Metallic nanoparticles embedded in Chitosan thin films for
development of biosensors
J. N Silva1,2, I. T. Cavalcanti3,4, R. F. Dutra3,4, A. Fontes1, B. S. Santos1, P. M. A. Farias1,2
Research Group on Nanostructures and Biological Interfaces – NIB, Universidade Federal
de Pernambuco, Recife, PE, Brazil
2
Graduate Program on Materials Science, PGMTR, Universidade Federal de Pernambuco,
Recife, PE, Brazil
3
Laboratory for Diagnostics Research, LAPED, Universidade de Pernambuco, Recife, PE,
Brazil
4
Northeast Biotechnology Network, Doctorate Program, RENORBIO, Brazil
1
Gold and Silver nanoparticles (NAu and NAg) embedded in thin films of the polycationic
sacharide Chitosan (Ch) were obtained by the heating at 70oC of Ch aqueous solution
containing NAu and NAg precursors (HAuCl4 and AgNO3, respectively). NAu and NAg were
obtained directly into the polymeric matrix. X-Ray Diffractometry and Transmission and
Scanning Electronic Microscopies (TEM and SEM), as well as spectroscopic and
electrochemical methods (cyclic voltametry and impedimetric measurements) were performed
in order to characterize the obtained materials. UV-Vis spectra presented typical plasmons
bands which are not observed in the UV-Vis spectra of Ch without NAu and NAg as can be
seen in Figure 1, left. FT-IR spectroscopy results showed changes in amine groups vibrational
modes at 1400 and 2800cm-1. These features strongly suggest that the NH2 groups effectively
actuate on the reduction of the metallic precursors. The films are 25µm thick. MEV images
showed that the obtained films are highly homogeneous (Figure 1, right). All the analyzed
results point to the feasibility of the obtained materials as potential biosensing substrates [1].
Keywords: metallic nanoparticles, chitosan, thin films.
Figure 1–Left: UV-Vis Absorption spectra and macroscopic aspect of the NAu and NAg
Chitosan films; Right: MEV images of Ch, Ch/NAu and Ch/NAg films.
[1] C. Shan et al., Biosensors and Bioelectronics 25, 1070 (2010).
Work supported by CNPq (INFo-MCT) and FACEPE.
e-mail: [email protected], Avenida Professor Morais Rego, 1235. Laboratório de
biofísica química Professor Ricardo Ferreira, Centro de ciências da saúde, Recife, PE,
Brazil.