« SPECTROSCOPY “
By utilizing these 2 techniques in tandem, this method has the potential to help revolutionize early cancer detection and, as a result, save lives.
In the upcoming months, we plan to further increase the sensitivity of this device by having the pSERS nanoparticles functionalized with beta-cyclodextrin, and using a dip approach to take advantage of the capillary eff ect for concentration of the sample. In addition to the pSERS substrates, we will also continue to refi ne the Raman spectrometer in parallel. Lastly, we are working in collaboration with a team at the University of Waterloo to develop a software interface which will allow for an operator to get a simple “red light/yellow light/green light” readout from a single click. During the course of this collaboration we are also planning to develop a wireless connectivity system which will allow the data from the instrument to instantaneously be uploaded to a clinician’s smartphone or tablet as well as electronic medical records systems.
shown in Figure 4(b) with a 12VDC power connector and USB interface on the back of the unit. This unit was able to easily detect the 740-cm-1 vibrational band of N-acetylamantadine at concentrations of 1 µg/mL, as shown in Figure 5, without any functionalization of the substrate or concentration methodology (ie, the dip approach). Figure 5 shows the spectrum collected from the unit with 2 µL of the analyte pipetted on the substrate, with an additional 2 µL of 0.1% HCL applied after drying.
Final T oughts
The approach detailed above indicates the potential for detection of pre-visible/pre-symptomatic cancer, by detecting the chemical signature of the acetylation process corresponding to the upregulation of SSAT1 in the presence of cancer. Additional research is still needed to prove equivalency between the traditional wet chemistry methods currently being utilized in clinical investigations and the Raman spectroscopy methods proposed in this article, but it currently shows the greatest potential for mass deployment of this technology. This is especially true in the developing world where access to advanced laboratory space and sample preparation (such as drying) is extremely limited.
Currently, we envision the Raman spectroscopic method of quantitating N-acetylamantadine in urine to be used as a clinical screening tool.
In this case, the mass deployed Raman system Figure 4. (a) pSERS slide holder with adjustable focus, and
(b) Class I Raman spectrometer for analysis of slide-mounted pSERS substrates.
would be used to identify the need for more detailed analysis via wet chemistry techniques such as LC-MS/MS and/or traditional pathology. By utilizing these 2 techniques in tandem, this method has the potential to help revolutionize early cancer detection and, as a result, save lives.
References
1. Lozano Diz E and Thomas RJ. Portable Raman for raw material QC: What’s the ROI? Pharmaceutical Manufacturing Magazine. 2013;12(1):30-34. Available at: http://www.
pharmamanufacturing.com/articles/2013/006/. Accessed November 18, 2014.
2. Diehl B, Chen CS, Grout B, et al. An implementation perspective on handheld Raman spectrometers for the verifi cation of material identity. Eur Pharm Rev. Non-destructive Materials Identifi cation Supplement. 2012;17(5):3–8. Available at: http://www.
europeanpharmaceuticalreview.com/wp-content/uploads/Raman-Supplement-2012. pdf. Accessed November 18, 2014.
Figure 5. pSERS Raman spectrum of 2 µg of N-acetylamantadine measured using the system shown in Figure 4.
3. Yang D and Thomas RJ. The benefi ts of a high-performance, handheld Raman spectrometer for the rapid identifi cation of pharmaceutical raw materials. Am Pharm Rev. 2012;15(7):S22-S26. Available at:
http://www.americanpharmaceuticalreview. com/Featured-Articles/126738-The-Benefi ts-of-a-High-Performance-Handheld-Raman- Spectrometer-for-the-Rapid-Identifi cation-of-Pharmaceutical-Raw-Materials/. Accessed November 18, 2014.
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