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  1. Free, publicly-accessible full text available January 23, 2025
  2. Abstract

    A key challenge in bioelectronics is to establish and improve the interface between electronic devices and living tissues, enabling a direct assessment of biological systems. Sensors integrated with plant tissue can provide valuable information about the plant itself as well as the surrounding environment, including air and soil quality. An obstacle in developing interfaces to plant tissue is mitigating the formation of fibrotic tissues, which can hinder continuous and accurate sensor operation over extended timeframes. Electronic systems that utilize suitable biocompatible materials alongside appropriate fabrication techniques to establish plant-electronic interfaces could provide for enhanced environmental understanding and ecosystem management capabilities. To meet these demands, this study introduces an approach for integrating printed electronic materials with biocompatible cryogels, resulting in stable implantable hydrogel-based bioelectronic devices capable of long-term operation within plant tissue. These inkjet-printed cryogels can be customized to provide various electronic functionalities, including electrodes and organic electrochemical transistors (OECTs), that exhibit high electrical conductivity for embedded conducting polymer traces (up to 350 S/cm), transconductance for OECTs in the mS range, a capacitance of up to 4.2 mF g−1in suitable structures, high stretchability (up to 330% strain), and self-healing properties. The biocompatible functionalized cryogel-based electrodes and transistors were successfully implanted in plant tissue, and ionic activity in tomato plant stems was collected for over two months with minimal scar tissue formation, making these cryogel-based printed electronic devices excellent candidates for continuous, in-situ monitoring of plant and environmental status and health.

     
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    Free, publicly-accessible full text available December 1, 2024
  3. We numerically compare the null quality for STED microscopy generated by Laguerre-Gaussian beams with orbital angular momentum and donut beams generated by incoherent addition of orthogonal Hermite Gaussian beams when imaging deep biological tissue.

     
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  4. Abstract

    Applications of 3D printing that range from temporary medical devices to environmentally responsible manufacturing will benefit from printable resins that yield polymers with controllable architecture, material properties, and degradation behavior. Towards this goal, poly(β‐amino ester) (PBAE)‐diacrylate resins are investigated due to the wide range of available chemistries and tunable material properties. PBAE‐diacrylate resins are synthesized from hydrophilic and hydrophobic chemistries and with varying electron densities on the ester bond to provide control over degradation. Hydrophilic PBAE‐diacrylates led to degradation behaviors characteristic of bulk degradation, while hydrophobic PBAE‐diacrylates led to degradation behaviors dominated initially by surface degradation and then transitioned to bulk degradation. Depending on the chemistry, the crosslinked PBAE‐polymers exhibited a range of degradation times under accelerated conditions, from complete mass loss in 90 min to minimal mass loss at 45 days. Patterned features with 55 µm resolution are achieved across all resins, but their fidelity is dependent on PBAE‐diacrylate molecular weight, reactivity, and printing parameters. In summary, simple chemical modifications in the PBAE‐diacrylate resins coupled with projection microstereolithography enable high‐resolution 3D printed parts with similar architectures and initial properties but widely different degradation rates and behaviors.

     
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