Twin screw extrusion of conductive citrate-based biomaterials

Elastomeric Polyesters in Cardiovascular Tissue Engineering and Organs-on-a-Chip

Cardiovascular tissue constructs provide unique design requirements due to their functional responses to substrate mechanical properties and cyclic stretching behavior of cardiac tissue that requires the use of durable elastic materials. Given the diversity of polyester synthesis approaches, an opportunity exists to develop a new class of biocompatible, elastic, and immunomodulatory cardiovascular polymers. Furthermore, elastomeric polyester materials have the capability to provide tailored biomechanical synergy with native tissue and hence reduce inflammatory response in vivo and better support tissue maturation in vitro. In this review, we highlight underlying chemistry and design strategies of polyester elastomers optimized for cardiac tissue scaffolds. The major advantages of these materials such as their tunable elasticity, desirable biodegradation, and potential for incorporation of bioactive compounds are further expanded. Unique fabrication methods using polyester materials such as micromolding, 3D stamping, electrospinning, laser ablation, and 3D printing are discussed. Moreover, applications of these biomaterials in cardiovascular organ-on-a-chip devices and patches are analyzed. Finally, we outline unaddressed challenges in the field that need further study to enable the impactful translation of soft polyesters to clinical applications.

3D Printability Assessment of Poly(octamethylene maleate (anhydride) citrate) and Poly(ethylene glycol) Diacrylate Copolymers for Biomedical Applications

Herein, we present the first example of 3D printing with poly(octamethylene maleate (anhydride) citrate) (POMaC), a bio-adhesive material which has shown particular promise for implantable biomedical devices. The current methods to fabricate such devices made from POMaC are hindered by the imposed constraints of designing complex molds. We demonstrate the feasibility of exploiting additive manufacturing to 3D print structural functional materials consisting of POMaC. We present 3D printing of biomaterial copolymers consisting of mixtures of poly(ethylene glycol) diacrylate (PEGDA) and POMaC at different ratios. The required parameters were optimized, and characterization of the printing fidelity and physical properties was performed. We have also demonstrated that a range of mechanical properties can be achieved by tuning the POMaC/PEGDA ratio. The biocompatibility of the copolymers was ascertained via a cell viability assay. Such tunable 3D printed biomaterials consisting of POMaC and PEGDA will have significant potential application in the development of functional biomaterial tissue scaffolds and biomedical devices for the future of personalized medicine.

Catalyst-Free Crosslinking Modification of Nata-de-Coco-Based Bacterial Cellulose Nanofibres Using Citric Acid for Biomedical Applications

Bacterial cellulose (BC) has gained attention among researchers in materials science and bio-medicine due to its fascinating properties. However, BC’s fibre collapse phenomenon (i.e., its inability to reabsorb water after dehydration) is one of the drawbacks that limit its potential. To overcome this, a catalyst-free thermal crosslinking reaction was employed to modify BC using citric acid (CA) without compromising its biocompatibility. FTIR, XRD, SEM/EDX, TGA, and tensile analysis were carried out to evaluate the properties of the modified BC (MBC). The results confirm the fibre crosslinking phenomenon and the improvement of some properties that could be advantageous for various applications. The modified nanofibre displayed an improved crystallinity and thermal stability with increased water absorption/swelling and tensile modulus. The MBC reported here can be used for wound dressings and tissue scaffolding.