RESUMEN
The presented work deals with the photocuring of telechelic macromonomers derived from plant-based fatty acids to obtain a soft polymer network. Compositions were made by mixing macromonomers with three different concentrations (0.5, 1, and 2%) of two type I photoinitiators (Omnirad 2022 and Omnirad 819). All formulations were then subjected to photopolymerization studies by applying UV-assisted differential scanning calorimetry (UV-DSC) measurements at isothermal conditions at 37 °C with a narrow light source wavelength of 365 nm and irradiation (light intensity) of 20 and 50 mW/cm2. The percentage conversions, reaction orders, and constants were estimated based on autocatalytic Sestak-Berggen and Avrami models. In this work, for the first time, the influence of the curing conditions on the photopolymerization process, such as the photoinitiator concentration, light intensity, and oxygen presence/absence, were investigated for these novel systems. The results indicated significant differences between the two commercially available photoinitiators and their effects on photopolymerization kinetics. The maximum reaction rate was found to be considerably higher for Omnirad 2022 (which is a blend of three different compounds), especially at a lower light intensity, i.e., 20 mW/cm2, compared to Omnirad 819. However, it led to lower maximum conversion in an air atmosphere. The dynamic thermomechanical analysis (DMTA) revealed that light intensity, photoinitiator concentration, and oxygen presence had a strong effect on the storage modulus and loss modulus values. It was concluded that the chemical structure of the photoinitiator and curing conditions had a strong effect on the photopolymerization kinetics and properties of the prepared soft polymer networks.
RESUMEN
Injectable and in situ photocurable biomaterials are receiving a lot of attention due to their ease of application via syringe or dedicated applicator and ability to be used in laparoscopic and robotic minimally invasive procedures. The aim of this work was to synthesize photocurable ester-urethane macromonomers using a heterometallic magnesium-titanium catalyst, magnesium-titanium(iv) butoxide for elastomeric polymer networks. The progress of the two-step synthesis of macromonomers was monitored using infrared spectroscopy. The chemical structure and molecular weight of the obtained macromonomers were characterized using nuclear magnetic resonance spectroscopy and gel permeation chromatography. The dynamic viscosity of the obtained macromonomers was evaluated by a rheometer. Next, the photocuring process was studied under both air and argon atmospheres. Both the thermal and dynamic mechanical thermal properties of the photocured soft and elastomeric networks were investigated. Finally, in vitro cytotoxicity screening of polymer networks based on ISO10993-5 revealed high cell viability (over 77%) regardless of curing atmosphere. Overall, our results indicate that this heterometallic magnesium-titanium butoxide catalyst can be an attractive alternative to commonly used homometallic catalysts for the synthesis of injectable and photocurable materials for medical applications.
RESUMEN
Novel advanced biomaterials have recently gained great attention, especially in minimally invasive surgical techniques. By applying sophisticated design and engineering methods, various elastomer-hydrogel systems (EHS) with outstanding performance have been developed in the last decades. These systems composed of elastomers and hydrogels are very attractive due to their high biocompatibility, injectability, controlled porosity and often antimicrobial properties. Moreover, their elastomeric properties and bioadhesiveness are making them suitable for soft tissue engineering. Herein, we present the advances in the current state-of-the-art design principles and strategies for strong interface formation inspired by nature (bio-inspiration), the diverse properties and applications of elastomer-hydrogel systems in different medical fields, in particular, in tissue engineering. The functionalities of these systems, including adhesive properties, injectability, antimicrobial properties and degradability, applicable to tissue engineering will be discussed in a context of future efforts towards the development of advanced biomaterials.