Ferritin as a photocatalyst and scaffold for gold nanoparticle synthesis
Source: Journal of Nanoparticle Research, Volume 13, Number 6, June 2011 , pp. 2563-2575(13)
Abstract:The ferrihydrite mineral core of ferritin is a semi-conductor capable of catalyzing oxidation/reduction reactions. This report shows that ferritin can photoreduce AuCl4 − to form gold nanoparticles (AuNPs). An important goal was to identify innocent reaction conditions that prevented formation of AuNPs unless the sample was illuminated in the presence of ferritin. TRIS buffer satisfied this requirement and produced AuNPs with spherical morphology with diameters of 5.7 ± 1.6 nm and a surface plasmon resonance (SPR) peak at 530 nm. Size-exclusion chromatography of the AuNP–ferritin reaction mixture produced two fractions containing both ferritin and AuNPs. TEM analysis of the fraction close to where native ferritin normally elutes showed that AuNPs form inside ferritin. The other peak eluted at a volume indicating a particle size much larger than ferritin. TEM analysis revealed AuNPs adjacent to ferritin molecules suggesting that a dimeric ferritin–AuNP species forms. We propose that the ferritin protein shell acts as a nucleation site for AuNP formation leading to the AuNP-ferritin dimeric species. Ferrihydrite nanoparticles (~10 nm diameter) were unable to produce soluble AuNPs under identical conditions unless apo ferritin was present indicating that the ferritin protein shell was essential for stabilizing AuNPs in aqueous solution.
Document Type: Research Article
Affiliations: 1: Department of Chemistry and Biochemistry, Brigham Young University, C-210 Benson Building, Provo, UT, 84602, USA 2: Department of Physics and Astronomy, Brigham Young University, N283 ESC Building, Provo, UT, 84602, USA 3: Department of Chemistry and Biochemistry, Brigham Young University, C-210 Benson Building, Provo, UT, 84602, USA, Email: firstname.lastname@example.org
Publication date: June 2011