**6. Conclusions**

In this review, we described some recent point-of-care technologies incorporating plasmonics, microfluidics, smartphone imagers, and lensless microscopes for simple, sensitive, rapid 'on-site' detection of pathogens (summarized in Table 1). Several examples covering a wide range of techniques such as immunoassays (ELISA, fluorescence, etc.) and nucleic acid amplification were discussed. Although the POC devices have been able to overcome some of the major drawbacks associated with conventional diagnostic technologies, particularly in terms of cost, throughput, and portability, there are still ways to go. A huge amount of e ffort needs to be dedicated in order to improve their sensitivity, specificity, ease of use, and storage, which will facilitate the use of these diagnostic techniques everywhere around the globe daily. These advanced POC devices hold the potential to

revolutionize the diagnosis of the viral and bacterial pathogens, especially in resource-limited settings, thereby saving countless more lives.


**Table 1.** A list of commonly used point-of-care (POC) technologies for the detection of some of the highly infectious bacterial and viral pathogens.

**Author Contributions:** Conceptualization, A.R.; methodology, P.N., A.K., S.K.D., Z.J.K., and A.R.; writing—original draft preparation, P.N., A.K., S.K.D., Z.J.K., and A.R.; writing—review and editing, P.N. and A.R.; supervision, A.R.; All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the University of Toledo startup funds (2019).

**Acknowledgments:** The authors would like to thank Ms. Valentina Valentina Campos Yanez for the schematic of the smartphone reader in Figure 1.

**Conflicts of Interest:** The authors declare no conflict of interest.
