title: Roles of hydroxyapatite allocation and microgroove dimension in promoting preosteoblastic cell functions on photocured polymer nanocomposites through nuclear distribution and alignment.
abstract: This study clarifies how hydroxyapatite (HA) allocation and microgroove dimension affect mouse preosteoblastic MC3T3-E1 cell functions on microgrooved substrates of polymer nanocomposites. Using replica molding from micromachined silicon wafer templates, we fabricated photocured poly(ε-caprolactone) triacrylate (PCLTA)/HA nanocomposite substrates with parallel microgrooves (two groove widths of 5 and 15 μm and one groove depth of 5 μm). Four types of microgrooved substrates were made: "homogeneous" ones of PCLTA and PCLTA/HA with uniform distribution and two "heterogeneous" laminated microgrooved substrates with HA only in the PCLTA matrix in the ridges or bottom. These substrates were used to regulate MC3T3-E1 cell attachment, proliferation, alignment, nuclear circularity and distribution, and mineralization. MC3T3-E1 cell attachment and proliferation were much higher on the microgrooved substrates of PCLTA/HA than on those of PCLTA, in particular, on the 5 μm wide microgrooved substrate with PCLTA/HA ridges and PCLTA bottom. The shape and distribution of MC3T3-E1 cytoskeleton and nuclei were altered by the substrate topography and HA allocation. For 5 μm wide heterogeneous microgrooved substrates with HA only in the ridges, MC3T3-E1 cells exhibited better spreading perpendicular to the microgrooves but tended to extend along the microgrooves containing HA in the bottom. The widest cells and the roundest/largest cell nuclei were observed on the heterogeneous substrate with PCLTA/HA ridges, while the narrowest cells with the best elongation were found on the homogeneous PCLTA/HA substrate. The trend in MC3T3-E1 cell mineralization on the substrates was consistent with that in cell/nuclear elongation. Osteocalcin mRNA expression was significantly higher on the PCLTA/HA substrates than on the PCLTA ones and also on the microgrooved substrates of PCLTA/HA than on the flat ones, regardless of the groove width of 5 or 15 μm.
authors.affiliation: Department of Materials Science and Engineering, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Henry
authors.forename: Lei
authors.initials: L
authors.lastname: Cai
authors.forename: Xifeng
authors.initials: X
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Jingyan
authors.initials: J
authors.lastname: Dong
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.forename: Zaiqin
authors.initials: Z
authors.lastname: Wang
authors.forename: Shanfeng
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D002209:Caprolactam / Q000737:chemistry / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D017886:Durapatite / Q000737:chemistry*; D005786:Gene Expression Regulation / Q000187:drug effects; D008027:Light; D051379:Mice; D008903:Minerals / Q000378:metabolism; D053761:Nanocomposites / Q000737:chemistry*; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D023822:Tissue Engineering
chemical_list: D008903:Minerals; D002209:Caprolactam; C000362:capron; D017886:Durapatite