Plasmonic Detection of Carbohydrate‐Mediated Biological Events

Abstract

regulation of a variety of physiological and pathological processes, such as proliferation and adhesion, immune response, and cell differentiation. [8] The biological roles of carbohydrates as signaling effectors and recognition markers are associated to specific molecular recognition events in which proteins [9] or other carbohydrates [10] are involved. However, individual carbohydrate-based molecular interactions have been shown to be generally weak and, therefore, biomolecules usually present clusters of carbohydrates that interact cooperatively with their natural ligands (multivalent effect), thereby increasing the binding strength. [11] Interestingly, the multivalent carbohydrate presentation can be mimicked by man-made multivalent systems, which involve multiple synthetic oligosaccharides, [12][13][14][15][16][17] and have been used to address basic studies, but also as probe molecules and drugs. Mammalian cells are covered by a dense array of carbohydrates known as glycocalyx. The glycocalyx composition depends on the specific cellular state, and therefore it can provide information about diseases. For example, an increase of α-2,6-sialylation, fucosylation, and/or other tumor-associated carbohydrate antigens on the cellular membrane is considered as a biomarker of cancer progression, with diagnostic value. [18,19] In addition, oligosaccharides can be used as disease biomarkers for targeted therapy, and therefore the analysis and characterization of the composition of cellular glycans provide information of relevance to the diagnosis of several diseases. [20] Different strategies can be used to label glycans, including the use of covalent recognizing ligands (e.g., boronic acid), using specific carbohydrate-binding proteins, and via metabolic labeling.Plasmonics is based on the excitation of surface plasmons, that is, coherent oscillations of electrons induced by an electromagnetic radiation at metal-dielectric interfaces. [21] When the dimensions of plasmonic nanostructures are smaller than the wavelength of the incident light, the interaction between the electromagnetic field and surface charges results in nonpropagating oscillations denoted as localized surface plasmon resonances (LSPR). [22] LSPR frequencies in metal nanoparticles depend on their size, shape, organization, interparticle distance, and dielectric environment, ranging from the visible through the near-infrared (NIR). [23,24] A large volume of research has been devoted to the development of reliable methods for the preparation of plasmonic nanostructures with well-defined shape, size, and/or interparticle spacing, as basic components of various analytical applications. [25,26] Another important element, the surface chemistry of plasmonic The incorporation of nanomaterials in glycoscience research enables the design of highly selective and sensitive bioanalytical devices for the detection of disease-associated biomarkers. In particular, localized surface plasmon resonance (LSPR) and surface enhanced Raman scattering (SERS) spectroscopies ar...

Prospects of Surface-Enhanced Raman Spectroscopy for Biomarker Monitoring toward Precision Medicine

“…Many studies have reported the conjugation of plasmonic surfaces with different molecular probes that specifically react with target analytes, which are then detected through the vibrational changes derived from their interaction with pretagged Raman reporters. 168 − 172 Although such sensor configurations successfully repress signal overlap, they are limited to the established target-binding entities and can hardly be applied to multiplex detection, a valuable feature of SERS sensing ( Figure 5 a). A broadly applied strategy involves the use of self-assembled monolayers (SAM) to promote the binding of analytes with distinct affinities to SERS sensors and to minimize nonspecific fouling.…”

Glycan Nanobiosensors

“…The electrochemical readout was achieved by registering the chronoamperometric signal at −1.00 V. The device was able to detect viral particles with LOD of 8 HAU [ 80 ]. Older papers showing the application of plasmonic glycan-based devices based on AuNPs to the detection of lectins are summarized elsewhere [ 81 ].…”

Optimization of film over nanosphere substrate fabrication for SERS sensing of the allergen soybean agglutinin

“…Difference spectra show the clear emergence of new Raman bands upon SBA incubation at 500 cm −1 shift, 611 cm −1 shift, and 848 cm −1 shift. In fact, Asp, Gly, Asn, Leu, Arg, Phe, and Tyr are known to be the active amino acids in the SBA binding pocket, [51,52] and the bands at 611 and 848 cm −1 shift can both be attributed to tyrosine (likely the amino acid with the best Raman cross-section). It is important to note that binding of the protein to polymer depends on the overall Due to random polymer orientation and varying chain lengths on the surface of the FON, we determine that the protein has a high probability of binding to the polymer.…”