Evaluation of the cytocompatibility hemocompatibility in vivo bone tissue regenerating capability of different PCL blends

3D-printed implants loaded with acriflavine for glioblastoma treatment

Drug delivery routes play an essential role in determining the efficacy and safety of medications. This study focused on the development and optimization of 3D-printed reservoir type implants as a combinational therapy drug delivery system for Glioblastoma Multiforme (GBM) post-surgery, possessing also antibacterial properties. In this study, we used a multimodal agent, Acriflavine (ACF) as an alternative drug to treat GBM. To date, ACF is used only as an antiseptic agent, although it has been shown to possess strong anticancer activities. ACF and a low molecular weight PCL were loaded into 3D-printed reservoir-type implants for sustained drug delivery. The study demonstrated that ACF implants exhibited sustained drug release kinetics, with faster release during the initial 30 days, followed by a gradual decrease over 90 days. This controlled release profile enhances the effectiveness of ACF delivery to tumour targets while minimizing side effects associated with systemic administration. In vitro experiments confirmed the inhibitory activity of ACF against GBM cells compared to non-tumour cells. The study also highlighted the bacteriostatic effects of ACF, making the implants potentially useful for post-surgery infection management, particularly against S. aureus, a common bacterial infection associated with brain surgery. The long-term drug-release capabilities of the implants make them attractive candidates for both tumour inhibition and antibacterial treatment. The study suggests that the developed ACF delivery systems have the potential for future clinical studies. Their ability to provide increased drug efficacy without systemic toxicity makes them promising candidates for cancer therapy and post-surgery infection management.

Enhancing osteoblast proliferation and bone regeneration by poly (amino acid)/selenium-doped hydroxyapatite

Among various biomaterials employed for bone repair, composites with good biocompatibility and osteogenic ability had received increasing attention from biomedical applications. In this study, we doped selenium (Se) into hydroxyapatite (Se-HA) by the precipitation method, and prepared different amounts of Se-HA-loaded poly (amino acid)/Se-HA (PAA/Se-HA) composites (0, 10 wt%, 20 wt%, 30 wt%) byin-situmelting polycondensation. The physical and chemical properties of PAA/Se-HA composites were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and their mechanical properties. XRD and FT-IR results showed that PAA/Se-HA composites contained characteristic peaks of PAA and Se-HA with amide linkage and HA structures. DSC and TGA results specified the PAA/Se-HA30 composite crystallization, melting, and maximum weight loss temperatures at 203.33 °C, 162.54 °C, and 468.92 °C, respectively, which implied good thermal stability. SEM results showed that Se-HA was uniformly dispersed in PAA. The mechanical properties of PAA/Se-HA30 composites included bending, compressive, and yield strengths at 83.07 ± 0.57, 106.56 ± 0.46, and 99.17 ± 1.11 MPa, respectively. The cellular responses of PAA/Se-HA compositesin vitrowere studied using bone marrow mesenchymal stem cells (BMSCs) by cell counting kit-8 assay, and results showed that PAA/Se-HA30 composites significantly promoted the proliferation of BMSCs at the concentration of 2 mg ml-1. The alkaline phosphatase activity (ALP) and alizarin red staining results showed that the introduction of Se-HA into PAA enhanced ALP activity and formation of calcium nodule. Western blotting and Real-time polymerase chain reaction results showed that the introduction of Se-HA into PAA could promoted the expression of osteogenic-related proteins and mRNA (integrin-binding sialoprotein, osteopontin, runt-related transcription factor 2 and Osterix) in BMSCs. A muscle defect at the back and a bone defect at the femoral condyle of New Zealand white rabbits were introduced for evaluating the enhancement of bone regeneration of PAA and PAA/Se-HA30 composites. The implantation of muscle tissue revealed good biocompatibility of PAA and PAA/Se-HA30 composites. The implantation of bone defect showed that PAA/Se-HA30 composites enhanced bone formation at the defect site (8 weeks), exhibiting good bone conductivity. Therefore, the PAA-based composite was a promising candidate material for bone tissue regeneration.

Functionalized Magnesium Phosphate Cement Induces In Situ Vascularized Bone Regeneration via Surface Lyophilization of Chondroitin Sulfate

Bone defect repair poses significant challenges in orthopedics, thereby increasing the demand for bone substitutes. Magnesium phosphate cements (MPCs) are widely used for bone defect repair because of their excellent mechanical properties and biodegradability. However, high crystallinity and uncontrolled magnesium ion (Mg2+) release limit the surface bioactivity of MPCs in bone regeneration. Here, we fabricate chondroitin sulfate (CS) as a surface coating via the lyophilization method, namely CMPC. We find that the CS coating is uniformly distributed and improves the mechanical properties of MPC through anionic electrostatic adsorption, while mediating degradation-related controlled ion release of Mg2+. Using a combination of in vitro and in vivo analyses, we show that the CS coating maintained cytocompatibility while increasing the cell adhesion area of MC3T3-E1s. Furthermore, we display accelerated osteogenesis and angiogenesis of CMPC, which are related to appropriate ion concentration of Mg2+. Our findings reveal that the preparation of a lyophilized CS coating is an effective method to promote surface bioactivity and mediate Mg2+ concentration dependent osteogenesis and angiogenesis, which have great potential in bone regeneration.

Fabrication of ACP-CCS-PVA composite membrane for a potential application in guided bone regeneration

The barrier membranes of guided bone regeneration (GBR) have been widely used in clinical medicine to repair bone defects. However, the unmatched mechanical strength, unsuitable degradation rates, and insufficient regeneration potential limit the application of the current barrier membranes. Here, amorphous calcium phosphate-carboxylated chitosan-polyvinyl alcohol (ACP-CCS-PVA) composite membranes are fabricated by freeze-thaw cycles, in which the ATP-stabilized ACP nanoparticles are uniformly distributed throughout the membranes. The mechanical performance and osteogenic properties are significantly improved by the ACP incorporated into the CCS-PVA system, but excess ACP would suppress cell proliferation and osteogenic differentiation. Our work highlights the pivotal role of ACP in GBR and provides insight into the need for biomaterial fabrication to balance mechanical strength and mineral content.

Microbially Synthesized Polymer-Metal Nanoparticles Composites as Promising Wound Dressings to Overcome Methicillin-Resistance Staphylococcus aureus Infections

Antimicrobial resistance has been declared one of the top 10 global public health threats. Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of recurring skin and soft tissue infections in patients with chronic skin conditions such as diabetic foot infections, making the treatment of the ulcers challenging. Wound dressings combined with metal nanoparticles have been suggested to prevent and treat MRSA-infected wounds. However, these particles are commonly synthesized by chemical approaches. In this study, we developed bio-based silver (Bio-AgNPs) and copper oxide nanoparticles (CuONPs) polymer composites using a microbially produced polyester from the Polyhydroxyalkanoates (PHAs) family. Poly(3-hydroxyoctanoate)-co-(3-hydroxyhexanoate) (PHO) was synthesized by Pseudomonas putida and functionalized in-situ with Bio-AgNPs or ex-situ with CuONPs. PHO-CuONPs films did not inhibit MRSA growth, while a reduction of 6.0 log CFU/mL was achieved with PHO-Bio-AgNPs synthesized from silver nitrate (AgNO₃) solution at 3.5 mM. Exposure of human fibroblast cells (HFF-1) to the bioactive films did not induce notable cytotoxicity and genotoxicity, as seen by a viability higher than 79% and no significant changes in basal DNA damage. However, exposure to PHO-Bio-AgNPs induced oxidative DNA damage in HFF-1 cells. No hemolytic potential was observed, while platelet aggregation was promoted and desired for wound healing. Here we demonstrate the biosynthesis of polymer-nanoparticle composites and their potential as bioactive films for MRSA treatment.

Bevacizumab encapsulation into PLGA nanoparticles functionalized with immunouteroglobin-1 as an innovative delivery system for atherosclerosis

Atherosclerosis represents one of the main causes of death in the Western world. It is a multifactorial pathology characterized by lesions that reduce the lumen of the vessels causing serious clinical events. The extradomain-B of fibronectin is overexpressed during angiogenesis and in tissues undergoing growth and extensive remodeling, i.e., atherosclerotic plaque. Bevacizumab is a recombinant humanized monoclonal antibody that can play a role against the angiogenesis process reducing the risk associated with this process in atherosclerosis. In this work, an innovative drug delivery device for target delivery of bevacizumab to the atherosclerotic lesion is proposed. A production protocol for poly(lactic-co-glycolic acid)-polyethylene glycol nanoparticles loaded with bevacizumab and functionalized with immunouteroglobin-1 was designed. Once immunouteroglobin-functionalized nanoparticles were produced, they were characterized regarding morphology, mean diameter, ζ-potential, association and conjugation efficiencies, bevacizumab release profile both in phosphate buffered saline and in serum, bevacizumab stability after release, cytocompatibility, and hemocompatibility. Nanoparticle mean diameter was in the range of 217-265 nm, their surface charge was between -21 and - 8 mV, and the association and conjugation efficiency of about 76 and 59 %, respectively. Fourier transform infrared spectroscopy analysis confirmed the functionalization of their surface with immunouteroglobin-1. In vitro assays showed that the studied nanoparticles were cytocompatible, once in contact with human endothelial and murine macrophages cell line up to 72 h, and hemocompatible, once in contact with red blood cells, at different concentrations of encapsulated BEV (0.1, 1, 10, and 100 μg_BEV/mL).

3D-printed reservoir-type implants containing poly(lactic acid)/poly(caprolactone) porous membranes for sustained drug delivery

Implantable drug delivery systems are an interesting alternative to conventional drug delivery systems to achieve local or systemic drug delivery. In this work, we investigated the potential of fused-deposition modelling to prepare reservoir-type implantable devices for sustained drug delivery. An antibiotic was chosen as a model molecule to evaluate the potential of this type of technology to prepare implants on-demand to provide prophylactic antimicrobial treatment after surgery. The first step was to prepare and characterize biodegradable rate-controlling porous membranes based on poly(lactic acid) (PLA) and poly(caprolactone) (PCL). These membranes were prepared using a solvent casting method. The resulting materials contained different PLA/PCL ratios. Cylindrical implants were 3D-printed vertically on top of the membranes. Tetracycline (TC) was loaded inside the implants and drug release was evaluated. The results suggested that membranes containing a PLA/PCL ratio of 50/50 provided drug release over periods of up to 25 days. On the other hand, membranes containing lower PCL content did not show a porous structure and accordingly the drug could not permeate to the same extent. The influence of different parameters on drug release was evaluated. It was established that film thickness, drug content and implant size are critical parameters as they have a direct influence on drug release kinetics. In all cases the implants were capable of providing drug release for at least 25 days. The antimicrobial properties of the implants were evaluated against E. coli and S. aureus. The resulting implants showed antimicrobial properties at day 0 and even after 21 days against both type of microorganisms. Finally, the biocompatibility of the implants was evaluated using endothelial cells. Cells exposed to implants were compared with a control group. There were no differences between both groups in terms of cell proliferation and morphology.

Reduced Platelet Adhesion for Blended Electrospun Meshes with Low Amounts of Collagen Type I

A clinically approved, tissue engineered graft is needed as an alternative for small-diameter artery replacement. Collagen type I is commonly investigated for naturally derived grafts. However, collagen promotes thrombosis, currently requiring a graft pre-seeding step. This study investigates unique impacts of blending low collagen amounts with synthetic polymers on scaffold platelet response, which would allow for viable acellular grafts that can endothelialize in vivo. While platelet adhesion and activation are confirmed to be high with 50% collagen samples, low collagen ratios surprisingly exhibit the opposite, anti-thrombogenic effect. Different platelet interactions in these blended materials can be related to collagen structure. Low collagen ratios show homogenous distribution of the components within individual fibers. Importantly, blended collagen scaffolds exhibit significant differences from gelatin scaffolds, including retaining percentage of collagen after incubation. These findings correlate with functional benefits including better endothelial cell spreading on collagen versus gelatin blended materials. This appears to differ from the current paradigm that processing with harsh solvents will irreversibly denature collagen into less desirable gelatin, but an important distinction is the interaction between collagen and synthetic materials during processing. Overall, excellent anti-thrombogenic properties of low collagen blends and benefits after grafting show promise for this vascular graft strategy.

High-performance bilayer composites for the replacement of osteochondral defects

Two novel bilayer constructs for the repair of osteochondral defects were developed from nanofibers and ceramic particles embedded into PVA matrices, exhibiting multiple promising properties similar to those of corresponding natural tissues.

Degradation and Characterisation of Electrospun Polycaprolactone (PCL) and Poly(lactic-co-glycolic acid) (PLGA) Scaffolds for Vascular Tissue Engineering

The current study aimed to evaluate the characteristics and the effects of degradation on the structural properties of Poly(lactic-co-glycolic acid) (PLGA)- and polycaprolactone (PCL)-based nanofibrous scaffolds. Six scaffolds were prepared by electrospinning, three with PCL 15% (w/v) and three with PLGA 10% (w/v), with electrospinning processing times of 30, 60 and 90 min. Both types of scaffolds displayed more robust mechanical properties with increased spinning times. The tensile strength of both scaffolds with 90-min electrospun membranes did not show a significant difference in their strengths, as the PCL and PLGA scaffolds measured at 1.492 MPa ± 0.378 SD and 1.764 MPa ± 0.7982 SD, respectively. All membranes were shown to be hydrophobic under a wettability test. A degradation behaviour study was performed by immersing all scaffolds in phosphate-buffered saline (PBS) solution at room temperature for 12 weeks and for 4 weeks at 37 °C. The effects of degradation were monitored by taking each sample out of the PBS solution every week, and the structural changes were investigated under a scanning electron microscope (SEM). The PCL and PLGA scaffolds showed excellent fibre structure with adequate degradation, and the fibre diameter, measured over time, showed slight increase in size. Therefore, as an example of fibre water intake and progressive degradation, the scaffold's percentage weight loss increased each week, further supporting the porous membrane's degradability. The pore size and the porosity percentage of all scaffolds decreased substantially over the degradation period. The conclusion drawn from this experiment is that PCL and PLGA hold great promise for tissue engineering and regenerative medicine applications.

Hemolytic, Biocompatible, and Functional Effect of Cellularized Polycaprolactone-Hydrolyzed Collagen Electrospun Membranes for Possible Application as Vascular Implants

In search of bioactive vascular prostheses that exhibit greater biocompatibility through the combination of natural and synthetic polymers, tissue engineering from a biomimetic perspective has proposed the development of three-dimensional structures as therapeutic strategies in the field of cardiovascular medicine. Techniques such as electrospinning allow obtaining of scaffolds that emulate the microarchitecture of the extracellular matrix of native vessels; thus, this study aimed to evaluate the biological influence of microarchitecture on polycaprolactone (PCL) and hydrolyzed collagen (H-Col) electrospun scaffolds, which have a homogeneous (microscale) or heterogeneous (micro-nanoscale) fibrillar structure. The hemolytic, biocompatible, and functional effect of the scaffolds in interaction with an in vitro fibroblast model was determined, in view of its potential use for vascular implants. Scaffolds were characterized by scanning electron microscopy and atomic force microscopy, Fourier transform infrared spectroscopy, wettability, static permeability, tensile test, and degradation. In addition, direct and indirect 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were used to identify the cell viability of fibroblasts, fluorescence assays were performed to establish morphological changes of the cell nuclei, and the hemolytic effect of the scaffolds was calculated. Results showed that ethanol-treated biocompositescaffolds exhibited mass losses lower than 6.65% and slow wettability and absorption, resulting from an increase in secondary structures that contribute to the crystalline phase of H-Col. The scaffolds demonstrated stable degradation in saline during the incubation period because of the availability of soluble structures in aqueous media, and the inclusion of H-Col increased the elastic properties of the scaffold. As regards hemocompatibility, the scaffolds had hemolysis levels lower than 1%; moreover, in terms of biocompatible characteristics, scaffolds exhibited good adhesion, proliferation, and cell viability and insignificant changes in the circularity of the cell nuclei. However, scaffolds with homogeneous fibers showed cell agglomerates after 48 h of interaction. By contrast, permeability decreased as the incubation period progressed, because of the cellularization of the three-dimensional structure. In conclusion, multiscale scaffolds could exhibit a suitable behavior as a bioactive small-diameter vascular implant.

A novel γ-PGA composite gellan membrane containing glycerol for guided bone regeneration

An ideal barrier membrane design should incorporate the function of a delivery vehicle for transporting drugs and osteoinductive factors to where the body is under inflammation. In the present study, a functional hydrogel-based barrier membrane is fabricated using calcium-form poly-γ-glutamic acid (γ-PGA) and glycerol blending into gellan gum. The concentration of the calcium-form poly-γ-glutamic acid (γ-PGA) and the glycerol ratio are studied for improving practicability in easy-handling and expanding the coverage area. Gellan gum-based membranes with uniformly distributed calcium aggregates are not only successfully manufactured but also providing excellent characteristics for protein adsorption, bioactivity, and bone cell maturation. Our composite gellan gum-based membranes were tested including to their morphology, mechanical properties, swelling behavior, protein adsorption, drug diffusion, and lysozyme degradation. The biocompatibility, proliferation, and osteoblastic response of membranes were examined by osteoblast-like (MG63) cells. Our results indicate that adequate physical cross-linking with γ-PGA improves the original mechanical properties and delays degradation. Growing glycerol ratio not only enhances the elongation at break and diffusion rate, but it also changes the tensile strength and the remaining weight. In vitro biocompatibility tests, an adequate ratio of γ-PGA modification significantly enhances the proliferation, the secretion of alkaline phosphatase (ALP) and mineralization. However, worth noting is the glycerol-modified membrane cannot bear a close resemblance with the non-glycerol group in the high level of osteoblastic response. In general, these tunable materials with biocompatibility, biodegradability, and positive osteoblastic responses were poised to be possible candidates for bone defect repair.

Antimicrobial and Biocompatible Polycaprolactone and Copper Oxide Nanoparticle Wound Dressings against Methicillin-Resistant Staphylococcus aureus

One of the major health problems linked to methicillin-resistant Staphylococcus aureus (MRSA) is severe diabetic foot ulcers (DFU), which are associated with hospital-acquired infections, lower limb amputations and emerging resistance to the current antibiotics. As an alternative, this work aims to develop a biodegradable and biocompatible material with antimicrobial capacity to prevent DFU. This was achieved by producing active polymeric films with metallic nanoparticles dispersed through a polycaprolactone (PCL) dressing. First, the antimicrobial activity of copper oxide nanoparticles (CuONPs) was tested by the microdilution method, selecting the lowest concentration that has an inhibitory effect on MRSA. Then, active PCL films were prepared and characterized in terms of their physicochemical properties, antimicrobial performance, cytotoxicity, genotoxicity and hemocompatibility. Active films had chemical and thermal properties like the ones without the antimicrobial agents, which was confirmed through FTIR, Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analysis. In relation to antimicrobial activity, active PCL films inhibited MRSA growth when treated with CuONPs at a concentration of 0.07% (w/w). After exposure to the active film extracts, human foreskin fibroblast cells (ATCC^® SCRC1041™) (HFF-1) exhibited a cell viability average above 80% for all treatments and no DNA damage was found. Finally, PCL films with 0.07% (w/w) CuONPs proved to be hemocompatible, and none of the films evaluated had red blood cell breakage greater than 5%, being within the acceptable limits established by the International Organization for Standardization ISO 10993-4:2002.

Hydroxyethyl Chitosan-Reinforced Polyvinyl Alcohol/Biphasic Calcium Phosphate Hydrogels for Bone Regeneration

Fabrication of reinforced scaffolds for bone regeneration remains a significant challenge. The weak mechanical properties of the chitosan (CS)-based composite scaffold hindered its further application in clinic. Here, to obtain hydroxyethyl CS (HECS), some hydrogen bonds of CS were replaced by hydroxyethyl groups. Then, HECS-reinforced polyvinyl alcohol (PVA)/biphasic calcium phosphate (BCP) nanoparticle hydrogel was fabricated via cycled freeze-thawing followed by an in vitro biomineralization treatment using a cell culture medium. The synthesized hydrogel had an interconnected porous structure with a uniform pore distribution. Compared to the CS/PVA/BCP hydrogel, the HECS/PVA/BCP hydrogels showed a thicker pore wall and had a compressive strength of up to 5-7 MPa. The biomineralized hydrogel possessed a better compressive strength and cytocompatibility compared to the untreated hydrogel, confirmed by CCK-8 analysis and fluorescence images. The modification of CS with hydroxyethyl groups and in vitro biomineralization were sufficient to improve the mechanical properties of the scaffold, and the HECS-reinforced PVA/BCP hydrogel was promising for bone tissue engineering applications.

[Research progress on the modification of guided bone regeneration membranes]

Guided bone regeneration (GBR) is an important technique to solve bone defect problems. In this technique, GBR barrier membranes play an irreplaceable role. GBR membranes can act as a barrier protecting fibroblasts from bone defects and promote osteoblast adhesion and proliferation, leading to bone regeneration. GBR barrier membranes should be enhanced because of the disadvantages of collagen membranes, which are extensively applied to the field of GBR. Therefore, various efforts have been devoted to modifying the antibacterial and osteogenic properties of GBR barrier membranes and developing novel materials. This article reviews the research advancements on the modification of GBR barrier membranes and discover future directions for the development of GBR barrier membranes to provide a reference for bone tissue engi-neering and repair.

Photocrosslinkable Nanofibrous Asymmetric Membrane Designed for Wound Dressing

Recently, the biomedical scientists who are working in the skin regeneration area have proposed asymmetric membranes as ideal wound dressings, since they are able to reproduce both layers of skin and improve the healing process as well as make it less painful. Herein, an electrospinning technique was used to produce new asymmetric membranes. The protective layer was composed of a blending solution between polycaprolactone and polylactic acid, whereas the underlying layer was comprised of methacrylated gelatin and chitosan. The chemical/physical properties, the in vitro hemo- and biocompatibility of the nanofibrous membranes were evaluated. The results obtained reveal that the produced membranes exhibited a wettability able to provide a moist environment at wound site. Moreover, the membranes' hemocompatibility and fibroblast cell adhesion, spreading and proliferation at the surface of the membranes were also noticed in the in vitro assays. Such results highlight the suitability of these asymmetric membranes for wound dressing applications.

Blood interactions with nano- and microfibers: Recent advances, challenges and applications in nano- and microfibrous hemostatic agents

Nanofibrous materials find a wide range of applications, such as vascular grafts, tissue-engineered scaffolds, or drug delivery systems. This phenomenon can be attributed to almost arbitrary biomaterial modification opportunities created by a multitude of polymers used to form nanofibers, as well as by surface functionalization methods. Among these applications, the hemostatic activity of nanofibrous materials is gaining more and more interest in biomedical research. It is therefore crucial to find both materials and nanofiber structural properties that affect organism responses. The present review critically analyzes the response of blood elements to natural and synthetic polymers, and their blends and composites. Also assessed in this review is the incorporation of pro-coagulative substances or drugs that can decrease bleeding time. The review also discusses the main animal models that were used to assess hemostatic agent safety and effectiveness. STATEMENT OF SIGNIFICANCE: The paper contains an in-depth review of the most representative studies recently published in the topic of nanofibrous hemostatic agents. The topic evolved from analysis of pristine polymeric nanofibers to multifunctional biomaterials. Furthermore, this study is important because it helps clarify the use of specific blood-biomaterial analysis techniques with emphasis on protein adsorption, thrombogenicity and blood coagulation. The paper should be of interest to the readers of Acta biomaterialia who are curious about the strategies and materials used for the development of multifunctional polymer nanofibers for novel blood-contacting applications.

* Engineering Membranes for Bone Regeneration

This review is focused on the use of membranes for the specific application of bone regeneration. The first section focuses on the relevance of membranes in this context and what are the specifications that they should possess to improve the regeneration of bone. Afterward, several techniques to engineer bone membranes by using "bulk"-like methods are discussed, where different parameters to induce bone formation are disclosed in a way to have desirable structural and functional properties. Subsequently, the production of nanostructured membranes using a bottom-up approach is discussed by highlighting the main advances in the field of bone regeneration. Primordial importance is given to the promotion of osteoconductive and osteoinductive capability during the membrane design. Whenever possible, the films prepared using different techniques are compared in terms of handability, bone guiding ability, osteoinductivity, adequate mechanical properties, or biodegradability. A last chapter contemplates membranes only composed by cells, disclosing their potential to regenerate bone.

Functional synergy of anti-mir221 and nanohydroxyapatite scaffold in bone tissue engineering of rat skull

An appropriate cell source, effective cell modification, and proper supportive matrices are the main bases of tissue engineering. The effectiveness of anti-mir221 or hydroxyapatite (HA) in improving the osteogenic differentiation of mesenchymal stem cells (MSCs) has been reported previously. Herein, simultaneous application of these osteogenic inducers was investigated in vivo. The Poly-caprolactone (PCL)/HA nanofibers were characterized using contact angle measurement, tensile test, Fourier transform infrared spectroscopy, and electron microscopy. Rat MSCs were isolated, characterized and transfected with anti-mir221. The rats were divided into 4 groups and an 8 mm defect were created in the mid-calvaria of each rat by trephine bur. Group 1 received (PCL)/HA nanofibers, group 2 received (PCL)/HA nanofibers plus autologous MSCs, group 3 received (PCL)/HA nanofibers plus MSCs transfected with anti-mir221, and group 4 rats were left empty as an additional control group. Histomorphometric and radiomorphometric evaluation after 4 and 8 weeks revealed more new bone formation in the cell-treated groups compared to the scaffold alone group. There was evidence for a combination of increased osteoclasts and osteoblast vascular lake containing red blood cells in the anti-mir221 transfected group. New bone penetration into the scaffolds empirically demonstrated the capability of this combination for efficient osteointegration. Altogether, the co-application of HA and anti-mir221 transfected cells can enhance bone healing of the rat skull.

From the printer: Potential of three-dimensional printing for orthopaedic applications

Three-dimensional (3D) printers can create complex structures based on digital models. The combination of medical diagnostic imaging with 3D printing has great potential in day-to-day clinics for patient-specific solutions and applications. In the musculoskeletal system, 3D printing is used to create custom-made implants, patient-specific instrumentation, and to regenerate tissues, in particular bone and cartilage. The major limiting factors for bioprinting include the lack of printing techniques with optimal printing resolution and materials with ideal mechanical strengths while maintaining cellular functionality. Before “tissues from the printer” can be widely applied, further research and development on improving and optimising printing techniques and biomaterials, and knowledge on the development of printed constructs into living tissues, is essential for future clinical application of this technology.