Kinetics and growth mechanism of the photoinduced synthesis of silver nanoparticles stabilized with lysozyme

GIMÉNEZ, RODRIGO E.; SOSA MORALES, MARCELO C.; GRAMAJO FEIJOO, MARCELO E.; GRAMAJO FEIJOO, MARCELO E.; MORÁN VIEYRA, FAUSTINO E.; MORÁN VIEYRA, FAUSTINO E.; REY, VALENTINA; TUTTOLOMONDO, MARÍA E.; BORSARELLI, CLAUDIO D.; REY, VALENTINA; TUTTOLOMONDO, MARÍA E.; BORSARELLI, CLAUDIO D.; GIMÉNEZ, RODRIGO E.; SOSA MORALES, MARCELO C.

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Año: 2018 vol. 172 p. 10 - 16

0927-7765

A fast and single-step procedure is reported for the preparation of stable solutions of spherical-shaped silver nanoparticles (AgNPs) coated with lysozyme (LZ). The preparation of the AgNP@LZ nanocomposites was based on the reduction of Ag + with ketyl radicals photo-generated by the UVA-photolysis of the benzoin I-2959. Both reaction precursors bind to LZ, modifying its superficial charge and conformational structure. The photo-induced kinetics of formation of the AgNPs as a function of the LZ concentration was monitored in-situ by UV?vis absorption spectroscopy. The multivariate curve resolution-alternating least square (MCR?ALS) method was used for the deconvolution of the kinetic curves for each transient species formed before the growth of the final AgNPs colloids. The Kolmogorov-Johnson-Mehl-Avrami (KJMA) model to describe the formation of the AgNPs was used, and the respective first-order rate constants for the growth of the AgNPs as a function of the lysozyme concentration were calculated and the role of the protein capping in the growth kinetics was evaluated. Despite the protein being partially oxidized by the photo-generated radicals, it was strongly adsorbed onto the silver surface forming a tight coating shell around the AgNPs of approximately 30?60 protein molecules. As a result of the partial denaturation and crowded packing, its intrinsic lytic activity was strongly reduced.