Synthetic polyester elastomeric constructs have become increasingly important for a range of healthcare applications, due to tunable soft elastic properties that mimic those of human tissues. A number of these constructs require intricate mechanic design to achieve a tunable material with controllable curing. Here, we present the synthesis and characterization of poly(itaconate-co-citrateco-octanediol) (PICO), which exhibits tunable formation of elastomeric networks through radical crosslinking of itaconate in the polymer backbone of viscous polyester gels. Through variation of reaction times and monomer molar composition, we were able to generate materials with modulation of a wide range of elasticity (36-1476 kPa), indicating the tunability of materials to specific elastomeric constructs. This correlated with measured rapid and controllable gelation times. As a proof-of-principle, we developed scaffold support for cardiac tissue patches, which presented visible tissue organization and viability with appropriate elastomeric support from PICO materials. These formulations present potential application in a range of healthcare applications with requirement for elastomeric support with controllable, rapid gelation under mild conditions.

Bioelastomers have been extensively used in tissue engineering applications because of favorable mechanical stability, tunable properties, and chemical versatility. As these materials generally possess low elastic modulus and relatively long gelation time, it is challenging to 3D print them using traditional techniques. Instead, the field of 3D printing has focused preferentially on hydrogels and rigid polyester materials. To develop a versatile approach for 3D printing of elastomers, we used freeform reversible embedding of suspended prepolymers. A family of novel fast photocrosslinakble bioelastomer prepolymers were synthesized from dimethyl itaconate, 1,8-octanediol, and triethyl citrate. Tensile testing confirmed their elastic properties with Young’s moduli in the range of 11–53 kPa. These materials supported cultivation of viable cells and enabled adhesion and proliferation of human umbilical vein endothelial cells. Tubular structures were created by embedding the 3D printed microtubes within a secondary hydrogel that served as a temporary support. Upon photocrosslinking and porogen leaching, the polymers were permeable to small molecules (TRITC-dextran). The polymer microtubes were assembled on the 96-well plates custom made by hot-embossing, as a tool to connect multiple organs-on-a-chip. The endothelialization of the tubes was performed to confirm that these microtubes can be utilized as vascular tubes to support parenchymal tissues seeded on them.

Polymer flooding is a well-established chemical enhanced oil recovery (EOR) technique. However, its application to High-Temperature and High-Salinity (HTHS) carbonate reservoirs remains a challenging task due to the unavailability of polymers that can withstand the harsh conditions. Identifying thermally stable, salt-tolerant polymers with high thickening efficiency and low adsorption in carbonate reservoirs will be a major step towards the successful application of polymer flooding in HTHS carbonate reservoirs. The potential biopolymer "Schizophyllan" is identified and its rheological properties are investigated. The effect of temperature and salinity on the behavior of the polymer solution is analyzed. In addition, the mechanical and long-term thermal stability of the polymer solutions and their adsorption on synthetic carbonate cores are also discussed. The tested polymer showed temperature stability and salt tolerance with no decrease in viscosity up to a temperature of 135 °C and 220 g/L salinity. The thermal stability and salt tolerance of the biopolymer are attributed to the non-ionic nature and the triple helical structure. Moreover, the polymer solution showed no decrease in viscosity when kept at 120 °C under anaerobic conditions for over eight months. A series of coreflooding experiments have been performed at reservoir temperature (120 °C) and salinity (167 g/L) to evaluate the performance of the polymer EOR process in carbonate reservoirs. Various parameters including reservoir permeability, polymer slug size and the initiation time of polymer EOR process are varied in this study in order to determine the optimum flooding conditions. Dynamic adsorption of the polymer on rock surface is also quantified and found to be very low in magnitude. Coreflooding results of polymer EOR using the potential biopolymer offered encouraging results with a range of incremental recoverable oil between 7-10% after waterflooding. Further research is still required on application of biopolymers on reservoir cores.

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