Gold Nanoparticle Embedded, Self-Sustained Chitosan Films as Substrates for Surface-Enhanced Raman Scattering

Abstract

In this work, self-sustained, biocompatible, biodegradable films containing gold nanostructures have been fabricated for potential application in nanobioscience and ultrasensitive chemical and biochemical analysis. We report a novel synthesis of gold nanoparticles mediated by the biopolymer chitosan. Self-supporting thin films are formed from the resultant gold-chitosan nanocomposite solutions and characterized by UV-visible surface plasmon absorption, transmission electron microscopy, atomic force microscopy, infrared absorption, and Raman scattering measurements. Results demonstrate control over the size and distribution of the nanoparticles produced, which is promising for several applications, including the development of biosensors. As a proof of principle, we demonstrate that gold-chitosan films can be employed in trace analysis using surface-enhanced Raman scattering.

Toxicity and antibacterial assessment of chitosan-coated silver nanoparticles on human pathogens and macrophage cells

“…24,25 For these reasons, chitosan has received great attention in the fields of medicine, food, chemicals, pharmaceuticals, and agriculture. [26][27][28][29] Although several independent studies have shown applications of nanoparticles in various fields, studies describing their impact on counteracting bacterial infections are limited. In this study, chitosan-stabilized AgNPs (CS-AgNPs) were synthesized, characterized by transmission electron microscopy (TEM) and dynamic light scattering, and tested for antibacterial activity against a panel of human pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, and Mycobacterium smegmatis, representing Gram-positive, Gram-negative, and acid-fast bacteria.…”

Successively amplified electrochemical immunoassay based on biocatalytic deposition of silver nanoparticles and silver enhancement

“…Based on these advantages, colloidal gold was first applied as TEM marker in 1971 (Faulk and Taylor, 1971), and was then introduced for SEM in 1975 (Horisberger et al, 1975). Recently, besides the application of metal nanoparticles in some analytical methods such as UV-vis (Schofield et al, 2006), Raman (Ni et al, 1999;Santos et al, 2004) and time-resolved fluorescence spectroscopy (Ipe and Thomas, 2004), SPR (He et al, 2000;Lyon et al, 1998) or QCM techniques (Zhou et al, 2000), a new electrochemical metalloimmunoassay by using colloidal gold as label was reported, which pushed the sensitivity of immunoassay to the picomolar domain (Dequaire et al, 2000). Further sensitivity enhancement can be obtained by the application of metal-enhanced gold nanoparticles, where functional gold nanoparticles act as catalysts to reduce gold or silver ions on themselves.…”

Green Synthesis, Cytotoxicity and Utilization of Carboxymethylchitosan-Stabilized Gold Nanoparticles.

“…So that we suggest that free amino groups in O-CMCS could bind with gold nanoparticles to stabilize it. When chitosan used instead of O-CMCS to stabilize AuNPs aggregation of nanoparticles occurs due to chitosan insoluble in both neutral and alkaline medium [11,14]. Figure 2 shows TEM images of the O-CMCS-AuNPs nanocomposites.…”

“…In the preparation of gold nanoparticles by using chitosan biopolymer, the NH 2 groups used to stabilize gold nanoparticles [11,12]. However precise control needed to avoid nanoparticles aggregations [11,13].Due to poor solubility of chitosan. Few papers found in the literature dealing with the direct application of chitosan and AuNPs nanocomposites.…”