On-Demand Guided Bone Regeneration with Microbial Protection of Ornamented SPU Scaffold with Bismuth-Doped Single Crystalline Hydroxyapatite: Augmentation and Cartilage Formation

Abstract

Guided bone regeneration (GBR) scaffolds are futile in many clinical applications due to infection problems. In this work, we fabricated GBR with an anti-infective scaffold by ornamenting 2D single crystalline bismuth-doped nanohydroxyapatite (Bi-nHA) rods onto segmented polyurethane (SPU). Bi-nHA with high aspect ratio was prepared without any templates. Subsequently, it was introduced into an unprecedented synthesized SPU matrix based on dual soft segments (PCL-b-PDMS) of poly(ε-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, undoped pristine nHA rods were also ornamented into it. The enzymatic ring-opening polymerization technique was adapted to synthesize soft segments of PCL-b-PDMS copolymers of SPU. Structure elucidation of the synthesized polymers is done by nuclear magnetic resonance spectroscopy. Sparingly, Bi-nHA ornamented scaffolds exhibit tremendous improvement (155%) in the mechanical properties with excellent antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast cells (in vitro), the scaffolds were implanted in rabbits by subcutaneous and intraosseous (tibial) sites. Various histological sections reveal the signatures of early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks of the critical defects filled with ornamented scaffold compared to SPU scaffold. This implies osteogenic potential and ability to provide an adequate biomimetic microenvironment for mineralization for GBR of the scaffolds. Organ toxicity studies further confirm that no tissue architecture abnormalities were observed in hepatic, cardiac, and renal tissue sections. This finding manifests the feasibility of fabricating a mechanically adequate nanofibrous SPU scaffold by a biomimetic strategy and the advantages of Bi-nHA ornamentation in promoting osteoblast phenotype progression with microbial protection (on-demand) for GBR applications.

The Treatment Effect of Highly Biocompatible Bismuth/ strontium/hydroxyapatite/chitosan for Osteosarcoma, Bacterial and Bone Defects

“…on the other hand, Bi interacts strongly with the the DNA, protein, which exist in bacteria, and interacts with sulfurphosphorus compounds exist in the outer membrane proteins, affect the respiratory chain response. Finally, This mechanism leads to cell death, hinders the synthesis of adenosine triphosphate (ATP), prevents cell wall synthesis, and inhibits a variety of enzymes, including urease, catalase and lipase [45].…”

Calcium Phosphate as a Key Material for Socially Responsible Tissue Engineering

“…This makes CAP capable of accommodating more than a half of all the elements of the Periodic Table [ 62 ]. In the case of HAP, for example, phosphate groups can be readily substituted with groups such as carbonate (B-type HAP) [ 63 ], selenite [ 64 ], vanadate [ 65 ], silicate [ 66 ], and others; calcium ions can be substituted with cations ranging in atomic weight from as light as lithium [ 67 ] to as heavy as bismuth [ 68 ], thorium [ 69 ], and uranium [ 70 ]; also hydroxyl groups can be substituted by ions as small as fluoride [ 71 ] and as large as carbonate (A-type HAP) [ 72 ]. The ease with which these substitutions could be made through simple co-precipitation reactions has led to a large body of research—albeit not very imaginative and somewhat trivial at times—on ion-substituted CAPs and their effects on bioactivity, antimicrobial activity and other biological properties of interest.…”

Synthesis and Characterization of Polycaprolactone-Based Polyurethanes for the Fabrication of Elastic Guided Bone Regeneration Membrane

“…However, the membranes were not porous, which is not beneficial to cell attachments. Recently, polyurethane membranes made of PCL, PDMS, and bismuth-doped nanohydroxyapatites were prepared [ 11 ]. The incorporation of the PDMS segment into the polymer backbone, however, may cause long-term harm to the body.…”