Browsing by Subject "Tissue scaffolds"

Now showing 1 - 3 of 3
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    Biomedical Engineering Advancements after Management of Myelomeningocele Study (MOMS): A Narrative Review
    (University of Pittsburgh Library System, 2022) Campbell, Natalie C.; Trippel, Stephen B.; Nauman, Eric A.; Orthopaedic Surgery, School of Medicine
    Spina bifida is a neural tube defect resulting from an incomplete closure of the caudal neuropore. The most debilitating form of spina bifida, myelomeningocele (MMC), can present with Chiari II malformation with concomitant hydrocephalus, bowel and bladder abnormalities, and impaired motor function of the lower limbs. The incidence rate of spina bifida is 3.4 per 10,000 live births reported within the US. Advancements in the standard therapy, namely prenatal intervention pioneered by the Management of Myelomeningocele Study (MOMS), have aimed to reduce maternal and fetal complications, and yet complications were increased, calling for the need of further improvements. Beyond current standard interventions for MMC, the most promising developments have employed various biomedical methods ranging from isolated stem cell injections to biodegradable scaffold patches. These scaffolds can be biologic or synthetic and are often incorporated with bioactive proteins or stem cells. This review discusses the benefits and limitations of post-MOMS era biomedical engineering intervention articles found in 3 medical and biomedical databases consisting of systematic reviews, meta-analyses, randomized control trials, and experimental studies. After analysis of the advancements and limitations of these studies, an engineered synthetic biodegradable scaffold seeded with bioactive proteins and stem cells create a superior scaffold possessing watertight impermeability and cytocompatibility for successful coverage and host integration with minimal inflammation. Coupled with minimally invasive intra-amniotic injection delivery, an earlier mitigation could further prevent progression of poor neurologic outcomes, and possibly even regenerate neuronal tissue in patients with MMC.
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    Engineered collagen polymeric materials create noninflammatory regenerative microenvironments that avoid classical foreign body responses
    (Royal Society of Chemistry, 2023) Morrison, Rachel A.; Brookes, Sarah; Puls, Theodore J.; Cox, Abigail; Gao, Hongyu; Liu, Yunlong; Voytik-Harbin, Sherry L.; Medical and Molecular Genetics, School of Medicine
    The efficacy and longevity of medical implants and devices is largely determined by the host immune response, which extends along a continuum from pro-inflammatory/pro-fibrotic to anti-inflammatory/pro-regenerative. Using a rat subcutaneous implantation model, along with histological and transcriptomics analyses, we characterized the tissue response to a collagen polymeric scaffold fabricated from polymerizable type I oligomeric collagen (Oligomer) in comparison to commercial synthetic and collagen-based products. In contrast to commercial biomaterials, no evidence of an immune-mediated foreign body reaction, fibrosis, or bioresorption was observed with Oligomer scaffolds for beyond 60 days. Oligomer scaffolds were noninflammatory, eliciting minimal innate inflammation and immune cell accumulation similar to sham surgical controls. Genes associated with Th2 and regulatory T cells were instead upregulated, implying a novel pathway to immune tolerance and regenerative remodeling for biomaterials.
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    Visible Light Cured Thiol-vinyl Hydrogels with Tunable Gelation and Degradation
    (2014) Hao, Yiting; Berbari, Edward J.; Lin, Chien-Chi; Xie, Dong; Chu, Tien-Min
    Hydrogels prepared from photopolymerization have been widely used in many biomedical applications. Ultraviolet (200-400 nm) or visible (400-800 nm) light can interact with light-sensitive compounds called photoinitiators to form radical species that trigger photopolylmerization. Since UV light has potential to cause cell damage, visible light-mediated photopolymerization has attracted much attention. The conventional method to fabricate hydrogels under visible light exposure requires usage of co-initiator triethanolamine (TEA) at high concentration (∼200 mM), which reduces cell viability. Therefore, the first objective of this thesis was to develop a new method to form poly(ethylene glycol)-diacrylate (PEGDA) hydrogel without using TEA. Specifically, thiol-containing molecules (e.g. dithiothreitol or cysteine-containing peptides) were used to replace TEA as both co-initiator and crosslinker. Co-monomer 1-vinyl-2-pyrrolidinone (NVP) was used to accelerate gelation kinetics. The gelation rate could be tuned by changing the concentration of eosinY or NVP. Variation of thiol concentration affected degradation rate of hydrogels. Many bioactive motifs have been immobilized into hydrogels to enhance cell attachment and adhesion in previous studies. In this thesis, pendant peptide RGDS was incorporated via two methods with high incorporation efficiency. The stiffness of hydrogels decreased when incorporating RGDS. The second objective of this thesis was to fabricate hydrogels using poly(ethylene glycol)-tetra-acrylate (PEG4A) macromer instead of PEGDA via the same step-and-chain-growth mixed mode mechanism. Formation of hydrogels using PEGDA in this thesis required high concentration of macromer (∼10 wt.%). Since PEG4A had two more functional acrylate groups than PEGDA, hydrogels could be fabricated using lower concentration of PEG4A (∼4 wt.%). The effects of NVP concentration and thiol content on hydrogel properties were similar to those on PEGDA hydrogels. In addition, the functionality and chemistry of thiol could also affect hydrogel properties.