Nanomaterial-enabled portable paper-based colorimetric and fluorometric devices: Progress in point-of-care diagnosis

This review paper comprehensively explores recent advancements in the development of colorimetric and fluorometric paper-based analytical devices (PADs) for rapid point-of-care diagnosis of specific disease biomarkers. The paper elucidates the principles of colorimetry and fluorometry, focusing on their application in the detection of various biomolecules. Notably, metal nanoparticles (NPs) and quantum dots (QDs) emerge as versatile sensing probes in these platforms. The fabrication of nanomaterials (NMs) on paper substrates is extensively discussed, covering techniques such as dip-coating, drop-casting, wax printing, inkjet printing and screen printing. The integration of PADs with portable devices is explored, including gray scale and RGB measurements using desktop scanners, smartphones and color detector apps for enhanced colorimetric and fluorometric analysis. The application of PADs with metal NPs for the detection of a wide array of biomolecules is highlighted. The versatility of these devices is demonstrated in detecting nucleic acids, proteins, amino acids, bio thiols, urea, uric acid, antigens, antibodies, glucose, creatinine, bilirubin, vitamins and bacteria. The potential for point-of-care diagnosis in diverse healthcare settings is underscored, emphasizing the simplicity, cost-effectiveness and rapidity of these paper-based diagnostic platforms. This review provides an overview of the NMs-enabled colorimetric and fluorometric PADs, offering insights into the fabrication techniques, integration with portable devices and diverse applications in the field of biomarker detection. The amalgamation of metal nanoparticles and quantum dots with paper-based devices holds promising prospects for advancing point-of-care diagnostics of specific disease biomarkers.