Amino Acid-and Peptide-directed Synthesis And Properties Of Chiral-morphology Gold Nanoparticles

The chiral signals of molecules are generally small and appear in the deep ultraviolet and ultraviolet regions,how to amplify the chiral signals of molecules and transmit it to the visible light and even the near-infrared region has gradually become one of the new challenges.Due to the small size effect,quantum size effect and tunability of surface plasma resonance of noble metal nanoparticles(NPs),the combination of chiral molecules and NPs has become a new research hotspot.However,growing crystalline noble metals with dissymmetric morphology is challenging.Although lithographic approaches have been successfully applied to fabricate chiral gold NPs,their scalability remains limited.Advances in the colloidal synthesis of noble metal NPs achieved during the past decades suggest realistic prospects for the production of plasmonic NPs with diverse morphologies,including chiral ones.The presence of chiral amino acids during growth can guide the formation of NPs with distinct handedness.The enantioselective interaction of amino acids with chiral geometrical elements naturally appearing at particular NP facets,has been claimed to induce the observed shape evolution into twisted geometries with high dissymmetry factors.In the first part,for the first time,we have used glutathione oligomers to induce the synthesis of three-dimensional lamella-shaped chiral gold nanoparticles with distorted morphology and exhibited good circular dichroic activity in the visible light region.In addition,GSH oligomers with a certain helical conformation were confirmed to form a complex with Au~+in the growth solution,and then deposited on the surface of gold seeds in a certain orientation,and finally grew into lamella-shaped chiral gold nanoparticles with distorted morphology.By using hexamethylenetetramine(HMT)and ascorbic acid(AA)as synergistic reductants to increase the reduction rate,the curved chiral gold nanoparticles with tunable surface plasmonic resonance were successfully constructed,which laid a good foundation for the subsequent application of the chiral particles.In the second part,we first used cysteine to induce the synthesis of branched chiral gold nanoparticles with chiral morphology.In addition,a similar method was used to synthesize gold nanorods with chiral morphologies,proving that the construction method we adopted has certain universality.Surprisingly,the above chiral gold nanoparticles with different morphologies exhibited extremely strong thermal stability without any additional treatment.We also deposited palladium on the surface of branched chiral particles,and successfully constructed chiral gold-palladium bimetallic nanoparticles with tunable surface plasmon resonance range.The P-nitrophenol(4-NP)reduction experiment verified that the particles have good catalytic activity.This chiral bimetallic nanoparticle with both circular dichroism and catalytic activity has shown great application potential in the fields of chiral catalysis.In summary,chiral gold nanoparticles with different chiral morphologies and tunable surface plasmonic resonance range were synthesized by the induction of amino acid and polypeptide,and the universality of the construction method was proved.It provides a new insight for the synthesis and application of chiral nanoparticles with more abundant morphologies.