This Small Business Innovation Research (SBIR) Phase I project aims to develop a novel substrate for sensing of biomolecules by Surface Enhanced Raman Spectroscopy (SERS). The substrate is expected to be stable, low cost , reproducible and can be functionalized to improve selectivity. Sensing of biomolecules and other chemicals has become increasingly important for point-of-care diagnostics in medical applications, controlling and monitoring environmental pollution, as well in improved detection of chemical warfare agents and explosives in homeland security applications. SERS is a vibrational spectroscopy and can provide chemical-fingerprint like information that is highly specific. This enables detection of many different species and also permits detection of multiple species in a single measurement. The lack of high quality, stable, low cost substrates, reproducibility of the enhancement and selectivity are all challenges that need to be overcome before commercialization can be sucessful. The type of structure developed in this project where SERS active nanoparticles are dispersed on the surface of a high surface area support is unique and can provide fundamental insights into SERS mechanisms as well as yield a substrate that can enable the development of commercial SERS based sensors and sensing mechanisms for a range of applications.
The broader impact/commercial potential of this project is that it has the potential to be a be a key enabler for commercial sensors or platforms based on Surface Enhanced Raman Spectroscopy (SERS). Development of chemical sensors is critical for industrial, medical and homeland security applications. A rapidly aging population, increased spending in the healthcare sector, increasing demand for point-of-care testing & monitoring solutions, shift towards alternate sites of healthcare, and increased occurrences of a number of chronic diseases drive the requirements for innovation in sensors. SERS is an emerging technique for optical sensors that has been shown to have a wide range of sensing capabilities, for example, The SERS based sensors currently under development have impact on homeland security and medical diagnostics applications and thus the technology proposed here can have a broad impact on these areas.
" Vesta Sciences San Diego, CA Sensing of biomolecules and industrial chemicals has become increasingly important for point-of-care diagnostics in medical applications, controlling and monitoring environmental pollution, providing tools for quality and process control in industrial applications, as well in improved detection of chemical warfare agents and explosives in homeland security applications. Raman spectroscopy has the potential for rapid label free detection of target molecules. Since it is vibrational spectroscopy, the technique can provide chemical-fingerprint like information that is highly specific. This enables detection of many different species and also permits detection of multiple species in a single measurement. However, the drawback is that the Raman signal from most systems is very weak and it is difficult to detect low concentrations or adsorbed molecules. In the 1970s, it was discovered that Raman scattering can be enhanced 105 to 106 times from molecules adsorbed or in close proximity to roughened noble metal surfaces with nanoscale features or nanoscale particles. This effect has led to the development of Surface Enhanced Raman Scattering (SERS) as a viable technique for molecular detection with high sensitivity. The enhancement is dependent on the availability of a SERS active substrate and much effort has been devoted to developing substrates that are stable and yield reproducible enhancement. Nanotechnology and advances in the synthesis of gold and silver nanoparticles, have led to an explosion in SERS related research for a range of biological, forensic and other industrial applications. However, the lack of high quality, stable, low cost SERS active substrates with reproducible enhancement and the selectivity of the technique are challenges to be overcome for commercial adoption on a larger scale. On the commercial front, there are only a few suppliers of substrates for SERS. Low-cost structurally stable substrates with reproducible enhancement factors are imperative for further development of SERS to be a viable commercial technique for the range of applications currently being explored in research laboratories. In this Phase 1 project, Vesta Sciences has successfully developed a novel silicon based SERS substrate. The substrate is created by the deposition of silver nanoparticles on a patented high surface area silicon support . Vesta has demonstrated that these substrates are SERS active with model molecules, exhibit reproducible and uniform enhancement and have excellent shelf life (activity is maintained for a period of two years). The substrates can be tailored to optimize enhancement for various molecules of interest, are very stable and easy to handle. SERS has been applied for direct detection of biologically relevant small molecules from antioxidants such as glutathione and glucose and biomarkers for biowarfare agents such as anthrax and biomarkers for cancer. SERS has also been used in forensic applications, detection of chemical warfare agents and for environmental applications. Vesta’s technology has the potential to be a key enabler for commercial sensors or platforms based on SERS as well as portable applications.
