A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electroc...A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electrochemical properties of the CuO/MWCNT‐modified glassy carbon electrode were investigated. Two distinguishable anodic peaks were observed around 0.30 and 0.44 V corresponding to the oxidation of glucose and fructose, respectively, at the surface of the modified electrode. The detection limits for glucose and fructose were both 0.04 mmol/L. The sensor was used to simultaneously determine the concentrations of glucose and fructose in hydrolyzed sucrose samples, and to measure glucose in blood serum samples, demonstrating its potential as a nonenzymatic carbohydrate sensor.展开更多
A novel nonenzymatic glucose sensor was successfully fabricated based on the Cu2O polyhedrons covered Cu foil. The Cu2O polyhedrons covered Cu foil was constructed via a facile, low-cost and larger scale producible me...A novel nonenzymatic glucose sensor was successfully fabricated based on the Cu2O polyhedrons covered Cu foil. The Cu2O polyhedrons covered Cu foil was constructed via a facile, low-cost and larger scale producible method. The Cu2O polyhedrons covered Cu foil can be directly used as the working electrode of nonenzymatic glucose sensor, which present good stability and flexibility. The results indicated that the Cu2O polyhedrons modified Cu electrode （Cu2O/Cu electrode） showed high electrocatalytic activity for the oxidation of glucose in alkaline solution. There are two linear regions of glucose concentration for the glucose sensor based on Cu2O/Cu electrode, respectively in 10μmol/L to 0.53 mmol/L （sensitivity： 3029.33 μA （mmol/ L）^-1 cm^-2） and in 0.53-7.53 mmol/L （sensitivity： 728.67 μA （rnmol/L）^-1 cm^-2）.展开更多
With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aer...With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition.This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose.With the synergistic effect of three heterogeneous components,the electrode achieves outstanding glucose sensing performance,including a high sensitivity(851.4μA·mmol^(−1)·L·cm^(−2)),a short response time(2.2 s),a wide linear range(two stages:0.001−8.145 and 8.145−35.500 mmol·L^(−1)),strong immunity to interference,outstanding intraelectrode and interelectrode reproducibility,a favorable toxicity resistance(Cl^(‒)),and a good long-term stability(maintaining 86.0%of the original value after 30 d).These data are superior to those of some traditional glucose sensors using nonbiomass substrates.When determining the blood glucose level of a human serum,this electrode realizes a high recovery rate of 97.07%–98.89%,validating the potential for highperformance blood glucose sensing.展开更多
Phenylspirodrimanes are a kind of meroterpenoids with structural diversity and complexity,exhibiting a wide of biological properties,especially for the lactam derivatives consisting a y-lactam moiety and N-linked side...Phenylspirodrimanes are a kind of meroterpenoids with structural diversity and complexity,exhibiting a wide of biological properties,especially for the lactam derivatives consisting a y-lactam moiety and N-linked side chains.These compounds were derived from multi-step combination of enzymatic and non-enzymatic conversions of intermediates in their biosynthetic pathways.Stachbotrydial(2)with an o-phthalaldehyde unit was supposed as the high-reactivity intermediate of phenylspirodrimane lactams via nonenzymatic reaction with amines.In the present work,an effective and non-enzymatic diversification strategy was developed for the structural diversification of phenylspirodrimane lactams including monomers and dimers from 2 by feeding structurally various mono-and diamines in the fungus Stachybotrys chartarum cultures.In total,24 phenylspirodrimane lactams(1,3-25)including 18 new compounds were synthesized.Among them,stachybocin A(1),a bioactive phenylspirodrimane lactam dimer,was produced with the yield of 18.7 mg/g of cell dry weight.The structures of these compounds were elucidated by extensive spectroscopic data,single-crystal X-ray diffraction(Cu Kα),and calculated electronic circular dichroism(ECD)analyses.Bioassay revealed that compounds 1,17,and 24 displayed significant inhibitory effect on the inactivated state of hNav 1.2 channels with IC_(50) values of 0.22,2.08,and 0.53μmol/L,respectively.In addition,1 showed potent protein tyrosine phosphatase 1B(PTP1B)inhibitory N-methyl-b-aspartate(NMDA)receptor antagonistic,and anti-inflammatory activities.展开更多
The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper （Cu） nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose ...The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper （Cu） nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection. The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry （CV）. The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirrqed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles. The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314 μA rnM^-1 cm^-2 with linear concentration range （0.02-3.0 mM） having detection limit 10.0 μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.展开更多
[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ab...[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ability and reducing capacity of DPPH as well as inhibitory rate of nonenzymatic glycation reaction were measured targets for comparing changes of anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of fermentation lyophilizer and fermentation extraction before and after EGB fermention adsorbed by AB-8 macroporous resin. The EGB fermention was biotransformed by Hericium erinaceus. [ Result ] After adsorbed by AB-8 macroporous resin, the bioactive matters were concentrated and separated. The free radical scavenging rate, reducing capacity and inhibitory rate of nonenzymatic glycation reaction were increased significantly after adsorbed by AB-8 macroporous resin. [ Conclusion] AB-8 macroporous resin could be used for preliminary concentration of EGB fermentation which was biotransformed by Hericium erinaceus.展开更多
To study the relationship between advanced glycosylation end products (AGE) and protein kinase C (PKC), and their effects on renal alteration in diabetic rats Methods Insulin or aminoguanidine was administered to di...To study the relationship between advanced glycosylation end products (AGE) and protein kinase C (PKC), and their effects on renal alteration in diabetic rats Methods Insulin or aminoguanidine was administered to diabetic rats Blood glucose, hemoglobin A 1C (HbA 1C ), glomerular tissue extracts AGE (GTE AGE), PKC, glomerular basement membrane thickness (GBMT) and urine protein/creatinine (Pr/Cr) ratio in diabetic rats were measured and analysed Results Levels of blood glucose, HbA 1C and AGE, PKC activity, the Pr/Cr ratio and GBMT were all significantly increased ( P values all less than 0 01) in diabetic rats Insulin could decrease the formation of HbA 1C and AGE, and improve PKC activity Aminoguanidine had no influence on PKC activity ( P >0 05) although it decreased the formation of AGE Both drugs could delay the increase of urine Pr/Cr ratio and GBMT ( P <0 05 or P <0 01) Conclusions Chronic hyperglycemia may lead to an increase of PKC activity HbA 1C and AGE may not directly contribute to alterations of PKC activity, but the increase of PKC activity could promote the action of AGE on GBM thickening It is important to inhibit the formation of AGE and reduce the PKC activity so as to prevent or delay the development of diabetic nephropathy展开更多
Racemization of aspartic acid (Asp) residues in proteins plays an important role in the molecular biology of aging. In the widely accepted mechanism of the Asp racemization, a succinimide (SI) intermediate is the spec...Racemization of aspartic acid (Asp) residues in proteins plays an important role in the molecular biology of aging. In the widely accepted mechanism of the Asp racemization, a succinimide (SI) intermediate is the species which actually undergo the direct racemization. In the present study, a two-water-assisted mechanism of the SI racemization was computationally investigated using a model compound in which an aminosuccinyl (Asu) residue is capped with acetyl and NMe groups on the N-and C-termini, respectively. The two water molecules catalyze the enolization of the Hα-Cα-C=O portion in the Asu residue by mediating proton relay from the α-carbon atom to the carboxyl oxygen atom. After the enolization, migration of the water molecules and conformational change lead to the mirror image of the initially formed enol two-water complex, and the racemization is completed by the following ketonization. The overall activation barrier (28.2 kcal·mol-1) corresponds to the enolization and ketonization steps, and falls within the available experimental activation energies (21.4-29.0 kcal·mol-1). Therefore, the two-water-assisted mechanism investigated here is plausible for the in vivo and in vitro racemization reactions of the SI intermediates formed in peptides and proteins.展开更多
基金The Iranian Nanotechnology Initiative,Research Council of Isfahan University of Technology,and Centre of Excellence in Sensor and Green Chemistry
文摘A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electrochemical properties of the CuO/MWCNT‐modified glassy carbon electrode were investigated. Two distinguishable anodic peaks were observed around 0.30 and 0.44 V corresponding to the oxidation of glucose and fructose, respectively, at the surface of the modified electrode. The detection limits for glucose and fructose were both 0.04 mmol/L. The sensor was used to simultaneously determine the concentrations of glucose and fructose in hydrolyzed sucrose samples, and to measure glucose in blood serum samples, demonstrating its potential as a nonenzymatic carbohydrate sensor.
基金supported by the Universities Natural Science Foundation of Jiangsu Province (No. 11KJB480001)Postdoctoral Foundation of Jiangsu Province (No. 1102125C)Highly Qualified Professional Initial Funding of Jiangsu University (No. 10JDG120)
文摘A novel nonenzymatic glucose sensor was successfully fabricated based on the Cu2O polyhedrons covered Cu foil. The Cu2O polyhedrons covered Cu foil was constructed via a facile, low-cost and larger scale producible method. The Cu2O polyhedrons covered Cu foil can be directly used as the working electrode of nonenzymatic glucose sensor, which present good stability and flexibility. The results indicated that the Cu2O polyhedrons modified Cu electrode （Cu2O/Cu electrode） showed high electrocatalytic activity for the oxidation of glucose in alkaline solution. There are two linear regions of glucose concentration for the glucose sensor based on Cu2O/Cu electrode, respectively in 10μmol/L to 0.53 mmol/L （sensitivity： 3029.33 μA （mmol/ L）^-1 cm^-2） and in 0.53-7.53 mmol/L （sensitivity： 728.67 μA （rnmol/L）^-1 cm^-2）.
基金supported by the National Natural Science Foundation of China(Grant No.31901249),the Hunan Provincial Natural Science Foundation of China(Grant No.2022JJ30079)the Hunan Provincial Technical Innovation Platform and Talent Program in Science and Technology(Grant No.2020RC3041)the Training Program for Excellent Young Innovators of Changsha(Grant No.kq2106056).
文摘With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition.This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose.With the synergistic effect of three heterogeneous components,the electrode achieves outstanding glucose sensing performance,including a high sensitivity(851.4μA·mmol^(−1)·L·cm^(−2)),a short response time(2.2 s),a wide linear range(two stages:0.001−8.145 and 8.145−35.500 mmol·L^(−1)),strong immunity to interference,outstanding intraelectrode and interelectrode reproducibility,a favorable toxicity resistance(Cl^(‒)),and a good long-term stability(maintaining 86.0%of the original value after 30 d).These data are superior to those of some traditional glucose sensors using nonbiomass substrates.When determining the blood glucose level of a human serum,this electrode realizes a high recovery rate of 97.07%–98.89%,validating the potential for highperformance blood glucose sensing.
基金financially supported by National Natural Science Foundation of China(No.81803403)CAMS Innovation Fund for Medical Sciences(Nos.CIFMS-2022-I2M-JB-011 and CIFMS-2021-12M-1-029).
文摘Phenylspirodrimanes are a kind of meroterpenoids with structural diversity and complexity,exhibiting a wide of biological properties,especially for the lactam derivatives consisting a y-lactam moiety and N-linked side chains.These compounds were derived from multi-step combination of enzymatic and non-enzymatic conversions of intermediates in their biosynthetic pathways.Stachbotrydial(2)with an o-phthalaldehyde unit was supposed as the high-reactivity intermediate of phenylspirodrimane lactams via nonenzymatic reaction with amines.In the present work,an effective and non-enzymatic diversification strategy was developed for the structural diversification of phenylspirodrimane lactams including monomers and dimers from 2 by feeding structurally various mono-and diamines in the fungus Stachybotrys chartarum cultures.In total,24 phenylspirodrimane lactams(1,3-25)including 18 new compounds were synthesized.Among them,stachybocin A(1),a bioactive phenylspirodrimane lactam dimer,was produced with the yield of 18.7 mg/g of cell dry weight.The structures of these compounds were elucidated by extensive spectroscopic data,single-crystal X-ray diffraction(Cu Kα),and calculated electronic circular dichroism(ECD)analyses.Bioassay revealed that compounds 1,17,and 24 displayed significant inhibitory effect on the inactivated state of hNav 1.2 channels with IC_(50) values of 0.22,2.08,and 0.53μmol/L,respectively.In addition,1 showed potent protein tyrosine phosphatase 1B(PTP1B)inhibitory N-methyl-b-aspartate(NMDA)receptor antagonistic,and anti-inflammatory activities.
基金supported by the University of Engineering and Technology, Lahore, Pakistan
文摘The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper （Cu） nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection. The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry （CV）. The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirrqed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles. The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314 μA rnM^-1 cm^-2 with linear concentration range （0.02-3.0 mM） having detection limit 10.0 μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.
基金the Natural Science Foundation of Jiangsu Province (BK2003047)~~
文摘[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ability and reducing capacity of DPPH as well as inhibitory rate of nonenzymatic glycation reaction were measured targets for comparing changes of anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of fermentation lyophilizer and fermentation extraction before and after EGB fermention adsorbed by AB-8 macroporous resin. The EGB fermention was biotransformed by Hericium erinaceus. [ Result ] After adsorbed by AB-8 macroporous resin, the bioactive matters were concentrated and separated. The free radical scavenging rate, reducing capacity and inhibitory rate of nonenzymatic glycation reaction were increased significantly after adsorbed by AB-8 macroporous resin. [ Conclusion] AB-8 macroporous resin could be used for preliminary concentration of EGB fermentation which was biotransformed by Hericium erinaceus.
文摘To study the relationship between advanced glycosylation end products (AGE) and protein kinase C (PKC), and their effects on renal alteration in diabetic rats Methods Insulin or aminoguanidine was administered to diabetic rats Blood glucose, hemoglobin A 1C (HbA 1C ), glomerular tissue extracts AGE (GTE AGE), PKC, glomerular basement membrane thickness (GBMT) and urine protein/creatinine (Pr/Cr) ratio in diabetic rats were measured and analysed Results Levels of blood glucose, HbA 1C and AGE, PKC activity, the Pr/Cr ratio and GBMT were all significantly increased ( P values all less than 0 01) in diabetic rats Insulin could decrease the formation of HbA 1C and AGE, and improve PKC activity Aminoguanidine had no influence on PKC activity ( P >0 05) although it decreased the formation of AGE Both drugs could delay the increase of urine Pr/Cr ratio and GBMT ( P <0 05 or P <0 01) Conclusions Chronic hyperglycemia may lead to an increase of PKC activity HbA 1C and AGE may not directly contribute to alterations of PKC activity, but the increase of PKC activity could promote the action of AGE on GBM thickening It is important to inhibit the formation of AGE and reduce the PKC activity so as to prevent or delay the development of diabetic nephropathy
文摘Racemization of aspartic acid (Asp) residues in proteins plays an important role in the molecular biology of aging. In the widely accepted mechanism of the Asp racemization, a succinimide (SI) intermediate is the species which actually undergo the direct racemization. In the present study, a two-water-assisted mechanism of the SI racemization was computationally investigated using a model compound in which an aminosuccinyl (Asu) residue is capped with acetyl and NMe groups on the N-and C-termini, respectively. The two water molecules catalyze the enolization of the Hα-Cα-C=O portion in the Asu residue by mediating proton relay from the α-carbon atom to the carboxyl oxygen atom. After the enolization, migration of the water molecules and conformational change lead to the mirror image of the initially formed enol two-water complex, and the racemization is completed by the following ketonization. The overall activation barrier (28.2 kcal·mol-1) corresponds to the enolization and ketonization steps, and falls within the available experimental activation energies (21.4-29.0 kcal·mol-1). Therefore, the two-water-assisted mechanism investigated here is plausible for the in vivo and in vitro racemization reactions of the SI intermediates formed in peptides and proteins.
