Alginate Research Articles

Effect of inulin on structural, physicochemical, and in vitro gastrointestinal tract release properties of core-shell hydrogel beads as a delivery system for vitamin B12

In this study, core-shell hydrogel beads were developed as a controlled-release delivery system for vitamin B12. Vitamin B12-loaded microgels (MG) were prepared using gellan gum (GG). Core-shell hydrogel beads were produced by incorporating MG into pea protein isolate (PPI) and sodium alginate (AL) matrix filled/coated with different concentrations (0 %, 1 %, 3 %, 5 %, and 10 %) of inulin (IN). Based on XRD analysis, MG was successfully incorporated into core-shell hydrogel beads. In FE-SEM and FT-IR analyses, the smoother surface and denser structure of the beads were observed as IN concentration increased due to hydrogen bonds between IN and the beads. The encapsulation efficiency increased from 68.64 % to 82.36 % as IN concentration increased from 0 % to 10 %, respectively. After exposure to simulated oral and gastric conditions, core-shell hydrogel beads exhibited a lower cumulative release than MG, and a more sustained release was observed as IN concentration increased in simulated intestinal conditions.

Pickering emulsions based on ovalbumin‐ferulic acid‐sodium alginate supramolecular hydrogels: application to cookies replacing margarine

SummaryMargarine contains trans fatty acids, which have been linked to adverse effects on human health. It is therefore of the utmost importance to develop superior margarine substitutes for use in baked foods. The protein‐polyphenol‐polysaccharide ternary supramolecular system displays remarkable stability and can be utilised in the formulation of emulsions for partial margarine replacement. The aim of this study was to examine the stability of an ovalbumin (OVA)‐ferulic acid (FA)‐sodium alginate (SA) ternary supramolecular emulsion with varying water‐to‐oil ratios. The emulsion was evaluated for its potential as a substitute for margarine in cookies. The findings revealed that the specific emulsion instability of the system initially increased and subsequently decreased with an increase in corn oil content, reaching an optimal point of stability and dispersibility at a water‐to‐oil ratio of 5:11. As the emulsion was incorporated into the cookie dough at levels ranging from 0% to 100% margarine, the viscoelasticity of the dough was enhanced and the hardness was reduced. As the emulsion content increased in place of margarine, the cookies exhibited visible cracks on the surface, accompanied by an increase in hardness, baking loss rate and a notable change in colour. The cookies demonstrated the optimal quality when the emulsion content was 40%.

Development of biochromic paper strips from cellulose nanocrystals and anthocyanin extract from pomegranate (Punica granatum L.) for colorimetric determination of urea

AbstractAn anthocyanin (ACN) spectroscopic probe was extracted and immobilized into a matrix of cellulose nanocrystals (CNC)/urease enzyme to create a colorimetric nanocomposite film sensor. The ACN@CNC composite is a disposable molecular biosensor that uses urease as a catalyst, ACN as a molecular probe, and CNC as a probe carrier with a high surface area. The ACN spectroscopic probe was isolated from the pomegranate peel (Punica granatum L.). A mordant was applied to fix ACN onto CNC by forming nanoparticles (6–14 nm) of mordant/ACN (M/ACN) complexation. CNC showed diameters in the range of 11–21 nm, and crystal lengths of 55–130 nm. Under acid/base conditions, the ACN probe solution in distilled water exhibited a reversible color change, as shown by the UV–Vis absorption spectra. In order to create a biocomposite film, CNC were reinforced with a sodium alginate biopolymer. Upon exposure to urea in an aqueous solution, the ACN@CNC film biosensor changes color from purple (598 nm) to white (432 nm). The detection limit of urea was determined at 25–450 ppm. Various methods were utilized to investigate the morphological properties of CNC and ACN@CNC films.

Creating ultra-strong and recyclable green plastics from marine-sourced alginate-chitosan nanowhisker nanocomposites for controlled release urea fertilizer

In response to the pressing environmental challenge posed by petroleum-derived plastics, the development of green plastics derived from all-biomass nanocomposites offers promising solutions. However, conventional nanocomposites often prioritize enhanced stiffness at the expense of flexibility. We introduce sodium alginate (SA)/chitosan nanowhisker (CSW) nanocomposites, derived entirely from marine-sourced all-biomass, to create ultra-strong and flexible green plastics. Through the synergistic interaction between SA and CSW, these nanocomposites demonstrate simultaneous stiffening and toughening, overcoming the traditional trade-off. Two key mechanisms contribute: geometric reinforcement from the needle-like structure of CSW and electrostatic reinforcement at the interface between oppositely charged CSW and SA. Compared to control SA, the SA/CSW nanocomposites exhibit remarkable enhancements in tensile modulus, strength, and stretchability, by 49%, 85%, and 55%, respectively (7.6 GPa, 223.3 MPa, 14.7%). Cellulose nanocrystals, serving as a control, only stiffen the nanocomposites, adhering to the typical trade-off. Biodegradability in compost can be tailored based on the type of nanofillers. Due to the water resistance of CSW, SA/CSW nanocomposites are proven effective for the controlled release of urea fertilizer in agricultural applications. With recyclability and superior mechanical properties, these marine-sourced green plastics offer a sustainable alternative to conventional plastics, promising significant impact in the eco-plastic industry.

Fabrication of pH-responsive whey protein/sodium alginate composite hydrogel beads for theaflavins

In this study, pH-responsive whey protein (WP)/sodium alginate (SA) composite hydrogel beads using the ionic gelation method were described and evaluated for their potential as delivery carriers for theaflavin (TF). Fourier transform infrared spectroscopy (FTIR) confirmed the interaction between WP and SA in the hydrogel beads is driven primarily by the strong intermolecular interactions, including hydrogen bonding and electrostatic attractions. The swelling ratio of the beads possesses good pH dependence and pH reversibility, effectively preventing the release of TF in the gastric environment. The encapsulation efficiency (EE) of TF in hydrogel beads ranged from 94.995 ± 0.03 to 95.709 ± 0.14, with a loading capacity (LC) of 27–34 mg/g. In in vitro digestion simulations, owing to the pH responsiveness, hydrogel beads released minimal TF throughout gastric digestion and were fully released in the intestine phase. Additionally, the release kinetics of TF from the beads were further examined in a simulated intestinal environment. These findings suggest that the hydrogel bead system is a promising carrier for encapsulating TF, offering a theoretical and experimental basis for its future application in the food industry.

In Vitro Study of Cyano-Phycocyanin Release from Hydrogels and Ex Vivo Study of Skin Penetration.

This study explored the most suitable materials for incorporating cyano-phycocyanin (C-PC) into hydrogels, focusing on maintaining the C-PC's long-term structural integrity and stabilityNext, the release of C-PC from the hydrogels and its skin penetration were investigated. A series of 1% (w/w) C-PC hydrogels was prepared using various gelling agents and preservatives. Spectrophotometric measurements compared the amount of C-PC in the hydrogels to the initially added amount. After selecting the most suitable gelling agent and preservative, two C-PC hydrogels, with and without propylene glycol (PG) (Sigma-Aldrich, St. Louis, MO, USA), were produced for further testing. In vitro release studies utilized modified Franz-type diffusion cells, while ex vivo skin-permeation studies employed Bronaugh-type cells and human skin. Confocal laser scanning microscopy analyzed C-PC accumulation in the skin. The findings demonstrated that sodium alginate (Sigma-Aldrich, St. Louis, MO, USA), hydroxyethyl cellulose (HEC) (Sigma-Aldrich, St. Louis, MO, USA), and SoligelTM (Givaudan, Vernier, Switzerland) are effective biopolymers for formulating hydrogels while maintaining C-PC stability. After 6 h, C-PC release from the hydrogel containing PG was approximately 10% or 728.07 (±19.35) μg/cm2, significantly higher than the nearly 7% or 531.44 (±26.81) μg/cm2 release from the hydrogel without PG (p < 0.05). The ex vivo qualitative skin-permeation study indicated that PG enhances C-PC penetration into the outermost skin layer. PG's ability to enhance the release of C-PC from the hydrogel, coupled with its capacity to modify the skin barrier ex vivo, facilitates the penetration of C-PC into the stratum corneum.

Green-synthesized silver nanoparticles immobilized on graphene oxide for fruit preservation in alginate films

In this study, silver nanoparticles were synthesized by redox method using tea polyphenol as a reducing agent. These nanoparticles were then immobilized within sodium alginate (SA) composite films using graphene oxide (Go), resulting in films with enhanced food preservation capabilities. Initially, the synthesized silver nanoparticles underwent characterization through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). This characterization affirmed the successful synthesis of silver nanoparticles. Subsequently, the impact of silver nanoparticles and graphene oxide on the properties of the SA composite films was investigated. The SA composite films were analyzed barrier, mechanical, thermal stability, and functional properties. The findings revealed that the inclusion of silver nanoparticles immobilized in Go augmented the tensile strength (23.6 %), degradation temperature of the films, reduced water vapor permeability, and exhibited antioxidant properties (4.16 %–42.09 %), and antimicrobial activities against Escherichia coli and Staphylococcus aureus (19.79–20.37 times). The graphene oxide immobilizes the silver nanoparticles, thereby reducing the release concentration. Packaging blueberry fruits with the SA composite film impregnated with Go-immobilized silver nanoparticles reduced weight loss and wrinkle index and this enhanced blueberry fruit shelf life. Thus, this work presents a novel approach to preparing antimicrobial packaging films for post-harvest fruit preservation.

Poly(3-Hexylthiophene) Based Bioelectronic Interface Using Conducting Nanofibers (CNFs) for the Sensitive Determination of Folate Receptor Cancer Biomarkers in Human Plasma

Folate receptors (FRs) are important biomarkers that can indicate the presence of various cancers. Sensitive and accurate detection of FRs is crucial for early cancer diagnosis and treatment. The current methods of FRs detection have high cost, potential cytotoxicity, and complex production by relying on metallic nanomaterials, or have low electrical conductivity and sensitivity such as biopolymers. To address these challenges, a new approach using conducting nanofibers (CNFs) as bioelectronic surface was developed. A composite of sodium alginate (SA), a bio-friendly polymer, poly-ethylene oxide (PEO), an antifouling polymer, and poly(3-hexylthiophene) (P3HT), a semi-conducting organic polymer nanofiber was synthesized, with folic acid conjugated to the CNFs as a biorecognition element to target (FRs). The electrochemical and electrical properties were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy in a solution containing both a redox marker and free redox species. The CNFs exhibit electroactivity in buffer solution without a redox marker, owing to the electronic properties of the P3HT of EIS readout. The obtained biosensor significantly improved sensitivity, enabling the detection of FRs with a limit of detection (LOD) of 0.12 pM in human plasma, the high sensitivity compared to all previous approaches and a 25-fold improvement compared to the sensor described in our previous study, with improved selectivity. Additionally, the results showed a good biocompatibility toward MCF-7 breast cancer cells, which opens the way for their use as theragnostic nanoprobes for cancer cells diagnosis and therapy. This study provided a simple, low cost and sensitive analytical approach for folate receptor detection.

Alginate-modified ZnO anti-planktonic and anti-biofilm nanoparticles for infected wound healing

Bacterial infections is one of the main factors delaying the wound healing, which has become a serious challenge for healthcare systems. Zinc oxide nanoparticles (ZnO NPs), which show broad-spectrum and excellent antibacterial activity, tend to aggregate easily and therefore hardly penetrate into bacterial biofilms, showing limited anti-biofilm properties. Herein, alginate (ALG) modified ZnO NPs (ZnO@ALG) were prepared via the combination of mussel-inspired method and “thiol-Michael” click reaction, which showed excellent dispersion and biocompatibility. Besides, the interactions between ZnO@ALG and bacteria was much better than that of ZnO NPs, and makes the bacteria produced more reactive oxygen species (ROS) than bare ZnO NPs. The anti-planktonic activity of ZnO@ALG (250 μg/mL) could reach almost 100 %, which was 2–3 times higher than that of bare ZnO NPs. In addition, the ZnO@ALG could significantly accelerate the healing of S. aureus infected wounds, and the wound healing rate of ZnO@ALG group was about 79.2 %, which was significantly higher than that of ZnO NPs (∼65.8 %). This study demonstrates that the ZnO@ALG holds a great potential in the anti-planktonic and anti-biofilm fields, and the ALG-modification method can be an effective strategy to enhance the antibacterial properties of nanomaterials.

Slow-release antimicrobial preservation composite coating based on bamboo-derived xylan–A new way to preserve blueberry freshness

In recent years, the biocompatibility and environmental friendliness of xylan-based materials have demonstrated great potential in the field of food packaging and coatings. In this study, the cationized xylan based composite coating (CXC) was developed using a hybrid system of cationic-modified bamboo xylan (CMX) and sodium alginate (SA) combined with thyme oil microcapsules (TM). The optimized CXC-B was composed of 1.27 % TM, 2.42 % CMX (CMX: SA = 3:2), and 96.31 % distilled water. When applied to the surface of a blueberry, the CXC-B treatment extended the ambient storage time of the fruit to 10 days while substantially reducing its morbidity (P < 0.05) and protecting its texture, flavor, and nutritional integrity. The resulting composite coating provides a promising solution to the problem of blueberry perishability during ambient storage.

Poison Turned Panacea: Arsenic Trioxide Loaded Hydrogel for Inhibiting Scar Formation in Wound Healing.

Without intervention, the natural wound healing process can often result in scarring, which can have detrimental effects on both the physical and mental well-being of patients. Therefore, it is crucial to develop biomaterials that can promote healing without scarring. Regulating the Yes-associated protein-1/PDZ-binding motif (YAP/TAZ) signaling pathway is possible to reduce excessive fibrosis of fibroblasts and proliferation of vascular endothelial cells, ultimately impacting scar formation. Arsenic trioxide (ATO), an ancient drug with medicinal and toxic properties, has shown promise in regulating this pathway. An ATO-loaded hydrogel dressing (ATO@CS/SA) was created to facilitate scarless wound healing, utilizing chitosan (CS) and sodium alginate (SA) to prevent direct contact of ATO with the wound tissue and minimize potential side effects. In vitro studies demonstrated that low concentrations of ATO did not impact cell viability and even promoted proliferation and migration. Co-culturing the hydrogel with fibroblasts and vascular endothelial cells led to decreased expression levels of YAP and TAZ. Animal studies over a 90-day period revealed significant inhibition of scar formation with this system. Histological experiments further confirmed that the decreased expression of YAP and TAZ was responsible for this outcome. In conclusion, when administered at the appropriate dose, ATO can be repurposed from a traditional poison to a therapeutic agent, effectively suppressing excessive cell fibrosis and blood vessel proliferation and offering a novel approach to scar-free treatment.

Investigation on novel chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) and its potential application for organic dyes removal from aqueous solution

Chitosan, a natural polysaccharide, has attracted considerable attention as an environmentally friendly and highly efficient adsorbent for dye removal. It is usually produced by deacetylation or partial deacetylation of chitin. However, conventional sources of chitin and chitosan are limited, prompting the need for alternative sources with improved adsorption capabilities. Herein, this study focuses on exploring a novel chitin and chitosan source derived from the dung beetle and evaluates its potential for organic dye removal from aqueous solutions. The research involves the extraction and characterization of chitin and chitosan from dung beetle Heteronitis castelnaui (Harold, 1865) using various analytical techniques, including SEM, FT-IR, TGA, XRD, NMR, deacetylation degree and elemental analysis. The chitosan obtained was used for the formation of hydrogels with sodium alginate via cross-linking with calcium chloride. And then the prepared hydrogels were evaluated for its adsorption capacity through batch adsorption experiments using methylene blue as a model pollutant. The adsorption capacity for methylene blue was 1294.3 mg/g at room temperature with solution pH = 12, MB concentration of 1800 mg/L. Furthermore, the kinetics of the adsorption process were analyzed using pseudo-first-order and pseudo-second-order models to understand the rate of adsorption. The maximum adsorption capacities were determined using Langmuir and Freundlich isotherm models. This study provides valuable insights for the development of sustainable dye adsorption technologies, specifically investigating a novel chitosan source derived from the dung beetle.

Simultaneous nitrogen and phosphorus removal by immobilized bacterial particles of denitrifying phosphorus accumulating microorganisms and its application

Enterobacter cloacae G, a novel denitrifying phosphorus-accumulating bacterial strain, was isolated from anaerobic sludge tank of a wastewater treatment plant used for pig farms. It was discovered that a pH of 7, a temperature of 30°C, an initial phosphorus concentration of 8 mg/L, and a C/N ratio of 10 were the strain's ideal growth conditions. To ensure the stability of strain G in wastewater treatment, strain G was immobilized by 5 % polyvinyl alcohol, 2 % sodium alginate, and 0.6 g of biochar and crosslinked for 9 h in 4 % calcium chloride saturated boric acid solution via an orthogonal test. After the immobilized microspheres were introduced into the sequencing batch reactor (SBR), the nitrate and phosphate removal rates achieved were 89.36 % and 65.53 %, respectively, with a hydraulic retention time (HRT) of 8 hours, a pH of 7.5, and a C/N ratio of 4.5. The immobilized microspheres containing strain G demonstrated potential for the treatment of nitrogen-rich and phosphorus-rich wastewater.

Adsorption behavior and mechanism of NH2-MIL-101(Cr)@COFs@SA composite adsorbent for tetracycline removal

Herein, we employed a rational approach to develop a hydrogel composite material by encapsulating NH2-MIL-101(Cr)/covalent organic frameworks (COFs) in sodium alginate (SA) to effectively capture of tetracycline (TC). Experimental tests and various characterizations (including Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron spectroscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS)) confirmed that the NH2-MIL-101(Cr)@COFs@SA composite exhibited a more robust, multilayer pore structure with abundant active functional groups. Under conditions of 298 K and pH = 7, the NH2-MIL-101(Cr)@COFs@SA adsorbent demonstrated remarkable TC adsorption capability, achieving a removal rate of 96.38 % in 120 min and a qmax of 252.6 mg/g at 298 K by Langmuir model. Kinetic analysis indicated that the interaction between TC and NH2-MIL-101(Cr)@COFs@SA follows a pseudo-second-order model, suggesting that chemisoption governs the process. The Langmuir model and thermodynamic analysis suggested that TC adsorption follows a monolayer sorption pattern and is spontaneous and exothermic. Even in the presence of other ions, NH2-MIL-101(Cr)@COFs@SA maintained high efficiency for TC adsorption, demonstrating superior selectivity. NH2-MIL-101(Cr)@COFs@SA demonstrated remarkable recyclability, with only a minimal reduction in the removal efficiency (85.5 % and 142 mg/g) after 10 cycles of adsorption and regeneration. Various analytical techniques, including FTIR spectroscopy, SEM, EDX, XPS, and density functional theory (DFT) calculations of adsorption energy were used to elucidate the TC adsorption mechanisms by NH2-MIL-101(Cr)@COFs@SA. The adsorption process primarily involved π-π stacking, hydrogen bonding, electrostatic interactions, and complexation.

Targeted delivery of cisplatin magnetic nanoparticles for diagnosis and treatment of nasopharyngeal carcinoma

Rapid advances in nanotechnology are paving the way for innovative breakthroughs in overcoming the current limitations in the clinical treatment of cancer and other prevalent diseases plaguing mankind. Magnetic nanoparticles composed of iron oxide (Fe3O4) are a novel class of nanoparticles that are receiving increasing attention in the field of cancer therapy. To address the inherent limitations, bare Fe3O4 can be functionalized, polymerized, assembled, or combined with other functional materials to produce a range of smart nanoplatforms suitable for tumor therapy. In this paper, we present a unique multifunctional therapeutic nanoplatform centered on aldehyde-oxidized sodium alginate-stabilized iron oxide nanoparticles (NPs) designed for T2-weighted magnetic resonance (MR) imaging. Sodium alginate oxide and ferric oxide nanoparticles were prepared respectively, and the two particles were mixed in a certain molar ratio to form a complex, which was coupled to target polypeptide GE11 by Schiff base reaction, and finally supported by cisplatin through coordination complexation. The prepared magnetic nanoparticles (hereinafter referred to as GE11-CDDP-ASA@Fe3O4) have an average diameter of 152.9 nm, and have good colloidal stability and cytocompatibility. The distinctive structure and composition of GE11-CDDP-ASA@Fe3O4 contribute to its excellent MRI imaging performance, positioning it as a nano platform suitable for enhancing the efficacy of combination therapy in tumor treatment. This is of great significance for translational nanomedicine applications.

Curcumin-Loaded Liposomes in Gel Protect the Skin of Mice against Oxidative Stress from Photodamage Induced by UV Irradiation.

Prolonged exposure to ultraviolet (UV) irradiation can cause oxidative stress in the skin, accompanied by rapid immunosuppressive effects, resulting in a peroxidation reaction throughout the body. Curcumin (Cur), as the bioactive compound of turmeric, is a natural polyphenol with potent antioxidant properties but is often overlooked due to its poor solubility and low bioavailability. In this study, curcumin-loaded liposomes in a sodium alginate gel complex preparation were designed to improve the bioavailability of curcumin and to study its preventive effect on photodamage. Cur-loaded liposomes (Cur-L), Cur-loaded gel (Cur-G) based on an alginate matrix, and curcumin-loaded liposomes in gel (Cur-LG) were prepared, and their antioxidant effects and drug diffusion abilities were evaluated. The antioxidant capacity of Cur, Cur-L, Cur-G, and Cur-LG was also studied in a mouse model of photodamage. Cur had the highest antioxidant activity at about 4 mg/mL. Cur-LG at this concentration showed antioxidant effects during 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and H2O2 experiments. During the UV light damage test, Cur-LG demonstrated the ability to effectively neutralize free radicals generated as a result of lipid peroxidation in the skin, serum, and liver, thereby enhancing the overall activity of superoxide dismutase (SOD). In conclusion, using Cur-LG may protect against epidermal and cellular abnormalities induced by UV irradiation.

Amoxicillin-laded sodium alginate/cellulose nanocrystals/polyvinyl alcohol composite nanonetwork sponges with enhanced wound healing and antibacterial performance

Wound healing is a complex process and reuires a long repair process. Poor healing effect is normally a challenge for wound healing. Designing sponge dressings with drug-assisted therapy, good breathability, and multiple functional structures effectively promotes wound healing. In this work, a flexible amoxicillin-laded (AMX) sodium alginate (SA)/cellulose nanocrystals (CNCs)/ polyvinyl alcoho (PVA) (SA/CNCs/PVA-AMX, SCP-AMX) wound dressing was designed and built with an excellent porous structure, suitable porosity, and anti-bacterial properties for promoting wound tissue reparation. The porous structure of the wound dressing was fabricated by freeze-thawing cyclic and freeze-dried molding process. This wound dressing exhibited a 3D porous structure for soft-tissue-engineering application, including high porosity (84.2%), swelling ratio (1513%), tensile strength (1.79 MPA), and flexibility. With the inhibition zones of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) being 1.96 and4.58 cm, respectively, this wound dressing demonstrated good antibacterial activity against E. coli and S. aureus. More importantly, wound healing assay in vivo indicates that SCP-AMX could inhibit wound infection, promote collagen deposition, reduce inflammation, and accelerate granulation tissue and wound healing. Thus, the reported wounding dressings present excellent biocompatibility, high antibacterial activities, and excellent biosafety with great potential in wound healing applications.

Three-dimensional breast cancer tumor models based on natural hydrogels: a review.

Breast cancer is the most common cancer in women and one of the deadliest cancers worldwide. According to the distribution of tumor tissue, breast cancer can be divided into invasive and non-invasive forms. The cancer cells in invasive breast cancer pass through the breast and through the immune system or systemic circulation to different parts of the body, forming metastatic breast cancer. Drug resistance and distant metastasis are the main causes of death from breast cancer. Research on breast cancer has attracted extensive attention from researchers. In vitro construction of tumor models by tissue engineering methods is a common tool for studying cancer mechanisms and anticancer drug screening. The tumor microenvironment consists of cancer cells and various types of stromal cells, including fibroblasts, endothelial cells, mesenchymal cells, and immune cells embedded in the extracellular matrix. The extracellular matrix contains fibrin proteins (such as types I, II, III, IV, VI, and X collagen and elastin) and glycoproteins (such as proteoglycan, laminin, and fibronectin), which are involved in cell signaling and binding of growth factors. The current traditional two-dimensional (2D) tumor models are limited by the growth environment and often cannot accurately reproduce the heterogeneity and complexity of tumor tissues in vivo. Therefore, in recent years, research on three-dimensional (3D) tumor models has gradually increased, especially 3D bioprinting models with high precision and repeatability. Compared with a 2D model, the 3D environment can better simulate the complex extracellular matrix components and structures in the tumor microenvironment. Three-dimensional models are often used as a bridge between 2D cellular level experiments and animal experiments. Acellular matrix, gelatin, sodium alginate, and other natural materials are widely used in the construction of tumor models because of their excellent biocompatibility and non-immune rejection. Here, we review various natural scaffold materials and construction methods involved in 3D tissue-engineered tumor models, as a reference for research in the field of breast cancer.

Biocompatibility and antimicrobial effect of demineralised dentin matrix hydrogel for dental pulp preservation.

Regeneration of dentin and preserving pulp vitality are essential targets for vital pulp therapy. Our study aimed to evaluate a novel biomimetic pulp capping agent with increased dentin regenerative activities. To produce demineralised dentin matrix (DDM) particles, human extracted teeth were ground and treated with ethylene diamine tetra-acetic acid solution. DDM particles were added to sodium alginate and this combination was dripped into a 5% calcium chloride to obtain DDM hydrogel (DDMH). The eluants of both DDMH and mineral trioxide aggregate (MTA) were tested using an MTT assay to detect their cytotoxic effect on dental pulp stem cells (DPSC). Collagen-I (COL-I) gene expression was analysed on DPSC exposed to different dilutions of pulp capping material eluants by real-time quantitative polymerase chain reaction. Acridine orange staining was used to monitor the cell growth over the tested materials. Agar diffusion assay was utilised to test the antibacterial effect of DDMH and MTA compared to controls. MTT assay revealed that neat eluates of DDMH promoted DPSC viability. However, neat eluates of MTA were cytotoxic on DPSC after 72h of culture. Moreover, DPSC were capable of growth and attached to the surface of DDMH, while they showed a marked reduction in their number when cultured on the MTA surface for one week, as shown by the acridine orange stain. In DPSC cultured with DDMH eluates, the COL-I gene was overexpressed compared to those cultured with MTA eluants. DDMH had significant antimicrobial activity in comparison to MTA after 24h incubation. This in vitro study showed that DDMH could be an alternative pulp capping agent for regenerative endodontics.

Enhanced oxygen barrier properties of sodium alginate coatings in humid environments: ionic crosslinking of sodium alginate by calcium ions released from calcium hydrogen phosphate and calcium carbonate

Enhanced oxygen barrier properties of sodium alginate coatings in humid environments: ionic crosslinking of sodium alginate by calcium ions released from calcium hydrogen phosphate and calcium carbonate