Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-Coated Polystyrene Cores—Assessment of the Binding Behavior to Cancer Cells

Abstract

Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA. However, these protein molecules are usually expensive and easily denatured, which calls for the development of alternative glycan-specific receptors and cell imaging technologies. In this study, SA-imprinted fluorescent core-shell molecularly imprinted polymer particles (SA-MIPs) were employed to recognize SA on the cell surface of cancer cell lines. The SA-MIPs improved suspensibility and scattering properties compared with previously used core-shell SA-MIPs. Although SA-imprinting was performed using SA without preference for the α2,3- and α2,6-SA forms, we screened the cancer cell lines analyzed using the lectins Maackia Amurensis Lectin I (MAL I, α2,3-SA) and Sambucus Nigra Lectin (SNA, α2,6-SA). Our results show that the selected cancer cell lines in this study presented a varied binding behavior with the SA-MIPs. The binding pattern of the lectins was also demonstrated. Moreover, two different pentavalent SA conjugates were used to inhibit the binding of the SA-MIPs to breast, skin, and lung cancer cell lines, demonstrating the specificity of the SA-MIPs in both flow cytometry and confocal fluorescence microscopy. We concluded that the synthesized SA-MIPs might be a powerful future tool in the diagnostic analysis of various cancer cells.

Structure and Biological Properties of Ribosome-Inactivating Proteins and Lectins from Elder (Sambucus nigra L.) Leaves

“…Therefore, they have been used as the enzymatic component of immunotoxins and other conjugates directed against tumor cells [3,11]. Due to their specificity for the α2,6-linked sialic acid, SNAI from the bark of S. nigra and SSA from the bark of S. sieboldiana are used in highly diverse biomedical applications, such as diagnosis by ELISA [32,33], histochemistry [34,35], confocal fluorescence microscopy [36], microarrays [37], and new therapeutic strategies [38]. Elderberry RIPs have also been used in agriculture to obtain transgenic plants resistant to viruses [39,40] and insects [41,42].…”

Molecularly Imprinted Nanomaterials with Stimuli Responsiveness for Applications in Biomedicine

“…In the field of MIP-NP fluorescence imaging, the selection of efficient detection probes is very important [ 139 ]. Suitable luminescent imaging components, such as quantum dots (QDs) [ 140 , 141 , 142 ], carbon dots (CDs) [ 143 ], organic dye-doped polymers or silica NPs [ 144 , 145 ], conjugated polymers (CPs) [ 146 , 147 ], etc., and non-luminescent imaging modalities, such as gold NPs [ 148 ], silver NPs [ 149 ], radioisotope-enriched NPs and iron oxide NPs, are chosen to achieve different goals. Introductions to related materials can be found in other works in the literature.…”

Molecularly imprinted polymers (MIPs): emerging biomaterials for cancer theragnostic applications

“…Interestingly, this feature allows for the capture and release of cancer cells in both culture media and real blood samples. Beyer et al also focused on the detection of SA [ 115 ]. The team developed an SA-imprinted fluorescent core–shell sensing probe.…”