3D-bioprinting of sustained- and phased-release antibiotic and probiotic scaffolds to treat bacterial vaginosis

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PROJECT SUMMARY Bacterial vaginosis (BV) is a dysbiosis of the vaginal microbiome that affects ~29% of reproductive age women and is linked with higher risks of adverse pregnancy outcomes, postsurgical infections, and sexually transmitted infections. While lactobacilli typically dominate the healthy vagina, BV is characterized by low lactobacilli levels and an overgrowth of diverse anaerobic bacteria, most often including Gardnerella and Prevotella. Current oral or topical antibiotic treatments alleviate symptoms in 80% of women, at least temporarily. However, most women will experience a recurrence of BV within one-year post-treatment. A recent clinical study showed that a vaginal probiotic treatment regimen (with Lactobacillus crispatus), used following a vaginal course of antibiotics (metronidazole), significantly improved long-term treatment efficacy. Unfortunately, current topically-applied formulations require repeated administrations (once to twice daily), which can hinder female convenience and adherence to treatment, particularly when undergoing multiple weeks of treatment (required to administer both antibiotic and probiotics). In this project we will use 3D printing and computational modeling, iteratively enabled by functional investigation of prototype scaffolds in vitro and in vivo, to design long-acting products that sustain therapeutic delivery, while enabling phased-delivery of antibiotics and probiotics to the female reproductive tract. Our team brings together female reproductive tract-specific expertise in delivery vehicle design, computational modeling, and preclinical BV models. The ultimate goal is to use 3D-bioprinting to incorporate different device compartments, which sequentially release antibiotics that target anaerobic overgrowth, followed by live probiotics that restore balance back in favor of vaginal lactobacilli. In Aim 1, we will design and characterize 3D-printed silicone scaffolds that sustain antibiotic-only delivery. Aim 2 will design and evaluate 3D-printed silicone and gelatin alginate composites that sequentially release antibiotics followed by probiotics, providing a “1-2 punch” strategy to kill BV bacteria and provide a ‘healthy’ Lactobacillus alternative. Each aim will focus first on a materials-based characterization of Met-containing silicone (1A) or Met-silicone probiotic-gelatin alginate composites (2A). Measurements from in vitro release experiments will be used to develop and test computational models that predict the delivery of antibiotic (1B) or dual agents (2B) in a “virtual female reproductive tract” and ultimately in a mouse co-infection model. We will evaluate Met-silicone (1C) and Met-silicone probiotic-gelatin alginate composites (2C) for cytotoxicity to the vaginal epithelium and ability to stimulate soluble proinflammatory mediators and downstream histopathology. In our mouse model, we will measure levels of viable Gardnerella and Prevotella recovered from vaginal and uterine tissues following treatment with blank or active agent- containing 3D-printed scaffolds. If successful, this project will support the development of multipurpose platforms to prevent and treat BV as well as other female reproductive tract applications.