Bionanoconjugates of tyrosinase and peptide-derivatised gold nanoparticles for biosensing of phenolic compounds

• DOI: 10.1007/s11051-010-0099-8
• Publication Date: 2010-10-05T12:27:37Z
• Authors: J. Cortez; E. Vorobieva; D. Gralheira; I. Osório; L. Soares; N. Vale; E. Pereira; P. Gomes; R. Franco
• Keywords: Materials engineering; Ciências da engenharia e tecnologias::Engenharia dos materiais; Engenharia dos materiais; Engineering and technology::Materials engineering; 01 natural sciences; 0104 chemical sciences

Bionanoconjugates of the enzyme tyrosinase (TYR) and gold nanoparticles (AuNPs) functionalised with a peptide (CALNN) were produced in solution and characterised. The formation of stable TYR–AuNP:CALNN bionanoconjugates (BNCs) was supported by a decrease of the surface charge of the BNCs as determined by ζ-potential and an increase in hydrodynamic diameter as determined by Dynamic Light Scattering (DLS). UV/Vis studies of pH-induced aggregation revealed distinct protonation patterns for the BNCs when compared with AuNP:CALNN alone, further substantiating BNC formation. Activity studies of the BNCs for the reduction of di-phenols in solution indicated that TYR not only remains active after conjugation, but interestingly its activity in the BNCs is higher than for the free enzyme. In conclusion, AuNP:CALNN can provide a suitable platform for the immobilisation of TYR, leading to BNCs with increased enzyme activity and a wider pH working range, with promising uses in electrochemical biosensors for the detection of mono- and di-phenolic compounds.