Polyvinylpyrrolidone- (PVP-) coated silver aggregates for high performance surface-enhanced Raman scattering in living cells

Abstract

A biocompatible and stable surface-enhanced Raman scattering (SERS) probe has been successfully synthesized through a simple route with silver aggregates. Polyvinylpyrrolidone (PVP), a biocompatible polymer, was utilized to control the aggregation process and improve the chemical stability of the aggregates. Extinction spectroscopy and TEM results show the aggregation degree and core-shell structure of the probe. It is found that when we employ 4-mercaptobenzoic acid (4MBA), crystal violet (CV), Rhodamine 6G (R6G) or 4,4'-bipyridine molecules as Raman reporters, the SERS signal from the proposed probe can remain at a high level under aggressive chemical environments, even after being incorporated into living cells. In comparison with the traditional probes without the PVP shell, the new ones exhibit strong surface-enhanced effects and low toxicity towards living cells. We demonstrate that the PVP-coated silver aggregates are highly SERS effective, for which the fabrication protocol is advantageous in its simplicity and reproducibility.

Surface enhanced Raman spectroscopy (SERS): Potential applications for disease detection and treatment

“…To minimise or prohibit degradation from the surrounding environment nanostructures can be afforded a certain degree of stability by silica [13,76] or polymer encapsulation. [71,77,78] The incorporation of polyethylene glycol (PEG) again offers protection from the chemical and physical environment, minimisation of non-specific binding [79] and, depending on the terminal functionality, PEG is readily amenable for bioconjugation to a range of targeting ligands. [80] …”

Receptor-targeted, drug-loaded, functionalized graphene oxides for chemotherapy and photothermal therapy

“…36 PVP, a biocompatible and nontoxic polymer, was used to solve this problem by acting as a dispersant and stabilizing agent for GO. 18,19 Following the addition of PVP to GO, the FA-GO dispersion remained stable, even after 24 hours in different media (image not shown). Furthermore, the FA-GO/SF dispersion also maintained a high stability in different media for 24 hours, indicating that PVP was an effective stabilizer in this formulation ( Figure S2C and D).…”

“…17 To overcome this problem, the current study used polyvinyl pyrrolidone (PVP), a nontoxic, nonionic, biocompatible polymer, as a dispersant and stabilizing agent. [18][19][20][21][22] Furthermore, folic acid (FA) was conjugated to GO to form FA-GO. Folate receptors are abundantly expressed on cancer cells and therefore provide a target site for tumor drug delivery, while GO facilitates photothermal therapy.…”

“…This result reflected the nonionic nature of PVP. 18 Further addition of FA increased the zeta potential because of the presence of OH. 37 Figure 5A presents the FTIR spectra of graphite, GO, and the GO derivatives.…”

Preparation and Characterization of Silica-coated Gold Nanoflowers (AuNFs) with Raman Dye Encoding

“…Recently, increasing attention has been directed for wrapping a SERS nanoprobe with a coating layer which can protect from oxidative environment. 6,7 Furthermore, it would be very beneficial if the coating layer could provide conjugation with functional groups of various bioagents.…”