About

Jonathan Rivnay is the Jerome B. Cohen Professor in Engineering and a faculty member in Biomedical Engineering and Materials Science and Engineering at Northwestern University. He serves as the Director of PhD Admissions in Biomedical Engineering. Rivnay's research group engineers organic and biohybrid bioelectronic materials, devices, and systems designed to interface with biological systems and traditional optoelectronics. His work involves understanding the active properties of organic materials, including mixed ionic-electronic conduction and actuation, and utilizing these properties for sensing and stimulation in biomedical applications. Recent efforts in his lab include developing biohybrid devices that combine synthetic biology with bioelectronics to extend capabilities in sensing and actuation/therapy. His research spans from fundamental materials and interface studies to the development of devices and systems aimed at diagnostics, therapeutics, rehabilitation, and tissue regeneration.

Research topics

• Computer Science
• Materials science
• Nanotechnology
• Optoelectronics
• Engineering
• Electrical engineering
• Artificial Intelligence
• Physics
• Biology
• Combinatorial chemistry
• Manufacturing engineering
• Cell biology
• Chemistry
• Biomedical engineering
• Systems engineering
• Business
• Medicine

Selected publications

• Coupled Ionic–Electronic Transport in Vertical OECTs: A Combined Experimental and Simulation Study

  Advanced Electronic Materials · 2026-04-01

  articleOpen access

  ABSTRACT Organic electrochemical transistors (OECTs) uniquely couple ionic and electronic transport, enabling high transconductance and low‐voltage operation for bioelectronic applications. While the Bernards–Malliaras model successfully describes lateral OECTs, it fails to capture the coupled space‐ and time‐dependent processes that govern vertical OECTs (vOECTs), particularly for disordered semiconductors and high ion concentrations. Here, we present a 2D numerical simulation that self‐consistently couples ion transport and electronic charge dynamics, validated against experimental data from n‐type poly(benzimidazobenzophenanthroline) (BBL) vOECTs. The simulations reproduce steady‐state and transient characteristics, revealing key physical mechanisms including diffusion‐dominated electronic transport, contact tunneling, energy loss at the semiconductor/electrolyte interface, and gate‐induced ion acceleration via band bending. The simulation also quantifies geometry‐dependent mobility discrepancies and anisotropic ionic transport between vertical and lateral architectures, consistent with recent reports on mixed ionic–electronic conductors. By bridging microscopic mechanisms with experimental observables, this work provides a predictive framework for vOECT operation and offers design guidelines for high‐performance, high‐density bioelectronic systems.

  PublisherDOI

• Robust Interpretation of Electrochemical Impedance Spectra Using Numerical Complex Analysis

  ACS Measurement Science Au · 2026-01-23

  articleOpen access

  Electrochemical Impedance Spectroscopy (EIS) is a noninvasive technique widely used for understanding charge transfer and charge transport processes in electrochemical systems and devices. Standard approaches for the interpretation of EIS data involve starting with a hypothetical circuit model for the physical processes in the device based on experience/intuition and then fitting the EIS data to this circuit model. This work explores a mathematical approach for extracting key characteristic features from EIS data by relying on fundamental principles of complex analysis. These characteristic features can suggest the presence of inductors and constant phase elements (nonideal capacitors) from impedance data and enable us to answer questions about the identifiability and nonuniqueness of equivalent circuit models. In certain scenarios such as models with only resistors and capacitors, we are able to enumerate all possible families of circuit models. Finally, we apply the mathematical framework presented here to real-world electrochemical systems and highlight results using impedance measurements from a lithium-ion battery coin cell.

  PublisherDOI

• Design of a wireless, fully implantable platform for in-situ oxygenation of encapsulated cell therapies

  Device · 2026-03-27

  article
  PublisherDOI

• Broadly applicable hydrophilic additive enhances electrochemical transistor function

  Proceedings of the National Academy of Sciences · 2026-03-02 · 3 citations

  articleOpen accessCorresponding

  Organic semiconductors offering efficient mixed ionic-electronic charge transport are key components of organic electrochemical transistors (OECTs) needed for future bioelectronics and other technologies. However, hydrophobic semiconductors typically have limited ion mobility and are unstable in aqueous environments, restricting OECT applications. To address these issues, we report a broadly applicable strategy for high-performance OECTs by blending polymeric semiconductors with a photocrosslinkable hydrophilic ion-conducting supplement, poly(ethyleneglycol)-dimethylacrylate (PEGDMA). The result is ordered, interconnected semiconductor domains within an amorphous ion-conducting matrix, enabling rapid and reversible doping/dedoping without compromising charge transport. This approach enhances OECT performance across diverse electrolytes, semiconductors, and device architectures. Furthermore, PEGDMA enables high-resolution photopatterning of both semiconductors (<0.4 μm) and electrolytes (<2 μm), affording high-stability OECTs sustaining >10,000 cycles. This approach also enables wafer-scale array fabrication of 2,548 OECTs on 2" wafer, and miniaturized inverter, NAND, and NOR circuits. Also demonstrated are integration of these OECTs with a photosensor, creating a vision sensing array (10 × 10 pixels) that mimics visual image processing similar to the brain's perception system.

  PublisherDOI

• Biohybrid Robots with Embedded Conductive Fibers for Actuation, Sensing, and Closed-loop Control

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-04-06

  articleOpen accessSenior authorCorresponding

  Living organisms achieve adaptive actuation through the seamless integration of neural motor control circuitry and proprioceptive feedback. While biohybrid robotics aims to replicate these capabilities by merging engineered muscle with synthetic scaffolds, the field remains limited by interfaces that lack the efficiency and closed-loop regulation of natural neuromuscular systems. Here, we introduce a biohybrid muscle actuator system featuring a bioelectronic interface based on soft poly(3,4-ethylenedioxythiophene) (PEDOT) fibers for stimulation and sensing. These fibers conformally couple to muscle tissues, eliciting robust contractions at voltages as low as 1 V-requiring ultra-low power (0.376 ± 0.034 mW) and preserving long-term tissue viability. By leveraging the independent addressability of these fibers, we demonstrate selective actuation of individual muscle units to achieve precise spatiotemporal control of a two-muscle-powered walking biohybrid robot, reaching a locomotion speed of 5.43 ± 0.79 mm/min. When configured as strain sensors, the fibers exhibit a high gauge factor of 155.45 ± 6.59 and resolve contractile displacements within tens of micrometers. We demonstrate that this sensing modality can be integrated into a closed-loop controller to autonomously modulate stimulation based on real-time feedback, significantly mitigating muscle fatigue (p = 0.038) during continuous operation. This work establishes a versatile platform for efficient actuation and intrinsic feedback sensing, providing a blueprint for efficient, autonomous, and adaptive biohybrid machines.

  PublisherOA PDFDOI

• Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors

  Journal of Visualized Experiments · 2025-01-31

  article

  Extracellular electron transfer (EET) is a process through which certain microorganisms can transfer electrons across their cell membranes to external electron acceptors, linking cellular metabolism to their environment. While Geobacter and Shewanella have been the primary models for EET research, emerging studies reveal that EET-active species are also associated with fermentation and the human gut microbiome. Leveraging the ability of EET to bridge biological and electronic systems, we present a protocol for using organic electrochemical transistors (OECTs) to translate microbial EET activity into easily detectable electrical signals. This system enables the use of cellular responses to external stimuli for biosensing and biocomputing applications. Specifically, we demonstrated the de-doping of the p-type poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) channel in the OECT is driven by cellular EET from Shewanella oneidensis. By transcriptionally controlling EET flux by genetic circuits, we establish the biosensing capability of this hybrid OECT system to detect chemical stimuli, such as inducer molecules. Furthermore, we introduce plasmid-based Boolean logic gates within the cells, allowing them to process environmental signals and drive current changes in the OECTs, further demonstrating the biocomputing potential of these devices. This method provides a novel interface between biological systems and electronics, enabling future high-throughput screening, biosensing, and biocomputing applications.

  PublisherDOI

• Disulfide Incorporated Pyridine and Pyridinium Push–Pull Dyes for Optical Sensing and Antifouling Electrodes

  Langmuir · 2025-03-18

  article

  A new push–pull dye has been developed as a pH indicator when covalently copolymerized in a lipoic acid–based polymer (LA-Py). Furthermore, various charged forms of the dyes are investigated as antifouling diluents in self-assembled monolayers (SAMs) on gold electrodes. The dyes contain an amino donor incorporated into a seven-membered heterocyclic disulfide ring, a pyridine or pyridinium acceptor moiety, and an oligo-phenylene ethylene (OPE) conjugated bridge. A common characteristic of a push–pull dye is the high sensitivity to solvent dipoles such as the Stokes shifts of 176 and 211 nm for pyridine (Py) in acetonitrile and pyridinium (MePy) in chloroform, respectively. This is coupled with a decrease in quantum yields with increasing polarity of the solvents. The LA-Py has an apparent pKa of 3.5 and showed high sensitivity in acidic conditions with robust cycling between pH 7 and −0.08, producing an average contrast of 36% over 10 cycles. Incorporated into a SAM, the zwitterionic pyridinium sulfonate (SPy) derivative demonstrated antifouling to BSA by continuous monitoring of impedance with electrochemical impedance spectroscopy and ionic permeability of K3[FeCN6] by cyclic voltammetry. When “backfilled” with mercaptohexadecane (MHD), an enhanced SAM was formed (SPy + MHD), which showed resistance to ion penetration and improved antifouling.

  PublisherDOI

• Sulfonated <scp>PEDOT</scp> ‐Modified Decellularized Arteries as Electroactive Scaffolds for Vascular Tissue Engineering

  Journal of Biomedical Materials Research Part A · 2025-12-01

  articleOpen accessCorresponding

  Electroactive biomaterials present new opportunities for "smart" vascular grafts capable of supporting tissue integration while enabling electrical stimulation, sensing, or real-time modulation of the vascular environment. In this study, a conductive vascular conduit was engineered by incorporating sulfonated poly(3,4-ethylenedioxythiophene) (S'PEDOT) into extracellular matrix (ECM)-based scaffolds. Initial screening in collagen sponges identified S'PEDOT concentrations that supported biocompatibility with primary endothelial and smooth muscle cells while minimizing platelet adhesion. This strategy was then applied to decellularized rat aortas, which were functionalized with S'PEDOT and evaluated for electrical conductivity, tensile mechanics, and structural integrity. The modified grafts retained native architecture and mechanical compliance while exhibiting significantly enhanced conductivity compared to unmodified controls. In vivo biocompatibility was assessed by subcutaneous implantation in rats, followed by histological and immunohistochemical analyses. The S'PEDOT-modified grafts elicited minimal inflammatory response and preserved tissue architecture. These findings demonstrate a promising approach for integrating conductive polymers into natural scaffolds to develop electroactive vascular grafts, supporting future applications in multifunctional and responsive vascular devices.

  PublisherOA PDFDOI

• Programming Aptamer–Protein Complexation Kinetics via Modulation of G-Quadruplex Secondary Structure

  Journal of the American Chemical Society · 2025-09-15 · 3 citations

  article

  Aptamers have emerged as key receptors in the pursuit of universal biomolecular monitoring. However, while many aptamers possess excellent association rates, they tend to exhibit slow dissociation kinetics. While these slow off-rates are great for single-use applications, they pose a significant challenge for applications requiring continuous, repeated measurements where hysteresis complicates subsequent binding events. The G-quadruplex represents a common motif in many high-specificity aptamers and is composed of complexed guanine residues. Here, we present a method for modulating G-quadruplex aptamer binding kinetics through use of a polycytosine strand that can destabilize quadruplex structure and accelerate target release in a predictable manner. We demonstrate this phenomenon for several aptamer targets, including thrombin, interferon-gamma, and nucleolin, and highlight the ability of these modified aptamers to capture dynamic changes in analyte concentration on minute time scales.

  PublisherDOI

• Robust interpretation of electrochemical impedance spectra using numerical complex analysis

  PubMed · 2025-10-03

  preprintOpen access

  Electrochemical Impedance Spectroscopy (EIS) is a noninvasive technique widely used for understanding charge transfer and charge transport processes in electrochemical systems and devices. Standard approaches for the interpretation of EIS data involve starting with a hypothetical circuit model for the physical processes in the device based on experience/intuition and then fitting the EIS data to this circuit model. This work explores a mathematical approach for extracting key characteristic features from EIS data by relying on fundamental principles of complex analysis. These characteristic features can suggest the presence of inductors and constant phase elements (nonideal capacitors) from impedance data and enable us to answer questions about the identifiability and nonuniqueness of equivalent circuit models. In certain scenarios such as models with only resistors and capacitors, we are able to enumerate all possible families of circuit models. Finally, we apply the mathematical framework presented here to real-world electrochemical systems and highlight results using impedance measurements from a lithium-ion battery coin cell.

  PublisherOA PDFDOI

Recent grants

• ASCENT: BioNet: A distributed network of bioelectronic devices for closed-loop control of physiological processes

  NSF · $1.3M · 2020–2024

• CAREER: Understanding the Role of Structure on Ionic/Electronic Properties in Polymeric Mixed Conductors

  NSF · $552k · 2018–2024

Frequent coauthors

• Iain McCulloch

  University of Oxford

  96 shared

• Alberto Salleo

  59 shared

• George G. Malliaras

  University of Cambridge

  58 shared

• Bryan D. Paulsen

  Northwestern University

  55 shared

• Ruiheng Wu

  Northwestern University

  46 shared

• Sahika Inal

  King Abdullah University of Science and Technology

  32 shared

• P. Leleux

  UCLouvain

  32 shared

• Michael F. Toney

  31 shared

Labs

• Rivnay GroupPI

Education

• M.Sc., Ph.D., Materials Science and Engineering

  Stanford University

  2011

• B.Sc., Materials Science and Engineering

  Cornell University

  2006

Awards & honors

• Materials Research Society Postdoctoral Award, 2014
• William E. and Diane M. Spicer Young Investigator Award, 201…
• Melvin P. Klein Scientific Development Award, 2011
• Materials Research Society Graduate Student Gold Award, 2011
• Robert A. Huggins Award, 2010