Browsing by Author "Tseng, Chia-Ping"

Now showing 1 - 4 of 4
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    Conductive Polymeric Interfaces for Cell-Material Communication and Signal Amplification in Microbial Bioelectronics
    (2022-04-21) Tseng, Chia-Ping; Verduzco, Rafael
    Bioelectronics is the integration of biology with microelectronic devices. The combination of biology with microelectronics can potentially provide new systems for electricity generation, chemical production, environmental sensing, health diagnosis, disease treatment, a greater understanding of biology, and biomimetic materials and devices. Microelectronic devices are traditionally based on hard materials and rely on electronic signals while biology uses soft materials and a combination of ionic, molecular, and electron transfer for communication and signaling. Therefore, producing functional devices through the integration of these two fields requires addressing fundamental challenges in material properties, forms of signaling and communication, biocompatibility, and structures across various length scales. This thesis focuses on the development of functional electrode surface and polymeric networks and the fabrication of novel microbial bioelectronic devices to enhance bidirectional electrical and molecular communication. To bridge the gap between the biology and electronic worlds and improve the communication between them, this thesis pinpoints the solution for three key challenges including stable microbial adhesion, microbial patterning, and signal amplification. Prior research has developed and engineered two or three-dimensional biology-material interface layers to achieve dense microbial encapsulation, efficient electron transfer, and better nutrient and waste transport. However, we still lack electrode modification approaches that can be deposited easily and cheaply on an electrode surface, are amenable to patterning, and produce a significant enhancement to current densities. This thesis shows a solution-processable conductive polymer thin film that readily modifies the electrodes for diverse bioelectronics that take advantage of the high current density and microbial patterning on a surface. Furthermore, the integration of novel bioelectronic devices, specifically organic electrochemical transistor (OECT), with the microbes and enzymes demonstrates the power of amplifying minuscule electronic and ionic signals from biological entities compared to traditional three-electrode electrochemical systems. This research will lead to robust devices for monitoring enzymatic and microbial activities and benefit the material design and development of microbial bioelectronics for a broad class of sensitive and responsive biosensors.
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    Patterning, Transfer, and Tensile Testing of Covalent Organic Framework Films with Nanoscale Thickness
    (American Chemical Society, 2021) Zhu, Dongyang; Hu, Zhiqi; Rogers, Tanya K.; Barnes, Morgan; Tseng, Chia-Ping; Mei, Hao; Sassi, Lucas M.; Zhang, Zhuqing; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, Rafael
    Covalent organic frameworks (COFs) are promising materials for a variety of applications, including membrane-based separations, thin-film electronics, and as separators for electrochemical devices. Robust mechanical properties are critical to these applications, but there are no reliable methods for patterning COFs or producing free-standing thin films for direct mechanical testing. Mechanical testing of COFs has only been performed on films supported by a rigid substrate. Here, we present a method for patterning, transferring, and measuring the tensile properties of free-floating nanoscale COF films. We synthesized COF powders by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and terephthalaldehyde (PDA) and prepared uniform thin films by spin casting from a mixture of trifluoroacetic acid and water. The COF films were then reactivated to recover crystallinity and patterned by plasma etching through a poly(dimethylsiloxane) (PDMS) mask. The films were transferred to the surface of water, and we performed direct tensile tests. We measured a modulus of approximately 1.4 GPa for TAPB-PDA COF and a fracture strain of 2.5%, which is promising for many applications. This work advances the development of COFs for thin-film applications by demonstrating a simple and generally applicable approach to cast, pattern, and transfer COF thin films and to perform direct mechanical analysis.
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    Solution-Deposited and Patternable Conductive Polymer Thin-Film Electrodes for Microbial Bioelectronics
    (Wiley, 2022) Tseng, Chia-Ping; Liu, Fangxin; Zhang, Xu; Huang, Po-Chun; Campbell, Ian; Li, Yilin; Atkinson, Joshua T.; Terlier, Tanguy; Ajo-Franklin, Caroline M.; Silberg, Jonathan J.; Verduzco, Rafael
    Microbial bioelectronic devices integrate naturally occurring or synthetically engineered electroactive microbes with microelectronics. These devices have a broad range of potential applications, but engineering the biotic–abiotic interface for biocompatibility, adhesion, electron transfer, and maximum surface area remains a challenge. Prior approaches to interface modification lack simple processability, the ability to pattern the materials, and/or a significant enhancement in currents. Here, a novel conductive polymer coating that significantly enhances current densities relative to unmodified electrodes in microbial bioelectronics is reported. The coating is based on a blend of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) crosslinked with poly(2-hydroxyethylacrylate) (PHEA) along with a thin polydopamine (PDA) layer for adhesion to an underlying indium tin oxide (ITO) electrode. When used as an interface layer with the current-producing bacterium Shewanella oneidensis MR-1, this material produces a 178-fold increase in the current density compared to unmodified electrodes, a current gain that is higher than previously reported thin-film 2D coatings and 3D conductive polymer coatings. The chemistry, morphology, and electronic properties of the coatings are characterized and the implementation of these coated electrodes for use in microbial fuel cells, multiplexed bioelectronic devices, and organic electrochemical transistor based microbial sensors are demonstrated. It is envisioned that this simple coating will advance the development of microbial bioelectronic devices.
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    Transformation of One-Dimensional Linear Polymers into Two-Dimensional Covalent Organic Frameworks Through Sequential Reversible and Irreversible Chemistries
    (American Chemical Society, 2021) Zhu, Dongyang; Li, Xiaoyi; Li, Yilin; Barnes, Morgan; Tseng, Chia-Ping; Khalil, Safiya; Rahman, Muhammad M.; Ajayan, Pulickel M.; Verduzco, Rafael
    Covalent organic frameworks (COFs) are crystalline porous materials linked by dynamic covalent bonds. Dynamic chemistries enable the transformation of an initially amorphous network into a porous and crystalline COF. While dynamic chemistries have been leveraged to realize transformations between different types of COFs, including transformations from two-dimensional (2D) to three-dimensional (3D) COFs and insertion of different linking groups, the transformation of linear polymers into COFs has not yet been reported. Herein, we demonstrate an approach to transform linear imine-linked polymers into ketone-linked COFs through a linker replacement strategy with triformylphloroglucinol (TPG). TPG first reacts through dynamic chemistry to replace linkers in the linear polymers and then undergoes irreversible tautomerism to produce ketone linkages. We have analyzed the time-dependent transformation from the linear polymer into COF through powder X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) to understand the transition and substitution mechanisms. This work demonstrates another route to produce COFs through sequential reversible and irreversible chemistries and provides a potential approach to synthesizing COFs through the solution processing of linear polymers followed by transformation into the desired COF structure.