Heterotopic ossification (HO), or the formation of pathologic bone tissue outside the skeleton, is a debilitating condition that primarily arises following traumatic orthopedic injuries. These bony nodules often develop after blast injuries or at sites of limb amputation and can cause significant pain, joint immobilization, or soft tissue damage. Since HO does not regress over time, patients with advanced heterotopic bone formation typically require extensive surgeries to relieve symptoms. Though some preventative treatments for HO such as radiotherapy or bisphosphonate drug treatment have shown promise, these interventions are inconsistent and often hinder normal tissue healing. Based on these limitations with current HO prevention strategies, this work describes the development injectable hydrogels that can be prophylactically administered directly to an injury site to both reprogram the local inflammatory tissue environment and remove calcium ion precursors that form heterotopic bone. These gels are made with poly(aspartic acid) (PASA), a synthetic polypeptide that is highly hydrophilic, biocompatible, easily degraded by proteases, and features a strong affinity for calcium ions. In biomedical applications, PASA’s attraction to calcium has often been employed to create drug delivery vehicles that can target calcified bone tissue but has never been explored to prevent biological calcium deposition within the body. Here, thiol-functionalized PASA was combined with a poly(ethylene glycol) (PEG) 4-arm macromer featuring thiol-reactive maleimide end groups (PEG-MAL) to generate fast-gelling hydrogels. These hydrogels were first incubated in either saline or a collagenase solution (3mg/mL) over 10 days and demonstrated specific enzymatic biodegradability. Next, the antioxidant compound 4-amine TEMPO was covalently conjugated onto the PASA precursor polymer and demonstrated significant radical scavenging using a a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Finally, PASA hydrogels or non-PASA gel controls were incubated with calcium chloride solutions to assess calcium ion scavenging using an o-Cresothalein assay. Though passive diffusion allowed some calcium to be retained in the non-PASA controls, there was a significant PASA dose-dependent increase in calcium scavenging in the bioactive hydrogel formulations. These preliminary data confirm our fundamental hypothesis of PASA hydrogel calcium scavenging and motivate the further development of this platform. 

Glioblastoma multiforme (GBM), the most lethal form of primary brain cancer, employs various receptors to infiltrate the human brain and establish biological niches and resist chemotherapy. Despite the significance of CD44 and integrins in tumor invasion and drug resistance, prevailing in vitro GBM studies predominantly employ suspended tumor spheres or tumoroids without any scaffold. While this approach aids cancer stem cell maintenance, it constrains our comprehension of the extracellular matrix's role in tumorigenesis and the essential biochemical and biomechanical cues governing tumor progression and treatment resistance. Our study introduces a novel design that incorporates a bioprintable hydrogel consisting of Gelatin and hyaluronic acid. This carefully tailored composition enables the growth of cancer spheroids either in isolation or in co-culture with other cell types, including brain endothelial cells. Furthermore, the viscosity of the hydrogel has been optimized to maintain the spheroids well segregated during the bioprinting process, ensuring accurate positioning within the constructs. The hydrogel can be easily mixed with 3D spheroids and crosslinked through a brief UV-light treatment. The presented biofabrication approach seamlessly integrates with a high-throughput imaging-based approach, providing spatial insights into cancer progression in response to drug treatment. Our innovative hydrogel design offers a versatile and customizable platform with applications in cancer research and tissue engineering. Our results showcase the effectiveness of our bioprinting approach in preserving GBM spheroids without damage and generating complex microtissues including different ECM components and cell types including brain endothelial cells and astrocytes. Microscopic characterization of our biofabricated model reveals the retention of cancer stem cell markers within this 3D structure, a phenomenon typically lost in traditional Collagen I-based scaffolds. This advancement holds promise for unraveling intricate mechanisms governing GBM behavior, providing a more physiologically relevant platform for drug testing and furthering our understanding of tumor biology.

One of the leading causes of vision loss worldwide is age-related macular degeneration (AMD), affecting over 200 million individuals. This neurodegenerative disease is a burden to the healthcare system, coming in at $250 billion in global cost. AMD risk factors include progressive age, genetics, obesity, smoking, and race. Early-stage pathogenesis of AMD is the accumulation of reactive oxygen species (ROS) in aging tissue leading to retinal inflammation, known as dry AMD (dAMD). While infrequent, dAMD may progress to wet AMD (wAMD), which is choroidal neovascularization resulting in blood and fluid leakage, furthering permanent vision loss. Currently, there is no cure for AMD and treatment options predominantly target wAMD through invasive and frequent intravitreal injections. Only recently have potential new therapeutics for dAMD emerged, targeting the complement system, but these also require monthly intravitreal injections. To target dAMD and mitigate disease progression, a novel anti-inflammatory heme-bound human serum albumin (heme-albumin) complex was investigated. We hypothesize that heme-albumin will induce heme oxygenase-1 (HO-1) in retinal pigment epithelium (RPE) cells by catabolizing heme into carbon monoxide (CO) and biliverdin for antioxidant and anti-inflammatory properties, respectively. This protein complex has been encapsulated in polydopamine nanoparticles (PDA NPs) for sustained release as well as ROS scavenging. Heme-albumin demonstrated no significant cytotoxicity in human RPE cells, ARPE-19, and reduced oxidative stress in inflammatory and ROS models in vitro. PDA NPs loading heme-albumin showed sustained release for up to 6 months with a reduction in oxidative stress and minimal cytotoxicity. Successful cellular uptake of heme-albumin and loaded PDA NPs through flow cytometry was demonstrated alongside significant HO-1 expression in ARPE-19 cells. Through in vitro verification, we validate that heme-albumin loaded PDA NPs reduce oxidative stress and inflammation and has potential to serve as a sustained therapeutic for AMD. 

Platelet transfusions are used in prophylactic management of bleeding risks, as well as emergency management of acute surgical and traumatic bleeding. However, natural platelet products suffer from challenges of: (i) limited availability and portability, (ii) pathogenic contamination risks resulting in very short shelf-life (~5-7 days), and (iii) various biological side-effects. Current pathogen reduction technologies and approaches with temperature reduced (chilled, freeze-dried etc.) platelets have extended the shelf-life to a few weeks, but have not fully resolved the challenges of widespread availability both within and outside of hospitals (e.g. at point-of-injury), and the issues of variable hemostatic performance. In this framework, for over a decade our research has focused on developing nanoparticle-based technologies that modularly mimic, leverage and amplify platelet-mediated mechanisms of hemostasis. This R&D and commercialization endeavor is at the interface of nanomaterials, bioengineering and medicine, to create novel therapeutics directed at efficiently addressing and resolving challenges in bleeding management. The current talk will provide a brief background of the history and conceptualization of our ‘artificial platelet’ technologies, trainee contributions, IP development, translational advancement through academic research as well as through a biotech start-up (Haima Therapeutics), and the envisioned path to commercialization and clinical use.

This study combines gap electrospinning and electrolyte-assisted electrospinning techniques to develop a method for creating nanofiber membranes with controlled size and shape. The method utilizes syringe extrusion printing of a gel polymer electrolyte (GPE) solution to accurately focus electrospun nanofibers (ESNF). The printable GPE ink is formulated to ensure it possesses the necessary conductivity, shear-thinning, and thixotropic properties, in addition to being biocompatible for potential applications involving human cells. We have developed a gelatin-based GPE ink, enhanced with Laponite to improve shear-thinning properties and salts to increase conductivity. The ink's rheology and conductivity were thoroughly examined, with the latter measured using a custom developed four-point probe system for gels. These properties support the ink's use in precise ESNF membrane patterning with specific geometries on dielectric surfaces. A key part of our research is the assessment of the ink's biocompatibility, especially when in contact with human cells, using the Cell Counting Kit-8 (CCK-8) assay. This evaluation is crucial for confirming the material's suitability for biomedical applications. The CCK-8 assay results indicate that the GPE ink is compatible with cell viability, underscoring its potential use in areas such as regenerative medicine and tissue engineering. In summary, our work introduces a novel approach for the controlled preparation of ESNF membranes, supported by the development of a specialized GPE ink. The study's findings, particularly regarding biocompatibility, suggest that the ink could be a valuable material for biomedical engineering applications, although further research is needed to explore its full potential.

We have our first human implant with 3D Printed FibreTuff PAPC monofilament as a Dental Bone Grafting Material. The 3D Printed PAPC microporous cellular structure was autoclaved, prepared with antibiotics, customized and implanted on March 21, 2024. The dentist used the printed FibreTuff PAPC in replacement of existing Dental Bone Grafting Materials such as allograft, bio resorbable's and PEEK. There was good soft tissue coverage after 3 days demonstrating a very effective solution for quicker healing at a faster rate, lowering the chances for infection plus lowering dental costs. The patient is a 65 year old male. The patient will have a CT scan in a couple of weeks to show any bone bridging. There will be a case study written on the above bone grafting application in April 2024. It's very premature but believe the FDA will look at this implant as a DeNovo study. We are looking for more opportunities and collaboration for the $450 million market.