Trace molecular detection with surface-enhanced Raman spectroscopy
From chemical and biological weapons detection to drug delivery analysis, modern-day society has become increasingly dependent on efficient and reliable molecular detection. Efficiency and sensitivity, however, are difficult to achieve in a single system. Surface enhanced Raman spectroscopy (SERS) has achieved single-molecule detection using the field-effect near a metal surface to enhance the measureable molecular “fingerprint“ 106-1010 fold over conventionally Raman spectroscopy. In conventional SERS, the metal forms a 2-dimenional layer and only molecules bonded or adhered to the metal can be enhanced resulting in a very small sampling volume. Conversely, 3-dimensional systems including porous silicon with gold nano-particles have shown great enhancement but rely on exceedingly slow diffusion into closed capillaries, yielding long data acquisition times. Decreasing the sampling time of these systems while maintaining the sensitivity would provide a robust platform for future trace molecular detection.
3-dimensional optofluidic SERS platform
University of Michigan researchers have developed a SERS platform that incorporates flow-through capabilities and a 3-dimensional sampling volume. These capabilities provide better than 100 fM concentration detection in less than 5 minutes of sampling. Industrial techniques used to form tailorable capillaries and effective data collection in both the transverse and longitudinal directions yield a versatile platform for both gas and liquid flow applications that is easily incorporated into conventional systems. Their system has the sensitivity, efficiency and versatility necessary to augment today’s commercial molecular detection systems.
Applications and Advantages
- Trace molecular detection
- Chemical and biological weapons detection
- Drug delivery analysis
- Enhancement factor of 109-1010
- Better than 100 fM concentration detection
- Fast sampling