Browsing by Author "Almousa, Rashed"

Now showing 1 - 6 of 6
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    Hydrophilic polymer‐coated PVC surface for reduced cell and bacterial adhesions
    (Wiley, 2022) Almousa, Rashed; Wen, Xin; Na, Sungsoo; Anderson, Gregory; Xie, Dong; Biology, School of Science
    Hydrophilic polymers are very useful in biomedical applications. In this study, biocompatible polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) polymers end‐capped with succinimidyl groups were either modified or synthesised and attached to polyvinylchloride surfaces. The modified surfaces were evaluated with cell adhesion and bacterial adhesion. 3T3 mouse fibroblast cells and three bacteria species were used to evaluate surface adhesion activity. Results showed that the modified surface exhibited significantly reduced 3T3 cell adhesion with a 50%–69% decrease for PEG and a 64%–81% for PVP, as compared to unmodified polyvinylchloride. The modified surface also showed significantly reduced bacterial attachment with 22%–78%, 18%–76% and 20%– 75% decrease for PEG and 22%–76%, 18%–76% and 20%–73% for PVP to Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, as compared to unmodified polyvinylchloride. It seems that an appropriate chain length or molecular weight (neither the longest nor the shortest chain length) determines the lowest cell and bacterial adhesion in terms of PEG. On the other hand, a mixture of polymers with different chain lengths exhibited the lowest cell and bacterial adhesion in terms of PVP.
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    An improved dental composite with potent antibacterial function
    (Elsevier, 2019-07) Almousa, Rashed; Wen, Xin; Anderson, Gregory G.; Xie, Dong; Biomedical Engineering, School of Engineering and Technology
    A new BisGMA-based antibacterial dental composite has been formulated and evaluated. Compressive strength and bacterial viability were utilized to evaluate the formed composites. It was found that the new composite exhibited a significantly enhanced antibacterial function along with improved mechanical and physical properties. The bromine-containing derivative-modified composite was more potent in antibacterial activity than the chlorine-containing composite. The modified composites also exhibited an increase of 30–53% in compressive yield strength, 15–30% in compressive modulus, 15–33% in diametral tensile strength and 6–20% in flexural strength, and a decrease of 57–76% in bacterial viability, 23–37% in water sorption, 8–15% in shrinkage, 8–13% in compressive strength, and similar degree of conversion, than unmodified composite. It appears that this experimental composite may possibly be introduced to dental clinics as an attractive dental restorative due to its improved properties as well as enhanced antibacterial function.
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    Partially Demineralized Macroporous (PDM) Allografts for Cranial Tissue Engineering
    (Office of the Vice Chancellor for Research, 2015-04-17) Arman, Huseyin E.; Almousa, Rashed; Musgrove, Shamber; Syed, Javed; Wunderlin, Caitlin
    Decompressive Craniectomy is a cranial surgery where a large part of the cranial bone is removed in order to mitigate swelling in the brain tissue. Consequently, a scaffold biomaterial is required to substitute the lost bone. Ideal cranioplasty biomaterials should have the following features: fit the cranial defect and achieve complete closure, radiolucency, resistance to infections, no dilation with heat, resistance to biomechanical wear, pliability, and inexpensive. Partially Demineralized Macroporous (PDM) allografts exhibit such properties to correct these cranial defects. The main objectives of this study include: (1) examining the effects of demineralization and macroporosity formations on the mechanical and biological properties of allograft bone disks; (2) conducting finite element analysis (FEA) to stimulate the mechanical properties of the PDM allografts; and (3) evaluating the in vitro response of the PDM allografts utilizing pre-osteoblast cell lines. Tibias were harvested from Ossabaw mini-pigs and cylindrical cortical bone sections of 2 mm in thickness and 8 mm in diameter were obtained. Macropores of 600 micrometers in diameter were created to generate porosity levels of 0-40% in the bone disks. The bone disks were then demineralized in 14-wt% EDTA for 6 to 48 hours at 37℃. The relative stiffness was determined for each class using a material testing machine with a loading rate of 1 mm/min using a piston-on-ring set up. To analyze the deformation characteristics, FEA software LS-DYNA was employed. In order to understand the in vitro response, biocompatibility of PDM scaffolds were evaluated by culturing MC3T3-E1 cell lines where XTT and ALP assays were conducted. PDM allografts display the suitable stiffness required for cranial defects. The PDM allograft scaffolds aid in osteogenic proliferation and differentiation of pre-osteoblast cell lines in vitro. However, there will be further in vivo testing regarding the validity of PDM allografts in rat cranial defects. Mentor: Tien-Min Gabriel Chu, Department of Restorative DentistryDecompressive Craniectomy is a cranial surgery where a large part of the cranial bone is removed in order to mitigate swelling in the brain tissue. Consequently, a scaffold biomaterial is required to substitute the lost bone. Ideal cranioplasty biomaterials should have the following features: fit the cranial defect and achieve complete closure, radiolucency, resistance to infections, no dilation with heat, resistance to biomechanical wear, pliability, and inexpensive. Partially Demineralized Macroporous (PDM) allografts exhibit such properties to correct these cranial defects. The main objectives of this study include: (1) examining the effects of demineralization and macroporosity formations on the mechanical and biological properties of allograft bone disks; (2) conducting finite element analysis (FEA) to stimulate the mechanical properties of the PDM allografts; and (3) evaluating the in vitro response of the PDM allografts utilizing pre-osteoblast cell lines. Tibias were harvested from Ossabaw mini-pigs and cylindrical cortical bone sections of 2 mm in thickness and 8 mm in diameter were obtained. Macropores of 600 micrometers in diameter were created to generate porosity levels of 0-40% in the bone disks. The bone disks were then demineralized in 14-wt% EDTA for 6 to 48 hours at 37℃. The relative stiffness was determined for each class using a material testing machine with a loading rate of 1 mm/min using a piston-on-ring set up. To analyze the deformation characteristics, FEA software LS-DYNA was employed. In order to understand the in vitro response, biocompatibility of PDM scaffolds were evaluated by culturing MC3T3-E1 cell lines where XTT and ALP assays were conducted. PDM allografts display the suitable stiffness required for cranial defects. The PDM allograft scaffolds aid in osteogenic proliferation and differentiation of pre-osteoblast cell lines in vitro. However, there will be further in vivo testing regarding the validity of PDM allografts in rat cranial defects.
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    Polyurethane coated with polyvinylpyrrolidones via triazole links for enhanced surface fouling resistance
    (Wiley, 2021-12) Wen, Xin; Almousa, Rashed; Na, Sungsoo; Anderson, Gregory G.; Xie, Dong; Biomedical Engineering, School of Engineering and Technology
    Surfaces with hydrophilic and antimicrobial properties are very attractive for cardiovascular device-associated applications. The aim of this study was to prepare and coat a hydrophilic polymer containing a functional group capable of forming triazole functionality onto the surface of polyurethane (PU). The modified surfaces were assessed with cell adhesion, bacterial adhesion and bacterial viability. Mouse fibroblast cells (NIH-3T3) and three bacterial species were used for assessment. The results showed that the modified surface not only exhibited a significant reduction in cell adhesion with a 25%–59% decrease to mouse fibroblast but also showed a significant reduction in bacterial attachment with 26%–67%, 24%–61% and 23%–57% decrease to Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, as compared with original PU. Furthermore, the polymer-modified surface exhibited a significant antibacterial function by inhibiting bacterial growth with reduction of 49%–84%, 44%–79% and 53%–79% to S. aureus, E. coli and P. aeruginosa, respectively, as compared with original PU. These results indicate that covalent polymer attachment enhanced the antibacterial and antifouling properties of the PU surface.
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    A quaternary ammonium bromide-containing polymer for polyurethane surface modification
    (2019) Almousa, Rashed; Howard, Leah; Xie, Dong; Biomedical Engineering, School of Engineering and Technology
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    A self-cured glass-ionomer cement with improved antibacterial function and hardness
    (Wiley, 2020) Chen, Yong; Caneli, Gulsah; Almousa, Rashed; Hill, Kayla; Na, Sungsoo; Anderson, Gregory G.; Xie, Dong; Biology, School of Science
    A novel antimicrobial dental self-cured glass-ionomer cement has been developed and evaluated. Alumina filler particles were covalently coated with an antibacterial polymer and blended into a self-cured glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Results showed that the modified cements exhibited a significantly enhanced antibacterial activity along with improved surface hardness. Effects of antibacterial moiety content, alumina particle size and loading, and total filler content were investigated. It was found that increasing antibacterial moiety content, particle size and loading, and total filler content generally increased surface hardness. Increasing antibacterial moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size showed a negative impact on antibacterial activity. The leaching tests indicate no cytotoxicity produced from the modified cements to both bacteria and 3T3 mouse fibroblast cells.