Modeling of the Degradation of Poly(ethylene glycol)-co-(lactic acid)-dimethacrylate Hydrogels

Polybasic nanogels for intracellular co-delivery of paclitaxel and carboplatin: a novel approach to ovarian cancer therapy

Ovarian cancer is one of the leading causes of cancer-related deaths in women, with limited progress in treatments despite decades of research. Common treatment protocols rely on surgical removal of tumors and chemotherapy drugs, such as paclitaxel and carboplatin, which are capable of reaching cancer cells throughout the body. However, the effectiveness of these drugs is often limited due to toxic reactions in patients, nonspecific drug distribution affecting healthy cells, and the development of treatment resistance. In this study, we introduce a polybasic nanogel system composed of poly(diethylaminoethyl methacrylate-co-cyclohexyl methacrylate)-g-poly(ethylene glycol) designed for the targeted co-delivery of paclitaxel and carboplatin directly to ovarian cancer cells. These nanogel systems can respond to the cellular microenvironment to achieve controlled, on-demand drug release, reducing off-target effects and enhancing therapeutic uptake. Additionally, we investigated nanoparticle degradation and controlled drug release as a function of various crosslinkers, including tetraethylene glycol dimethacrylate, bis(2-methacryloyl)oxyethyl disulfide, poly(lactic acid)-b-poly(ethylene glycol)-b-poly(lactic acid)dimethacrylate, and polycaprolactone dimethacrylate. Our results, using OVCAR-3 human ovarian cancer cells, demonstrated that this dual-delivery system outperformed free drugs in inducing cancer cell death, representing a promising advance in the field of nanoparticle-based therapies for ovarian cancer. By loading two chemotherapeutic agents into a single, environmentally responsive particle, this approach shows the potential to overcome common resistance mechanisms and achieve more effective tumor suppression. In summary, by delivering chemotherapy more precisely, it may be possible to enhance therapeutic outcomes while minimizing toxicity and nonspecific drug distribution, ultimately improving patient quality of life.

Mechanisms of hydrogel-based microRNA delivery systems and its application strategies in targeting inflammatory diseases

Hydrogels, composed of three-dimensional polymer networks, are excellent delivery carriers and have been extensively employed in the biomedical field. Inflammation acts as a protective mechanism to prevent harmful substances from entering living organisms, but chronic, long-lasting inflammation can cause oxidative stress, which damages tissue and organs and adversely affects patients' quality of life. The aberrant expression of microRNAs (miRNAs) has been found to play a significant part in the etiology and progression of inflammatory diseases, as suggested by growing evidence. Numerous hydrogels that can act as gene carriers for the intracellular delivery of miRNA have been described during ongoing research into innovative hydrogel materials. MiRNA hydrogel delivery systems, which are loaded with exogenous miRNA inhibitors or mimics, enable targeted miRNA intervention in inflammatory diseases and effectively prevent environmental stressors from degrading or inactivating miRNA. In this review, we summarize the classification of miRNA hydrogel delivery systems, the basic strategies and mechanisms for loading miRNAs into hydrogels, highlight the biomedical applications of miRNA hydrogel delivery systems in inflammatory diseases, and share our viewpoints on potential opportunities and challenges in the promising region of miRNA delivery systems. These findings may provide a new theoretical basis for the prevention and treatment of inflammation-related diseases and lay the foundation for clinical translation.

Degradable Poly(Methyl Methacrylate)-co-Methacrylic Acid Nanoparticles for Controlled Delivery of Growth Factors for Bone Regeneration

Bone tissue engineering strategies have been developed to address the limitations of the current gold standard treatment options for bone-related disorders. These systems consist of an engineered scaffold that mimics the extracellular matrix and provides an architecture to guide the natural bone regeneration process, and incorporated growth factors that enhance cell recruitment and ingress into the scaffold and promote the osteogenic differentiation of stem cells and angiogenesis. In particular, the osteogenic growth factor bone morphogenetic protein 2 (BMP-2) has been widely studied as a potent agent to improve bone regeneration. A key challenge in growth factor delivery is that the growth factors must reach their target sites without losing bioactivity and remain in the location for an extended period to effectively aid in the formation of new bone. Protein incorporation into nanoparticles can both protect protein bioactivity and enable its sustained release. In this study, a poly(methyl methacrylate-co-methacrylic acid) nanoparticle-based system was synthesized incorporating a custom poly(ethylene glycol) dimethacrylate crosslinker. It was demonstrated that the nanoparticle degradation rate can be controlled by tuning the number of hydrolytically degradable ester units along the crosslinker. We also showed that the nanoparticles had high affinity for a model protein for BMP-2, and optimal conditions for maximum protein loading efficiency were elucidated. Ultimately, the proposed system and its high degree of tunability can be applied to a wide range of growth factors and tissue engineering applications. Impact Statement In this study, we developed a novel method of synthesizing nanoparticles with tunable degradation rates through the incorporation of a custom synthesized, hydrolytically degradable crosslinker. In addition, we demonstrated the affinity of the synthesized nanoparticles for a model protein for bone morphogenetic protein 2 (BMP-2). The tunability of these nanoparticles can be used to develop complex tissue engineering systems, for example, for the delivery of multiple growth factors involved at different stages of the bone regeneration process.

Hydrogel scaffolds for tissue engineering: the importance of polymer choice

We explore the design and synthesis of hydrogel scaffolds for tissue engineering from the perspective of the underlying polymer chemistry. The key polymers, properties and architectures used, and their effect on tissue growth are discussed.

Percolation of sites not removed by a random walker in d dimensions

How does removal of sites by a random walk lead to blockage of percolation? To study this problem of correlated site percolation, we consider a random walk (RW) of N=uL^{d} steps on a d-dimensional hypercubic lattice of size L^{d} (with periodic boundaries). We systematically explore dependence of the probability Π_{d}(L,u) of percolation (existence of a spanning cluster) of sites not removed by the RW on L and u. The concentration of unvisited sites decays exponentially with increasing u, while the visited sites are highly correlated-their correlations decaying with the distance r as 1/r^{d-2} (in d>2). On increasing L, the percolation probability Π_{d}(L,u) approaches a step function, jumping from 1 to 0 when u crosses a percolation threshold u_{c} that is close to 3 for all 3≤d≤6. Within numerical accuracy, the correlation length associated with percolation diverges with exponents consistent with ν=2/(d-2). There is no percolation threshold at the lower critical dimension of d=2, with the percolation probability approaching a smooth function Π_{2}(∞,u)>0.

Kinetic study of TBD catalyzed δ-valerolactone polymerization using a gas-driven droplet flow reactor

The reaction kinetics of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) catalyzed δ-valerolactone polymerization was determined using a gas-driven droplet reactor.