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.

Lung cancer poses a serious threat to global public health security.Chemotherapy,as the main strategy for cancer treatment,faces challenges such as high toxicity and drug resistance.Anticancer peptides have the potential of being developed into new anticancer drugs due to their advantages of broad-spectrum anticancer activity,rapid action,and difficulty in generating drug resistance,but they also face shortcomings such as weak activity and strong toxic side effects.The weakly acidic microenvironment of tumors(pH 6.5-6.8)provides a good idea for the design of anticancer peptides of high-efficiency and low-toxicity.Previously,we designed the acid-sensitive antibacterial peptide pHly-1 using the wolf spider(Lycosa singoriensis)toxin Lycosin-Ⅰ as a template.In this study,we found that pHly-1 also had acid-sensitive anticancer activity.Further alanine scanning analysis of pHly-1 was carried out,and we ob-tained a mutant pHTP-2 with better acid sensitivity,whose IC50(half maximal inhibitory concentration)against A549 cells was 15.68 μmol/L at pH 6.6 and was greater than 100 μmol/L at pH 7.4.At pH 6.6,pHTP-2 could act on various lung cancer cell lines and induce the death of A549 cells by rapid ly-sis;at pH 7.4,500 μmol/L pHTP-2 had weak toxicity to red blood cells(the hemolysis rate was ap-proximately 38％)and primary myocardial cells(the inhibition rate was 49.7％,with P＜0.05).Analy-sis of its charge,particle size,morphology,and secondary structure showed that at pH 6.6,the histidine in the sequence of pHTP-2 was protonated,increasing the positive charge(P＜0.01),decreasing the hy-drated particle size(P＜0.05)and forming an α-helical structure to induce membrane lysis of A549 cells.At pH 7.4,it was deprotonated,the positive charge decreases,a β-sheet structure was formed and self-aggregation occurred,limiting its effect on the A549 cell membrane and showing weak activity.In summary,pHTP-2 could respond to the weakly acidic microenvironment of tumors to exert selective cyto-toxic activity,effectively overcoming the shortcomings of anticancer peptides such as low efficiency and high toxicity.Our findings suggest that it is a high-quality lead molecule for anticancer drugs.

Objective:To explore the impact of plant and animal dietary behaviors on type 2 diabetes mellitus (T2DM) in older adults aged ≥65 in 18 longevity areas of China.Methods:The subjects were 5 223 older adults over 65 years old from the Healthy Ageing and Biomarkers Cohort Study (HABCS) in 18 longevity areas in China. Through a questionnaire survey and physical examination, information about their demographic characteristics, lifestyles, daily activities, self-health status, current diseases, and fasting venous blood were collected. Food Frequency and Questionnaire (FFQ) was used to collect data on food intake frequency. Based on the prior method, the plant-based diet index (PDI) and animal-based diet index (ADI) of 5 223 older adults were calculated. Subjects were divided into three groups (low-level group: PDI<39 or ADI<31, middle-level group: 39≤PDI≤42 or 31≤ADI≤34, high-level group: PDI>42 or ADI>34) by tertiles of PDI and ADI. Multivariate logistic regression was used to analyze the association between PDI and ADI and the risk of T2DM.Results:The average age of 5 223 subjects was (84.8±11.5) years, with the median ( Q1, Q3) of PDI about 41(38, 43) and the median ( Q1, Q3) of ADI about 33 (30, 35). The prevalence rate of T2DM was 16.41% (857/5 223). After adjusting for covariates, multivariate logistic regression showed that PDI was negatively associated with T2DM. Compared with the low-level group, the OR (95% CI) for T2DM in the high-level group was 0.83 (0.69-0.99). ADI was positively associated with T2DM, and compared with the low-level group, the OR (95% CI) for T2DM in the high-level group was 1.28 (1.06-1.55). For every one-point increase in PDI and ADI, the risk of T2DM decreased by 2% and increased by 3%, respectively, with the OR (95% CI) of 0.98 (0.96-1.00) and 1.03 (1.01-1.06), respectively. Conclusion:In Chinese older adults ≥65 years in 18 longevity areas, higher adherence to the plant-based behavior may be negatively associated with the risk of T2DM, while higher adherence to the animal-based behavior may be positively associated with the risk of T2DM.

Objective:To investigate the effect of Yiqi Shengqing Formula on neuronal damage in ischemic stroke(IS)rats by regulating brain-derived neurotrophic factor(BDNF)-extracellular regulated protein kinase(ERK)-cyclic adenosine monophosphate-responsive element binding protein(CREB)signal pathway.Methods:IS rat model was prepared by modified thread suppository method,and randomly divided into model group,low dose Yiqi Shengqing Formula(3 g/kg)group,high dose Yiqi Shengqing Formula(6 g/kg)group,high dose Yiqi Shengqing Formula(6 g/kg)+empty load group,high dose Yiqi Shengqing Formula(6 g/kg)+BDNF knockdown group,with 10 rats in each group,another 10 healthy rats were set as sham operation group.After intervention with Yiqi Shengqing Formula and plasmid,neural function of rats in each group was scored with Longa scoring method;Morris water maze test was used to detect cognitive impairment of rats in each group;Nissl staining was used to detect the number of neurons in ischemic peripheral brain tissue and hippocampus of rats in each group;synaptic morphology of ischemic peripheral brain tissue was detected by silver staining;levels of TNF-α and IL-8 in brain tissue and serum of rats in each group were measured by ELISA;expressions of BDNF-ERK-CREB signal pathway related proteins in rat brain were detected by Western blot.Results:Compared with sham operation group,synaptic morphology of ischemic peripheral brain tissue in model group was severely damaged,retention time in target quad-rant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were decreased significantly(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were increased significantly(P<0.05).Compared with model group,synaptic morphological damage of ischemic peripheral brain tissue in rats in low dose Yiqi Shengqing Formula group and high dose Yiqi Shengqing Formula group was alleviated,retention time in target quadrant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were increased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were decreased(P<0.05).Compared with low dose Yiqi Shengqing Formula group,damage of synaptic morphology in ischemic peripheral brain tissue of rats in high dose Yiqi Shengqing Formula group was further alleviated,retention time in target quadrant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were further increased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were further reduced(P<0.05).Compared with high dose Yiqi Shengqing Formula group,synaptic morphological damage of ischemic peripheral brain tissue in high dose Yiqi Shengqing Formula+BDNF knockdown group was aggravated,retention time in target quadrant,times of crossing the platform,number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were decreased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were increased(P<0.05);there was no significant changes in each index of rats in high dose Yiqi Shengqing Formula+empty load group(P>0.05).Conclusion:Yiqi Shengqing Formula can inhibit the neuroinflammation of IS rats by activating BDNF-ERK-CREB signal,thereby reducing the damage of its neurons and improving its neural function.

Objective:To investigate the effect of Yiqi Shengqing Formula on neuronal damage in ischemic stroke(IS)rats by regulating brain-derived neurotrophic factor(BDNF)-extracellular regulated protein kinase(ERK)-cyclic adenosine monophosphate-responsive element binding protein(CREB)signal pathway.Methods:IS rat model was prepared by modified thread suppository method,and randomly divided into model group,low dose Yiqi Shengqing Formula(3 g/kg)group,high dose Yiqi Shengqing Formula(6 g/kg)group,high dose Yiqi Shengqing Formula(6 g/kg)+empty load group,high dose Yiqi Shengqing Formula(6 g/kg)+BDNF knockdown group,with 10 rats in each group,another 10 healthy rats were set as sham operation group.After intervention with Yiqi Shengqing Formula and plasmid,neural function of rats in each group was scored with Longa scoring method;Morris water maze test was used to detect cognitive impairment of rats in each group;Nissl staining was used to detect the number of neurons in ischemic peripheral brain tissue and hippocampus of rats in each group;synaptic morphology of ischemic peripheral brain tissue was detected by silver staining;levels of TNF-α and IL-8 in brain tissue and serum of rats in each group were measured by ELISA;expressions of BDNF-ERK-CREB signal pathway related proteins in rat brain were detected by Western blot.Results:Compared with sham operation group,synaptic morphology of ischemic peripheral brain tissue in model group was severely damaged,retention time in target quad-rant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were decreased significantly(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were increased significantly(P<0.05).Compared with model group,synaptic morphological damage of ischemic peripheral brain tissue in rats in low dose Yiqi Shengqing Formula group and high dose Yiqi Shengqing Formula group was alleviated,retention time in target quadrant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were increased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were decreased(P<0.05).Compared with low dose Yiqi Shengqing Formula group,damage of synaptic morphology in ischemic peripheral brain tissue of rats in high dose Yiqi Shengqing Formula group was further alleviated,retention time in target quadrant,times of crossing platform,the number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were further increased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were further reduced(P<0.05).Compared with high dose Yiqi Shengqing Formula group,synaptic morphological damage of ischemic peripheral brain tissue in high dose Yiqi Shengqing Formula+BDNF knockdown group was aggravated,retention time in target quadrant,times of crossing the platform,number of neurons in ischemic peripheral brain tissue and hippocampus,expressions of BDNF protein and p-ERK/ERK,p-CREB/CREB in brain tissue were decreased(P<0.05),while neurological function score and levels of inflammatory factors TNF-α and IL-8 in brain tissue and serum were increased(P<0.05);there was no significant changes in each index of rats in high dose Yiqi Shengqing Formula+empty load group(P>0.05).Conclusion:Yiqi Shengqing Formula can inhibit the neuroinflammation of IS rats by activating BDNF-ERK-CREB signal,thereby reducing the damage of its neurons and improving its neural function.

Objective To explore the predictive value of dose surface histogram(DSH)in image guided radiotherapy(IGRT)for radiotherapy-induced acute radiation proctitis(ARP)in cervical cancer(CCA).Methods Totally 380 patients with CCA IGRT admitted to some hospital from May 2019 to May 2023 were selected prospectively and randomly divided into a control group(n=1 80)and an experimental group(n=200).The patients in the 2 groups were followed up and the incidence rates of ARP were counted,and rectal dose distribution was evaluated using dose volume histogram(DVH)in the control group and DSH in the experimental group.The predictive values of DVH and DSH for ARP were evaluated and compared using ROC curves.Statistical analysis was performed using SPSS 21.0 software.Results The two groups did not have statistically significant difference in the incidence rate of ARP(P＞0.05),while there were significant differences in the evaluation indicators of the rectal dose distribution(P＜0.05).V40,V50,S40 and S50 proved to have low predictive values for grade Ⅰ-Ⅳ ARP with AUC 0.700(P＜0.05);V60 and S60 had moderate predictive values for grade Ⅰ-Ⅳ ARP with AUC greater than 0.700 and less than or equal to 0.900(P＜0.05);V70,V78,S70 and S7s showed high predictive values for grade Ⅰ-Ⅳ ARP with AUC higher than 0.900(P＜0.05).Delong's test results indicated that DVH and DSH had no significant differences in AUC when used to predict gradeⅠ-Ⅳ ARP(allP＞0.05).Conclusion DSH is essentially the same as DVH when used for the prediction of grade Ⅰ-Ⅳ ARP due to CCA IGRT,and thus can be used for the supplementation and optimization of radiotherapy planning systems.[Chinese Medical Equipment Journal,2025,46(3):48-53]

6-Thioguanine(6-TG)is an antineoplastic agent used in treatment of acute leukemia.However,significant interindividual variability in dosing regimens and frequent clinical manifestations of hepatotoxicity and myelosuppression as adverse effects have affected its therapeutic efficacy.Consequently,the development of rapid analytical methods for 6-TG in clinical samples,enabling continuous therapeutic drug monitoring of plasma concentrations,holds substantial significance in optimizing dosage regimens,mitigating adverse reactions,and investigating drug metabolism mechanisms.In this study,multi-tipped gold nanostars(AuNSs)were prepared.With bis-(p-sulfonylphenyl)phenylphosphine molecule as the protecting agent and internal standard molecule,the AuNSs were assembled onto a highly sensitive surface-enhanced Raman(SERS)substrate for developing a ratio-based SERS quantitative analysis method for 6-TG in serum.The AuNSs containing multiple tips and gaps exhibited strong local surface plasmon resonance effect and SERS activity,ensuring the sensitivity of the analytical method.Furthermore,the introduction of internal standard molecules could improve the reproducibility,which guaranteed this method suitable for rapid analysis of drug molecules in complex samples.Quantitative analysis of 6-TG was achieved with linear detetion range of 1.0×10?4-1.0 mmol/L.In the spiked recovery experiments of serum,the RSD was less than 5.32%,and the recoveries were 94%-104%,which proved that this method could be used for rapid quantitative determination of 6-TG in serum.This method provided a powerful tool for studying drug pharmacokinetics,which could promote the optimization of the usage methods of anti-cancer drugs,and it was expected to further enhance the clinical efficacy and safety of 6-TG,enabling it to achieve the best therapeutic effect.

Objective:To explore the impact of plant and animal dietary behaviors on type 2 diabetes mellitus (T2DM) in older adults aged ≥65 in 18 longevity areas of China.Methods:The subjects were 5 223 older adults over 65 years old from the Healthy Ageing and Biomarkers Cohort Study (HABCS) in 18 longevity areas in China. Through a questionnaire survey and physical examination, information about their demographic characteristics, lifestyles, daily activities, self-health status, current diseases, and fasting venous blood were collected. Food Frequency and Questionnaire (FFQ) was used to collect data on food intake frequency. Based on the prior method, the plant-based diet index (PDI) and animal-based diet index (ADI) of 5 223 older adults were calculated. Subjects were divided into three groups (low-level group: PDI<39 or ADI<31, middle-level group: 39≤PDI≤42 or 31≤ADI≤34, high-level group: PDI>42 or ADI>34) by tertiles of PDI and ADI. Multivariate logistic regression was used to analyze the association between PDI and ADI and the risk of T2DM.Results:The average age of 5 223 subjects was (84.8±11.5) years, with the median ( Q1, Q3) of PDI about 41(38, 43) and the median ( Q1, Q3) of ADI about 33 (30, 35). The prevalence rate of T2DM was 16.41% (857/5 223). After adjusting for covariates, multivariate logistic regression showed that PDI was negatively associated with T2DM. Compared with the low-level group, the OR (95% CI) for T2DM in the high-level group was 0.83 (0.69-0.99). ADI was positively associated with T2DM, and compared with the low-level group, the OR (95% CI) for T2DM in the high-level group was 1.28 (1.06-1.55). For every one-point increase in PDI and ADI, the risk of T2DM decreased by 2% and increased by 3%, respectively, with the OR (95% CI) of 0.98 (0.96-1.00) and 1.03 (1.01-1.06), respectively. Conclusion:In Chinese older adults ≥65 years in 18 longevity areas, higher adherence to the plant-based behavior may be negatively associated with the risk of T2DM, while higher adherence to the animal-based behavior may be positively associated with the risk of T2DM.

Lung cancer poses a serious threat to global public health security.Chemotherapy,as the main strategy for cancer treatment,faces challenges such as high toxicity and drug resistance.Anticancer peptides have the potential of being developed into new anticancer drugs due to their advantages of broad-spectrum anticancer activity,rapid action,and difficulty in generating drug resistance,but they also face shortcomings such as weak activity and strong toxic side effects.The weakly acidic microenvironment of tumors(pH 6.5-6.8)provides a good idea for the design of anticancer peptides of high-efficiency and low-toxicity.Previously,we designed the acid-sensitive antibacterial peptide pHly-1 using the wolf spider(Lycosa singoriensis)toxin Lycosin-Ⅰ as a template.In this study,we found that pHly-1 also had acid-sensitive anticancer activity.Further alanine scanning analysis of pHly-1 was carried out,and we ob-tained a mutant pHTP-2 with better acid sensitivity,whose IC50(half maximal inhibitory concentration)against A549 cells was 15.68 μmol/L at pH 6.6 and was greater than 100 μmol/L at pH 7.4.At pH 6.6,pHTP-2 could act on various lung cancer cell lines and induce the death of A549 cells by rapid ly-sis;at pH 7.4,500 μmol/L pHTP-2 had weak toxicity to red blood cells(the hemolysis rate was ap-proximately 38％)and primary myocardial cells(the inhibition rate was 49.7％,with P＜0.05).Analy-sis of its charge,particle size,morphology,and secondary structure showed that at pH 6.6,the histidine in the sequence of pHTP-2 was protonated,increasing the positive charge(P＜0.01),decreasing the hy-drated particle size(P＜0.05)and forming an α-helical structure to induce membrane lysis of A549 cells.At pH 7.4,it was deprotonated,the positive charge decreases,a β-sheet structure was formed and self-aggregation occurred,limiting its effect on the A549 cell membrane and showing weak activity.In summary,pHTP-2 could respond to the weakly acidic microenvironment of tumors to exert selective cyto-toxic activity,effectively overcoming the shortcomings of anticancer peptides such as low efficiency and high toxicity.Our findings suggest that it is a high-quality lead molecule for anticancer drugs.

Stroke is the main cause of death and disability among adults in China and is characterized by high incidence， disability， mortality， and recurrence rates. The combination of traditional Chinese and Western medicine has great potential in treating stroke and its sequelae. The classic traditional Chinese medicine prescription Da Chengqitang （DCQT） has a long history and proven efficacy in treating stroke. Clinically， DCQT is often used to treat stroke and its sequelae. However， the number and quality of clinical trials of DCQT in treating stroke need to be improved. Because of the insufficient basic research， the active ingredients and multi-target mechanism of action of DCQT remain unclear. Our research group has previously confirmed that DCQT can effectively reverse neurological damage， reduce iron deposition， and downregulate the levels of pro-inflammatory cytokines in the rat model of hemorrhagic stroke. The treatment mechanism is related to the nuclear factor erythroid 2-related factor 2 （Nrf2）-mediated signaling pathway and p38 mitogen-activated protein kinase （MAPK） signaling-mediated microglia activation. To clarify the pharmacodynamic basis and anti-stroke mechanism of DCQT， this article reviews the research progress in the treatment of stroke with DCQT in terms of clinical trials， pharmacodynamic material basis， safety evaluation， and mechanisms of absorbed components. This article summarizes 45 major phytochemical components of DCQT， 11 of which are currently confirmed absorbed components. Among them， emodin， rhein， chrysophanol， aloe-emodin， synephrine， hesperidin， naringin， magnolol， and honokiol can be used as quality markers （Q-markers） of DCQT. The mechanism of DCQT in treating stroke is complex， involving regulation of inflammatory responses， neuronal damage， oxidative stress， blood-brain barrier， brain-derived neurotrophic factor， and anti-platelet aggregation. This article helps to deeply understand the pharmacodynamic basis and mechanism of DCQT in treating stroke and provides a theoretical basis for the clinical application of DCQT in treating stroke and the development of stroke drugs.