Different methods of synthesizing poly(glycerol sebacate) (PGS): A review

Toward a Better Understanding of the Poly(glycerol sebacate)-Water Interface

Molecular simulations were conducted to provide a better description of the poly(glycerol sebacate) (PGS)-water interface. The density and the glass-transition temperature as well as their dependencies on the degree of esterification were examined in close connection with the available experimental data. The work of adhesion and water contact angle were calculated as a function of the degree of esterification. A direct correlation was established between the strength of the hydrogen bond network in the interfacial region and the change in the water contact angle with respect to the degree of esterification. The interfacial region was described by local density profiles and orientations of the water molecules.

Advancements in tissue engineering for cardiovascular health: a biomedical engineering perspective

Myocardial infarction (MI) stands as a prominent contributor to global cardiovascular disease (CVD) mortality rates. Acute MI (AMI) can result in the loss of a large number of cardiomyocytes (CMs), which the adult heart struggles to replenish due to its limited regenerative capacity. Consequently, this deficit in CMs often precipitates severe complications such as heart failure (HF), with whole heart transplantation remaining the sole definitive treatment option, albeit constrained by inherent limitations. In response to these challenges, the integration of bio-functional materials within cardiac tissue engineering has emerged as a groundbreaking approach with significant potential for cardiac tissue replacement. Bioengineering strategies entail fortifying or substituting biological tissues through the orchestrated interplay of cells, engineering methodologies, and innovative materials. Biomaterial scaffolds, crucial in this paradigm, provide the essential microenvironment conducive to the assembly of functional cardiac tissue by encapsulating contracting cells. Indeed, the field of cardiac tissue engineering has witnessed remarkable strides, largely owing to the application of biomaterial scaffolds. However, inherent complexities persist, necessitating further exploration and innovation. This review delves into the pivotal role of biomaterial scaffolds in cardiac tissue engineering, shedding light on their utilization, challenges encountered, and promising avenues for future advancement. By critically examining the current landscape, we aim to catalyze progress toward more effective solutions for cardiac tissue regeneration and ultimately, improved outcomes for patients grappling with cardiovascular ailments.

Evolution of Hybrid Hydrogels: Next-Generation Biomaterials for Drug Delivery and Tissue Engineering

Hydrogels, being hydrophilic polymer networks capable of absorbing and retaining aqueous fluids, hold significant promise in biomedical applications owing to their high water content, permeability, and structural similarity to the extracellular matrix. Recent chemical advancements have bolstered their versatility, facilitating the integration of the molecules guiding cellular activities and enabling their controlled activation under time constraints. However, conventional synthetic hydrogels suffer from inherent weaknesses such as heterogeneity and network imperfections, which adversely affect their mechanical properties, diffusion rates, and biological activity. In response to these challenges, hybrid hydrogels have emerged, aiming to enhance their strength, drug release efficiency, and therapeutic effectiveness. These hybrid hydrogels, featuring improved formulations, are tailored for controlled drug release and tissue regeneration across both soft and hard tissues. The scientific community has increasingly recognized the versatile characteristics of hybrid hydrogels, particularly in the biomedical sector. This comprehensive review delves into recent advancements in hybrid hydrogel systems, covering the diverse types, modification strategies, and the integration of nano/microstructures. The discussion includes innovative fabrication techniques such as click reactions, 3D printing, and photopatterning alongside the elucidation of the release mechanisms of bioactive molecules. By addressing challenges, the review underscores diverse biomedical applications and envisages a promising future for hybrid hydrogels across various domains in the biomedical field.

Biomechanical and Biological Assessment of Polyglycelrolsebacate-Coupled Implant with Shape Memory Effect for Treating Osteoporotic Fractures

Poly(glycerol sebacate) is a biocompatible elastomer that has gained increasing attention as a potential biomaterial for tissue engineering applications. In particular, PGS is capable of providing shape memory effects and allows for a free form, which can remember the original shape and obtain a temporary shape under melting point and then can recover its original shape at body temperature. Because these properties can easily produce customized shapes, PGS is being coupled with implants to offer improved fixation and maintenance of implants for fractures of osteoporosis bone. Herein, this study fabricated the OP implant with a PGS membrane and investigated the potential of this coupling. Material properties were characterized and compared with various PGS membranes to assess features such as control of curing temperature, curing time, and washing time. Based on the ISO 10993-5 standard, in vitro cell culture studies with C2C12 cells confirmed that the OP implant coupled with PGS membrane showed biocompatibility and biomechanical experiments indicated significantly increased pullout strength and maintenance. It is believed that this multifunctional OP implant will be useful for bone tissue engineering applications.

Fabrication of versatile poly(xylitol sebacate)-co-poly(ethylene glycol) hydrogels through multifunctional crosslinkers and dynamic bonds for wound healing

Poly(polyol sebacate) (PPS) polymer family has been recognized as promising biomaterials for biomedical applications with their characteristics of easy production, elasticity, biodegradation, and cytocompatibility. Poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-PEG) has been developed to fabricate PPS-based hydrogels; however, current PXS-co-PEG hydrogels presented limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. Here, we fabricate a new type of PXS-co-PEG hydrogels through the use of multifunctional crosslinkers as well as dynamic bonds. In our design, polyethyleneimine-polydopamine (PEI-PDA) macromers are utilized to crosslink aldehyde-functionalized PXS-co-PEG (APP) through imine bonds and hydrogen bonds. PEI-PDA/APP hydrogels present multiple functional properties (e.g., fluorescent, elastomeric, biodegradable, self-healing, bioadhesive, antioxidant, and antibacterial behaviors). These properties of PEI-PDA/APP hydrogels can be fine-tuned by changing the PDA grafting degrees in the PEI-PDA crosslinkers. Most importantly, PEI-PDA/APP hydrogels are considered promising wound dressings to promote tissue remodeling and prevent bacterial infection in vivo. Taken together, PEI-PDA/APP hydrogels have been demonstrated as versatile biomaterials to provide multiple tailorable properties and desirable functions to expand the utility of PPS-based hydrogels for advanced biomedical applications. STATEMENT OF SIGNIFICANCE: Various strategies have been developed to fabricate poly(polyol sebacate) (PPS)-based hydrogels. However, current PPS-based hydrogels present limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. This work describes that co-engineering crosslinkers and interfacial crosslinking is a promising approach to synthesizing a new type of poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-PEG) hydrogels as multifunctional hydrogels to expand the utility of PPS-based hydrogels for advanced biomedical applications. The fabricated hydrogels present multiple functional properties (e.g., fluorescent, biodegradable, elastomeric, self-healing, bioadhesive, antioxidative, and antibacterial), and these properties can be fine-tuned by the defined crosslinkers. The fabricated hydrogels are also used as promising wound dressing biomaterials to exhibit promoted tissue remodeling and prevent bacterial infection in vivo.

Synthesis of Prepolymers of Poly(glycerol-co-diacids) Based on Sebacic and Succinic Acid Mixtures

In this study, poly(glycerol-co-diacids) prepolymers were produced using different ratios of glycerol (G), sebacic acid (S), and succinic acid (Su) (molar ratios: GS 1:1, GSSu 1:0.9:0.1, GSSu 1:0.8:0.2, GSSu 1:0.5:0.5, GSSu 1:0.2:0.8, GSSu 1:0.1:0.9, GSu 1:1). All polycondensation reactions were performed at 150 °C until reaching a degree of polymerization of ≈55%, inferred by the water volume collected from a reactor. We concluded that the reaction time is correlated with the ratio of diacids used, that is, the increase in succinic acid is proportional to a decrease in the duration of the reaction. In fact, the reaction of poly(glycerol sebacate) (PGS 1:1) is twice as slow as the reaction of poly(glycerol succinate) (PGSu 1:1). The obtained prepolymers were analyzed by electrospray ionization mass spectrometry (ESI-MS) and ¹H and ¹³C nuclear magnetic resonance (NMR). Besides its catalytic influence in poly(glycerol)/ether bond formation, the presence of succinic acid also contributes to a mass growth of ester oligomers, the formation of cyclic structures, a greater number of oligomers detected, and a difference in mass distribution. When compared with PGS (1:1), and even at lower ratios, the prepolymers produced with succinic acid presented mass peak characteristics of oligomer species with a glycerol unit as its end group in higher abundance. Generally, the most abundant oligomers have molecular weights between 400 and 800 g/mol.