A multiplexed immuno-sensor for on-line and automated monitoring of tissue culture protein biomarkers.

Frequent on-line and automated monitoring of multiple protein biomarkers level secreted in the culture media during tissue growth is essential for the successful development of Tissue Engineering and Regenerative Medicine (TERM) products. Here, we present a low-cost, rapid, reliable, and integrable anion-exchange membrane-(AEM) based multiplexed sensing platform for this application. Unlike the gold-standard manual ELISA test, incubation/wash steps are optimized for each target and precisely metered in microfluidic chips to enhance selectivity.

Universal Features of Non-equilibrium Ionic Currents through Perm-Selective Membranes: Gating by Charged Nanoparticles/Macromolecules for Robust Biosensing Applications.

The presence of a small number (∼1000) of charged nanoparticles or macromolecules on the surface of an oppositely charged perm-selective membrane is shown to sensitively gate the ionic current through the membrane at a particular voltage, thus producing a voltage signal much larger than thermal noise. We show that, at sufficiently high voltages, surface vortices appear on the membrane surface and sustain an ion-depleted boundary layer that controls the diffusion length and ion current. An asymmetric vortex bifurcation occurs beyond a critical voltage to reduce the diffusion length and the differential resistance by half.

Extracellular vesicle microRNA quantification from plasma using an integrated microfluidic device.

Extracellular vesicles (EV) containing microRNAs (miRNAs) have tremendous potential as biomarkers for the early detection of disease. Here, we present a simple and rapid PCR-free integrated microfluidics platform capable of absolute quantification (<10% uncertainty) of both free-floating miRNAs and EV-miRNAs in plasma with 1 pM detection sensitivity. The assay time is only 30 minutes as opposed to 13 h and requires only ~20 μL of sample as oppose to 1 mL for conventional RT-qPCR techniques.

Simultaneous isolation and preconcentration of exosomes by ion concentration polarization.

Exosomes carry microRNA biomarkers, occur in higher abundance in cancerous patients than in healthy ones, and because they are present in most biofluids, including blood and urine, these can be obtained noninvasively. Standard laboratory techniques to isolate exosomes are expensive, time consuming, provide poor purity, and recover on the order of 25% of the available exosomes. We present a new microfluidic technique to simultaneously isolate exosomes and preconcentrate them by electrophoresis using a high transverse local electric field generated by ion-depleting ion-selective membrane.

Surface acoustic wave devices for chemical sensing and microfluidics: A review and perspective.

Surface acoustic waves (SAWs), are electro-mechanical waves that form on the surface of piezoelectric crystals. Because they are easy to construct and operate, SAW devices have proven to be versatile and powerful platforms for either direct chemical sensing or for upstream microfluidic processing and sample preparation. This review summarizes recent advances in the development of SAW devices for chemical sensing and analysis.