Microfluidic Platform for the Enzymatic Pretreatment of Human Serum for the Detection of the Tuberculosis Biomarker Mannose-Capped Lipoarabinomannan

Abstract

Tuberculosis (TB) represents a major public health threat, with millions of new cases reported worldwide each year. A major hurdle to curtailing the spread of this disease is the need for low-cost point-of-care (PoC) diagnostics. Mannose-capped lipoarabinomannan, a significant component of the Mycobacterium tuberculosis bacillus, has been studied as a biomarker for TB, but with little success due to its complexation with endogenous components of body fluids in a manner that interferes with its detection by ELISA and other immunoassays. Recent work by our group and others has shown that complexation can be disrupted with protein-denaturing protocols, and we recently reported on an enzymatic digestion (Proteinase K) sample pretreatment that enables quantitative recovery of spiked ManLAM from human serum. Herein, we report on the transfer of our benchtop sample pretreatment methodology to an automated microfluidic platform. We show that this platform can be configured to carry out the pretreatment process with very little user interaction and yields ManLAM recoveries that are statistically indistinguishable from those achieved by the benchtop process. Plans to integrate this device with a portable sample reader (in development) as a potential approach to an all-in-one PoC TB diagnostic system are briefly discussed.