Bone as a living tissue: the bone healing process (original) (raw)
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Biomedical Engineering Advances, 2022
Different biomaterials for bone regeneration have shown a lot of drawbacks, for allograft; the drawbacks are delayed incorporation, limited osteogenic, rejection of grafts, and risk of disease transmission; for xenograft, the drawbacks are delayed incorporation, limited osteogenic, more aggressive rejection of grafts, re-injury risks, and inadequate vascularization; and for autologous, the drawbacks are unpredictable resorption, donor site pain, limited availability, hematoma, variable quality, as well as inadequate vascularization. Future researchers have to keep these drawbacks in context to understand how they can deal with them to get the desired results. Nanohydroxyapatite nHA is a candidate material for multipurpose applications in biomedical industries such as bone regeneration and dental application due to its outstanding biocompatibility properties. Hydroxyapatite one of the most critical biomaterials is a major part of the mineral section of the teeth and bone. The remineralizing effect generated and offered by the nHA happens to be more useful for bone regeneration as compared to conventional fluoride. The purpose of this review is to highlight the various beneficial mechanical and morphological properties of a nano-hydroxyapatite (nHA) that is majorly utilized in bone regeneration in recent years. Nanohydroxyapatite has unique biomaterials and biostructures that make bone regeneration possible thus its wide applications in medicine. In addition to that, it also has inorganic and organic components that make it biologically feasible to be used in bone regeneration. This review also found that nHA comes with various unique kind of properties like it does not induce any inflammation or toxicity, has the capacity to chemically bond with the bone, and has the property of stimulating the growth of the bones. Different process techniques are used with nHA to achieve bone regeneration and with these processes, morphological characteristics and effects of microstructures are also explored. Regenerative medicine therefore considers nHA as being essential in enhancing the self-renewal ability of bones, and if a proper methodology is used with mechanical and morphological characterization, then the effects of nHA can be amazing for bone regeneration. The properties of nHA are good enough not only for the remineralizing of the bone but also for the growth of the tissues to keep them healthy and performing better against sensitivity as well as any kind of stress or strain. In addition, the paper also reviewed that when the bone regeneration process is conducted, it has to deal with a variety of requirements to achieve the desired results. The first required component is an osteoinductive signal, and the second required component is an insoluble substratum which is a scaffold when it comes to inducting formation of the new bone. The third required component is host recipient cells, which have the capability to differentiate the bone cells when responding to the osteoinductive signals. It is also found that nHAp sizes of bones are better than any other sizes because they come up with so many qualities and properties such as having nonimmunogenic properties, noninflammatory behavior, biocompatibility, osteoinductive capacity, as well as, high osteoconductive.
Nanohydroxyapatite shape and its potential role in bone formation: an analytical study
Journal of The Royal Society Interface, 2014
Bone cells (osteoblasts) produce a collagen-rich matrix called osteoid, which is mineralized extracellularly by nanosized calcium phosphate (CaP). Synthetically produced CaP nanoparticles (NPs) have great potential for clinical application. However few studies have compared the effect of CaP NPs with different properties, such as shape and aspect ratio, on the survival and behaviour of active bone-producing cells, such as primary human osteoblasts (HOBs). This study aimed to investigate the biocompatibility and ultrastructural effects of two differently shaped hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 ] nanoparticles (HA NPs), round- (aspect ratio 2.12, AR2) and rice-shaped (aspect ratio 3.79, AR4). The ultrastructural response and initial extracellular matrix (ECM) formation of HOBs to HA NPs were observed, as well as matrix vesicle release. A transmission electron microscopy (TEM)-based X-ray microanalytical technique was used to measure cytoplasmic ion levels, including calcium (Ca)...
Hydroxyapatite/Collagen Bone-Like Nanocomposite
Biological and Pharmaceutical Bulletin, 2013
Our group has succeeded to synthesize material with bone-like nanostructure and bone-like inorganic and organic composition via self-organization mechanism between them using simultaneous titration method under controlled pH and temperature. The hydroxyapatite/collagen (HAp/Col) bone-like nanocomposite completely incorporated into bone remodeling process to be substituted by new bone. Cells cultured on the HAp/Col revealed very interesting reactions. Osteoblast-like MG63 cells showed upregulation of alkaline phosphatase >3 times greater than MG63 cells cultured on tissue culture polystyrene (TCPS). MG63 cells 3-dimensionally cultured in a "HAp/Col sponge," a porous HAp/Col having sponge-like viscoelasticity, accumulated calcium phosphate nodules on extracellular matrices they secreted. Bone marrow cells co-cultured with osteoblasts on HAp/Col differentiated to osteoclasts without differentiation supplements. This phenomenon is not found in cells cultured on hydroxyapatite ceramics and TCPS, and rarely in cells cultured on dentin. These results suggest that HAp/Col is a good candidate for tissue engineering of bone as well as bone filler. In a clinical test as a bone filler, the HAp/Col sponge was significantly better than porous β-tricalcium phosphate. The HAp/Col sponge has been approved by the Japanese government and will be used as greatly needed bone filler in patients. In addition to the above, HAp/Col coating on titanium revealed higher osteoconductivity than HAp-coated titanium and bare titanium and improved direct bonding between titanium and newly formed bone. The HAp/Col coating may be used for metal devices requiring osseointegration.
In-situ hardening hydroxyapatite-based scaffold for bone repair
Journal of Materials Science: Materials in Medicine, 2006
Musculoskeletal conditions are becoming a major health concern because of an aging population and sports-and traffic-related injuries. While sintered hydroxyapatite implants require machining, calcium phosphate cement (CPC) bone repair material is moldable, self-hardens in situ, and has excellent osteoconductivity. In the present work, new approaches for developing strong and macroporous scaffolds of CPC were tested. Relationships were determined between scaffold porosity and strength, elastic modulus and fracture toughness. A biocompatible and biodegradable polymer (chitosan) and a water-soluble porogen (mannitol) were incorporated into CPC: Chitosan to make the material stronger, fastsetting and anti-washout; and mannitol to create macropores. Flexural strength, elastic modulus, and fracture toughness were measured as functions of mannitol mass fraction in CPC from 0% to 75%. After mannitol dissolution in a physiological solution, macropores were formed in CPC in the shapes of the original entrapped mannitol crystals, with diameters of 50 μm to 200 μm for cell infiltration and bone ingrowth. The resulting porosity in CPC ranged from 34.4% to 83.3% volume fraction. At 70.2% porosity, the hydroxyapatite scaffold possessed flexural strength (mean ± sd; n = 6) of (2.5 ± 0.2) MPa and elastic modulus of (0.71 ± 0.10) GPa. These values were within the range for sintered porous hydroxyapatite and cancellous bone. Predictive equations were established by re
Bone, 2012
We report the ultrastructure of regenerated bone surrounding two types of biomaterials: hydroxyapatitealginate composite and sintered hydroxyapatite. Critical defects in the calvaria of Wistar rats were filled with micrometer-sized spherical biomaterials and analyzed after 90 and 120 days of implantation by high-resolution transmission electron microscopy and Fourier transform infrared attenuated total reflectance microscopy, respectively. Infrared spectroscopy showed that hydroxyapatite of both biomaterials became more disordered after implantation in the rat calvaria, indicating that the biological environment induced modifications in biomaterials structure. We observed that the regenerated bone surrounding both biomaterials had a lamellar structure with type I collagen fibers alternating in adjacent lamella with angles of approximately 90°. In each lamella, plate-like apatite crystals were aligned in the c-axis direction, although a rotation around the c-axis could be present. Bone plate-like crystal dimensions were similar in regenerated bone around biomaterials and pre-existing bone in the rat calvaria. No epitaxial growth was observed around any of the biomaterials. A distinct mineralized layer was observed between new bone and hydroxyapatite-alginate biomaterial. This region presented a particular ultrastructure with crystallites smaller than those of the bulk of the biomaterial, and was possibly formed during the synthesis of alginatecontaining composite or in the biological environment after implantation. Round nanoparticles were observed in regions of newly formed bone. The findings of this work contribute to a better understanding of the role of hydroxyapatite based biomaterials in bone regeneration processes at the nanoscale.
Recent Advances in Hydroxyapatite-Based Biocomposites for Bone Tissue Regeneration in Orthopedics
International Journal of Molecular Sciences
Bone tissue is a nanocomposite consisting of an organic and inorganic matrix, in which the collagen component and the mineral phase are organized into complex and porous structures. Hydroxyapatite (HA) is the most used ceramic biomaterial since it mimics the mineral composition of the bone in vertebrates. However, this biomimetic material has poor mechanical properties, such as low tensile and compressive strength, which make it not suitable for bone tissue engineering (BTE). For this reason, HA is often used in combination with different polymers and crosslinkers in the form of composites to improve their mechanical properties and the overall performance of the implantable biomaterials developed for orthopedic applications. This review summarizes recent advances in HA-based biocomposites for bone regeneration, addressing the most widely employed inorganic matrices, the natural and synthetic polymers used as reinforcing components, and the crosslinkers added to improve the mechanica...
Characterization of a bovine collagen–hydroxyapatite composite scaffold for bone tissue engineering
Biomaterials, 2003
Different biomaterials have been used as scaffolds for bone tissue engineering. Here we characterize a biomaterial composed of sintered (1100°C) and powdered hydroxyapatite (HA) and type I collagen (Coll), both of bovine origin, designed for osteoconductive and osteoinductive scaffolds. Coll/HA proportions were 1/2.6 and 1/1 (wet weight), and particles sizes varied from 200 to 400 μm. Vv (volume density) and Sv (surface to volume density) for the HA particles in the composite ranged from 0.48±0.06 to 0.55±0.02 and 5.090±0.545 to 6.366±0.289 μm−1, respectively. Due to the relatively small changes in Vv and Sv, a macroporosity could be characterized for the biocomposite. X-ray diffraction and infrared spectroscopy showed that the sintered bone was composed essentially of HA with minimum additional groups such as surface calcium hydroxide, surface and crystal water, free carbon dioxide and possibly brushite. Mass spectrometry detected carbonates at A and B sites of HA, and weakly bound to the structure. Human osteoblasts adhered and spread on both the HA particle surface and the collagen fibers, which seemed to guide cells between adjacent particles. The biocomposite studied has several characteristics considered as ideal for its use as a scaffold for osteoconduction and osteoinduction.