Search

Degradable polar hydrophobic ionic polyurethanes (D-PHI) are an emerging class of biomaterials with particular significance for blood-contacting applications due to their immunomodulatory effects and highly customizable block chemistry. In this manuscript, D-PHI polymer was formulated as a nanoparticle excipient for the first time by inverse emulsion polymerization. The nanoparticles were optimized with consideration of diameter, surface charge, size variability, and yield as a delivery vehicle for a custom vascular therapeutic peptide. A layer-by-layer (LBL) surface modification technique using poly-L-lysine was integrated within the nanoparticle design to optimize therapeutic loading efficiency. Solvent pH played a pivotal role in emulsion micelle formation, LBL polymer secondary structure, and the polymer functional group interactions critical for high therapeutic loading. The resulting nanoparticle platform met target size (200 ± 20 nm), polydispersity (<0.07), and storage stability standards, was nontoxic, and did not affect therapeutic peptide bioactivity in vitro. Surface-modified D-PHI nanoparticles can be reproducibly manufactured at low cost, generating a highly customizable excipient platform suitable for delivery of biomolecular therapeutics. These nanoparticles have potential applications in vascular drug delivery via localized infusion, drug eluting stents, and drug-coated angioplasty balloons. Nanoscale excipients have become critical in the delivery of many therapeutics to enhance drug stability and targeted biodistribution through careful design of nanoparticle composition, surface chemistry, and size. This manuscript describes the development of a nanoparticle excipient derived from an immunomodulatory degradable polar hydrophobic ionic polyurethane, in combination with a layer-by-layer surface modification approach utilizing poly-L-lysine, to transport a mimetic peptide targeting smooth muscle cell migration in vascular disease. The nanoparticle platform draws on the effect of pH to maximize drug loading and tailor particle properties. The low cost and easily reproducible system presents a highly customizable platform that can be adapted for therapeutic delivery across a wide range of clinical indications. [Display omitted] [ABSTRACT FROM AUTHOR]

The study aims to assess the safety and effectiveness of BoneTape™, a new resorbable bone fixation device, using a zygomatic fracture model in rabbits. The study followed BoneTape™ samples and control (sham) groups over 2-, 6-, and 12-week periods post-zygomaticomaxillary (ZM) osteotomy and zygomaticofrontal (ZF) disarticulation. The osteotomized segments were analyzed for bone healing, inflammatory response, and tissue healing. µCT imaging and histological analysis were used to examine the axial alignment, offset, and quality of new bone formation. BoneTape™ samples demonstrated enhanced maintenance of the initial intraoperative positioning, reduced axial offset, and better alignment when compared with the control group, enabling stable bone healing under physiological loading conditions. Complete union was observed at 12-weeks in both groups. The BoneTape™ group experienced minimal immune and tissue reactions, classically associated with wound healing, and showed an increased number of giant cells at 6 and 12-weeks. BoneTape™ represents a promising advancement in osteosynthesis, demonstrating efficacy in maintaining stable zygomatic reconstruction and eliciting minimal immune response in a rabbit model. This study introduces BoneTape™ as a disruptive solution specifically designed for clinical application in cranio-maxillofacial fracture fixation, with the potential to eliminate the use of over-engineered solutions while offering benefits such as ease of application and fewer biologically disruptive steps. [ABSTRACT FROM AUTHOR]

The ex vivo endothelialization of small diameter vascular prostheses can prolong their patency. Here, we demonstrate that heterotypic interactions between human adipose tissue-derived endothelial cells and perivascular cells can be exploited to accelerate the endothelialization of an electrospun ionomeric polyurethane scaffold. The scaffold was used to physically separate endothelial cells from perivascular cells to prevent their diffuse neo-intimal hyperplasia and spontaneous tubulogenesis, yet enable their paracrine cross-talk to accelerate the integration of the endothelial cells into a temporally stable endothelial lining of a continuous, elongated, and aligned morphology. Perivascular cells stimulated endothelial basement membrane protein production and suppressed their angiogenic and inflammatory activation to accelerate this biomimetic morphogenesis of the endothelium. These findings demonstrate the feasibility and underscore the value of exploiting heterotypic interactions between endothelial cells and perivascular cells for the fabrication of an endothelial lining intended for small diameter arterial reconstruction. Adipose tissue is an abundant, accessible, and uniquely dispensable source of endothelial cells and perivascular cells for vascular tissue engineering. While their spontaneous self-assembly into microvascular networks is routinely exploited for the vascularization of engineered tissues, it threatens the temporal stability of an endothelial lining intended for small diameter arterial reconstruction. Here, we demonstrate that an electrospun polyurethane scaffold can be used to physically separate endothelial cells from perivascular cells to prevent their spontaneous capillary morphogenesis, yet enable their cross-talk to promote the formation of a stable endothelium. Our findings demonstrate the feasibility of engineering an endothelial lining from human adipose tissue, poising it for the rapid ex vivo endothelialization of small diameter vascular prostheses in an autologous, patient-specific manner. [Display omitted] [ABSTRACT FROM AUTHOR]

New functional materials for engineering gingival tissue are still in the early stages of development. Materials for such applications must maintain volume and have advantageous mechanical and biological characteristics for tissue regeneration, to be an alternative to autografts, which are the current benchmark of care. In this work, methacrylated gelatin (GelMa) was photocrosslinked with synthetic immunomodulatory methacrylated divinyl urethanes and defined monomers to generate composite scaffolds. Using a factorial design, with the synthetic monomers of a degradable polar/hydrophobic/ionic polyurethane (D-PHI) and GelMa, composite materials were electrospun with polycarbonate urethane (PCNU) and light-cured in-flight. The materials had significantly different relative hydrophilicities, with unique biodegradation profiles associated with specific formulations, thereby providing good guidance to achieving desired mechanical characteristics and scaffold resorption for gingival tissue regeneration. In accelerated esterase/collagenase degradation models, the new materials exhibited an initial rapid weight loss followed by a more gradual rate of degradation. The degradation profile allowed for the early infiltration of human adipose-derived stromal/stem cells, while still enabling the graft's structural integrity to be maintained. In conclusion, the materials provide a promising candidate platform for the regeneration of oral soft tissues, addressing the requirement of viable tissue infiltration while maintaining volume and mechanical integrity. There is a need for the development of more functional and efficacious materials for the treatment of gingival recession. To address significant limitations in current material formulations, we sought to investigate the development of methacrylated gelatin (GelMa) and oligo-urethane/methacrylate monomer composite materials. A factorial design was used to electrospin four new formulations containing four to five monomers. Synthetic immunomodulatory monomers were crosslinked with GelMa and electrospun with a polycarbonate urethane resulting in unique mechanical properties, and resorption rates which align with the original design criteria for gingival tissue engineering. The materials may have applications in tissue engineering and can be readily manufactured. The findings of this work may help better direct the efforts of tissue engineering and material manufacturing. [Display omitted] [ABSTRACT FROM AUTHOR]