Fabrication and Comparative Quantitative Analysis of Plasmonic-Polymer Nanocomposites as Optical Platforms

Abstract

Plasmonic-polymer nanocomposites can serve as a multifunctional platform for a wide range of applications such as biochemical sensing and photothermal treatments, where they synergistically benefit from the extraordinary optical properties of plasmonic nanoparticles (NPs) and biocompatible characteristics of biopolymers. The field translation of plasmonic-polymer nanocomposites requires design rules for scalable and reproducible fabrication with tunable and predictable optical properties and achieving the best performance. The optical properties of NPs and the optimal analytical performance of nanocomposites could be affected by many fabrication parameters, but a fundamental understanding of such parameters is still minimal. Herein, we systematically investigated the NP distribution and their optical properties in gold nanostar (GNS)-polymer nanocomposites as a function of GNS concentration, polymer identity, and the method of GNS incorporation into a polymer matrix. We performed a comprehensive analysis of the single-particle scattering spectra of GNS incorporated into agarose gel and chitosan hydrogels via embedding and surface deposition, using dark-field spectroscopy. While relative GNS concentration affects the GNS scattering property distribution in both polymer matrices, chemical interactions between a polymer matrix and GNS is the key determinant of the GNS stability and homogenous distribution in nanocomposites. When GNS are embedded in a polymer matrix and there are stronger chemical interactions between GNS and a polymer, significantly less aggregation and a more homogenous distribution of GNS, which leads to a larger percentage of GNS optical property preservation, were observed at all the concentrations. In a proof-of-concept surface-enhanced Raman spectroscopy (SERS) study, we observed that the SERS detection efficiency is dictated by the analyte accessibility of GNS, which is governed by the polymer matrix porosity, polymer-GNS interactions, and other polymer physical characteristics. This work presents the interplay between key fabrication parameters and foundational design parameters for more predictable and reliable fabrication of plasmonic-polymer nanocomposites as an optical platform.

Direct Detection of Tobacco Mosaic Virus in Infected Plants with SERS-Sensing Hydrogels

“…The reduced sensing response of gelatin A could be attributed to positively charged amine moieties in the gelatin network forming a protective/isolating coating on the negatively charged surface of the nanoparticles. Similar interactions have been described in the literature, most recently in the encapsulation of nanostars in chitosan hydrogels. , Conversely, charge seems to play a role when comparing agar and agarose performance. Agar performed better than agarose, perhaps due to negatively charged polysaccharide present in the network repelling the sensors into the interstitial sites for better access to the target analytes.…”

“…Agaropectin, a mixture of sulfated galactan, d -glucuronic acid, and pyruvic acid, comprises the remaining mass of agar (approximately 30%). Agarose hydrogels have been demonstrated as a suitable substrate both for biological sensors and for nanoparticle-based materials. , Our hydrogels were prepared with 2% agar and 7% gelatin. These concentrations were selected as they were the lowest concentration of each material that resulted in gels with enough structural stability to cut into small pieces and handle without significant breakage.…”

Recent advances in nanotechnology for programmed death ligand 1-targeted cancer theranostics

“…Low-toxicity Au NPs have shown promise as alternatives to commercially available iodine-based contrast agents owing to their ability to provide enhanced contrast, increased cycle time, and disease-specific imaging. 58,59 Meir et al synthesized 20 nm gold NPs conjugated with PD-L1 antibodies to form aPD-L1-GNPs for the real-time detection of colon tumors in mice using CT imaging. 60 It revealed considerable variability in the uptake of PD-L1 antibody-Au NPs after treatment initiation for 48 h, which is likely due to the tumor heterogeneity in the mice (Fig.…”

Effect of the molecular weight on the sensing mechanism in polyethylene glycol diacrylate/gold nanocomposite optical transducers

“…Biosensors are expected to overcome the current limitations of traditional remote laboratory techniques, which include the need for trained personnel, expensive instrumentation, and long waiting times. Such long times are not compatible anymore with the maintenance of human health, food quality assessment, and environmental monitoring [ [1] , [2] , [3] , [4] , [5] , [6] , [7] ].…”