Microfluidic Capture and Quantification of HIV

Once a patient is diagnosed as HIV-positive, tests of viral load (the concentration of virus circulating in the blood) are performed routinely in order to monitor disease progression and ensure treatment effectiveness. Currently, there is no procedure to measure viral load in a point-of-care setting. It often takes upwards of two weeks to receive a patient’s viral load results from central facilities, making it difficult for doctors to make treatment decisions or adjust medication in the case of drug resistance. Microfluidic technology offers the ability to analyze small sample volumes, encouraging the development of point-of-care systems for viral diagnostics. A microfluidic viral load analyzer needs to separate the HIV virions from plasma and quantify the targets. The small size of virions limits the use of traditional, flat-bed, immunoaffinity microfluidic devices. Thus, here we validate the effectiveness of a nanoporous filtration matrix to isolate pseudo HIV virions from a solution [1]. Adapting the methods of da la Escosura and Muniz, virions are tagged with gold nanoparticles, and the virion-gold complexes are augmented with silver deposition, increasing the volume that the complexes occupy within the capture membrane [2]. These aggregates block flow of an ionic solution through the membrane pores. The reduction of ion flow as viral capture increases can be quantified through cyclic voltammetric analysis. Initial experiments show a correlation between a decrease in peak current and an increase in simulated viral load (n=4, R2=0.934). This system, once optimized, has the potential to perform viral load quantification in a point-of-care setting. 1. Surawathanawises, Krissada. “Polymeric Nanoporous Structures Integrated into Microfluidic Device for HIV Detection,” PhD Dissertation, Lehigh University, Bethlehem, PA, 2014. 2. de la Escosura-Muniz, A.; Merkoci, A. “A Nanochannel/Nanoparticle-Based Filtering and Sensing Platform for Direct Detection of a Cancer Biomarker in Blood,” Small, 2011.https://preserve.lehigh.edu/undergrad-scholarship-freed-posters/1007/thumbnail.jp