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 … Show more
“…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.…”
Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive analytical technique with molecular specificity, making it an ideal candidate for therapeutic drug monitoring (TDM). However, in critical diagnostic media including blood, nonspecific protein adsorption coupled with weak surface affinities and small Raman activities of many analytes hinder the TDM application of SERS. Here we report a hierarchical surface modification strategy, first by coating a gold surface with a self-assembled monolayer (SAM) designed to attract or probe for analytes and then by grafting a non-fouling zwitterionic polymer brush layer to effectively repel protein fouling. We demonstrate how this modification can enable TDM applications by quantitatively and dynamically measuring the concentrations of several analytes—including an anticancer drug (doxorubicin), several TDM-requiring antidepressant and anti-seizure drugs, fructose and blood pH—in undiluted plasma. This hierarchical surface chemistry is widely applicable to many analytes and provides a generalized platform for SERS-based biosensing in complex real-world media.
“…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.…”
Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive analytical technique with molecular specificity, making it an ideal candidate for therapeutic drug monitoring (TDM). However, in critical diagnostic media including blood, nonspecific protein adsorption coupled with weak surface affinities and small Raman activities of many analytes hinder the TDM application of SERS. Here we report a hierarchical surface modification strategy, first by coating a gold surface with a self-assembled monolayer (SAM) designed to attract or probe for analytes and then by grafting a non-fouling zwitterionic polymer brush layer to effectively repel protein fouling. We demonstrate how this modification can enable TDM applications by quantitatively and dynamically measuring the concentrations of several analytes—including an anticancer drug (doxorubicin), several TDM-requiring antidepressant and anti-seizure drugs, fructose and blood pH—in undiluted plasma. This hierarchical surface chemistry is widely applicable to many analytes and provides a generalized platform for SERS-based biosensing in complex real-world media.
“…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.…”
Surface-Enhanced Raman Spectroscopy (SERS) enables the investigation of samples with weak specific Raman signals, such as opaque samples, including fruit juices and pulp. In this paper, biological apple juices and apple/pear pulp have been studied in order to evidence the presence of fructose and pectin, which are components of great relevance for quality assessment of these kinds of products. In order to perform SERS measurements a low-cost home-made substrate consisting of a glass slide decorated with 30-nm-sized gold nanoparticles has been designed and used. By employing a conventional micro-Raman spectroscopy set-up and a suitable data treatment based on “wavelet” denoising algorithms and background subtraction, spectra of pectin and fructose with clear Raman features have been obtained. The results have confirmed the potential of SERS in the food industry for product characterization, also considering the low-cost and the relative ease of the fabrication process of the employed SERS substrate.
“…[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.…”
The development of new Raman reporters has attracted immense attention in diagnostic research based on surface enhanced Raman scattering (SERS) techniques, which is a well established method for ultrasensitive detection through molecular fingerprinting and imaging. Herein, for the first time, we report the unique and efficient Raman active features of the selected aza-BODIPY dyes 1-6. These distinctive attributes could be extended at the molecular level to allow detection through SERS upon adsorption onto nano-roughened gold surface. Among the newly revealed Raman reporters, the amino substituted derivative 4 showed high signal intensity at very low concentrations (ca. 0.4 μm for 4-Au). Interestingly, an efficient nanoprobe has been constructed by using gold nanoparticles as SERS substrate, and 4 as the Raman reporter (4-Au@PEG), which unexpectedly showed efficient recognition of three human cancer cells (lung: A549, cervical: HeLa, Fibrosarcoma: HT-1080) without any specific surface marker. We observed well reflected and resolved Raman mapping and characteristic signature peaks whereas, such recognition was not observed in normal fibroblast (3T3L1) cells. To confirm these findings, a SERS nanoprobe was conjugated with a specific tumour targeting marker, EGFR (Epidermal Growth Factor Receptor), a well known targeted agent for Human Fibrosarcoma (HT1080). This nanoprobe efficiently targeted the surface marker of HT1080 cells, threreby demonstrating its use as an ultrasensitive Raman probe for detection and targeted imaging, leaving normal cells unaffected.
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