Surface Enhanced Raman Spectroscopy (SERS) is a very promising vibrational technique able to provide specific molecular information that could have a major impact in a plethora of biomedical applications. Amongst these applications, SERS-based early cancer detection could represent a breakthrough. Being a surface technique, SERS requires the presence of a suitable plasmonic substrate able to generate specific, enhanced and reproducible spectra when using an excitation laser line ranging from visible to near infra-red domain. The major obstacle that hampers its implementation in clinical practice is the synthesis of a proper plasmonic suitable for measurements on biofluids. In this paper we propose a new approach for the synthesis of a solid SERS substrate using as building blocks spherical silver nanoparticles purified and concentrated using the Tangential Flow Filtration (TFF) method. The capacity of the here proposed Silver Solid Plasmonic Substrate (SSPS) to generate reproducible and enhanced Raman signals in a manner that can allow cancer detection has been tested on blood plasma samples collected from 37 healthy donors and 34 breast cancer (BC) patients. The SER spectra collected from the two groups have been analyzed by means of Principal Component Analysis (PCA) combined with Linear Discriminant Analysis (LDA). Our results allowed the discrimination between the healthy donors and breast cancer (BC) patients with very high sensitivity and specificity (90% sensitivity and 89% specificity).The here reported diagnostic accuracy of 89%, obtained by performing SERS measurements directly on blood plasma samples without performing any other purification or deproteinization step, is a direct consequence of SSPSs ability to generate diagnostic relevant spectral information. Our results suggest that this type of solid substrates could be also employed for the detection of other types of cancer or other diseases.

Solid plasmonic substrates synthesized using TFF purified colloidal silver for cancer detection by means of SERS analysis of blood plasma

2019 Fall National Meeting

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