A Graphene–Silver Nanoparticle–Silicon Sandwich SERS Chip for Quantitative Detection of Molecules and Capture, Discrimination, and Inactivation of Bacteria

Abstract

There currently exists increasing concerns on the development of a kind of high-performance SERS platform, which is suitable for sensing applications ranging from the molecular to cellular (e.g., bacteria) level. Herein, we develop a novel kind of universal SERS chip, made of graphene (G)-silver nanoparticle (AgNP)-silicon (Si) sandwich nanohybrids (G@AgNPs@Si), in which AgNPs are in situ grown on a silicon wafer through hydrofluoric acid-etching-assisted chemical reduction, followed by coating with single-layer graphene via a polymer-protective etching method. The resultant chip features a strong, stable, reproducible surface-enhanced Raman scattering (SERS) effect and reliable quantitative capability. By virtues of these merits, the G@AgNPs@Si platform is capable for not only molecular detection and quantification but also cellular analysis in real systems. As a proof-of-concept application, the chip allows ultrahigh sensitive and reliable detection of adenosine triphosphate (ATP), with a detection limit of ∼1 pM. In addition, the chip, serving as a novel multifunctional platform, enables simultaneous capture, discrimination, and inactivation of bacteria. Typically, the bacterial capture efficiency is 54% at 10 CFU mL bacteria, and the antibacterial rate reaches 93% after 24 h of treatment. Of particular note, Escherichia coli and Staphylococcus aureus spiked into blood can be readily distinguished via the chip, suggesting its high potential for clinical applications.

Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy

“…SERS is well-suited for bacteria detection from molecular to cellular level due to its sensitivity, selectivity, and compatiblity with other techniques. A representative work was presented by Meng et al [ 133 ] in which a new type of SERS chip, consisting a sophisticated sandwich graphene (G)-AgNP-silicon (Si) nanohybrids, has been developed. The chip system could achieve both molecular detection and cellular analysis in samples.…”

“…For the SERS detection of different types of bacterial component molecules, more sophisticated nanomaterials, complicated microfluidic chips [ 133 ], and new types of recognition molecules such as nanoyeast single-chain variable fragment [ 141 ], were designed, fabricated, and used to prepare the SERS-active substrate.…”

“… Schematic of the chip system for the analysis of ATP and bacteria [ 133 ]. Reproduced with permission from [ 133 ]. American Chemical Society, 2018.…”

Chemical bonding mechanism in SERS effect of pyridine by CuO nanoparticles

“…This phenomenon has been used to detect a variety of compounds and molecules . Au thin film has been implemented for the detection of exosomes in breast cancer studies,similarly viruses and bacteria and chemical residues . With respect to metallic oxides, CuO and C u 2 O have been used in the study of neurotransmitters and the detection of R6G molecule,respectively.…”

Fabrication of Reduced Graphene Oxide-Ag Nanocomposites and Analysis on the Interaction with BSA

“…It has been proved that graphene and AgNPs can produce synergistic reaction and enhance antibacterial effect. Nanoparticles with special properties of graphene and AgNPs are effective medical nanomaterials, which have attracted wide interest [18][19][20][21][22][23]. Therefore, the formation of nanoparticle-protein corona of graphene oxide-silver nanoparticles with BSA has been investigated in our previous work [24][25][26].…”