Single-cell analysis offers powerful capabilities of identification of rare sub-populations of cells, understanding heterogeneity of cancerous tumors, and tracking cell differentiation and reprogramming. Despite great potentials for uncovering new biological systems and targeting diseases with precision medicine, single-cell approaches are composed of complex device processes that can cause bias in measurement. In deep sequencing, technical variation in single cell expression data occurs during capture and pre-amplification steps. Similarly, in single-cell protein assays, technical variability can obscure functionally relevant variance.
To better control protein measurement quality in single-cell assays, researchers at the University of California, Berkeley developed a novel method to loading and release protein standard. This method utilizes the surface of modified and functionalized microparticles as vehicles to capture target proteins with desired concentrations. Chelation-assisted click chemistry is applied to demonstrate that protein standards with different molecular masses can be loaded and bounded in a single-cell protein assay. Microparticles are introduced into single-cell devices by either passive gravity, magnetic attraction, or other physicochemical forces. These protein standards from microparticles provide a reference to measure protein mass sizes from individual cells and a quality control for any biases in device fabrication, cell lysis, protein solubility, protein capture, and protein readouts (i.e. antibody probing).