The Potential of Sugarcane Waste-Derived Cellulose Fibres as Haemostatic Agents.

Haemorrhage control during surgery and following traumatic injury remains a critical, life-saving challenge. Cellulose products are already employed in commercially available haemostatic dressings. This work explores sourcing cellulose from sugarcane trash pulp to produce micro- and nanosized fibres with hydroxyl, carboxylic acid, and trimethylamine functional groups, resulting in either positive or negative surface charges. This paper assesses the influence of these fibres on multiple blood clotting parameters in both dispersed solutions and dry gauze applications. In vitro blood clotting studies demonstrated the significant haemostatic potential of cellulose fibres derived from sugarcane waste to initiate clotting. Plasma absorbance assays showed that the 0.25 mg/mL cellulose microfibre dispersion had the highest clotting performance. It was observed that no single property of surface charge, functionality, or fibre morphology exclusively controlled the clotting initiation measured. Instead, a combination of these factors affected clot formation, with negatively charged cellulose microfibres comprising hydroxyl surface groups providing the most promising result, accelerating the coagulation cascade mechanism by 67% compared to the endogenous activity. This difference in clot initiation shows the potential for the non-wood agricultural waste source of cellulose in haemostatic wound healing applications, contributing to the broader understanding of cellulose-based materials' versatility and their applications in biomedicine.

Snake venom-defined fibrin architecture dictates fibroblast survival and differentiation.

Fibrin is the provisional matrix formed after injury, setting the trajectory for the subsequent stages of wound healing. It is commonly used as a wound sealant and a natural hydrogel for three-dimensional (3D) biophysical studies. However, the traditional thrombin-driven fibrin systems are poorly controlled. Therefore, the precise roles of fibrin's biophysical properties on fibroblast functions, which underlie healing outcomes, are unknown. Here, we establish a snake venom-controlled fibrin system with precisely and independently tuned architectural and mechanical properties. Employing this defined system, we show that fibrin architecture influences fibroblast survival, spreading phenotype, and differentiation. A fine fibrin architecture is a key prerequisite for fibroblast differentiation, while a coarse architecture induces cell loss and disengages fibroblast's sensitivity towards TGF-ß1. Our results demonstrate that snake venom-controlled fibrin can precisely control fibroblast differentiation. Applying these biophysical principles to fibrin sealants has translational significance in regenerative medicine and tissue engineering.

Snake Venom Hydrogels as a Rapid Hemostatic Agent for Uncontrolled Bleeding.

Uncontrolled bleeding from traumatic injury remains the leading cause of preventable death with loss of balance between blood clotting (coagulation) and blood clot breakdown (fibrinolysis). A major limitation of existing hemostatic agents is that they require a functioning clotting system to control the bleeding and are largely based on gauze delivery scaffolds. Herein, a novel rapid wound sealant, composed of two recombinant snake venom proteins, the procoagulant ecarin, to rapidly initiate blood clotting and the antifibrinolytic textilinin, to prevent blood clot breakdown within a synthetic thermoresponsive hydrogel scaffold is developed. In vitro, it is demonstrated that clotting is rapidly initiated with only nanomolar concentrations of venom protein and clot breakdown is effectively inhibited by textilinin. A stable clot is formed within 60 s compared to normal clot formation in 8 min. In vivo studies reveal that the snake venom hydrogel rapidly controls warfarin-induced bleeding, reducing the bleed volume from 48% to 12% and has demonstrated immune compatibility. A new class of hemostatic agents that achieve formation of rapid and stable blood clots even in the presence of blood thinners is demonstrated here.

Nano polydopamine crosslinked thiol-functionalized hyaluronic acid hydrogel for angiogenic drug delivery.

Crosslinking of polymeric network using nanoparticles by physical or chemical method to obtain hydrogel is an emerging approach. Herein, we synthesized Polydopamine (PDA) nanoparticles via oxidative self-polymerization of dopamine in water-ethanol mixture. Thiol-functionalized hyaluronic acid was developed using cysteamine and hyaluronic acid (HA-Cys) via 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide - N-hydroxysuccinimide (EDC-NHS) crosslinking chemistry. Developed HA-Cys conjugate was cross-linked using PDA nanoparticles via Michael-type addition reaction. Synthesized nanoparticles were monodisperse with size of 124 ± 8 nm and had spherical morphology. FTIR characterization confirmed successful synthesis of HA-Cys conjugate and subsequent crosslinking with PDA nanoparticles. Rheological characterization revealed that hydrogels were injectable in nature with good mechanical stability. Dimethyloxalylglycine (DMOG) loaded PDA nanoparticle showed sustained drug release for period of 7 days from composite hydrogel. Hydrogel microenvironment facilitated enhanced endothelial cell migration, proliferation and attachment. Furthermore, in response to release of DMOG from developed hydrogel, cells showed enhanced capillary tube formation in vitro. Overall, these results demonstrate that PDA cross-linked thiol-functionalized hydrogel was developed in a facile manner under physiological conditions. These developed hydrogels could be potentially used in tissue engineering and drug delivery.

Antistaphylococcal and Neutrophil Chemotactic Injectable κ-Carrageenan Hydrogel for Infectious Wound Healing.

Staphylococcus aureus wound infection is a major concern due to the resistance of S. aureus to topical antibiotics and capacity to inhibit neutrophil migration at the infection site. To overcome these problems, we have developed 0.01% (v/v) octenidine dihydrochloride (Oct) and 0.5% (w/w) chitosan-treated serum (CTS) containing 1.5% (w/v) κ-carrageenan hydrogel (κC). Oct is an antiseptic agent, against which no resistance is reported so far, and CTS has neutrophilic attractant properties. The prepared Oct-CTS-κC hydrogel is injectable and biocompatible. Using in vitro experiments, we demonstrated CTS can induce the migration of polymorphonuclear neutrophils (PMNs) and fibroblasts that can facilitate tissue regeneration at a wound site. In vitro release studies revealed a sustained release of Oct and serum proteins from the Oct-CTS-κC hydrogel. Antibacterial properties of developed hydrogels were tested against S. aureus and its clinical isolates. Further, the in vivo antibacterial efficacy of the prepared hydrogel was evaluated in an S. aureus-infected Sprague-Dawley (SD) rat wound. Both in vitro and in vivo studies showed that the Oct-CTS-κC hydrogel inhibited S. aureus growth. Thus, the developed Oct-CTS-κC hydrogel can be potentially exploited for S. aureus-infected wound healing.

Injectable angiogenic and osteogenic carrageenan nanocomposite hydrogel for bone tissue engineering.

Functional biomaterials that couple angiogenesis and osteogenesis processes are vital for bone tissue engineering and bone remodeling. Herein we developed an injectable carrageenan nanocomposite hydrogel incorporated with whitlockite nanoparticles and an angiogenic drug, dimethyloxallylglycine. Synthesized whitlockite nanoparticles and nanocomposite hydrogels were characterized using SEM, TEM, EDS and FTIR. Developed hydrogels were injectable, mechanically stable, cytocompatible and has better protein adsorption. Incorporation of dimethyloxallylglycine resulted in initial burst release followed by sustained release for 7 days. Human umbilical vein endothelial cells exposed to dimethyloxallylglycine incorporated nanocomposite hydrogel showed enhanced cell migration and capillary tube-like structure formation. Osteogenic differentiation in rat adipose derived mesenchymal stem cells after 7 and 14 days revealed increased levels of alkaline phosphatase activity in vitro. Furthermore, cells exposed to nanocomposite hydrogel revealed enhanced protein expressions of RUNX2, COL and OPN. Overall, these results suggest that incorporation of whitlockite and dimethyloxallylglycine in carrageenan hydrogel promoted osteogenesis and angiogenesis in vitro.

Carrageenan based hydrogels for drug delivery, tissue engineering and wound healing.

Carrageenan is a class of naturally occurring sulphated polysaccharides, which is currently a promising candidate in tissue engineering and regenerative medicine as it resemblances native glycosaminoglycans. From pharmaceutical drug formulations to tissue engineered scaffolds, carrageenan has broad range of applications. Here we provide an overview of developing various forms of carrageenan based hydrogels. We focus on how these fabrication processes has an effect on physiochemical properties of the hydrogel. We outline the application of these hydrogels not only pertaining to sustained drug release but also their application in bone and cartilage tissue engineering as well as in wound healing and antimicrobial formulations. Administration of these hydrogels through various routes for drug delivery applications has been critically reviewed. Finally, we conclude by summarizing the current and future outlook that promotes the seaweed-derived polysaccharide as versatile, promising biomaterial for a variety of bioengineering applications.

Sequential Thiol-Ene and Tetrazine Click Reactions for the Polymerization and Functionalization of Hydrogel Microparticles.

Click chemistry is a versatile tool for the synthesis and functionalization of polymeric biomaterials. Here, we describe a versatile new strategy for producing bioactive, protein-functionalized poly(ethylene glycol) (PEG) hydrogel microparticles that is based on sequential thiol-ene and tetrazine click reactions. Briefly, tetra-functional PEG-norbornene macromer and dithiothreitol (SH) cross-linker were combined at a 0.75:1 [SH]:[norbornene] ratio, emulsified in a continuous Dextran phase, and then photopolymerized to form PEG hydrogel microparticles that varied from 8 to 30 µm in diameter, depending on the PEG concentration used. Subsequently, tetrazine-functionalized protein was conjugated to unreacted norbornene groups in the PEG microparticles. Tetrazine-mediated protein tethering to the microparticles was first demonstrated using fluorescein-labeled ovalbumin as a model protein. Subsequently, bioactive protein tethering was demonstrated using alkaline phosphatase (ALP) and glucose oxidase (GOx). Enzyme activity assays demonstrated that both ALP and GOx maintained their bioactivity and imparted tunable bioactivity to the microparticles that depended on the amount of enzyme added. ALP-functionalized microparticles were also observed to initiate calcium phosphate mineralization in vitro when incubated with calcium glycerophosphate. Collectively, these results show that protein-functionalized hydrogel microparticles with tunable bioactive properties can be easily synthesized using sequential click chemistry reactions. This approach has potential for future applications in tissue engineering, drug delivery, and biosensing.