Biology subjects

Rivnay, J.

Publications and source records attributed to Rivnay, J..

3 recordsLinked to original sources

bioRxiv2023

A Hybrid Transistor with Transcriptionally Controlled Computation and Plasticity

Organic electrochemical transistors (OECTs) are ideal devices for translating biological signals into electrical readouts and have applications in bioelectronics, biosensing, and neuromorphic computing. Despite their potential, developing programmable and modular methods for living systems to interface with OECTs has proven challenging. Here we describe hybrid OECTs containing the model electroactive bacterium Shewanella oneidensis that enable the transduction of biological computations to electrical responses. Specifically, we fabricated planar p-type OECTs and demonstrated that channel de-doping is driven by extracellular electron transfer (EET) from S. oneidensis. Leveraging this mechanistic understanding and our ability to control EET flux via transcriptional regulation, we used plasmid-based Boolean logic gates to translate biological computation into current changes within the OECT. Finally, we demonstrated EET-driven changes to OECT synaptic plasticity. This work enables fundamental EET studies and OECT- based biosensing and biocomputing systems with genetically controllable and modular design elements.

bioengineering↗

bioRxiv2023

Electrocatalytic on-site oxygenation for transplanted cell-based-therapies

Implantable cell therapies and tissue transplants require sufficient oxygen supply to function and are limited by a delay or lack of vascularization from the transplant host1, 2. Exogenous oxygen production can support cells and tissues, such as pancreatic islets and engineered therapeutic cells. Previous oxygenation strategies have targeted gas circulation or decomposition of solid peroxides. These strategies however require bulky implants, transcutaneous supply lines, and are limited in their total oxygen production or regulation3, 4. Readily integrated and controlled production of oxygen has eluded cell therapy devices. Here, we show an electrocatalytic approach that enables bioelectronic control of oxygen generation in complex cellular environments to sustain engineered cell viability and therapy production under hypoxic stress and at high cell densities. Nanostructured sputtered iridium oxide serves as an ideal catalyst for oxygen evolution reaction (OER) at neutral pH. It enables a lower OER onset and shows selective oxygen production without evolution of toxic side products over a 300 mV window of operation. This electrocatalytic on site oxygenator (ecO2) can sustain high cell loadings (>60k cells/mm3) in hypoxic conditions in vitro and in vivo. Our results demonstrate that exogenous oxygen production devices can be readily integrated into bioelectronic platforms and enable high cell loadings in smaller device footprints with broad applicability.

bioengineering↗

bioRxiv2022

Organic Electrochemical Transistor as an On-site Signal Amplifier for Electrochemical Aptamer-based Sensing

Electrochemical aptamer-based (E-AB) sensors are typically deployed as individual, passive, surface-functionalized electrodes, but they exhibit limited sensitivity especially when the area of the electrode is reduced for miniaturization purposes. We demonstrated that organic electrochemical transistors (OECTs), electrolyte gated tran-istors with volumetric gating, can serve as on-site amplifiers to improve the sensitivity of single electrode-based E-AB sensors. By monolithically integrating an Au working/sensing electrode, on-chip Ag/AgCl reference electrode and Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) counter electrode -- also serving as the OECT channel, we can simultaneously perform OECT testing and traditional electroanalytical measurement on E-AB sensors including cyclic voltammetry (CV) and square-wave voltammetry (SWV). This device can directly amplify the current from the E-AB sensor via the in-plane current modulation in the counter electrode/transistor channel. The integrated OECT-based E-AB sensor is able to sense transforming growth factor beta 1 (TGF-{beta}1) with 3 to 4 orders of magnitude enhancement of sensitivity compared to that in a single electrode-based E-AB sensor (292 {micro}A/dec vs. 85 nA/dec for OECT vs. single electrode SWV). This approach is believed to be universal, which can be applied to a wide range of tethered electrochemical reporter-based sensors to enhance sensitivity, aiding in sensor miniaturization and easing the burden on backend signal processing.

bioengineering↗