We introduce an enhanced nanoengineered ionic-covalent entanglement (NICE) bioink for the fabrication of mechanically stiff and elastomeric 3D biostructures. NICE bioink formulations combine nanocomposite and ionic-covalent entanglement (ICE) strengthening mechanisms to print customizable cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness. Nanocomposite and ICE strengthening mechanisms complement each other through synergistic interactions, improving mechanical strength, elasticity, toughness, and flow properties beyond the sum of the effects of either reinforcement technique alone. Herschel-Bulkley flow behavior shields encapsulated cells from excessive shear stresses during extrusion. The encapsulated cells readily proliferate and maintain high cell viability over 120 days within the 3D-printed structure, which is vital for long-term tissue regeneration. A unique aspect of the NICE bioink is its ability to print much taller structures, with higher aspect ratios, than can be achieved with conventional bioinks without requiring secondary supports. We envision that NICE bioinks can be used to bioprint complex, large-scale, cell-laden constructs for tissue engineering with high structural fidelity and mechanical stiffness for applications in custom bioprinted scaffolds and tissue engineered implants.

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We investigated the potential use of 3D hybrid membrane: poly (ε-caprolactone) (PCL) mesh using rotary jet spinning with subsequent chitosan (CH) coating. The morphological examinations by scanning electron microscopy (SEM) were proved the efficiency of this technique on obtaining relative homogeneous PCL fiber mats (15,49 ± 4,1µm), with high surface porosity (1,06 ± 0,41µm) and effective CH coating. The feasibility of rotary jet spinning allowed the solvent evaporation during the process; this fact was verified by differential scanning calorimetry (DSC), indeed also had verified changes in thermal properties on the hybrid membrane, since the present of CH. It was investigated the mechanical properties of the hybrid membrane and CH film, the data were that the samples presents good tensile modulus but low strain at the break. In addition, it was verified the biocompatibility properties in vitro using Vero cells. PCL mesh demonstrated cells more spread vastly in the pore surface, with attachments in between fibers indicating the potential for cell adhesion. The films samples (CH and hybrid membrane) resulted in a cells layer on the surfaces with an intense staining (metachromasy), which is the result of cells more active. The cell counting -5 days of culture- and the MTT assay -21 days of culture- demonstrated that the materials tested proved to be different from the positive control and equal to each other and this fact, in our view, this indicates a satisfactory proliferation. Thus, based on the results here, this novel hybrid membrane provides an attractive material for tissue engineering applications.

Bone substitutes are required to repair osseous defects caused by a number of factors, such as traumas, degenerative diseases, and cancer. Autologous bone grafting is typically used to bridge bone defects, but suffers from chronic pain at the donor-site and limited availability of graft material. Tissue engineering approaches are being investigated as viable alternatives, which ideal scaffold should be biocompatible, biodegradable, and promote cellular interactions and tissue development, need to present proper mechanical and physical properties. In this study, poly(ε-caprolactone) (PCL), oleic acid (OA) and hydroxyapatite (HAp) were used to obtain films whose properties were investigated by contact angle, scanning electron microscopy, atomic force microscopy, tensile mechanical tests, and in vitro tests with U2OS human osteosarcoma cells by direct contact. Our results indicate that by using OA as surfactant/dispersant, it was possible to obtain a homogenous film with HAp. The PCL/OA/Hap sample had twice the roughness of the control (PCL) and a lower contact angle, indicating increased hydrophilicity of the film. Furthermore, mechanical testing showed that the addition of HAp decreased the load at yield point and tensile strength and increased tensile modulus, indicating a more brittle composition vs. PCL matrix. Preliminary cell culture experiments carried out with the films demonstrated that U2OS cells adhered and proliferated on all surfaces. The data demonstrate the improved dispersion of HAp using OA and the important consequences of this addition on the composite, unveiling the potentially of this composition for bone growth support. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1076-1082, 2016.

Our hypothesis was to investigate the fatty acid potential as a bone induction factor. In vitro and in vivo studies were performed to evaluate this approach. Oleic acid was used in a 0.5 wt.% concentration. Polycaprolactone was used as the polymeric matrix by combining solvent-casting and particulate-leaching techniques, with a final porosity of 70 wt.%, investigated by SEM images. Contact angle measurements were produced to investigate the influence of oleic acid on polycaprolactone chains. Cell culture was performed using adipocyte-derived stem cells to evaluate biocompatibility and bioactivity properties. In addition, in vivo studies were performed to evaluate the induction potential of oleic acid addition. Adipocyte-derived stem cells were used to provide differentiation after 21 days of culture. Likewise, information were obtained with in vivo data and cellular invagination was observed on both scaffolds (polycaprolactone and polycaprolactone /oleic acid); interestingly, the scaffold with oleic acid addition demonstrated that cellular migrations are not related to the surrounding tissue, indicating bioactive potential. Our hypothesis is that fatty acid may be used as a potential induction factor for bone tissue engineering. The study's findings indicate oleic acid as a possible agent for bone induction, according to data on cell differentiation, proliferation, and migration. Impact statement The biomaterial combined in this study on bone regeneration is innovative and shows promising results in the treatment of bone lesions. Polycaprolactone (PCL) and oleic acid have been studied separately. In this research, we combined biomaterials to assess the stimulus and the speed of bone healing.

Rotary jet spinning (RJS) and electrospinning are techniques to obtain fibrous scaffolds. RJS is a simple method, which fabricates three-dimensional fibers by exploiting a high-speed rotating nozzle, creating a polymer jet which stretches until solidification, and does not require high voltage. In opposite, electrospinning technique needs the presence of an external electric field to create fiber from the polymeric jet solution. This article investigates both processes using two different biocompatible polymers: Poly(L-lactic acid) (PLLA) and Poly(ε-caprolactone) (PCL). Samples were characterized by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimeter, and Fourier-transform infrared spectroscopy. Morphological observations showed the efficiency of both techniques in obtaining nanofibers. Thermal analyses of data indicate immiscible property of different blends and the total solvent evaporation. In vitro cytocompatibility test showed that RJS and electrospinning samples exhibited good cytocompatibility. Based on these results, it may be concluded that the fibers obtained with both technologies are non-cytotoxicity and with good biocompatibility, and might be suitable for applications as scaffold for cell growth.

This study aimed to evaluate in vitro and in vivo polymeric membranes obtained by a rotary jet-spinning process for the repair of critical bone defects in the calvaria of Wistar rats, for future use in tissue engineering. Experimental sample collections were performed on the 30, 60 and 90th postoperative days, and the analyses performed were histomorphometric, immunohistochemistry, and western blotting. Reducing inflammatory infiltrate in all groups and experimental periods, angiogenesis on the 30th day did not show any difference between the groups, on the 60th day, 5% polycaprolactone/beta-tricalcium phosphate(PCL/β-TCP) was high compared to control (C), and on the 90th day, the same group reduced when compared to C and 10% PCL/β-TCP. The fibroplasia presented oscillations in every segment; on the 30th and 60th day, there was an increase in 5% PCL/β-TCP, which decreased by the 90th day compared to group C. 10% PCL/β-TCP decreased compared to C on the 60th and 90th day. The percentage of the collagen area remained high in all groups and all experimental periods. Immunohistochemistry quantifications showed variations in bone metabolism suggesting new bone formation. The 5 and 10% PCL/β-TCP scaffold were promising for the bone regeneration process because they participated in the modulation of inflammation, angiogenesis, fibroplasia, and collagenosis.

Tissue engineering represents a promising alternative for reconstructive surgical procedures especially for the repair of bone defects that do not regenerate spontaneously. The present study aimed to evaluate the effects of the elastin matrix (E24/50 and E96/37) incorporated with hydroxyapatite (HA) or morphogenetic protein (BMP) on the bone repair process in the distal metaphysis of rat femur. The groups were: control group (CG), hydrolyzed elastin matrix at 50˚C/24h (E24/50), E24/50 + HA (E24/50/HA), E24/50 + BMP (E24/50/ BMP), hydrolyzed elastin matrix at 37˚C/96h (E96/37), E96/37 + HA (E96/37/HA), E96/37 + BMP (E96/37/BMP). Macroscopic and radiographic analyses showed longitudinal integrity of the femur in all groups without fractures or bone deformities. Microtomographically, all groups demonstrated partial closure by mineralized tissue except for the E96/37/HA group with hyperdense thin bridge formation interconnecting the edges of the ruptured cortical. Histologically, there was no complete cortical recovery in any group, but partial closure with trabecular bone. In defects filled with biomaterials, no chronic inflammatory response or foreign body type was observed. The mean volume of new bone formed was statistically significant higher in the E96/37/HA and E24/50 groups (71.28 ± 4.26 and 66.40 ± 3.69, respectively) than all the others. In the confocal analysis, it was observed that all groups