Gelation Mechanism Research Articles

Recent opportunities and application of gellan gum based drug delivery system for intranasal route.

In the recent years, in-situ hydrogel based on gellan gum has been investigated for delivery of various drug molecules particularly to treat neurological disorders via intranasal route. The major objective of the present manuscript is to review the recent research studies exploring gellan gum as ionic triggered in-situ gel for intranasal administration to enhance absorption of drugs and to increase their therapeutic efficacy. This review include literature from 1982 to 2023 and were collected from various scientific electronic databases like Scopus, PubMed and Google Scholar to review source, chemistry, ionotropic gelation mechanism, and recent research studies for gellan gum based in-situ hydrogel for intransasl administration.Keywords such as gellan gum, in-situ hydrogel, intranasal administration and brain targeting were used to search literature. The present review included the research studies which explored gellan gum based in-situ gel for intranasal drug delivery. The findings have shown enhanced biavailability of various drugs upon intranasal administration using gellan-gum based in-situ hydrogel.Moreover, the review indicated that intranasal administration of in-situ hydrogel facilitate to overcome blood brain barrier effectively. Hence, significantly higher drug concentration was found to be achieved in brain tissues upon intranasal administration than that of other routes like oral and intravenous. The present work conducted a comprehensive review for gellan gum based in-situ hydrogel particularly for intransal administration to overcome BBB. The study concluded that gellan gum based in-situ hydrogel could be potential promising delivery system for intranasal administration to improve bioavailability and efficacy of drugs specifically to treat neurological disorders.

Sodium caseinate/gellan gum emulsion gels for zeaxanthin dipalmitate delivery: Preparation, characterization, and gelation mechanism

The emulsion gel composed of proteins and polysaccharides exhibits significant potential as a targeted delivery system for bioactives in the gastrointestinal tract. In this study, a composite emulsion was prepared by using sodium caseinate (NaCas) and gellan gum (GG), which was subsequently crosslinked with transglutaminase (TG), glucono-δ-lactone (GDL), and calcium ions (Ca2+) to form emulsion gels. The physicochemical properties of the NaCas/GG emulsion gels were characterized to verify the effects of zeaxanthin dipalmitate encapsulation and protection, and a possible mechanism was discussed. The appearance and microscopy analyses revealed that the Ca2+-induced NaCas/GG emulsion gel exhibited superior shape retention and a denser network structure compared to GDL or TG crosslinking methods. The rheological analysis demonstrated that the Ca2+-crosslinked emulsion gels had higher modulus and hardness than their TG- or GDL- crosslinked counterparts. Infrared spectroscopy, molecular docking, and gelling force analysis revealed that the gelation mechanism of these emulsion gels primarily involved carbonyl-amide group crosslinking reactions, hydrogen bonding, and hydrophobic interactions. Furthermore, the Ca2+-crosslinked emulsion gel encapsulating zeaxanthin dipalmitate exhibited excellent thermal stability, resistance to gastrointestinal conditions, and stability. Overall, the above findings highlight that using Ca2+ crosslinking in NaCas/GG composite emulsion yields edible composite materials with enhanced functional performance, thereby expanding the possibilities for food gel design strategies.

Effect of gel composition interaction on rheological, physicochemical and textural properties of methyl cellulose oleogels and lard replacement in ham sausage

Cellulose-derived edible vegetable oleogels can replace saturated/trans fats. The gelation mechanism relies on non-covalent interactions between gel components, influenced by their structure, concentration, and nature of the gelling factors. On the premise of preparing methyl cellulose (MC) with different viscosity, the effects of different gelling agents, MC, gelatin and oil concentration on the structure, physicochemical properties, oil binding capacity (OBC) and texture of emulsion and oleogels were studied. The oleogels were used as a lard substitute to study the effect on the texture, structure and sensory properties of the prepared ham sausage. We found that MC3 with gelatin had superior emulsification properties, inhibiting particle size and aggregation. Raising MC3 and gelatin concentrations to 1.5 wt% and 0.5 wt% led to oleogels with high OBC (>95 %), stability, and viscosity. The oleogels exhibited a dense structure and high mechanical strength with significantly enhanced structural hardness (199.55 g and 226.44 g). Higher oil concentration stabilized the emulsion but reduced oleogels stability after freeze-drying due to saturated oil absorption. The ratio of oleogels replacing lard was closely related to the texture of ham sausage. The texture properties of the ham sausage with 50 % lard replacement were closest to those of the control group.

Transglutaminase–mucin binding dynamics in gastrointestinal mucus: Interfacial behaviour, thermodynamics and gelation mechanism

Transglutaminase, an enzyme present in epithelial cells and as a residual component in processed foods, is hypothesised to interact with gastrointestinal mucus, impacting its structure and function. To test the physical validity of this phenomenon, this study investigates the binding kinetics and thermodynamics between porcine gastric mucin (PGM) and microbial transglumatinse (TGM) in a model gastrointestinal mucus, followed by the rheological analysis of the resulting systems. At pH 7, TGM exhibited pronounced binding with the PGM interface, characterised by a high surface density (55.34 ± 1.86 µg/m−2) and a low dissociation constant (KD ∼ 4.03 ± 0.10 μM) as determined by surface plasma resonance (SPR). Conversely, at pH 3, TGM showed weak adhesion onto PGM, resulting in a less stable binding, reflected by a lower surface density (10.94 ± 0.67 µg/m−2) and a higher dissociation constant (KD ∼ 6.24 ± 0.22 μM). Regardless of the nature of interaction, the Hill coefficients (nH ≥ 1) indicated that the binding sites were markedly denser at pH 7 (1383.38 ± 46.47 pmol/m−2), than at pH 3 (273.68 ± 16.84 pmol/m−2). Fluorimetry analysis suggested temperature-dependent dynamic binding between PGM and TGM. The resulting Benesi – Hildebrand plots illustrated a linear correlation between PGM and increasing TGM concentration, suggesting a single-step interaction mechanism. The calculated thermodynamic parameters indicated spontaneous interaction between PGM and TGM (ΔG < 0) via endothermic (entropic) interactions (ΔH > 0). Notably, hydrophobic forces played a significant role in the network stabilisation of PGM−TGM complex (ΔS > 0). Rheometry analysis elucidates that the interaction maxima within TGM−PGM systems substantially elevate both shear viscosity (η), and the melting point (Tm), shifting from 6.75 ± 0.28 to 70.94 ± 2.21 (×10−3) Pa s (at 1 s−1), and 36.80 ± 0.80 to 48.20 ± 0.11 °C, respectively. Furthermore, the coexistence of these two macromolecular species results in a 3- to 4-fold dramatic increase in the viscoelastic moduli of the binary complex. These findings build a strong physicochemical basis for the interaction between TGM and PGM, with profound effects on the rhological behaviour of the latter; it also highlights the need to examine the biochemical/enzymatic aspects of said interactions, and their potential effects on mucosa and human physiology.

Internally-crosslinked alginate dialdehyde/alginate/gelatin-based hydrogels as bioprinting inks for prospective cardiac tissue engineering applications

Cardiovascular diseases represent a worldwide social and economic challenge, due to heart tissue limited regenerative capabilities. 3D bioprinted cell-laden constructs are a promising approach to develop patches for cardiac regeneration or in vitro models for new drug preclinical discovery and validation. However, the development of bioinks with optimal mechanical, rheological, and biological properties is still a challenge. Although alginate (Alg)-based bioinks have been extensively explored, such hydrogels lack cell adhesion properties and degradability. Additionally, 3D Alg structures are usually obtained by micro-extrusion bioprinting exploiting conventional external cross-linking methods, which introduce inhomogeneities and unpredictability in construct formation. This work exploits Alg internal ionic gelation mechanism to obtain homogeneous self-standing multilayered 3D printed constructs without employing support baths or post-printing crosslinking treatments, combining an insoluble calcium salt (calcium carbonate, CaCO3) with an acidifying agent (D-(+)-Glucono-1,5-lactone, GDL) to promote controlled release of calcium ions. Alg was blended with oxidized alginate (ADA) and gelatin (Gel) to achieve degradable and cell adhesive hydrogels for cardiac tissue engineering. Firstly, ADA/Alg bioink composition was tailored by varying polymer weight ratio (keeping ADA as the main component) and calcium ions concentration to achieve cardiac tissue-like viscoelastic properties. Then, the amount of Gel in ADA/Alg hydrogels was optimized to support adult human cardiac fibroblasts (AHCFs) adhesion, producing shear thinning inks with tunable viscoelastic properties (G&amp;rsquo; 650-1300 Pa) and degradation profile (40-80% weight loss after 21 days in phosphate buffered saline, PBS) by varying Gel concentration. ADA/Alg/Gel hydrogels showed a shear thinning behavior suitable for 3D bioprinting and dependent on ink stabilization time, due to the gradual pH-triggered release of calcium ions over time. AHCFs-laden ADA/Alg/Gel bioinks could be successfully printed producing scaffolds with high shape fidelity and good cell viability post-printing. Finally, 3D AHCF-laden and H9C2-laden ADA/Alg/Gel bioinks with the highest gelatin content (25% w/w) allowed cell adhesion after 24 hours of incubation, showing potential application for cardiac tissue modelling. This research presented a comprehensive framework for advancing the design of bioink formulations enabling the printing of cell-adhesive and self-supporting constructs.

Impact of diverse mineral hardness in electrodialysis water on the ionotropic gelation mechanism of low methoxyl pectin

In this study, the effect of desalinated lava seawater via electrodialysis (ED water) on the formation and properties of low methoxyl pectin (LMP) gels was investigated. Additionally, the syneresis, microstructure, gelation mechanism, and thermostability of the gel samples were analyzed. When the ED water content exceeded 25 %, pectin gels with viscosities and textures that differed from those of the sol were formed. The highest gel hardness (9.38 N) was observed when 50 % ED water was mixed with LMP. However, when 75 % ED water was added, the pore size of the LMP gel became the largest, and excess water was released from the gel, resulting in a weak gel strength (4.98 N). The formation and properties of the gel structure were found to be mainly due to the ionic bonds between the minerals in the ED water and the free carboxyl groups of pectin, and it was confirmed that the hydrogen bonds within the pectin chains also had an effect. These results suggest that the interaction between the ED water and LMP can be widely used in various industrial fields, including low-sugar gels or viscosity-enhancing agents with diverse rheological properties.

Legume protein gelation: The mechanism behind the formation of homogeneous and fractal gels

Protein gelation can provide texture in plant-based foods and can be influenced by many factors, including protein extraction method and salt addition. However, the protein gelation mechanism is still not well understood for plant proteins, especially for isolates obtained using commercial protein extraction processes. Therefore, the structural changes that legume sources such as yellow pea, faba bean, and soybeans undergo during the gelation process to understand the differences in their gelation mechanisms was investigated herein by using small-angle neutron scattering. Among these protein sources, the commercial extraction method was found to play a major part in the gelation pathway. Intensive protein extraction methods involving isoelectric precipitation led to lower protein solubility (∼1–38% w/w), larger insoluble protein particle sizes (60–100 μm), and a gelation pathway that is dependent on the changes of the insoluble protein particles. In contrast, extraction using ultrafiltration instead of precipitation resulted in higher protein solubility (∼18–88% w/w) and smaller insoluble protein particle sizes (40–70 μm), and the structural changes observed during gelation involved the structural changes of both soluble proteins and insoluble proteins. SEM imaging also showed different gel networks, with fractal networks formed by insoluble proteins (for sources with low solubility) or more homogenous networks formed by the interactions between the soluble proteins (for sources with high solubility). Despite the differences observed in the gelation network and the protein solubility, the gelation strength exhibited by protein sources at low protein solubility were similar to the ones by protein sources at high protein solubility, demonstrating the potential of fractal gel networks in providing texture.

Mechanisms of gelation induced by laser irradiation for CaO powder dispersed in ethanol – Formation of calcium acetate and its role in gelation

Our recent study of gelation induced by laser ablation of CaO powders dispersed in ethanol proposed that CaO particle size composition would be an important factor affecting gelation because gelation is brought about by mixing a colloid composed of laser-fragmented particles and a raw CaO colloid. The present work was conducted to clarify this point. Results showed that, differing from our assumption, laser-fragmented particles are not necessary for gelation because gelation occurred even when laser-fragmented particles were removed from a laser-irradiated colloid before mixing it with a raw CaO colloid. Moreover, findings revealed that acetic acid generated by laser-induced oxidation of ethanol causes gelation, as confirmed by the fact that gelation also occurred when a proper amount of acetic acid was added to a raw CaO colloid. Results also revealed that nanofibers composed of calcium acetate hydrate play an important role in the gel structure formation. Results demonstrated that the gel structure and composition can be controlled simply by adjusting the amount of acetic acid without laser irradiation, suggesting that the results obtained from this study are useful as a newly developed and simple method of preparing calcium gel with various structures.

Self-assembly of mixed-linkage glucan hydrogels formed following EG16 digestion

Mixed-linkage glucans are major components of grassy cell-walls and cereal endosperm. Recently identified plant endo-β-glucanase from the EG16 family cleaves MLGs with strong specificity towards regions with at least four sequential β(1,4)-linked glucose residues. This activity yields a low molecular-weight MLG with a repeating structure of β(1,3)-linked cellotriose that gels rapidly at concentrations as low as 1.0 % w/v. To understand the gelation mechanism, we investigated the structure and behavior using rheology, microscopy, X-ray scattering, and molecular dynamics simulations. Upon digestion, the material's rheological behavior changes from typical polymeric material to a fibrillar network behavior seen for e.g. cellulose nanofibrils. Scanning electron microscopy and confocal microscopy verifies these changes in micro- and nanostructure. Small-angle X-ray scattering shows in-solution self-assembly of MLG through ~10 nm elemental structures. Wide-angle X-ray scattering data indicate that the polymer association is similar to cellulose II, with dominant scattering at d-spacing of 0.43 nm. Simulations of two interacting glucan chains show that β(1,3)-linkages prevent the formation of tight helices that form between β(1,4)-linked d-glucan chains, leading to weaker interactions and less ordered inter-chain assembly. Overall, these data indicate that digestion drives gelation not by enhancement of interactions driving self-assembly, but by elimination of unproductive interactions hindering self-assembly.

A comprehensive review on freeze-induced deterioration of frozen egg yolks: Freezing behaviors, gelation mechanisms, and control techniques.

Over the years, the production of eggs has increased tremendously, with an estimated global egg production of 9.7 billion by 2050. Further processing of shell eggs to egg products has gained growing popularity. Liquid egg yolks, an innovative form of egg replacement, still suffer from short shelf-life issues, and freezing has been applied to maintain freshness. An undesirable phenomenon called "gelation" was found during the production of frozen egg yolks, which has attracted numerous scholars to study its mechanism and quality control methods. Therefore, we comprehensively reviewed the history of the studies on frozen egg yolks, including the production procedure, the fundamentals of freezing, the gelation mechanism, the factors affecting gelation behaviors, and the techniques to control the gelation behaviors of frozen egg yolks. Reporting the production procedure and freezing fundamentals of frozen egg yolks will give readers a better understanding of the science and technological aspects of frozen egg yolks. Furthermore, a comprehensive summary of the mechanism of egg yolk gel formation induced by freeze-thawing and relevant control techniques will provide insights to researchers and manufacturers in the field of frozen egg processing.

The impact of κ-carrageenan on the pea protein gelation by high pressure processing and the gelling mechanisms study

The transition toward sustainable and health-conscious diets has intensified plant-based proteins, particularly pea protein. This research explored the gelation mechanisms of pea protein with κ-carrageenan by high-pressure processing (HPP) as an alternative to traditional thermal methods. Suspensions containing 15% pea protein with 0.1–1% κ-carrageenan were subjected to HPP at 100–600 MPa for 5–30 min. Increasing κ-carrageenan concentration reduced the pressure required to obtain good gels, rendering HPP more energy efficient. Pea protein gels with 1% κ-carrageenan at 600 MPa demonstrated a 27-fold increase in compressive strength compared to 15% pea protein alone by HPP and over 5 times the strength of heat-induced counterparts. Gel textures could be tailored by modulating HPP conditions and κ-carrageenan concentrations. Fourier transform infrared spectroscopy, confocal laser scanning microscopy, and scanning electron microscopy characterized protein unfolding, phase separation, and network formation to study the gelation mechanisms. Results revealed that HPP induced protein tertiary structure unfolding, facilitating phase separation and uniform submicron κ-carrageenan particle distribution in the protein matrix. This, along with a more compact protein network induced by HPP, enhanced gel strength, compensating for limited cysteine in pea protein for disulfide bonds. Higher pressures intensified protein unfolding and aggregation, with κ-carrageenan particles evenly distributing into smaller particles, further strengthening gel structures. Conversely, heating-induced gelation caused more random protein aggregation, leading to coarser and weaker gel networks. This research highlights HPP's effectiveness over traditional heating methods in preparing strong pea protein gels with minimal κ-carrageenan and provides preliminary insights into tailoring HPP and κ-carrageenan for desirable gel textures.

Research progress on plant‐based glue in meat substitutes: main components, formation mechanisms, challenges, and development

SummaryThe growing recognition of environmental conservation and human well‐being has led to a surge in the advancement of plant‐based meat. These meat alternatives are similar to animal meat products regarding texture, flavour, shape, and other characteristics. These products consist of three main components: plant tissue proteins, fat mimetics, and plant‐based glues that act as binders. Since meat substitutes are subjected to high temperatures and pressures or refrigeration, the junction between the tissue proteins and fat mimetics is prone to cracking, necessitating the development of adhesives with excellent bonding characteristics. The physicochemical properties and functional applications of plant glues are currently attracting significant research attention. Plant‐based glues are essentially gels derived from substances such as proteins, polysaccharides, or various compounds. This article summarised the basic principles of gel formation, focusing on acid‐, salt‐, heat‐, and enzyme‐induced gel formation pathways, as well as the role of pH adjustment and enzyme or salt ion addition in improving their functional properties. Optimal conditions can enhance the adhesive properties of plant‐based glues. This article reviewed the types, gelation mechanisms, influencing factors, and challenges of plant‐based glues to provide a theoretical basis for research on their application potential.

Study on preparation and properties of steel slag based composite gel for mine fire prevention and extinguishing

A novel fire-preventing composite gel, mainly made from steel slag (SS) and silica fume (SF), was created for a coal mine’s spontaneous combustion. The gelation mechanism of the steel slag-based composite gel (SSG) was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (SEM). The findings suggest that SSG is generated through the processes of hydration and geopolymerization involving SS and SF. And in the alkaline milieu of a 1.5 M water glass solution, SSG manifests enhanced strength and water retention capacities. Moreover, the fire prevention and extinguishing performance of the SSG was analyzed and verified using low-temperature oxidation, thermogravimetry, and low temperature nitrogen adsorption experiment (LTNA). The SSG has proven highly effective in suppressing spontaneous coal combustion by inhibiting CO production, raising the coal oxidation temperature, and reducing the contact area between oxygen and the coal body.

Sustainable varicose vein therapy using functionalized hydrogels derived solely from livestock waste

Developing sustainable and effective treatments for chronic venous insufficiency (CVI) is crucial. In this study, we propose an innovative restorative approach utilizing hydrogels derived from the decellularized extracellular matrix (dECM) of cadaveric vascular tissues, adipose-derived stem cells (ADSCs), and gold nanoparticles (AuNPs). This therapeutic method leverages waste valorization by repurposing discarded cadaveric tissues from slaughterhouse livestock. The dECM hydrogels, enriched with ADSCs and AuNPs, offer a biocompatible scaffold that supports cellular differentiation and vascular integrity. Our approach addresses the limitations of current allo-, auto-, and xenograft methods by enhancing integration and functionality while potentially reducing costs through sustainable practices. This study explores functionalized hydrogel formulation solely generated from agri-food waste, gelation mechanisms, and preliminary cost-effectiveness, presenting a promising new avenue for treating early-stage varicose veins that can ultimately be translated to human models using discarded tissues.

High performances of cellulose nanocrystal based bicomponent supramolecular hydrogel lubricant

To improve the limitations of water-based lubricants, a novel cellulose nanocrystal based supramolecular hydrogel (CNC/x-DG/y) was prepared by mixing cellulose nanocrystal (CNC) and diglycerol (DG) into deionized water (DW). The hydrogel was characterized to determine its material ratio and gelation mechanism. When DW was fixed at 1 mL, CNC content should be no <2.4 wt% and DG content 0.1–1.3 mL. The gelification was driven by the multiple H-bond network between CNC and DG, which immobilized water molecules. The rheological performances, the anti-rust property and the volatilization behaviour of the hydrogel were further studied. The results showed that the hydrogel had satisfactory viscoelasticity, excellent thermal stability, strong creep recovery, high anti-rust performance and low volatilization rate, which were exactly its advantages for use as lubricant. A typical representative of the hydrogel, namely CNC/2.4-DG/0.1, was selected to evaluate the tribological performances, and the resulting worn surfaces were analyzed. CNC/2.4-DG/0.1 exhibited a lower friction coefficient of 0.059 and a smaller wear volume of 0.81 × 10−3 mm3, compared to DW(1 mL) + CNC(2.4 wt%) and DW(1 mL) + DG(0.1 mL). The outstanding tribological performances of CNC/2.4-DG/0.1 were reasonably attributed to the synergistic mending effect of CNC and DG and the dissipative effect of H-bonds between the two.

Development and Geometrical Considerations of Unique Conductive and Reversible Carbon-Nanotube Hydrogel without Need for Gelators.

We propose a new type of CNT hydrogel that has unique conductive and reversible characteristics. We found in previous studies that CNT dispersions became gelatinous without any gelators when a specific CNT was combined with a specific dispersant. This hydrogel has conductive properties derived mainly from the CNTs it contains; and even after gelation, it can be returned to a liquid state by ultrasonic irradiation. Furthermore, the liquid is gelable again. In this study, we prepared several types of CNTs and several types of dispersants, experimentally verified the possibility of gelation by combining them, and geometrically investigated the gelation mechanism to determine how this unique hydrogel is formed. As a result, we found that the experimental results and the theory examined in this study were consistent with the combination of materials that actually become hydrogels. We expect that this study will allow us to anticipate whether or not an unknown combination of CNTs and dispersants will also become gelatinous.

New Ureas and Amides - An Account of Recent Trends and Developments in Low Molecular Weight Gelators

Abstract: The last 20 years have witnessed major advancements in the field of supramolecular chemistry and have brought us closer to the designing of low molecular weight gelators with desired properties and applications. In that regard, amide- and ureabased gelators comprise a unique class as they are extremely versatile in terms of molecular design and offer a wide range of applications, like anion responsive materials, selective sensing of heavy metal ions, environmental remediation and many more. Both sets of compounds have similar molecular scaffolds, making them an excellent tool to determine the relative importance of the supramolecular interactions involved in the gelation process. Besides, the concept of crystal engineering can also be employed to understand the underlying mechanism of gelation by scrutinizing the interactions and supramolecular assemblies formed by these systems. In this article, we focus on various supramolecular assemblies formed by various amide and urea derivatives and their recently reported applications to establish structure-property correlation and their futuristic aspects.

Mussel‐inspired self‐assembly of silver nanoclusters into multifunctional silver aerogels for enhanced catalytic and bactericidal applications

AbstractSilver nanoclusters (AgNCs) have shown broad application prospects in catalysis, sensing, and biological fields. However, the limited stability of AgNCs has become the main challenge restricting their practical application in complex environments. Herein, a mussel‐inspired, dopamine‐assisted self‐assembly approach is reported to fabricate 3D AgNC aerogels (PDA/AgNCs), which possess significantly enhanced structural stability and synergistic functional properties. The prepared AgNC aerogels display a hierarchical network structure with an ultrafine ligament size of 10.3 ± 1.2 nm and a high specific surface area of 50.7 m2 g−1. The gelation mechanism is elucidated by in‐depth characterization and time‐lapse monitoring of the gelation process vis spectroscopic and microscopic approaches. Owing to the distinct features of aerogels and the synergistic effect of AgNCs and PDA, the fabricated aerogels can not only efficiently decolorize dyes with a faster kinetic than individual AgNCs, but also exhibit remarkable broad‐spectrum antimicrobial activity. Consequently, a conceptual water‐treatment device is established by depositing PDA/AgNC aerogels on the cotton substrate, which shows good performance in both catalytic dye degradation and bacterial killing in the flowing system. This mussel‐inspired self‐assembly strategy has great potential in developing robust AgNC‐based functional materials, which also provides a new guideline for designing sophisticated materials with integrated functions and synergistic properties.

A bioactive composite sponge based on biomimetic collagen fibril and oxidized alginate for noncompressible hemorrhage and wound healing

The study focuses on developing a bioactive shape memory sponge to address the urgent demand for short-term rapid hemostasis and long-term wound healing in noncompressible hemorrhage cases. A composite sponge was created by spontaneously generating pores and double cross-linking under mild conditions using biomimetic collagen fibril (BCF) and oxidized alginate (OA) as natural backbone, combined with an inert calcium source (Ca) from CaCO3-GDL slow gelation mechanism. The optimized BCF/OACa (5/5) sponge efficiently absorbed blood after compression and recovered to its original state within 11.2 ± 1.3 s, achieving physical hemostatic mechanism. The composite sponge accelerated physiological coagulation by promoting platelet adhesion and activation through BCF, as well as enhancing endogenous and exogenous hemostatic pathways by Ca2+. Compared to commercial PVA expanding hemostatic sponge, the composite sponge reduced bleeding volume and shortened hemostasis time in rat liver injury pick and perforation wound models. Additionally, it stimulated fibroblast migration and differentiation, thus promoting wound healing. It is biodegradable with low inflammatory response and promotes granulation tissue regeneration. In conclusion, this biocomposite sponge provides multiple hemostatic pathways and biochemical support for wound healing, is biologically safe and easy to fabricate, process and use, with significant potential for clinical translation and application.

Elucidating the rheological and thermal properties of mixed fish and pork skin gelatin gels: Effects of cooling conditions and incubation times

Gelatin is an important hydrocolloid in food and biotechnological applications. There are two basic sources of gelatins; mammalian and fish-derived gelatins, but fish gelatins are less appreciated due to their weak gel properties. Hence, to reinforce the gel properties of fish gelatin, mixtures of gelatins are used. In this study, the mixtures of cold-water ocean fish scale (OFS) and pork skin (PS) gelatin were studied via rheological measurements, micro differential scanning calorimetry (DSC), and particle tracking at different cooling conditions and incubation times to understand the gelation mechanism and the network structure of the gels. The rheological and micro-DSC measurements provide a detailed understanding of the gelation mechanism of gelatin gels under different cooling conditions while particle tracking revealed the local physical properties of the gels. A single or two-step melting was demonstrated in the mixed gelatin gels depending on the cooling conditions suggesting that the aggregation of PS in the mixtures influences the physical and thermal properties of the gels. Under rapid cooling, co-aggregation of OFS and PS chains is considered to cause a single-step melting of the mixed gels. Under gradual cooling, conversely, the PS may form aggregates independently before the OFS. This is evidenced by a two-step decrease in moduli and two clear endothermic peaks in the micro-DSC measurement. Particle tracking further reveals information on the local physical properties of pure and mixed gelatin gels on reheating, indicating that the local structures of mixed gels resemble those of pure PS gels. This suggests that mixed OFS and PS gels may form a cooperative aggregation, thereby improving the physical and thermal properties of the mixed gelatin gels.