Applications In Bone Surgery Research Articles

Exploring the potential of chitosan from royal shrimp waste for elaboration of chitosan/bioglass biocomposite: Characterization and “in vitro” bioactivity

Exploiting royal shrimp waste to produce value-added biocomposites offers environmental and therapeutic benefits. This study proposes biocomposites based on chitosan and bioglass, using shrimp waste as the chitosan source. Chitin extraction and chitosan preparation were characterized using various analytical techniques. The waste composition revealed 24 % chitin, convertible to chitosan, with shells containing 77.33-ppm calcium. (X-ray diffraction) XRD analysis showed crystallinity index of 54.71 % for chitin and 49.14 % for chitosan. Thermal analysis indicated degradation rates of 326 °C and 322 °C, respectively. The degree of deacetylation of chitosan was 97.08 % determined by proton nuclear magnetic resonance (1H-NMR) analysis, with an intrinsic viscosity of 498 mL.g−1 and molar mass of 101,720 g/mol, showing improved solubility in 0.3 % acetic acid. Royal chitosan (CHR) was combined with bioglass (BG) via freeze-drying to create a CHR/BG biocomposite for bone surgery applications. The bioactivity of the CHR/BG was tested in simulated body fluid (SBF), revealing a biologically active apatite layer on its surface. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis confirmed enhanced bioactivity of the CHR/BG compared to commercial chitosan. The CHR/BG biocomposite demonstrated excellent apatite formation, validated by Scanning Electron Microscopy (SEM), highlighting its potential in bone surgery.

Cu-doped bioactive glass with enhanced in vitro bioactivity and antibacterial properties

This work aimed to optimize, produce and characterize Cu-doped bioactive glasses which are antibacterial without the addition of antibiotics obtained via ion exchange in an aqueous solution. According to morphological, compositional and structural analyses, 0.001 M was selected as the most optimal concentration of the ion exchange solution. The doped glass was then compared to the undoped one to investigate the effect of Cu-doping on the glass surface composition and bioactivity. Cu-doping was found to enhance the bioactivity kinetics and the following hydroxyapatite formation, evidenced by X-ray diffraction, energy dispersive X-ray spectroscopy, and zeta potential measurements. Besides that, the zeta potential titration measurements confirmed that the Cu-doping did not alter the surface chemical stability of the glass both in the inflammatory and physiological pH range. Moreover, the leaching ability of Cu2+-ions, both in physiological and inflammatory-mimicking conditions, was measured, followed by an in-depth study of the antibacterial properties, using two protocols to distinguish between the antiadhesive, antibacterial, and antibiofilm effects. For both protocols, a reduction of metabolic activity and Colony-Forming Unit after 24 h against Staphylococcus aureus Multi-Drug resistance strain was evidenced. These results showed that Cu-doped glass could show potential as a bioactive and antibacterial surface for bone surgery applications.

Nanoscale Strontium-Substituted Hydroxyapatite Pastes and Gels for Bone Tissue Regeneration

Injectable nanoscale hydroxyapatite (nHA) systems are highly promising biomaterials to address clinical needs in bone tissue regeneration, due to their excellent biocompatibility, bioinspired nature, and ability to be delivered in a minimally invasive manner. Bulk strontium-substituted hydroxyapatite (SrHA) is reported to encourage bone tissue growth by stimulating bone deposition and reducing bone resorption, but there are no detailed reports describing the preparation of a systematic substitution up to 100% at the nanoscale. The aim of this work was therefore to fabricate systematic series (0–100 atomic% Sr) of SrHA pastes and gels using two different rapid-mixing methodological approaches, wet precipitation and sol-gel. The full range of nanoscale SrHA materials were successfully prepared using both methods, with a measured substitution very close to the calculated amounts. As anticipated, the SrHA samples showed increased radiopacity, a beneficial property to aid in vivo or clinical monitoring of the material in situ over time. For indirect methods, the greatest cell viabilities were observed for the 100% substituted SrHA paste and gel, while direct viability results were most likely influenced by material disaggregation in the tissue culture media. It was concluded that nanoscale SrHAs were superior biomaterials for applications in bone surgery, due to increased radiopacity and improved biocompatibility.

Is There a Role for Absorbable Metals in Surgery? A Systematic Review and Meta-Analysis of Mg/Mg Alloy Based Implants.

Magnesium (Mg) alloys have received attention in the literature as potential biomaterials for use as absorbable implants in oral and maxillofacial and orthopedic surgery applications. This study aimed to evaluate the available clinical studies related to patients who underwent bone fixation (patients), and received conventional fixation (intervention), in comparison to absorbable metals (comparison), in terms of follow-up and complications (outcomes). A systematic review and meta-analysis were performed in accordance with the PRISMA statement and PROSPERO (CRD42020188654), PICO question, ROBINS-I, and ROB scales. The relative risk (RR) of complications and failures were calculated considering a confidence interval (CI) of 95%. Eight studies (three randomized clinical trial (RCT), one retrospective studies, two case-control studies, and two prospective studies) involving 468 patients, including 230 Mg screws and 213 Titanium (Ti) screws, were analyzed. The meta-analysis did not show any significant differences when comparing the use of Mg and Ti screws for complications (p = 0.868). The estimated complication rate was 13.3% (95% CI: 8.3% to 20.6%) for the comparison group who received an absorbable Mg screw. The use of absorbable metals is feasible for clinical applications in bone surgery with equivalent outcomes to standard metal fixation devices.

P2000 - A high-nitrogen austenitic steel for application in bone surgery.

Optimal treatment of bone fractures with minimal complications requires implant alloys that combine high strength with high ductility. Today, TiAl6V4 titanium and 316L steel are the most applied alloys in bone surgery, whereas both share advantages and disadvantages. The nickel-free, high-nitrogen austenitic steel X13CrMnMoN18-14-3 (1.4452, brand name: P2000) exhibits high strength in combination with superior ductility. In order to compare suitable alloys for bone implants, we investigated titanium, 316L steel, CoCrMo and P2000 for their biocompatibility and hemocompatibility (according to DIN ISO 10993–5 and 10993–4), cell metabolism, mineralization of osteoblasts, electrochemical and mechanical properties. P2000 exhibited good biocompatibility of fibroblasts and osteoblasts without impairment in vitality or changing of cell morphology. Furthermore, investigation of the osteoblasts function by ALP activity and protein levels of the key transcription factor RUNX2 revealed 2x increased ALP activity and more than 4x increased RUNX2 protein levels for P2000 compared to titanium or 316 steel, respectively. Additionally, analyses of osteoblast biomineralization by Alizarin Red S staining exhibited more than 6x increased significant mineralization of osteoblasts grown on P2000 as compared to titanium. Further, P2000 showed no hemolytic effect and no significant influence on hemocompatibility. Nanoindentation hardness tests of Titanium and 316L specimens exposed an indentation hardness (HIT) of about 4 GPa, whereas CoCrMo and P2000 revealed HIT of 7.5 and 5.6 GPa, respectively. Moreover, an improved corrosion resistance of P2000 compared to 316L steel was observed. In summary, we could demonstrate that the nickel-free high-nitrogen steel P2000 appears to be a promising alternative candidate for applications in bone surgery. As to nearly all aspects like biocompatibility and hemocompatibility, cell metabolism, mineralization of osteoblasts and mechanical properties, P2000 was similar to or revealed advantages against titanium, 316L or CoCrMo.

Osteogenesis of Adipose-Derived and Bone Marrow Stem Cells with Polycaprolactone/Tricalcium Phosphate and Three-Dimensional Printing Technology in a Dog Model of Maxillary Bone Defects.

Bone graft material should possess sufficient porosity and permeability to allow integration with native tissue and vascular invasion, and must satisfy oxygen and nutrient transport demands. In this study, we have examined the use of three-dimensional (3D)-printed polycaprolactone/tricalcium phosphate (PCL/TCP) composite material in bone grafting, to estimate the scope of its potential application in bone surgery. Adipose-derived stem cells (ADSCs) and bone marrow stem cells (BMSCs) are known to enhance osteointegration. We hypothesized that a patient-specific 3D-printed solid scaffold could help preserve seeded ADSCs and BMSCs and enhance osteointegration. Diffuse osteogenic tissue formation was observed by micro-computed tomography with both stem cell types, and the ADSC group displayed similar osteogenesis compared to the BMSC group. In histological assessment, the scaffold pores showed abundant ossification in both groups. Reverse transcription polymerase chain reaction (RT-PCR) showed that the BMSC group had higher expression of genes associated with ossification, and this was confirmed by Western blot analysis. The ADSC- and BMSC-seeded 3D-printed PCL/TCP scaffolds displayed promising enhancement of osteogenesis in a dog model of maxillary bone defects.

The effects of different cross-linking conditions on collagen-based nanocomposite scaffolds—an in vitro evaluation using mesenchymal stem cells

Nanocomposite scaffolds which aimed to imitate a bone extracellular matrix were prepared for bone surgery applications. The scaffolds consisted of polylactide electrospun nano/sub-micron fibres, a natural collagen matrix supplemented with sodium hyaluronate and natural calcium phosphate nano-particles (bioapatite). The mechanical properties of the scaffolds were improved by means of three different cross-linking agents: N-(3-dimethylamino propyl)-N’-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide in an ethanol solution (EDC/NHS/EtOH), EDC/NHS in a phosphate buffer saline solution (EDC/NHS/PBS) and genipin. The effect of the various cross-linking conditions on the pore size, structure and mechanical properties of the scaffolds were subsequently studied. In addition, the mass loss, the swelling ratio and the pH of the scaffolds were determined following their immersion in a cell culture medium. Furthermore, the metabolic activity of human mesenchymal stem cells (hMSCs) cultivated in scaffold infusions for 2 and 7 days was assessed. Finally, studies were conducted of cell adhesion, proliferation and penetration into the scaffolds. With regard to the structural stability of the tested scaffolds, it was determined that EDC/NHS/PBS and genipin formed the most effectively cross-linked materials. Moreover, it was discovered that the genipin cross-linked scaffold also provided the best conditions for hMSC cultivation. In addition, the infusions from all the scaffolds were found to be non-cytotoxic. Thus, the genipin and EDC/NHS/PBS cross-linked scaffolds can be considered to be promising biomaterials for further in vivo testing and bone surgery applications.

Gelatin functionalized graphene oxide for mineralization of hydroxyapatite: biomimetic and in vitro evaluation

We report a facile modification of graphene oxide (GO) by gelatin to mimic charged proteins present in the extracellular matrix during bone formation. The bioinspired surface of GO-gelatin (GO-Gel) composite was used for biomimetic mineralization of hydroxyapatite (HA). A detailed structural and morphological characterization of the mineralized composite was performed. Additionally, MC3T3-E1 cells were cultured on the GO-Gel surfaces to observe various cellular activities and HA mineralization. Higher cellular activities such as cell adhesion, cell proliferation, and alkaline phosphatase activity (ALP) were observed on the GO-Gel surface compared with the GO or glass surface. The increase of ALP confirms that the proposed GO-Gel promotes the osteogenic differentiation of MC3T3-E1 cells. Moreover, the evidence of mineralization evaluated by scanning electron microscopy (SEM) and alizarin red staining (ARS) corroborate the idea that a native osteoid matrix is ultimately deposited. All these data suggest that the GO-Gel hybrids will have great potential as osteogenesis promoting scaffolds for successful application in bone surgery.

Osteoinduction and Antiosteoporotic Performance of Hybrid Biomaterial Chitosan-Bioactive Glass Graft: Effects on Bone Remodeling

Osteoinductive and antiosteroporotic phenomena could be created by using synthetic biomaterials for applications in bone surgery. In the present study, CH-based bioactive glass (BG-CH) with 17 wt% chitosan was elaborated by a freeze-drying process. BG-CH was implanted in the muscle and in the femoral condyles of ovariectomised rats. Grafted tissues were carefully removed for physico-chemical and histological analysis. Several physic-chemical techniques (XRD, FT-IR, MEB, ICP-OES and NMR) were employed to highlight the effects of chitosan on the glass matrix before and after implantation. The results of the study show that despite the non-additional osteogenic cells or agents, BG-CH is endowed with an osteoinductive property. After 8 weeks, 13C NMR spectra showed the characteristic signals of γ-carbons of the hydroxyproline (71 ppm) abundant in collagen. γ-carboxyglutamate (55 ppm), which occurs in several other bone proteins like osteocalcin, indicating the BGCH degradation and the dominance of the bone tissue formation. Moreover, this study showed a rise in Ca and P ion concentrations in the implanted microenvironment, leading to the formation/deposition of Ca-P phases. Trace elements such as Zn and Fe were detected in the newly-formed bone and involved in the bone healing. The study highlights the suitability and the extensive applications of BG-CH composites and the clinically useful therapy in regenerative medicine.

In vitro mineralization and bone osteogenesis in poly(ε‐caprolactone)/gelatin nanofibers

The implementation of bio-inspired strategies in developing scaffolds for the reconstruction of oral, craniofacial and bone skeletal tissues after injury or resection remains a challenge. Currently, advanced scaffolds comprising nanofibers endowed with biochemical/biophysical signaling capability offer great advantages in bone regeneration, because of their faithful mimesis of the characteristic size scales encountered in the fibrous network of the native extracellular matrix (ECM). In this study, we investigate the biological potential of nanofibers made of polycaprolactone and gelatin on guiding the regenerative mechanisms of bone. Contact angle measurements and environmental SEM investigations indicate a weak linkage of gelatin molecules to PCL chains, facilitating an efficient adhesion signal to cells up to 3 days of culture. In vitro studies performed on human mesenchymal stem cells (hMSC) until 3 weeks in culture medium with osteogenic supplementation, clearly showing the effectiveness of PCL/Gelatin electrospun scaffolds in promoting bone osteogenesis and mineralization. The increase of alkaline phosphatase activity (ALP) and gene expression of bone-related molecules (bone sialoprotein, osteopontin and osteocalcin), indicated by immunodetection and upregulation level of mRNA, confirm that proposed nanofibers promote the osteogenic differentiation of hMSC, preferentially in osteogenic medium. Moreover, the evidence of newly formed collagen fibers synthesis by SIRCOL and their mineralization evaluated by Alizarin Red staining and EDS mapping of the elements Ca, P and Mg corroborate the idea that native osteoid matrix is ultimately deposited. All these data suggest that PCL and gelatin electrospun nanofibers have great potential as osteogenesis promoting scaffolds for successful application in bone surgery.

Optimizing and evaluating the biocompatibility of fiber composites with calcium phosphate additives

Composite materials based on a polyamide fabric (aramid) and a polydymethylsiloxane (PDMS) matrix were designed for application in bone surgery. In order to increase the bioactivity, 2, 5, 10, 15, 20, and 25 vol.% of nano/micro hydroxyapatite (HA) and tricalcium phosphate (TCP) were added. We studied the effect of the additives on the biocompatibility of the composite. It appears that nano additives have a more favorable effect on mechanical properties than microparticles. 15 vol.% of nano hydroxyapatite additive is an optimum amount for final application of the composites as substitutes for bone tissue: in this case both the mechanical properties and the biological properties are optimized without distinct changes in the inner structure of the composite.

Biological performance of a new β‐TCP/PLLA composite material for applications in spine surgery: In vitro and in vivo studies

The objective of this research was to carry out an in vitro and in vivo study of the biological performance of PLLA/beta-TCP composite materials, to estimate the scope of their potential applications in bone surgery. Samples with increasing beta-TCP (0-60% w/w) contents were processed by injection molding. The in vitro study consisted of an evaluation of inflammatory potential by assaying the IL-1alpha secreted by monocytes, and then cell proliferation (counting) and phenotype expression (PAL and I collagen) in human osteogenous cells. The in vivo study was carried out using cylindrical implants of composite materials composed of composite materials containing 0 or 60% beta-TCP and pure beta-TCP, respectively. The implants were inserted in femoral sites in rabbits, using the Kathagen protocol. Each animal received a 60% implant, with either a 0 or a 100% implant in the contralateral femur, so that the materials could be compared with one another. Five animals were examined for each material and implantation period, giving a total of 30 animals. This study showed that adding increasing percentages of beta-TCP to a lactic acid polymer matrix stimulated the proliferation of human osteogenous cells and synthesis of the extracellular bone matrix in a dose-dependent manner. In vivo results indicate that, in comparison with pure PLA, tricalcium phosphate-containing composite materials had faster degradation kinetics, caused less inflammatory reaction, and promoted contact osteogenesis. The composite material containing 60% beta-TCP demonstrated a similar performance to pure tricalcium phosphate bone grafts in terms of osteogenesis, and is apparently compatible with the production of intra-osseous implants for situations representing high levels of mechanical strain.

Structure and bioactivity studies of new polysiloxane-derived materials for orthopedic applications

The aim of this work was to examine the structure of new calcium silicate bioactive ceramic implant material for bone surgery applications. The bioceramic material was obtained by thermal treatment of active fillers-containing organosilicon polymer precursor. Different ceramic active fillers, namely Ca(OH) 2, CaCO 3, Na 2HPO 4 and SiO 2 powders were used. The phase composition of ceramic samples obtained by thermal transformation of active fillers containing polysiloxane was investigated. Morphology and structure of ceramic phases were characterized by means of scanning electron microscopy (SEM) with EDS point analysis, FTIR spectroscopy and XRD analysis. It was found that thermal treatment of active fillers-containing organosilicon precursor lead to the formation of wollastonite-containing ceramic material. This ceramic material showed bioactivity in ‘in vitro’ conditions studied by immersing the samples in simulated body fluid (SBF). The surface of wollastonite-containing ceramic before and after immersion in SBF was analysed. It can be concluded that this kind of ceramic material may be useful as bone substitute. FTIR spectroscopy is an adequate device for the determination of such derived materials structure.

High-energy ion beam implantation of hydroxyapatite thin films grown on TiN and ZrO2 inter-layers by pulsed laser deposition

Current drawbacks in the hydroxyapatite (HA) thin film production for applications in bone surgery are their poor mechanical strength and limited adherence. This paper presents the ion beam implantation technique as an efficient method to improve the mechanical characteristics of HA films. Crystalline films of HA were grown by pulsed laser deposition, using a KrF* excimer laser (λ=248 nm, τ⩾20 ns). The depositions were performed from pure HA targets on Ti–5Al–2.5Fe alloys coated with TiN or ZrO2 buffer layers. Samples were then implanted with Ar+ ions of high-energy (1.5 MeV) at a dose of 1016 cm−2. The as-deposited and implanted films were characterized by light microscopy and energy dispersive X-ray spectrometry. The mechanical properties of films were studied by nanoindentation and nano-scratch techniques using a Berkovich indenter tip. Films become harder and exhibit a higher Young modulus after implantation. The best values (5 GPa hardness and 130 GPa Young modulus, respectively) were obtained for the implanted films grown on TiN. An influence of the buffer layer nature on the mechanical behavior of films was observed. Films grown on ZrO2 are brittle and crack at moderate load (∼12 mN) during scratch while these ones deposited on TiN successfully withstand loading. Residual stresses occur into the HA/ZrO2 structure during processing and ion bombardment.

Influence of surfactant molecules as air-entraining agent for bone cement macroporosity.

Calcium phosphate bone cements (CPBCs) represent a potential synthetic alternative to bone-graft materials in bone surgery applications. CPBCs are biocompatible, bioresorbable, and slowly are replaced by new bone in vivo. However, CPBCs do not develop a macroporosity during setting that would allow fast bone ingrowth and good osteointegration of the implant. For this reason, recent research has approached the problem of inducing macroporosity inside the bone cement without influencing its normal setting. In this study, a new method for obtaining injectable macroporous CPBCs is proposed. It is based on the use of sodium dodecyl sulphate (SDS) as an air-entraining agent. The results have shown that the liquid-to-powder ratio and the SDS concentration, as well as the diameter and the interconnectivity of the macropores, can control the micro- and macroporosity. This new technology can be used to develop and optimize new commercial products for osteoporotic bone filling applications. Furthermore, the presented method also can be used at low temperatures before an operation to produce preformed implants to fit the particular needs of a patient.

Nonresorbable polymers in bone surgery

Sufficient strength and stiffness, biocompatibility and long-term stability are important criteria that polymers have to fulfill for successful implant applications in bone surgery. An additional requirement is sterilization without degradation of the polymer properties. Ultra-high molecular weight polyethylene is used as a carrier material in joint replacement components because of good wear and damping properties. Nevertheless, reduction of wear is still a major challenge in polyethylene research as wear particles are responsible for early loosening of prosthetic devices. Acrylic bone cement is used for the fixation of artificial joints, providing an immediate and strong fixation of the implant. Possible problems with this bone cement are the residual (toxic) monomers and the high curing temperature that may cause thermal bone necrosis. Polyacetal resins are implantable high performance polymers. Due to their high chemical and mechanical resistance, they are used in joint replacement components and other long-term implants. Polyetheretherke- tone is a new and even more stable high performance polymer. Due to its stability at sterilization temperatures and under irradiation, PEEK is intended to replace POM in future. PEEK is available in a “medical grade” quality suitable for long-term implantation.

Biomedical polymers from chiral lactides and functional lactones: Properties and applications

AbstractConfiguration‐respecting ring opening polymerization of ester‐containing chiral cyclic monomers derived from metabolic compounds as lactic, glycolic and malic acids has a two‐fold interest. First, it can lead to stereoregular polymers and copolymers whose physical, mechanical and biological properties can be adjusted through structural parameters. Secondly, resulting polymers can be degraded to the metabolic precursors of repeating units. Prerequisites which have to be taken into account for the selection and the tailor‐making of bioresorbable polymers for applications in bone surgery and drug delivery are presented. Emphasis is made on structure‐property relationships.

Stereoregular bioresorbable polyesters for orthopaedic surgery

The feasability of using poly(α-hydroxy-acid)s (poly-(glycolic acid), poly(L-lactic acid), L and D-lactic acid stereocopolymers and copolymers of glycolic and L- and D-lactic acids) for processing bioresorbable bone plates, screws, nails etc..., is questioned in regard to the requirements for effective applications and to the data reported in the open literature. Experiments carried out on home-made samples confirm the biocompatibility of these polyesters and the fast resorption of the amorphous compounds. In contrast, our results concerning crystalline poly(L-lactic acid) disagree with those of the literature. The discrepancies might result from differences in the basic material, differences in crystallinity and/or degradation of macromolecules which has been shown to occur sometimes during the elaboration of ready-for-implantation samples. Indeed, quasi-biostable bone plates based on isotactic poly(L-lactic acid) have been obtained according to an elaboration process which preserves the integrity of the synthesized macromolecules. The effects of enantiomeric purity and of implantation time on the tensile strength are reported for a series of welldefined stereocopolymers. Current studies show that highly isotactic poly(lactic acid)s (L/L+D > 92%) are polymers of particular interest for effective applications in bone surgery, especially for the construction of completely resorbable composite devices whose reinforcement consists of poly(glycolic acid) fibers.