Low-Cytotoxic Gold-Coated Silver Nanoflowers for Intracellular pH Sensing

Abstract

Recently, our group introduced the use of silver nanowires (AgNWs) as novel non-invasive endoscopic probes for detecting intracellular Raman signals. This method, although innovative and promising, relies exclusively on the plasmonic waveguiding effect for signal enhancement. It, therefore, requires sophisticated operational tools and protocols, drastically limiting its applicability. Herein, an advanced strategy is offered to significantly enhance the performance of these endoscopic probes, making this approach widely accessible and versatile for cellular studies. By uniformly forming gold structures on the smooth AgNW surface via a galvanic replacement reaction, the density of the light coupling points along the whole probe surface is drastically increased, enabling high surface-enhanced Raman scattering (SERS) efficiency upon solely focusing the excitation light on the gold-etched AgNW. The applicability of these goldetched AgNW probes for molecular sensing in cells is demonstrated by detecting site-specific and high-resolved SERS spectra of cell compartment-labeling dyes, namely, 4′,6-diamidino-2-phenylindole in the nucleus and 3,3′-dioctadecyloxacarbocyanine on the membrane. The remarkable spectral sensitivity achieved provides essential structural information of the analytes, indicating the overall potential of the proposed approach for cellular studies of drug interactions with biomolecular items.

Electrosynthesis of electrochemically reduced graphene oxide/polyaniline nanowire/silver nanoflower nanocomposite for development of a highly sensitive electrochemical DNA sensor

“…15 Besides, nanostructured metals, especially, nanostructures of silver, such as silver nanoparticles (AgNPs), silver nanowires (AgNWs) and silver nanoowers (AgNFs), exhibit excellent chemical and physical properties, so they are intensively studied and applied. [15][16][17] Thanks to special electrochemical properties, unique catalytic activity, high biocompatibility and reasonable cost, AgNPs, AgNWs and AgNFs are used in the development of electrochemical biosensors to amplify the signal and improve the sensitivity of the sensors. 15,[18][19][20] In previous studies, AgNPs and AgNWs have been decorated on carbon nanomaterials or conducting polymers to enhance the electrochemical activity of the nanocomposites.…”

Recent Progress of SERS Nanoprobe for pH Detecting and Its Application in Biological Imaging

“…In this connection, Zhang [53] successfully obtained the visualized intracellular pH value (pHi) and the pHi curve of living cells through the functionalized nanostars, thus visualizing the dynamic distribution of pHi in a single cell (Figure 4c). Similarly, Zhang's research group [54] compared the pKa information behavior and pH SERS sensitivity of near-spherical isotropic and flower-like anisotropic gold coated silver nanoparticles (Figure 4d). The experimental results show that the flowerlike nanoparticles with higher curvature exhibit a narrower pH sensitivity range and a higher sensitivity to pH range than the near-spherical nanoparticles.…”

Anisotropic transition metal–based nanomaterials for biomedical applications

“…(E) Gold–silver nanoflowers for live cells imaging. [ 145 ] Copyright 2015, the Owner Societies. (F) Schematic illustration of synthetic procedure for CuO nanoflowers.…”

“…Recently, Hiroshi Uji‐i copper (Cu) is another transition metal that can be easily converted into cubic nanomaterials prepared by gold‐coated silver nanoflowers (AuAgNFs) (Figures 7D and 7E). [ 145 ] The AuAgNFs could be able to detect pH changes in cells.…”