Water-Swellable Cellulose Nanofiber Aerogel for Control of Hemorrhage from Penetrating Wounds

Ionic Potential Relaxation Effect in a Hydrogel Enabling Synapse-Like Information Processing

The next-generation brain-like intelligence based on neuromorphic architectures emphasizes learning the ionic language of the brain, aiming for efficient brain-like computation and seamless human-computer interaction. Ionic neuromorphic devices, with ions serving as information carriers, provide possibilities to achieve this goal. Soft and biocompatible ionic conductive hydrogels are an ideal substrate for constructing ionic neuromorphic devices, but it remains a challenge to modulate the ion transport behavior in hydrogels to mimic neuroelectric signals. Here, we describe an ionic potential relaxation effect in a hydrogel device prepared by sandwiching a layer of polycationic hydrogel (CH) between two layers of neutral hydrogel (NH), allowing this device to simulate various electrical signal patterns observed in biological synapses, including short- and long-term plasticity patterns. Theoretical and experimental results show that the selective permeation and hysteretic diffusion of ions caused by the anion selectivity of the CH layer are responsible for potential relaxation. Such an effect allows us with hydrogels to enable synapse-like information processing functions, including tactile perception, learning, memory, and neuromorphic computing. Additionally, the hydrogel device can operate stably even under 180° bending and 50% tensile strain, expanding the pathway for implementing advanced brain-like intelligent systems.

Superhydrophobic Cellulose Nanofiber Aerogels for Efficient Hemostasis with Minimal Blood Loss

Reducing unnecessary blood loss in hemostasis is a major challenge for traditional hemostatic materials due to uncontrolled blood absorption. Tuning the hydrophilic and hydrophobic properties of hemostatic materials provides a road to reduce blood loss. Here, we developed a superhydrophobic aerogel that enabled remarkably reduced blood loss. The aerogel was fabricated with polydopamine-coated and fluoroalkyl chain-modified bacterial cellulose via a directional freeze-drying method. Primarily, the hydrophobic feature prevented blood from uncontrolled absorption by the material and overflowing laterally. Additionally, the aerogel had a dense network of channels that allowed it to absorb water from blood due to the capillary effect, and fluoroalkyl chains trapped the blood cells entering the channels to form a compact barrier via hydrophobic interaction at the bottom of the aerogel, causing quick fibrin generation and blood coagulation. The animal experiments reveal that the aerogel reduced the hemostatic time by 68% and blood loss by 87 wt % compared with QuikClot combat gauze. The study demonstrates the superiority of superhydrophobic aerogels for hemostasis and provides new insights into the development of hemostatic materials.

The Biosynthesis of Bacterial Cellulose Composites Accompanied by Spray Feeding of Biomasses

Bacterial cellulose (BC) is a broadly utilized natural nanofiber produced by microbial fermentation, but its high-cost and low-yield production and limited function still hinder its application. Here, we used the spraying-assisted biosynthesis method to introduce biomass nanofibers along with the nutrient media to the fermenting BC. Biomass nanofibers could be cellulose, chitosan, and others. They entangled with BC nanofibers via intermolecular interactions, including hydrogen binding and electrostatic adsorption, to form uniform BC composites. The BC composites achieved an enhanced yield of ~140 wt% compared with pure BC and displayed similar excellent mechanical properties (Young's moduli = 0.9-1.4 MPa for wet films and =~6500 MPa for dried films). BC composites also had similar high crystallinity and thermal stability to pure BC. The functional groups of biomasses endowed BC composite additional functions such as antibacterial and dye-adsorption capabilities. Moreover, a high yield and functionalization could be realized simultaneously by feeding functional cellulose nanofibers. This method provides a facile way to produce BC composites with low cost, high yield, and multiple functions.

Bioadhesive and drug-loaded cellulose nanofiber/alginate film for healing oral mucosal wounds

Recurrent oral ulcers are common oral mucosal lesions that severely reduce patients' quality of life. Commercial mucoadhesive films are easily disrupted due to oral movement and complex wet environments, thus reducing drug utilization and even causing toxic side effects. Herein, we report a mucoadhesive film composed of Ca2+-crosslinked carboxymethylated cellulose nanofibers and alginate, in which two drugs of dexamethasone (DXM) and dyclonine hydrochloride (DYC) are loaded for the treatment of oral ulcers. The wet films have a high Young's modulus of 7.1 ± 2.6 MPa and a large strain of 53.6 ± 9.8 % and adhere to tissue strongly, which allows them to resist the deformation caused by frequent oral movement. The films also have nice durability against water and excellent biocompatibility. Moreover, the drug release was controlled at different rates. The fast release of DYC facilitates the quick relief of pain, while the slow release of DXM benefits the long-term treatment of wounds. Finally, the animal experiment demonstrates the films displayed excellent therapeutic efficacy in healing oral ulcers.

A Cost-Effective and Chemical-Recycling Approach for Facile Preparation of Regenerated Cellulose Materials

Cellulose is difficult to melt or dissolve. The dissolution and regeneration process paves the way to convert cellulose into diverse forms but still suffers from high costs and environmental pollution. Here, we developed a method that uses aqueous alkali to efficiently dissolve cellulose at a temperature above 0 °C in minutes for fabricating regenerated cellulose. Cellulose was modified with minimal carboxymethyl groups to weaken the intermolecular interaction and improve its dissolution. The modified cellulose can be commercially obtained from carboxymethyl cellulose manufacturing with low cost and high quality. The use of only aqueous alkali reduces pollution and facilitates chemical recycling, and the moderate dissolving temperature reduces energy consumption. The regenerated cellulose materials display excellent mechanical properties and can be recycled or biodegraded after use. The method allows the use of diverse raw materials and modifications to broaden its applicability. The study develops a low-cost and eco-friendly method to fabricate regenerated cellulose.

Biopolymer-Based Biomimetic Aerogel for Biomedical Applications

Aerogels are lightweight and highly porous materials that have been found to have great potential in biomedical research because of some of their unique properties, such as their high surface area, tunable porosity, and biocompatibility. Researchers have been exploring ways to use aerogels to create biomimetic scaffolds inspired by natural extracellular matrices (ECMs) for various biomedical applications. Aerogel scaffolds can serve as three-dimensional (3D) templates for cell growth and tissue regeneration, promoting wound healing and tissue repair. Additionally, aerogel-based scaffolds have great potential in controlled drug delivery systems, where their high surface area and porosity enable the efficient loading and release of therapeutic agents. In this review, we discuss biopolymer-based biomimetic aerogel scaffolds for tissue engineering, drug delivery, and biosensors. Finally, we also discuss the potential directions in the development of aerogel-based biomimetic scaffolds.

Advancements in Aerogel Technology for Antimicrobial Therapy: A Review

This paper explores the latest advancements in aerogel technology for antimicrobial therapy, revealing their interesting capacity that could improve the current medical approaches for antimicrobial treatments. Aerogels are attractive matrices because they can have an antimicrobial effect on their own, but they can also provide efficient delivery of antimicrobial compounds. Their interesting properties, such as high porosity, ultra-lightweight, and large surface area, make them suitable for such applications. The fundamentals of aerogels and mechanisms of action are discussed. The paper also highlights aerogels' importance in addressing current pressing challenges related to infection management, like the limited drug delivery alternatives and growing resistance to antimicrobial agents. It also covers the potential applications of aerogels in antimicrobial therapy and their possible limitations.

Recent Advances in Topical Hemostatic Materials

Untimely or improper treatment of traumatic bleeding may cause secondary injuries and even death. The traditional hemostatic modes can no longer meet requirements of coping with complicated bleeding emergencies. With scientific and technological advancements, a variety of topical hemostatic materials have been investigated involving inorganic, biological, polysaccharide, and carbon-based hemostatic materials. These materials have their respective merits and defects. In this work, the application and mechanism of the major hemostatic materials, especially some hemostatic nanomaterials with excellent adhesion, good biocompatibility, low toxicity, and high adsorption capacity, are summarized. In the future, it is the prospect to develop multifunctional hemostatic materials with hemostasis and antibacterial and anti-inflammatory properties for promoting wound healing.