Dropblot Design Integrates Droplet Microfluidics With Single-Cell Electrophoresis

Patent Status

Patent Pending

Brief Description

Single-cell analyses are revolutionizing biomedicine and biology, with genomics (DNA) and transcriptomics (RNA) tools leading the way. At the protein-level, single-cell analyses are limited to mass spectrometry and immunoassays. Neither assay provides comprehensive coverage of proteome for single cells, missing key protein forms (called isoforms). 

UC Berkeley researchers have developed a hybrid droplet-electrophoresis device, termed “DropBlot”, to detect proteins from patient-derived tissue biospecimens relevant to clinical medicine and pathology. The DropBlot takes advantage of water-in-oil (W/O) droplets to encapsulate single cells derived from chemically fixed tissues, thus providing a picoliter-volume reaction chamber in which said cells are lysed and subjected to harsh lysis conditions (100ºC, 2 hours), as needed for fixed cells. We report an all-in-one microdevice to facilitate cell-laden droplet loading with >98% microwell occupancy. Droplets remain intact under the electric field and protein isoforms are shown to electromigrate out of the droplet and into a microfluidic separation channel where protein sizing takes place via the action of electrophoresis in a photoactive polyacrylamide (PA) gel. DropBlot has been successfully applied to live and fixed cancer cell lines and resolved proteins with high sensitivity.

Suggested uses

• single-cell protein analysis device
• protein isoform detection