Label-free surface-enhanced Raman spectroscopy of biofluids: fundamental aspects and diagnostic applications

Abstract

In clinical practice, one objective is to obtain diagnostic information while minimizing the invasiveness of the tests and the pain for the patients. To this end, tests based on the interaction of light with readily available biofluids including blood, urine, or saliva are highly desirable. In this review we examine the state of the art regarding the use of surface-enhanced Raman spectroscopy (SERS) to investigate biofluids, focusing on diagnostic applications. First, a critical evaluation of the experimental aspects involved in the collection of SERS spectra is presented; different substrate types are introduced, with a clear distinction between colloidal and non-colloidal metal nanostructures. Then the effect of the excitation wavelength is discussed, along with anomalous bands and artifacts which might affect SERS spectra of biofluids. The central part of the review examines the literature available on the SERS spectra of blood, plasma, serum, urine, saliva, tears, and semen. Finally, diagnostic applications are critically discussed in the context of the published evidence; this section clearly reveals that SERS of biofluids is most promising as a rapid, cheap, and non-invasive tool for mass screening for cancer.

Hierarchical zwitterionic modification of a SERS substrate enables real-time drug monitoring in blood plasma

“…Therapeutic drugs are typically excellent candidates for SERS detection, as ∼95% of marketed drugs contain a conjugated ring system (such as a benzene ring)8, which tend to produce the relatively large Raman scattering cross-sections necessary for high sensitivity. To date, several drugs have been directly identified in saliva and urine using SERS, but blood samples require separation and chromatographic purification before SERS detection9101112. The Raman-scattering enhancement seen in SERS decreases sharply when analytes are too far from a SERS-active surface1314.…”

Fructose and Pectin Detection in Fruit-Based Food Products by Surface-Enhanced Raman Spectroscopy

“…Over the past few decades Surface-Enhanced Raman Spectroscopy (SERS) has been fruitfully used for investigating materials with weak Raman signals and for the detection and study of various molecules down to the single-molecule level [1,2,3,4,5]. SERS combines the advantages of Raman spectroscopy such as its high specificity, and the ability to identify a given molecular species in the presence of many other chemicals, with the relevant Raman signal enhancement enabled by nanosized metallic materials.…”

Unveiling NIR Aza‐Boron‐Dipyrromethene (BODIPY) Dyes as Raman Probes: Surface‐Enhanced Raman Scattering (SERS)‐Guided Selective Detection and Imaging of Human Cancer Cells

“…[10][11][12][13] It possessess ingle-molecule detection that could be applied to noble-metal structureso rs ubstrates (typically ag old or silver nanoparticles). [17,18] For instance, al abel-freeb lood test method basedo nS ERS was reportedf or nasopharyngeal,gastric and colorectal cancer detection. [14][15][16] In recenty ears, successful results have been achieved for cancer biomarker detection in blood, saliva and serum samples, and of target cells by means of SERS fingerprinting.…”