Development and assessment of an immobilized bacterial alliance that efficiently degrades tylosin in wastewater.

Microbial degradation of tylosin (TYL) is a safe and environmentally friendly technology for remediating environmental pollution. Kurthia gibsonii (TYL-A1) and Klebsiella pneumonia (TYL-B2) were isolated from wastewater; degradation efficiency of the two strains combined was significantly greater than either alone and resulted in degradation products that were less toxic than TYL. With Polyvinyl alcohol (PVA)-sodium alginate (SA)-activated carbon (AC) used to form a bacterial immobilization carrier, the immobilized bacterial alliance reached 95.9% degradation efficiency in 1 d and could be reused for four cycles, with > 93% degradation efficiency per cycle. In a wastewater application, the immobilized bacterial alliance degraded 67.0% TYL in 9 d. There were significant advantages for the immobilized bacterial alliance at pH 5 or 9, with 20 or 40 g/L NaCl, or with 10 or 50 mg/L doxycycline. In summary, in this study, a bacterial consortium with TYL degradation ability was constructed using PVA-SA-AC as an immobilized carrier, and the application effect was evaluated on farm wastewater with a view to providing application guidance in environmental remediation.

Synthesis of biodegradable sodium alginate-based carbon dot-nanomagnetic composite (SA-FOCD) for enhanced water remediation using ANN modelling, RSM optimization, and economic analysis.

This study involves the synthesis of a magnetic­sodium alginate bio-composite embedded with carbon dots, designed to eliminate pollutants like dyes and metal ions and tackle environmental issues. The modified particles are effectively incorporated into the biopolymers for improved adsorption and regeneration performance using an economically viable and environmentally sustainable process. The composite's surface morphology and chemical structure have been extensively characterized through various analytical techniques. It has been found that CD-modified nanoparticles demonstrate good dispersion, abundance in functional groups, and excellent adsorption performance. The adsorption process variables have been optimized using Response Surface Methodology (RSM), resulting in a maximum adsorption capacity of 232.44 mg/g achieved under optimal conditions. An Artificial Neural Network (ANN) model with a topology of 3-5-5-1 is constructed to predict the adsorption capacity of composite, exhibiting superior predictive performance. The statistical physical model was also performed to understand the adsorption mechanism and orientation of dye molecules attached to the surface of the composite. The adsorption capacity using statistical physical method was found to be 467.57 mg/g. The composite exhibits good adsorption and regeneration performance in the column adsorption study. Furthermore, a detailed cost analysis of the synthesized composite was performed, ensuring its economic viability in real-world applications.

Synthesis and bioactivity assessment of Coccinia grandis L. extract encapsulated alginate nanoparticles as an antidiabetic drug lead.

AIM: This study aimed to prepare, characterise, and evaluate the antidiabetic activity of Coccinia grandis (L.) extracts encapsulated alginate nanoparticles. METHODS: Alginate nanoparticles were prepared using the ionic gelation method and characterised by encapsulation efficiency %w/w, loading capacity %w/w, particle size analysis, zeta potential, Fourier transform infra-red spectroscopy (FTIR), and scanning electron microscopy (SEM). In vitro antidiabetic activity was also evaluated. RESULTS: Encapsulation efficiency %w/w, loading capacity %w/w, mean diameter, zeta potential of C. grandis encapsulated alginate nanoparticles ranged from 10.51 ± 0.51 to 62.01 ± 1.28%w/w, 0.39 ± 0.04 to 3.12 ± 0.11%w/w, 191.9 ± 76.7 to 298.9 ± 89.6 nm, -21.3 ± 3.3 to -28.4 ± 3.4 mV, respectively. SEM and FTIR confirmed that particles were in nano range with spherical shape and successful encapsulation of plant extracts into an alginate matrix. The antidiabetic potential of aqueous extract of C. grandis encapsulated alginate nanoparticles (AqCG-ANP) exhibited inhibition in α-amylase, α-glucosidase and dipeptidyl peptidase IV enzymes of 60.8%c/c, 19.1%c/c, and 30.3%c/c, respectively, compared to the AqCG. CONCLUSION: The AqCG-ANP exerted promising antidiabetic potential as an antidiabetic drug lead.

Assessment of calcium alginate gels as wall materials for encapsulation systems.

BACKGROUND: Calcium alginate gels are widely used to encapsulate active compounds. Some characteristic parameters of these gels are necessary to describe the release of active compounds through mechanistic mathematical models. In this work, transport and kinetics properties of calcium alginate gels were determined through simple experimental techniques. RESULTS: The weight-average molecular weight ( M ¯ w = 192 × 103 Da) and the fraction of residues of α-l-guluronic acid ( F G = 0.356) of sodium alginate were determined by capillary viscometry and 1 H-nuclear magnetic resonance at 25 °C, respectively. Considering the half egg-box model, both values were used to estimate the molecular weight of calcium alginate as M g = 2.02 × 105 Da. An effective diffusion coefficient of water ( D eff , w = 2.256 × 10-9 m2 s-1 ) in calcium alginate was determined using a diffusion cell at 37 °C. Finally, a kinetics constant of depolymerization ( k m = 9.72 × 10-9 m3 mol-1 s-1 ) of calcium alginate was obtained considering dissolution of calcium to a medium under intestinal conditions. CONCLUSION: The experimental techniques used are simple and easily reproducible. The obtained values may be useful in the design, production, and optimization of the alginate-based delivery systems that require specific release kinetics of the encapsulated active compounds. © 2023 Society of Chemical Industry.

The use of active compounds to shape the quality of active double-layer films based on furcellaran intended for packaging salad-dressing - Assessment of utilitarian and storage properties.

In order to obtain innovative, high-quality biodegradable packaging, double-layer films based on furcellaran and gelatin, enriched with plant extracts were created. The films were assessed considering their potential utility, applications and environmental impact. The mechanical properties over a period of nine months were studied and it was noted that the passing of time had a beneficial effect on these parameters. The antioxidant properties was also examined, with the highest results obtained using the DPPH and metal chelating activity methods for GE (76.64 % and 9.85 % respectively), while this film showed the lowest FRAP value (5.99 %) compared to the highest obtained for DTE (52.62 %). For the first time, the possibility of using the double-layer active FUR/GEL film as packaging for salad-dressing was evaluated, but no improvement in parameters was observed regardless of the extract used. The environmental impact analysis showed the ability to completely decomposed in vermicompost within several days.

Improving the quality of multi-layer films based on furcellaran by immobilising active ingredients and impact assessment of the use of a new packaging material.

To improve the quality of multi-layer film, four-layer films based on furcellaran and active ingredients: gelatin hydrolysate, curcumin, capsaicin, montmorillonite and AgNPs, were produced in an innovative manner. The films were characterised by SEM and AFM analysis. Along with an increase in the concentration of active ingredients, the structure of the film becomes less homogeneous, which may affect the functional properties. The objective of the study was to analyse changes in the functional properties of the newly-obtained films and to verify their potential as packaging materials for fish products. With the increase in active ingredient concentration, water properties also improved, but there were no noticeable significant effects on mechanical properties. For antioxidant properties, the obtained values were within 1.04-2.74 mM Trolox/mg (FRAP) and 7.67-40.49% (DPPH). The obtained multi-layer films were examined with regard to the shelf-life of salmon. For this purpose, salmon fillets were packed in films having good antioxidant and functional properties. The films were effective in microorganism growth inhibition responsible for fillet spoilage during storage. The microorganism number in the active film-stored samples was lower by 0.13 log CFU/g on day 12 versus the control. However, film application did not retard lipid oxidation in the salmon fillets. Nonetheless, the films show great potential as active packaging materials, extending the shelf-life of the packed foods.

In Vitro Bioaccessibility Assessment of Phenolic Compounds from Encapsulated Grape Pomace Extract by Ionic Gelation.

Grape pomace is a by-product of winemaking characterized by a rich chemical composition from which phenolics stand out. Phenolics are health-promoting agents, and their beneficial effects depend on their bioaccessibility, which is influenced by gastrointestinal digestion. The effect of encapsulating phenol-rich grape pomace extract (PRE) with sodium alginate (SA), a mixture of SA with gelatin (SA-GEL), and SA with chitosan (SA-CHIT) on the bioaccessibility index (BI) of phenolics during simulated digestion in vitro was studied. A total of 27 individual phenolic compounds (IPCs) were quantified by UHPLC. The addition of a second coating to SA improved the encapsulation efficiency (EE), and the highest EE was obtained for SA-CHIT microbeads (56.25%). Encapsulation affected the physicochemical properties (size, shape and texture, morphology, crystallinity) of the produced microbeads, which influenced the delivery of phenolics to the intestine and their BI. Thus, SA-GEL microbeads had the largest size parameters, as confirmed by scanning electron microscopy (SEM), and the highest BI for total phenolic compounds and IPCs (gallic acid, 3,4-dihydroxybenzoic acid and o-coumaric acid, epicatechin, and gallocatechin gallate) ranged from 96.20 to 1011.3%. The results suggest that encapsulated PRE has great potential to be used as a functional ingredient in products for oral administration.

Green polymer altered in-situ gel oral liquid sustainable release preparation of vildagliptin suitable for dysphagic diabetic patients: assessment in-vitro & in-vivo.

PURPOSE: This work aimed to fabricate alginate based in-situ gelling matrix of vildagliptin improved by calcium and carboxy methyl cellulose (CMC) for appropriate adjustment of the onset and duration of action. This easy-to-swallow thickened liquid preparation aimed to improve compliance for dysphagic or elderly diabetic patients. METHODS: Vildagliptin dispersions containing alginate were fabricated in the presence or absence of calcium chloride to assess the effect of calcium ion, then a matrix containing 1.5% w/v of sodium alginate with calcium was further examined after the addition of CMC with different concentrations ranging from 0.1% to 0.3%. The viscosity, gelling forming property, Differential scanning calorimetry, and in-vitro drug release were assessed before monitoring the hypoglycemic effect of the selected formulation. RESULTS: In-situ gel matrixes were fabricated at gastric pH with and without calcium ions. The best formula concerning viscosity and the gel-forming property was achieved with higher CMC concentrations, which in turn decreased the rate of vildagliptin release in stimulated gastric pH. In-vivo results confirmed the extended hypoglycemic effect of the vildagliptin in-situ gelling matrix compared to the vildagliptin aqueous solution. CONCLUSION: This study represents a green polymeric-based in-situ gel as a liquid oral retarded release preparation intended for reducing dose frequency, easier administration of vildagliptin, and improving compliance in geriatric and dysphagic diabetic patients.

Primary hepatocyte urea assessment in the sodium-alginate patterned hydrogel by electrochemical procedure containing umbilical cord conditioned media.

Limitations in liver transplantation and advances in cell therapy methods motivated us to study primary hepatocytes. The main challenge in using primary hepatocytes for liver regeneration is that they lose their functionalities. We aimed to develop a controlled-shape hydrogel and apply the conditioned-media of mesenchymal stromal cells (CM-MSCs) to improve in vitro hepatocyte functions. In this experimental study, following rat hepatocyte isolation by collagenase perfusion and collection of human umbilical cord CM-MSCs, a simple and precise system called electrodeposition was used to produce the patterned alginate hydrogel. To reduce the cytopathic effects, we used an indirect electrodeposition method. For characterizing this structure, mechanical properties, Fourier-transform infrared spectroscopy (FTIR), water uptake, in-vitro degradation, and hydrogel stability were studied. Urea synthesis as a basic function of hepatocytes was assessed in five different groups. Scanning electron microscope (SEM) was utilized to evaluate the primary hepatocyte morphology and their dispersion in the fabricated structure. We observed a significant increase in urea synthesis in the presence of CM-MSCs in patterned hydrogel alginate compared to 2D culture on day 3 (p<0.05). However, there was no significant difference in simple and patterned hydrogel on day 2. We found that the electrodeposition method is appropriate for the rapid fabricating of hydrogel structures with arbitrary patterns for 3D cell culture.

Assessment of temperature-sensitive properties of ionically crosslinked sodium alginate/hydroxypropyl cellulose blend microspheres: preparation, characterization, and in vitro release of paracetamol.

Today, polymer systems can be formed to respond to single stimuli or multiple stimuli by changing their properties. The use of these systems, which are designed to be sensitive to stimuli, is expanding in a wide range of applications. Herein, microspheres of sodium alginate (NaAlg) and hydroxypropyl cellulose (HPC) sensitive to dual stimuli for the controlled release of model drug paracetamol were produced by the ionotropic gelation method in the presence of Zn2+ ions. FTIR, DSC, TGA, SEM, and particle size measurements were used to describe the blend microspheres. Low critical solution temperatures (LCST) of polymer blends at different ratios were determined and the biggest change according to the LCST value of HPC was found to be approximately 1-2 °C lower than 41 °C in microspheres with a NaAlg/HPC ratio of 50/50. In vitro release experiments of paracetamol from microspheres were carried out in a gastrointestinal tract simulation environment at two different temperatures (37 °C and 47 °C). From the release profiles, paracetamol release varied depending on the NaAlg/HPC ratio, the paracetamol content in the microspheres, the exposure time to Zn2+ ions, and the pH of the medium. Among the microsphere formulations, the highest entrapment efficiency was 57.86%, obtained for B7 formulation microspheres with a NaAlg/HPC ratio of 70/30, a paracetamol loading percentage of 20%, and a crosslinking time of 5 min.RESEARCH HIGHLIGHTSMicrospheres of sodium alginate (NaAlg) and hydroxypropyl cellulose (HPC) sensitive to dual stimuli for the controlled release of model drug paracetamol were produced by the ionotropic gelation method in the presence of Zn2+ ions.LCST values of the microspheres with a NaAlg/HPC ratio of 50/50 were significantly lower by 1-2 °C than the LCST value of HPC, and the release results supported the temperature sensitivity of the microspheres.Among the microsphere formulations, the highest entrapment efficiency was 57.86% obtained for B7 formulation microspheres.These microspheres can be used as a temperature-sensitive drug delivery system in the biomedical field and also as an encapsulation system of cancer drugs for cancer treatment modalities such as hyperthermia.

3D Extrusion Printing of Biphasic Anthropomorphic Brain Phantoms Mimicking MR Relaxation Times Based on Alginate-Agarose-Carrageenan Blends.

The availability of adapted phantoms mimicking different body parts is fundamental to establishing the stability and reliability of magnetic resonance imaging (MRI) methods. The primary purpose of such phantoms is the mimicking of physiologically relevant, contrast-creating relaxation times T1 and T2. For the head, frequently examined by MRI, an anthropomorphic design of brain phantoms would imply the discrimination of gray matter and white matter (WM) within defined, spatially distributed compartments. Multichannel extrusion printing allows the layer-by-layer fabrication of multiple pastelike materials in a spatially defined manner with a predefined shape. In this study, the advantages of this method are used to fabricate biphasic brain phantoms mimicking MR relaxation times and anthropomorphic geometry. The printable ink was based on purely naturally derived polymers: alginate as a calcium-cross-linkable gelling agent, agarose, ι-carrageenan, and GdCl3 in different concentrations (0-280 µmol kg-1) as the paramagnetic component. The suggested inks (e.g., 3Alg-1Agar-6Car) fulfilled the requirements of viscoelastic behavior and printability of large constructs (>150 mL). The microstructure and distribution of GdCl3 were assessed by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX). In closely monitored steps of technological development and characterization, from monophasic and biphasic samples as printable inks and cross-linked gels, we describe the construction of large-scale phantom models whose relaxation times were characterized and checked for stability over time.

Curcumin encapsulated polylactic acid nanoparticles embedded in alginate/gelatin bioinks for in situ immunoregulation: Characterization and biological assessment.

Curcumin is a known naturally occurring anti-inflammatory agent derived from turmeric, and it is commonly used as a herbal food supplement. Here, in order to overcome the inherent hydrophobicity of curcumin (Cur), polylactic acid (PLA) nanoparticles (NPs) were synthesised using a solvent evaporation, and an oil-in-water emulsion method used to encapsulate curcumin. Polymeric NPs also offer the ability to control rate of drug release. The newly synthesised NPs were analysed using a scanning electron microscope (SEM), where results show the NPs range from 50 to 250 nm. NPs containing graded amounts of curcumin (0 %, 0.5 %, and 2 %) were added to cultures of NIH3T3 fibroblast cells for cytotoxicity evaluation using the Alamar Blue assay. Then, the curcumin NPs were incorporated into an alginate/gelatin solution, prior to crosslinking using a calcium chloride solution (200 nM). These hydrogels were then characterised with respect to their chemical, mechanical and rheological properties. Following hydrogel optimization, hydrogels loaded with NP containing 2 % curcumin were selected as a candidate as a bioink for three-dimensional (3D) printing. The biological assessment for these bioinks/hydrogels were conducted using THP-1 cells, a human monocytic cell line. Cell viability and immunomodulation were evaluated using lactate dehydrogenase (LHD) and a tumour necrosis factor alpha (TNF-α) enzyme-linked immunosorbent (ELISA) assay, respectively. Results show that the hydrogels were cytocompatible and supressed the production of TNF-α. These bioactive hydrogels are printable, supress immune cell activation and inflammation showing immense potential for the fabrication of tissue engineering constructs.

The assessment of microencapsulated Lactobacillus plantarum survivability in rose petal jam and the changes in physicochemical, textural and sensorial characteristics of the product during storage.

The present study aimed to develop a probiotic rose petal jam containing microencapsulated L. plantarum. The attributes of L. plantarum microcapsules and bacteria viability in simulated gastrointestinal conditions and jam were assessed. In addition, L. plantarum effects on physicochemical, textural and sensorial properties of jam were studied. The microencapsulation yield, diameter, and zeta potential value of the microcapsules ranged from 90.23 to 92.75%, 14.80-35.02 µm, and - 16.83 to - 14.71 mV, respectively. The microencapsulation process significantly increases the survival of L. plantarum in simulated gastrointestinal tract and jam. In jam samples containing L. plantarum microencapsulated with 2% sodium alginate and 3.5% or 5% Arabic gum and stored for 90 days, the bacterial count was higher than the acceptable level (106 CFU/g). While there was no significant difference (P > 0.05) between physicochemical characteristics of non-probiotic and probiotic jams, taste and overall acceptance scores of microencapsulated probiotic jams were higher. The microencapsulation of L. plantarum in sodium alginate (2%) and Arabic gum (5%) and its inoculation into rose petal jam could yield a new probiotic product with increased health benefits.

One-step preparation of photoclick method for embolic microsphere synthesis and assessment for transcatheter arterial embolization.

Vascular embolization is a well-known therapeutic treatment against hepatocellular carcinoma. However, existing embolic agents require complex synthesis, toxic organic solvents and sometimes produce only low yields. In this study, a novel photopolymerization technique, which addresses these issues, was used to prepare embolic microspheres successfully from the sucrose multi-allyl ether monomer in one step. Compared to the preparation of such microspheres always involved in multiple steps or complicated conditions, we obtained the microspheres used photoclick method in a soft template with simple, economic and feasible procedure. This work focuses on the synthesis of new materials by conducting a photopolymerzation in the presence of the sucrose monomer and the photoinitiator. Then, the embolic microspheres obtained were characterized by morphology assay, degradation, and swelling test. Cell experiments showed that the microspheres had good biocompatibility. Rabbit embolizations showed that the microspheres had long-term embolic effects. It is manifested that one-step preparation of photoclick method hold great potential and competitiveness of being used in preparation embolic microspheres in clinic.

Entrapment of nano-ZnO into alginate/polyvinyl alcohol beads with different crosslinking ions for fertilizer applications.

Zinc oxide nanoparticles (nano-ZnO) are attractive as fertilizer materials but high concentrations may negatively affect the environment. To reduce their dispersion in the environment we entrapped nano-ZnO in biodegradable polymer beads consisting of alginate and polyvinyl alcohol (PVA). The alginate/PVA/ZnO beads were prepared via ionotropic gelation using two different crosslinking ions (Ca2+ and Zn2+), and the effect of alginate crosslinking ion and PVA content on bead structure, water absorption, water retention and zinc release was investigated. The pure CaAlg and ZnAlg beads demonstrated a poor water absorption and retention, which were strongly enhanced by the incorporation of PVA into the beads. The continuous Zn release was measured in a sand column, and it was found that the Zn-crosslinked beads rapidly released high concentrations of Zn followed by a more gradual Zn release, whereas Ca alginates showed only a gradual Zn release. The Zn dissolution kinetics could be tuned by the crosslinking ion composition. The prepared nano-ZnO-containing alginate/PVA beads may be attractive for Zn fertilizer applications under water-limited conditions.

Rice vinasse treatment by immobilized Synechococcus pevalekii and its effect on Dunaliella salina cultivation.

The development of new strategies in microalgal studies represents an outstanding opportunity to mitigate environmental problems coupled with biomass production at a reduced cost. Here we present a combined bioprocess for the treatment of rice vinasse using immobilized cyanobacteria Synechococcus pevalekii in alginate beads followed by the use of the treated vinasse as a culture medium for Dunaliella salina biomass production. Cyanobacterial-alginate beads showed a chlorophyll a production of 0.68 × 10-3 mg bead-1 and a total carotenoid production of 0.64 × 10-3 mg bead-1. The first step showed a decrease in nitrate (91%), total solids (29%), and ions. Addition of treated vinasse into D. salina cultivation resulted in a significant increase in cell replication of about 175% (optimized cultivation). The use of natural seawater drastically reduced the medium cost to US$4.75 per m3 and the addition of treated vinasse has the potential to reduce it even more (up to 69%). This study not only provides an insight on the use of cyanobacteria for rice vinasse treatment but also demonstrates a promising lower-cost medium for marine microalgal biomass production with biotechnological purposes.

Physicochemical features assessment of acemannan-based ternary blended films for biomedical purposes.

The exploitation of natural origin macromolecules, as complex physical mixtures or drugs, increases in biomedical or tissue engineering (TE) solutions. Aloe Vera is a highly explored medicinal plant, from which the main polysaccharide is acemannan (ACE). The ACE combination with chitosan and alginate results in interactions that lead to mixed junction zones formation, predicting membrane functionality improvement. This work proposes the development and characterization of ACE-based blended films as a promising strategy to design a nature-derived bioactive platform. The results confirmed that stable complex polyelectrolyte structures were formed through different intermolecular interactions. The films present good dimensional stability, flexibility, an adequate swelling ability with mostly radial water uptake, and a sustainable ACE release to the medium. Positive biological performance of the ACE-based blended films with L929 cells also suggested that they can be applied in TE solutions, with the potential to act as bioactive topical platforms.

Wearable Bracelet Monitoring the Solar Ultraviolet Radiation for Skin Health Based on Hybrid IPN Hydrogels.

The risk of extensive exposure of the human epidermis to solar ultraviolet radiation is significantly increased nowadays. It not only induces skin aging and solar erythema but also increases the possibility of skin cancer. Therefore, a simply prepared, highly sensitive, and optically readable device for monitoring the solar ultraviolet radiation is highly desired for the skin health management. Because of the photoinitiated polymerization triggered by graphene-carbon nitride (g-C3N4) under ultraviolet radiation, g-C3N4 is homogeneously distributed in the hybrid hydrogels containing N-isopropylacrymide (NIPAM), poly(ethylene glycol) methyl ether methacrylate (OEGMA300), and sodium alginate (SA). By further immersing the hybrid hydrogels into calcium chloride solution, hybrid alginate-Ca2+/P(NIPAM-co-OEGMA300)/g-C3N4 interpenetrating polymeric network (IPN) hydrogels are obtained. Due to the homogeneous distribution of g-C3N4 and the existence of thermoresponsive polymers, the hybrid IPN hydrogels present good adsorption capability and high degradation efficiency for methylene blue (MB) especially at high temperature under ultraviolet radiation. Based on this unique property, the bracelet monitoring skin health is prepared by simply immersing the hybrid IPN hydrogels into the MB solution and then wrapping it with PET foil. Because the immersion time for the top, middle, and bottom parts of the hybrid IPN hydrogels is gradually increased, their colors vary from light to dark blue. A longer time is required for the discoloration of the darker part under solar ultraviolet radiation. Thus, the bracelet can be used to conveniently monitor the dose of solar ultraviolet radiation by simply checking the discoloration in the bracelet under sunshine. Due to the facile preparation and low cost of the bracelet, it is a promising candidate for wearable devices for skin health management.

Developing 3D-Printable Cathode Electrode for Monolithically Printed Microbial Fuel Cells (MFCs).

Microbial Fuel Cells (MFCs) employ microbial electroactive species to convert chemical energy stored in organic matter, into electricity. The properties of MFCs have made the technology attractive for bioenergy production. However, a challenge to the mass production of MFCs is the time-consuming assembly process, which could perhaps be overcome using additive manufacturing (AM) processes. AM or 3D-printing has played an increasingly important role in advancing MFC technology, by substituting essential structural components with 3D-printed parts. This was precisely the line of work in the EVOBLISS project, which investigated materials that can be extruded from the EVOBOT platform for a monolithically printed MFC. The development of such inexpensive, eco-friendly, printable electrode material is described below. The electrode in examination (PTFE_FREE_AC), is a cathode made of alginate and activated carbon, and was tested against an off-the-shelf sintered carbon (AC_BLOCK) and a widely used activated carbon electrode (PTFE_AC). The results showed that the MFCs using PTFE_FREE_AC cathodes performed better compared to the PTFE_AC or AC_BLOCK, producing maximum power levels of 286 µW, 98 µW and 85 µW, respectively. In conclusion, this experiment demonstrated the development of an air-dried, extrudable (3D-printed) electrode material successfully incorporated in an MFC system and acting as a cathode electrode.

Fabrication of three-dimensional calcium alginate hydrogels using sacrificial templates of sugar.

Hydrogels are receiving increasing attention in bioapplications. Among hydrogels, calcium alginate (Ca-alginate) hydrogels are widely used for their biocompatibility, low toxicity, low cost, and rapid fabrication by simple mixing of Ca2+ and sodium alginate (Na-alginate). For bioapplications using hydrogels, it is necessary to construct designed hydrogel structures. Although several methods have been proposed for fabricating designed hydrogels, a simple and low-cost method is desirable. Therefore, we developed a new method using sacrificial templates of sugar structures to fabricate three-dimensional (3D) designed Ca-alginate hydrogels. In this method, Na-alginate solution is mixed with molten sugar, and the resulting highly viscous material used to mold 3D sugar structures as sacrificial templates. Since sugar constructs are easily handled compared to hydrogels, sugar templates are useful for preparing 3D constructs. Finally, the sugar and Na-alginate structure is immersed in a CaCl2 solution to simultaneously dissolve the template and form the Ca-alginate hydrogel. The resulting hydrogel takes the shape of the sugar template. By stacking and fusing various sugar structures, such as fibers and blocks, 3D designed Ca-alginate hydrogels can be successfully fabricated. This simple and low-cost method shows excellent potential for application to a variety of bioapplications.