Bioactive Cellulose Nanocrystal-Poly(epsilon-Caprolactone) Nanocomposites for Bone Tissue Engineering Applications

dc.contributor.authorHong, Jung Kien
dc.contributor.authorCooke, Shelley L.en
dc.contributor.authorWhittington, Abby R.en
dc.contributor.authorRoman, Marenen
dc.contributor.departmentMacromolecules Innovation Instituteen
dc.contributor.departmentMaterials Science and Engineeringen
dc.contributor.departmentChemical Engineeringen
dc.contributor.departmentSustainable Biomaterialsen
dc.description.abstract3D-printed bone scaffolds hold great promise for the individualized treatment of critical-size bone defects. Among the resorbable polymers available for use as 3D-printable scaffold materials, poly(epsilon-caprolactone) (PCL) has many benefits. However, its relatively low stiffness and lack of bioactivity limit its use in load-bearing bone scaffolds. This study tests the hypothesis that surface-oxidized cellulose nanocrystals (SO-CNCs), decorated with carboxyl groups, can act as multi-functional scaffold additives that (1) improve the mechanical properties of PCL and (2) induce biomineral formation upon PCL resorption. To this end, an in vitro biomineralization study was performed to assess the ability of SO-CNCs to induce the formation of calcium phosphate minerals. In addition, PCL nanocomposites containing different amounts of SO-CNCs (1, 2, 3, 5, and 10 wt%) were prepared using melt compounding extrusion and characterized in terms of Young's modulus, ultimate tensile strength, crystallinity, thermal transitions, and water contact angle. Neither sulfuric acid-hydrolyzed CNCs (SH-CNCs) nor SO-CNCs were toxic to MC3T3 preosteoblasts during a 24 h exposure at concentrations ranging from 0.25 to 3.0 mg/mL. SO-CNCs were more effective at inducing mineral formation than SH-CNCs in simulated body fluid (1x). An SO-CNC content of 10 wt% in the PCL matrix caused a more than 2-fold increase in Young's modulus (stiffness) and a more than 60% increase in ultimate tensile strength. The matrix glass transition and melting temperatures were not affected by the SO-CNCs but the crystallization temperature increased by about 5.5 degrees C upon addition of 10 wt% SO-CNCs, the matrix crystallinity decreased from about 43 to about 40%, and the water contact angle decreased from 87 to 82.6 degrees. The abilities of SO-CNCs to induce calcium phosphate mineral formation and increase the Young's modulus of PCL render them attractive for applications as multi-functional nanoscale additives in PCL-based bone scaffolds.en
dc.description.notesThis project was supported in part by the National Science Foundation under grant number DMR-0907567, the U.S. Department of Agriculture under grant numbers 2010-65504-20429, the Virginia Agricultural Experiment Station, the Hatch Multistate Program of the National Institute of Food and Agriculture of the U.S. Department of Agriculture, and the Institute for Critical Technology and Applied Science.en
dc.description.sponsorshipNational Science FoundationNational Science Foundation (NSF) [DMR-0907567]; U.S. Department of AgricultureUnited States Department of Agriculture (USDA) [2010-65504-20429]; Virginia Agricultural Experiment Station; Hatch Multistate Program of the National Institute of Food and Agriculture of the U.S. Department of Agriculture; Institute for Critical Technology and Applied Scienceen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.subjectcellulose nanocrystalen
dc.subjectbone scaffolden
dc.titleBioactive Cellulose Nanocrystal-Poly(epsilon-Caprolactone) Nanocomposites for Bone Tissue Engineering Applicationsen
dc.title.serialFrontiers in Bioengineering and Biotechnologyen
dc.typeArticle - Refereeden
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