These stimuli-responsive polymer reagents and fluidic systems evolved into a binary reagent system which enables rapid and efficient bioprocessing by combining two reagents, such as an antibody and a magnetic nanoparticle, that are both modified with a temperature-responsive polymer[1-4]. The key innovation lies in separating the recognition moiety (antibody) from the separation moiety (magnetic particle) during the binding step to improve diffusion and binding, then recombining them via a small temperature change that triggers a polymer phase-change and aggregate formation for bioseparations and diagnostics. This binary reagent system promotes rapid analyte binding with better binding kinetics than with standard magnetic beads[3] because the polymer-antibody conjugates are similar in size to antibodies and <1/100th the size of the microbeads and therefore diffuse rapidly in solution. By separating the antibody and magnetic nanoparticle reagents, the antibody concentration can be increased without increasing the amount of magnetic nanoparticles, thereby enhancing analyte binding without increasing nonspecific binding, resulting in an increased signal-to-noise ratio[2]. The binary reagent system is scalable to higher sample volumes for biomarker enrichment, and enables direct biomarker detection[1]. The binary reagent system has been used in infectious disease diagnostics[4] and cancer profiling by extracting viruses and biomarkers from clinical specimens such as plasma and urine.
Jauregui R, Srinivasan S, Vojtech LN, Gammill HS, Chiu DT, Hladik F, Stayton PS, Lai JJ. Temperature-Responsive Magnetic Nanoparticles for Enabling Affinity Separation of Extracellular Vesicles. ACS Appl Mater Interfaces. 2018;10(40):33847-56.
Phan JC, Nehilla BJ, Srinivasan S, Coombs RW, Woodrow KA, Lai JJ. Human Immunodeficiency Virus (HIV) Separation and Enrichment via the Combination of Antiviral Lectin Recognition and a Thermoresponsive Reagent System. Pharm Res. 2016:1-10.
Nehilla BJ, Hill JJ, Srinivasan S, Chen Y-C, Schulte TH, Stayton PS, Lai JJ. A Stimuli-Responsive, Binary Reagent System for Rapid Isolation of Protein Biomarkers. Analytical Chemistry. 2016.
Lai JJ, Stayton PS. Improving Lateral-Flow Immunoassay (LFIA) Diagnostics via Biomarker Enrichment for mHealth. Mobile Health Technologies: Methods and Protocols. 2015:71-84.