title: Functionalized carbon nanotube reinforced scaffolds for bone regenerative engineering: fabrication, in vitro and in vivo evaluation.
abstract: Designing biodegradable scaffolds with bone-compatible mechanical properties has been a significant challenge in the field of bone tissue engineering and regenerative engineering. The objective of this work is to improve the polymeric scaffold's mechanical strength by compositing it with mechanically superior carbon nanotubes. Poly(lactide-co-glycolide) (PLGA) microsphere scaffolds exhibit mechanical properties in the range of human cancellous bone. On the other hand, carbon nanotubes have outstanding mechanical properties. The aim of this study is to improve further the mechanical strength of PLGA scaffolds such that they may be applicable for a wide range of load-bearing repair and regeneration applications. We have formed composite microspheres of PLGA containing pristine and modified (with hydroxyl (OH), carboxylic acid (COOH)) multi-walled carbon nanotubes (MWCNTs), and fabricated them into three-dimensional porous scaffolds. Results show that by adding only 3% MWCNTs, the compressive strength and modulus was significantly increased (35 MPa, 510.99 MPa) compared to pure PLGA scaffolds (19 MPa and 166.38 MPa). Scanning electron microscopy images showed excellent cell adhesion and proliferation. In vitro studies exhibited good cell viability, proliferation and mineralization. The in vivo study, however, indicated differences in inflammatory response throughout the 12 weeks of implantation, with OH-modified MWCNTs having the least response, followed by unmodified and COOH-modified exhibiting a more pronounced response. Overall, our results show that PLGA scaffolds containing water-dispersible MWCNTs are mechanically stronger and display good cellular and tissue compatibility, and hence are potential candidates for load-bearing bone tissue engineering.
authors.affiliation: Institute for Regenerative Engineering, University of Connecticut Health Center, Farmington, CT 06032, USA. Materials Science & Engineering, University of Connecticut, Storrs, CT 06269, USA. Raymond and Beverly Sackler Center for Biomedical, Biological, Physical and Engineering Sciences Center.
authors.forename: Paiyz E
authors.initials: PE
authors.lastname: Mikael
authors.forename: Ami R
authors.initials: AR
authors.lastname: Amini
authors.forename: Joysurya
authors.initials: J
authors.lastname: Basu
authors.forename: M
authors.initials: M
authors.lastname: Josefina Arellano-Jimenez
authors.forename: Cato T
authors.initials: CT
authors.lastname: Laurencin
authors.forename: Mary M
authors.initials: MM
authors.lastname: Sanders
authors.forename: C
authors.initials: C
authors.lastname: Barry Carter
authors.forename: Syam P
authors.initials: SP
authors.lastname: Nukavarapu
mesh_terms: D016475:3T3 Cells; D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis; D001826:Body Fluids / Q000737:chemistry; D001861:Bone Regeneration / Q000502:physiology*; D049109:Cell Proliferation / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D019245:Compressive Strength; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D051379:Mice; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000295:instrumentation; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D037742:Nanotubes, Carbon; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid