PCL Scaffolds Research Articles

Multiscale SAXS/WAXD characterisation of the deformation mechanisms of electrospun PCL scaffolds

This research provides a thorough study of the mechanical response of PCL scaffolds and determines their deformation micromechanisms at different scales by a combination of experimental techniques (mechanical tests, scanning electron microscopy, wide angle X-ray diffraction and small-angle X-ray scattering). Scaffolds with different fibre orientation distribution functions were manufactured and subjected to tensile loading. The macromechanical properties were dictated the by the fibre deformation and interaction in terms of fibre straightening, rotation and stretching. The stiffness and the yield strength were directly proportional to the percentage of fibres oriented with the loading direction. The gradual deformation induced a progressive fibre rotation, uncurling and stretching, showing different impact at molecular level for each configuration. The fibres aligned with the loading direction presented a homogeneous plasticity with an inherent loss of the crystal phase, meanwhile the misaligned fibres exhibited a negligible loss of crystallinity due to a predominance of the fibre rotation. The fibre plasticity triggered the macromechanical yielding of the scaffold and for high levels of plastic deformation the fibres developed macromolecular fibrils and microvoids. These findings provide the fundamental observations to develop engineering tissues with highly tunable and tailored mechanical properties for site specific in vivo applications.

Modification of PCL Scaffolds by Reactive Magnetron Sputtering: A Possibility for Modulating Macrophage Responses

Modification of PCL Scaffolds by Reactive Magnetron Sputtering: A Possibility for Modulating Macrophage Responses

Electrospun PCL and PLA hybrid nanofibrous scaffolds containing Nigella sativa herbal extract for effective wound healing

AbstractBlack seed (Nigella sativa [NS]) is used in traditional medicine as an antibacterial agent. In this study, novel hybrid scaffolds were manufactured from poly(ɛ‐caprolactone[PCL])/ Poly(lactic acid [PLA]) with NS extract by double‐nozzle electrospinning for wound healing application. Optimal conditions were found using response surface methodology including feed rate 0.8 ml/hr, voltage 20 kV and PLA 8% /PCL 10% concentrations. The effect of NS extract on the properties of the scaffold was evaluated by scanning electron microscopy, contact angle, and mechanical test. The PLA‐PCL/NS 20% beadles, and smooth nanofibrous web was obtained as the optimum scaffold with an average diameter of 638 ± 69 nm and the contact angle of 44°. In addition, the biological properties of the scaffolds such as antibacterial against Staphylococcus aureus (gram‐positive) and Escherichia coli (gram‐negative) bacteria, MTT assay, extract release, and cell growth (human mesenchymal stem cells) were examined. Incorporation of NS extract into the nanofibers caused to enhance the biological properties, cell viability and cell proliferation without toxicity.

Modification of PCL Scaffolds by Reactive Magnetron Sputtering: A Possibility for Modulating Macrophage Responses

Direct current (DC) reactive magnetron sputtering is as an efficient method for enhancing the biocompatibility of poly(ε-caprolactone) (PCL) scaffolds. However, the PCL chemical bonding state, the composition of the deposited coating, and their interaction with immune cells remain unknown. Herein, we demonstrated that the DC reactive magnetron sputtering of the titanium target in a nitrogen atmosphere leads to the formation of nitrogen-containing moieties and the titanium dioxide coating on the scaffold surface. We have provided the possible mechanism of PCL fragmentation and coating formation supported by XPS results and DFT calculations. Our preliminary biological studies suggest that DC reactive magnetron sputtering of the titanium target could be an effective tool to control macrophage functional responses toward PCL scaffolds as it allows to inhibit respiratory burst while retaining cell viability and scavenging activity.

Layer by layer deposited osteoinductive scaffolds for bone tissue engineering

There are various bone regenerative and repair methods, but the use of osteoinductive scaffolds as bone grafts/substitute has gained wide importance worldwide. Here, an osteoinductive scaffold is developed which spontaneously stimulates stem cells to osteoblast formation without the use of any growth factor or differentiation media. We prepared electrospun PCL scaffold which is further modified for osteoinductivity by layer-by-layer method using graphene and Cissus quadrangularis callus culture extract (PCL-GP-CQ). The modified PCL-GP-CQ scaffold was compared with plain PCL scaffold and PCL coated only with GP. Physical properties such as roughness, wettability, yield strength and tensile strength of PCL-GP-CQ scaffold were found to be superior. Also, PCL-GP-CQ scaffold when seeded with human umbilical cord Wharton's jelly derived mesenchymal stem cells showed higher in vitro biocompatibility with enhanced cellular proliferation on its surface. Synergistic effect of graphene and Cissus Quadrangularis callus culture extract in scaffold boosted the differentiation of human Umbilical Cord Wharton’s jelly derived Mesenchymal Stem Cells into osteogenic lineage without any differentiation media in less than 20 days. The PCL-GP-CQ scaffold enhanced osteoblastic differentiation, osteoconduction and osteoinduction potential of scaffolds making them highly suitable for bone regeneration and bone tissue engineering applications.

Fabrication of biocompatible and bioabsorbable polycaprolactone/ magnesium hydroxide 3D printed scaffolds: Degradation and in vitro osteoblasts interactions

Biodegradable polymeric 3D implants are of considerable interest for biomedical applications, however the degradation profile and bioactivity are important considerations for many clinical applications. In this context, bioresorbable magnesium hydroxide (MH) nanoparticles (NPs) (<50 nm) were blended with the degradable polymer poly (ε-caprolactone) (PCL) at concentrations of 5 and 20 wt%, and the composite was manufactured by 3D printing technology. Efficient load transfer was found between the nanofiller and matrix PCL, which was reflected in changes in the tensile properties of the MH-based composite. A statistically significant 44.3% increase in tensile modulus was achieved by the addition of 5 wt% MH, which was in agreement with the Halpin-Tsai theoretical model. The incorporation of MH in the PCL scaffolds accelerated the weight loss of the scaffolds and decreased the molecular weight of PCL over a prolonged soaking period (150 days) in PBS solution (pH 7.37, 37 ± 0.5 °C). The PCL/MH composite scaffolds were shown to be non-cytotoxic in vitro, and ion diffusion into the cell culture media promoted osteoblast metabolic activity, attachment, and proliferation, as compared to PCL-only scaffolds. Moreover, osteoblastic activity, as assessed by the expression of alkaline phosphatase, was significantly higher on the composite PCL/MH scaffold after 14 and 21 days. In summary, the 3D PCL/MH composite scaffolds could enhance osteoblastic activity and demonstrated a moderately accelerated degradation profile, which are characteristics that can be considered favorable for bone regeneration applications.

Facile Strategy on Hydrophilic Modification of Poly(ε-caprolactone) Scaffolds for Assisting Tissue-Engineered Meniscus Constructs In Vitro.

Poly(ε-caprolactone) (PCL) derived scaffolds have been extensively explored in the field of tissue-engineered meniscus (TEM) originating from their good biosafety and biomechanical properties. However, the poor intrinsic hydrophobicity severely hindered their wide applications for the scaffold-assisted tissue regeneration. Herein, we developed a simple strategy on surface modification of three-dimensional (3D) PCL scaffolds via a simply soaking treatment of sodium hydroxide (NaOH) solutions to increase the hydrophilicity and roughness of scaffolds' surfaces. We investigated the effect of hydrolysis degree mediated by NaOH solutions on mechanical properties of 3D scaffolds, considering the importance of scaffolds' resistance to internal force. We also investigated and analyzed the biological performances of mesenchymal stromal cells (MSCs) and meniscal fibrocartilage cells (MFCs) onto the scaffolds treated or untreated by NaOH solutions. The results indicated that hydrophilic modification could improve the proliferation and attachment of cells on the scaffolds. After careful screening process condition, structural fabrication, and performance optimization, these modified PCL scaffolds possessed roughened surfaces with inherent hierarchical pores, enhanced hydrophilicity and preferable biological performances, thus exhibiting the favorable advantages on the proliferation and adhesion of seeded cells for TEM. Therefore, this feasible hydrophilic modification method is not only beneficial to promote smarter biomedical scaffold materials but also show great application prospect in tissue engineering meniscus with tunable architectures and desired functionalities.

Tympanic Membrane Collagen Expression by Dynamically Cultured Human Mesenchymal Stromal Cell/Star-Branched Poly(ε-Caprolactone) Nonwoven Constructs

The tympanic membrane (TM) primes the sound transmission mechanism due to special fibrous layers mainly of collagens II, III, and IV as a product of TM fibroblasts, while type I is less represented. In this study, human mesenchymal stromal cells (hMSCs) were cultured on star-branched poly(ε-caprolactone) (*PCL)-based nonwovens using a TM bioreactor and proper differentiating factors to induce the expression of the TM collagen types. The cell cultures were carried out for one week under static and dynamic conditions. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to assess collagen expression. A Finite Element Model was applied to calculate the stress distribution on the scaffolds under dynamic culture. Nanohydroxyapatite (HA) was used as a filler to change density and tensile strength of *PCL scaffolds. In dynamically cultured *PCL constructs, fibroblast surface marker was overexpressed, and collagen type II was revealed via IHC. Collagen types I, III and IV were also detected. Von Mises stress maps showed that during the bioreactor motion, the maximum stress in *PCL was double that in HA/*PCL scaffolds. By using a *PCL nonwoven scaffold, with suitable physico-mechanical properties, an oscillatory culture, and proper differentiative factors, hMSCs were committed into fibroblast lineage-producing TM-like collagens.

Acetylated hyaluronic acid effectively enhances chondrogenic differentiation of mesenchymal stem cells seeded on electrospun PCL scaffolds

Construction of scaffolds which are similar to natural niches regarding both biochemical composition and mechanical characteristics has gained great attention in the field of tissue engineering. However, application of natural polymers, such as hyaluronic acid, is challenging in construction of scaffolds due to physicochemical properties, difficult to use in electrospinning and low cell adhesion rate. In this study, HA was acetylated to make it soluble in high polarity solvent and blended with PCL for construction of nanofibrous composite (ac-HA/PCL) scaffolds. Chondroinductivity of the constructed scaffolds was investigated using human mesenchymal stem cells (hADSCs). The presence of acetyl groups, as well as morphology and biocompatibility of the composite scaffolds were characterized by HNMR, FTIR, SEM and MTT assay respectively. Expression of cartilage-specific genes (SOX9, Col II and Aggrecan) was monitored by Real-time PCR. Significant increase in expression of Sox9 and Col II as the markers of chondrogenic differentiation as well as the results of Alcian blue staining, indicated the chondro-inductive potential of HA/PCL nanofibrous scaffolds. Acetylated HA was biocompatible with chondroinductivity features, therefore it not only had the positive characteristics of natural HA, but also enhanced the cellular attachment and application potential.

Construction of 3D fibrous PCL scaffolds by coaxial electrospinning for protein delivery.

In this study, a three-dimensional tablet-like porous scaffold, comprising core-shell fibers to host proteins inside the core, was developed. The fabrication method involved the novel combination of coaxial and wet electrospinning in a single setting. Poly (ε-caprolactone) was chosen as the based polymer and bovine serum albumin was used as a model protein. These 3D tablet-like scaffolds exhibited adequate porosity and suitable pore size for cell culture and cell infiltration, in addition to appropriate mechanical properties for cartilage tissue engineering. The effects of different parameters on the behavior of the system have been studied and the 3D scaffold based on the core-shell fiber was compared with that based on the matrix fiber. The core-shell structure showed superior performance in comparison to the matrix structure by sustaining protein release kinetics at least for 12days in PBS. The results from in vitro cell cytotoxicity study revealed that the presented scaffold was biocompatible and non-toxic. Coaxial electrospinning was shown to be a versatile technique in achieving the delivery of biochemical signals in a controlled manner for the regeneration of cartilage. These 3D tablet-like PCL scaffolds incorporated with protein solutions are engineered systems that closely mimic the characteristics of cartilage tissue.

PCL Scaffold for Osteochondral Defect Treatment

Osteochondral defects develop as a result of trauma, microtrauma, avascular necrosis or cancer. These are usually pre-arthrotic conditions, accompanied by chronic pain and limited joint mobility leading to decreased quality of life of the affected patients. The bone itself has self-repair potential facilitated by mesenchymal stem cells and other cells present in the bone tissue. On the other hand, mature cartilage has very low regenerative capacity due to limited mitotic potential of chondrocytes and lack of vascularization. Therefore, there is an effort to develop an alternative treatment strategy supporting and accelerating natural healing processes. We have designed nanofibrous scaffolds made of poly‑ε‑caprolactone/hyaluronic acid and enriched with specific growth factors – “osteogenic” part with BMP‑2 and “chondrogenic” part with bFGF and TGF‑β. These two parts are meant to be combined in one biphasic non‑cellular scaffold which would be possible to implant in the site of injury and serve as a mechanical support for the cells. We examined proliferation and viability of cells, depth of their penetration into scaffold, cell distribution, alkaline phosphatase activity and extracellular matrix proteins expression. We showed both “osteogenic” and “chondrogenic” scaffold was suitable for cell growth. Moreover, in comparison to the control samples, these two scaffolds exhibited positive effect on chondrogenic and osteogenic differentiation, respectively.

A comparison between electrospinning and rotary-jet spinning to produce PCL fibers with low bacteria colonization.

One of the important components in tissue engineering is material structure, providing a model for fixing and the development of cells and tissues, which allows for the transport of nutrients and regulatory molecules to and from cells. The community claims the need for new materials with better properties for use in the clinic. Poly (ε-caprolactone) (PCL) is a biodegradable polymer, semi crystalline, with superior mechanical properties and has attracted an increasing interest due to its usefulness in various biomedical applications. Herein, two different methods (electrospinning versus rotary jet spinning) with different concentrations of PCL produced ultra thin-fibers each with particular characteristics, verified and analyzed by morphology, wettability, thermal and cytotoxicity features and for bacteria colonization. Different PCL scaffold morphologies were found to be dependent on the fabrication method used. All PCL scaffolds showed greater mammalian cell interactions. Most impressively, rotary-jet spun fibers showed that a special rough surface decreased bacteria colonization, emphasizing that no nanoparticle or antibiotic was used; maybe this effect is related with physical (scaffold) and/or biological mechanisms. Thus, this study showed that rotary jet spun fibers possess a special topography compared to electrospun fibers to reduce bacteria colonization and present no cytotoxicity when in contact with mammalian cells.

Novel poly(ε-caprolactone) scaffolds comprised of tailored core/shell-structured filaments using 3D plotting technique

This study presents a novel type of poly(ε-caprolactone) (PCL) scaffold comprised of tailored core/shell-structured filaments. The scaffold can be produced using a nonsolvent-induced phase separation phenomenon during the 3D plotting of PCL solutions in a coagulation bath. Specifically, a mixture of water and ethanol was employed as the nonsolvent, in order to tailor the phase separation behavior of a PCL/acetone solution. The addition of water to ethanol allowed for the creation of dense shells due to the fast exchange between acetone and water during the early stage of the 3D plotting process, while in the cores a number of micropores were formed. In addition, the thickness of the dense shell increased with an increase in water content in the water/ethanol mixture, increasing the mechanical properties (i.e., tensile strength, modulus, and strain at failure) of the porous PCL scaffolds with tailored core/shell-structured filaments remarkably.

One-pot porogen free method fabricated porous microsphere-aggregated 3D PCL scaffolds for bone tissue engineering.

Three-dimensional (3D) scaffolds with interconnected, hierarchically structured pores, and biomimetic nanostructures are desirable for tissue engineering, where preparation with a facile and biocompatible strategy remains challenging. In the present work, an innovative porous microspheres-aggregated 3D PCL scaffold with macropores, micropores, and nanofibrous-like structures was fabricated through a one-pot thermally induced phase separation (TIPS) method without the use of any porogen or specific instruments. Importantly, the porosity, pore size, and mechanical properties of our scaffolds were tailorable through tuning of the polymer concentration. Interestingly, the bioactivity of our 3D PCL scaffolds was significantly improved, as abundant apatite-like layers were formed on the 3D porous scaffolds, while no obvious apatite was observed on the 2D flat PCL film. Moreover, the high surface area attributed to the hierarchical macro/micro/nanostructure enabled our 3D porous scaffold to serve as a drug delivery depot for sustained release of both small molecule drug (phenamil) and protein (BMP2). In addition to sustained drug release, the hierarchical structure and high mechanical properties also contribute to significantly improving BMP2-induced osteogenic differentiation. In summary, we developed a novel PCL porous scaffold through a facile, one-pot TIPS method and demonstrated its promising potential application in large bone defect repair.

Single-step, acid-based fabrication of homogeneous gelatin-polycaprolactone fibrillar scaffolds intended for skin tissue engineering

Blends of natural and synthetic polymers have recently attracted great attention as scaffolds for tissue engineering applications due to their favorable biological and mechanical properties. Nevertheless, phase-separation of blend components is an important challenge facing the development of electrospun homogeneous fibrillar natural-synthetic polymers scaffolds; phase-separation can produce significant detrimental effects for scaffolds fabricated by electrospinning. In the present study, blends of gelatin (Gel; natural polymer) and polycaprolactone (PCL; synthetic polymer), containing 30 and 45 wt% Gel, were prepared using acetic acid as a ‘green’ sole solvent to straightforwardly produce appropriate single-step Gel-PCL solutions for electrospinning. Miscibility of Gel and PCL in the scaffolds was assessed and the morphology, chemical composition and structural and solid-state properties of the scaffolds were thoroughly investigated. Results showed that the two polymers proved miscible under the single-step solution process used and that the electrospun scaffolds presented suitable properties for potential skin tissue engineering applications. Viability, metabolic activity and protein expression of human fibroblasts cultured on the Gel-PCL scaffolds were evaluated using LIVE/DEAD (calcein/ethidium homodimer), MTT-Formazan and immunocytochemistry assays, respectively. In vitro results showed that the electrospun Gel-PCL scaffolds enhanced cell viability and proliferation in comparison to PCL scaffolds. Furthermore, scaffolds allowed fibroblasts expression of extracellular matrix proteins, tropoelastin and collagen Type I, in a similar way to positive controls. Results indicated the feasibility of the single-step solution process used herein to obtain homogeneous electrospun Gel-PCL scaffolds with Gel content ≥30 wt% and potential properties to be used as scaffolds for skin tissue engineering applications for wound healing.

Chondrogenic differentiation of mesenchymal stem/stromal cells on 3D porous poly (ε-caprolactone) scaffolds: Effects of material alkaline treatment and chondroitin sulfate supplementation

Cartilage defects resultant from trauma or degenerative diseases (e.g., osteoarthritis) can potentially be repaired using tissue engineering (TE) strategies combining progenitor cells, biomaterial scaffolds and bio-physical/chemical cues. This work examines promoting chondrogenic differentiation of human bone marrow mesenchymal stem/stromal cells (BM-MSCs) by combining the effects of modified poly (ε-caprolactone) (PCL) scaffolds hydrophilicity and chondroitin sulfate (CS) supplementation in a hypoxic 5% oxygen atmosphere. 3D-extruded PCL scaffolds, characterized by μCT, featured a 21mm-1 surface area to volume ratio, 390μm pore size and approximately 100% pore interconnectivity. Scaffold immersion in sodium hydroxide solutions for different periods of time had major effects in scaffold surface morphology, wettability and mechanical properties, but without improvements on cell adhesion. In-situ chondrogenic differentiation of BM-MSC seeded in 3D-extruded PCL scaffolds resulted in higher cell populations and ECM deposition along all scaffold structure, when chondrogenesis was preceded by an expansion phase. Additionally, CS supplementation during BM-MSC expansion was crucial to enhance aggrecan gene expression, known as a hallmark of chondrogenesis. Overall, this study presents an approach to tailor the wettability and mechanical properties of PCL scaffolds and supports the use of CS-supplementation as a biochemical cue in integrated TE strategies for cartilage regeneration.

Reinforcement of electrospun polycaprolacton scaffold using KIT-6 to improve mechanical and biological performance

Electrospinning has been extensively accepted as one of most important techniques for fabrication of scaffolds for bone tissue engineering. Polycaprolactone is one of the most applied electro-spinned scaffolds. Since low mechanical strength of polycaprolactone scaffold leads to the limitation of its applications, composition of polycaprolactone with ceramic particles is of great interest. Several studies have been conducted on fabrication and characterization of polycaprolactone nanocomposite scaffolds, but none of these researches has used mesoporous silica particles (KIT-6). In this project, a high-strength and bioactive nanocomposite scaffold has been developed which consists of polycaprolactone and mesoporous silica particles. Results showed that increase of KIT-6 particles percentages up to 5% leads to the enhancement of tensile strength of scaffold from 1.8 ± 0.2 to 2.9 ± 1.0 MPa. Although wettability of scaffolds in presence of particles was totally lower than pure PCL scaffold, but increase of particles percentages led to enhancement of wettability and water absorption of scaffolds. On the other hand presence of KIT-6 particles increased specific surface area and also bioactivity of scaffold was increased by enhancement of ion exchange between surface and simulated body fluid. Finally it was concluded that PCL-KIT-6 scaffolds are a suitable candidate for application in tissue engineering.

Design and additive manufacturing of flexible polycaprolactone scaffolds with highly-tunable mechanical properties for soft tissue engineering

Additive manufacturing (AM) techniques are widely used to fabricate tissue-engineered scaffolds due to their unique capability in constructing controllable macro/microarchitectures. However, it is still a huge challenge to produce flexible structures with mechanical properties comparable to those of native soft tissues by utilizing AM techniques and clinically-available biodegradable polymers. Here, a novel strategy was developed to design and fabricate flexible polycaprolactone scaffolds with highly-tunable mechanical properties by using sinusoidal filament networks rather than conventional linear filament networks. Selective laser sintering was employed to fabricate morphologically-controlled non-orthogonal scaffolds without the need for additional support structures. Uniaxial compression testing revealed that the elastic modulus of the resultant PCL scaffolds with sinusoidal filament networks can be widely tuned in the range of 1944.0 ± 228.7 kPa to 27.3 ± 12.0 kPa by adjusting the filament period and amplitude-to-period ratio. During periodical compression, the scaffolds experienced a rapid strain-induced softening process within the first 10 cycles of compression. A balanced stage with similar compression responses reached and stably maintained even when the scaffolds were further compressed to 200 times. The presented method might provide a promising approach to design and fabricate various flexible scaffolds with tissue-specific geometry and mechanical properties for soft tissue engineering.

3D-printed poly(Ɛ-caprolactone) scaffold with gradient mechanical properties according to force distribution in the mandible for mandibular bone tissue engineering

In bone tissue engineering, prediction of forces induced to the native bone during normal functioning is important in the design, fabrication, and integration of a scaffold with the host. The aim of this study was to customize the mechanical properties of a layer-by-layer 3D-printed poly(ϵ-caprolactone) (PCL) scaffold estimated by finite element (FE) modeling in order to match the requirements of the defect, to prevent mechanical failure, and ensure optimal integration with the surrounding tissue. Forces and torques induced on the mandibular symphysis during jaw opening and closing were predicted by FE modeling. Based on the predicted forces, homogeneous-structured PCL scaffolds with 3 different void sizes (0.3, 0.6, and 0.9 mm) were designed and 3D-printed using an extrusion based 3D-bioprinter. In addition, 2 gradient-structured scaffolds were designed and 3D-printed. The first gradient scaffold contained 2 regions (0.3 mm and 0.6 mm void size in the upper and lower half, respectively), whereas the second gradient scaffold contained 3 regions (void sizes of 0.3, 0.6, and 0.9 mm in the upper, middle and lower third, respectively). Scaffolds were tested for their compressive and tensile strength in the upper and lower halves. The actual void size of the homogeneous scaffolds with designed void size of 0.3, 0.6, and 0.9 mm was 0.20, 0.59, and 0.95 mm, respectively. FE modeling showed that during opening and closing of the jaw, the highest force induced on the symphysis was a compressive force in the transverse direction. The compressive force was induced throughout the symphyseal line and reduced from top (362.5 N, compressive force) to bottom (107.5 N, tensile force) of the symphysis. Compressive and tensile strength of homogeneous scaffolds decreased by 1.4-fold to 3-fold with increasing scaffold void size. Both gradient scaffolds had higher compressive strength in the upper half (2 region-gradient scaffold: 4.9 MPa; 3 region-gradient scaffold: 4.1 MPa) compared with the lower half (2 region-gradient scaffold: 2.5 MPa; 3 region-gradient scaffold: 2.7 MPa) of the scaffold. 3D-printed PCL scaffolds had higher compressive strength in the scaffold layer-by-layer building direction compared with the side direction, and a very low tensile strength in the scaffold layer-by-layer building direction. Fluid shear stress and fluid pressure distribution in the gradient scaffolds were more homogeneous than in the 0.3 mm void size scaffold and similar to the 0.6 mm and 0.9 mm void size scaffolds. In conclusion, these data show that the mechanical properties of 3D-printed PCL scaffolds can be tailored based on the predicted forces on the mandibular symphysis. These 3D-printed PCL scaffolds had different mechanical properties in scaffold building direction compared with the side direction, which should be taken into account when placing the scaffold in the defect site. Our findings might have implications for improved performance and integration of scaffolds with native tissue.

3D printed PCL scaffold reinforced with continuous biodegradable fiber yarn: A study on mechanical and cell viability properties

In this study, poly (ε‐caprolactone) (PCL) scaffolds were printed and reinforced, simultaneously, with biodegradable poly glycolic acid (PGA) suture yarn, as a continuous reinforcing fiber, in the Fused Deposition Modeling (FDM) 3D printing process. Albeit PCL is a suitable material for biomedical applications, its low mechanical properties, and low degradation rate have limited its usage. A biocompatible suture yarn was used as the reinforcing material to enhance the mechanical properties and biodegradation characteristics, via an innovative method of continuous fiber embedding in the FDM process. The reinforced PCL samples were 3D printed with the setting porosity value of 60% and 0°/60°/120° lay-down pattern. The mechanical and biological properties of the scaffolds were tested to prove the effectiveness of the produced scaffolds for bone substitute purposes. Mechanical properties assessments showed that with a 22 vol.% suture yarn content in the 3D printed PCL scaffolds, the tensile strength, and elastic modulus remarkably increased up to 374% and 775%, respectively. The degradation of the reinforced PCL was 20 times higher than that of the non-reinforced PCL samples, after ten weeks, dominated by the fiber degradation phenomenon. After three days of cell culture, the proliferation assay of the built scaffovd the non-toxicity of the reinforced PCL.