Abstract Tissue adhesives are widely used for postoperative wound closure and sealing. However, challenges remain regarding adhesive strength, swelling behavior, and biocompatibility. We previously developed tissue adhesives composed of hydrophobically-modified Alaska pollock gelatin and pentaerythritol poly(ethylene glycol) ether tetrasuccinimidyl glutarate (4S-PEG), which demonstrated excellent adhesive strength and biocompatibility. However, the effects of adhesive parameters, such as the molecular weight of 4S-PEG and the degree of hydrophobic modification, on the adhesive characteristics have not yet been determined. In this study, we investigated the effects of the 4S-PEG molecular weight and degree of decanoyl modification on the physicochemical and biological properties of C10-ApGltn/4S-PEG adhesive, including swelling behavior, mechanical strength, burst strength, and biocompatibility. The swelling ratio, tensile strength, and tensile strain of the hydrogels increased with increasing 4S-PEG molecular weight. In contrast, the burst strength increased up to 23 mol% and then decreased. 23C10-ApGltn/4S-PEG10k exhibited biodegradability without inducing severe inflammation and demonstrated excellent physicochemical and biological properties, indicating its suitability for cardiovascular applications.

Abstract Two oligomers and three polymers with diamondoid side groups were prepared by the insertion polymerization of N-octenyladamantane and -diamantane, as well as by polymer-analogous reactions. The molecules consist exclusively of carbon and hydrogen atoms and one secondary amino group per repeating unit. Depending on the charge state (neutral or protonated), the glass transition temperature of the oligomers can be tailored between -30 and approximately 70 °C. We assume that the presence of bulky substituents and amino groups is responsible for the low degree of polymerization (DP) achieved in insertion polymerization. This limitation was circumvented by using commercially available poly(vinylbenzyl chloride) and subsequent polymer-analogous reactions with corresponding aminodiamondoids. The resulting polymers exhibited a nearly quantitative degree of functionalization (DoF), which was determined by NMR (Nuclear Magnetic Resonance) spectroscopy and largely confirmed by elemental analysis and thermogravimetry. All the materials exhibit high thermal stability up to 200 °C or 250 °C. The higher homolog diamantane displays a higher DP and higher yields in functionalization reactions than the corresponding adamantane derivatives do.

Abstract Ionotropic hydrogels, formed through reversible coordination between multivalent metal ions and chelating ligands, represent a promising class of injectable biomaterials that allow for minimally invasive implantation in the body, the encapsulation of unstable biomolecules without loss of biological activity and the fabrication of well-defined three-dimensional objects via extrusion 3D printing. In this study, we report a novel ionotropically gelling polymer containing bisphosphonate groups. The polymers were synthesized from alendronate acrylamide via free radical polymerization. Upon the addition of Ca 2+ and Zn 2+ ions, the polymers formed hydrogels with tunable mechanical properties with higher polymer concentrations, resulting in stiffer hydrogels. Notably, hydrogels with a polymer concentration of 2.5 wt% exhibited a high shear storage modulus of approximately 140 kPa, indicating significant mechanical strength. The hydrogels showed self-healing and stress-thinning behaviors, which are typical of systems crosslinked via dynamic bonds. In addition, hydrogel nanoparticles were fabricated by crosslinking the polymers with Zn²⁺ ions within water-in-oil emulsions. These findings highlight bisphosphonate-bearing polymers as promising ionotropically gelling biomaterials for biomedical applications such as tissue engineering and drug delivery.