Pure Polycaprolactone Research Articles

Physicochemical and In Vitro Degradation Behaviors of Fibrous Membranes with Different Polycaprolactone and Gelatin Proportions.

Mechanical and degradation properties are crucial factors of guided tissue/bone regeneration (GTR/GBR) membranes. In this work, a series of fibrous membranes with different ratios of polycaprolactone (PCL) and gelatin (Gel) were prepared (PCL:Gel = 1:9 (P1G9), 3:7 (P3G7), 5:5 (P5G5), 7:3 (P7G3), and 9:1 (P9G1)) by electrospinning, and their physicochemical properties and In Vitro degradation behaviors were systematically investigated. Mechanical tests showed that tensile strength was enhanced with the presence of Gel, and the tensile strength of the P9G1 membrane reached nearly three times that of the pure PCL membrane. The degradation rate of the composite membranes could be adjusted by controlling the ratio of PCL and Gel; the higher the Gel content was, the faster the degradation of the PCL/Gel membrane. The higher PCL content favored maintaining the fibrous structure of the electrospun membranes. These findings will be beneficial for designing PCL/Gel composite materials for biomedical applications.

Synergetic effect of growth factor and topography on fibroblast proliferation

An innovative basic fibroblast growth factor (bFGF)-loaded polycaprolactone (PCL) fibrous membrane with highly aligned structure is developed for guided tissue regeneration (GTR). The aligned membrane is fabricated by electrospinning. In order to make efficient use of bFGF, PCL electrospun fibrous membrane is firstly surface-coated by self-polymerization of dopamine, and followed by immobilization of heparin via covalent conjugation to the polydopamine (PDA) layer. Subsequently, bFGF is loaded by binding to heparin. The loading yield of bFGF on heparin-immobilized PDA-coated PCL membrane significantly increases to around 7 times as compared with that of pure PCL membrane. NIH-3T3 cells show an enhanced proliferation and exhibit a stretched morphology aligned along the direction of the fibers on the aligned membranes. However, aligned bFGF-loaded PCL membrane exhibit a similar morphology but a highest cell density prolonged till 9 days. The synergetic effect of growth factor and topography would effectively regulate cell proliferation.

Effect of solvent on the physicochemical properties of electrospun nanocomposite with gamat oil and cerium oxide for potential medical engineering application

Wound healing is a complex and intricate process that has affected millions of people due to improper management. Scaffolds are capable of exhibiting an environment that is optimum for the regeneration of damaged tissues and hence, enhances the process of wound healing. The current study was done to fabricate nanocomposites composed of polycaprolactone (PCL) as well as gamat oil and cerium (Ce) oxide particles of different ratios through electrospinning that can be used in the healing of wounds. The polymeric solutions were dissolved in two different solvent systems to investigate the influence of solvent parameters on the physical properties of nanofibres. Solvent system A was a mixture of chloroform and dimethylformamide (DMF), while solvent system B was a mixture of acetone and DMF. Morphological analysis of fibre diameter indicated a decrease and the reduction of diameter was more pronounced in solvent system B rather than A. Contact angle measurements revealed that the addition of added constituents to pure PCL have increased its’ hydrophobicity nature for nanocomposites using both solvent systems. Fourier transform infrared spectroscopy (FTIR) results indicated chemical interactions between PCL, gamat oil and cerium oxide as detected through the shift in absorption bands. Lastly, mechanical testing of the nanocomposites indicated that using both solvent systems, there was an increase in the tensile strengths when gamat oil and Ce oxide were added. The newly fabricated nanocomposites using different solvent systems demonstrated physicochemical properties that are well suited for wound healing applications.

Osteogenic Differentiation Potential of Adipose-Derived Mesenchymal Stem Cells Cultured on Magnesium Oxide/Polycaprolactone Nanofibrous Scaffolds for Improving Bone Tissue Reconstruction.

Purpose: Recently, bone tissue engineering as a new strategy is used to repair and replace bone defects due to limitations in allograft and autograft methods. In this regard, we prepared nanofibrous scaffolds composed of polycaprolactone (PCL) and magnesium oxide (MgO) nanoparticles using the electrospinning technique for possible bone tissue engineering applications. Methods: The fabricated composites were characterized via scanning electron microscopy (SEM) imaging of scaffolds and seeded cells, water contact angle, DAPI staining, and MTT assay. Then osteogenic differentiation of adipose-derived mesenchymal stem cells cultured on this composite scaffold was determined by standard osteogenic marker tests, including alkaline phosphatase (ALP) activity, calcium deposition, and expression of osteogenic differentiation genes in the laboratory conditions. Results: The SEM analysis demonstrated that the diameter of nanofibers significantly decreased from 1029.25±209.349 µm to 537.83+0.140 nm, with the increase of MgO concentration to 2% (P < 0.05). Initial adhesion and proliferation of the adipose-derived mesenchymal stem cells on MgO/PCL scaffolds were significantly enhanced with the increasing of MgO concentration (P < 0.05). The 2% MgO/PCL nanofibrous scaffold showed significant increase in ALP activity (P < 0.05) and osteogenic-related gene expressions (Col1a1 and OPN) (P < 0.05) in compared to pure PCL and (0, 0.5 and 1%) MgO/PCL scaffolds. Conclusion: According to the results, it was demonstrated that MgO/PCL composite nanofibers have considerable osteoinductive potential, and taking together adipose-derived mesenchymal stem cells-MgO/PCL composite nanofibers can be a proper bio-implant to usage for bone regenerative medicine applications. Future in vivo studies are needed to determine this composite therapeutic potential.

SIFAT TRANSPARANSI DAN PERMEABILITAS FILM BIONANOKOMPOSIT POLYLACTIC ACID DAN POLYCAPROLACTONE DENGAN PENAMBAHAN NANOCRYSTALLINE CELLULOSE SEBAGAI PENGISI [Transparency and permeability properties of Bionanocomposite Film of Polylactic Acid and Polycaprolactone, and Nanocrystalline Cellulose as a Filler

Production of Polylactic acid (PLA)/Polycaprolactone (PCL) bionanocomposite films with various ratios was done by adding nanocrystalline celullose (NCC) from oil palm empty fruit bunches (OPEFB) as a filler. The aim of the research was to find out the effect of PLA/PCL ratio on film thickness, transparency of bionanocomposite films and water vapor permeability or WVP of the film bionanocomposite with addition of the 3% NCC. The PLA/PCL ratio are 1.0/0.0; 0.8/0.2; 0.6/0.4; 0.5/0.5; 0.4/0.6; 0.2/0.8; and 0.0/1.0, prepared with solvent casting method. Characterization of PLA/PCL bionanocomposites film performed was thickness, transparency test and water vapor permeability (WVP) test. The thickness of bionanocomposites film produced were around are about 0.036-0.053 mm, results show that the lower PLA/PCL ratio the thicker film obtained. The highest value of film transparency was obtained at a ratio of 1.0 / 0.0 (81.4% at a wavelength of 550 nm), the smaller the PLA / PCL ratio, the lower the value of transparency. The WVP value of PLA/PCL bionanocomposite films gives a lower value than the WVP value of pure PLA film and pure PCL film. The best WVP was obtained at a PLA/PCL ratio of 0.8/0.2 which was 1.49x10-16kg.m/(m2.s.Pa).

Fabrication and characterization of 3D printed biocomposite scaffolds based on PCL and zirconia nanoparticles

The application of three-dimensional printed polymer scaffolds in repairing bone defects is a promising strategy. Among them, polycaprolactone (PCL) scaffolds are widely studied due to their good processability and controlled degradation rate. However, as an alternative graft for repairing bone defects, PCL materials have poor hydrophilicity, which is not conducive to cell adhesion and growth. In addition, the poor mechanical properties of PCL materials cannot meet the strength required to repair bone defects. In this paper, nano-zirconium dioxide (ZrO2) powder is embedded in PCL material through a melt-mixing process, and a regular grid scaffold is constructed by 3D printing. The embedding of nanometer zirconium dioxide powder improves the hydrophilicity and water absorption of the composite scaffold, which is conducive to cell adhesion, proliferation and growth and is beneficial to the exchange of nutrients. Therefore, the PCL/ZrO2 composite scaffold showed better biological activity in vitro. At the same time, the PCL/ZrO2 composite material system significantly improves the mechanical properties of the scaffold. Among them, compared with the pure PCL scaffold, the Young’s modulus is increased by about 0.4 times, and the compressive strength is increased by about 0.5 times. In addition, the osteogenic differentiation results also showed that the PCL/ZrO2 composite scaffold group showed better ALP activity and more effective bone mineralization than the pure PCL group. We believe that the 3D printed PCL/ZrO2 composite scaffold has certain application prospects in repairing bone defects.

Fabrication of microfibrous PCL/MWCNTs scaffolds via melt-based electrohydrodynamic printing

Electrohydrodynamic (EHD) printing has attracted extensive attention in tissue engineering due to its unique capacity to mimic the fibrillar organizations of the native extracellular matrix. However, it is still a challenge to incorporate functional bionanomaterials into viscous polymer melts for melt-based EHD printing. Here a melt-based EHD printing process was developed to fabricate polycaprolactone (PCL)/multi-walled carbon nanotubes (MWCNTs) microfibrous scaffolds. The addition of MWCNT in PCL had little effect on the stability of melt-based EHD printing and simultaneously reduced the impedance of the resultant fibrous scaffolds. EHD-printed microfibrous PCL/MWCNTs composite scaffolds possessed similar mechanical properties to that of pure PCL scaffolds and showed good cytocompatibility for cellular spreading and proliferation in vitro. The presented strategy exhibits great promise to uniformly incorporate functional bionanomaterials into EHD-printed microfibrous architectures for specific biological functions.

Mechanical and Rheological Properties of Biodegradable Polycaprolactone/Carbon Nanotube Composites

The mechanical and rheological properties of new polymer composites based on polycaprolactone filled with single-walled carbon nanotubes are studied. All composites were prepared by hot melt compounding. Filling of polycaprolactone with carbon nanotubes in an amount from 0 to 1 wt.% leads to an increase in the elastic modulus by almost 75% and a twofold decrease in tensile strength and elongation at break compared to the pure polycaprolactone. With an increase in the content of carbon nanotubes, the melt flow index of the composites decreases by almost 10 times compared with the pure polycaprolactone.

Fabrication and Biological Activity of 3D-Printed Polycaprolactone/Magnesium Porous Scaffolds for Critical Size Bone Defect Repair.

Polycaprolactone (PCL) is widely used in bone tissue engineering due to its biocompatibility and mechanical strength. However, PCL is not biologically active and shows poor hydrophilicity, making it difficult for new bones to bind tightly to its surface. Magnesium (Mg), an important component of natural bone, exhibits good osteo-inductivity and biological activity. Therefore, porous PCL/Mg scaffolds, including pure PCL, PCL/5%Mg, PCL/10%Mg, and PCL/15%Mg, were prepared to elucidate whether the porous structure of scaffolds and the bioactivity of PCL may be enhanced via 3D printing and incorporation of Mg powder. Compared with the control group (pure PCL only), the hydrophilicity of composite PCL/Mg scaffolds was greatly increased, resulting in the scaffolds having decreased water contact angles. Tests for adhesion and proliferation of rat bone marrow mesenchymal stem cells (rBMSCs) indicated that the PCL/10%Mg scaffold showed superior compatibility. Furthermore, as indicated by alkaline phosphatase (ALP) activity and semiquantitative analysis of alizarin red staining, PCL/10%Mg scaffolds exhibited significantly stronger osteogenic activity than the other scaffolds. Animal experiments demonstrated that PCL/10%Mg scaffolds displayed pro-osteogenic effects at an early stage (4 weeks) and produced more new bone mass 8-12 weeks following implantation, compared with the control group. Visceral and blood parameter analyses indicated that PCL/10%Mg scaffolds did not exert any noticeable toxic effects. PCL/10%Mg composite scaffolds were found to promote bone defect repair at an early stage with good cytocompatibility. This finding revealed a new concept in designing bone tissue materials, which showed potential as a clinical treatment for bone defects.

Polycaprolactone/fluoride substituted-hydroxyapatite (PCL/FHA) nanocomposite coatings prepared by in-situ sol-gel process for dental implant applications

In this study, polycaprolactone (PCL) and polycaprolactone/fluoride substituted-hydroxyapatite (PCL/FHA) nanocomposite coatings at different composition (10, 20 and 30 wt.% of FHA) are deposited on alkali-treated Ti6Al4V substrate via in-situ sol-gel method to improve its corrosion behavior and in vitro bioactivity. The PCL and PCL/FHA nanocomposite coatings are characterized by scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The in vitro bioactivity and corrosion behavior of the coatings are also investigated to show their potential application for dental implants. The results indicate that the in-situ sol-gel process is capable of forming compact and crack-free coatings with a homogeneous dispersion of FHA as a ceramic phase in the polymeric matrix. By increasing the FHA content, the hydrophilicity, adhesion strength and surface roughness were increased. Furthermore, in vitro bioactivity of the PCL/FHA nanocomposite coatings was improved by increasing the FHA content and the incubation time in simulated body fluid (SBF). The corrosion resistance of the PCL/10 wt.% FHA coatings considerably increased as compared to the pure PCL and PCL/FHA coatings with 20 and 30 wt.% of FHA. Additionally, the MTT assay confirmed that the coatings have no considerable cytotoxicity effect and PCL/20 wt.% FHA coating promoted the proliferation and spreading of MG63 cells. Indeed, the results showed that the PCL/FHA nanocomposite coatings on alkali-treated Ti6Al4V substrate may be a promising candidate for dental implant applications.

Design of Thermoplastic 3D-Printed Scaffolds for Bone Tissue Engineering: Influence of Parameters of "Hidden" Importance in the Physical Properties of Scaffolds.

Additive manufacturing (AM) techniques are becoming the approaches of choice for the construction of scaffolds in tissue engineering. However, the development of 3D printing in this field brings unique challenges, which must be accounted for in the design of experiments. The common printing process parameters must be considered as important factors in the design and quality of final 3D-printed products. In this work, we study the influence of some parameters in the design and fabrication of PCL scaffolds, such as the number and orientation of layers, but also others of “hidden” importance, such as the cooling down rate while printing, or the position of the starting point in each layer. These factors can have an important impact oin the final porosity and mechanical performance of the scaffolds. A pure polycaprolactone filament was used. Three different configurations were selected for the design of the internal structure of the scaffolds: a solid one with alternate layers (solid) (0°, 90°), a porous one with 30% infill and alternate layers (ALT) (0°, 90°) and a non-alternated configuration consisting in printing three piled layers before changing the orientation (n-ALT) (0°, 0°, 0°, 90°, 90°, 90°). The nozzle temperature was set to 172 °C for printing and the build plate to 40 °C. Strand diameters of 361 ± 26 µm for room temperature cooling down and of 290 ± 30 µm for forced cooling down, were obtained. A compression elastic modulus of 2.12 ± 0.31 MPa for n-ALT and 8.58 ± 0.14 MPa for ALT scaffolds were obtained. The cooling down rate has been observed as an important parameter for the final characteristics of the scaffold.

Fabrication and Characterization of Fe(III) Metal-organic Frameworks Incorporating Polycaprolactone Nanofibers: Potential Scaffolds for Tissue Engineering

Fabrication of nanofibrous scaffolds of biodegradable polymers provides a great premise for several biological applications. In this study, nanofibrous polycaprolactone (PCL) mats incorporating Fe-MOF (PCL/x%Fe-MOF, x=5, 10, 20) were fabricated by electrospinning technique. The Fe-MOFs were separately synthesized by the hydrothermal method and then were added to PCL solution for preparation of nanofibrous composites. The presence of Fe-MOF in the fibers was demonstrated by various methods including FT-IR (Fourier-transform infrared), PXRD (powder X-ray diffraction), EDS (energy dispersive X-ray spectroscopy) mapping, SEM (scanning electron microscope), and TEM (transmission electron microscope). In the FT-IR spectra of the nanocomposites, the characteristic bands for the pure PCL and Fe-MOF showed no significant change in their positions, suggesting a weak chemical interaction with each other, although they physically mixed uniformly. Nanofibrous structure of the as-prepared nanocomposites was confirmed by SEM and TEM images. The diameter of PCL nanofibers was measured to be 369 nm. Biological investigations indicated that the experimented scaffolds including PCL/5%Fe-MOF and PCL/10%Fe-MOF nanofibrous scaffolds provided appropriate surface and mechanical properties such as cellular biocompatibility, high porosity, chemical stability, and optimum fiber diameter for cell adhesion, viability, and proliferation compared with PCL and PCL/20%Fe-MOF nanocomposites. Indeed, our results demonstrated that percent of Fe-MOF in the composites played a significant role in cell attachment and viability. Also, according to the implantation studies, up to at least 4 weeks, none of the animals showed any inflammatory response. Totally, we can be claimed that the modified electrospun scaffolds have been developed for tissue engineering applications.

Polyhydroxyphenylvalerate/polycaprolactone nanofibers improve the life-span and mechanoresponse of human IPSC-derived cortical neuronal cells.

The physico-chemical characteristics of the extracellular matrix (ECM) cause mechanical cues that could elicit responses in the survival rate of cortical neuronal cells. Efficient neurite outgrowth in vitro, is critical for successful cultivation of cortical neuronal cells and the potential for attempts at regeneration of the central nervous system (CNS) in vivo. Relatively soft and hydrophilic, microbially synthesized aromatic polyester, polyhydroxyphenylvalerate (PHPV) was blended 50:50 with the stiff and hydrophobic polycaprolactone (PCL) and electrospun in microfibers for use in a 3D (CellCrown™) configuration and in a 2D coverslip coated configuration. This blend allows a 2.3-fold increase in the life-span of human induced pluripotent stem derived cortical neuronal cells (hiPS) compared to pure PCL fibers. HiPS-derived cortical neuronal cells grown on PHPV/PCL fibers show a 3.8-fold higher cumulative neurite elaboration compared to neurites grown on PCL fibers only. 96% of cortical neuronal cells die after 8days of growth when plated on PCL fibers alone while >83% and 55% are alive on PHPV/PCL fibers on day 8 and day 17, respectively. An increased migration rate of cortical neuronal cells is also promoted by the blend compared to the PCL fibers alone. The critical survival rate improvement of hiPS derived cortical neuronal cells on PHPV/PCL blend holds promise in using these biocompatible nanofibers as implantable materials for regenerative purposes of an active cortical neuronal population after full maturation in vitro.

Electroactive 3D Printed Scaffolds Based on Percolated Composites of Polycaprolactone With Thermally Reduced Graphene Oxide for Antibacterial and Tissue Engineering Applications.

Applying electrical stimulation (ES) could affect different cellular mechanisms, thereby producing a bactericidal effect and an increase in human cell viability. Despite its relevance, this bioelectric effect has been barely reported in percolated conductive biopolymers. In this context, electroactive polycaprolactone (PCL) scaffolds with conductive Thermally Reduced Graphene Oxide (TrGO) nanoparticles were obtained by a 3D printing method. Under direct current (DC) along the percolated scaffolds, a strong antibacterial effect was observed, which completely eradicated S. aureus on the surface of scaffolds. Notably, the same ES regime also produced a four-fold increase in the viability of human mesenchymal stem cells attached to the 3D conductive PCL/TrGO scaffold compared with the pure PCL scaffold. These results have widened the design of novel electroactive composite polymers that could both eliminate the bacteria adhered to the scaffold and increase human cell viability, which have great potential in tissue engineering applications.

Aligned nanofibers of decellularized muscle extracellular matrix for volumetric muscle loss

Volumetric muscle loss (VML) is a traumatic loss of muscle tissue that results in chronic functional impairment. When injured, skeletal muscle is capable of small-scale repair; however, regenerative capacities are lost with VML due to a critical loss stem cells and extracellular matrix (ECM). Consequences of VML include either long-term disability or delayed amputations of the affected limb. While the prevalence of VML is substantial, currently a successful clinical therapy has not been identified. In a previous study, an electrospun composed of polycaprolactone (PCL) and decellularized-ECM (D-ECM) supported satellite cell-mediated myogenic activity in vitro. In this study, we investigate the extent to which this electrospun scaffold can support functional muscle regeneration in a murine model of VML. Experimental groups included no treatment, pure PCL treated, and PCL:D-ECM (50:50 blend) treated VML defects. The PCL:D-ECM scaffold treated VML muscles supported increased activity of anti-inflammatory M2 macrophages (arginase+ ) at Day 28, compared to other experimental groups. Increased myofiber (MHC+ ) regeneration was observed histologically at both Days 7 and 28 post-trauma in blend scaffold treated group compared to PCL treated and untreated groups. However, improvements in muscle weights and force production were not observed. Future studies would evaluate muscle function at longer time-points post-VML injury to allow sufficient time for reinnervation of regenerated muscle fibers.

Biodegradable Electrically Conductive Polycaprolacton-Based Composites Filled with Carbon Nanotubes

Electrophysical, morphological, rheological, and structural properties of new polymer composites based on polycaprolactone filled with single-walled carbon nanotubes are studied. It is shown that the percolation threshold for the developed composites is observed when the carbon nanotubes content is about 0.1 wt %. It is found that the degree of crystallinity of the composites increases by more than 60% compared to the pure polycaprolactone. The addition of carbon nanotubes to the polymer matrix leads to a decrease in the average size of crystallites, while their number increases essentially. It is shown that the developed composites can be treated by extrusion. Even when the content of carbon nanotubes is 1.0 wt %, the melt flow index is at least 0.5 g/10 min

Three-dimensional directional nerve guide conduits fabricated by dopamine-functionalized conductive carbon nanofibre-based nanocomposite ink printing.

A potential issue in current nerve guides is that they do not transmit electrical nerve impulses between the distal and proximal end of an injured nerve, i.e. a synapse. Conductivity is a desirable property of an ideal nerve guide that is being considered for peripheral nerve regeneration. Most conductive polymers reported for the fabrication of tissue engineering scaffolds, such as polypyrrole and polyaniline, are non-biodegradable and possess weak mechanical properties, and thus cannot be fabricated into 3D structures. Herein, we have designed a new nanocomposite material composed of dopamine, carbon nanofibers (CNF) and polycaprolactone (PCL) for the fabrication of nerve conduits, which facilitates the growth and migration of neurons toward the targeted end of an injured nerve. This support and navigation of the scaffold leads to better sensory and motor function. The results showed that the mechanical properties of the printed PCL increased by 30% in comparison with the pure PCL film, which is comparable with human nerves. The in vitro cell study of human glioma cells showed that the printed lines provided support for neural cell attachment, migration and differentiation toward the targeted end. In contrast, in the absence of printed lines in the scaffold, the cells attach and grow in random directions, forming a flower shape (cell cluster) on the surface of PCL. Thus, the proposed scaffold is a promising candidate for nerve guide application based on its signal transmission and navigating neurons in a correct pathway towards the targeted end.

Upconversion 3D Printed Composite with Multifunctional Applications for Tissue Engineering and Photodynamic Therapy

Upconversion nanoparticles (UCNPs) are suitable materials for bioapplications due to their ability to emit visible light under near infrared (NIR) excitation, in the biological transparency range. Polycaprolactone(PCL)-based scaffolds are widely used in tissue engineering in combination with inorganic compounds to improve bioactivity and osteoconductive properties. This work proposes a 3D printed composite scaffold with upconversion property aiming at biomedical applications in therapy-stimulated bone repair and photodynamic therapy (PDT). The system combines PCL polymer, UCNPs-apatite and a PDT photosensitizer. Thermal and rheological behaviors of the composite were similar to pure PCL polymer. Mechanical properties were improved by adding UCNPs-apatite. The 3D printable composite presented upconversion property and potential for PDT application, which was demonstrated by singlet oxygen generation under 980 nm excitation. Cytotoxicity, genotoxicity and mutagenicity assays indicated no toxicological effects at low concentrations of rare earth elements. Taken together, a potential multifunctional material is proposed for biomedical applications.

Hydration-Enhanced Lubricating Electrospun Nanofibrous Membranes Prevent Tissue Adhesion.

Lubrication is the key to efficient function of human tissues and has significant impact on the comfort level. However, the construction of a lubricating nanofibrous membrane has not been reported as yet, especially using a one-step surface modification method. Here, bioinspired by the superlubrication mechanism of articular cartilage, we successfully construct hydration-enhanced lubricating nanofibers via one-step in situ grafting of a copolymer synthesized by dopamine methacrylamide (DMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) onto electrospun polycaprolactone (PCL) nanofibers. The zwitterionic MPC structure provides the nanofiber surface with hydration lubrication behavior. The coefficient of friction (COF) of the lubricating nanofibrous membrane decreases significantly and is approximately 65% less than that of pure PCL nanofibers, which are easily worn out under friction regardless of hydration. The lubricating nanofibers, however, show favorable wear-resistance performance. Besides, they possess a strong antiadhesion ability of fibroblasts compared with pure PCL nanofibers. The cell density decreases approximately 9-fold, and the cell area decreases approximately 12 times on day 7. Furthermore, the in vivo antitendon adhesion data reveals that the lubricating nanofiber group has a significantly lower adhesion score and a better antitissue adhesion. Altogether, our developed hydration-enhanced lubricating nanofibers show promising applications in the biomedical field such as antiadhesive membranes.

Untangling the co-effects of oriented nanotopography and sustained anticoagulation in a biomimetic intima on neovessel remodeling

Constructing a small-diameter artificial blood vessel with biological functions and mechanical compliance comparable to native tissues is still a major challenge in vascular tissue engineering. To address the issues of severe thrombosis and unsatisfactory long-term patency in small-diameter vascular grafts, herein we designed a specifically biomimetic intima with an oriented nanotopographical structure and covalently immobilized anticoagulant molecules. The mixture of heparinized silk fibroin (SF-Hep) and polycaprolactone (PCL) was used to produce oriented inner layer and pure PCL was used to fabricate vertically porous outer layer by a two-step cross-electrospinning. Our findings showed that the immobilized heparin significantly influenced adherence and activation of platelets while the oriented nanotopography mainly manipulated the elongation and aligned growth of endothelial cells as well as hemodynamics of blood flow. More importantly, two factors of the oriented structure and anticoagulation presented the obviously synergistic effects on rapid endothelialization, long-term patency and remodeling of neovessel. Consequently, the current study successfully combined biochemical induction of heparin molecule and biophysical stimulation of oriented nanotopography to create an off-the-shelf small-diameter vascular graft with excellent antithrombosis in the early stage and long-term patency in the late stage.