Alginate/gelatin blend films and their properties for drug controlled release

Influence of copper ion cross-linked CMC-PVA film on cell viability and cell proliferation study

In this study, films composed of carboxymethyl cellulose and polyvinyl alcohol were fabricated using the solution casting method. Citric acid (4 %) was employed as a cross-linking agent, while glycerol (3 %) as a plasticizer. Cupric chloride (CuCl2·2H2O) was used for cross-linking at concentrations 0.5 %, 1 %, and 3 % over different times. The cross-linking with copper ions led to a noticeable reduction in elasticity, with the breaking strain ranging from 17.9 %-52.9 %, and increased the contact angle. The ion hydration phenomenon increased the swelling ratio of the films. Fourier-transform infrared (FTIR) spectroscopy confirmed the esterification reactions and copper ion cross-linking with sodium carboxymethyl cellulose (Na-CMC). The films showed antibacterial activity against Staphylococcus aureus and Escherichia coli. The ion-released mechanism followed was the non-Fickian super case-II type. The concentration and duration of cross-linking significantly influenced the cell viability and proliferation. FE-SEM analysis revealed that effective concentrations of CuCl2.2H2O were 0.5 % and 1 %, and the cross-linking times were 5-15 min, facilitating cell attachment and proliferation. Films are non-adhesive with water vapor permeation 800-900 g/m2/day. These results indicate the potential use of the films in treating second-degree burn wounds with low to medium exudate levels. This study provides valuable insights into the development of copper-infused materials for advanced wound healing applications.

Multifunctional and novelty green composite film containing sodium alginate, chitosan, rice husk and curcumin

Foodborne diseases are a global public health issue, with their causes often originating from lapses in food production or transportation leading to food contamination. Therefore, food packaging plays a crucial role in preserving the safety and quality of food. In pursuit of sustainable development, this study aims to utilize agricultural waste-derived functional mesoporous silica nanoparticles in combination with biodegradable molecules to create food packaging films. Through recycling and the use of environmentally friendly green films, the goal is to achieve sustainability and the objectives of green chemistry. The study anticipates the production of biodegradable films and the testing of their antibacterial capabilities, antioxidant properties, biocompatibility, and film stress coefficients. This research will provide robust support for advancing green packaging technology to address the challenges of global food safety and environmental sustainability. The experiment is divided into two parts. The first part involves the synthesis of multifunctional mesoporous silica nanoparticles with antibacterial properties derived from rice husk (Rice husk mesoporous silica nanoparticles, rMSN) as nano-fillers. These nanoparticles are surface modified with a biodegradable polymer, chitosan (Chi), that interacts with the material. Natural extract curcumin (Cur), known for its antioxidant capabilities, is loaded into the pores, and the material's inherent antibacterial properties are utilized. The second part involves blending the material with the natural polymer sodium alginate (SA) to form a film (rMSN-Chi@Cur/Alg film). The film's thickness, stress strength, antibacterial, and antioxidant capabilities are tested to ensure the material possesses antibacterial and antioxidant properties.

Thermo-controlled microfluidic generation of monodisperse alginate microspheres based on external gelation

Droplet-based microfluidic systems have received much attention as promising tools for fabricating monodisperse microspheres of alginate solutions with high accuracy and reproducibility. The immediate and simple ionotropic gelation of alginate, its biocompatibility, and its tunability of mechanical properties make it a favorable hydrogel in the biomedical and tissue engineering fields. In these fields, micron-sized alginate hydrogel spheres have shown high potential as cell vehicles and drug delivery systems. Although on-chip microfluidic gelation of the produced alginate droplets is common, several challenges remain. Complicated chemical and microfabrication processes are required, and the risk of microchannel clogging is high. In the current study, we present an easy-to-use microfluidic external gelation process to produce highly spherical and monodisperse microspheres from very low-concentrated alginate-RGD solution [0.5% (w/v)]. To accomplish this, gelatin, a thermo-sensitive and inexpensive biomaterial, was incorporated into the alginate solution as a sacrificial biomaterial that mediates the off-chip external gelation of the alginate with Ca2+, and avoids droplet coalescence. Utilizing the methodology mentioned above, we successfully generated monodisperse alginate microspheres (AMs) with diameters ranging from 27 μm to 46 μm, with a coefficient of variation of 0.14, from a mixture of Arg-Gly-Asp (RGD)-modified very low viscosity alginate and gelatin. These RGD-AMs were used as microcarriers for human umbilical vein endothelial cells. The described easy-to-use and cost-effective microfluidic off-chip external gelation strategy exhibits comparable advantages to on-chip external gelation and demonstrates superiority over the latter since clogging is impossible.

The Impact of Green Physical Crosslinking Methods on the Development of Sericin-Based Biohydrogels for Wound Healing

Silk sericin (SS)-based hydrogels show promise for wound healing due to their biocompatibility, moisture regulation, and cell proliferation properties. However, there is still a need to develop green crosslinking methods to obtain non-toxic, absorbent, and mechanically strong SS hydrogels. This study investigated the effects of three green crosslinking methods, annealing treatment (T), exposure to an absolute ethanol vapor atmosphere (V.E), and water vapor (V.A), on the physicochemical and mechanical properties of SS and poly (vinyl alcohol) (PVA) biohydrogels. X-ray diffraction and Fourier-transform infrared spectroscopy were used to determine chemical structures. Thermal properties and morphological changes were studied through thermogravimetric analysis and scanning electron microscopy, respectively. The water absorption capacity, mass loss, sericin release in phosphate-buffered saline (PBS), and compressive strength were also evaluated. The results showed that physical crosslinking methods induced different structural transitions in the biohydrogels, impacting their mechanical properties. In particular, V.A hydrogen presented the highest compressive strength at 80% deformation owing to its compact and porous structure with crystallization and bonding sites. Moreover, both the V.A and T hydrogels exhibited improved absorption capacity, stability, and slow SS release in PBS. These results demonstrate the potential of green physical crosslinking techniques for producing SS/PVA biomaterials for wound healing applications.

Chitosan-Coated Liposome Formulations for Encapsulation of Ciprofloxacin and Etoposide

Cancer and bacterial infections rank among the most significant global health threats. accounting for roughly 25 million fatalities each year. This statistic underscores the urgent necessity for developing novel drugs, enhancing current treatments, and implementing systems that boost their bioavailability to achieve superior therapeutic outcomes. Liposomes have been recognised as effective carriers; nonetheless, they encounter issues with long-term stability and structural integrity, which limit their pharmaceutical applicability. Chitosomes (chitosan-coated liposomes) are generally a good alternative to solve these issues. This research aims to demonstrate the effective individual encapsulation of ciprofloxacin (antibacterial, hydrophilic) and etoposide (anticancer, hydrophobic), within chitosomes to create more effective drug delivery systems (oral administration for ciprofloxacin, parenteral administration for etoposide). Thus, liposomes and chitosomes were prepared using the thin-film hydration technique and were characterised through ATR-FTIR, Dynamic Light Scattering (DLS), zeta potential, and release profiling. In both cases, the application of chitosomes enhanced long-term stability in size and surface charge. Chitosome-encapsulated ciprofloxacin formulations exhibited a slower and sustained release profile, while the combined effect of etoposide and chitosan showed heightened efficacy against the glioblastoma cell line U373. Therefore, coating liposomes with chitosan improved the encapsulation system's properties, resulting in a promising method for drug delivery.

Bacterial nanocellulose/calcium alginate hydrogel for the treatment of burns

PURPOSE

Bacterial cellulose (BC) has shown high capacity for the treatment of wounds and burns, providing a moisty environment. Calcium alginate can be associated with BC to create gels that aid in wound debridement and contribute to appropriate wound healing. This study is aimed at characterizing and evaluating the use of bacterial cellulose/alginate gel in skin burns in rats.

METHODS

Cellulose and cellulose/alginate gels were compared regarding the capacity of liquid absorption, moisture, viscosity, and potential cytotoxicity. The 2nd degree burns were produced using an aluminum metal plate (2.0cm) at 120ºC for 20s on the back of rats. The animals were divided into non-treated, CMC(Carboxymethylcellulose), Cellulose(CMC with bacterial cellulose), and Cellulose/alginate(CMC with bacterial cellulose and alginate). The animals received topical treatment 3 times/week. Biochemical (MPO, NAG and oxidative stress), histomorphometry and immunohistochemical assays (IL-1β IL-10 and VEGF) were conducted on the 14th, 21st, 28th, and 35th days.

RESULTS

Cellulose/Alginate gel showed higher absorption capacity and viscosity compared to Cellulose gel, with no cytotoxic effects. Cellulose/alginate presented lower MPO values, a higher percentage of IL-10, with greater and balanced oxidative stress profile.

CONCLUSIONS

The use of cellulose/alginate gel reduced neutrophils and macrophage activation and showed greater anti-inflammatory response, which can contribute to healing chronic wounds and burns.

Multifunctional Eco-Friendly Adsorbent Cryogels Based on Xylan Derived from Coffee Residues

Agricultural and animal farming practices contribute significantly to greenhouse gas (GHG) emissions such as NH3, CH4, CO2, and NOx, causing local environmental concerns involving health risks and water/air pollution. A growing need to capture these pollutants is leading to the development of new strategies, including the use of solid adsorbents. However, commonly used adsorbent materials often pose toxicity and negative long-term environmental effects. This study aimed to develop responsive eco-friendly cryogels using xylan extracted from coffee parchment, a typical residue from coffee production. The crosslinking in cryogels was accomplished by "freeze-thawing" and subsequent freeze-drying. Cryogels were characterized in terms of morphology by using scanning electron microscopy, porosity, and density by the liquid saturation method and also moisture adsorption and ammonia adsorption capacity. The analysis showed that the porosity in the cryogels remained around 0.62-0.42, while the apparent densities varied from 0.14 g/cm3 to 0.25 g/cm3. The moisture adsorption capacity was the highest at the highest relative humidity level (80%), reaching 0.25-0.43 g of water per gram of sample; the amount of water adsorbed increased when the xylan content in the cryogel increased up to 10% w/v, which was consistent with the hygroscopic nature of xylan. The ammonia adsorption process was modeled accurately by a pseudo-second-order equation, where the maximum adsorption capacity in equilibrium reached 0.047 mg NH3/g when xylan reached 10% w/v in cryogels, indicating a chemisorption process. The cryogels under investigation hold promise for ammonia adsorption applications and GHG separation, offering a sustainable alternative for gas-capturing processes.

Designing an antimicrobial film for wound applications incorporating bacteriophages and ε-poly-l-lysine

Alginate-based dressings have been shown to promote wound healing, leveraging the unique properties of alginate. This work aimed to develop and characterize flexible individual and bilayered films to deliver bacteriophages (phages) and ε-Poly-l-lysine (ε-PLL). Films varied in different properties. The moisture content, swelling and solubility increased with higher alginate concentrations. The water vapour permeability, crucial in biomedical films to balance moisture levels for effective wound healing, reached optimal levels in bilayer films, indicating these will be able to sustain an ideal moist environment. The bilayer films showed improved ductility (lower tensile strength and increased elongation at break) compared to individual films. The incorporated phages maintained viability for 12 weeks under vacuum and refrigerated conditions, and their release was sustained and gradual. Antibacterial immersion tests showed that films with phages and ε-PLL significantly inhibited Pseudomonas aeruginosa PAO1 growth (>3.1 Log CFU/cm2). Particle release was influenced by the swelling degree and diffusional processes within the polymer network, providing insights into controlled release mechanisms for particles of varying size (50 nm to 6 μm) and charge. The films developed, demonstrated modulated release capabilities for active agents, and may show potential as controlled delivery systems for phages and wound healing adjuvants.

A review on natural biopolymers in external drug delivery systems for wound healing and atopic dermatitis

Despite the advantages of topical administration in the treatment of skin diseases, current marketed preparations face the challenge of the skin's barrier effect, leading to low therapeutic effectiveness and undesirable side effects. Hence, in recent years the management of skin wounds, the main morbidity-causing complication in hospital environments, and atopic dermatitis, the most common inflammatory skin disease, has become a great concern. Fortunately, new, more effective, and safer treatments are already under development, with chitosan, starch, silk fibroin, agarose, hyaluronic acid, alginate, collagen, and gelatin having been used for the development of nanoparticles, liposomes, niosomes and/or hydrogels to improve the delivery of several molecules for the treatment of these diseases. Biocompatibility, biodegradability, increased viscosity, controlled drug delivery, increased drug retention in the epidermis, and overall mitigation of adverse effects, contribute to an effective treatment, additionally providing intrinsic antimicrobial and wound healing properties. In this review, some of the most recent success cases of biopolymer-based drug delivery systems as part of nanocarriers, semi-solid hydrogel matrices, or both (hybrid systems), for the management of skin wounds and atopic dermatitis, are critically discussed, including composition and in vitro, ex vivo and in vivo characterization, showing the promise of these external drug delivery systems.

3D-bioprinted alginate-based bioink scaffolds with β-tricalcium phosphate for bone regeneration applications

Background/purpose

3D-printed bone tissue engineering is becoming recognized as a key approach in dentistry for creating customized bone regeneration treatments fitting patients bone defects requirements. 3D bioprinting offers an innovative method to fabricate detailed 3D structures, closely emulating the native bone micro-environment and better bone regeneration. This study aimed to develop an 3D-bioprintable scaffold using a combination of alginate and β-tricalcium phosphate (β-TCP) with the Cellink® BioX printer, aiming to advance the field of tissue engineering.

Materials and methods

The physical and biological properties of the resulting 3D-printed scaffolds were evaluated at 10 %, 12 %, and 15 % alginate combined with 10 % β-TCP. The scaffolds were characterized through printability, swelling behavior, degradability, and element analysis. The biological assessment included cell viability, alkaline phosphatase (ALP) activity.

Results

10 % alginate/β-TCP 3D printed at 25 °C scaffold demonstrated the optimal condition for printability, swelling capability, and degradability of cell growth and nutrient diffusion. Addition of β-TCP particles significantly improved the 3D printed material viscosity over only alginate (P < 0.05). 10 % alginate/β-TCP enhanced MG-63 cell's proliferation (P < 0.05) and alkaline phosphatase activity (P < 0.001).

Conclusion

This study demonstrated in vitro that 10 % alginate/β-TCP bioink characteristic for fabricating 3D acellular bioprinted scaffolds was the best approach. 10 % alginate/β-TCP bioink 3D-printed scaffold exhibited superior physical properties and promoted enhanced cell viability and alkaline phosphatase activity, showing great potential for personalized bone regeneration treatments.

Addition of Bone-Marrow Mesenchymal Stem Cells to 3D-Printed Alginate/Gelatin Hydrogel Containing Freeze-Dried Bone Nanoparticles Accelerates Regeneration of Critical Size Bone Defects

A 3D-printed biodegradable hydrogel, consisting of alginate, gelatin, and freeze-dried bone allograft nanoparticles (npFDBA), is developed as a scaffold for enhancing cell adhesion, proliferation, and osteogenic differentiation when combined with rat bone marrow mesenchymal stem cells (rBMSCs). This composite hydrogel is intended for the regeneration of critical-sized bone defects using a rat calvaria defect model. The behavior of rBMSCs seeded onto the scaffold is evaluated through scanning electron microscope, MTT assays, and quantitative real-time PCR. In a randomized study, thirty rats are assigned to five treatment groups: 1) rBMSCs-loaded hydrogel, 2) rBMSCs-loaded FDBA microparticles, 3) hydrogel alone, 4) FDBA alone, and 5) an empty defect serving as a negative control. After 8 weeks, bone regeneration is assessed using H&E, Masson's trichrome staining, and immunohistochemistry. The 3D-printed hydrogel displays excellent adhesion, proliferation, and differentiation of rBMSCs. The rBMSCs-loaded hydrogel exhibits comparable new bone regeneration to the rBMSCs-loaded FDBA group, outperforming other groups with statistical significance (P-value < 0.05). These findings are corroborated by Masson's trichrome staining and osteocalcin expression. The rBMSCs-loaded 3D-printed hydrogel demonstrates promising potential for significantly enhancing bone regeneration, surpassing the conventional clinical approach (FDBA).

A novel film based on a cellulose/sodium alginate/gelatin composite activated with an ethanolic fraction of Boswellia sacra oleo gum resin

Boswellia sacra and its derivatives exhibit notable bioactive properties, which have been the subject of extensive scientific research; however, their potential applications in food packaging remain largely untapped. In the current study, cellulose, sodium alginate, and gelatin composite edible films were fabricated with the addition of different concentrations (0.2% and 0.3%) of the ethanolic fraction of Boswellia sacra oleo gum resin (BSOR). The resultant films were examined for their physical, chemical, mechanical, barrier, optical, and antioxidant properties. Moreover, the films were characterized using Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to study the impact of incorporating BSOR on the morphological, crystalline, and chemical properties of the films. The addition of BSOR increased the film thickness (0.026-0.08 mm), water vapor permeability (0.210-0.619 (g.mm)/(m2.h.kPa), and the intensity of the yellow color (3.01-7.20) while reducing the values of both tensile strength (6.67-1.03 MPa) and elongation at break (83.50%-48.81%). SEM and FTIR analysis confirmed the interaction between the BSOR and film-forming components. The antioxidant properties of the edible films were significantly increased with the addition of BSOR. The comprehensive findings of the study demonstrated that BSOR possesses the potential to serve as an efficient natural antioxidant agent in the fabrication of edible films.

Evaluation of antimicrobial photodynamic action of a pluronic and pectin based film loaded with methylene blue against methicillin resistantStaphylococcus aureus

Antimicrobial wound dressings play a crucial role in treatment of wound infections. However, existing commercial options fall short due to antibiotic resistance and the limited spectrum of activity of newly emerging antimicrobials against bacteria that are frequently encountered in wound infections. Antimicrobial photodynamic therapy (aPDT) is very promising alternative therapeutic approach against antibiotic resistant microbes such as methicillin resistantStaphylococcus aureus (MRSA). However, delivery of the photosensitizer (PS) homogeneously to the wound site is a challenge. Though polymeric wound dressings based on synthetic and biopolymers are being explored for aPDT, there is paucity of data regarding theirin vivoefficacy. Moreover, there are no studies on use of PS loaded, pluoronic (PL) and pectin (PC) based films for aPDT. We report development of a polymeric film for potential use in aPDT. The film was prepared using PL and PC via solvent casting approach and impregnated with methylene blue (MB) for photodynamic inactivation of MRSAin vitroandin vivo. Atomic force microscopic imaging of the films yielded vivid pictures of surface topography, with rough surfaces, pores, and furrows. The PL:PC ratio (2:3) was optimized that would result in an intact film but exhibit rapid release of MB in time scale suitable for aPDT. The film showed good antibacterial activity against planktonic suspension, biofilm of MRSA upon exposure to red light. Investigations on MRSA infected excisional wounds of mice reveal that topical application of MB loaded film for 30 min followed by red light exposure for 5 min (fluence; ∼30 J cm-2) or 10 min (fluence; ∼60 J cm-2) reduces ∼80% or ∼92% of bioburden, respectively. Importantly, the film elicits no significant cytotoxicity against keratinocytes and human adipose derived mesenchymal stem cells. Taken together, our data demonstrate that PS-loaded PL-PC based films are a promising new tool for treatment of MRSA infected wounds.

Biofabrication methods for reconstructing extracellular matrix mimetics

In the human body, almost all cells interact with extracellular matrices (ECMs), which have tissue and organ-specific compositions and architectures. These ECMs not only function as cellular scaffolds, providing structural support, but also play a crucial role in dynamically regulating various cellular functions. This comprehensive review delves into the examination of biofabrication strategies used to develop bioactive materials that accurately mimic one or more biophysical and biochemical properties of ECMs. We discuss the potential integration of these ECM-mimics into a range of physiological and pathological in vitro models, enhancing our understanding of cellular behavior and tissue organization. Lastly, we propose future research directions for ECM-mimics in the context of tissue engineering and organ-on-a-chip applications, offering potential advancements in therapeutic approaches and improved patient outcomes.

Laser-induced graphene on cross-linked sodium alginate

Laser-induced graphene (LIG) possesses desirable properties for numerous applications. However, LIG formation on biocompatible substrates is needed to further augment the integration of LIG-based technologies into nanobiotechnology. Here, LIG formation on cross-linked sodium alginate is reported. The LIG is systematically investigated, providing a comprehensive understanding of the physicochemical characteristics of the material. Raman spectroscopy, scanning electron microscopy with energy-dispersive x-ray analysis, x-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy techniques confirm the successful generation of oxidized graphene on the surface of cross-linked sodium alginate. The influence of laser parameters and the amount of crosslinker incorporated into the alginate substrate is explored, revealing that lower laser speed, higher resolution, and increased CaCl2content leads to LIG with lower electrical resistance. These findings could have significant implications for the fabrication of LIG on alginate with tailored conductive properties, but they could also play a guiding role for LIG formation on other biocompatible substrates.

Magnetic Hydrogel Beads as a Reusable Adsorbent for Highly Efficient and Rapid Removal of Aluminum: Characterization, Response Surface Methodology Optimization, and Evaluation of Isotherms, Kinetics, and Thermodynamic Studies

Biopolymers such as alginate and gelatin have attracted much attention because of their exceptional adsorption properties and biocompatibility. The magnetic hydrogel beads produced and used in this study had a core structure composed of magnetite nanoparticles and gelatin and a shell structure composed of alginate. The combination of the metal-ion binding ability of alginate and the mechanical strength of gelatin in magnetic hydrogel beads presents a new approach for the removal of metal from water sources. The beads were designed for aluminum removal and fully characterized using various methods, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, microcomputed tomography, and dynamic mechanical analysis. Statistical experimental designs were employed to optimize the parameters of the adsorption and recovery processes. Plackett-Burman Design, Box-Behnken Design, and Central Composite Design were used for identifying the significant factors and optimizing the parameters of the adsorption and recovery processes, respectively. The optimum parameters determined for adsorption are as follows: pH: 4, contact time: 30 min, adsorbent amount: 600 mg; recovery time: reagent 1 M HNO3; and contact time: 40 min. The adsorption process was described by using the Langmuir isotherm model. It reveals a homogeneous bead surface and monolayer adsorption with an adsorption capacity of 5.25 mg g-1. Limit of detection and limit of quantification values were calculated as 4.3 and 14 μg L-1, respectively. The adsorption process was described by a pseudo-second-order kinetic model, which assumes that chemisorption is the rate-controlling mechanism. Thermodynamic studies indicate that adsorption is spontaneous and endothermic. The adsorbent was reusable for 10 successive adsorption-desorption cycles with a quantitative adsorption of 98.2% ± 0.3% and a recovery of 99.4% ± 2.6%. The minimum adsorbent dose was determined as 30 g L-1 to achieve quantitative adsorption of aluminum. The effects of the inorganic ions were also investigated. The proposed method was applied to tap water and carboy water samples, and the results indicate that magnetic hydrogel beads can be an effective and reusable bioadsorbent for the detection and removal of aluminum in water samples. The recovery values obtained by using the developed method were quantitative and consistent with the results obtained from the inductively coupled plasma optical emission spectrometer.

A Biodegradable, Adhesive, and Stretchable Hydrogel and Potential Applications for Allergic Rhinitis and Epistaxis

Bioadhesive hydrogels have attracted considerable attention as innovative materials in medical interventions and human-machine interface engineering. Despite significant advances in their application, it remains critical to develop adhesive hydrogels that meet the requirements for biocompatibility, biodegradability, long-term strong adhesion, and efficient drug delivery vehicles in moist conditions. A biocompatible, biodegradable, soft, and stretchable hydrogel made from a combination of a biopolymer (unmodified natural gelatin) and stretchable biodegradable poly(ethylene glycol) diacrylate is proposed to achieve durable and tough adhesion and explore its use for convenient and effective intranasal hemostasis and drug administration. Desirable hemostasis efficacy and enhanced therapeutic outcomes for allergic rhinitis are accomplished. Biodegradation enables the spontaneous removal of materials without causing secondary damage and minimizes medical waste. Preliminary trials on human subjects provide an essential foundation for practical applications. This work elucidates material strategies for biodegradable adhesive hydrogels, which are critical to achieving robust material interfaces and advanced drug delivery platforms for novel clinical treatments.

Fabrication of triple-crosslinked gelatin/alginate hydrogels for controlled release applications

Hydrogels have been demonstrated as smart drug carriers to recognize the tumor microenvironment for cancer treatment, where the dynamic crosslinks in the hydrogel network contribute to the stimuli-responsive features but also result in poor stability and weak mechanical property of the hydrogels. Here, phenylboronic acid-grafted polyethyleneimine (PBA-PEI)-modified gelatin (PPG) was synthesized to crosslink alginate dialdehyde (ADA) through imine bonds and boronate ester bonds, and then calcium ions (Ca2+) were added to introduce the third calcium-carboxylate crosslinking in the network to form the triple-crosslinked PPG/ADA-Ca2+ hydrogels. Given the three types of dynamic bonds in the network, PPG/ADA-Ca2+ hydrogels possessed a self-healing manner, stimuli-responsiveness, and better mechanical properties compared to single- or double-crosslinked hydrogels. The controlled release capability of PPG/ADA-Ca2+ hydrogels was also demonstrated, showing the encapsulated molecules can be rapidly released from the hydrogel network in the presence of hydrogen peroxide while the release rate can be slowed down at acidic pH. Furthermore, PPG/ADA-Ca2+ hydrogels presented selected cytotoxicity and drug delivery to cancer cells due to the regulated degradation by the cellular microenvironment. Taken together, PPG/ADA-Ca2+ hydrogels have been demonstrated as promising biomaterials with multiple desirable properties and dynamic features to perform controlled molecule release for biomedical applications.

Optimization of the Green Extraction of Red Araçá (Psidium catteyanum Sabine) and Application in Alginate Membranes for Use as Dressings

In this research, the aim was to introduce innovation to the pharmaceutical field through the exploration of an underutilized plant matrix, the red araçá, along with the utilization of sodium alginate for the development of membranes designed for active topical dressings. Within this context, optimal extraction conditions were investigated using the central composite rotational statistical design (CCRD) to obtain a red araçá epicarp extract (RAEE) rich in bioactive compounds utilizing the maceration technique. The extract acquired under the optimized conditions (temperature of 66 °C and a hydroalcoholic solvent concentration of 32%) was incorporated into a sodium alginate matrix for the production of active membranes using a casting method. Characterization of the membranes revealed that the addition of the extract did not significantly alter its morphology. Furthermore, satisfactory results were observed regarding mechanical and barrier properties, as well as the controlled release of phenolic compounds in an environment simulating wound exudate. Based on these findings, the material produced from renewable matrices demonstrates the promising potential for application as a topical dressing within the pharmaceutical industry.

Nanocurcumin and viable Lactobacillus plantarum based sponge dressing for skin wound healing

Curcumin loaded solid lipid nanoparticles (CSLNs) and probiotic (Lactobacillus plantarum UBLP-40; L. plantarum) were currently co-incorporated into a wound dressing. The combination with manifold anti-inflammatory, anti-infective, analgesic, and antioxidant properties of both curcumin and L. plantarum will better manage complex healing process. Recent reports indicate that polyphenolics like curcumin improve probiotic effects. Curcumin was nanoencapsulated (CSLNs) to improve its bioprofile and achieve controlled release on the wound bed. Bacteriotherapy (probiotic) is established to promote wound healing via antimicrobial activity, inhibition of pathogenic toxins, immunomodulation, and anti-inflammatory actions. Combination of CSLNs with probiotic enhanced (560%) its antimicrobial effects against planktonic cells and biofilms of skin pathogen, Staphylococcus aureus 9144. The sterile dressing was devised with selected polymers, and optimized for polymer concentration, and dressing characteristics using a central composite design. It exhibited a swelling ratio of 412 ± 36%, in vitro degradation time of 3 h, optimal water vapor transmission rate of 1516.81 ± 155.25 g/m2/day, high tensile strength, low-blood clotting index, case II transport, and controlled release of curcumin. XRD indicated strong interaction between employed polymers. FESEM revealed a porous sponge like meshwork embedded with L. plantarum and CSLNs. It degraded and released L. plantarum, which germinated in the wound bed. The sponge was stable under refrigerated conditions for up to six months. No translocation of probiotic from wound to the internal organs confirmed safety. The dressing exhibited faster wound closure and lowered bioburden in the wound area in mice. This was coupled with a decrease in TNF-α, MMP-9, and LPO levels; and an increase in VEGF, TGF-β, and antioxidant enzymes such as catalase and GSH, establishing multiple healing pathways. Results were compared with CSLNs and probiotic-alone dressings. The dressing was as effective as the silver nanoparticle-based marketed hydrogel dressing; however, the cost and risk of developing resistance would be much lower currently.

In situ forming alginate/gelatin hybrid hydrogels containing doxorubicin loaded chitosan/AuNPs nanogels for the local therapy of breast cancer

In this study, pH-sensitive in situ gelling hydrogels based on oxidized alginate and gelatin-containing doxorubicin (DOX) loaded chitosan/gold nanoparticles (CS/AuNPs) nanogels were fabricated via Schiff-base bond formation. The obtained CS/AuNPs nanogels indicated a size distribution of about 209 nm with a zeta potential of +19.2 mV and an encapsulation efficiency of around 72.6 % for DOX. The study of the rheological properties of hydrogels showed that the value of G' is higher than G″ for all hydrogels, which confirms the elastic behavior of hydrogels in the applied frequency range. The rheological and texture analysis demonstrated the higher mechanical properties of hydrogels containing β-GP and CS/AuNPs nanogels. The release profile of DOX after 48 h indicates the 99 % and 73 % release amount at pH = 5.8 and pH = 7.4, respectively. MTT cytotoxicity study showed that the prepared hydrogels are cytocompatible on MCF-7 cells. By the Live/Dead assay, it was demonstrated that the cultured cells on DOX-free hydrogels were almost alive in the presence of CS/AuNPs nanogels. However, the hydrogel-containing drug and free DOX in the same concentration caused high death of MCF-7 cells as expected, which showed the potential of the developed hydrogels for application in the local treatment of breast cancer.

Composite films of sodium alginate and konjac glucomannan incorporated with tea polyphenols for food preservation

At present, food waste has become a serious issue and the use of petroleum-based food packaging films has resulted in a series of potential hazards. Therefore, more attention has been focused on the development of new food packaging materials. The polysaccharide-based composite film loaded with active substances considered to be an excellent preservative material. A novel packaging film based on sodium alginate and konjac glucomannan (SA-KGM) blended with tea polyphenols (TP) was prepared in the present study. The excellent microstructure of films was shown by atomic force microscopy (AFM). It was indicated by FTIR spectra that the components could interact with each other through hydrogen bonds, which was also confirmed by molecular docking simulation. Meanwhile, the mechanical properties, barrier property, oxidation property, antibacterial activity, and stability of the structure of the TP-SA-KGM film were significantly improved. The AFM images and results of molecular docking simulation indicated that TP could affect the cell wall of bacteria by acting with peptidoglycan. Finally, the film showed excellent preservation effects in both beef and apples, which suggested that TP-SA-KGM film could be a novel bioactive packaging material with wide application potential in food preservation.

Nd Recovery from Wastewater with Magnetic Calcium Alginate ((1,4)-β-d-Mannuronic Acid and α-L-Guluronic Acid) Hydrogels

In this study, a magnetic adsorbent material was produced, by environmentally friendly and inexpensive precursor materials, to clean wastewater that may result from primary and secondary rare earth metal (REM) production. Then, the absorption of Nd³⁺ ions from wastewater was done and this process's kinetic and isotherm models were developed. Thus, the removal of Nd³⁺ from wastewater with magnetic materials was accomplished, and then, this precious metal was recovered by using different acid media. First, Fe sub-micron particles were successfully produced by the polyol method. To increase the stability of Fe-based particles, their surfaces were covered with an oxide layer, and the average thickness was determined as 16 nm. The synthesized Fe particles were added into the calcium alginate beads and then coated with chitosan to increase the pH stability of the gels. The chemical composition of the gels was determined by Fourier transform infrared spectroscopy, the thermal properties were determined by differential scanning calorimetry, and the magnetic properties were determined by vibrating-sample magnetometer analysis. The magnetic saturation of the hydrogels was 0.297 emu/g. After the production of magnetic calcium alginate hydrogels, Nd³⁺ ion removal from wastewater was done. Wastewater was cleaned with 94.22% efficiency. The kinetic models of the adsorption study were derived, and isotherm studies were done. Adsorption reaction fitted different kinetic models at different time intervals and the Freundlich isotherm model. The effect of pH, temperature, and solid-liquid ratio on the system was determined and the thermodynamic constants of the system were calculated. After the adsorption studies, Nd³⁺ ions were regenerated in different acid environments and achieved an 87.48% efficiency value. The removal of Nd³⁺ ions from wastewater was carried out with high efficiency, the gels obtained as a result of adsorption were regenerated with high efficiency by using acid media, and it was predicted that the gels could be reused. This study is thought to have reference results not only for the removal of REM from wastewater by magnetic adsorption materials but also for the adsorption of heavy metals from wastewater.

Polymer-Based Nanostructures for Pancreatic Beta-Cell Imaging and Non-Invasive Treatment of Diabetes

Diabetes poses major economic, social, and public health challenges in all countries worldwide. Besides cardiovascular disease and microangiopathy, diabetes is a leading cause of foot ulcers and lower limb amputations. With the continued rise of diabetes prevalence, it is expected that the future burden of diabetes complications, early mortality, and disabilities will increase. The diabetes epidemic is partly caused by the current lack of clinical imaging diagnostic tools, the timely monitoring of insulin secretion and insulin-expressing cell mass (beta (β)-cells), and the lack of patients' adherence to treatment, because some drugs are not tolerated or invasively administrated. In addition to this, there is a lack of efficient topical treatment capable of stopping the progression of disabilities, in particular for treating foot ulcers. In this context, polymer-based nanostructures garnered significant interest due to their tunable physicochemical characteristics, rich diversity, and biocompatibility. This review article emphasizes the last advances and discusses the prospects in the use of polymeric materials as nanocarriers for β-cell imaging and non-invasive drug delivery of insulin and antidiabetic drugs in the management of blood glucose and foot ulcers.

Preparation and Characterization of Multilayer pH-Responsive Hydrogel Loaded Ganoderma lucidum Peptides

To develop a safe, targeted, and efficient assembly of a stable polypeptide delivery system, in this work, chitosan, sodium alginate, and sodium tripolyphosphate were used as materials for the preparation of hydrogels. M-SCT hydrogels were prepared by ionic gelation and the layer-by-layer (LBL) method. The composite hydrogels exhibited excellent pH sensitivity and Ganoderma lucidum peptides (GLP) loading capacity. The prepared hydrogels were characterized and evaluated. The internal three-dimensional network structure of the hydrogel was observed by scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy confirmed the electrostatic interactions among the components. X-ray diffraction (XRD) was used to observe the crystal structure of the hydrogel. The maximum peptide encapsulation efficiency was determined to be 81.73%. The digestion stability and thermal stability of M-SCT hydrogels loaded GLP were demonstrated to be improved. The amount of peptides released from the GLP/M-SCT-0.75 hydrogels in simulated gastric fluid was lower than 30%. In addition, the ABTS assays showed that the free radical scavenging ability of the GLP/M-SCT-0.75 hydrogels confirmed the efficacy of the hydrogels in retaining the antioxidant activity of GLP. The study suggested the M-SCT-0.75 hydrogels had a great deal of potential as a peptide carrier for oral delivery.

pH-induced complex coacervation of fish gelatin and carboxylated chitosan: phase behavior and structural properties

The aim of this study was to investigate the phase behavior and structural properties of fish gelatin complex coacervation with carboxylated chitosan as a function of pH by varying the amount of carboxylated chitosan added (0-0.25%, w/v) while keeping the fish gelatin concentration constant at 0.667% (w/v). Zeta potential indicated that electrostatic interaction drove the complex coalescence of fish gelatin and carboxylated chitosan to form soluble or insoluble complexes. The turbidity of the fish gelatin-carboxylated chitosan complex system was greatest at a carboxylated chitosan concentration of 0.2%. UV and fluorescence spectroscopy indicated that the carboxylated chitosan changed the tertiary conformation of fish gelatin. Circular dichroism showed that complexation of fish gelatin with carboxylated chitosan resulted in a shift from the α-helix to the β-sheet structure of fish gelatin. In particular, at pH 5, the fish gelatin complexed with carboxylated chitosan had a disordered structure. X-ray diffraction and scanning electron microscopy of the composite coacervates both investigated that electrostatic interaction between the two replaced molecular interaction within the carboxylated chitosan to form a new lamellar porous structure. These findings may in future enable the use of fish gelatin-carboxylated chitosan complex systems in the design of new food matrices.

3D Scaffolds Fabrication via Bicomponent Microgels Assembly: Process Optimization and In Vitro Characterization

In the last decade, different technological approaches have been proposed for the fabrication of 3D models suitable to evaluate in vitro cell response. Among them, electro fluid dynamic atomization (EFDA) belonging to the family of electro-assisted technologies allows for the dropping of polysaccharides and/or proteins solutions to produce micro-scaled hydrogels or microgels with the peculiar features of hydrogel-like materials (i.e., biocompatibility, wettability, swelling). In this work, a method to fabricate 3D scaffolds by the assembly of bicomponent microgels made of sodium alginate and gelatin was proposed. As first step, optical and scanning electron microscopy with the support of image analysis enabled to explore the basic properties of single blocks in terms of correlation between particle morphology and process parameters (i.e., voltage, flow rate, electrode gap, and needle diameter). Chemical analysis via ninhydrin essays and FTIR analysis confirmed the presence of gelatin, mostly retained by physical interactions into the alginate network mediated by electrostatic forces. In vitro tests confirmed the effect of biochemical signals exerted by the protein on the biological response of hMSCs cultured onto the microgels surface. Hence, it is concluded that alginate/gelatin microgels assemblies can efficiently work as 3D scaffolds able to support in vitro cells functions, thus providing a friendly microenvironment to investigate in vitro cell interactions.

Cyclic enrichment of chromium based on valence state transformation in metal-free photocatalytic reductive imprinted composite hydrogel

Cr (VI) exists in anion form and can be reduced to positive charged Cr (III) under certain conditions. Can positive charged Cr (III) be continually used for absorbing Cr (VI) to achieve cyclic accumulation of chromium? In this paper, an ion imprinting material for adsorption of Cr (VI) was prepared by dispersing polypyrrole (PPy) in a gelatin/chitosan (Gel/CS) hydrogel network, named Gel/CS/PPy. Based on the conversion of Cr (VI) to Cr (III), a cyclic enrichment process including adsorption-photoreduction-fixation-readsorption of Cr (VI) was established in Gel/CS/PPy hydrogel. The composition and structure of the Gel/CS/PPy were analyzed by scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetric (TGA), texture analyzer (Universal TA), zeta potential and ultraviolet-visible-near infrared spectra (UV-vis-NIR). The conversion of Cr (VI) and Cr (III) and its promoting effect on readsorption were verified by XPS. The results showed that Gel/CS/PPy has good adsorption capacity for Cr (VI) and excellent photocatalytic ability to reduce Cr (VI) to Cr (III). Cr (III)-loaded Gel/CS/PPy can be further used to adsorb Cr (VI) and showed good adsorption efficiency even after four cycles. The optimal operating condition for Cr (VI) adsorption is pH = 3; 2 g/L dose of Gel/CS/PPy; and the adsorption capacity of Cr (VI) was about 106.8 mg/g after six adsorption cycles. Since Gel/CS/PPy is composed of organic components, high purity chromium can be recovered by simple calcination method later. Therefore, the synthesized Gel/CS/PPy has great potential in the practical application of low concentration Cr (VI) treatment in water.

Bioinspired Injectable Self-Healing Hydrogel Sealant with Fault-Tolerant and Repeated Thermo-Responsive Adhesion for Sutureless Post-Wound-Closure and Wound Healing

Hydrogels with multifunctionalities, including sufficient bonding strength, injectability and self-healing capacity, responsive-adhesive ability, fault-tolerant and repeated tissue adhesion, are urgently demanded for invasive wound closure and wound healing. Motivated by the adhesive mechanism of mussel and brown algae, bioinspired dynamic bonds cross-linked multifunctional hydrogel adhesive is designed based on sodium alginate (SA), gelatin (GT) and protocatechualdehyde, with ferric ions added, for sutureless post-wound-closure. The dynamic hydrogel cross-linked through Schiff base bond, catechol-Fe coordinate bond and the strong interaction between GT with temperature-dependent phase transition and SA, endows the resulting hydrogel with sufficient mechanical and adhesive strength for efficient wound closure, injectability and self-healing capacity, and repeated closure of reopened wounds. Moreover, the temperature-dependent adhesive properties endowed mispositioning hydrogel to be removed/repositioned, which is conducive for the fault-tolerant adhesion of the hydrogel adhesives during surgery. Besides, the hydrogels present good biocompatibility, near-infrared-assisted photothermal antibacterial activity, antioxidation and repeated thermo-responsive reversible adhesion and good hemostatic effect. The in vivo incision closure evaluation demonstrated their capability to promote the post-wound-closure and wound healing of the incisions, indicating that the developed reversible adhesive hydrogel dressing could serve as versatile tissue sealant.

Intermolecular Interactions in the Formation of Polysaccharide-Gelatin Complexes: A Spectroscopic Study

Gelatin, due to its gelling and stabilizing properties, is one of the widely used biopolymers in biotechnology, medicine, pharmaceuticals, and the food industry. One way to modify the characteristics of gelatin is molecular modification by forming non-covalent polyelectrolyte complexes with polysaccharides based on the self-organization of supramolecular structures. This review summarizes recent advances in the study of various types and the role of intermolecular interactions in the formation of polysaccharide-gelatin complexes, and conformational changes in gelatin, with the main focus on data obtained by spectroscopic methods: UV, FT-IR, and 1H NMR spectroscopy. In the discussion, the main focus is on the complexing polysaccharides of marine origin-sodium alginate, κ-carrageenan, and chitosan. The prospects for creating polysaccharide-gelatin complexes with desired physicochemical properties are outlined.

Preparation and Characterization of Natural Silk Fibroin Hydrogel for Protein Drug Delivery

In recent years, hydrogels have been widely used as drug carriers, especially in the area of protein delivery. The natural silk fibroin produced from cocoons of the Bombyx mori silkworm possesses excellent biocompatibility, significant bioactivity, and biodegradability. Therefore, silk fibroin-based hydrogels are arousing widespread interest in biomedical research. In this study, a process for extracting natural silk fibroin from raw silk textile yarns was established, and three aqueous solutions of silk fibroin with different molecular weight distributions were successfully prepared by controlling the degumming time. Silk fibroin was dispersed in the aqueous solution as “spherical” aggregate particles, and the smaller particles continuously accumulated into large particles. Finally, a silk fibroin hydrogel network was formed. A rheological analysis showed that as the concentration of the silk fibroin hydrogel increased its storage modulus increased significantly. The degradation behavior of silk fibroin hydrogel in different media verified its excellent stability, and the prepared silk fibroin hydrogel had good biocompatibility and an excellent drug-loading capacity. After the protein model drug BSA was loaded, the cumulative drug release within 12 h reached 80%. We hope that these investigations will promote the potential utilities of silk fibroin hydrogels in clinical medicine.

Waste-derived biomaterials as building blocks in the biomedical field

Recent developments in the biomedical arena have led to the fabrication of innovative biomaterials by utilizing bioactive molecules obtained from biological wastes released from fruit and beverage processing industries, and fish, meat, and poultry industries. These biological wastes that end up in water bodies as well as in landfills are an affluent source of animal- and plant-derived proteins, bio ceramics and polysaccharides such as collagens, gelatins, chitins, chitosans, eggshell membrane proteins, hydroxyapatites, celluloses, and pectins. These bioactive molecules have been intricately designed into scaffolds and dressing materials by utilizing advanced technologies for drug delivery, tissue engineering, and wound healing relevance. These biomaterials are environment-friendly, biodegradable, and biocompatible, and show excellent tissue regeneration attributes. Additionally, being cost-effective they can reduce the burden on the healthcare system as well as provide a sustainable solution to waste management. In this review, the current trends in the utilization of plant and animal waste-derived biomaterials in various biomedical fields are considered along with a separate section on their applications as xenografts.

Swelling of Multilayered Calcium Alginate Microspheres for Drug-Loaded Dressing Induced Rapid Lidocaine Release for Better Pain Control

The development of effective drug-loaded dressings has been considered a hot research topic for biomedical therapeutics, including the use of botanical compounds. For wound healing, adequate dressings can provide a good microenvironment for drug release, such as lidocaine. Biological macromolecular materials such as alginate show excellent properties in wound management. This study involves the preparation and evaluation of biocompatible multilayered-structure microspheres composed of chitosan, porous gelatin, and calcium alginate microspheres. The multilayered structure microspheres were named chitosan@ porous gelatin@ calcium alginate microspheres (CPAMs) and the drugs were rapidly released by the volume expansion of the calcium alginate microspheres. The in vitro release curve revealed that the peak release of lidocaine from CPAMs was reached within 18[Formula: see text]min. After 21[Formula: see text]min, the remaining lidocaine was then slowly released, and the active drug release was converted to a passive drug release phase. The initial release effect of lidocaine was much better than that reported in the published studies. Additionally, blood coagulation experiments showed that CPAMs coagulated blood in 60[Formula: see text]s, and the blood liquidity of the CPAMs group was worse than that of the woundplast group. Therefore, the coagulation characteristics of CPAMs were superior to the commonly used woundplast containing lidocaine healing gel. These study outcomes indicated that the CPAMs acted as fast-release dressings for faster pain control and better coagulation properties.

Alginate with citrus pectin and pterostilbene as healthy food packaging with antioxidant property

A new type of film packaging made from natural polysaccharide materials, with its environmental safety and friendliness, is considered as a potential substitute for plastics. Novel polysaccharide composite films based upon citrus pectin (CP) and sodium alginate (SA) were successfully prepared and characterized, containing pterostilbene (PTE) at various concentrations (0.2, 0.4, 0.8, 1.6, 3.2 mM). The rheological analysis displayed that all film-forming liquids performed no gelation behavior with G" > G' at low frequency and weak gelation with G" < G' at high frequency. The SA-CP films had good tensile strength (TS) and elongation at break (EB), while adding PTE as an antioxidant to the film reduced both the values. Of note, the SA-CP films with PTE had better moisture resistance than that of the pure SA-CP films, which was related to the changes of its microstructure. The increased roughness of the films containing PTE was observed by microscope. After calcium chloride cross-linking, the water solubility of the films was reduced, while its thermal stability was improved. Notably, the accretion of PTE expressively enhanced the antioxidant properties of the SA-CP films. Thus, the SA-CP composite films containing PTE could be utilized as an excellent antioxidant packaging material.

A Novel Three-Polysaccharide Blend In Situ Gelling Powder for Wound Healing Applications

In this paper, alginate/pectin and alginate/pectin/chitosan blend particles, in the form of an in situ forming hydrogel, intended for wound repair applications, have been successfully developed. Particles have been used to encapsulate doxycycline in order to control the delivery of the drug, enhance its antimicrobial properties, and the ability to inhibit host matrix metalloproteinases. The presence of chitosan in the particles strongly influenced their size, morphology, and fluid uptake properties, as well as drug encapsulation efficiency and release, due to both chemical interactions between the polymers in the blend and interactions with the drug demonstrated by FTIR studies. In vitro antimicrobial studies highlighted an increase in antibacterial activity related to the chitosan amount in the powders. Moreover, in situ gelling powders are able to induce a higher release of IL-8 from the human keratinocytes that could stimulate the wound healing process in difficult-healing. Interestingly, doxycycline-loaded particles are able to increase drug activity against MMPs, with good activity against MMP-9 even at 0.5 μg/mL over 72 h. Such results suggest that such powders rich in chitosan could be a promising dressing for exudating wounds.

Denitrification potential of sodium alginate gel beads immobilized iron-carbon, Zoogloea sp. L2, and riboflavin: Performance optimization and mechanism

A kind of gel beads loaded with iron-carbon powder (Fe-C), Zoogloea sp. L2, and riboflavin (VB2) were prepared through cross-linking of sodium alginate (SA) to establish an immobilized bioreactor. The optimal ratio of SA beads was adjusted by orthogonal experiment. The change of oxidation-reduction potential (ORP) and the concentration of Fe²⁺ and Fe³⁺ showed that the addition of VB2 as a redox mediator can promote denitrification. Under the optimal conditions (carbon to nitrogen (C/N) ratio = 2.0, pH = 7.0, and hydraulic retention time (HRT) = 8 h), the nitrate removal efficiency (NRE) of bioreactor reached 98.48% (1.99 mg L^-1h^-1). Furthermore, Fourier transform infrared spectrometer (FTIR), Fluorescence excitation-emission matrix (EEM), X-ray diffraction (XRD), and gas chromatography (GC) analysis revealed that the immobilization and denitrification of the immobilized bioreactor were excellent. High throughput sequencing also showed that Zoogloea played a vital role in nitrate removal.

Evaluating the addition of xylooligosaccharides into alginate-gelatin hydrogels

Xylooligosaccharides (XOS) are emerging prebiotic that may improve structural features of biopolymer blends. The investigation around the conformation of XOS into the matrix of alginate and gelatin clarifies the potential applications of this formulation in the food industry as texture modifiers or encapsulation systems. Structural properties verified by flow behavior, SEM, XRD, and FT-IR demonstrated that the add up to 3% XOS into the alginate-gelatin blend formed a cohesive matrix, with smaller pores and crystalline structure, confirming the potential of xylooligosaccharides hydrogels for the development of functional and synbiotic foods.

Colorimetric films based on pectin/sodium alginate/xanthan gum incorporated with raspberry pomace extract for monitoring protein-rich food freshness

Raspberry pomace extracts (RPE) with different concentrations (0.5 g/L, 1.5 g/L and 3 g/L) were incorporated into pectin/sodium alginate/xanthan gum composite film (PAX) to prepare colorimetric raspberry films (PAXR₅, PAXR₁₅ and PAXR₃₀). Fourier Transform Infrared and Scanning Electron Microscopy analysis showed RPE had good compatibility with PAX. Compared to PAX, the raspberry films had lower water vapor permeability and water swelling ratio, higher tensile strength, opacity and antioxidant capacity. The films presented a smoother surface and denser structure than PAX. Furthermore, PAXR₁₅ had an excellent discoloration at pH 1-13, especially at pH 5-10, the color changes of PAXR₁₅ from pink-red-brown-blue-dark green distinguished by the naked eyes. Therefore, it has the potential to become a pH-sensitive film used in monitoring protein-rich food freshness.

Gut Organoid as a New Platform to Study Alginate and Chitosan Mediated PLGA Nanoparticles for Drug Delivery

Intestinal organoids can be used as an ex vivo epithelial model to study different drug delivery effects on epithelial cells’ luminal surface. In this study, the impact of surface charge on the delivery of 5-ASA loaded PLGA nanoparticles into the lumen of organoids was investigated. Alginate and chitosan were used to coat the nanoparticles and provide negative and positive charges on the particles, respectively. The organoid growth and viability were not affected by the presence of either alginate- or chitosan-coated nanoparticles. It was shown that nanoparticles could be transported from the serosal side of the organoids to the lumen as the dye gradually accumulated in the lumen by day 2–3 after adding the nanoparticles to the Matrigel. By day 5, the dye was eliminated from the lumen of the organoids. It was concluded that the positively charged nanoparticles were more readily transported across the epithelium into the lumen. It may be attributed to the affinity of epithelial cells to the positive charge. Thus, the organoid can be utilized as an appropriate model to mimic the functions of the intestinal epithelium and can be used as a model to evaluate the benefits of nanoparticle-based drug delivery.

Photo/thermal response of polypyrrole-modified calcium alginate/gelatin microspheres based on helix-coil structural transition and the controlled release of agrochemicals

Responsive controlled-release systems can not only improve the efficiency of agrochemical utilization but also increase crop yield and reduce environmental pollution caused by excessive use of agrochemicals. In this paper, the helix-coil structural transition of gelatin was adopted to construct a novel stimuli-responsive controlled-release system called polypyrrole/Ca-alginate/gelatin (PPy/Ca-alginate/Gel). In PPy/Ca-alginate/Gel, Ca-alginate and gelatin form a semi-interpenetrating network in which uncross-linked gelatin can undergo a free helix-coil structural transition due to the photothermal effect of PPy. The structural transition of gelatin will lead to changes in the functional groups and microstructure of semi-interpenetrating hydrogels and furthermore achieve the release of template agrochemical molecules embedded in hydrogels. By using carbendazim as a template molecule, the photothermal conversion and controlled release of PPy/Ca-alginate/Gel were systematically studied. After 600 s of light irradiation, its temperature could be increased by 17 ℃. The release of carbendazim in microspheres reached 91.8 % after 8 h of light irradiation, while it was only 13.3 % in the dark. The results indicated that PPy/Ca-alginate/Gel have excellent controlled-release and sustained-release properties and broad application potential in agriculture.

Pectin/sodium alginate/xanthan gum edible composite films as the fresh-cut package

Due to the convenience, fresh-cut vegetables or fruits as the emerging commercial products have attracted much attention in recent years. However, the preservation of food with high quality remains a big challenge. In this study, one novel kind of edible composite film (PAX) consisted of pectin, sodium alginate (SA), and xanthan gum (XG) was well developed. The optimum concentrations for pectin and SA in PAX film based on the shearing viscosity were 6 g/L and 5 g/L, respectively. Upon this condition, the experimental results from the response surface methodology showed that the tensile strength for the optimized PAX (PAX_O) film can reach the maximum value of 29.65 MPa at the concentration of 4 g/L XG, 18 g/L glycerol, and 20 g/L CaCl₂. The corresponding elongation at break was 19.02% and the water vapor transmission rate was evaluated to be 18.12 × 10^-11 g/(m²·s·pa). Furthermore, the nanocomposites in terms of coating or films were used to keep fresh-cut potatoes, where they exhibited different efficiencies in food preservation with the order: PAX_O coating + CaCl₂ ≈ PAX_O coating > PAX_O film > sterile water. All the results indicated that the as-prepared PAX_O film or PAX_O solution could be good candidates in packaging preservation.