Paper-based point of care diagnostics for cancer biomarkers

Early detection of cancers is key to a better prognosis. Advanced proteomics and genomic detection techniques offer great specificity and sensitivity, however, delayed symptomatic detection, cost, and patient-incompliant sample procurement limit routine cancer diagnosis, thus affecting treatment opportunities and patient survival. The revolutionary impact of paper-based COVID-19 antigen home test kits highlighted the importance of affordable routine diagnosis in tackling pandemics. Therefore, inexpensive, user-friendly, and sensitive paper-based biosensors can prove to be a game changer in the management of cancer. Even though the fabrication of paper-based biosensors is easy and inexpensive, their compromised sensitivity requires significant improvement for effective diagnosis. This review comprehensively and systemically focuses on highlighting the impactful advancements that occurred over the past 10 years to improve the sensitivity at different levels of paper-based detection i.e. advancements in paper chemistry, assay type, detection technique, and signal enhancement. A detailed focus has also been provided on the impact of advanced nanomaterials (classified into inorganic, organic, and amalgamation of both) in enhancing analyte detection, signal amplification, signal transmission, and signal readout to develop point-of-care systems with fast interpretation, better reliability, specificity, biocompatibility, and low detection limits for the early paper-based detection of cancer. Moreover, a specific section on the types of samples employed for cancer detection, comprehensive tabulation of validated biosensors with clinical samples, their current challenges, and future prospects can help disseminate extensive information in driving the research forward in low-cost diagnosis of cancer. Advancements in assay design, detection techniques, signal transduction and enhancement strategies using smart nanomaterials.