Materials For Tissue Repair Research Articles

Comparative proteomics analysis of human stem cells from dental gingival and periodontal ligament.

Dental stem cells isolated from oral tissues have been shown to provide with high proliferation ability and multilineage differentiation potential. Gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs), kinds of dental stem cells, can be used as substitutes for tissue repair materials because of their similar regenerative functions. In this study, we aim to explore the similarities and differences between the protein profiles of GMSCs and PDLSCs through quantitative proteomics. A total of 2821 proteins were identified and retrieved, of which 271 were upregulated and 57 were downregulated in GMSCs compared to PDLSCs. Gene Ontology (GO) analysis demonstrated that the 328 differentially abundant proteins (DAPs) were involved in the regulation of gene expression, metabolism, and signal transduction in biological process, mainly distributed in organelles related to vesicle transport, and involved in the molecular function of binding protein. And Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the DAPs were committed to regulating the synthesis of proteasome and spliceosome. Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that ARPC1B, PDAP1, and SEC61B can be used as special markers to distinguish GMSCs from PDLSCs. This research contributes to explaining the molecular mechanism and promoting the clinical application of tissue regeneration of GMSCs and PDLSCs.

Inorganic Polymeric Materials for Injured Tissue Repair: Biocatalytic Formation and Exploitation.

Two biocatalytically produced inorganic biomaterials show great potential for use in regenerative medicine but also other medical applications: bio-silica and bio-polyphosphate (bio-polyP or polyP). Biosilica is synthesized by a group of enzymes called silicateins, which mediate the formation of amorphous hydrated silica from monomeric precursors. The polymeric silicic acid formed by these enzymes, which have been cloned from various siliceous sponge species, then undergoes a maturation process to form a solid biosilica material. The second biomaterial, polyP, has the extraordinary property that it not only has morphogenetic activity similar to biosilica, i.e., can induce cell differentiation through specific gene expression, but also provides metabolic energy through enzymatic cleavage of its high-energy phosphoanhydride bonds. This reaction is catalyzed by alkaline phosphatase, a ubiquitous enzyme that, in combination with adenylate kinase, forms adenosine triphosphate (ATP) from polyP. This article attempts to highlight the biomedical importance of the inorganic polymeric materials biosilica and polyP as well as the enzymes silicatein and alkaline phosphatase, which are involved in their metabolism or mediate their biological activity.

Icariin-releasing 3D printed scaffold for bone regeneration

The polycaprolactone (PCL) and nano-hydroxyapatite (nHAP) composite is an attractive material for bone scaffolds with excellent mechanical properties and osteoinductivity . It also exhibited good biocompatibility as well as controllable biodegradability . We have recently developed a PCL and nHAP composite scaffold , which is embedded with poly (lactic-co-glycolic acid) (PLGA) microspheres ( μs ). It achieved controlled delivery of bioactive factors . In this study, Icariin (ICA) encapsulated with PLGA μs was embedded in 3D printed PCL/nHAP scaffolds to facilitate in situ bone regeneration. The scaffold exhibited excellent mechanical performance owing to the nHAP. The PCL/nHAP scaffold showed sustainable release of ICA as the PCL degraded. The PCL degradation produced cracks on the surface of the scaffold, and then the PLGA μs was exposed to phosphate buffer solution. The released ICA promoted the osteogenic differentiation of MC3T3-E1. Consistently, in vivo studies showed that the composite scaffolds releasing ICA promoted the healing of calvaria bone. In conclusion, PCL/PLGA μs /nHAP composite scaffold by 3D printing may serve as an efficient material for bone tissue repair and regeneration. • A PCL/nHAP composite scaffold embedded with ICA-loaded PLGAµs was fabricated by 3D printing technology. • The nHAP particles enhanced the mechanical property and surface roughness of the scaffolds. • The composite scaffold exhibited sustained release of ICA as the degradation creating cracks of PCL.

2D Materials for Cardiac Tissue Repair and Regeneration.

Cardiovascular diseases (CVDs) have a massive impact on human health. Due to the limited regeneration capacity of adult heart tissue, CVDs are the leading cause of death and disability worldwide. Even though there are surgical and pharmacological treatments for CVDs, regenerative strategies are the most promising approaches and have the potential to benefit millions of people. As in any other tissue engineering approach, the repair and regeneration of damaged cardiac tissues generally involve scaffolds made up of biodegradable and biocompatible materials, cellular components such as stem cells, and growth factors. This review provides an overview of biomaterial-based tissue engineering approaches for CVDs with a specific focus on the potential of 2D materials. It is essential to consider both physicochemical and immunomodulatory properties for evaluating the applicability of 2D materials in cardiac tissue repair and regeneration. As new members of the 2D materials will be explored, they will quickly become part of cardiac tissue engineering technologies.

Anticorrosive and antibacterial smart integrated strategy for biomedical magnesium

Biomedical magnesium is an ideal material for hard tissue repair and replacement. However, its rapid degradation and infection after implantation significantly hindersclinical applications. To overcome these two critical drawbacks, we describe an integrated strategybased on the changes in pH and Mg2+ triggered by magnesiumdegradation. This system can simultaneously offer anticorrosion and antibacterial activity. First, nanoengineered peptide-grafted hyperbranched polymers (NPGHPs) with excellent antibacterial activity were introduced to sodium alginate (SA) to construct a sensitive NPGHPs/SA hydrogel. The swelling degree, responsiveness, and antibacterial activity were then investigated,indicating that the system can perform dual stimulation of pH and Mg2+ with controllable antimicrobial properties. Furthermore, an intelligent platform was constructed by coating hydrogels on magnesium with polydopamine as the transition layer. The alkaline environment generated by the corrosion of magnesium reduces the swelling degree of the coatingso that the liquid is unfavorable for contacting the substrate, thus exhibiting superior corrosion resistance. Antibacterial testing shows that the material can effectively fight against bacteria, while hemolytic and cytotoxicity testing suggest that it is highly biocompatible. Thus, this work realizes the smart integration of anticorrosion and antibacterial properties of biomedical magnesium, thereby providing broader prospects for the use of magnesium.

DEVELOPMENTAL STATUS AND PERSPECTIVES FOR TISSUE ENGINEERING IN UROLOGY

Tissue engineering technology and tissue cell-based stem cell research have made great strides in treating tissue and organ damage, correcting tissue and organ dysfunction, and reducing surgical complications. In the past, traditional methods have used biological substitutes for tissue repair materials, while tissue engineering technology has focused on merging sperm cells with biological materials to form biological tissues with the same structure and function as their own tissues. The advantage is that tissue engineering technology can overcome donors. Material procurement restrictions can effectively reduce complications. The aim of studying tissue engineering technology is to find sperm cells and suitable biological materials to replace the original biological functions of tissues and to establish a suitable in vivo microenvironment. This article mainly describes the current developments of tissue engineering in various fields of urology and discusses the future trends of tissue engineering technology in the treatment of complex diseases of the urinary system. The results of the research in this article indicate that while the current clinical studies are relatively few, the good results from existing animal model studies indicate good prospects of tissue engineering technology for the treatment of various urinary tract diseases in the future. Key words: Tissue engineering, kidney, ureter, bladder, urethra

Novel Hydroxyapatite Whiskers Modified by Silver Ion and Nano Zinc Oxide Used for Bone Defect Repairment

The hydroxyapatite (HA) is widely used as bone tissue repair material. The improvement of the antibacterial performance is an aroused general interest. In the present study, the silver ion and nano-zinc oxide modified hydroxyapatite whiskers (HAw) were successfully prepared. The microstructure and the composition of the modified HAw were analyzed by Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffractometer (XRD). SEM analysis showed that the length of the whiskers was 70–190 μm, and the aspect ratio was 10–60. With the increase of Ag+ content, the length and aspect ratio of the whiskers gradually decreased and incomplete spherical hydroxyapatite appeared. FEEM analysis showed that nano-zinc oxide particles on ZnO/3Ag-HAw surface are evenly distributed; the average particle size is less than 30 nm. XRD analysis showed that after sol-gel and calcination treatment, the nano-zinc oxide phase appeared in the diffraction pattern of ZnO/Ag-HAw. TEM analysis showed that the interplanar spacing of 5Ag-HAw increased slightly. The CCK-8 and cells co-culture assays were used to assess the proliferation and differentiation of MC3T3-E1 cells, respectively. The antibacterial abilities of the modified HAw against E. coli (ATCC25922) and S. aureus (ATCC6538) were investigated. The cell cytotoxicity test showed that the cytotoxicity level was 0, and there was no cytotoxicity. Cell adhesion experiments showed that ZnO/3Ag-HAw has good cell compatibility and biological activity. The modified hawthorn has a bacteriostatic rate of more than 90% and has good bacteriostatic activity.

A biomimetic triple-layered biocomposite with effective multifunction for dura repair

Dura mater defect and subsequent cerebrospinal fluid (CSF) leakage usually appear in trauma or neurosurgical procedures and are followed by a series of serious complications and even death. The use of a qualified dura mater substitute with multifunction of leakage blockade, adhesion prevention, and dura reconstruction is one of the promising treatment methods. However, even though some products have been used in the clinic, none of the substitutes achieved the required multifunction. In this study, we aimed to design and fabricate a dura repair composite with the ideal multifunction. By biomimicking the structure and component of natural dura, we applied poly(L-lactic acid) (PLLA), chitosan (CS), gelatin, and acellular small intestinal submucosa (SIS) powders to successfully prepare a triple-layered composite. Then, a series of specific devices and techniques were developed to investigate the performance. The results revealed that satisfactory structural stability could be realized under good synergistic interactions among the components. In addition, all the findings suggested that the bionic triple-layered composite showed satisfactory multifunction of leakage blockade, adhesion prevention, antibacterial property, and dura reconstruction potential, and thus, it might be a promising candidate for dura repair. Statement of significanceDeveloping qualified dura mater substitutes with multifunction of leakage blockade, adhesion prevention, and dura reconstruction is crucial for treating dura mater defect and subsequent cerebrospinal fluid (CSF) leakage that appear in trauma or neurosurgical procedures. In this study, we designed and fabricated a triple-layered dura repair biocomposite with satisfactory structural stability and desired multifunction based on biomimicking of the structure and component of natural dura. Moreover, a series of specific devices and techniques were developed to investigate the relevant performance. Overall, the developed hydrogel electrospinning system exhibited excellent advantages in achieving multifunction and could be applied widely in the future to achieve multifunctional tissue repair materials.

Bioactive glass-ceramic synthesis using nano and normal silica: a comparative study

Bioactive glass-ceramics are very promising materials for soft and hard tissue repair due to their high biocompatibility and bioactivity. The bioactive glass-ceramics (NSGC) containing (38-X)normal-SiO2-28CaO-18Al2O3-12CaF2-4P2O5-Xnano-SiO2 (mol%) (where X = 0, 19, and 38) system were synthesized using melt-quench method. The thermal behaviors were assessed by differential thermal analysis (DTA). The glass transition temperature (Tg) was high in the case of a mixture of 19 mol% normal silica and 19 mol% nano-silica. However, it was less with 38 mol%, either normal silica-containing or nano-silica-containing samples. As the quantity of nano-silica increases, the crystallization peak temperature (Tp) was increased. The X-ray diffractometer (XRD) result showed that the fluorapatite (FA) (Ca5(PO4)3F), mullite (M) (3Al2O3.2SiO2), and wollastonite (W) (CaSiO3) had the main crystalline phases for all the three batches. The crystals were needle and irregular shaped in all sintered specimens, as shown in a scanning electron microscope (SEM). They also showed the indications of surface cracks in case of high sintering temperature. Energy-dispersive X-ray spectroscopy (EDX) analysis showed the specimen’s elemental composition before and after the immersion in synthetic body fluid (SBF) solution. Fourier transform infrared (FTIR) spectra showed the characteristic peaks for Si–O–Si, Si–O–Ca, C–O stretching, O–H bending vibration, carbonate, and phosphate groups. The transmission electron microscope (TEM) images confirmed that the nanoparticles (2.58–8.15 nm) were present in the prepared glass-ceramics. The hydroxycarbonate apatite (HCA) layer was developed after 28 days of immersing in the modified SBF. The addition of nano-SiO2 in the specimens showed an increase in Vickers hardness, density, and acid-base resistivity.

Microvesicles from Schwann-Like Cells as a New Biomaterial Promote Axonal Growth.

Schwann cells promote axonal regeneration following peripheral nerve injury. However, in terms of clinical treatment, the therapeutic effects of Schwann cells are limited by their source. The transmission of microvesicles from neuroglia cells to axons is a novel communication mechanism in axon regeneration.To evaluate the effect of microvesicles released from Schwann-like cells on axonal regeneration, neural stem cells derived from human embryonic stem cells differentiated into Schwann-like cells, which presented a typical morphology and characteristics similar to those of schwann cells. The glial markers like MBP, P0, P75NTR, PMP-22, GFAP, HNK-1 and S100 were upregulated, whereas the neural stem markers like NESTIN, SOX1 and SOX2 were significantly downregulated in schwann-like cells. Microvesicles enhanced axonal growth in dorsal root ganglia neurons and regulated GAP43 expression in neuron-like cells (N2A and PC12) through the PTEN/PI3 K/Akt signaling pathway. A 5 mm section of sciatic nerve was transected in Sprague-Dawley rats. With microvesicles transplantation, regenerative nerves were evaluated after 6 weeks. Microvesicles increased sciatic function index scores, delayed gastrocnemius muscle atrophy and elevated βIII-tubulin-labeled axons in vivo. Schwann-like cells serve as a convenient source and promote axonal growth by secreting microvesicles, which may potentially be used as bioengineering materials for nerve tissue repair.

Bioactive Materials for Soft Tissue Repair.

Over the past decades, age-related pathologies have increased abreast the aging population worldwide. The increased age of the population indicates that new tools, such as biomaterials/scaffolds for damaged tissues, which display high efficiency, effectively and in a limited period of time, for the regeneration of the body's tissue are needed. Indeed, scaffolds can be used as templates for three-dimensional tissue growth in order to promote the tissue healing stimulating the body's own regenerative mechanisms. In tissue engineering, several types of biomaterials are employed, such as bioceramics including calcium phosphates, bioactive glasses, and glass–ceramics. These scaffolds seem to have a high potential as biomaterials in regenerative medicine. In addition, in conjunction with other materials, such as polymers, ceramic scaffolds may be used to manufacture composite scaffolds characterized by high biocompatibility, mechanical efficiency and load-bearing capabilities that render these biomaterials suitable for regenerative medicine applications. Usually, bioceramics have been used to repair hard tissues, such as bone and dental defects. More recently, in the field of soft tissue engineering, this form of scaffold has also shown promising applications. Indeed, soft tissues are continuously exposed to damages, such as burns or mechanical traumas, tumors and degenerative pathology, and, thereby, thousands of people need remedial interventions such as biomaterials-based therapies. It is known that scaffolds can affect the ability to bind, proliferate and differentiate cells similar to those of autologous tissues. Therefore, it is important to investigate the interaction between bioceramics and somatic/stem cells derived from soft tissues in order to promote tissue healing. Biomimetic scaffolds are frequently employed as drug-delivery system using several therapeutic molecules to increase their biological performance, leading to ultimate products with innovative functionalities. This review provides an overview of essential requirements for soft tissue engineering biomaterials. Data on recent progresses of porous bioceramics and composites for tissue repair are also presented.

Injectable DMEM-induced phenylboronic acid-modified hyaluronic acid self-crosslinking hydrogel for potential applications in tissue repair

Most of traditional injectable hydrogels based on light curing or enzyme crosslinking are difficult to control the crosslinking time accurately and lack tissue adhesion, which leads to difficult clinical application and poor tissue repair effect. In this study, a novel injectable DMEM (Dulbecco’s Modified Eagle’s Medium)-induced phenylboronic acid-modified hyaluronic acid self-crosslinking hydrogel was designed and prepared by combining the phenylboronic acid and a diol on hyaluronic acid as the main network, in which dynamically reversible phenylboronic acid esters imparted good self-healing properties and tissue adhesion properties to the hydrogels. Cell medium that induced the formation of the hydrogel could simulate the pH of the physiological environment and provide uniform nutrients for the encapsulated cells. In addition, in vitro cell experiments indicated that the DMEM-induced phenylboronic acid-modified hyaluronic acid self-crosslinking hydrogel was capable of supporting cell loading and proliferation, thus being a promising candidate for tissue repair materials.

Biomineralization of Collagen-Based Materials for Hard Tissue Repair.

Hydroxyapatite (HA) reinforced collagen fibrils serve as the basic building blocks of natural bone and dentin. Mineralization of collagen fibrils play an essential role in ensuring the structural and mechanical functionalities of hard tissues such as bone and dentin. Biomineralization of collagen can be divided into intrafibrillar and extrafibrillar mineralization in terms of HA distribution relative to collagen fibrils. Intrafibrillar mineralization is termed when HA minerals are incorporated within the gap zone of collagen fibrils, while extrafibrillar mineralization refers to the minerals that are formed on the surface of collagen fibrils. However, the mechanisms resulting in these two types of mineralization still remain debatable. In this review, the evolution of both classical and non-classical biomineralization theories is summarized. Different intrafibrillar mineralization mechanisms, including polymer induced liquid precursor (PILP), capillary action, electrostatic attraction, size exclusion, Gibbs-Donnan equilibrium, and interfacial energy guided theories, are discussed. Exemplary strategies to induce biomimetic intrafibrillar mineralization using non-collagenous proteins (NCPs), polymer analogs, small molecules, and fluidic shear stress are discussed, and recent applications of mineralized collagen fibers for bone regeneration and dentin repair are included. Finally, conclusions are drawn on these proposed mechanisms, and the future trend of collagen-based materials for bone regeneration and tooth repair is speculated.

Comparative Study on 3D Printed Ti6Al4V Scaffolds with Surface Modifications Using Hydrothermal Treatment and Microarc Oxidation to Enhance Osteogenic Activity.

Titanium (Ti) and its alloys have been widely used in clinics as preferred materials for bone tissue repair and replacement. However, the lack of biological activity of Ti limits its clinical applications. Surface modification of Ti with bioactive elements has always been a research hotspot. In this study, to promote the osseointegration of Ti6Al4V (Ti64) implants, calcium (Ca), oxygen (O), and phosphorus (P) codoped multifunctional micro–nanohybrid coatings were prepared on a three-dimensional (3D) printed porous Ti64 surface by microarc oxidation (MAO) and a hydrothermal method (HT). The surface morphologies, chemical compositions, and surface/cell interactions of the obtained coatings were studied. In vitro experiments indicated that all hybrid coating-modified Ti64 implants could enhance protein adsorption and MC3T3 osteoblasts’ activity, adhesion, and differentiation ability. In vivo experiments showed that the hybrid coating promoted early osseointegration. By comparison, microarc oxidation-treated Ti64 (M-Ti) has the best biological activity and the strongest ability of osseointegration. It provides important theoretical significance and potential application prospects for improving the biological activity of Ti implants.

Evaluation of bioactive glass scaffolds incorporating SrO or ZnO for bone repair: In vitro bioactivity and antibacterial activity.

A series of bioactive glass scaffolds doped with SrO or ZnO (0, 5, and 10 mol%) were synthesized by the foam replica and melting method. The thermodynamic evolution, phase composition, microstructure, ion release, in vitro bioactivity, and oxygen density of the scaffolds were characterized. The proliferation of murine long bone osteocyte Y4 cells was studied by cell culture. The survival rate of the BGs evaluated the antibacterial activity and Escherichia coli strains in co-culture. The results indicated that the process window decreases with the increase of dopants. All the samples have a pore structure size of 200-400 μm. When the scaffolds were immersed in simulated body fluid for 28 days, hydroxyapatite formation was not affected, but the degradation process was retarded. The glass network packing and ionic radii variations of the substitution ions control surface degradation, glass dissolution, and ion release. MTT results revealed that 5Sr-BG had a significant effect on promoting cell proliferation and none of the BGs were cytotoxicity. Sr-BGs and Zn-BGs exhibited significantly inhibited growth against E. coli bacterial strains. Generally, these results showed the 5Sr-BG scaffold with high vitro bioactivity, cell proliferation, and antibacterial property is an important candidate material for bone tissue regeneration and repair.

Combination of collagen scaffold with doxycycline for the treatment of cartilage and subchondral bone defects

The repair of cartilage and bone tissue post arthritis or injury in the knee joint is a challenge to the orthopedics. Both doxycycline and collagen scaffolds had been shown with positive influences on the repair of the tissue. Doxycycline inhibits catabolism related enzymes. Collagens provide tissue repair materials. In this study, the influence of doxycycline and jellyfish collagen (JFC) scaffold to the cells in vitro and tissue repair in vivo was studied. Doxycycline was found with a broad inhibition of the matrix metallopeptidases. It also had an enhancement to the progenitor chondrocytes but suppressed the maturation of chondrocytes. JFC (major type II collagen) was seen had improved both type I and type II collagen production during chondrogenesis of mesenchymal stem cells in vitro. Both doxycycline and JFC enhanced the bone formation and had synergistic effects in a late-stage during the bone repair process. However, the cartilage repair was found with no significant influence after the implantations. Overall, the control of metabolism by doxycycline and providing stimulation to collagen production by the implantation of JFC only contribute to bone growth but had little influence on cartilage repair. This indicates the growth of cartilage tissue needs more delicate regulation. The subchondral bone repair, even with some chondrocytes and proteoglycan deposition in the extracellular matrix could not convert to a repair with mature hyaluronic cartilage tissue.

Ag and peptide co-decorate polyetheretherketone to enhance antibacterial property and osteogenic differentiation

Polyetheretherketone (PEEK) has been well concerned as a promising material for hard tissue repair because of its outstanding mechanical behavior and superior biocompatibility. However, its clinical application is limited by its biological inertness and the susceptibility to bacterial infection during implantation. To improve the original shortcomings, self-polymerized dopamine (PDA) was used to enrich silver ions on the PEEK surface. Moreover, a layer of carboxymethyl chitosan (CMC) film was formed on the PEEK surface by the spin-coating method, aiming to control the release of silver ions on the surface. At the same time, bone forming peptide (BFP) was modified onto the PEEK surface by 1-(3-dimethylaminopropyl)-3-ethylcarbonimide hydrochloride (EDC) / N-hydroxy succinimide (NHS). The characterization results showed that PEEK-Ag-CMC-BFP could be obtained successfully. The inhibition zone and bacterial kinetic curve showed a favorable inhibitory effect of the sliver-modified PEEK on gram-negative and gram-positive bacteria. In vitro experiments exhibited that PEEK-Ag-CMC-BFP had a better biological activity than that of PEEK, which could promote cell proliferation and osteogenic differentiation. It is expected that this dual-function material with antibacterial and bone-promoting properties has a vast potential applied in the field of hard tissue repair.

A thermostability perspective on enhancing physicochemical and cytological characteristics of octacalcium phosphate by doping iron and strontium

Investigation of thermostability will lead the groundbreaking of unraveling the mechanism of influence of ion-doping on the properties of calcium phosphates. In this work, octacalcium phosphate (OCP), a metastable precursor of biological apatite, was used as a stability model for doping ions (Fe3+ and Sr2+) with different ionic charges and radii. After treated under hot air at different temperatures (110–200 °C), the phase, morphology, structure, physicochemical properties, protein affinity, ions release, and cytological responses of the ion-doped OCPs were investigated comparatively. The results showed that the collapse of OCP crystals gradually occurred, accompanying with the dehydration of hydrated layers and the disintegration of plate-like crystals as the temperature increased. The collapsed crystals still retained the typical properties of OCP and the potential of conversion into hydroxyapatite. Compared to the undoped OCP, Fe-OCP, and Sr-OCP had lower and higher thermostability respectively, leading to different material surface properties and ions release. The adjusted thermostability of Fe-OCP and Sr-OCP significantly enhanced the adsorption of proteins (BSA and LSZ) and the cytological behavior (adhesion, spreading, proliferation, and osteogenic differentiation) of bone marrow mesenchymal stem cells to a varying extent under the synergistic effects of corresponding surface characteristics and early active ions release. This work paves the way for understanding the modification mechanism of calcium phosphates utilizing ion doping strategy and developing bioactive OCP-based materials for tissue repair.

Microstructure and biological activity of silicon‐doped composite coatings fabricated by micro‐arc oxidation on magnesium alloy

Among biomaterials, the mechanical properties of magnesium and its alloys are closest to those of human bone tissue, making these ideal materials for bone tissue repair and replacement. In order to further improve the biocompatibility and biological activity of the magnesium alloy AZ91D, micro‐arc oxidation with a constant‐current power supply mode was employed in this study in a silicate electrolyte solution. The resultant coating surface had a porous structure, and silicon was evenly distributed in it. Further, the results of in vitro experimental studies showed that the silicon‐doped magnesium coating on the surface of the magnesium alloys has no obvious cytotoxicity, and it can induce the proliferation of osteoblasts and promote actin stretching. In addition, it has good biological activity and biocompatibility. Thus, the novel method developed in this study improves the potential for clinical applications of magnesium alloys.

Chitosan-Based Biomimetically Mineralized Composite Materials in Human Hard Tissue Repair.

Chitosan is a natural, biodegradable cationic polysaccharide, which has a similar chemical structure and similar biological behaviors to the components of the extracellular matrix in the biomineralization process of teeth or bone. Its excellent biocompatibility, biodegradability, and polyelectrolyte action make it a suitable organic template, which, combined with biomimetic mineralization technology, can be used to develop organic-inorganic composite materials for hard tissue repair. In recent years, various chitosan-based biomimetic organic-inorganic composite materials have been applied in the field of bone tissue engineering and enamel or dentin biomimetic repair in different forms (hydrogels, fibers, porous scaffolds, microspheres, etc.), and the inorganic components of the composites are usually biogenic minerals, such as hydroxyapatite, other calcium phosphate phases, or silica. These composites have good mechanical properties, biocompatibility, bioactivity, osteogenic potential, and other biological properties and are thus considered as promising novel materials for repairing the defects of hard tissue. This review is mainly focused on the properties and preparations of biomimetically mineralized composite materials using chitosan as an organic template, and the current application of various chitosan-based biomimetically mineralized composite materials in bone tissue engineering and dental hard tissue repair is summarized.