A microfluidic-SERSplatform for isolation and immuno-phenotyping of antigen specific T-cells

T-cells play a major role in host defense mechanisms against many diseases. With the current growth of immunotherapy approaches, there is a strong need for advanced technologies to detect and characterize these immune cells. Herein, we present a simple approach for the isolation of antigen specific T-cells from the complex biological sample based on T-cell receptor (TCR) and peptide major histocompatibility complex (pMHC) interaction. Subsequently, we characterize those antigen specific T-cells by profiling TCR expression heterogeneity. Our approach utilizes an alternating current electrohydrodynamic (ac-EHD) based microfluidic platform for isolation and surface enhanced Raman scattering (SERS) for TCR expression profiling. The use of ac-EHD enables specific isolation of T-cells by generating a nanoscopic shear force at the double layer of the sensing surface which enhances the frequency of pMHC and TCR interactions and consequently shears off the nonspecific targets. TCR expression profiling of the isolated T-cells was performed by encoding them with SERS-labelled pMHCs followed by SERS detection in bulk as well as in single T-Cell. In proof-of-concept experiments, 56.93 ± 7.31% of the total CD4+T-cells were captured from an excess amount of nonspecific cells (e.g., PBMCs) with high specificity and sensitivity (0.005%). Moreover, TCR analysis data using SERS shows the heterogeneity in the T-cell receptor expression which can inform on the activation status of T-cells and the patient's response to immunotherapy. We believe that this approach may hold potential for numerous applications towards monitoring immune status, understanding therapeutic responses,and effective vaccine development.