**Detection of Bacterial and Viral Pathogens Using Photonic Point-of-Care Devices**

#### **Peuli Nath** †**, Alamgir Kabir** †**, Somaiyeh Khoubafarin Doust, Zachary Joseph Kreais and Aniruddha Ray \***

Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA; Peuli.Nath@UToledo.Edu(P.N.);MdAlamgir.Kabir@rockets.utoledo.edu(A.K.);

Somaiyeh.KhoubafarinDoust@rockets.utoledo.edu (S.K.D.); Zachary.Kreais@rockets.utoledo.edu (Z.J.K.)

**\*** Correspondence: Aniruddha.ray@utoledo.edu; Tel.: +1-(419)-530-4787

† These authors contributed equally.

Received: 7 September 2020; Accepted: 15 October 2020; Published: 19 October 2020

**Abstract:** Infectious diseases caused by bacteria and viruses are highly contagious and can easily be transmitted via air, water, body fluids, etc. Throughout human civilization, there have been several pandemic outbreaks, such as the Plague, Spanish Flu, Swine-Flu, and, recently, COVID-19, amongs<sup>t</sup> many others. Early diagnosis not only increases the chance of quick recovery but also helps prevent the spread of infections. Conventional diagnostic techniques can provide reliable results but have several drawbacks, including costly devices, lengthy wait time, and requirement of trained professionals to operate the devices, making them inaccessible in low-resource settings. Thus, a significant effort has been directed towards point-of-care (POC) devices that enable rapid diagnosis of bacterial and viral infections. A majority of the POC devices are based on plasmonics and/or microfluidics-based platforms integrated with mobile readers and imaging systems. These techniques have been shown to provide rapid, sensitive detection of pathogens. The advantages of POC devices include low-cost, rapid results, and portability, which enables on-site testing anywhere across the globe. Here we aim to review the recent advances in novel POC technologies in detecting bacteria and viruses that led to a breakthrough in the modern healthcare industry.

**Keywords:** infectious diseases; diagnostics; point-of-care devices; microfluidics; plasmonics; smartphone; lensless imaging
