Injectable bottlebrush hydrogels with tissue-mimetic mechanical properties

Abstract

Injectable hydrogels are desired in many biomedical applications due to their minimally invasive deployment to the body and their ability to introduce drugs. However, current injectables suffer from mechanical mismatch with tissue, fragility, water expulsion, and high viscosity. To address these issues, we design brush-like macromolecules that concurrently provide softness, firmness, strength, fluidity, and swellability. The synthesized linear-bottlebrush-linear (LBL) copolymers facilitate improved injectability as the compact conformation of bottlebrush blocks results in low solution viscosity, while the thermoresponsive linear blocks permit prompt gelation at 37°C. The resulting hydrogels mimic the deformation response of supersoft tissues such as adipose and brain while withstanding deformations of 700% and precluding water expulsion upon gelation. Given their low cytotoxicity and mild inflammation in vivo, the developed materials will have vital implications for reconstructive surgery, tissue engineering, and drug delivery applications.

A Poly (Caprolactone)-Cellulose Nanocomposite Hydrogel for Transdermal Delivery of Hydrocortisone in Treating Psoriasis Vulgaris

“…Hydrogels are popular in biological applications because of their low invasiveness and capacity to deliver medicines [17]. Due to their low cytotoxicity and mild inflammation in vivo, hydrogels have critical implications for reconstructive surgery, tissue engineering, and drug-delivery applications [17]. Ziai et al (2022), mentioned that bimolecular sensing is one of the most exciting areas in the field of smart biopolymers.…”

Entropy‐Mediated Polymer–Cluster Interactions Enable Dramatic Thermal Stiffening Hydrogels for Mechanoadaptive Smart Fabrics

“…These control experiments strongly reveal the important role of polymer-cluster interactions in the dramatic thermal stiffening behavior of mineral hydrogels, which also make our design largely differ from the previously reported thermal stiffening hydrogels with a relatively homogeneous network. [12,[15][16][17][18]20] To highlight the unprecedented thermal stiffening effect of ACC-PAA mineral hydrogel, we compared the storage modulus changing ranges and stiffening enhancements among a few previously reported thermal stiffening materials. Note that, Young's modulus determined from tensile or compressive tests was not chosen as the evaluating parameter in this work due to large calculation errors, while storage modulus determined from rheological or dynamic mechanical analysis (DMA) tests is much more reliable for comparison.…”

Two-Dimensional and Three-Dimensional Ultrathin Multilayer Hydrogels through Layer-by-Layer Assembly

“…Cross-linked polymeric networks that can absorb large amounts of water (100- to 1000-fold) and host a variety of functional molecules are known as hydrogels and have become critical soft materials for sustainable technologies and biomedicine. − Hydrogels’ ability to mimic human tissue rigidities and model the pathological tissue environment is highly desirable for advanced biomedical applications. − To mimic tissues’ complex hierarchical structures to program varied mechanical and biochemical behaviors, bulk hydrogels made of hydrogel stacks have been developed using polymer layered technologies, including photopolymerization, electrospinning, and sequential physical bonding. − The pH- and temperature-responsive macromolecules have often been used to develop responsive hydrogels that can change their dimensions and physical properties in a controlled way under external triggers and have been shown to be critical for the controlled delivery of therapeutics and biosensing. − …”