Search Results (207)

This study investigates water-based gel and gel-like cleaning treatments on Superficie 553, an oil painting on canvas by Giuseppe Capogrossi, using portable NMR to assess their impact. The objective was to evaluate the effects of four cleaning systems composed of a buffer solution released in free form and combined with xanthan gum, a cross-linked silicone polymer gel, and an agar gel matrix. Two distinct NMR experiments were conducted. The first involved the acquisition of ¹H depth profiles to detect the distribution of the cleaning solution within the painted layer and the thickness variations resulting from cleaning procedures. The second employed the acquisition of relaxation times, facilitating the investigation of molecular mobility within the organic components of the paint layer. NMR results indicated that the agar gel system caused negligible structural changes, whereas the silicone gel induced rigidification, and the other systems permanently increased molecular mobility. These measurements provided insights into alterations in the dynamic behavior of the polymerized oil. A key strength of this investigation lies in the direct application of diagnostic methods on Superficie 553, made possible by the non-invasive nature and portability of the NMR-MOUSE system. Additionally, portable FTIR was used to detect residues and obtain chemical information, confirming that the silicone gel left detectable residues and identifying the agar gel as the most conservative cleaning method. This enabled in situ analysis of the original artwork without sampling or relocation—a crucial advantage given the difficulty of replicating the complex physicochemical conditions of historical paint surfaces under laboratory constraints. Such real-time, on-site monitoring ensured an authentic evaluation of the treatment effects, preserving the integrity of the artwork throughout the conservation process. Full article

Orange peel waste has potential to be valorized from agro-industrial and food sectors to formulate products for personal hygiene and public health. This study presents the formulation of alcohol-based antibacterial gels incorporating essential oils extracted from Citrus sinensis orange peel waste and its sensory evaluation among 770 participants in a holistic approach. The orange essential oil, obtained via hydrodistillation, demonstrated a high limonene content of 96.5% by GC-MS. Antibacterial activity assessed by agar diffusion assays showed orange essential oil efficacy against Escherichia coli and Staphylococcus aureus, with inhibition zones of 25.9 mm and 23.62 mm, respectively. Two gel prototypes, GSA and GSB, were developed and sensorily evaluated. GSA was preferred for its superior appearance, spreadability, absorption, and smell, with 99% acceptability. Appearance and spread sensory parameters were the differentiators between both formulations according to user preferences. Thus, 93% of respondents are willing to use either GSA or GSB as a daily hygiene product over commercial ones. Although the gels exhibited reduced antibacterial activity relative to essential oil, with inhibition zones measuring 8.3 mm for E. coli and 9.0 mm for S. aureus, they retained satisfactory user acceptability. These findings support the use of citrus biowaste-derived essential oils in sustainable personal hygiene products. Full article

The environmental sustainability of cleaning materials used in heritage conservation remains poorly quantified despite growing attention to the replacement of hazardous petroleum-based solvents with bio-based alternatives. This study applies a comprehensive Life Cycle Assessment (LCIA) to compare conventional solvents with innovative bio-based formulations, including Fatty Acid Methyl Esters (FAMEs), Deep Eutectic Solvents (DES), and aqueous or organogel systems used for cleaning painted surfaces. Following ISO 14040/14044 standards and using the Ecoinvent v3.8 database with the EF 3.1 impact method, three functional units were adopted to reflect material and system-level scales. Results demonstrate that water-rich systems, such as agar gels and emulsified organogels, yield significantly lower climate and toxicity impacts (up to 85–90% reduction) compared with petroleum-based benchmarks, while FAME and DES exhibit outcomes highly dependent on allocation rules and baseline datasets. When including application materials, cotton wipes dominate total environmental burdens, emphasizing that system design outweighs solvent substitution in improving sustainability. The study provides reproducible data and methodological insights for integrating LCIA into conservation decision-making, contributing to the transition toward evidence-based and environmentally responsible heritage practices. Full article

The agar is an important polysaccharide widely used in the food industry, pharmaceuticals, cosmetics, microbiology, and molecular biology applications. The global demand for agar polysaccharide is steadily rising, but its production is limited due to shortage of good raw material. This research investigates the potential of Gelidium micropterum as an alternative and sustainable source of high-quality agar. Agar was extracted using different concentrations of NaOH (4, 6, 8, and 10% w/v) and without NaOH treatment. The resulting agar yields ranged from 16.97% to 26.03%, with corresponding gel strengths between 855 ± 51 and 2078 ± 55 g/cm². Notably, 8% and 10% NaOH pre-treatments yielded agar with superior gel strength and thermal properties, surpassing those reported for other Gelidiales species under similar conditions. Structural characterisation was performed using FT-IR, ¹³C-NMR, and ¹H-NMR spectroscopy, confirming similarities with standard agar. The extracted agar’s molecular weights were in the range of 5704–7276 kDa. Sulphate content varied from 0.175 ± 0.082% to 6.197 ± 0.446% across treatments. The agar also supported microbial growth at lower concentrations than commercial agar, indicating promising application potential. These findings highlight G. micropterum as a promising, sustainable option for expanding agar resources. Full article

The Indonesian coastline holds significant potential for aquaculture but is increasingly vulnerable to climate change impacts such as land subsidence, salinization, and floodings. Ensuring stable income for local communities is essential, especially during extreme events like King Tides, which cause extensive floodings. This study assessed the productivity and economic returns of an agaroid seaweed monoculture compared to co-cultivation with Giant tiger prawn, Milkfish, and Barramundi during a King Tide. The experiment was conducted in conventional ponds with seaweed monoculture or combined with one of the three other commodities. The experiment ran from May until October in 2022 and was performed in triplicate. Floodings equalized water parameters. The results demonstrated that all systems provided stable income, with co-cultivation increasing profitability. Average revenues per hectare were USD 777 (seaweed monoculture), USD 832 (with shrimp), USD 1622 (with Milkfish), and USD 2014 (with Barramundi). Agar content was significantly higher in the seaweed monoculture, and gel strength was found to be significantly higher in the seaweeds co-cultivated with shrimp and Milkfish. Total agar production did not differ between the treatments. These findings suggest that integrated aquaculture systems can enhance income resilience while supporting food security in climate-impacted coastal zones. The approach offers a promising strategy for combining livelihood stability with adaptive coastal management and reduced environmental impact but needs to be tailored to local conditions. Full article

The global increase in the older population presents a nutritional challenge; therefore, the development of food products for this group must take into account the physiological changes associated with aging. This work aimed to evaluate the effects of droplet size, conventional emulsion (CE) and nanoemulsion (NE), and different hydrocolloids, soy protein (SPI), whey protein (WPI), agar (AG), and κ-carrageenan (CAR), on the physical properties, lipid digestibility, and bioaccessibility of emulsion-based gels enriched with vitamin D. The main findings indicated that all gels exhibited non-Newtonian behavior and suitable viscosity and texture for the swallowing needs of older people. The highest release of free fatty acids (~30%) was observed in the NE + WPI sample, independent of droplet size. Instead, SPI gels showed the highest vitamin D bioaccessibility, likely due to their less-structured gel network. Thus, gels containing WPI + AG provide a favorable balance between an easy-to-swallow texture and efficient nutrient release, making them suitable for producing food based on emulsion-filled gels with good physical and nutritional properties. Hence, these results highlight the potential of tailored hydrocolloid combinations to develop nutrient-fortified and texture-appropriate gels that address the nutritional needs of the older population. Full article

Cellulose acetate (CA) is a semi-synthetic polymer widely present in modern and contemporary collections, yet its conservation poses major challenges due to its chemical and physical instability. Hydrolytic degradation, acetic acid release, plasticizer loss, and embrittlement compromise both structure and surface, making cleaning particularly difficult. Conventional cleaning methods may cause abrasion, extract additives, or alter gloss. Although hydrogels have shown promise for CA cleaning, the literature remains extremely limited. This study reports a preliminary investigation of gel-based cleaning on Le Rituel (1968), a heavily soiled cellulose acetate (CA) artwork by José Escada. The object’s condition was assessed through visual inspection, pH measurements, volatile acidity testing, and infrared spectroscopy. Cleaning tests were conducted on a CA replica (2006) with superficial soiling and on selected artwork areas. Two gel formulations were evaluated: the biopolymer agar-agar rigid gel and the synthetic viscoelastic poly(vinyl alcohol)-borax (PVAl-Borax) gel. Agar-agar was effective as a first step, reducing superficial soiling and humidifying adherent residues for subsequent removal, while PVAl-Borax was advantageous in the second step, as its viscoelastic properties enabled controlled mechanical action and facilitated the removal of more adherent residues. This case study demonstrates the potential of combined gel systems as versatile tools for CA conservation. Full article

The progressive aging of the population requires reliable, non-invasive, and real-time tools to monitor hydration, prevent dehydration-related complications, and promote active aging in elderly patients. Wearable sensors based on interdigitated electrodes (IDEs) and on Electrochemical Impedance Spectroscopy (EIS) represent a promising tool thanks to their miniaturization, sensitivity to dielectric variations with humidity, and compatibility with flexible substrates. This study reports the design, fabrication, and metrological characterization of inkjet-printed IDEs for skin hydration monitoring, as a building block of a multisensor wearable device. IDEs were fabricated on polyimide substrates using silver nanoparticle-based ink. Their characterization involved the following: (i) morphological evaluation by scanning electron microscopy; (ii) EIS measurements in KCl solutions, leading to developing a regression model to correlate impedance with salt concentration; (iii) in vitro EIS validation on agar gel samples, which demonstrated a robust linear relationship between the impedance phase shift at 199.5 $\mathrm{Hz}$ and water loss, with consistent sensitivity values across sensors. The results confirm the feasibility of IDEs for hydration monitoring, identifying optimal frequency ranges and validating regression models. These findings represent a critical step toward the development of multisensor wearable devices for elderly monitoring, enabling decentralized and continuous health monitoring to improve healthcare sustainability and telemedicine. Full article

Microbial colonization is a major factor contributing to peri-implantitis, and creating durable glassy surfaces with antimicrobial agents such as silver and copper may reduce microbial accumulation on dental abutments. This study aimed to develop antimicrobial thin-film glassy surfaces on Ti6Al4V alloy and to evaluate their surface and mechanical properties, antimicrobial effectiveness, and biocompatibility before and after thermal aging. A sol–gel-derived glassy matrix (G) was synthesized, and two antimicrobial coatings were prepared by incorporating ionic Ag (GAg) or a combination of Ag/Cu (GAgCu). Ti6Al4V specimens; these were either left uncoated or dip-coated with G, GAg, or GAgCu and cured at 450 °C. Half of the specimens underwent thermal aging between 5 °C and 55 °C for 3000 cycles. Surface roughness, contact angle, hardness, adhesion strength, scratch resistance, cytotoxicity (Agar diffusion and MTT assay on L929 fibroblasts), and microbial adhesion were evaluated using Streptococcus sanguinis, Porphyromonas gingivalis, and Candida albicans as representative oral microorganisms. Both coatings exhibited low surface roughness, hydrophilic surfaces, improved hardness, and significantly reduced microbial adhesion for all tested species. GAg showed superior mechanical properties, whereas GAgCu demonstrated a relatively stronger antimicrobial effect. Cytotoxicity tests indicated that all coatings were biocompatible at levels suitable for oral use. Overall, these coatings demonstrated strong adhesion, durability, and antimicrobial activity, suggesting their suitability for dental abutments made of Ti6Al4V. Full article

Diabetic foot ulcers (DFUs) and other chronic wounds are major global health challenges, often complicated by infections and delayed healing due to excessive collagen accumulation. Microbial collagenases offer an enzymatic alternative to surgical debridement by selectively degrading collagen and potentially limiting microbial colonization. In this study, an isolated and characterized thermostable collagenase from Streptomyces scabies from rhizospheric soil in Al-Lith thermal springs, Saudi Arabia, is investigated. Identification was confirmed via 16S rRNA sequencing, and enzyme production was optimized on gelatin agar. Partial purification was achieved through ammonium sulfate precipitation and dialysis, and molecular weight (~25 kDa) was determined by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Activity was assessed under varying temperatures, pH, substrates, and metal ions, while antibacterial potential was tested against Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The collagenase exhibited optimal activity at 80 °C and pH 9, stability under thermophilic and alkaline conditions, activation by Fe²⁺, and notable antibacterial effects at higher concentrations. These results demonstrate that S. scabies collagenase exhibits selective antibacterial activity in vitro, suggesting its potential as an enzymatic tool for further evaluation in diabetic foot debridement and infection control. Full article

The shift towards renewable resources has positioned agar, a natural seaweed polysaccharide, as a pivotal and sustainable material for developing next-generation energy storage technologies. This review highlights the transformative role of agar-based composites as a game-changing and eco-friendly platform for supercapacitors, batteries, and fuel cells. Moving beyond the traditional synthetic polymers, agar introduces a novel paradigm by leveraging its natural gelation, superior film-forming ability, and inherent ionic conductivity to create advanced electrolytes, binders, and matrices. The novelty of this field lies in the strategic fabrication of synergistic composites with polymers, metal oxides, and carbon materials, engineered through innovative techniques like electrospinning, solvent casting, crosslinking, 3D printing, and freeze-drying. We critically examine how these innovative composites are breaking new ground in enhancing device efficacy, flexibility, and thermal stability. Ultimately, this analysis not only consolidates the current landscape but also charts future pathways, positioning agar-based materials as a pivotal and sustainable solution for powering the future. Full article

New compostable materials have been developed to replace single-use soft materials such as polyurethane foams (PUR). To this end, eco-friendly systems have been formulated on the basis of agar gels prepared in mixed solvent (glycerol/water) to meet specifications, i.e., stiffness of several hundred kPa, reasonable extensibility, and good stability when exposed to open air. While the addition of glycerol slows down gelation kinetics, mechanical properties are improved up to a glycerol content of 80 wt%, with enhanced extensibility of the gels while maintaining high Young’s moduli. Swelling analyses of mixed gels, in water or pure glycerol, demonstrate the preservation of an energetic network, with no change in volume, in pure water and the transition towards an entropic network in glycerol related to the partial dissociation of helix bundles. Dimensional and mechanical analysis of gels aged in an open atmosphere at room temperature shows that the hygroscopic character of glycerol enables sufficient water retention to maintain the physical network, with antagonistic effects linked to relative increases in glycerol, which tends to weaken the network, and agar, which on the contrary strengthens it. Complementary analyses carried out on aged agar gels formulated with an initial glycerol/water mass composition of 60/40, the most suitable for the targeted development, enabled the comparison of the properties of agar gels favorably with those of PURs and verified their stability during long-term storage, as well as their non-toxicity and compostability. Full article

Archeological ceramics represent values that necessitate preservation from various factors of deterioration. Cleaning processes are beneficial in the preservation of these ceramics. An abundance of cleaning technique and process information exists within the literature. This study examines the current state of both traditional and advanced cleaning techniques employed for archeological ceramics. The review discusses a wide range of commonly used cleaning techniques, including mechanical, dry and wet processes, as well as chemical approaches. Additionally, more recent laser, plasma, and biocleaning methods are discussed. The effectiveness of these techniques is examined, as well as potential damage or surface modifications to the ceramics. The selection of a cleaning method for ceramics depends on the specific characteristics of the ceramic (i.e., porosity, glaze, slip red-slipped, etc.), its state of conservation, and the nature and thickness of the fouling or encrustations. Careful selection and testing of chemical solutions are crucial to prevent damage. While chelating agents like EDTA effectively dissolve crusts and salts, uncontrolled application can weaken ceramic structures. Laponite, natural clay minerals, resins and organic gels (xanthan gum, agar, cellulose powder) are effective in removing contaminants from the surfaces of without causing damage. Environmentally friendly methods such as biocleaning, Pulsed Laser Cleaning, and plasma are effective but underutilized, requiring further investigation. This review emphasizes the growing potential of sustainable and non-invasive methods to complement or replace traditional approaches. Its main contribution lies in providing a critical synthesis that bridges conventional and innovative techniques, outlining research gaps for more effective and eco-responsible conservation of archeological ceramics. Full article

Edible hydrogels are the central material class in 3D food printing because they reconcile two competing needs: (i) low resistance to flow under nozzle shear and (ii) fast recovery of elastic structure after deposition to preserve geometry. This review consolidates the recent years of progress on hydrogel formulations—gelatin, alginate, pectin, carrageenan, agar, starch-based gels, gellan, and cellulose derivatives, xanthan/konjac blends, protein–polysaccharide composites, and emulsion gels alongside a critical analysis of printing technologies relevant to food: extrusion, inkjet, binder jetting, and laser-based approaches. For each material, this review connects gelation triggers and compositional variables to rheology signatures that govern printability and then maps these to process windows and post-processing routes. This review consolidates a decision-oriented workflow for edible-hydrogel printability that links formulation variables, process parameters, and geometric fidelity through standardized test constructs (single line, bridge, thin wall) and rheology-anchored gates (e.g., yield stress and recovery). Building on these elements, a “printability map/window” is formalized to position inks within actionable operating regions, enabling recipe screening and process transfer. Compared with prior reviews, the emphasis is on decisions: what to measure, how to interpret it, and how to adjust inks and post-set enablers to meet target fidelity and texture. Reporting minima and a stability checklist are identified to close the loop from design to shelf. Full article

Environmental pollution by hard-to-degrade polymers is on a steep rise and impacting the entire ecosystem. Microbial keratinases are pivotal in the breakdown of protein polymers that are otherwise resistant to most proteases. In this study, we isolated and identified bacteria from Sua pan soil through morphological, biochemical, and 16SrRNA sequencing approaches and further assessed these isolates for their keratinase production potential. Among the screened isolates, four bacteria, Bacillus cereus Bac 2, Bacillus sp. Bac 1, Pseudomonas aeruginosa Bac 3, and Achromobacter insuavis Bac 4, exhibited the highest degradation activity. B. cereus Bac 2 produced the widest clearance zone, whereas A. insuavis Bac 4 produced the narrowest clearance zone on feather meal agar. Protein bands observed in SDS-PAGE gels for the selected isolates further supported the presence of keratinolytic enzymes. We also investigated the effect of temperature and pH on keratinase activity and determined that all the keratinases were alkaline proteases, with B. cereus Bac 2, P. aeruginosa Bac 3, and Bacillus sp. Bac 1 showing maximum activity at a pH of 8.5, while A. insuavis Bac 4 had maximal activity at a pH of 8.0. Overall, our results indicated that B. cereus Bac 2 keratinase had significantly higher activity across all temperature and pH ranges investigated, compared to all the other isolates (p ≤ 0.0001). These findings highlight the potential application of bacterial isolates from alkalophilic environments, in the eco-friendly degradation of feather waste, as valuable by-products such as organic fertilizers, peptides, and amino acids. Full article