Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics (CNBP), Faculty of Engineering, The University of New South Wales, Sydney, 2052, Australia; Australian Centre for NanoMedicine, The University of New South Wales, Sydney, 2052, Australia; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR, China. Electronic address: [Email]
Paper-based analytical devices (PADs) are very popular for point-of-care diagnostics, which provide a fast, cost-effective and possible multiplexed detection of a spectrum of molecules. They have been matching forward proudly to contribute to the modern analytical science and life science. Accompanying with their advantages and huge potentials, low detection sensitivity is continuing to challenge the application of PADs from bench to bedside. In order to improve the sensitivity and enhance the signal readout, variable signal amplification strategies have been investigated and applied for PADs. In this review, we have firstly classified formats of PADs according to the engineering design. Advances for improving sensitivity of PADs in recent five years are then summarised according to three popular types of signal amplification strategies (nanomaterial based, nucleic acid based, and engineering of PADs based). Pros and cons of each signal amplification approach have been discussed accordingly. Finally, the future perspectives of PADs are proposed.