title: On-line SERS detection of single bacterium using novel SERS nanoprobes and a microfluidic dielectrophoresis device.
abstract: The integration of novel surface-enhanced Raman scattering (SERS) nanoprobes and a microfluidic dielectrophoresis (DEP) device is developed for rapid on-line SERS detection of Salmonella enterica serotype Choleraesuis and Neisseria lactamica. The SERS nanoprobes are prepared by immobilization of specific antibody onto the surface of nanoaggregate-embedded beads (NAEBs), which are silica-coated, dye-induced aggregates of a small number of gold nanoparticles (AuNPs). Each NAEB gives highly enhanced Raman signals owing to the presence of well-defined plasmonic hot spots at junctions between AuNPs. Herein, the on-line SERS detection and accurate identification of suspended bacteria with a detection capability down to a single bacterium has been realized by the NAEB-DEP-Raman spectroscopy biosensing strategy. The practical detection limit with a measurement time of 10 min is estimated to be 70 CFU mL(-1) . In comparison with whole-cell enzyme-linked immunosorbent assay (ELISA), the SERS-nanoprobe-based biosensing method provides advantages of higher sensitivity and requiring lower amount of antibody in the assay (100-fold less). The total assay time including sample pretreatment is less than 2 h. Hence, this sensing strategy is promising for faster and effective on-line multiplex detection of single pathogenic bacterium by using different bioconjugated SERS nanoprobes.
authors.affiliation: Department of Chemistry and Biochemistry and Center for Nano Bio-Detection (AIM-HI), National Chung Cheng University, Chiayi, 62102, Taiwan.
authors.forename: Hsing-Ying
authors.initials: HY
authors.lastname: Lin
authors.forename: Chen-Han
authors.initials: CH
authors.lastname: Huang
authors.forename: Wen-Hsin
authors.initials: WH
authors.lastname: Hsieh
authors.forename: Ling-Hsuan
authors.initials: LH
authors.lastname: Liu
authors.forename: Yuan-Chuen
authors.initials: YC
authors.lastname: Lin
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Chu
authors.forename: Shi-Ting
authors.initials: ST
authors.lastname: Wang
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Kuo
authors.forename: Lai-Kwan
authors.initials: LK
authors.lastname: Chau
authors.forename: Chiou-Ying
authors.initials: CY
authors.lastname: Yang
mesh_terms: D004586:Electrophoresis / Q000295:instrumentation*; D004797:Enzyme-Linked Immunosorbent Assay; D053768:Metal Nanoparticles; D044085:Microfluidics / Q000295:instrumentation*; D046529:Microscopy, Electron, Transmission; D015335:Molecular Probes; D019779:Salmonella enterica / Q000302:isolation & purification*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D015335:Molecular Probes
keywords: SERS nanoprobes; bacteria; biosensors; dielectrophoresis; raman spectroscopy