Lateral Flow Assays (LFAs) have become the foundation of point-of-care (POC) diagnostics, valued for their user-friendly format, cost-effectiveness, and rapid turnaround time. However, despite their widespread success, most notably in pregnancy testing and infectious disease monitoring, conventional colorimetric LFAs often suffer from insufficient sensitivity, limiting their utility for the early-stage detection of low-abundance biomarkers. This review provides a critical analysis of recent strategies have been developed to improve the sensitivity of these assays. Enhancement strategies are systematically classified into six distinct domains: (i) flow modulation techniques that optimise reaction kinetics; (ii) sample preconcentration methods; (iii) advanced signal transduction reporters beyond traditional gold nanoparticles; (iv) chemical signal amplification including nanozyme and enzymatic catalysis; (v) structural strategies for maximising label accumulation; and (vi) the engineering of aptamers as programmable recognition elements. Special emphasis is placed on ”reagent-free” and ”equipment-free” innovations that boost performance without compromising the inherent simplicity of the device. Finally, the emerging transition from passive biological selection to active molecular engineering is discussed, outlining the future trajectory of ultra-sensitive next-generation LFAs.

Cholesterol is currently one of the main biomarkers for the assessment of cardiovascular diseases risk, with low-density and high-density lipoprotein measured in the global cardiovascular risk assessment. Nevertheless, the detection of these molecules still relies on traditional methods, which can be resource intensive. Research has been focusing on developing more rapid techniques for cholesterol detection, often emphasizing technologies suitable for point-of-care use to facilitate screening and diagnosis in decentralized or underserved settings. This review begins with an overview of cholesterol metabolism and biology, followed by an in-depth examination of the various sensor technologies reported in the literature for detecting cholesterol in its different forms, including free (non-esterified), esterified, and lipoprotein-bound, ranging from enzymatic to non-enzymatic approaches, such as molecularly imprinted polymers. The functioning mechanism, advantages, and limitations of each type of sensors are discussed, leading to the final recommendations. Enzymatic sensors could prove preferrable in the detection of free or esterified cholesterol, given their selectivity, while molecularly imprinted polymers seem to have the edge in the detection of lipoproteins, with different studies demonstrating their applicability in human serum.

At-home testing of glucose levels is crucial for safe monitoring of a variety of diseases, such as pancreatitis, psoriasis, cirrhosis, acute myocardial infarction, and, of course, diabetes. Current blood tests are invasive, leading to the research of alternative biofluids such as saliva, tears, and sweat. Nevertheless, such fluids are limited in quantity and contains various interfering molecules, posing stringent technological requirements. In this study, a simple paper-based glucose sensor is designed by using the conductive polymer poly(3,4-ethylene-dioxythiophene) polystyrene sulfonate (PEDOT:PSS) and a bi-enzymatic solution of Horseradish Peroxidase (HRP) and Glucose Oxidase (GOx). Unlike most electrochemical glucose sensors, this sensor employs a chemiresistive mechanism, allowing simple configurations, low costs, and easy signal measurements. The designed sensor demonstrates a working range suitable for various biofluid analysis, e.g., saliva, with a limit of detection of 1.1 µM and a linear detection range of 102 – 104 µM while only requiring 40 µL sample volume. Detection in whole artificial saliva is also carried out to demonstrate the sensor applicability. The limited analyte volume required, and the suitable detection range and limit of detection achieved by this sensor make it an excellent candidate for developing a non-invasive, at home glucose meter.