title: pH induced protein-scaffold biosynthesis of tunable shape gold nanoparticles.
abstract: In this paper, a pH-inductive protein-scaffold biosynthesis of shape-tunable crystalline gold nanoparticles at room temperature has been developed. By simple manipulation of the reaction solution's pH, anisotropic gold nanoparticles including spheres, triangles and cubes could be produced by incubating an aqueous solution of sodium tetrachloroaurate with Dolichomitriopsis diversiformis biomasses after immersion in ultrapure Millipore water overnight. A moss protein with molecular weight of about 71 kDa and pI of 4.9 was the primary biomolecule involved in the biosynthesis of gold nanoparticles. The secondary configuration of the proteins by CD spectrum implied that the moss protein could display different secondary configurations including random coil, α-helix and intermediate conformations between random coil and α-helix for the experimental pH solution. The growth process of gold nanoparticles further showed that the moss protein with different configurations provided the template scaffold for the shape-controlled biosynthesis of gold nanoparticles. The constrained shape of the gold nanoparticles, however, disappeared in boiled moss extract. The gold nanoparticles with designed morphology were successfully reconstructed using the moss protein purified from the gold nanoparticles. Structural characterizations by SEM, TEM and SAED showed that the triangular and cubic gold nanoparticles were single crystalline.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, People's Republic of China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: He
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Ren
authors.forename: Zhihe
authors.initials: Z
authors.lastname: Qin
mesh_terms: D019068:Bryopsida / Q000737:chemistry / Q000378:metabolism; D002712:Chlorides / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D003116:Color; D003460:Crystallization / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D006046:Gold / Q000737:chemistry* / Q000378:metabolism; D017612:Gold Compounds / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D002712:Chlorides; D017612:Gold Compounds; D010936:Plant Extracts; D010940:Plant Proteins; D006046:Gold; C024568:gold tetrachloride, acid