Measurement of 100 B. anthracis Ames spores within 15 minutes by SERS at the US Army Edgewood Chemical Biological Ctr.

Since the distribution of Bacillus anthracis-Ames spores through the US Postal System, there has been a persistent fear that biological warfare agents will be used by terrorists against our military abroad and our civilians at home. While there has been substantial effort since the anthrax attack of 2001 to develop analyzers to detect this and other biological warfare agents, the analyzers remain either too slow, lack sensitivity, produce high false-positive rates, or cannot be fielded. In an effort to overcome these limitations we have been developing a surface-enhanced Raman spectroscopy system. Here we describe the use of silver nanoparticles functionalized with a short peptide to selectively capture Bacillus anthracis spores and produce SER scattering. Specifically, measurements of 100 B. anthracis-Ames spores/mL in ∼25 minutes performed at the US Army\u27s Edgewood Chemical Biological Center are presented. The measurements provide a basis for the development of systems that can detect spores collected from the air or water supplies with the potential of saving lives during a biological warfare attack. © 2014 SPIE

Selective detection of 1000 B. Anthracis spores within 15 minutes using a peptide functionalized SERS assay

A surface-enhanced Raman spectroscopy (SERS) assay has been designed to detect Bacillus anthracis spores. The assay consists of silver nanoparticles embedded in a porous glass structure that have been functionalized with ATYPLPIR, a peptide developed to discriminately bind B. anthracis versus other species of Bacillus. Once bound, acetic acid was used to release the biomarker dipicolinic acid from the spores, which was detected by SERS through the addition of silver colloids. This SERS assay was used to selectively bind B. anthracis with a 100-fold selectivity versus B. cereus, and to detect B. anthracis Ames at concentrations of 1000 spores per mL within 15 minutes. The SERS assay measurements provide a basis for the development of systems that can detect spores collected from the air or from water supplies. © 2014 the Partner Organisations

Optimization of Surface-Enhanced Raman Spectroscopy Conditions for Implementation into a Microfluidic Device for Drug Detection

A microfluidic device is being developed by University of California–Santa Barbara as part of a joint effort with the United States Army to develop a portable, rapid drug detection device. Surface-enhanced Raman spectroscopy (SERS) is used to provide a sensitive, selective detection technique within the microfluidic platform employing metallic nanoparticles as the SERS medium. Using several illicit drugs as analytes, the work presented here describes the efforts of the Edgewood Chemical Biological Center to optimize the microfluidic platform by investigating the role of nanoparticle material, nanoparticle size, excitation wavelength, and capping agents on the performance, and drug concentration detection limits achievable with Ag and Au nanoparticles that will ultimately be incorporated into the final design. This study is particularly important as it lays out a systematic comparison of limits of detection and potential interferences from working with several nanoparticle capping agentssuch as tannate, citrate, and boratewhich does not seem to have been done previously as the majority of studies only concentrate on citrate as the capping agent. Morphine, cocaine, and methamphetamine were chosen as test analytes for this study and were observed to have limits of detection (LOD) in the range of (1.5–4.7) × 10^–8 M (4.5–13 ng/mL), with the borate capping agent having the best performance

Analytical SERS : general discussion

George Schatz opened a general discussion of the paper by Zhong-Qun Tian: The dependence of Raman intensities with the angle of incidence and angle of scattering is an important issue. This was descirbed for flat surfaces long ago (before SERS) by Greenler and Schlager. How do your results differ

Analytical SERS: general discussion

Discussions.Peer Reviewe