Concurrent zero-dimensional and one-dimensional biomineralization of gold from a solution of Au³⁺and bovine serum albumin

Abstract

A technique was developed for preparing a novel material that consists of gold nanoparticles trapped within a fiber of unfolded proteins. These fibers are made in an aqueous solution that contains HAuCl4 and the protein, bovine serum albumin (BSA). By changing the ratio of gold to BSA in solution, two different types of outcomes are observed. At lower gold to BSA ratios (30–120), a purple solution results after heating the mixture at 80 °C for 4 h. At higher gold to BSA ratios (130–170), a clear solution containing purple fibers results after heating the mixture at 80 °C for 4 h. UV–Vis spectroscopy and light scattering techniques show growth in nanocolloid size as gold to BSA ratio rises above 100. Data indicate that, for the higher gold to BSA ratios, the gold is sequestered within the solid material. The material mass, visible by eye, appears to be an aggregation of smaller individual fibers. Scanning electron microscopy and transmission electron microscopy indicate that these fibers are primarily one-dimensional aggregates, which can display some branching, and can be as narrow as 400 nm in size. The likely mechanism for the synthesis of the novel material is discussed.

Forced Biomineralization: A Review

“…Thermophilic microorganisms, in particular, seem to be an appreciable source of bioinspiration for designing new materials through approaches in extreme biomimetics. For example, a novel approach was developed for preparing a composite biomaterial that consists of gold nanoparticles trapped within an unfolded protein, the bovine serum albumin (BSA) fiber [ 63 ]. In general, the formation of secondary gold nano- and micro-grains via biomineralization, using diverse microorganisms, has stimulated the development of gold-based biotechnology [ 64 , 65 , 66 , 67 ].…”

A Hybrid Integrated Laboratory and Inquiry-Based Research Experience: Replacing Traditional Laboratory Instruction with a Sustainable Student-Led Research Project

“…We slightly altered our syllabus for that semester in order to explore this material in more detail. We published our findings in a research paper . And, while there was a slight detour in order to better understand these results, the main drive of the semester was in exploring ways to modify the homogeneous AuNPs through bioconjugation.…”

“…The students have responded favorably to the change. The students and faculty have produced one published research article from this work and are in the process of submitting a second publication. The faculty are active in submitting research grants based on, and intended to support, the students’ work.…”

Combining Energy Conversion and Storage: A Solar Powered Supercapacitor

“…Upon incorporation of Au fibers in the TiO2/CdS film, the resulting TiO 2 /CdS/Au film shows an increase in absorption in the same wavelength region(Figure 3a, line (ii)) which surprisingly does not coincide with the λSPR(max) of Au fibers. The Au fiber colloid shows a distinct absorption peak at 530 nm corresponding to surface plasmon resonance (λSPR(max)), typical of metal NPs(Figure 3b, line (i))[40]. The absorption increment of TiO2/CdS(Figure 3a, line (ii)) is effected either by scattering of light by Au plasmons, which increase the optical path length of light within the film matrix and enhance the CdS QD's absorption and also by the near field coupling between the surface plasmon polaritons and the excited state of the dots[41].…”