Search

As a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products. [ABSTRACT FROM AUTHOR]

A series of porous organic frameworks (POFs), namely POF-1, POF-2, and POF-3, has been successfully designed and constructed via a Friedel–Crafts reaction. By virtue of the outstretched π-conjugation structure, high surface area, and large pore cavity, these samples have the potential ability to load aptamer strands via strong π–π stacking interactions to fabricate electrochemical aptasensors. The label-free electrochemical aptasensor based on POF-3 can detect kanamycin ultra-sensitively with high selectively with a limit of detection of 0.0145 fg mL−1 over a wide concentration range from 1.0 × 10−5 to 10.0 pg mL−1via electrochemical impedance spectroscopy; meanwhile, the fabricated aptasensor reveals excellent selectivity in the presence of interferents at 1.0 × 103 pg mL−1, which is 1.0 × 108 times higher than the concentration of kanamycin (1.0 × 10−5 pg mL−1). Furthermore, the fabricated aptasensor can detect ultra-trace levels of kanamycin in real milk and human serum samples. As a result, this work exhibits a highly efficient approach for accurately detecting kanamycin. [ABSTRACT FROM AUTHOR]

Four-dimensional (4D) printing is a promising technology that provides solutions for compelling needs in various fields. Most of the reported 4D printed systems are based on the temporal shape transformation of printed subjects. Induction of temporal heterogenicity in functions in addition to shape may extend the scope of 4D printing. Herein, we report a 4D printing approach using plant protein (zein) gel inspired by the amyloid fibrils formation mechanism. The printing of zein gel in a specialized layered-Carbopol supporting bath with different water concentrations in an ethanol-water mixture modulates hydrophobic and hydrogen bonding that causes temporal changes in functions. The part of the construct printed in a supporting bath with higher water content exhibits higher drug loading, faster drug release and degradation than those printed in the supporting bath with lower water content. Tri-segment conduit and butterfly-shaped construct with two asymmetrical wings are printed using this system to evaluate biomedical function as nerve conduit and drug delivery system. 4D printed conduits are also effective as a drug-eluting urethral stent in the porcine model. Overall, this study extends the concept of 4D printing beyond shape transformation and presents an approach of fabricating specialized baths for 4D printing that can also be extended to other materials to obtain 4D printed medical devices with translational potential., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)