Changxin Lyla Dong

All Publications

• Viral Vector Eluting Lenses for Single-Step Targeted Expression of Genetically-Encoded Activity Sensors for in Vivo Microendoscopic Calcium Imaging. Macromolecular bioscience Jons, C. K., Cheng, D., Dong, C., Meany, E. L., Nassi, J. J., Appel, E. A. 2024: e2400359

  Abstract

  Optical methods for studying the brain offer powerful approaches for understanding how neural activity underlies complex behavior. These methods typically rely on genetically encoded sensors and actuators to monitor and control neural activity. For microendoscopic calcium imaging, injection of a virus followed by implantation of a lens probe is required to express a calcium sensor and enable optical access to the target brain region. This two-step process poses several challenges, chief among them being the risks associated with mistargeting and/or misalignment between virus expression zone, lens probe and target brain region. Here, an adeno-associated virus (AAV)-eluting polymer coating is engineered for gradient refractive index (GRIN) lenses enabling the expression of a genetically encoded calcium indicator (GCaMP) directly within the brain region of interest upon implantation of the lens. This approach requires only one surgical step and guarantees alignment between GCaMP expression and lens in the brain. Additionally, the slow virus release from these coatings increases the working time for surgical implantation, expanding the brain regions and species amenable to this approach. These enhanced capabilities should accelerate neuroscience research utilizing optical methods and advance the understanding of the neural circuit mechanisms underlying brain function and behavior in health and disease.

  View details for DOI 10.1002/mabi.202400359

  View details for PubMedID 39283817

• Water-Enhancing Gels Exhibiting Heat-Activated Formation of Silica Aerogels for Protection of Critical Infrastructure During Catastrophic Wildfire. Advanced materials (Deerfield Beach, Fla.) Dong, C., d'Aquino, A. I., Sen, S., Hall, I. A., Yu, A. C., Crane, G. B., Acosta, J. D., Appel, E. A. 2024: e2407375

  Abstract

  A promising strategy to address the pressing challenges with wildfire, particularly in the wildland-urban interface (WUI), involves developing new approaches for preventing and controlling wildfire within wildlands. Among sprayable fire-retardant materials, water-enhancing gels have emerged as exceptionally effective for protecting civil infrastructure. They possess favorable wetting and viscoelastic properties that reduce the likelihood of ignition, maintaining strong adherence to a wide array of surfaces after application. Although current water-enhancing hydrogels effectively maintain surface wetness by creating a barricade, they rapidly desiccate and lose efficacy under high heat and wind typical of wildfire conditions. To address this limitation, unique biomimetic hydrogel materials from sustainable cellulosic polymers crosslinked by colloidal silica particles are developed that exhibit ideal viscoelastic properties and facile manufacturing. Under heat activation, the hydrogel transitions into a highly porous and thermally insulative silica aerogel coating in situ, providing a robust protective layer against ignition of substrates, even when the hydrogel fire suppressant becomes completely desiccated. By confirming the mechanical properties, substrate adherence, and enhanced substrate protection against fire, these heat-activatable biomimetic hydrogels emerge as promising candidates for next-generation water-enhancing fire suppressants. These advancements have the potential to dramatically improve the ability to protect homes and critical infrastructure during wildfire.

  View details for DOI 10.1002/adma.202407375

  View details for PubMedID 39169738

• Biomimetic Non-ergodic Aging by Dynamic-to-covalent Transitions in Physical Hydrogels. ACS applied materials & interfaces Sen, S., Dong, C., D'Aquino, A. I., Yu, A. C., Appel, E. A. 2024

  Abstract

  Hydrogels are soft materials engineered to suit a multitude of applications that exploit their tunable mechanochemical properties. Dynamic hydrogels employing noncovalent, physically cross-linked networks dominated by either enthalpic or entropic interactions enable unique rheological and stimuli-responsive characteristics. In contrast to enthalpy-driven interactions that soften with increasing temperature, entropic interactions result in largely temperature-independent mechanical properties. By engineering interfacial polymer-particle interactions, we can induce a dynamic-to-covalent transition in entropic hydrogels that leads to biomimetic non-ergodic aging in the microstructure without altering the network mesh size. This transition is tuned by varying temperature and formulation conditions such as pH, which allows for multivalent tunability in properties. These hydrogels can thus be designed to exhibit either temperature-independent metastable dynamic cross-linking or time-dependent stiffening based on formulation and storage conditions, all while maintaining structural features critical for controlling mass transport, akin to many biological tissues. Such robust materials with versatile and adaptable properties can be utilized in applications such as wildfire suppression, surgical adhesives, and depot-forming injectable drug delivery systems.

  View details for DOI 10.1021/acsami.4c03303

  View details for PubMedID 38862125

• Continuous carbon capture in an electrochemical solid-electrolyte reactor. Nature Zhu, P., Wu, Z. Y., Elgazzar, A., Dong, C., Wi, T. U., Chen, F. Y., Xia, Y., Feng, Y., Shakouri, M., Kim, J. Y., Fang, Z., Hatton, T. A., Wang, H. 2023; 618 (7967): 959-966

  Abstract

  Electrochemical carbon-capture technologies, with renewable electricity as the energy input, are promising for carbon management but still suffer from low capture rates, oxygen sensitivity or system complexity1-6. Here we demonstrate a continuous electrochemical carbon-capture design by coupling oxygen/water (O2/H2O) redox couple with a modular solid-electrolyte reactor7. By performing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) redox electrolysis, our device can efficiently absorb dilute carbon dioxide (CO2) molecules at the high-alkaline cathode-membrane interface to form carbonate ions, followed by a neutralization process through the proton flux from the anode to continuously output a high-purity (>99%) CO2 stream from the middle solid-electrolyte layer. No chemical inputs were needed nor side products generated during the whole carbon absorption/release process. High carbon-capture rates (440 mA cm-2, 0.137 mmolCO2 min-1 cm-2 or 86.7 kgCO2 day-1 m-2), high Faradaic efficiencies (>90% based on carbonate), high carbon-removal efficiency (>98%) in simulated flue gas and low energy consumption (starting from about 150 kJ per molCO2) were demonstrated in our carbon-capture solid-electrolyte reactor, suggesting promising practical applications.

  View details for DOI 10.1038/s41586-023-06060-1

  View details for PubMedID 37380692

  View details for PubMedCentralID 7474062

• Fluorinated Multi-Walled Carbon Nanotubes Coated Separator Mitigates Polysulfide Shuttle in Lithium-Sulfur Batteries. Materials (Basel, Switzerland) Salpekar, D., Dong, C., Oliveira, E. F., Khabashesku, V. N., Gao, G., Ojha, V., Vajtai, R., Galvao, D. S., Babu, G., Ajayan, P. M. 2023; 16 (5)

  Abstract

  Li-S batteries still suffer from two of the major challenges: polysulfide shuttle and low inherent conductivity of sulfur. Here, we report a facile way to develop a bifunctional separator coated with fluorinated multiwalled carbon nanotubes. Mild fluorination does not affect the inherent graphitic structure of carbon nanotubes as shown by transmission electron microscopy. Fluorinated carbon nanotubes show an improved capacity retention by trapping/repelling lithium polysulfides at the cathode, while simultaneously acting as the "second current collector". Moreover, reduced charge-transfer resistance and enhanced electrochemical performance at the cathode-separator interface result in a high gravimetric capacity of around 670 mAh g-1 at 4C. Unique chemical interactions between fluorine and carbon at the separator and the polysulfides, studied using DFT calculations, establish a new direction of utilizing highly electronegative fluorine moieties and absorption-based porous carbons for mitigation of polysulfide shuttle in Li-S batteries.

  View details for DOI 10.3390/ma16051804

  View details for PubMedID 36902922

  View details for PubMedCentralID PMC10004040