Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in ...Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in water is still a challenge to hinder their practical applications.In this work,a facile strategy has been developed for aqueous synthesis of CsPbX_(3) nanocrystals,in which L-glutamic acid(LGlu)has been used to replace oleic acid in the synthetic process.Benefiting from the synergic effects of L-Glu and oleylamine(OAm),CsPbBr_(3)nanocrystals(L-Glu/OAm-CsPbBr_(3)NCs)with high water stability have been directly prepared under a mild condition at room temperature in water,facilitated by the process of crystal phase transformation from Cs_(4)PbBr_(6) to CsPbBr_(3).L-Glu/OAm-CsPbBr_(3)NCs exhibit a high quantum yield of 85%and a narrow full width at half maximum of 16 nm,demonstrating their efficient luminescence in water.Typically,L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects,improving the water stability and dispersibility of CsPbBr_(3)nanocrystals.Moreover,L-Glu/OAm-CsPbBr_(3)NCs exhibit great biocompatibility due to the presence of L-Glu,resulting in their good performance for HeLa cell imaging.Thus,we propose a facile and effective method to prepare CsPbBr_(3)nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.展开更多
L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward pr...L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward preparation of LA-based light-responsive polyesters(PLTDs)under mild conditions.PLTDs with molar masses up to 8500 g/mol and high yields exceeding 90%are obtained.The chemical structures and light-responsive self-immolative behavior of PLTDs are comprehensively characterized by employing ultraviolet-visible(UV-Vis)spectroscopy,size exclusion chromatography(SEC),nuclear magnetic resonance(NMR)spectroscopy,and liquid chromatography mass spectrometry(LC-MS).Meanwhile,monodisperse PLTD-based doxorubicin-loaded nanoparticles(PLTD-DOX-NP)(size=193 nm,PDI=0.018)are formulated by nanoprecipitation method.Upon light-induced depolymerization,the PLTD-DOX-NP undergoes rapid decomposition,resulting in a burst release of 80%cargo within 13 s.Furthermore,according to biological toxicity tests,the PLTD-NP possesses adequate biosafety,both before and after irradiation.Overall,the incorporation of P-3CP with biorenewable LA-based monomer adheres to the principles of green chemistry,significantly simplifying the synthetic pathway of light-responsive polymers.展开更多
Near-infrared spectroscopy （NIRS） with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares （PLS） r...Near-infrared spectroscopy （NIRS） with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares （PLS） regression can be used as a rapid analytical method to simultaneously quantify L-glutamic acid （L- GIu） and γ-aminobutyric acid （GABA） in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography （HPLC） reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients （R2）, root mean square error of prediction （RMSEP） and residual predictive deviation （RPD） of the external validation for the L-GIu concentration were 99.5%, 1.62 g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00 g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box- Behnken experimental design. Under the optimal conditions without pH adjustment, 200 gjL L-GIu could be catalyzed by 7148 U/L glutamate decarboxylase （GAD） to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from L-GIu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions.展开更多
The purpose of this study were to confirm whether the modified treatment with L-glutamic acid could attenuate the calcification of the GA-fixed valves and improve its biocompatibility. Pericardial valves were routinel...The purpose of this study were to confirm whether the modified treatment with L-glutamic acid could attenuate the calcification of the GA-fixed valves and improve its biocompatibility. Pericardial valves were routinely treated with GA and valves were treated with GA and 8% L-glutamic acid. The valves treated with these methods were implanted subcutaneously in rats. Calcium deposits of the valves collected at the 7th, 21st, 60th, 90th day were assessed by atomic absorption spectroscopy, and the pathologic changes were examined by light and electron microscopy. Cultured endothelial cells (ECs ) were seeded onto the valves. The cell counts were determined at the 1st. 4th, 7th, 10th day after seeding. PGI2 in culture medium was tested at the 10th day. Transmission and scanning electron microscopy were used to observe the growth of ECs on the valves.Results showed that subsequent treatment with L-glutamic acid could significantly mitigate calcification of bovine pericardial valves as compared with simple GAfixed valves (P<0. 01). ECs seeded on the GA treated valves died within 4 days.On the valves treated by modified method, ECs could proliferate and release PGI2. It is concluded that treatment with L- glutamic acid can markedly inhibit the calcification and improve the biocompatibility of bioprosthetical valves.展开更多
Chitosan/glycerophosphate thermosensitive hydrogel crosslinked physically was a potential drug delivery carrier;however, long gelation time limits its application. Here, chitosan-amino acid (AA) thermosensitive hydrog...Chitosan/glycerophosphate thermosensitive hydrogel crosslinked physically was a potential drug delivery carrier;however, long gelation time limits its application. Here, chitosan-amino acid (AA) thermosensitive hydrogels were prepared from chitosan (CS), αβ-glycerophosphate (GP), and L-lysine (Lys) or L-glutamic acid (Glu). The prepared CS-Lys/GP and CS-Glu/GP hydrogel showed good thermosensitivity and could form gels in a short time. The optimal parameters of CS-Lys/GP hydrogel were that the concentration of CS-Lys was 2.5%, the ratio of CS/Lys was 3.5/1.0, the ratio of CS-Lys/GP was 4.5/1.0. The optimal parameters of CS-Glu/GP hydrogel were that the concentration of CS-Glu was 3.0%, the ratio of CS/Glu was 2.0/1.0, and the ratio of CS-Glu/GP was 4.0/1.5. Chitosan-amino acid (CS-AA) thermosensitive hydrogel had a three-dimensional network structure. The addition of model drug tinidazole (TNZ) had no obvious effect on the structure of hydrogel. The results of infrared spectroscopy showed that there were hydrogen bonds between amino acids and chitosan. In vitro release results showed that CS-Lys/GP and CS-Glu/GP thermosensitive hydrogels had sustained release effects. Thus, the chitosan-amino acid thermosensitive hydrogels hold great potential as a sustained release drug delivery system.展开更多
The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists...The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.展开更多
[Objective]The paper was to investigate the effect of dietary supplementation of Fu-libao and L-glutamic acid on finishing and slaughter performances and meat quality trait of"L(Large Yorkshire)×L(Landrace)&...[Objective]The paper was to investigate the effect of dietary supplementation of Fu-libao and L-glutamic acid on finishing and slaughter performances and meat quality trait of"L(Large Yorkshire)×L(Landrace)"crossbred pigs.[Method]Twelve individuals of L×L crossbred pigs with similar body weight of about 51 kg were selected.The pigs were randomly divided into two groups,three replicates each group,two piglets each replicate.The pigs in control group were fed with conventional diet(control diet),and pigs in treatment group were fed with the control diet added with 0.1%Fu-libao(mainly contained soybean phospholipid)and 0.6%L-glutamic acid.All the pigs were under the same feeding conditions except for different diets during the trial.At the end of the trial,one pig with similar body weight was selected from each replicate for slaughter and determination of meat quality.[Result]Dietary supplementation of Fu-libao and L-glutamic acid had no significant impact on finishing performance of pigs between the two groups(P>0.05),but the back fat thickness of pigs in treatment group was increased(P<0.05).On the contrary,the longissimus muscle(LM)area,meat color and water-holding capacity(WHC)were reduced significantly compared with the control group(P<0.05).However,the contents of glutamic acid,glysine,alanine,threonine,proline,valine and arginine in LM were increased significantly compared with the control group(P<0.05);moreover,the total amino acid and total flavor amino acid contents in LM were increased by 5.85%(P<0.05)and 6.87%(P<0.05)respectively.In addition,the content of intramuscular fat(IMF)in LM was improved from 5.11±0.24(control group)to 8.86±0.52(treatment group)(P<0.05).[Conclusion]Although dietary supplementation of Fu-libao and L-glutamic acid did not increase the finishing and slaughter performances of L×L crossbred pigs,it significantly enhanced the contents of total amino acid,total flavor amino acid and IMF,and significantly improved meat quality.展开更多
基金support from the National Natural Science Foundation of China(Nos.22221001,and 22131007)the Science and Technology Major Plan of Gansu Province(No.23ZDGA012)the 111 project(No.B20027).
文摘Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in water is still a challenge to hinder their practical applications.In this work,a facile strategy has been developed for aqueous synthesis of CsPbX_(3) nanocrystals,in which L-glutamic acid(LGlu)has been used to replace oleic acid in the synthetic process.Benefiting from the synergic effects of L-Glu and oleylamine(OAm),CsPbBr_(3)nanocrystals(L-Glu/OAm-CsPbBr_(3)NCs)with high water stability have been directly prepared under a mild condition at room temperature in water,facilitated by the process of crystal phase transformation from Cs_(4)PbBr_(6) to CsPbBr_(3).L-Glu/OAm-CsPbBr_(3)NCs exhibit a high quantum yield of 85%and a narrow full width at half maximum of 16 nm,demonstrating their efficient luminescence in water.Typically,L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects,improving the water stability and dispersibility of CsPbBr_(3)nanocrystals.Moreover,L-Glu/OAm-CsPbBr_(3)NCs exhibit great biocompatibility due to the presence of L-Glu,resulting in their good performance for HeLa cell imaging.Thus,we propose a facile and effective method to prepare CsPbBr_(3)nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.
基金This work was financially supported by the International Science and Technology Assistance Program of the Ministry of Science and Technology(No.KY202001016)Shandong Provincial Natural Science Foundation Magnitude Fundamental Research,China(No.ZR2022ZD11)Qingdao New Energy Shandong Laboratory Open Project(No.QNESL OP202312).
文摘L-glutamic acid(LA)is a bio-based,non-toxic,environmentally friendly material derived from biomass.The present study reports the application of Passerini three-component polymerization(P-3CP)for the straightforward preparation of LA-based light-responsive polyesters(PLTDs)under mild conditions.PLTDs with molar masses up to 8500 g/mol and high yields exceeding 90%are obtained.The chemical structures and light-responsive self-immolative behavior of PLTDs are comprehensively characterized by employing ultraviolet-visible(UV-Vis)spectroscopy,size exclusion chromatography(SEC),nuclear magnetic resonance(NMR)spectroscopy,and liquid chromatography mass spectrometry(LC-MS).Meanwhile,monodisperse PLTD-based doxorubicin-loaded nanoparticles(PLTD-DOX-NP)(size=193 nm,PDI=0.018)are formulated by nanoprecipitation method.Upon light-induced depolymerization,the PLTD-DOX-NP undergoes rapid decomposition,resulting in a burst release of 80%cargo within 13 s.Furthermore,according to biological toxicity tests,the PLTD-NP possesses adequate biosafety,both before and after irradiation.Overall,the incorporation of P-3CP with biorenewable LA-based monomer adheres to the principles of green chemistry,significantly simplifying the synthetic pathway of light-responsive polymers.
基金supported by the National Natural Science Foundation of China (Nos. 81374046 and 81373506)
文摘Near-infrared spectroscopy （NIRS） with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares （PLS） regression can be used as a rapid analytical method to simultaneously quantify L-glutamic acid （L- GIu） and γ-aminobutyric acid （GABA） in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography （HPLC） reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients （R2）, root mean square error of prediction （RMSEP） and residual predictive deviation （RPD） of the external validation for the L-GIu concentration were 99.5%, 1.62 g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00 g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box- Behnken experimental design. Under the optimal conditions without pH adjustment, 200 gjL L-GIu could be catalyzed by 7148 U/L glutamate decarboxylase （GAD） to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from L-GIu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions.
文摘The purpose of this study were to confirm whether the modified treatment with L-glutamic acid could attenuate the calcification of the GA-fixed valves and improve its biocompatibility. Pericardial valves were routinely treated with GA and valves were treated with GA and 8% L-glutamic acid. The valves treated with these methods were implanted subcutaneously in rats. Calcium deposits of the valves collected at the 7th, 21st, 60th, 90th day were assessed by atomic absorption spectroscopy, and the pathologic changes were examined by light and electron microscopy. Cultured endothelial cells (ECs ) were seeded onto the valves. The cell counts were determined at the 1st. 4th, 7th, 10th day after seeding. PGI2 in culture medium was tested at the 10th day. Transmission and scanning electron microscopy were used to observe the growth of ECs on the valves.Results showed that subsequent treatment with L-glutamic acid could significantly mitigate calcification of bovine pericardial valves as compared with simple GAfixed valves (P<0. 01). ECs seeded on the GA treated valves died within 4 days.On the valves treated by modified method, ECs could proliferate and release PGI2. It is concluded that treatment with L- glutamic acid can markedly inhibit the calcification and improve the biocompatibility of bioprosthetical valves.
基金support from Natural Science Foundation of Henan Province(No.182300410213)National Natural Science Foundation of China(No.51103035).
文摘Chitosan/glycerophosphate thermosensitive hydrogel crosslinked physically was a potential drug delivery carrier;however, long gelation time limits its application. Here, chitosan-amino acid (AA) thermosensitive hydrogels were prepared from chitosan (CS), αβ-glycerophosphate (GP), and L-lysine (Lys) or L-glutamic acid (Glu). The prepared CS-Lys/GP and CS-Glu/GP hydrogel showed good thermosensitivity and could form gels in a short time. The optimal parameters of CS-Lys/GP hydrogel were that the concentration of CS-Lys was 2.5%, the ratio of CS/Lys was 3.5/1.0, the ratio of CS-Lys/GP was 4.5/1.0. The optimal parameters of CS-Glu/GP hydrogel were that the concentration of CS-Glu was 3.0%, the ratio of CS/Glu was 2.0/1.0, and the ratio of CS-Glu/GP was 4.0/1.5. Chitosan-amino acid (CS-AA) thermosensitive hydrogel had a three-dimensional network structure. The addition of model drug tinidazole (TNZ) had no obvious effect on the structure of hydrogel. The results of infrared spectroscopy showed that there were hydrogen bonds between amino acids and chitosan. In vitro release results showed that CS-Lys/GP and CS-Glu/GP thermosensitive hydrogels had sustained release effects. Thus, the chitosan-amino acid thermosensitive hydrogels hold great potential as a sustained release drug delivery system.
基金The Applied Fundamental Foundation of Jiangsu province P. R. China. Contract No BJ98041.
文摘The preparation and characterization of an immobilized L-glutamic decarboxylase (GDC) were studied. This work is to develop a sensitive method for the determination of L-glutamate using a new biosensor, which consists of an enzyme column reactor of GDC immobilized on a novel ion exchange resin (carboxymethyl-copolymer of allyl dextran and N.N?methylene-bisacrylamide CM-CADB) and ion analyzer coupled with a CO2 electrode. The conditions for the enzyme immobilization were optimized by the parameters: buffer composition and concentration, adsorption equilibration time, amount of enzyme, temperature, ionic strength and pH. The properties of the immobilized enzyme on CM-CADB were studied by investigating the initial rate of the enzyme reaction, the effect of various parameters on the immobilized GDC activity and its stability. An immobilized GDC enzyme column reactor matched with a flow injection system-ion analyzer coupled with CO2 electrode-data collection system made up the original form of the apparatus of biosensor for determining of L-glutamate acid. The limit of detection is 1.0×10-5 M. The linearity response is in the range of 5×10 -2-5×10 -5 M . The equation of linear regression of the calibration curve is y= 43.3x + 181.6 (y is the milli-volt of electrical potential response, x is the logarithm of the concentration of the substrate of L-glutamate acid). The correlation coefficient equals 0.99. The coefficient of variation equals 2.7%.
基金Major Special Project of Science and Technology Innovation-driven Development in Guangxi Province(GK AA17204052)Special Project of Basic Scientific Research Operating Expenses of Directly Affiliated Public-Interest Research Institutions in Guangxi Province(GMYK 2019-9)Special Fund Project of Central Government Guiding the Development of Local Science and Technology(GK ZY18076011).
文摘[Objective]The paper was to investigate the effect of dietary supplementation of Fu-libao and L-glutamic acid on finishing and slaughter performances and meat quality trait of"L(Large Yorkshire)×L(Landrace)"crossbred pigs.[Method]Twelve individuals of L×L crossbred pigs with similar body weight of about 51 kg were selected.The pigs were randomly divided into two groups,three replicates each group,two piglets each replicate.The pigs in control group were fed with conventional diet(control diet),and pigs in treatment group were fed with the control diet added with 0.1%Fu-libao(mainly contained soybean phospholipid)and 0.6%L-glutamic acid.All the pigs were under the same feeding conditions except for different diets during the trial.At the end of the trial,one pig with similar body weight was selected from each replicate for slaughter and determination of meat quality.[Result]Dietary supplementation of Fu-libao and L-glutamic acid had no significant impact on finishing performance of pigs between the two groups(P>0.05),but the back fat thickness of pigs in treatment group was increased(P<0.05).On the contrary,the longissimus muscle(LM)area,meat color and water-holding capacity(WHC)were reduced significantly compared with the control group(P<0.05).However,the contents of glutamic acid,glysine,alanine,threonine,proline,valine and arginine in LM were increased significantly compared with the control group(P<0.05);moreover,the total amino acid and total flavor amino acid contents in LM were increased by 5.85%(P<0.05)and 6.87%(P<0.05)respectively.In addition,the content of intramuscular fat(IMF)in LM was improved from 5.11±0.24(control group)to 8.86±0.52(treatment group)(P<0.05).[Conclusion]Although dietary supplementation of Fu-libao and L-glutamic acid did not increase the finishing and slaughter performances of L×L crossbred pigs,it significantly enhanced the contents of total amino acid,total flavor amino acid and IMF,and significantly improved meat quality.
