Targeted highly sensitive detection/eradication of multi-drug resistant Salmonella DT104 through gold nanoparticle-SWCNT bioconjugated nanohybrids

Abstract

Monoclonal antibody-conjugated sphere-shaped gold nanoparticles were combined with single-walled carbon nanotubes (SWCNTs) to create a nanohybrid system to selectively detect and eradicate multiple drug resistant Salmonella (MDRS) typhimurium DT104 bacteria. The Raman signal intensity from Rhodamine 6G (Rh6G) modified monoclonal AC04 antibody SWCNTs-gold nanoparticle (SWCNT-GNPs) hybrid provided a SERS enhancement by several orders of magnitude to detect the MDRS bacteria over the GNP system. A targeted photothermolysis experiment using 670 nm light at 2 W cm(-2) for 15 min, resulted in selective and irreparable damage to more than 99% Salmonella DT104 at the concentration of 10(5) CFU mL(-1). In comparison to solely SWCNTs or GNPs, our SWCNT-GNPs nanohybrids have also shown a better photothermal efficiency.

Fig. 1

FTIR spectra of aminothiophenol attached SWCNTs.

Fig. 2

TEM images illustrating: (A) GNPs. (B) GNPs-decorated SWCNTs. (C) Salmonella bound by AC04 antibody conjugated GNPs-decorated SWCNTs. (D) Lack of E.Coli binding by AC04 antibody conjugated GNPs-decorated SWCNTs.

Fig. 3

SERS enhancement (SERS intensity change before and after addition of bacteria) due to the addition of Salmonella to monoclonal AC04 antibody-conjugated, GNPs-decorated SWCNTs.

Fig. 4

UV Absorption spectra for only SWCNTs, 0.3 nM GNPs, 0.3 nM GNPs attached SWCNTs, and SWCNTs-GNPs-Salmonella

Fig. 5

Photo thermal killing of Salmonella. (A) SWCNTs-GNPs-antibody-Salmonella under laser irradiation for 15 min. (B) GNPs-antibody-Salmonella under laser irradiation for 15 min. (C) SWCNTs-antibody-Salmonella under laser irradiation for 15 min. (D) SWCNTs-GNPs-antibody-Salmonella before laser irradiation. (E) Only Salmonella under laser irradiation for 15 min

Scheme 1

Schematic representation shows the synthetic protocol for the functionalization of SWCNTs, the formation of GNP attached SWCNTs, and SWCNTs-GNPs-antibody-Salmonella.