Post-synthesis modification of hydrogels. Total and partial rupture of crosslinks: Formation of aldehyde groups and re-crosslinking of cleaved hydrogels

Novel Vectors and Administrations for mRNA Delivery

mRNA therapy has shown great potential in infectious disease vaccines, cancer immunotherapy, protein replacement therapy, gene editing, and other fields due to its central role in all life processes. However, mRNA is challenging to pass through the cell membrane due to its significant negative charges and degradation from RNase, so the key to mRNA therapy is efficient packaging and delivery of it with appropriate vectors. Presently researchers have developed various vectors such as viruses and liposomes, but these conventional vectors are now difficult to meet the growing requirement like safety, efficiency, and targeting, so many novel delivery vectors with unique advantages have emerged recently. This review mainly introduces two categories of novel vectors: biomacromolecules and inorganic nanoparticles, as well as two novel methods of control and administration based on these novel vectors: controlled-release administration and non-invasive administration. These novel delivery strategies have the advantages of high safety, biocompatibility, versatility, intelligence, and targeting. This paper analyzes the challenges faced by the field of mRNA delivery in depth, and discusses how to use the characteristics of novel vectors and administrations to solve these problems.

Covalent Adaptable Polymethacrylate Networks by Hydrazide Crosslinking Via Isosorbide Levulinate Side Groups

Reversible crosslinking offers an attractive strategy to modify and improve the properties of polymer materials while concurrently enabling a pathway for chemical recycling. This can, for example, be achieved by incorporating a ketone functionality into the polymer structure to enable post-polymerization crosslinking with dihydrazides. The resulting covalent adaptable network contains acylhydrazone bonds cleavable under acidic conditions, thereby providing reversibility. In the present work, we regioselectively prepare a novel isosorbide monomethacrylate with a pendant levulinoyl group via a two-step biocatalytic synthesis. Subsequently, a series of copolymers with different contents of the levulinic isosorbide monomer and methyl methacrylate are prepared by radical polymerization. Using dihydrazides, these linear copolymers are then crosslinked via reaction with the ketone groups in the levulinic side chains. Compared to the linear prepolymers, the crosslinked networks exhibit enhanced glass transition temperatures and thermal stability, up to 170 and 286 °C, respectively. Moreover, the dynamic covalent acylhydrazone bonds are efficiently and selectively cleaved under acidic conditions to retrieve the linear polymethacrylates. We next show that recovered polymers can again be crosslinked with adipic dihydrazide, thus demonstrating the circularity of the materials. Consequently, we envision that these novel levulinic isosorbide-based dynamic polymethacrylate networks have great potential in the field of recyclable and reusable biobased thermoset polymers.

Aldehyde-mediated adaptive membranes with self-healing and antimicrobial properties for endometrial repair

Traditional treatment methods for irreversible endometrial damage face a number of challenges in clinical practice, the most important of which are bacterial infection and the inability to restore endometrial function. By modifying glucan, oxidized dextran (OD) with multifunctional aldehyde groups was obtained in this study. Based on the dynamic Schiff base reaction between gelatin (GA) and OD, a GA-OD adaptive membrane with good biocompatibility, self-healing, biodegradability, and antimicrobial properties was created. In vitro studies revealed that GA and OD cross-linking overcame GA's low gel temperature, accelerated gelling, and improved mechanical properties, hydrophilicity, and degradability. The dynamic bond formed by the reaction between GA and OD caused the GA-OD film to self-heal. Meanwhile, the GA-OD membrane had antibacterial properties. To assess the repair effect of GA-OD film, an in vivo rat endometrial injury model filled with GA-OD adaptive membrane was created. According to the results of the study, the GA-OD membrane was biocompatible, and the uterine tissue did not have edema and inflammation. Further study on the postoperative endometrial regeneration effect of GA-OD material showed that it had an excellent ability for epithelial reconstruction and cell proliferation. As a result, the use of GA-OD composite film in endometrial repair has promising therapeutic implications.

Novel Trends in Hydrogel Development for Biomedical Applications: A Review

Nowadays, there are still numerous challenges for well-known biomedical applications, such as tissue engineering (TE), wound healing and controlled drug delivery, which must be faced and solved. Hydrogels have been proposed as excellent candidates for these applications, as they have promising properties for the mentioned applications, including biocompatibility, biodegradability, great absorption capacity and tunable mechanical properties. However, depending on the material or the manufacturing method, the resulting hydrogel may not be up to the specific task for which it is designed, thus there are different approaches proposed to enhance hydrogel performance for the requirements of the application in question. The main purpose of this review article was to summarize the most recent trends of hydrogel technology, going through the most used polymeric materials and the most popular hydrogel synthesis methods in recent years, including different strategies of enhancing hydrogels’ properties, such as cross-linking and the manufacture of composite hydrogels. In addition, the secondary objective of this review was to briefly discuss other novel applications of hydrogels that have been proposed in the past few years which have drawn a lot of attention.

Smart material based on boron crosslinked polymers with potential applications in cancer radiation therapy

Organoboron compounds have been playing an increasingly important role in analytical chemistry, material science, health applications, and particularly as functional polymers like boron carriers for cancer therapy. There are two main applications of boron isotopes in radiation cancer therapy, Boron Neutron Capture Therapy and Proton Boron Fusion Therapy. In this study, a novel and original material consisting of a three-dimensional polymer network crosslinked with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{10}$$\end{document}10B enriched boric acid molecules is proposed and synthesized. The effects of the exposition to thermal neutrons were studied analyzing changes in the mechanical properties of the proposed material. Dedicated Monte Carlo simulations, based on MCNP and FLUKA main codes, were performed to characterize interactions of the proposed material with neutrons, photons, and charged particles typically present in mixed fields in nuclear reactor irradiations. Experimental results and Monte Carlo simulations were in agreement, thus justifying further studies of this promising material.

Versatile Types of Polysaccharide-Based Drug Delivery Systems: From Strategic Design to Cancer Therapy

Chemotherapy is still the most direct and effective means of cancer therapy nowadays. The proposal of drug delivery systems (DDSs) has effectively improved many shortcomings of traditional chemotherapy drugs. The technical support of DDSs lies in their excellent material properties. Polysaccharides include a series of natural polymers, such as chitosan, hyaluronic acid, and alginic acid. These polysaccharides have good biocompatibility and degradability, and they are easily chemical modified. Therefore, polysaccharides are ideal candidate materials to construct DDSs, and their clinical application prospects have been favored by researchers. On the basis of versatile types of polysaccharides, this review elaborates their applications from strategic design to cancer therapy. The construction and modification methods of polysaccharide-based DDSs are specifically explained, and the latest research progress of polysaccharide-based DDSs in cancer therapy are also summarized. The purpose of this review is to provide a reference for the design and preparation of polysaccharide-based DDSs with excellent performance.