title: In Vitro and in Vivo Studies of Novel Poly(D,L-lactic acid), Superhydrophilic Carbon Nanotubes, and Nanohydroxyapatite Scaffolds for Bone Regeneration.
abstract: Poly(D,L-lactide acid, PDLLA) has been researched for scaffolds in bone regeneration. However, its hydrophobocity and smooth surface impedes its interaction with biological fluid and cell adhesion. To alter the surface characteristics, different surface modification techniques have been developed to facilitate biological application. The present study compared two different routes to produce PDLLA/superhydrophilic vertically aligned carbon nanotubes:nanohydroxyapatite (PDLLA/VACNT-O:nHAp) scaffolds. For this, we used electrodeposition and immersion in simulated body fluid (SBF). Characterization by goniometry, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy confirmed the polymer modifications, the in vitro bioactivity, and biomineralization. Differential scanning calorimetry and thermal gravimetric analyses showed that the inclusion of VACNT-O:nHA probably acts as a nucleating agent increasing the crystallization rate in the neat PDLLA without structural alteration. Our results showed the formation of a dense nHAp layer on all scaffolds after 14 days of immersion in SBF solution; the most intense carbonated nHAp peaks observed in the PDLLA/VACNT-O:nHAp samples suggest higher calcium precipitation compared to the PDLLA control. Both cell viability and alkaline phosphatase assays showed favorable results, because no cytotoxic effects were present and all produced scaffolds were able to induce detectable mineralization. Bone defects were used to evaluate the bone regeneration; the confocal Raman and histological results confirmed high potential for bone applications. In vivo study showed that the PDLLA/VACNT-O:nHAp scaffolds mimicked the immature bone and induced bone remodeling. These findings indicate surface improvement and the applicability of this new nanobiomaterial for bone regenerative medicine.
authors.forename: Idalia A W B
authors.initials: IA
authors.lastname: Siqueira
authors.affiliation: ‡Multidisciplinary Center for Biological Investigation on Laboratory Animal Science (CEMIB), State University of Campinas, Campinas SP 13083-970, Sao Paulo, Brazil.
authors.forename: Marcus Alexandre F
authors.initials: MA
authors.lastname: Corat
authors.affiliation: §Department of Cariology, Restorative Sciences and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
authors.forename: Bruno das Neves
authors.initials: Bd
authors.lastname: Cavalcanti
authors.affiliation: ∥Department of Materials Engineering, Federal University of Sao Carlos, Sao Carlos SP 13565-905, Sao Paulo, Brazil.
authors.forename: Wilson Alves
authors.initials: WA
authors.lastname: Ribeiro Neto
authors.forename: Airton Abrahao
authors.initials: AA
authors.lastname: Martin
authors.affiliation: ∥Department of Materials Engineering, Federal University of Sao Carlos, Sao Carlos SP 13565-905, Sao Paulo, Brazil.
authors.forename: Rosario Elida Suman
authors.initials: RE
authors.lastname: Bretas
authors.forename: Fernanda Roberta
authors.initials: FR
authors.lastname: Marciano
authors.forename: Anderson Oliveira
authors.initials: AO
authors.lastname: Lobo
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000577:Amides / Q000032:analysis; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D002254:Carbonates / Q000032:analysis; D002448:Cell Adhesion / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003460:Crystallization; D017886:Durapatite / Q000494:pharmacology*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D019344:Lactic Acid / Q000494:pharmacology*; D008297:Male; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D010316:Particle Size; D010710:Phosphates / Q000032:analysis; D011091:Polyesters; D011108:Polymers / Q000494:pharmacology*; D011392:Proline / Q000032:analysis; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000577:Amides; D002254:Carbonates; D037742:Nanotubes, Carbon; D010710:Phosphates; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D017886:Durapatite; D011392:Proline; D000469:Alkaline Phosphatase
keywords: PDLLA; bioactivity; bone regeneration; carbon nanotube; nanohydroxyapatite; porous scaffold