Gambogic acid(GA), a caged xanthone derivative isolated from Garcinia Hanburyi, exhibits significant antitumor activity and has advanced to phase Ⅱ clinical trials for lung cancer treatment in China. However, the clinical application of GA is severely hindered by its inherent limitations, including poor water solubility, a lack of targeting specificity, and significant side effects. Novel drug delivery systems not only overcome these pharmacological deficiencies but also integrate multiple therapeutic modalities, transcending the limitations of monotherapeutic approaches. In this study, we designed a multifunctional nanodelivery platform(PDA-PEG-Fe(Ⅲ)-GOx-GA) using polydopamine(PDA) as the core material. After the modification of PDA with polyethylene glycol(PEG), Fe(Ⅲ) ions, glucose oxidase(GOx), and GA were sequentially loaded via coordination interactions, electrostatic adsorption, and hydrophobic interactions, respectively. This system demonstrated excellent physiological stability, hemocompatibility, and photothermal conversion efficiency. Notably, under dual stimuli of pH and near-infrared(NIR) irradiation, PDA-PEG-Fe(Ⅲ)-GOx-GA achieved controlled GA release, with a cumulative release rate of 58.3% at 12 h, 3.6-fold higher than that under non-stimulated conditions. Under NIR irradiation, the synergistic effects of PDA-mediated photothermal therapy, Fe(Ⅲ)-induced chemodynamic therapy, GOx-generated starvation therapy, and GA-mediated chemotherapy resulted in effective inhibition of tumor cell proliferation(91.5% inhibition rate) and induction of apoptosis(83.3% apoptosis rate). This multi-modal approach realized a comprehensive treatment strategy for lung cancer, integrating various therapeutic pathways.
Xanthones/pharmacology* ; Humans ; Polymers/chemistry* ; Glucose Oxidase/pharmacology* ; Indoles/chemistry* ; Drug Delivery Systems ; Drug Carriers/chemistry* ; Nanoparticles/chemistry* ; Cell Line, Tumor

Glucose oxidase (GOD) is an oxygen-consuming dehydrogenase that can catalyze the production of gluconic acid hydrogen peroxide from glucose, and its specific mechanism of action makes it promising for applications, while the low catalytic activity and poor thermostability have become the main factors limiting the industrial application of this enzyme. In this study, we used the glucose oxidase AtGOD reported with the best thermostability as the source sequence for phylogenetic analysis to obtain the GOD with excellent performance. Six genes were screened and successfully synthesized for functional validation. Among them, the glucose oxidase AhGODB derived from Aspergillus heteromorphus was expressed in Pichia pastoris and showed better thermostability and catalytic activity, with an optimal temperature of 40 ℃, a specific activity of 112.2 U/mg, and a relative activity of 47% after 5 min of treatment at 70 ℃. To improve its activity and thermal stability, we constructed several mutants by directed evolution combined with rational design. Compared with the original enzyme, the mutant T72R/A153P showcased the optimum temperature increasing from 40 to 50 ℃, the specific activity increasing from 112.2 U/mg to 166.1 U/mg, and the relative activity after treatment at 70 ℃ for 30 min increasing from 0% to 33%. In conclusion, the glucose oxidase mutants obtained in this study have improved catalytic activity and thermostability, and have potential for application.
Glucose Oxidase/chemistry* ; Enzyme Stability ; Aspergillus/genetics* ; Pichia/metabolism* ; Temperature ; Catalysis ; Fungal Proteins/metabolism* ; Hot Temperature

In this study, insulin (insulin, INS)/Ca₃PO₄ complex and glucose oxidase (glucose oxidase, GOx)/Cu₃(PO₄)₂ complex were prepared by coprecipitation method. The mineralized insulin (mineralized insulin, m-INS) showed irregular crystalline clusters, and the mineralized glucose oxidase (m-GOx) showed flower spherical morphology, with a diameter of about 1-2 μm. In vitro simulated release experiment showed that m-INS released INS as the pH value of the medium decreased. When the pH value was 4.5, the release amount reached 96.68%. The enzyme activity detection experiment showed that the enzyme activity stability of m-GOx was higher than that of free GOx. It still maintained high activity after 10 days at room temperature, while the activity of GOx was less than 60%. The glucose solution was prepared to simulate the state of normal blood glucose (5.6 mmol/L) and hyperglycemia (22.2 mmol/L). When m-INS and m-GOx were added to the glucose solution, the release amount of INS showed a significant glucose concentration dependence. The higher the glucose concentration, the greater the release amount and release rate of INS. Finally, m-INS, m-GOx and hyaluronic acid (HA) solution were mixed to prepare HA microneedle arrays loaded with m-INS and m-GOx. Type 1 diabetes mice were constructed to evaluate the effect of drug-loaded HA microarray on blood glucose control in diabetic rats. The results show that the HA microneedles loaded with m-INS/m-GOx could deliver drugs effectively. The average blood glucose concentration in diabetic rats dropped to about 7 mmol/L within 1 h, normal blood glucose concentration could be maintained for 10 h, and the overall blood glucose concentration was lower than the level before administration for 36 hours. Compared with HA microneedles loaded with INS only, m-ins microneedles showed better glucose tolerance, longer-lasting glucose control effect and less risk of hypoglycemia. Compared with other sustained-release systems, the preparation process of the core components in this study is simple, efficient, safe and effective, and has great commercial potential.
Animals ; Blood Glucose ; Delayed-Action Preparations/therapeutic use* ; Diabetes Mellitus, Experimental/drug therapy* ; Drug Delivery Systems/methods* ; Glucose Oxidase/chemistry* ; Hyaluronic Acid ; I Blood-Group System ; Insulin/therapeutic use* ; Mice ; P Blood-Group System ; Rats

We studied the effect of calcium ion on particle size and pore structure of cross-linked enzyme aggregates (CLEAs) of glucose oxidase, with activity and stability of the enzyme as evaluation criteria. With calcium ion to prepare CLEA significantly decreased particle sizes of CLEAs whilst the pore structures of CLEAs gradually disappeared with the increase of calcium concentration. When glucose oxidase was precipitated at 0.1 mmol/L Ca²⁺, glucose oxidase in CLEA showed the definitive pore structure. Moreover, glucose oxidase activity in CLEA with Ca²⁺ was 1.69 times higher than that without Ca²⁺. Even at Ca²⁺ as high as 1.0 mmol/L, glucose oxidase activity in CLEA was 42% higher than that of CLEA without Ca²⁺. Furthermore, CLEA prepared with 0.1 mmol/L Ca²⁺ not only exhibited higher substrate conversion and operational stability, but also increased the maximum reaction speed. Therefore, calcium ion improved the performance of glucose oxidase in CLEAs.
Calcium ; chemistry ; Cross-Linking Reagents ; Enzyme Stability ; Enzymes, Immobilized ; Glucose Oxidase ; chemistry ; Oxidation-Reduction ; Particle Size

BACKGROUND: We evaluated the analytical performance of Barozen H (i-SENS Inc., Korea), a new glucometer equipped with networking function for medical institutions, according to the ISO 15197:2003 and ISO/DIS 15197:2011 guidelines. METHODS: We measured the precision of 10 Barozen H glucometers, in terms of repeatability and intermediate precision, and determined their accuracy relative to that of automatic chemistry analyzer AU5421 (Beckman Coulter, USA). Three other glucometers-Precision PCx (Abbott, USA), Glucocard Sigma (Arkray, Japan), and SureStep Flexx (Johnson & Johnson, USA) were also evaluated, and their accuracies and hematocrit interferences were compared. RESULTS: The standard deviation and coefficient of variation of Barozen H for repeatability and intermediate precision were 0.11-0.15 mmol/L and 2.3-3.6%, respectively. With respect to accuracy, in accordance with ISO 15197:2003 criteria, Barozen H yielded 98.0% of results within +/-0.83 mmol/L or +/-20%. Further, per the ISO/DIS 15197:2011 criteria, 95.2% of results were within +/-0.83 mmol/L or +/-15%; Barozen H was the only glucometer satisfying the more stringent ISO/DIS 15197:2011 criteria. Error grid analysis showed that all results from Barozen H were in zone A, indicating its excellent clinical accuracy. Hematocrit, ranging from 20% to 60% did not cause any significant interference. CONCLUSIONS: Barozen H showed excellent analytical performance, and it was the most clinically accurate glucometer tested. It can be expected to provide reliable results satisfying ISO/DIS 15197:2011 as well as ISO 15197:2003 criteria.
Blood Glucose Self-Monitoring ; Blood Glucose* ; Chemistry ; Diabetes Mellitus ; Glucose Oxidase ; Hematocrit ; Point-of-Care Systems

BACKGROUND: We evaluated the analytical performance of Barozen H (i-SENS Inc., Korea), a new glucometer equipped with networking function for medical institutions, according to the ISO 15197:2003 and ISO/DIS 15197:2011 guidelines. METHODS: We measured the precision of 10 Barozen H glucometers, in terms of repeatability and intermediate precision, and determined their accuracy relative to that of automatic chemistry analyzer AU5421 (Beckman Coulter, USA). Three other glucometers-Precision PCx (Abbott, USA), Glucocard Sigma (Arkray, Japan), and SureStep Flexx (Johnson & Johnson, USA) were also evaluated, and their accuracies and hematocrit interferences were compared. RESULTS: The standard deviation and coefficient of variation of Barozen H for repeatability and intermediate precision were 0.11-0.15 mmol/L and 2.3-3.6%, respectively. With respect to accuracy, in accordance with ISO 15197:2003 criteria, Barozen H yielded 98.0% of results within +/-0.83 mmol/L or +/-20%. Further, per the ISO/DIS 15197:2011 criteria, 95.2% of results were within +/-0.83 mmol/L or +/-15%; Barozen H was the only glucometer satisfying the more stringent ISO/DIS 15197:2011 criteria. Error grid analysis showed that all results from Barozen H were in zone A, indicating its excellent clinical accuracy. Hematocrit, ranging from 20% to 60% did not cause any significant interference. CONCLUSIONS: Barozen H showed excellent analytical performance, and it was the most clinically accurate glucometer tested. It can be expected to provide reliable results satisfying ISO/DIS 15197:2011 as well as ISO 15197:2003 criteria.
Blood Glucose Self-Monitoring ; Blood Glucose* ; Chemistry ; Diabetes Mellitus ; Glucose Oxidase ; Hematocrit ; Point-of-Care Systems

Conducting polymers have stable long-chain structure and good electrical conductivity. They have been used in various types of biosensors because of their excellent characteristics of the immobilization and electrical signal transmission. In recent years, researchers mainly study on improving its micro-nano structures and its signal conductivity to enhance its effect on the enzyme immobilization and signal conductive properties. This paper reviews firstly the application of conducting polymer on enzyme-immobilized glucose biosensor and the new technologies and methods in this field. This paper also points out the future application of conducting polymers in enzyme immobilization and biosensor preparation areas.
Biosensing Techniques ; methods ; trends ; Blood Glucose ; metabolism ; Electric Conductivity ; Enzymes, Immobilized ; Glucose Oxidase ; metabolism ; Nanostructures ; Polymers ; chemistry

Activity losing during the covalent immobilization of enzyme is a serious problem. Here we studied organic phase immobilization by using glucose oxidase (GOD) as a model. After lyophilized at optimum pH, GOD is covalently immobilized onto glutaraldhyde-activated chitosan microsphere carrier under the condition of water, 1, 4-dioxane, ether and ethanol separately. The special activities, enzyme characterization and kinetic parameters are determined. Results show that all of the organic phase immobilized GODs have higher special activities and larger K(cat) than that of aqueous phase. Under the conditions of 0.1% of glutaraldehyde, 1.6% moisture content with 80 mg of GOD added to per gram of carrier, 2.9-fold of the special activity and 3-fold of the effective activity recovery ratio were obtained, and 3-fold of the residue activity was demonstrated after 7 runs when compares 1, 4-dioxane phase immobilized GOD with water phase immobilized one. In addition, kinetic study shows that 1,4-dioxane immobilized GOD (Km(app) = 5.63 mmol/L, V(max) = 1.70 micromol/(min x mg GOD), K(cat) = 0.304 s(-1) was superior to water immobilized GOD (Km(app) = 7.33 mmol/L, V(max) = 1.02 micromol/(min x mg GOD), K(cat) = 0.221 s(-1)). All above indicated GOD immobilized in proper organic media presented a better activity with improved catalytic performance. Organic phase immobilization might be one of the ways to overcome the conformational denature of enzyme protein during covalent modification.
Chitosan ; chemistry ; Dioxanes ; chemistry ; Enzymes, Immobilized ; chemistry ; Freeze Drying ; Glucose Oxidase ; chemistry ; Kinetics ; Microspheres