Use of gold nanoparticles as crosslink agent to form chitosan nanocapsules: Study of the direct interaction in aqueous solutions

• Published in: Journal of inorganic biochemistry Vol. 135; pp. 77 - 85
• Main Authors: Prado-Gotor, R., López-Pérez, G., Martín, M.J., Cabrera-Escribano, F., Franconetti, A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.06.2014
• Subjects: Adsorption; Chitosan; Chitosan - chemistry; Cross-Linking Reagents - chemistry; Electrostatic interaction; Gold - chemistry; Gold nanoparticles; Hydrogen-Ion Concentration; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Nanocapsules - chemistry; Nanocapsules - ultrastructure; Particle Size; Solutions; SPB deconvolution; Zeta potential; Chitosan; SPB deconvolution; Zeta potential; Gold nanoparticles; Electrostatic interaction
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2014.03.005

A systematic study of the interaction between free anionic gold nanoparticles and chitosan in a solution is presented. A spectroscopic study of the interaction between 10nm gold nanoparticles and low molecular weight chitosan is reported as a function of the concentration and pH of the polymer in a solution. Zeta potential measurements and TEM images indicate the effective aggregation of the nanoparticles in the presence of chitosan. At the same time, anionic gold nanoparticles act as crosslink agents to form chitosan nanocapsules with an average molecular size of 260nm. The changes of the surface plasmon band due to the adsorption of the polymer on the nanoparticle surface allow using of the citrate gold nanoparticles as sensors of the polymer for analytical purposes. The limit of detection for chitosan biopolymer is 69nM. The optimum pH for the interaction between the biopolymer and the nanoparticles is found at a value of 6.4, obtained from spectrophotometric measurements and applying a deconvolution analysis of the experimental data. A simple model based on molecular surface electrostatic interactions is proposed to understand the pH dependence of the investigated system. Formation of chitosan nanocapsules induced by gold nanoparticles. A study of direct interaction as a function of the biopolymer concentration and solution pH [Display omitted] •A spectroscopic study of the interaction between 10nm AuNPs and chitosan is presented.•TEM image measurements indicate the aggregation of the AuNPs in the presence of chitosan•Anionic AuNPs act as crosslink agents to form chitosan nanocapsules of 260nm.•The detection limit for chitosan is 7×10−8M.•Deconvoluted SPB and an electrostatic model show a maximum interaction at pH6.4.