DNA Testing Based On Varirty Of Nanomaterials And The Catalytic Reduction Studies Of Nitrophenols

First,a localized surface plasmon resonance light-scattering strategy to study the effect of [Cu?dppz??L-Ser?]NO₃·H₂O on the stabilization of triplex DNA based on unmodified gold-nanoparticles?AuNPs?has been described,depended on the similar means,a novel localized surface plasmon resonance light scattering strategy for sensitive detection of silver ions?Ag⁺?and L-cysteine?Cys?was studied based on triplex-functionalized gold nanoparticle in this work.Then,two kinds of copper oxides were synthesized by chemical reduction method in aqueous systems.The catalytic activity of the samples were investigated using the reduction of nitrophenols to aminophenols with excess sodium borohydride as the model reaction.There are 5 chapters in this paper.Part 1,A localized surface plasmon resonance?LSPR?light-scattering strategy to study the effect of [Cu?dppz??L-Ser?]NO₃·H₂O on the stabilization of triplex DNA based on unmodified gold-nanoparticles?AuNPs?has been described in this work.Polypyridine copper complex,[Cu?dppz??L-Ser?]NO₃·H₂O,acted as an intercalator to improve the stability of the triplex structure in a weak alkaline environment.The LSPR light-scattering signal was enhanced dramatically by the existence of [Cu?dppz??L-Ser?]NO₃·H₂O,which illustrated the copper complex stabilized the triplex structure formed by single strand and duplex DNA parallel to the single strand DNA.The state of the Au NPs,protected by single-stranded DNA,changed from a dispersion state to an aggregation state in the presence of [Cu?dppz??L-Ser?]NO₃·H₂O.Electronic spectra and transmission electron microscopy were also used to explain the reason for the enhancement of the LSPR light-scattering.Furthermore,ethidium bromide?EB?was employed for comparison with the copper complex,and the results showed that [Cu?dppz??L-Ser?]NO₃·H₂O had a stronger effect on the enhancement of the stability of triplex than EB.The strategy was simple and had low toxicity.It may offer a new pathway for enhancing the stability of triplex DNA.Part 2,a novel localized surface plasmon resonance?LSPR?light scattering strategy for sensitive detection of silver ions?Ag⁺?and L-cysteine?Cys?was studied based on triplex-functionalized gold nanoparticle.Upon the addition of Ag⁺,the stability of triplex DNA that containing CG.C+ base were enhanced,however,Ag⁺ is apt to interact with cysteine,which can lead to instability of triplex.The stability and instability of triplex structure that containing CG.C⁺ base can indicated from the melting curve and LSPR light scattering by the system of triplex-functionalized gold nanoparticle.Under the optimized conditions,the novel strategy shows a nice selectivity towards both Ag⁺ and cysteine.The change of peak intensity by LSPR light scattering are all have a liner relationship with the concentration of Ag⁺ ranging from 0.5?M to 4.0?M and cysteine ranging from 0.125?M to 0.9?M.Besides,the interaction study between metal ions and amino acids is also interesting for understanding the possible detoxification mechanism of metal ions and the formation mechanism of triplex under a weak alkaline environment.Part 3,Self-assembled cuprous oxide nanoparticles supported on reduced graphene oxide are synthesized by a chemical reduction method in aqueous systems.The results of field emission scanning electron microscopy and transmission electron microscopy demonstrate that the obtained sample features a hollow ball structure through the self-assembly.Moreover,the cuprous oxide particles dissociate into tiny lamellar structures with a diameter of 3 nm in an aqueous medium.The catalytic activity of the sample was investigated using the reduction of nitrophenols to aminophenols with excess sodium borohydride as the model reaction.The kinetics of reduction was proved to follow pseudo first order kinetics.The rates of catalytic reduction of nitrophenols have been found to follow the sequence: 2-nitrophenol > 4-nitrophenol > 3-nitrophenol,and the activation energies are 50.17 kJ mol^-1,79.92 kJ mol^-1 and 63.86 kJ mol^-1 for 2-nitrophenol,3-nitrophenol and 4-nitrophenol,respectively.In addition,the reusability of the Cu₂O/RGO compounds was also studied and the results showed that the compounds could be reused many times with nearly invariable high catalytic efficiency.Part 4,To compare the catalytic activity,CuO/RGO was synthesized using the same synthesis method used for Cu₂O/RGO.The results of field emission scanning electron microscopy and transmission electron microscopy demonstrate that the obtained sample features a solid sphere structure.The catalytic activity of the sample was investigated using the reduction of nitrophenols to aminophenols with excess sodium borohydride as the model reaction.The kinetics of reduction was proved to follow pseudo first order kinetics.The results show that Cu₂O/RGO exhibits a considerably higher kapp than CuO/RGO at every temperature,which is 23.8 times that of Cu O/RGO when the reaction temperature is 293 K.