 mg). The method was successfully applied to the investigation of residual bisphenol A, nonylphenol and octylphenol in the beverages (mineral waters and soft drinks) available in commercial markets in Beijing. Recoveries for bisphenol A, nonylphenol and octylphenol at different spiked levels were ranged from 91.08% to 103.19% with relative standard deviations of 0.5% to 5.49%. The method is simple with good reproducibility and selectivity, and high sensitivity.

Beverages↗
PubMed2005

[Determination of acrylamide in heated starchy food by liquid chromatography-electrospray ionization tandem mass spectrometry].

An isotope dilution liquid chromatographic-electrospray ionization tandem mass spectrometric method has been established for the determination of acrylamide in heated starchy food with a C18 analytical column and methanol-water containing 0.1% formic acid (2:98, v/v) as mobile phases. The clean-up of samples was performed on an Oasis HLB solid phase extraction cartridge. The calibration curve of acrylamide showed good linearity in the range of 10-500 microg/L with correlation coefficient of 0.9995. The detection limit of the method was 6 microg/kg (S/N = 3), and the limit of quantification was 20 microg/kg (S/N = 10). The average recoveries at three levels ranged from 96.8% to 97.4% (n = 5), and the relative standard derivations were lower than 10%.

Acrylamide↗
PubMed2005

[Analysis of nonylphenol, octylphenol and bisphenol A in animal tissues by liquid chromatography-tandem mass spectrometry with accelerated solvent extraction].

A comprehensive analytical method based on liquid chromatography-electrospray ionization tandem mass spectrometry with negative ionization mode has been developed for measuring alkylphenols (AP) and bisphenol A (BPA) in animal tissues. Samples of animal tissues were extracted by accelerated solvent extraction with dichloromethane. Sample concentration and purification were performed using an OASIS NH2 solid extraction cartridge. The effects of mobile phase and additives on ionization were assessed. The recoveries for the compounds ranged from 88% to 101% and the relative standard deviations were below 15%. The detection limits of the method under multiple-reaction monitoring mode were 0.3, 0.05 and 0.1 microg/kg for BPA, nonylphenol (NP) and octylphenol (OP), respectively. The contents of NP ranging from 0.49 to 55.98 microg/kg were found in 27 real samples of animal tissues from Beijing market. The results indicate that the endocrine disrupting nonylphenol is ubiquitous in food of animal origin. Nonylphenol was found in all fish samples with concentration levels ranging from 9. 13 to 55.98 microg/kg.

Animals↗
PubMed2005

[Simultaneous determination of seventeen sulfonamide residues in chickens by liquid chromatography-electrospray tandem mass spectrometry].

A liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of seventeen commonly used sulfonamide (SA) residues in chickens has been developed. Stable isotopic compound (13)C6-sulfamethazine was used as internal standard. Multi-reaction monitoring mode was employed for the quantitative determination. The separation was performed on a Capcell Pak C8 DD column (150 mm x 2.0 mm i.d., 5 microm) with a gradient system of water (containing 0.2% formic acid)-methanol (containing 0.2% formic acid) as mobile phase at a flow rate of 0.2 mL/min. Samples were prepared by homogenizing the chicken, extracting with acetonitrile, defatting with n-hexane and cleaning-up with Sep-Pak Silica solid-phase extraction. The detection limits of 0.02 - 1 microg/kg proved to be much better than the previously reported ones. Average recoveries of seventeen SAs ( spiked at the levels of 1, 5, 10 microg/kg) ranged from 52.3% to 124.9%, with relative standard deviations between 1.0% and 17.6%. Intra-day and inter-day variations of the method were all with in the acceptable ranges. The results demonstrated that the method is simple, accurate and suitable for the identification and quantification of these sulfonamide residues in chickens.

Animals↗
PubMed2004

Indirect identification of isoprenoid quinones in Escherichia coli by LC-MS with atmospheric pressure chemical ionization in negative mode.

A novel analytical method was applied for identification of isoprenoid quinones in Escherichia coli by liquid chromatography atmospheric press chemical ionization mass spectrometry in negative mode (LC-NI-APCI-MS). Extraction and clean-up of sample were carried out on Sep-Pak Plus Silica solid-phase extraction cartridges. Ubiquinone-7 (UQ-7), Ubiquinone-8 (UQ-8) and Mequinone-8 (MK-8) were determined directly using combined information on retention time, molecular ion mass, fragment ion masses and UV characteristic spectrometry without any standard reagent. It was found that UQ-8 was the major component of isoprenoid quinones in Escherichia coli under aerobic condition. Compared with UQ-8, the relative abundance of UQ-7 and MK-8 is only 15% and 14%, respectively. The average recoveries of UQ-6, UQ-10 and vitamin K(1) in Escherichia coli were investigated by standard spiking experiment. The recoveries were achieved in the range from 94 to 106%, and the relative standard deviations (RSD) of the triplicate analysis of the spiked samples (UQ-6, UQ-10 and vitamin K(1)) ranged from 3 to 8%. The detection limits of LC-NI-APCI-MS were estimated to be 5, 40 and 0.8 microg/g dry cell for UQ-6, UQ-10 and vitamin K(1), respectively.

Chromatography, Liquid↗
PubMed2003

Identification of ubiquinones and menaquinones in activated sludge by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A sensitive analytical method has been developed for identification of ubiquinones (UQ-n(Hx)) and menaquinones (MK-n(Hx)) in activated sludge by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-NI-APCI-MS). Extraction and clean-up of samples were carried out on Sep-Pak Plus Silica solid-phase extraction cartridges. Complete separation of quinones was achieved with an ODS analytical column and using isopropyl ether-methanol (17:83, v/v) as the mobile phase. The compositions of ubiquinones and menaquinones were determined directly using combined information on retention time, the molecular ion mass and fragment ion masses. The lowest instrument quantitative detection limits (LODinst) for UQ-6, UQ-10, and Vitamin K1 were estimated to be 0.4, 4 and 0.12 ng (S/N = 10) using LC-NI-APCI-MS in SIM mode, and the lowest method detection limits (LODmeth) achieved by spiking experiment were estimated to be 0.2, 2 and 0.06 microg/g for UQ-6, UQ-10 and Vitamin K1, respectively. On the other hand, the LODinst for UQ-6, UQ-10, and Vitamin K1 were estimated to be 10, 100 and 2 ng (S/N = 10) using LC-NI-APCI-MS in full-scan mode, and the LODmeth were estimated to be 7, 60 and 1.2 microg/g for UQ-6, UQ-10, and Vitamin K1, respectively. Both LC-NI-APCI-MS and LC-UV/DAD were applied in the analysis of an activated sludge extract. UQ-n (n = 6-10), MK-n (n = 6-10), MK-n(H2) (n = 7-10), MK-n(H4) (n = 8-9) and MK-8(H6) were detected by LC-NI-APCI-MS, while UQ-6, UQ-7, MK-7(H), MK-9 and MK-10(H2) were not found by LC-UV/DAD. These results suggest that LC-NI-APCI-MS is more sensitive than LC-UV/DAD for the analysis of quinones in environmental samples such as sediment, activated sludge and bio-film in biological processes and other aquatic environments.

Atmospheric Pressure↗