Polycaprolactone Hydroxyapatite Research Articles

A comprehensive bench-to-bed look into the application of gamma-sterilized 3D-printed polycaprolactone/hydroxyapatite implants for craniomaxillofacial defects, an in vitro, in vivo, and clinical study

This study investigates the safety and efficacy of 3D-printed polycaprolactone/hydroxyapatite (PCL/HA) scaffolds for patient-specific cranioplasty surgeries, employing liquid deposition modeling (LDM) technology. This research is pioneering as it explores the impact of gamma radiation on PCL/HA scaffolds and utilizes printing ink with the highest content of HA known in the composite. The mechanical, morphological, and macromolecular stability of the gamma-sterilized scaffolds were verified before implantation. Subsequent research involving animal subjects was conducted to explore the effects of sterilized implants. Eventually, three clinical cases were selected for the implantation studies as part of a phase 1 non-randomized open-label clinical trial. It was shown that a 25 kGy gamma-ray dose for sterilizing the printed implants did not alter the required geometrical precision of the printed implants. The implants exhibited well-distributed HA and strength comparable to cancellous bone. Gamma radiation reduced hydrophobicity and water uptake capacity without inducing pyrogenic or inflammatory responses. Personalized PCL/HA substitutes successfully treated various craniomaxillofacial defects, including trauma-induced facial asymmetry and congenital deformities. HA nanoparticles in the ink stimulated significant osteoconductive responses within three months of implantation. Moreover, the results revealed that while larger implants may exhibit a slower bone formation response in comparison to smaller implants, they generally had an acceptable rate and volume of bone formation. This clinical trial suggests the application of a sterilized PCL/HA composite for craniomaxillofacial surgery is safe and could be considered as a substitute for autologous bone.

Study on mechanical properties of dual-channel cryogenic 3D printing scaffold for mandibular defect repair.

Mandibular defect repair has always been a clinical challenge, facing technical bottleneck. The new materials directly affect technological breakthroughs in mandibular defect repair field. Our aim is to fabricate a scaffold of advanced biomaterials for repairing of small mandibular defect. Therefore, a novel dual-channel scaffold consisting of silk fibroin/collagen type-I/hydroxyapatite (SCH) and polycaprolactone/hydroxyapatite (PCL/HA) was fabricated by cryogenic 3D printing technology with double nozzles. The mechanical properties and behaviors of the dual-channel scaffold were investigated by performing uniaxial compression, creep, stress relaxation, and ratcheting experiments respectively. The experiments indicated that the dual-channel scaffold was typical non-linear viscoelastic consistent with cancellous tissue; the Young's modulus of this scaffold was 60.1kPa. Finite element analysis (FEA) was employed performing a numerical simulation to evaluate the implantation effect in mandible. The stress distribution of the contact area between scaffold and defect was uniform, the maximum Mises stress of cortical bone and cancellous bone in defect area were 54.520MPa and 3.196MPa, and the maximum displacement of cortical bone and cancellous bone in defect area were 0.1575mm and 0.1555mm respectively, which distributed in the incisor region. The peak maximum Mises stress experienced by the implanted scaffold was 3.128 × 10-3MPa, and the maximum displacement was 6.453 × 10-2mm distributed near incisor area. The displacement distribution of the scaffold was consistent with that of cortical and cancellous bone. The scaffold recovered well when the force applied on it disappeared. Above all, the dual-channel scaffold had excellent bio-mechanical properties in implanting mandible, which provides a new idea for the reconstruction of irregular bone defects in the mandible and has good clinical development prospects.

Development of Hydroxyapatite/Polycaprolactone Composite Biomaterials for Laser Powder Bed Fusion: Evaluation of Powder Characteristics, Mechanical Properties and Biocompatibility.

Hydroxyapatite/polycaprolactone (HA/PCL) composites have been extensively explored in laser powder bed fusion (L-PBF) for bone tissue engineering. However, conventional mechanical mixing methods for preparing composite powders often yield inhomogeneous compositions and suboptimal flowability. In this study, HA/PCL powders were prepared and optimized for L-PBF using the modified emulsion solvent evaporation method. The morphology, flowability and thermal and rheological properties of the powders were systematically investigated, along with the mechanical and biological properties of the fabricated specimens. The HA/PCL powders exhibited spherical morphologies with a homogeneous distribution of HA within the particles. The addition of small amounts of HA (5 wt% and 10 wt%) enhanced the processability and increased the maximum values of the elastic modulus and yield strength of the specimens from 129.8 MPa to 166.2 MPa and 20.2 MPa to 25.1 MPa, respectively, while also improving their biocompatibility. However, excessive addition resulted in compromised sinterability, thereby affecting both mechanical and biological properties.

Effect of Therapeutic Radiation on Polycaprolactone/Hydroxyapatite Biomaterials in a Calvarial Model.

Bone defects caused by cancer resection often require postoperative radiotherapy. Although various synthetic polymers have been introduced as graft materials, their biological behavior after radiation exposure remains unclear. Here, we investigated how polycaprolactone/hydroxyapatite (PCL/HA) implants respond to therapeutic radiation exposure (in terms of volume and bone regeneration). Four 8mm diameter calvaria defects were surgically created on the parietal bone of 6 rabbits. PCL/HA implants made of porous, solid, and hybrid polymers were grafted by random placement in each defect. The fourth defect was left untreated. Four weeks after surgery, radiation exposure was conducted weekly for 6 weeks (total: 48Gy). Micro-computed tomography and histologic analysis were performed at 3 and 6 months, and 6 months postradiation, respectively. The total augmented volumes of all implants showed no significant differences between 3- and 6-months postradiation computed tomography images. In histologic analysis, new bone areas were 0.45±0.11mm2, 2.02±0.34mm2, and 3.60±0.77mm2 in solid, hybrid, and porous polymer grafts, respectively. Bone regeneration was limited to the periphery of the defect in the hybrid and porous polymer grafts, whereas new bone formed inside the porous implant. The total augmented volume of the defect was maintained without significant absorption even after radiation exposure. The PCL/HA implant maintained its structure despite radiation exposure. The porous PCL/HA implant demonstrated excellent bone regeneration, followed by the hybrid and solid implants. The PCL/HA implant is a promising candidate for bone defect reconstruction.

BLUE CRAB SHELL WASTE VALORIZATION AS A SOURCE OF HYDROXYAPATITE FOR BIOCOMPATIBLE DENTAL IMPLANT COATING FABRICATION

In the presented work, the effect of hydroxyapatite/polycaprolactone (HAp/PCL) ratio and the immersion/withdrawal speed on the corrosion rate and antibacterial properties of Ti-6Al-4V ELI dental implant coating was investigated. Ti6Al-4V ELI implants are coated with different HAp-PCL ratios and immersion speeds. The functional groups of product hydroxyapatite were confirmed using the HAp standard JCPDS no. 09-0432, with crystallinity of 88.32% and ratio Ca/P at 2.12. The result shows that the higher concentrations of hydroxyapatite result in the decrease of corrosion rate and increased antibacterial activity reflected in larger inhibition zones. Additionally, the higher immersion and withdrawal speeds during dip-coating lead to lower corrosion rates. Furthermore, decreased corrosion rates may enhance the antibacterial properties of HAp-PCL coatings. These results demonstrate that the HAp/PCL composite can be considered as a prospective candidate for dental implant Ti-6Al-4V ELI coating.

Tuning the physiochemical properties of polycaprolactone-hydroxyapatite composite films by gamma irradiation for biomedical applications

Physiochemical properties of polycaprolactone-hydroxyapatite (PCL-HAp) composites were investigated in the pristine and after irradiation of γ rays (25, 50, 75, and 100 kGy). PCL-HAp composites were synthesized by solvent evaporation and characterized using spectroscopic methods as well as biological assays. The surface roughness (RMS) of the irradiated composite film (at 75 kGy) was 80 times higher than that of the pristine. Irradiation tailors the contact angle of the films from 77° to 90° (at 100 kGy). A decrease in particle size (at 100 kGy) of HAp nanorods in PCL-HAp composites film was observed. The XRD peak of PCL was slightly shifted from 21.2° to 21.7° (at 100 kGy) with the decrease in crystallite size. The peak intensity of the PCL and HAp altered on irradiation that was confirmed by FTIR and Raman analysis. Further, the bandgap of the irradiated film was lowered by 13 % (at 25 kGy). The luminescence intensity decreased due to the non-radiative process induced by the irradiation defects. All the samples possess hemocompatibility percentage of <10 % as per ASTM standards. At 75 kGy, fibroblast cell proliferation was higher than the pristine and other doses. The gamma-irradiated PCL-HAp composite films are potential candidates for tissue engineering applications.

Optimizing rheological properties for printability: low-temperature extrusion 3D printing of hydroxyapatite-polycaprolactone mixture inks for bone tissue engineering

Introduction: Low-temperature extrusion three-dimensional printing (LTE-3DP) using viscous ceramic-polymer inks has shown promise for bone tissue engineering. This process involves formulating a flowable ink by combining ceramic powders and other components with organic or inorganic polymer solutions, which can then be extruded through a 3D printer nozzle. LTE-3DP allows the incorporation of high fractions of bioactive ceramics and thermally labile additives such as drugs, proteins, and biomolecules into the inks to promote osteogenesis and bone regeneration. The rheology of the ink, influenced by various variables, significantly impacts the printability and form fidelity of the resulting scaffolds. These variables include the composition of the polymer solution and the size and weight ratio of ceramic microparticles. In this study, we posited that the printability of hydroxyapatite (HA) and polycaprolactone (PCL) mixture inks could be optimized by tailoring their rheological properties.Methods: We conducted a systematic investigation, varying the PCL weight percentage and HA:PCL weight ratio, to examine the effects of the ink’s composition on its viscosity and storage modulus, as well as its printability and the mechanical properties of 3D printed HA:PCL scaffolds.Results: We demonstrated that HA:PCL inks exhibit predictable non-Newtonian fluid behavior at higher fractions of HA, displaying significant shear thinning at elevated shear rates, which can facilitate extrusion through a 3D printing nozzle. We identified printable ink compositions based on filament continuity and scaffold form fidelity criteria. Moreover, we performed computational simulations to analyze the ink flow through an extrusion nozzle. These simulations utilized the Herschel-Bulkley-Papanastasiou constitutive model, considering the rheological properties obtained from experimental measurements. By combining experimental measurements and computational simulations, we formulated a non-dimensional Printability number that predicts whether an ink is printable based on the ink’s rheological parameters and printer-specific factors. Furthermore, we evaluated the compressive properties of printed HA:PCL scaffolds and characterized the effects of PCL% and HA:PCL ratio on the hyperelasticity observed in response to compressive deformations.Discussion: This hybrid approach using experimental rheology and FE simulations provides a framework to define the printability of ceramic-polymer ink formulations, which could help streamline the 3D printing of novel inks for bone tissue engineering.

Combined Effects of HA Concentration and Unit Cell Geometry on the Biomechanical Behavior of PCL/HA Scaffold for Tissue Engineering Applications Produced by LPBF.

This experimental study aims at filling the gap in the literature concerning the combined effects of hydroxyapatite (HA) concentration and elementary unit cell geometry on the biomechanical performances of additively manufactured polycaprolactone/hydroxyapatite (PCL/HA) scaffolds for tissue engineering applications. Scaffolds produced by laser powder bed fusion (LPBF) with diamond (DO) and rhombic dodecahedron (RD) elementary unit cells and HA concentrations of 5, 30 and 50 wt.% were subjected to structural, mechanical and biological characterization to investigate the biomechanical and degradative behavior from the perspective of bone tissue regeneration. Haralick's features describing surface pattern, correlation between micro- and macro-structural properties and human mesenchymal stem cell (hMSC) viability and proliferation have been considered. Experimental results showed that HA has negative influence on scaffold compaction under compression, while on the contrary it has a positive effect on hMSC adhesion. The unit cell geometry influences the mechanical response in the plastic regime and also has an effect on the cell proliferation. Finally, both HA concentration and elementary unit cell geometry affect the scaffold elastic deformation behavior as well as the amount of micro-porosity which, in turn, influences the scaffold degradation rate.

Polycaprolactone/hydroxyapatite coating on spark generated Mg surfaces to promote anticorrosion and interfacial adhesion strength

Surface coatings have been widely accepted to tailor the degradation rate of Mg alloys for bioimplant applications. Nevertheless, poor adhesion strength resulting in debonding and delamination compromises their corrosion resistance. In the present study, Polycaprolactone/Hydroxyapatite (PCL/HA) coatings have been developed on different textured Mg surfaces obtained under optimized low discharge energy (LDE) and high discharge energy (HDE) conditions of wire electric discharge machining (WEDM). Since discharge energy influences the surface texture of WEDMed Mg alloy, coating on LDE treated surface (LDEedcoated) and coating on the fine-polished surface (Polcoated) showed homogeneous and defect-free coating morphology with contact angles (CA) of 87.85°, 94.05° with simulated body Fluid (SBF) while coating on HDE treated surface (HDEedcoated) displayed spatial defects, lowering the CA. On the LDEedcoated sample, physical anchoring, H2 bonding, and electrostatic interactions combinedly improved the coating's adhesion strength to 9.91 N, 4.5 times higher than the polished counterpart. LDEedcoated samples significantly suppressed the Icorr to 9.74 × 10−9 A/cm2, resulting in 75 % and 99.8 % higher corrosion inhibition efficiency (ηc) after 24 h compared to Polcoated and HDEedcoated samples. After 7 days of in-vitro immersion, the hydrogen evolution rate (HER) of the LDEedcoated sample (0.034 mL/cm2/day) was nearly 2.8 and 35 times lower than Polcoated and HDEedcoated samples, respectively. Superior anticorrosion performance and Ca-P rich apatite growth on LDEedcoated samples significantly improved the cellular viability of L929 cells. WEDM treatments at LDE settings offer a facile method for the preparation of 'substrate-anchored' coating systems with enhanced interfacial adhesion and anticorrosion performance on Mg alloys for clinical translation.

In vitro evaluation of degradation, cytocompatibility and antibacterial property of polycaprolactone/hydroxyapatite composite coating on bioresorbable magnesium alloy

Polycaprolactone/hydroxyapatite (PCL/HA) composite coating was fabricated by a combination of hydrothermal and dipping methods to delay the degradation of Mg alloy AZ31 as bioresorbable materials. The PCL/HA coating was composed of nano rod-shape HA crystals and PCL filled in the space of HA crystals. Compared with the single HA coating, the binding strength between the PCL/HA composite coating and Mg alloy was obviously improved and the PCL/HA coating still adhered to the surface of AZ31 substrate even after 38 days of immersion. The electrochemical corrosion rate of HA coated sample was reduced by ten times after being filled by PCL. The electrochemical impedance spectroscopy (EIS) and immersion test results showed that the PCL/HA composite coating could provide a more effective barrier for Mg substrate than the HA coating alone. The cytocompatibility and the antibacterial property of HA coating and PCL/HA coating were evaluated by culturing with bone marrow-derived mesenchymal stem cells (BMSCs) and methicillin-resistant staphylococcus aureus (MRSA) for 24 h under direct culture conditions, respectively. The PCL/HA composite coating showed better BMSC cell compatibility, more suitable for BMSC adhesion than HA coating alone and showed a potential application prospect as a biological materials. However, from the perspective of clinical applications, the antibacterial property of PCL/HA composite coating needs to be further improved.

Supercritical Foaming and Impregnation of Polycaprolactone and Polycaprolactone-Hydroxyapatite Composites with Carvacrol

Polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) scaffolds were produced by foaming in supercritical carbon dioxide (scCO2) at 20 MPa, as well as in one-step foaming and impregnation process using carvacrol as an antibacterial agent with proven activity against Gram-positive and Gram-negative bacteria. The experimental design was developed to study the influence of temperature (40 °C and 50 °C), HA content (10 and 20 wt.%), and depressurization rate (one and two-step decompression) on the foams’ morphology, porosity, pore size distribution, and carvacrol impregnation yield. The characterization of the foams was carried out using scanning electron microscopy (SEM, SEM-FIB), Gay-Lussac density bottle measurements, and Fourier–transform infrared (FTIR) analyses. The obtained results demonstrate that processing PCL and PCL-HA scaffolds by means of scCO2 foaming enables preparing foams with porosity in the range of 65.55–74.39% and 61.98–67.13%, at 40 °C and 50 °C, respectively. The presence of carvacrol led to a lower porosity. At 40 °C and one-step decompression at a slow rate, the porosity of impregnated scaffolds was higher than at 50 °C and two- step fast decompression. However, a narrower pore size distribution was obtained at the last processing conditions. PCL scaffolds with HA resulted in higher carvacrol impregnation yields than neat PCL foams. The highest carvacrol loading (10.57%) was observed in the scaffold with 10 wt.% HA obtained at 50 °C.

Electrospun Polycaprolactone/Hydroxyapatite (PCL/HAp) microfibers as potential biomaterials for tissue engineering

Among several methods to fabricate microfiber based scaffolds, electrospinning is widely used due to its simplicity, low-cost and flexibility. In this study, fabrication of Polycaprolactone/Hydroxyapatite (PCL/HAp) microfibers by one-step electrospinning was investigated. HAp was synthesized via precipitation method using Ca(OH)2 and H3PO4 as the precursors. The effect of the electrospinning process parameters on morphology and diameter of PCL/HAp fibers was studied. Results indicated that precipitated HAp presented in spherical morphology and high crystallinity. The dispersion of HAp into PCL matrix was proved to produce the porous microfibers with interconnected pores. It is expected to improve mechanical performance and good bioactivity due to the incorporation of HAp. Furthermore, PCL/HAp fibrous scaffolds aim to mimic the extracellular matrix (ECM) structure and biological function if they were used in bone tissue regeneration.

Synthesis of Polycaprolactone-Hydroxyapatite (PCL-HA) Biodegradable Nanofibres Via an Electrospinning Technique for Tissue Engineering Scaffolds

The interest in biodegradable polymer nanofibres with tissue cell regeneration potential has increased in recent years. However, there are issues in the development of scaffolding to provide a favourable environment for cell proliferation and attachment. Such issues can be overcome by the addition of hydroxyapatite (HA), which is widely used in biomaterial applications. Biodegradable nanofibres of polycaprolactone (PCL) and hydroxyapatite (HA) have been produced by electrospinning. In this study, PCL was mixed with HA to synthesise nanofibres by single nozzle electrospinning. Furthermore, PCL-HA nanofibres were mixed with fibronectin to investigate the effect of adhesion of fibronectin to the surface of the PCL-HA nanofibres. The structure and morphology of nanofibres were determined by scanning electron microscopy (SEM), the chemical properties of nanofibres were analysed by Fourier transform infrared (FTIR), and the diameter and adhesive force of nanofibers and fibronectin were determined by an atomic force microscope (AFM). The SEM examination revealed the formation of cylindrical and smooth nanofibres with dense fibre networks when 10% HA was used, as HA can generate fibre. FTIR analysis indicated the presence of PCL and HA inside the nanofibres produced by electrospinning. The AFM examination showed that the PCL-HA nanofibres with 100 µg/ml of fibronectin gives the highest adhesion force which is important for the scaffold to resist the force from the external environment. This outcome resulted indicates that the PCL-HA nanofibers with fibronectin are promising for tissue engineering scaffold application. Hence, further investigations are needed to ensure the compatibility of living cells to survive and grow on the PCL-HA nanofibrous mats.

Effect of particle size, shape, and weight percentage of hydroxyapatite (HA) on rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composites

The aim of this study is to investigate the influence of hydroxyapatite’s (HA) particle size, shape, and variation of HA weight percentage on the rheological behaviour of polycaprolactone/hydroxyapatite (PCL/HA) composite. The composite was produced by melt blending process using a single screw extruder assisted with an ultrasonic wave with varied HA weight content (0 wt.%, 10 wt.%, 20 wt.%, 30 wt.% and 40 wt.%). Two types of HA were used, which are needle shape (HAN) and irregular shape (HAS). The rheological behaviour of the PCL/HA composite was investigated through the melt flow index (MFI) test at a varied temperature of 100, 110, and 120 °C. The result indicated that an increase of HA content decreases the MFI values of the PCL/HA composite. At similar content of HA, PCL/HAN composite has higher activation energy with lower MFI values compared to PCL/HAS composite. In conclusion, this study concluded that the particle size, shape, and weight percentage of HA significantly affect the rheological behaviour of PCL/HA composites.

Development of Hot‐Melt Extrusion Method to Produce Hydroxyapatite/Polycaprolactone Composite Filaments

The aim of this work is to develop a single‐step process to produce hydroxyapatite/polycaprolactone (HAp/PCL) composite filaments for 3D printing of bone scaffolds by fused deposition modeling (FDM). The HAp/PCL composite filaments are produced by hot‐melt extrusion, with direct in situ blending. For practical purposes, the effect of PCL particle size on filament homogeneity and printability is assessed between PCL in powder and pellet form. The effect of HAp content on processing parameters and filament properties is also evaluated. Filament extrudability, homogeneity, and shape consistency improve with increasing HAp content up to a threshold of 40 wt%. Furthermore, an optimal range of the composite melt viscosity for the extrusion process is defined. The produced filaments are successfully 3D printed by FDM and the resulting prototypes show improved compressive modulus and degradation rate with increasing HAp content. A cytocompatibility assay is conducted, which suggests an optimal HAp content to be less than 40 wt% in terms of cell viability, adhesion, and proliferation. The developed method offers several advantages, as it completely avoids the use of toxic solvents and enables the incorporation of very high HAp concentrations, further improving the chances of implementation of FDM for bone tissue regeneration medicine.

A comparative study of polycaprolactone–hydroxyapatite scaffold and collagen membrane carriers for recombinant human bone morphogenic protein-2 for guided bone regeneration

The polycaprolactone-30% hydroxyapatite (PCL-30%HA) scaffolds were fabricated using Melt Stretching and Multilayer Deposition (MSMD) technique. Different models of guided bone regeneration were evaluated in rat models. Group A, the calvarial defects were covered with collagen membranes. Group B, the scaffolds were placed into the defects and covered with the membranes. 200 µL of the 400 µg/mL BMP solution was slowly dripped onto the membranes. Group C, the scaffolds were soaked in the BMP solution before being placed. Group D, only the scaffolds were placed. Conclusively, the Group C model could enhance new bone formation better than the other models.

The combinatory effect of sinusoidal electromagnetic field and VEGF promotes osteogenesis and angiogenesis of mesenchymal stem cell-laden PCL/HA implants in a rat subcritical cranial defect

BackgroundRestoration of massive bone defects remains a huge challenge for orthopedic surgeons. Insufficient vascularization and slow bone regeneration limited the application of tissue engineering in bone defect. The effect of electromagnetic field (EMF) on bone defect has been reported for many years. However, sinusoidal EMF (SEMF) combined with tissue engineering in bone regeneration remains poorly investigated.MethodsIn the present study, we investigated the effect of SEMF and vascular endothelial growth factor (VEGF) on osteogenic and vasculogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs). Furthermore, pretreated rBMSC- laden polycaprolactone-hydroxyapatite (PCL/HA) scaffold was constructed and implanted into the subcritical cranial defect of rats. The bone formation and vascularization were evaluated 4 and 12 weeks after implantation.ResultsIt was shown that SEMF and VEGF could enhance the protein and mRNA expression levels of osteoblast- and endothelial cell-related markers, respectively. The combinatory effect of SEMF and VEGF slightly promoted the angiogenic differentiation of rBMSCs. The proteins of Wnt1, low-density lipoprotein receptor-related protein 6 (LRP-6), and β-catenin increased in all inducted groups, especially in SEMF + VEGF group. The results indicated that Wnt/β-catenin pathway might participate in the osteogenic and angiogenic differentiation of rBMSCs. Histological evaluation and reconstructed 3D graphs revealed that tissue-engineered constructs significantly promoted the new bone formation and angiogenesis compared to other groups.ConclusionThe combinatory effect of SEMF and VEGF raised an efficient approach to enhance the osteogenesis and vascularization of tissue-engineered constructs, which provided a useful guide for regeneration of bone defects.

Wharton’s jelly-derived mesenchymal stem cells and polycaprolactone/hydroxyapatite (PCL/HA) scaffold for bone tissue engineering

Background: Polycaprolactone (PCL) is a suitable polymer in the field of drug delivery and tissue engineering scaffolds.Aim of Work: This study aimed to design a Polycaprolactone /Nano hydroxyapatite (PCL/nHA10%) hybrid nanofiber scaffold and evaluate differentiation of Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) to osteogenic lineage on scaffolds for bone tissue engineering.Materials and Methods: In this study, PCL/nHA(10%) composite polymeric nano scaffolds were prepared by electrospinning. Mesenchymal stem cells were isolated from the Warton’s Jelly and cultured in the PCL/nHA 10% scaffold. Biocompatibility of scaffolds was confirmed by MTT assay. Characterization of umbilical cord mesencymal stem cells were performed using flow cytometry. The morphological and cell adhesion characteristics of mesenchymal stem cells (MSCs) on the scaffolds were performed using scanning electron microscopy (SEM) imaging. Finally, the cells were treated with osteogenic differentiation medium for 21 days to investigate their differentiation potential on the scaffolds and then differentiated cells were stained with alizarin red and von Kossa stains.Results: The largest pore size of PCL/nHA (10%) nanofibers was about 22 μm. The culture of WJ-MSCs on the scaffolds showed that the addition of nHA 10% to PCL scaffold caused further attachment and proliferation of the cells. The stained mineral deposit scaffold with alizarin red and von Kossa were also compared. In both types of staining, nano-composite scaffold showed higher calcium deposits.Conclusion: The results showed that the PCL/nHA 10% scaffolds for bone tissue engineering is a good choice, and can be used for bone tissue repair.

A laser-cutting-based manufacturing process for the generation of three-dimensional scaffolds for tissue engineering using Polycaprolactone/Hydroxyapatite composite polymer

A manufacturing process for sheet-based stacked scaffolds (SSCs) based on laser-cutting (LC) was developed. The sheets consist of Polycaprolactone/Hydroxyapatite (PCL/HA) composite material. Single sheets were cut from a PCL/HA foil and stacked to scaffolds with interconnecting pores of defined sizes. HA quantities up to 50% were processable with high reproducibility, while the accuracy was dependent on the applied laser power. The smallest achievable pore sizes were about 40 µm, while the smallest stable solid structures were about 125 µm. The human mesenchymal stem cell line SCP-1 was cultured on the manufactured PCL/HA scaffolds. The cells developed a natural morphology and were able to differentiate to functional osteoblasts. The generation of PCL/HA SSCs via LC offers new possibilities for tissue engineering (TE) approaches. It is reliable and fast, with high resolution. The SSC approach allows for facile cell seeding and analysis of cell fate within the three-dimensional cell culture, thus allowing for the generation of functional tissue constructs.

Dopamine modified and cartilage derived morphogenetic protein 1 laden polycaprolactone-hydroxyapatite composite scaffolds fabricated by three-dimensional printing improve chondrogenic differentiation of human bone marrow mesenchymal stem cells

To prepare dopamine modified and cartilage derived morphogenetic protein 1 (CDMP1) laden polycaprolactone-hydroxyapatite (PCL-HA) composite scaffolds by three-dimensional (3D) printing and evaluate the effect of 3D scaffolds on in vitro chondrogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A dimensional porous PCL-HA scaffold was fabricated by 3D printing. Dopamine was used to modify the surface of PCL-HA and then CDMP-1 was loaded into scaffolds. The surface microstructure was observed by scanning electron microscope (SEM) and porosity and water static contact angle were also detected. The cytological experiment in vitro were randomly divided into 3 groups: group A (PCL-HA scaffolds), group B (dopamine modified PCL-HA scaffolds), and group C (dopamine modified and CDMP-1 laden PCL-HA scaffolds). The hBMSCs were seeded into three scaffolds, in chondrogenic culture conditions, the cell adhesive rate, the cell proliferation (MTT assay), and cell activity (Live-Dead staining) were analyzed; and the gene expressions of collagen type Ⅱ and Aggrecan were detected by real-time fluorescent quantitative PCR. The scaffolds in 3 groups were all showed a cross-linked and pore interconnected with pore size of 400-500 μm, porosity of 56%, and fiber orientation of 0°/90°. For dopamine modification, the scaffolds in groups B and C were dark brown while in group A was white. Similarly, water static contact angle was from 76° of group A to 0° of groups B and C. After cultured for 24 hours, the cell adhesion rate of groups A, B, and C was 34.3%±3.5%, 48.3%±1.5%, and 57.4%±2.5% respectively, showing significant differences between groups ( P<0.05). Live/Dead staining showed good cell activity of cells in 3 groups. MTT test showed that hBMSCs proliferated well in 3 groups and the absorbance ( A) value was increased with time. The A value in group C was significantly higher than that in groups B and A, and in group B than in group A after cultured for 4, 7, 14, and 21 days, all showing significant differences ( P<0.05). The mRNA relative expression of collagen type Ⅱ and Aggrecan increased gradually with time in 3 groups. The mRNA relative expression of collagen type Ⅱafter cultured for 7, 14, and 21 days, and the mRNA relative expression of Aggrecan after cultured for 14 and 21 days in group C were significantly higher than those in groups A and B, and in group B than in group A, all showing significant differences ( P<0.05). Co-culture of dopamine modified and CDMP1 laden PCL-HA scaffolds and hBMSCs in vitro can promote hBMSCs' adhesion, proliferation, and chondrogenic differentiation.