Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

Objective:To investigate the protective effect of a composite hydrogel against hydrogen peroxide(H2O2)-induced oxidative stress injury in the cardiomyocytes,and to clarify its possible mechanism.Methods:The mice were subcutaneously injected with 100 μL of hydrogel.After normal feeding for 1,14,and 28 d,the mice were sacrificed.Tissue samples were collected and subjected to HE staining to observe the histocompatibity of the hydrogel.The primary cardiomyocytes isolated from 1-day-old SD rats were used to establish an oxidative stress injury model.The primary cardiomyocyties were divided into control,H2O2 and H2O2+Hydrogel groups.The primary cardiomyocytes in control group were cultured normally,the primary cardiomyocytes in H2O2 group were treated with 200 μmol·L-1 H2O2 for 24 h,and the primary cardiomyocytes in H2O2+Hydrogel group were incubated with 1 g·L-1 composite hydrogel and 200 μmol·L-1 H2O2 for 24 h.The viabilities of cardiomyocytes in various groups were assessed by cell counting kit-8(CCK-8)method.Dihydroethidium(DHE)and 2',7'-dichlorodihydrofluorescein diacetate(DCFH-DA)staining were used to assess the reactive oxygen species(ROS)levels in the cells.The expressions of filamentous actin(F-actin)in the cells in various groups were detected by phalloidin fluorescence staining;the expressions of connexin 43(Cx43)and cardiac troponin T(cTnT)proteins in the cardiomyocytes in various groups were detected by immunofluorescence method.The apoptotic rates of cardiomyocytes in various groups were assessed with TUNEL staining method.The expression levels of apoptosis-related proteins B-cell lymphoma-2(Bcl-2)and Bcl-2-associated X protein(Bax)in the cardiomyocytes in various groups were assessed by Western blotting method.Results:The HE staining results showed that the inflammatory cells around the implanted hydrogel were less infiltrated,and the inflammatory reaction of subcutaneous implantation was less.Compared with control group,the viability of cardiomyocytes in H2O2 group was significantly decreased(P＜0.05),the level of ROS in the cells was increased(P＜0.05),the expression levels of Cx43,cTnT and F-actin proteins in the cells were decreased(P＜0.001),the apoptosis rate of cardiomyocytes were decreased(P＜0.01),the expression level of Bcl-2 protein in the cells was increased(P＜0.001),and the expression level of Bax protein was decreased(P＜0.01).Compared with H2O2 group,the viability of cardiomyocytes was significantly increased(P＜0.05),the level of ROS in the cells was decreased(P＜0.01),the expression levels of cTnT,Cx43 and F-actin proteins were increased(P＜0.01),the apoptotic rate of cardiomyocytes were significantly decreased(P＜0.001),the expression level of Bcl-2 protein in the cells were decreased(P＜0.01),and the expression level of Bax protein was increased(P＜0.01).Conclusion:Hydrogel may promote the expression of cardiomyocyte-related proteins by scavenging ROS in the environment and inhibit the cardiomyocyte apoptosis to achieve the protective effect on the cardiomyocytes under oxidative stress.

Poly(lactic-co-glycolide)(PLGA)is a key excipient in long-acting sustained-release preparations,and its degradation properties directly affect the drug release behavior.In this study,PLGA microspheres were prepared by microfluidic techniques,and the morphology changes of the microspheres were observed by scanning electron microscopy(SEM).In alkaline environment,due to the accelerated hydrolysis of ester bonds,the surface of the microspheres was rapidly dissolved and eroded,and the degradation rate was significantly higher than that in acidic environment.High temperature accelerated the degradation of PLGA microspheres.Under neutral and alkaline conditions,the microspheres showed aggregation and adhesion.Under acidic conditions,the microspheres gradually decomposed into irregular fragments.The high ionic strength further promoted the surface corrosion of the microspheres,especially under extreme pH conditions.Simultaneously,PLGA microspheres encapsulating coumarin were prepared to simulate the microsphere formulation.The release rate of coumarin after degradation of the microspheres under different conditions was observed by measuring the absorbance with ultraviolet-visible spectrophotometry.The results were consistent with those of the blank microspheres.This study revealed that the degradation of PLGA microspheres was significantly pH-dependent,temperature sensitive and ion strength responsive.These findings not only helped to understand and optimize the long-term stability and controlled release performance of drug-carrying microspheres,but also provided a theoretical basis for further improvement of PLGA-based drug carrier design.

Introducing fingerprint level 3 features(especially sweat pores)in fingerprint recognition can significantly improve the value of fingerprints.However,conventional fingerprint visualization methods suffer from issues such as poor stability and reproducibility,insufficient resolution,and feature masking in detecting level 3 features.Electrospun membrane has unique advantages in latent fingerprint(LFP)detection due to its excellent adsorption performance and high specific surface area,and thus its application potential in LFP visualization urgently need to be explored.A novel pore visualization method based on core-shell structured PAN-Flu/PVP composite nanofibrous membrane was proposed in this work.Specifically,the PAN-Flu/PVP composite nanofibrous membrane was prepared via coaxial electrospinning technology,with polyacrylonitrile(PAN)loaded with fluorescein(Flu)as the core and polyvinylpyrrolidone(PVP)as the shell.The experimental results showed that the prepared PAN Flu/PVP composite nanofibrous membrane had a porous structure and excellent adsorption performance.Based on the water solubility of the outer shell PVP and the water induced fluorescence enhancement effect of the core Flu,high-resolution visualization of sweat pores could be achieved within 2 s.The optimization experiment showed that the best quality of sweat latent fingerprints was obtained when the Flu content was 4 mg/mL,the spinning time was 1 h,and the sweating time was 2 min.Through repeated fingerprinting and live fingerprint comparison experiment,the strong stability and high reproducibility of the as-produced membrane in displaying fingerprint sweat pores were finally verified.In summary,the development method could quickly,stably and accurately extract the spatial distribution and activity level of fingerprint sweat pores,which was of great significance for improving the utilization and value of fingerprints.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective To summarize the changing prevalence of carbapenem resistance in Enterobacterales based on the data of CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021 for improving antimicrobial treatment in clinical practice.Methods Antimicrobial susceptibility testing was performed using a commercial automated susceptibility testing system according to the unified CHINET protocol.The results were interpreted according to the breakpoints of the Clinical & Laboratory Standards Institute(CLSI)M100 31st ed in 2021.Results Over the seven-year period(2015-2021),the overall prevalence of carbapenem-resistant Enterobacterales(CRE)was 9.43％(62 342/661 235).The prevalence of CRE strains in Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae was 22.38％,9.73％,and 8.47％,respectively.The prevalence of CRE strains in Escherichia coli was 1.99％.A few CRE strains were also identified in Salmonella and Shigella.The CRE strains were mainly isolated from respiratory specimens(44.23±2.80)％,followed by blood(20.88±3.40)％and urine(18.40±3.45)％.Intensive care units(ICUs)were the major source of the CRE strains(27.43±5.20)％.CRE strains were resistant to all the β-lactam antibiotics tested and most non-β-lactam antimicrobial agents.The CRE strains were relatively susceptible to tigecycline and polymyxins with low resistance rates.Conclusions The prevalence of CRE strains was increasing from 2015 to 2021.CRE strains were highly resistant to most of the antibacterial drugs used in clinical practice.Clinicians should prescribe antimicrobial agents rationally.Hospitals should strengthen antibiotic stewardship in key clinical settings such as ICUs,and take effective infection control measures to curb CRE outbreak and epidemic in hospitals.

Objective To characterize the changing species distribution and antibiotic resistance profiles of respiratory isolates in hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Commercial automated antimicrobial susceptibility testing systems and disk diffusion method were used to test the susceptibility of respiratory bacterial isolates to antimicrobial agents following the standardized technical protocol established by the CHINET program.Results A total of 589 746 respiratory isolates were collected from 2015 to 2021.Overall,82.6％of the isolates were Gram-negative bacteria and 17.4％were Gram-positive bacteria.The bacterial isolates from outpatients and inpatients accounted for(6.0±0.9)％and(94.0±0.1)％,respectively.The top microorganisms were Klebsiella spp.,Acinetobacter spp.,Pseudomonas aeruginosa,Staphylococcus aureus,Haemophilus spp.,Stenotrophomonas maltophilia,Escherichia coli,and Streptococcus pneumoniae.Each microorganism was isolated from significantly more males than from females(P＜0.05).The overall prevalence of methicillin-resistant S.aureus(MRSA)was 39.9％.The prevalence of penicillin-resistant S.pneumoniae was 1.4％.The prevalence of extended-spectrum β-lactamase(ESBL)-producing E.coli and K.pneumoniae was 67.8％and 41.3％,respectively.The overall prevalence of carbapenem-resistant E.coli,K.pneumoniae,Enterobacter cloacae,Pseudomonas aeruginosa,and Acinetobacter baumannii was 3.7％,20.8％,9.4％,29.8％,and 73.3％,respectively.The prevalence of β-lactamase was 96.1％in Moraxella catarrhalis and 60.0％in Haemophilus influenzae.The H.influenzae isolates from children(＜18 years)showed significantly higher resistance rates to β-lactam antibiotics than the isolates from adults(P＜0.05).Conclusions Gram-negative bacteria are still predominant in respiratory isolates associated with serious antibiotic resistance.Antimicrobial resistance surveillance should be strengthened in clinical practice to support accurate etiological diagnosis and appropriate antimicrobial therapy based on antimicrobial susceptibility testing results.

Metabolic dysfunction-associated steatotic liver disease (MASLD), the most prevalent chronic liver condition globally, lacks adequate and effective therapeutic remedies in clinical practice. Recent studies have increasingly highlighted the close connection between the ubiquitin-proteasome system (UPS) and the progression of MASLD. This relationship is crucial for understanding the disease's underlying mechanism. As a sophisticated process, the UPS govern protein stability and function, maintaining protein homeostasis, thus influencing a multitude of elements and biological events of eukaryotic cells. It comprises four enzyme families, namely, ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), ubiquitin-protein ligases (E3), and deubiquitinating enzymes (DUBs). This review aims to delve into the array of pathways and therapeutic targets implicated in the ubiquitination within the pathogenesis of MASLD. Therefore, this review unveils the role of ubiquitination in MASLD while spotlighting potential therapeutic targets within the context of this disease.

Objective To develop the "Questionnaires on the Knowledge, Attitudes, and Practices of College Students in Response to Public Health Emergencies" and validate its reliability and validity. Methods The initial questionnaire was developed according to literature review, expert consultations, and one-on-one interviews with students and educators. A total of 43 college students were selected as the pre-test subjects using the convenience sampling method. The final version of the questionnaire was developed using item analysis and expert consultations. A total of 682 college students were selected as the validation subjects using the cluster sampling method. The exploratory factor analysis and confirmatory factor analysis were used to assess the reliability and validity of the questionnaire. Results The final version of the questionnaire consisted of three dimensions: knowledge, practice, and attitude, with 5, 10, 7 items, respectively. The KMO test value for the questionnaire was 0.804, with Bartlett′s test of sphericity showing a chi-square value of 2 000.557 (P<0.01). The content validity index for each item ranged from 0.894 to 1.000, with the overall content validity index for the questionnaire being 0.966 and 0.973. The exploratory factor analysis identified three common factors, with a cumulative variance contribution rate of 54.1%. The result of confirmatory factor analysis showed good model fit, with model fit index, comparative fit index, normed fit index, incremental fit index, Tucker-Lewis Index, root mean square error of approximation of 2.960, 0.930, 0.940, 0.930, 0.950 and 0.070, respectively. The Cronbach's α coefficient for the questionnaire was 0.772, split-half reliability was 0.604, and test-retest reliability was 0.905. Conclusion The "Questionnaires on the Knowledge, Attitudes, and Practices of College Students in Response to Public Health Emergencies" demonstrates good reliability, and it is suitable for widespread application.

Objective:To evaluate the safety and clinical efficacy of enteral nutrition (EN) initiated within 24 h after heart transplantation in pediatric patients.Methods:A retrospective cohort study was conducted. Clinical data from 16 pediatric heart transplant recipients at the Seventh Medical Center of the Chinese People′s Liberation Army General Hospital between October 2022 and October 2024 were collected, including demographics, anthropometric measurements, biochemical markers, cytokine levels, and clinical outcomes. Based on the timing of EN initiation, the patients were divided into EN-initiated within 24 h and EN-initiated after 24 h 2 groups. Demographic data, preoperative extracorporeal membrane oxygenation (ECMO) support, physical examination indicators, laboratory parameters, and cytokine levels were compared between groups using independent samples t-test, Mann-Whitney U test, Fisher′s exact probability test. Results:The cohort comprised 16 patients (10 males and 6 females) with an age of (12.5±1.9) years. The EN-initiated within 24 h group comprised 6 cases, and the EN-initiated after 24 h group comprised 10 cases. No significant difference was observed between the two groups in age, preoperative body mass index Z-score, preoperative ECMO support, physical examination indicators, laboratory parameters (total protein, albumin, hemoglobin), or cytokine levels (all P>0.05). Compared to the EN-initiated after 24 h group, the EN-initiated within 24 h group exhibited a shorter intensive care unit stay ( t=2.65, P<0.05) and shorter mechanical ventilation duration ( t=2.23, P<0.05) than EN-initiated after 24 h group. Total hospitalization length had no significant difference ( P>0.05). At 72 h post-transplant, the EN-initiated within 24 h group had a lower interleukin-12 P70 ( t=2.46, P<0.05) and interferon-γ levels ( t=2.55, P<0.05) than EN-initiated after 24 h group. Prior to discharge, the EN-initiated within 24 h group has a lower mean skinfold thickness ( t=2.49, P<0.05) and lower mid-upper arm circumference ( t=2.36, P<0.05) compared with the EN-initiated after 24 h group. Conclusions:Initiating EN within 24 h postoperatively is safe and feasible in pediatric heart transplant recipients. Early EN may shorten the length of intensive care unit stay and mechanical ventilation while attenuating postoperative release of inflammatory cytokine.