Copolymers of N-(4-bromophenyl)-2-methacrylamide with 2-hydroxyethyl methacrylate

Gamma-Irradiated Gum Arabic Grafted with 2-Hydroxyethyl Methacrylate: A Novel Superabsorbent Polymer for Controlled Folic Acid Release

This study explores the synthesis and characterization of superabsorbent hydrogels derived from chemically modified gum Arabic, designed for controlled folic acid release. The synthesis involves a two-step process: carboxymethylation followed by grafting with 2-hydroxyethyl methacrylate via gamma irradiation. The resulting hydrogels exhibit enhanced mechanical strength and controlled diffusivity, essential for nutrient delivery systems. Key factors such as copolymer composition and irradiation dose are investigated, affecting the synthesis process. Systematic studies of swelling behaviors reveal that the hydrogel achieves a maximum swelling of 888.1% at 40 °C. The hydrogels are loaded with folic acid, and in vitro, sustained release profiles are examined under various pH conditions. The maximum release of 83.3% is observed after 24 h at pH 7.0, following a Korsmeyer-Peppas release mechanism. Different characterization techniques, confirm the successful synthesis and unique properties of the superabsorbent hydrogels. Rheological behavior analysis, scanning electron microscopy, and biocompatibility assessments provide a comprehensive understanding of the hydrogel structures. Gamma irradiation ensures a homogeneous network structure, crucial for optimal swelling behavior and mechanical properties. This research highlights the potential of eco-friendly biopolymer hydrogels in precise drug delivery applications, leveraging the safety and process control benefits of gamma irradiation.

A Green Catechol-Containing Cellulose Nanofibrils-Cross-Linked Adhesive

Traditional adhesives with strong adhesion are widely applied in the fields of wood, building, and electronics. However, the synthesis and usage of commercial adhesives are not eco-friendly, which are harmful to human health and to the environment. In this study, a green cellulose nanofibrils/poly(hydroxyethyl methacrylate-co-dopamine methacrylamide) (CNFs/P(HEMA-co-DMA)) adhesive with excellent biocompatibility and strong bonding strength has been fabricated. P(HEMA-co-DMA) with a catechol content of 7.1 mol % was synthesized using dopamine methacrylamide and hydroxyethyl methacrylate. The CNFs/P(HEMA-co-DMA) adhesive was generated by cross-linking P(HEMA-co-DMA) solution using cellulose nanofibrils (CNFs). Strong adhesion was realized on various substrates, with a maximum lap shear strength of 5.50 MPa on steel. The NIH 3T3 cells test demonstrated that the adhesive possessed excellent biocompatibility. The green catechol-containing CNFs-cross-linked adhesive has promising potential for applications in medicine, electronic, food packaging, and engineering.

Exploiting Wavelength Orthogonality for Successive Photoinduced Polymerization-Induced Self-Assembly and Photo-Crosslinking

We report a facile benchtop process for the synthesis of cross-linked polymeric nanoparticles by exploiting wavelength-selective photochemistry to perform orthogonal photoinduced polymerization-induced self-assembly (Photo-PISA) and photo-crosslinking processes. We first established that the water-soluble photocatalyst, zinc meso-tetra(N-methyl-4-pyridyl) porphine tetrachloride (ZnTMPyP) could activate the aqueous PET-RAFT dispersion polymerization of hydroxypropyl methacrylate (HPMA). This photo-PISA process could be conducted under low energy red light (λ_max = 595 nm, 10.2 mW/cm²) and without deoxygenation due to the action of the singlet oxygen quencher, biotin (vitamin B₇), which allowed for the synthesis of a range of nanoparticle morphologies (spheres, worms, and vesicles) directly in 96-well plates. To perform wavelength selective nanoparticle cross-linking, we added the photoresponsive monomer, 7-[4-(trifluoromethyl)coumarin] methacrylamide (TCMAm) as a comonomer without inhibiting the evolution of the nanoparticle morphology. Importantly, under red light, exclusive activation of the photo-PISA process occurs, with no evidence of TCMAm dimerization under these conditions. Subsequent switching to a UV source (λ_max = 365 nm, 10.2 mW/cm²) resulted in rapid cross-linking of the polymer chains, allowing for retention of the nanoparticle morphology in organic solvents. This facile synthesis of cross-linked spheres, worms, and vesicles demonstrates the utility of orthogonal light-mediated chemistry for performing decoupled wavelength selective chemical processes.

Injectable Stem Cell Laden Open Porous Microgels That Favor Adipogenesis: In Vitro and in Vivo Evaluation

Microgels, with large surface area per volume, show great advantages in adipose tissue engineering due to their injectability and similarity with natural extracellular matrix. However, to date, no studies have tried applying microgels to adipose tissue regeneration. Herein, based on double-bonded poly(l-glutamic acid)-g-2-hydroxyethyl methacrylate (PLGA-g-HEMA) and maleic anhydride-modified chitosan (MCS), an open porous microgel with high hydrophilicity and great injectability is successfully prepared (microgels diameters of 200-300 μm, pore diameter of 38 μm, and porosity of 88.3%). The storage modulus of 30 mg/mL of the microgel dispersions is 2000 Pa, which is similar to that of the native adipose tissue. The spheroidal stem cell shape and extensive cell-cell connections can be formed in the present microgels to promote adipogenic differentiation and realize adipose tissue regeneration. After injection in vitro, the microgels can maintain high stem cell viability up to 14 days. The extensive Oil red O staining is observed after adipogenic induction for 14 days. After 12 weeks postimplantation, adipose tissues can be regenerated well. Blood vessels are formed in the neogenerated tissues. The degradation rate of microgels roughly matches with the adipose tissue formation rate. The study offers an applicable microgel system to boost the adipose tissue regeneration.