Surface-enhanced Raman spectroscopic detection of Bacillus subtilis spores using gold nanoparticle based substrates.
The detection of bacterial spores requires the capability of highly sensitive and biocompatible probes. This report describes the findings of an investigation of surface-enhanced Raman spectroscopic (SERS) detection of Bacillus subtilis spores using gold-nanoparticle (Au NP) based substrates as the spectroscopic probe. The SERS substrates are shown to be highly sensitive for the detection of B. subtilis spores, which release calcium dipicolinate (CaDPA) as a biomarker. The SERS bands of CaDPA released from the spores by extraction using nitric acid provide the diagnostic signal for the detection, exhibiting a limit of detection (LOD) of 1.5×10(9) spores L(-1) (or 2.5×10(-14) M). The LOD for the Au NP based substrates is quite comparable with that reported for Ag nanoparticle based substrates for the detection of spores, though the surface adsorption equilibrium constant is found to be smaller by a factor of 1-2 orders of magnitude than the Ag nanoparticle based substrates. The results have also revealed the viability of SERS detection of CaDPA released from the spores under ambient conditions without extraction using any reagents, showing a significant reduction of the diagnostic peak width for the detection. These findings have demonstrated the viability of Au NP based SERS substrates for direct use with high resolution and sensitivity as a biocompatible probe for the detection of bacterial spores.
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Han-Wen
HW
Cheng
Yuan-Yuan
YY
Chen
Xin-Xin
XX
Lin
Shuang-Yan
SY
Huan
Hai-Long
HL
Wu
Guo-Li
GL
Shen
Ru-Qin
RQ
Yu
D001412:Bacillus subtilis / Q000302:isolation & purification*; D006046:Gold / Q000032:analysis* / Q000737:chemistry; D053758:Nanoparticles / Q000032:analysis* / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013171:Spores, Bacterial / Q000302:isolation & purification; D013379:Substrate Specificity; D013499:Surface Properties
D006046:Gold