Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large ...Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large surface-to-volume ratio,high surface area,optical and electronic properties,high stability,easy synthesis,and tunable surface functionalization.More importantly,noble metal nanoparticles are known to have excellent compatibility with bio-materials,which is why they are widely used in biological applications.The synthesis method of noble metal nanoparticles conventionally involves the reduction of the noble metal salt precursor by toxic reaction agents such as NaBH4,hydrazine,and formaldehyde.This is a major drawback for researchers involved in biological application researches.Hence,the bio-synthesis of noble metal nanoparticles(NPs)by bio-materials via bio-reduction provides an alternative method to synthesize noble metal nanoparticles which are potentially non-toxic and safer for biological application.In this review,the bio-synthesis of noble metal nanoparticle including gold nanoparticle(AuNPs),silver nanoparticle(AgNPs),platinum nanoparticle(PtNPs),and palladium nanoparticle(PdNPs)are first discussed.This is followed by a discussion of these biosynthesized noble metal in biological applications including antimicrobial,wound healing,anticancer drug,and bioimaging.Based on these,it can be concluded that the study on bio-synthesized noble metal nanoparticles will expand further involving bio-reduction by unexplored bio-materials.However,many questions remain on the feasibility of bio-synthesized noble metal nanoparticles to replace existing methods on various biological applications.Nevertheless,the current development of the biological application by bio-synthesized noble metal NPs is still intensively ongoing,and will eventually reach the goal of full commercialization.展开更多
Glutamate decarboxylase(GAD, EC4.1.1.15) can catalyze the decarboxylation of L-glutamate to form γ-aminobutyrate(GABA), which is in great demand in some foods and pharmaceuticals. In our previous study,gad, the gene ...Glutamate decarboxylase(GAD, EC4.1.1.15) can catalyze the decarboxylation of L-glutamate to form γ-aminobutyrate(GABA), which is in great demand in some foods and pharmaceuticals. In our previous study,gad, the gene coding glutamate decarboxylase from Lactobacillus brevis CGMCC 1306, was cloned and its soluble expression was realized. In this study, error-prone PCR was conducted to improve its activity, followed by a screening. Mutant Q51 H with high activity [55.4 mmol·L-1·min-1·(mg protein)-1, 120% higher than that of the wild type at p H 4.8] was screened out from the mutant library. In order to investigate the potential role of this site in the regulation of enzymatic activity, site-directed saturation mutagenesis at site 51 was carried out,and three specific mutants, N-terminal truncated GAD, Q51 P, and Q51 L, were identified. The kinetic parameters of the three mutants and Q51 H were characterized. The results reveal that aspartic acid at site 88 and N-terminal domain are essential to the activity as well as correct folding of GAD. This study not only improves the activity of GAD, but also sheds new light on the structure–function relationship of GAD.展开更多
Biochemical reactions in vivo occur at the temperature usually lower than that in vitro,however the underlying mechanism still remains a challenge.Inspired by our recent studies of adenosine triphosphate(ATP)releasing...Biochemical reactions in vivo occur at the temperature usually lower than that in vitro,however the underlying mechanism still remains a challenge.Inspired by our recent studies of adenosine triphosphate(ATP)releasing photons to resonantly drive DNA replication in a quantum way,we propose a quantized chemical reaction driven by multiple mid-infrared(MIR)photons.The space confinement effect of enzymes on a reactant molecule increases the lifetime of excitation state of its bond vibration,providing a chance for the bond to resonantly absorb multiple photons.Although the energy of each MIR photon is significantly lower than that of chemical bond,the resonant absorption of multiple photons can break the appointed bond of confined molecules.Different from the traditional thermochemistry and photochemistry,the quantized chemical reactions could have a high energy efficiency and ultrahigh selectivity.In addition,we also suggest a quantum driving source for our quantum-confined superfluid reactions proposed previously.The quantized chemical reaction resonantly driven by multiple MIR photons holds great promise to develop novel approaches for the chemical engineering in future.展开更多
Exploitation of green chemistry approach for the synthesis of Indium Oxide nanoparticles using green synthesis has received a great attention in the field of nanotechnology. To demonstrate a biogenic method that invol...Exploitation of green chemistry approach for the synthesis of Indium Oxide nanoparticles using green synthesis has received a great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the Katira gum (Astragalus gummifer) leading to the formation of different morphological In<sub>2</sub>O<sub>3</sub> using the precursor Indium (III) Acetylacetonate and TG-DTA is characterised for calcination temperature and it is found to be above 500℃. Different techniques such as XRD, UV-VIS, SEM and EDAX have been used for the characterisation of In<sub>2</sub>O<sub>3</sub> nanoparticles. The average crystallite size of Indiumoxide nanoparticles is determined as 19 nm by using Scherrer’s Equation and PSA and studying optical properties.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.21536010).
文摘Nanomaterials are materials in which at least one of the dimensions of the particles is 100 nm and below.There are many types of nanomaterials,but noble metal nanoparticles are of interest due to their uniquely large surface-to-volume ratio,high surface area,optical and electronic properties,high stability,easy synthesis,and tunable surface functionalization.More importantly,noble metal nanoparticles are known to have excellent compatibility with bio-materials,which is why they are widely used in biological applications.The synthesis method of noble metal nanoparticles conventionally involves the reduction of the noble metal salt precursor by toxic reaction agents such as NaBH4,hydrazine,and formaldehyde.This is a major drawback for researchers involved in biological application researches.Hence,the bio-synthesis of noble metal nanoparticles(NPs)by bio-materials via bio-reduction provides an alternative method to synthesize noble metal nanoparticles which are potentially non-toxic and safer for biological application.In this review,the bio-synthesis of noble metal nanoparticle including gold nanoparticle(AuNPs),silver nanoparticle(AgNPs),platinum nanoparticle(PtNPs),and palladium nanoparticle(PdNPs)are first discussed.This is followed by a discussion of these biosynthesized noble metal in biological applications including antimicrobial,wound healing,anticancer drug,and bioimaging.Based on these,it can be concluded that the study on bio-synthesized noble metal nanoparticles will expand further involving bio-reduction by unexplored bio-materials.However,many questions remain on the feasibility of bio-synthesized noble metal nanoparticles to replace existing methods on various biological applications.Nevertheless,the current development of the biological application by bio-synthesized noble metal NPs is still intensively ongoing,and will eventually reach the goal of full commercialization.
基金Supported by the National Natural Science Foundation of China(30970638,21176220,and 31240054)the National Natural Science Foundation of Zhejiang Province(LZ13B060002)
文摘Glutamate decarboxylase(GAD, EC4.1.1.15) can catalyze the decarboxylation of L-glutamate to form γ-aminobutyrate(GABA), which is in great demand in some foods and pharmaceuticals. In our previous study,gad, the gene coding glutamate decarboxylase from Lactobacillus brevis CGMCC 1306, was cloned and its soluble expression was realized. In this study, error-prone PCR was conducted to improve its activity, followed by a screening. Mutant Q51 H with high activity [55.4 mmol·L-1·min-1·(mg protein)-1, 120% higher than that of the wild type at p H 4.8] was screened out from the mutant library. In order to investigate the potential role of this site in the regulation of enzymatic activity, site-directed saturation mutagenesis at site 51 was carried out,and three specific mutants, N-terminal truncated GAD, Q51 P, and Q51 L, were identified. The kinetic parameters of the three mutants and Q51 H were characterized. The results reveal that aspartic acid at site 88 and N-terminal domain are essential to the activity as well as correct folding of GAD. This study not only improves the activity of GAD, but also sheds new light on the structure–function relationship of GAD.
基金This work was supported by the National Key Research and Development Program of China(No.2018YFE0205501)the National Natural Science Foundation of China(Nos.21988102,51763019 and U1832125).
文摘Biochemical reactions in vivo occur at the temperature usually lower than that in vitro,however the underlying mechanism still remains a challenge.Inspired by our recent studies of adenosine triphosphate(ATP)releasing photons to resonantly drive DNA replication in a quantum way,we propose a quantized chemical reaction driven by multiple mid-infrared(MIR)photons.The space confinement effect of enzymes on a reactant molecule increases the lifetime of excitation state of its bond vibration,providing a chance for the bond to resonantly absorb multiple photons.Although the energy of each MIR photon is significantly lower than that of chemical bond,the resonant absorption of multiple photons can break the appointed bond of confined molecules.Different from the traditional thermochemistry and photochemistry,the quantized chemical reactions could have a high energy efficiency and ultrahigh selectivity.In addition,we also suggest a quantum driving source for our quantum-confined superfluid reactions proposed previously.The quantized chemical reaction resonantly driven by multiple MIR photons holds great promise to develop novel approaches for the chemical engineering in future.
文摘Exploitation of green chemistry approach for the synthesis of Indium Oxide nanoparticles using green synthesis has received a great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the Katira gum (Astragalus gummifer) leading to the formation of different morphological In<sub>2</sub>O<sub>3</sub> using the precursor Indium (III) Acetylacetonate and TG-DTA is characterised for calcination temperature and it is found to be above 500℃. Different techniques such as XRD, UV-VIS, SEM and EDAX have been used for the characterisation of In<sub>2</sub>O<sub>3</sub> nanoparticles. The average crystallite size of Indiumoxide nanoparticles is determined as 19 nm by using Scherrer’s Equation and PSA and studying optical properties.
