Publication details

Detection of protein biomarkers using lateral flow immunoassays based on photon-upconversion nanoparticles

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Year of publication 2023
Type Conference abstract
Description Rapid and sensitive detection of protein biomarkers is essential for the early diagnosis and prevention of different diseases. Due to the fast and easy analysis, lateral flow immunoassays (LFIAs) are currently becoming one of the most popular forms of tests for the detection of various analytes. The high selectivity of LFIAs is given by the high specificity of antibodies. Furthermore, little to no laboratory equipment is required to perform these assays, making them suitable for point-of-care testing (PoCT). Gold nanoparticles (AuNPs) are generally used as a label for LFIA analysis, allowing for naked-eye readout. However, even though AuNP-based LFIAs are highly convenient for PoCT testing, the sensitivity is often insufficient to detect low-abundance biomarkers. Thus, different kinds of nanomaterials are being studied for use as alternative labels. Our work focused on the application of photon-upconversion nanoparticles (UCNPs) as a label in LFIAs. UCNPs are lanthanide-doped nanocrystals exhibiting anti-Stokes luminescence; they can be excited by the near-infrared laser and detected in the visible region without optical background interferences in biological samples. UCNPs composed of NaYF4 doped with Yb3+ and Er3+ were synthesized and conjugated with specific antibodies via copper-catalyzed click chemistry. Such conjugates enabled the development of LFIA assays for the detection of protein biomarkers human serum albumin (HSA) and prostate-specific antigen (PSA). Several optimization steps were carried out. The biggest impact was observed in the case of selection of suitable membranes for designing the LFIA strips, addition of of methanol to buffer for immobilization of antibodies, and addition of sucrose to buffer for incubation of UCNP conjugate. So far, UCNP-based LFIA has been successfully used for detecting HSA and PSA from buffers, proving that UCNPs are a convenient alternative to AuNPs. Moreover, the preliminary data demonstrate great potential for real sample analysis in various body fluids (e.g., blood serum or urine). The UCNP-based LFIAs can thus enable the sensitive detection of protein biomarkers and other clinically relevant analytes, combining simplicity of the assay with high sensitivity.
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