The development of biosensing tools and lab-on-chip devices is crucial for diagnostics because they enable rapid, accurate, and on-site detection of diseases, reducing the need for complex laboratory infrastructure and making healthcare accessible in remote areas. By integrating multiple laboratory functions onto a single chip, they significantly lower the costs and time associated with diagnostic processes. Such tools are pivotal in managing outbreaks and epidemics, providing essential data for timely public health responses. These technologies can also facilitate personalized medicine through the real-time monitoring of health conditions, allowing for tailored treatments.

We are developing sensitive and easy-to-implement fluorescence diagnostic assays for low resource settings. Our assay development builds on our know-how and diverse expertise in optics, microfluidics, biosensors and engineering.  For example, we have demonstrated how DNA aptamer based sensing of proteins can be implemented using protein induced fluorescence enhancement that is rapid, sensitive and modular (Umrao, et al. Sens. & Actuators: Chem. 2018 ). Similarly, we developed a sensitive smartphone assay for antibiotic (kanamycin) detection that takes advantage of the ratiometric nature of the FRET signature (Umrao, et al. RSC Advances 2019 ). We also developed a quantitative variant of the isothermal nucleic acid amplification technique, Recombinase Polymerase Amplification (qeRPA) that substantially reduces the hurdles for qPCR based diagnostics while providing comparable results (Priyanka and Roy, Anal Chem 2022).

To push the limits of non-optical detection of cells, we have developed a low-cost disposable Lab-On-Chip device for cell-in-droplet counting. We established a novel multi-layer device fabrication methodology that uses fusible alloy to replace metal microelectrodes but demonstrates high sensitivity for cell impedance measurements in a flow cytometry configuration (Panwar and Roy, MicroE Engineering  2019). We also developed a new framework to predict microdroplet size in two phase systems that effectively captures the transition from squeezing and dripping regimes of droplet generation, providing essential insights into the design requirements for suction-driven droplet generation (Panwar and Roy, Microfluidics and Nanofluidics 2024).

1. S Umrao, V Jain, Anusha, B Chakraborty, R Roy, "Protein-induced fluorescence enhancement as aptamer sensing mechanism for thrombin detection." Sensors and Actuators B: Chemical 267: 294-301 doi:10.1016/j.snb.2018.04.039 (2018) 

2. S Umrao, Anusha S, V Jain, B Chakraborty, R Roy, "Smartphone-based kanamycin sensing with ratiometric FRET" RSC Advances, 9, 6143-6151 doi:10.1039/C8RA10035G (2019) 

3. J Panwar and R Roy, "Fusible alloy 'in-contact' microelectrodes: a rapid and economic microfabrication alternative for microfluidic impedance cytometry" MicroE Engineering, doi: https://doi.org/10.1016/j.mee.2019.111010 (2019)

4. Priyanka V, and R Roy, "Nucleic acid quantification with amplicon yield in recombinase polymerase amplification" Analytical Chemistry, doi.org/10.1021/acs.analchem.2c02810 (2022)

5. J Panwar and R Roy, "Modified capillary number to standardize droplet generation in suction driven microfluidics" Microfluidics and Nanofluidics  (2024, in press)