ImmunoFET feasibility in physiological salt environments.

Field-effect transistors (FETs) are solid-state electrical devices featuring current sources, current drains and semiconductor channels through which charge carriers migrate. FETs can be inexpensive, detect analyte without label, exhibit exponential responses to surface potential changes mediated by analyte binding, require limited sample preparation and operate in real time. ImmunoFETs for protein sensing deploy bioaffinity elements on their channels (antibodies), analyte binding to which modulates immunoFET electrical properties. Historically, immunoFETs were assessed infeasible owing to ion shielding in physiological environments. We demonstrate reliable immunoFET sensing of chemokines by relatively ion-impermeable III-nitride immunoHFETs (heterojunction FETs) in physiological buffers. Data show that the specificity of detection follows the specificity of the antibodies used as receptors, allowing us to discriminate between individual highly related protein species (human and murine CXCL9) as well as mixed samples of analytes (native and biotinylated CXCL9). These capabilities demonstrate that immunoHFETs can be feasible, contrary to classical FET-sensing assessment. FET protein sensors may lead to point-of-care diagnostics that are faster and cheaper than immunoassay in clinical, biotechnological and environmental applications.

On-demand controlled release of anti-inflammatory and analgesic drugs from conducting polymer films to aid in wound healing.

An electronically-controlled drug delivery system (eDDS) for the on-demand release of anti-inflammatory, anti-microbial and analgesic agents to aid in wound healing is currently under development. The loading of several drugs into conductive polymer films and their subsequent on-demand, controlled release upon application of an electrical potential to the polymer film has been demonstrated. The loading and release (active and passive) of Ibuprofen sodium salt - a negatively charged analgesic and anti-inflammatory agent - from polypyrrole films is described. Major challenges identified include precise control over drug loading and passive release from the conducting polymers in the absence of an applied potential.