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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2024)

This dissertation represents a broad exploration of polymer chemistry, anchored in the principles of the Circular Economy and sustainability. The work presented herein places a strong emphasis on utilizing monomers and polymers sourced from nature. We endeavor to enhance the utility of lignin-derived polymers for commercial applications by improving solubility and thermal properties, while also delving into the synthesis of aromatic-aliphatic polyesters from renewable resources. Lignin-derived poly(ether-amide)s are targeted initially, with the aim of overcoming their solubility limitations through thiol-ene reactions. By introducing small thiol-tagged molecules, the repeating double bonds are reduced, leading to increased chain flexibility and in turn, improved solubility and glass transition temperatures. We then explored the copolymerization of lignin-derived components with lactones for the synthesis of aromatic-aliphatic polyesters. Lactones, such as lactide and glycolide, are natural building blocks pervasive across nature. They were used in ring-opening polymerizations to produce aliphatic alcohol likers. The lactone linkers underwent condensation polymerizations with hydroxycinnamate dimers, creating sustainable, high molecular weight polyesters with desirable thermal properties. These approaches not only enhance the viability of polymers from biomass but also align with the ethos of sustainability by repurposing natural materials.

We then pivot to focus on the development of hydrogel wound dressings, as a biomimetic extracellular matrix. Bioinspired polymers were used to initiate redox hydrogel crosslinking, leading to hydrogels with improved biocompatibility compared to the gold standard approach (APS and TEMED). Finally, this was expanded to the development of in situ forming hydrogel wound dressings that sequester and release antibiotics, analgesics, and hemostatic agents. These hydrogels exhibited rapid formation, controlled release of therapeutic agents, and biocompatibility, addressing the acute need for hemostasis and infection prevention in traumatic blast wounds. In vivo studies demonstrated the safety and efficacy of these hydrogel wound dressings in reducing bacterial burden and promoting wound healing. Overall, this work presents a holistic approach to polymer science, drawing inspiration from nature and rooted in sustainability. By harnessing the potential of natural monomers and polymers, we seek to advance the field while addressing pressing challenges in materials science and healthcare.

    Cover page: Leveraging bioinspired resources for synthesis of sustainable polymeric systems
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2021)
    Upstream exposure of platelets to activating proteins primes platelets for increased downstream adhesion, though the mechanics of platelet translocation before permanently arresting are not well understood. To investigate platelet translocation on platelet-binding proteins, primed platelets transient contacts with immobilized proteins were recorded and analyzed. Using a microfluidic channel, representative of a vascular graft, platelet-activating proteins were covalently attached to the upstream priming, center, and downstream capture positions. Image sequences of platelet interactions with the center protein were captured as platelet-rich plasma (PRP) was perfused through the channel. There was an increase in both platelet pause events and net platelet adhesion on von Willebrand factor, collagen, or fibrinogen following upstream exposure to the same protein. Upstream priming also caused a decrease in average platelet velocity. The duration of transient platelet arrests on the protein-coated surface and the distance that platelets travel between pause events depended on the protein with which they were interacting. The most significant increase in platelet pause events frequency and decrease in average velocity occurred on immobilized von Willebrand factor, compared to the control with no upstream priming. These results demonstrate that platelet priming increases downstream platelet-protein interactions prior to permanent adhesion.
      Cover page: Effect of upstream priming on transient downstream platelet-substrate interactions.
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2020)
      Early disease detection through point-of-care (POC) testing is vital for quickly treating patients and preventing the spread of harmful pathogens. Disease diagnosis is generally accomplished using quantitative polymerase chain reaction (qPCR) to amplify nucleic acids in patient samples, permitting detection even at low target concentrations. However, qPCR requires expensive equipment, trained personnel, and significant time. These resources are not available in POC settings, driving researchers to instead utilize isothermal amplification, conducted at a single temperature, as an alternative. Common isothermal amplification methods include loop-mediated isothermal amplification, recombinase polymerase amplification, rolling circle amplification, nucleic acid sequence-based amplification, and helicase-dependent amplification. There has been a growing interest in combining such amplification methods with POC detection methods to enable the development of diagnostic tests that are well suited for resource-limited settings as well as developed countries performing mass screenings. Exciting developments have been made in the integration of these two research areas due to the significant impact that such approaches can have on healthcare. This review will primarily focus on advances made by North American research groups between 2015 and June 2020, and will emphasize integrated approaches that reduce user steps, reliance on expensive equipment, and the system's time-to-result.
        Cover page: Developments in integrating nucleic acid isothermal amplification and detection systems for point-of-care diagnostics.
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