SERS biosensors for liquid biopsy towards cancer diagnosis by detection of various circulating biomarkers: current progress and perspectives.

Liquid biopsy has emerged as a promising non-invasive strategy for cancer diagnosis, enabling the detection of various circulating biomarkers, including circulating tumor cells (CTCs), circulating tumor nucleic acids (ctNAs), circulating tumor-derived small extracellular vesicles (sEVs), and circulating proteins. Surface-enhanced Raman scattering (SERS) biosensors have revolutionized liquid biopsy by offering sensitive and specific detection methodologies for these biomarkers. This review comprehensively examines the application of SERS-based biosensors for identification and analysis of various circulating biomarkers including CTCs, ctNAs, sEVs and proteins in liquid biopsy for cancer diagnosis. The discussion encompasses a diverse range of SERS biosensor platforms, including label-free SERS assay, magnetic bead-based SERS assay, microfluidic device-based SERS system, and paper-based SERS assay, each demonstrating unique capabilities in enhancing the sensitivity and specificity for detection of liquid biopsy cancer biomarkers. This review critically assesses the strengths, limitations, and future directions of SERS biosensors in liquid biopsy for cancer diagnosis.

Emerging Microfluidic Devices for Sample Preparation of Undiluted Whole Blood to Enable the Detection of Biomarkers.

Blood testing allows for diagnosis and monitoring of numerous conditions and illnesses; it forms an essential pillar of the health industry that continues to grow in market value. Due to the complex physical and biological nature of blood, samples must be carefully collected and prepared to obtain accurate and reliable analysis results with minimal background signal. Examples of common sample preparation steps include dilutions, plasma separation, cell lysis, and nucleic acid extraction and isolation, which are time-consuming and can introduce risks of sample cross-contamination or pathogen exposure to laboratory staff. Moreover, the reagents and equipment needed can be costly and difficult to obtain in point-of-care or resource-limited settings. Microfluidic devices can perform sample preparation steps in a simpler, faster, and more affordable manner. Devices can be carried to areas that are difficult to access or that do not have the resources necessary. Although many microfluidic devices have been developed in the last 5 years, few were designed for the use of undiluted whole blood as a starting point, which eliminates the need for blood dilution and minimizes blood sample preparation. This review will first provide a short summary on blood properties and blood samples typically used for analysis, before delving into innovative advances in microfluidic devices over the last 5 years that address the hurdles of blood sample preparation. The devices will be categorized by application and the type of blood sample used. The final section focuses on devices for the detection of intracellular nucleic acids, because these require more extensive sample preparation steps, and the challenges involved in adapting this technology and potential improvements are discussed.

Changes in glycans on platelet microparticles released during storage of apheresis platelets are associated with phosphatidylserine externalization and phagocytosis.

BACKGROUND: Platelets shed platelet microparticles (PMP) when activated or stored. As the removal of sialic acid (desialylation) promotes platelet uptake and clearance from the circulation, similar mechanisms for PMP uptake were hypothesized. The aim of the study was to investigate the role of surface glycans in the in vitro uptake of PMP from stored platelet components. STUDY DESIGN AND METHODS: Apheresis platelet components were stored in 40% plasma/60% SSP+ and sampled on day 1, 5, and 7 post-collection. PMP were characterized by staining with annexin-V (AnV) for phosphatidylserine (PS)-exposure, CD41 antibody, and fluorescently labeled glycan-binding lectins using flow cytometry. The procoagulant function of PMP following desialylation by neuraminidase treatment was assessed by AnV binding and a procoagulant phospholipid assay. PMP were isolated and stained with Deep Red, and phagocytosis by HepG2 cells was measured. Isolated PMP were deglycosylated with neuraminidase and galactosidase to assess the involvement of glycans in mediating phagocytosis. RESULTS: While the overall platelet surface glycan profile was unchanged during storage, PS+ platelets were sialylated, indicating different glycoproteins were changed. In contrast, sialic acid was removed from PS+ and CD41+ PMP, which specifically lost α-2,3-linked sialic acid during platelet storage. PMP were phagocytized by HepG2 cells, and PMP from platelets stored for 7 days were phagocytized to a lesser extent than on day 1. Desialylation by neuraminidase induced PS-exposure on PMP, decreased PPL clotting time, and increased PMP phagocytosis. CONCLUSION: PMP glycans change during platelet storage. Desialylation influences the procoagulant function of PMP and phagocytosis by HepG2 cells.