Comparing Surface Enhanced Raman Spectroscopy from Colloidal Gold Nanoparticles and Nanocages
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2015 SPIE. A point of care biosensor capable of detecting biomarkers in a low concentration in blood samples can have a great impact on the healthcare community. Surface Enhanced Raman Spectroscopy (SERS) is one potential means of monitoring analytes at low concentrations. Toward a continuing effort to use SERS for point of care biosensing, in this paper spherical gold colloid and nanocages are analyzed and compared to determine which substrate has better utility. Gold colloid is and has been a popular substrate used in SERS. However, for biosensing its use can be problematic since aggregates must be formed typically using salt, which are time dependent, fall out of solution, and generally do not provide good reproducibility. Thus, in this work, nanocages are analyzed and compared as an alternative to using gold colloid for quantifiable SERS biosensing. Scanning electron microscope (SEM) and transverse electron microscope (TEM) images are depicted for each material along with their extinction coefficients, aggregation properties, and SERS spectrum both with and without salt added. Overall, nanocages are shown to provide equivalent SERS enhancement without the need for salt induced aggregation and hence have the potential to be a better substrate for reproducible SERS biosensing.
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Optical Diagnostics and Sensing XV: Toward Point-of-Care Diagnostics