Self Assembly of Plasmonic Substrates for Trace Analyte Detection

One of the most significant challenges facing physical and biological scientists is the accurate detection and quantification of trace levels of analytes within a local environment. The ability to perform such sensitive and selective measurements is invaluable when it comes to monitoring toxins or even pollutants within either an isolated environment, in- the-field, or within complex mixtures. Perhaps even more important is being able to perform such measurements in real-time with small, portable, and robust instrumentation. Importantly, over the past few years a number of techniques with sufficient sensitivity to detect trace analytes have been developed predominantly within a laboratory setting. For example, optical methods incorporating the measurement of absorption and emission processes have proved most successful due to their ability to detect signals down to the single molecule level. More recently, surface enhanced Raman spectroscopy (SERS) has been and is becoming a very popular tool for performing label-free measurements with similar levels of sensitivity. Importantly, SERS offers additional benefits as vibrationally rich “fingerprints” can be obtained making it possible to detect trace analytes within polluted environment or alternatively analytes with weak vibrational cross-sections. Thus, methods to assemble two-dimensional arrays with controlled spacing could revolutionize how substrates are formed and employed. Various methods exist to fabricate such structures including lithographic and chemical approaches. Metallic structures can also be fabricated from self assembled non-metallic scaffolds. However, minimizing the gap between particles or cavities and the complexity of substrate preparation, while maximizing uniformity is crucial to maximizing the electromagnetic field enhancement. A disposable, self-assembled approach is highly advantageous for practical applications. In this talk I will address this by demonstrating novel strategies for the self-assembly of SERS active substrate.

joshua.edel@gmail.com