Inspired by marine mussel adhesive proteins, polymers with catechol side groups have been extensively explored in industrial and academic research. Here, Pluronic L-31 alcoholate ions were used as the initiator to prepare a series of polypeptide-Pluronic-polypeptide triblock copolymers via ring-opening polymerization of l-DOPA-N-carboxyanhydride (DOPA-NCA), l-arginine-NCA (Arg-NCA), l-cysteine-NCA (Cys-NCA), and ε-N-acryloyl lysine-NCA (Ac-Lys-NCA). These copolymers demonstrated good biodegradability, biocompatibility, and thermoresponsive properties. Adhesion tests using porcine skin and bone as adherends demonstrated lap-shear adhesion strengths up to 106 kPa and tensile adhesion strengths up to 675 kPa. The antibleeding activity and tissue adhesive ability were evaluated using a rat model. These polypeptide-Pluronic copolymer glues showed superior hemostatic properties and superior effects in wound healing and osteotomy gaps. Complete healing of skin incisions and remodeling of osteotomy gaps were observed in all rats after 14 and 60 days, respectively. These copolymers have potential uses as tissue adhesives, antibleeding, and tissue engineering materials.

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In this study, thermoresponsive and mussel-inspired polypeptides were synthesized using ring-opening polymerization of α-amino acid derivatives of N-carboxyanhydride (NCA). The tissue adhesive properties of these polypeptides were evaluated using in vitro adhesive strength tests on porcine skin and bone. The results indicated that the species of the functional polypeptide side groups and the adhesive temperature have a significant influence on the adhesion strength. The maximum of the lap-shear adhesion strength on porcine skin was 101.2 kPa, and the maximum of tensile adhesion strength on bone was 603 kPa. The in vivo antibleeding activity and tissue adhesive ability were also evaluated using a rat model. These polypeptides exhibited superior hemostatic properties and healing effects in the skin incision and osteotomy gap, and the skin incision healing and osteotomy gap remodeling were completed in all rats after 2–9 weeks. These polypeptides are expected to be good candidates for surgical tissue adhesives, tissue engineering materials, and antibleeding materials, etc.

The adhesive strength of poly(amino acid)s can be improved by clicking a cross-link, forming a disulfide bond and so on. In addition, the adhesion strength becomes better on grafting with different monomers at 37 °C.

Poly(glutamic acid-co-lactic acid-co-glycolic acid) (PGLG), an amphiphilic biodegradable copolymer, was synthesized by simply heating a mixture of L-glutamic acid (Glu), DL-lactic acid, and glycolic acid with the present of stannous chloride. The unique branched architecture comprising of glutarimide unit, polyester unit, and polyamide unit was confirmed by NMR spectrum. The PGLG was soluble in many organic solvents and aqueous solution of sodium hydroxide (pH 9.0). The thermal properties were evaluated using thermogravimetric analysis and differential scanning calorimetry. Molecular weights were determined by 1 H NMR end-group analysis and GPC, respectively, and the results indicated that the higher Glu content resulted in a decrease of the molecular weight.

Although the fascinating emission of natural carbohydrates containing a large number of glucose units has been found and has attracted much interest because of potential applications in biomedical areas, cyclodextrin similar to these carbohydrates has unfortunately not shown analogous luminescent behaviors at room temperature. The objective of this study is to realize the strong fluorescence of cyclodextrin containing no conventional chromophore. In this work, a new di­ethylene­tri­amino-styryl-bridged bis (β-cyclodextrin) dimer and its polymer are synthesized by convenient methods, and strong blue photoluminescence is observed even with the naked eye under an ultraviolet lamp. Studies on the molecular structure and the properties of aggregation-induced emission show that the strong fluorescence emissions are produced by the intermolecular hydrogen bonding of amide and hydroxyl groups in aggregation states. Thus, this study opens a new route for synthesizing fluorescent cyclodextrin containing unconventional chromophores for cell imaging, biosensing, and drug delivery.

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