Selected Publications & Preprints

TB is the number one killer infectious disease in the world and its control and elimination is severely limited by diagnostic challenges as up to 30-40% TB patients remain undiagnosed. In this preprint we report the first non-sputum point-of-care (POC) diagnostic for TB using antibody Fc features from a drop of blood that can diagnose active TB and distinguish it from latent TB infection. A new multivariate antibody Fc biomarker and a method for its POC measurement using a novel multimeric molecular probe and a cellphone-read silver metallization based assay are described. Performance matching or exceeding WHO target product profiles is reported across training and testing cohorts.

Schistosomes are parasitic flatworms that pose a substantial disease burden affecting more than 200 million people worldwide. Current antibody tests cannot distinguish between active and past infections. In this paper we report a multiplexed antibody Fc profiling approach that uses interpretable machine learning to distinguish different stages of disease. Comparing healthy and infected individuals across two human cohorts from Brazil and Kenya revealed previously uncharacterized signatures of active disease, including increased Fc receptor binding and specific antibody glycoforms.

In the News (selected):

TB is highly heterogeneous and yet TB infection detection currently uses Interferon Gamma Release Assays (IGRA) that measure a single cytokine. Multiplexed cytokine measurement improves TB detection and staging yet remains inaccessible. Here we report an inexpensive, high-throughput platform for multiplexed POC cytokine detection using amplified enzymatic silver metallization on common plastic substrates. This enables dry, cellphone-readable measurement of multiple TB-relevant cytokines (IFN-γ, IL-2, and TNF-α) from less than 5 µL of stimulated blood sample, reaching clinically relevant sub-picomolar sensitivity and demonstrating measurement of multiplexed cytokine fingerprints from IGRA supernatants from a TB-endemic setting.

Smartphone-enabled multiplexed biomarker detection

Here we developed a low-cost, portable multiplexed biosensing platform that uses enzymatic silver metallization and cellphone-based computer vision to quantify multiple biomarkers from sub-microliter clinical samples. Applied to COVID-19 serology, the platform distinguished infection- and vaccine-associated antibody fingerprints, demonstrating a path toward inexpensive, high-throughput, POC immune profiling. The OpenCV based cellphone app is available as open source software here. This paper is the first report of what has since become our lab’s workhorse inexpensive multiplexed optical detection technologies for various POC diagnostic applications.

Direct electrical readout of multiplexed immune biomarkers

Here we developed a new point-of-care biosensing approach that converts biomarker binding directly into a dry, conductive silver layer on microelectrode arrays. By combining enzyme-amplified metallization with nanostructured catalytic surfaces, the platform enables sensitive, multiplexed, optics-free electronic detection from a single drop of sample. Applied to COVID-19 serology, it distinguished immune signatures of prior infection and vaccination using a portable, cellphone-interfaced reader. This paper is the first report of what has since become our lab’s workhorse inexpensive electronic detection technology for various POC diagnostic applications.

‍ ‍In the News:


Publications, Preprints & Conference Presentations

2026

2025

2024

2023

2022

2021

  • Multiplexed Point-of-Care Electrical Detection of COVID-19 Biomarkers Using Enzymatically Amplified Metallization on Nanostructured Surfaces

    N. Rafat, H. Zhang, J. Rudge, Y. Kim, A. Sarkar, 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS 2021), Palm Springs, USA, October 2021 [Talk]

  • Electronic Immunoassays Using Enzymatically Amplified Metallization on Microparticles

    J. Rudge, N. Rafat, M. Hoyle, A. Sarkar, 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS 2021), Palm Springs, USA, October 2021 [Poster]

  • Multiplexed Antibody Profiling Predicts Outcome in Severe COVID-19

    S. P. Peddireddy, S. Rehman, H. Singh, J. Das, A. Sarkar, 2021 Annual Meeting of the Biomedical Engineering Society (BMES2020). Orlando, USA, October 2021 [Talk]

  • Electronic Enzyme-Linked Immunosorbent Assay for Detection of COVID-19 Biomarkers

    N. Rafat, H. Zhang, S. P. Peddireddy, A. Sarkar, American Chemical Society Fall Meeting (ACS Fall 2021), Atlanta, USA, August 2021. [Talk]

2020

  • A Feedback-Controlled High-Efficiency Single-Cell Electroporation Chip for Gene and Cell Therapy

    M. Hoyle, A. Sarkar, 2020 Annual Meeting of the Biomedical Engineering Society (BMES2020). Virtual, 2020. [Poster]

Pre-Georgia Tech