Abstract

A New Lab-on-a-Chip (LOC) Platform with On-Chip Reservoirs of Liquid Reagents for POCT Applications

Chong Ahn, Professor, University of Cincinnati

A new lab-on-a-chip (LOC) platform with on-chip liquid reservoirs holding all reagents for high-sensitive immunoassay has been designed, developed and characterized for Tumor Necrosis Factor - alpha (TNF-alpha), a protein biomarker that is caused by lung inflammations or cancers. The designed LOC device is composed of four reservoirs for sample, enzyme conjugated detection antibody, wash buffer and chemiluminescence substrate in liquid form, along with spiral reacting microchannels coated with capture antibody. All reservoirs and spiral microchannels were connected in series and designed to perform sequential delivery of immunoassay reagents with minimal user intervention.  The developed LOC measured TNF-a concentration as low as 16 pg/mL in plasma sample from rats and also had a limit of detection (LOD) of 0.5 pg/mL in spiked artificial plasma. The detected range of TNF-a is low enough to diagnose early responses to lung inflammation or cancers in humans. In addition, the analysis time was drastically reduced, to about 30 minutes as opposed to hours in conventional assay methods. Successful implementation of a high-sensitive, chemiluminescence based immunoassay on a pre-loaded LOC, as reported in this work, can pave the way towards developing a new POCT testing platform.