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Poly(ethylene terephthalate) (PET) is known for its various useful characteristics, including its applicability in cardiovascular applications, more precisely as synthetic bypass grafts for large diameter (≥ 6 mm) blood vessels. Although it is widely used, PET is not an optimal material as it is not interactive with endothelial cells, which is required for bypasses to form a complete endothelium. Therefore, in this study, poly(alkylene terephthalate)s (PATs) have been studied. They were synthesized via a single-step solution polycondensation reaction, which requires mild reaction conditions and avoids the use of a catalyst or additives like heat stabilizers. A homologous series was realized in which the alkyl chain length varied from 5 to 12 methylene groups (n = 5–12). Molar masses up to 28,000 g/mol were obtained, while various odd-even trends were observed with modulated differential scanning calorimetry (mDSC) and rapid heat-cool calorimetry (RHC) to access the thermal properties within the homologous series. The synthesized PATs have been subjected to in vitro cell viability assays using Human Umbilical Vein Endothelial Cells (HUVECs) and Human Dermal Microvascular Endothelial Cells (HDMECs). The results showed that HUVECs adhere and proliferate most pronounced onto PAT(n=9) surfaces, which could be attributed to the surface roughness and morphology as determined by atomic force microscopy (AFM) (i.e. Rq = 204.7 nm). HDMECs were investigated in the context of small diameter vessels and showed superior adhesion and proliferation after seeding onto PAT(n=6) substrates. These preliminary results already pave the way towards the use of PAT materials as substrates to support endothelial cell adhesion and growth. Indeed, as superior endothelial cell interactivity compared to PET was observed, time-consuming and costly surface modifications of PET grafts could be avoided by exploiting this novel material class.Poly(ethylene terephthalate) (PET) is known for its various useful characteristics, including its applicability in cardiovascular applications, more precisely as synthetic bypass grafts for large diameter (≥ 6 mm) blood vessels. Although it is widely used, PET is not an optimal material as it is not interactive with endothelial cells, which is required for bypasses to form a complete endothelium. Therefore, in this study, poly(alkylene terephthalate)s (PATs) have been studied. They were synthesized via a single-step solution polycondensation reaction, which requires mild reaction conditions and avoids the use of a catalyst or additives like heat stabilizers. A homologous series was realized in which the alkyl chain length varied from 5 to 12 methylene groups (n = 5–12). Molar masses up to 28,000 g/mol were obtained, while various odd-even trends were observed with modulated differential scanning calorimetry (mDSC) and rapid heat-cool calorimetry (RHC) to access the thermal properties within the homologous series. The synthesized PATs have been subjected to in vitro cell viability assays using Human Umbilical VeinEndothelial Cells (HUVECs) and Human Dermal Microvascular Endothelial Cells (HDMECs). The results showed that HUVECs adhere and proliferate most pronounced onto PAT(n=9) surfaces, which could be attributed to the surface roughness and morphology as determined by atomic force microscopy (AFM) (i.e. Rq = 204.7 nm). HDMECs were investigated in the context of small diameter vessels and showed superior adhesion and proliferation after seeding onto PAT(n=6) substrates. These preliminary results already pave the way towards the use of PAT materials as substrates to support endothelial cell adhesion and growth. Indeed, as superior endothelial cell interactivity compared to PET was observed, time-consuming and costly surface modifications of PET grafts could be avoided by exploiting this novel material class.

This research aims at developing a more potent solution for deep flexor tendon repair by combining a mechanical and biological approach. A reinforced, multi-layered electrospun tubular construct is developed, composed of three layers: an inner electrospun layer containing an anti-inflammatory component (Naproxen), a middle layer of braided monofilament as reinforcement and an outer electrospun layer containing an anti-adhesion component (hyaluronic acid, HA). In a first step, a novel acrylate endcapped urethane-based precursor (AUP) is developed and characterized by measuring molar mass, acrylate content and thermo-stability. The AUP material is benchmarked against commercially available poly(ε-caprolactone) (PCL). Next, the materials are processed into multi-layered, tubular constructs with bio-active components (Naproxen and HA) using electrospinning. In vitro assays using human fibroblasts show that incorporation of the bio-active components is successful and not-cytotoxic. Moreover, tensile testing using ex vivo sheep tendons prove that the developed multi-layered constructs fulfill the required strength for tendon repair (i.e. 2.79-3.98 MPa), with an ultimate strength of 8.56 ± 1.92 MPa and 8.36 ± 0.57 MPa for PCL and AUP/PCL constructs respectively. In conclusion, by combining a mechanical approach (improved mechanical properties) with the incorporation of bio-active compounds (biological approach), this solution shows its potential for application in deep flexor tendon repair. ispartof: Materials Science and Engineering: C vol:119 ispartof: location:Netherlands status: Published online

Current soft tissue repair techniques for women with breast cancer remain associated with several drawbacks including surgical complications and a high resorption rate for lipofilling techniques. Hence, the need to develop improved adipose tissue reconstruction strategies. Additive manufacturing can be a promising tool towards the development of patient-specific scaffolds which are able to support adipose tissue engineering. In the present work, scaffolds composed of both methacrylamide-modified gelatin (Gel-MA) and methacrylated kappa-carrageenan (Car-MA), i.e. hydrogel blends, were developed using extrusion-based 3D printing in order to establish a close resemblance to the native extracellular matrix. The hydrogel blends were benchmarked to scaffolds constituting of only Gel-MA. Our results indicate that both types of scaffolds remain stable over time (21 days), are able to absorb large amounts of water and exhibit mechanical properties comparable to those of native breast tissue (2 kPa). Furthermore, a similar cell viability (> 90%) and proliferation rate after 14 days was obtained for adipose tissue-derived stem cells (ASCs) upon seeding onto both types of scaffolds. Additionally, the ASCs were able to differentiate into the adipogenic lineage on the hydrogel blend scaffolds, although their differentiation potential was lower compared to that of ASCs seeded onto the Gel-MA scaffolds. (C) 2019 Elsevier B.V. All rights reserved.

Hypothesis The complete removal of remaining polymer debris after stripping of optical fiber cables is essential for high precision connection between two fibers. It can be anticipated that electrospun porous membranes as cleaning wipes are able to trap and retain polymer debris within their pores. Impregnation of an oil-in-water emulsion as cleaning agent lowers the interfacial tension between debris and the optical fiber thereby enabling the straightforward removal of polymer debris from the optical fiber. Experiments Electrospun membranes of poly(ethylene terephthalate) (PET) and cellulose acetate (CA) were obtained with fiber diameters of 0.430 μm and 2 μm respectively. The oil-in-water emulsion was formulated with 10 wt% medium chain triglyceride (MCT) and 10 wt% Tween 80 surfactant in an aqueous phosphate buffer solution. Findings In a scoring range from 0 to 5 for which the score 0 indicated superior cleaning and the score 5 referred to the least efficient cleaning, the electrospun fiber mats (without emulsion) scored within the range of 2–4 while emulsion impregnated electrospun fiber mats revealed the best score of 0. A drastic improvement was thus clearly evident from the obtained results when the cleaning emulsion was applied. The materials developed herein thus represent a new class of soft cleaning agents for optical fibers.

Gelatin nanofibrous structures, characterized by high specific surface area and high porosity, have been widely researched for biomedical and food applications. The present paper researches the potential of electrospinning to produce a nanofibrous cold-gelling (or instant) gelatin product. Our results show that gelatin nanofibers are cold-water-soluble due to their high surface-to-volume ratio, facilitating easy water penetration and dissolution, and this for several gelatin types. Additionally, fast gelation after dissolution in cold water indicates that the electrospinning process does not significantly reduce the gelatin molecular weight, nor compromise triple helix formation. These conclusions were supported by thorough investigation of the internal gelatin structure, using a new approach based on modulated temperature scanning calorimetry. Oscillation rheology revealed that the nanofiber-based gels have moduli comparable to powder-based gels. Gelatin nanofibers can thus be used as instant gelatin product, without the drawbacks of traditional amorphous instant gelatins such as sensitivity to moisture, low wettability and low modulus of the cold gel. Using the approach reported here, every electrospinnable, but non-cold-water-soluble gelatin can be transformed into a cold-water-soluble variant, regardless of the type or modification. Electrospinning can thus offer enormous flexibility in materials selection, enabling the production of cold gels loaded with temperature-sensitive components, UV-cross-linkable cold gels, etc. (C) 2016 Elsevier Ltd. All rights reserved.