title: Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues.
abstract: Composite biomaterials comprising nanostructured hydroxyapatite (HAp) have an enormous potential for natural bone tissue reparation, filling and augmentation. Chitosan (Ch) as a naturally derived polymer has many physicochemical and biological properties that make it an attractive material for use in bone tissue engineering. On the other hand, poly-D,L-lactide-co-glycolide (PLGA) is a synthetic polymer with a long history of use in sustained drug delivery and tissue engineering. However, while chitosan can disrupt the cell membrane integrity and may induce blood thrombosis, PLGA releases acidic byproducts that may cause tissue inflammation and interfere with the healing process. One of the strategies to improve the biocompatibility of Ch and PLGA is to combine them with compounds that exhibit complementary properties. In this study we present the synthesis and characterization, as well as in vitro and in vivo analyses of a nanoparticulate form of HAp coated with two different polymeric systems: (a) Ch and (b) a Ch-PLGA polymer blend. Solvent/non-solvent precipitation and freeze-drying were used for synthesis and processing, respectively, whereas thermogravimetry coupled with mass spectrometry was used for phase identification purposes in the coating process. HAp/Ch composite particles exhibited the highest antimicrobial activity against all four microbial strains tested in this work, but after the reconstruction of the bone defect they also caused inflammatory reactions in the newly formed tissue where the defect had lain. Coating HAp with a polymeric blend composed of Ch and PLGA led to a decrease in the reactivity and antimicrobial activity of the composite particles, but also to an increase in the quality of the newly formed bone tissue in the reconstructed defect area.
authors.affiliation: Institute of Technical Sciences of the Serbian Academy of Science and Arts, Knez Mihailova 35/IV, P.O. Box 377, 11000 Belgrade, Serbia.
authors.forename: Nenad
authors.initials: N
authors.lastname: Ignjatović
authors.affiliation: Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, College of Engineering and College of Medicine, University of Illinois at Chicago, Chicago, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Wu
authors.affiliation: University of Niš, Faculty of Medicine, Clinic of Stomatology, Department of Prosthodontics, Bulevar Zorana Djindjica 81, 18000 Niš, Serbia.
authors.forename: Zorica
authors.initials: Z
authors.lastname: Ajduković
authors.affiliation: University of Niš, Faculty of Science and Mathematics, Department of Biology and Ecology, Višegradska 33, P. O. Box 224, 18000 Niš, Serbia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Mihajilov-Krstev
authors.affiliation: Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, College of Engineering and College of Medicine, University of Illinois at Chicago, Chicago, USA.
authors.forename: Vuk
authors.initials: V
authors.lastname: Uskoković
authors.affiliation: Institute of Technical Sciences of the Serbian Academy of Science and Arts, Knez Mihailova 35/IV, P.O. Box 377, 11000 Belgrade, Serbia. Electronic address: dragan.uskokovic@itn.sanu.ac.rs.
authors.forename: Dragan
authors.initials: D
authors.lastname: Uskoković
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration / Q000187:drug effects; D002460:Cell Line; D048271:Chitosan / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D048271:Chitosan; D017886:Durapatite
keywords: Antimicrobial activity; Bone regeneration; Chitosan; Hydroxyapatite; PLGA; TGA-on line MS