Search Results (300)

Background: This study aimed to evaluate the impact of different chemical treatments on titanium implant surfaces and their biological compatibility. Methods: Titanium dental implants were immersed in Ringer’s solution, hydrogen peroxide (3%), citric acid (40%), EDTA (40%), or a citric–phosphoric acid mixture. Electrochemical behavior was analyzed using open-circuit potential monitoring and electrochemical impedance spectroscopy over 168 h. Cytocompatibility was assessed by culturing human gingival mesenchymal stem cells (MSCs) directly on treated implants and in conditioned media, followed by viability evaluation through CCK-8 assays. Results: Citric acid and Ringer’s solution preserved passive film stability and supported high MSC viability (>75%) with minimal cytotoxic effects. Hydrogen peroxide and the citric–phosphoric acid mixture caused pronounced surface corrosion, decreased impedance stability, and significantly reduced cell viability (57–65%). EDTA-treated surfaces showed intermediate results, with moderate viability but impaired cell adhesion. Conclusion: The findings highlight the dual influence of chemical decontamination on implant stability and biological response. Citric acid and Ringer’s solution appear to be safer protocols for surface decontamination, whereas hydrogen peroxide and mixed acid treatments should be applied with caution due to their detrimental electrochemical and cytotoxic effects. Full article

The importance of purple corn (Zea mays L.) varieties has increased due to their high anthocyanin contents both in the kernels and the degrained cob. The aim of this work was to separate anthocyanins from degrained purple-corn cobs to assess their pigmentation potential in food matrices. Two populations of purple corn were used, namely, Negro de Ixtenco (NIX) and Negro de Ixtenco x Negro de Perú (PIX), collected in Juchitepec, Mexico. Flours of degrained cob were obtained with average moisture, crude protein, ash, lipid, crude fiber, and carbohydrate contents of 7.06, 3.70, 4.48, 0.76, 37.73, and 46.27%, respectively. Aqueous biphasic systems composed of a mixture of 7.88% trisodium citrate, 2.63% citric acid, and 50.88% ethanol were applied at an atmospheric pressure of 77,993.0 Pa and 25 °C, aided by ultrasound and orbital agitation. Extracts with anthocyanin concentrations of 33.01 and 39.55 mg per gram of degrained corn cob were obtained from NIX and PIX, respectively. Pigmentation kinetics were assessed in yogurt and corn dough, which had a logarithmic tendency towards hue angles of 2.25 and 333.05°, respectively. A 60% pigmentation relative to the limit was suggested, which required 0.45 and 11.65% of the extract in yogurt and corn dough, respectively. Pigmentation stability was verified in refrigerated yogurt and in cooked corn dough. Full article

This study presents the formulation of two natural antioxidant creams based on an oil-in-water emulsion system, incorporating either hydroxycitrate (HCA) from Garcinia cambogia (Gaertn.) or red wine powder (RWP) derived from Aglianico del Vulture red wine (Vitis vinifera L.). HCA, a derivative of citric acid, and RWP, rich in polyphenolic compounds, were chosen for their bioactive properties. The creams underwent a series of in vitro tests to assess their stability, cytocompatibility, and antioxidant properties. Cellular assays using HaCaT keratinocytes showed that both formulations were effective in reducing blue light-induced oxidative damage. Full article

With the rapid advancement of energy storage technologies, there is a growing demand for affordable, efficient, and environmentally benign battery systems. Sodium-ion batteries (SIBs) present a promising alternative to lithium-ion systems due to sodium’s high abundance and similar electrochemical properties. Particular attention is given to developing NASICON -sodium (Na) super ionic conductor, type cathode materials, especially Na3V2(PO4)3, which exhibits high thermal and structural stability. This study focuses on the sol–gel synthesis of Na₃V₂(PO₄)₃ using citric acid and ethylene glycol, as well as investigating the effect of annealing temperature (400–1000 °C) on its structural and electrochemical properties. Phase composition, morphology, textural characteristics, and electrochemical performance were systematically analyzed. Above 700 °C, a highly crystalline NASICON phase free of secondary impurities was formed, as confirmed by X-ray diffraction (XRD). Microstructural evolution revealed a transition from a loose amorphous structure to a dense granular morphology, accompanied by changes in specific surface area and porosity. The highest surface area (67.40 m²/g) was achieved at 700 °C, while increasing the temperature to 1000 °C caused pore collapse due to sintering. X-ray photoelectron spectroscopy (XPS) confirmed the predominant presence of V³⁺ ions and the formation of V⁴⁺ at the highest temperature. The optimal balance of high crystallinity, uniform elemental distribution, and stable texture was achieved at 900 °C. Electrochemical testing in a Na/NVP half-cell configuration delivered an initial capacity of 70 mAh/g, which decayed to 55 mAh/g by the 100th cycle, attributed to solid-electrolyte interphase (SEI) formation and irreversible Na⁺ trapping. These results demonstrate that the proposed approach yields high-quality Na₃V₂(PO₄)₃ cathode materials with promising potential for sodium-ion battery applications. Full article

Hydrogels comprise three-dimensional networks of hydrophilic polymers and have attracted considerable interest in various sectors, including the biomedical, pharmaceutical, agricultural, and food industries. These materials offer significant benefits for food packaging applications, such as high mechanical strength and excellent water absorption capacity, thereby contributing to the extension of product shelf life. Therefore, the aim of this study is to compare the performance of citric acid and glutaraldehyde as crosslinking agents in gelatine-based hydrogels reinforced with cellulose nanocrystals (CNC), contributing to the development of safe and environmentally responsible materials. The hydrogels were prepared using the casting method and characterised in terms of their physical, mechanical, and structural properties. The results indicated that hydrogels crosslinked with glutaraldehyde exhibited higher opacity, lower transparency, and greater mechanical strength, whereas those crosslinked with citric acid demonstrated improved clarity, reduced water permeability, and enhanced swelling capacity. The incorporation of CNC further improved mechanical strength, reduced weight loss, and altered both surface homogeneity and optical properties. Microstructural results obtained by SEM were consistent with the mechanical properties evaluated (TS, %E, and EM). The Gel-ca hydrogel displayed the highest elongation value (98%), reflecting better cohesion within the polymeric matrix. In contrast, films incorporating CNC exhibited greater roughness and cracking, which correlated with increased rigidity and mechanical strength, as evidenced by the high Young’s modulus (420 MPa in Gel-ga-CNC2). These findings suggest that the heterogeneity and porosity induced by CNC limit the mobility of polymer chains, resulting in less flexible and more rigid structures. Additionally, the DSC analysis revealed that gelatine hydrogels did not exhibit a well-defined Tg, due to the predominance of crystalline domains. Systems crosslinked with citric acid showed greater thermal stability (higher Tm and ΔH_m values), while those crosslinked with glutaraldehyde, although mechanically stronger, exhibited lower thermal stability. These results confirm the decisive effect of the crosslinking agent and CNC incorporation on the structural and thermal behaviour of hydrogels. In this context, the application of hydrogels in packaged products represents an eco-friendly alternative that enhances product presentation. This research supports the reduction in plastic consumption whilst promoting the principles of a circular economy and facilitating the development of materials with lower environmental impact. Full article

Waste materials have emerged as attractive low-cost feedstocks for adsorbent development in environmental remediation and materials engineering. Organic wastes are particularly rich in cellulose, hemicellulose, lignin, and pectin, which provide reactive oxygenated groups such as hydroxyls and carboxyls. While inorganic wastes offer stability, lower water retention makes them promising candidates. This study explores the functionalization of waste-derived organic and inorganic matrices using two amine-based agents: 3-aminopropyltrimethoxysilane (APTMS) and polyethylenimine (PEI). The materials were categorized as organic (orange peel, corn cob) or inorganic (silica gel, eggshell) and subjected to a pretreatment process involving drying, grinding, and sieving; inorganic substrates additionally underwent acid activation with citric acid. Surface modification was carried out in ethanolic (APTMS) or aqueous (PEI) media. To assess their suitability and processability as particulate sorbents, drying kinetics, physicochemical properties (FTIR, ζ-potential, pH, conductivity, Boehm titration), and flow characteristics (Carr and Hausner indices) were evaluated. The findings enable a comparative analysis of the functionalization efficiency and elucidate the relationship between substrate type (organic vs. inorganic) and its performance as a modified adsorbent. This approach advances the development of novel sorbent matrices for greenhouse gas mitigation while reinforcing circular economy principles through the valorization of low-cost, readily available waste materials. Full article

Chitosan is a promising biopolymer for drug delivery due to its biocompatibility, biodegradability, and low toxicity. However, its limited dispersibility in water restricts applications, which can be improved through organic acid salts. This study examined how acetic, lactic, glutamic, and citric acids influence the physicochemical, rheological, swelling, bioadhesive, stability, and cytotoxicity properties of chitosan hydrogels. Gels were prepared using varying chitosan-to-acid molar ratios (1:1; 1:1.2 for citrate) and characterized by NMR, FTIR, TGA, and XRD. Despite identical chitosan concentrations (2%, 3%, 3.5%), gels displayed distinct viscosity, swelling, and adhesion profiles depending on the acid. Lactate gels exhibited the most favorable overall performance, combining high viscosity (1555–6665 mPa·s), structural stability, and strong bioadhesion. Citrate gels showed the lowest viscosity (825–3550 mPa·s), cell viability, and stability but the highest bioadhesiveness, likely due to multivalent ionic interactions. Short-term stability tests revealed that low pH accelerated chitosan degradation, leading to viscosity loss up to ~90–95% within 30 days, particularly in citrate hydrogels. Cytotoxicity tests confirmed high biocompatibility, with all formulations maintaining cell viability above 80%. Overall, the findings highlight that organic acid selection is a critical determinant of chitosan gel behavior, offering guidance for tailoring safe, stable, and bioadhesive drug delivery systems. Full article

This study explores the challenge of using anthocyanin-rich natural deep eutectic solvent (NADES) extracts to produce electrospun nanofibers for biodegradable freshness indicators. Red cabbage was extracted with two choline chloride-based NADESs (with citric or lactic acid), modified with 10–50% ethanol to lower viscosity, and compared with a standard 50% ethanol-water solvent. The citric acid NADES with 30% ethanol gave the highest anthocyanin yield (approx. 0.312 mg/mL, more than 20 times higher than the ethanol extract at approx. 0.014 mg/mL). For fiber fabrication, a polymer carrier blend of poly(ethylene oxide) (PEO) and sodium alginate (Alg) was employed, known to form hydrogen-bonded networks that promote chain entanglement and facilitate electrospinning. Despite this, the NADES extracts could not be electrospun into nanofibers, while the ethanol extract produced continuous, smooth fibers with diameters of approximately 100 nm. This highlights a clear trade-off; NADESs improve anthocyanin recovery, but their high viscosity and low volatility prevent fiber formation under standard electrospinning conditions. To leverage the benefits of NADES extracts, future work could focus on hybrid systems, such as multilayer films, core-shell fibers, or microcapsules, where the extracts are stabilized without relying solely on direct electrospinning. In storage tests, ethanol-extract nanofibers acted as effective pH-responsive indicators, showing visible color change from day 4 of meat storage. At the same time, alginate films with NADES extract remained unchanged after 12 days. These results highlight the importance of striking a balance between chemical stability and sensing sensitivity when designing anthocyanin-based smart packaging. Full article

Starch extracted from the domestically cultivated Scala potato variety was explored as a renewable resource for the formulation of biodegradable thermoplastic starch (TPS)/polylactic acid (PLA) blends intended for environmentally friendly food packaging applications. The isolated starch underwent comprehensive physicochemical and structural characterization to assess its suitability for polymer processing. TPS derived from Scala starch was compounded with PLA, both with and without citric acid (CA) as a green compatibilizer to enhance phase compatibility. The resulting polymer blends were systematically analyzed using Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR–ATR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) to evaluate thermal and structural properties. Mechanical performance, water vapor permeability (WVP), water absorption (WA), and biodegradability in soil over 56 days were also assessed. The incorporation of citric acid improved phase miscibility, leading to enhanced structural uniformity, thermal stability, mechanical strength, and barrier efficiency. Bio-degradation tests confirmed the environmental compatibility of the developed blends. Overall, the results demonstrate the potential of Scala-based TPS/PLA systems, particularly those modified with citric acid, as viable candidates for sustainable food packaging, while highlighting the importance of further formulation optimization to balance functional and biodegradative performance. Full article

In this study, MnO₂-CNTs composite support was prepared by citric acid reduction method, and then, Pt nanoparticles were loaded on the surface by ethylene glycol reduction method to obtain a series of Pt/xMnO₂-CNTs catalysts. Structural characterization (TEM, XRD, HRTEM) showed that Pt nanoparticles were uniformly dispersed on the surface of the catalyst with an average particle size of 3.6 nm. Electrochemical tests show that when the content of MnO₂ is 20 wt.%, the Pt/_20wt.%MnO₂-CNTs catalyst has the best methanol oxidation performance, and its mass activity and long-term stability are 4.0 times and 5.41 times that of commercial Pt/C, respectively. The in situ FTIR results showed that MnO₂ promoted the dissociation of water through synergistic effect, generated abundant OH species, accelerated the oxidation of CO intermediates, and inhibited the poisoning of Pt sites. In this study, it is clear that the excellent performance of Pt/xMnO₂-CNTs is due to multiple synergistic effects. Modified carbon nanotubes facilitate proton conduction, Pt nanoparticles effectively activate methanol, and MnO₂ modulates reaction intermediates via its bifunctional mechanism. This comprehensive mechanism understanding provides a theoretical basis for the design of high-performance catalysts for direct methanol fuel cells. Full article

Background/Objectives: Gingival recession poses significant challenges in periodontal therapy, particularly in procedures aimed at achieving predictable root coverage and long-term stability of grafts. Conditioning of the root surface plays a crucial role in improving biomaterial adhesion and facilitating periodontal regeneration. This in vitro study aimed to evaluate the morphological and microroughness alterations of root cementum following different mechanical and chemical conditioning protocols commonly used in mucogingival surgery. Methods: Forty extracted human single-rooted teeth were randomly allocated into eight groups: untreated control, mechanical scaling alone, and scaling combined with ethylenediaminetetraacetic acid (EDTA), citric acid, phosphoric acid, tetracycline, doxycycline, or saline. Surface roughness was measured using contact profilometry, while structural modifications were analyzed via scanning electron microscopy. Results: Statistically significant intergroup differences (p < 0.05) were observed. Baneocin treatment produced the most conservative changes, with limited surface roughness and minimal structural alteration, whereas phosphoric acid, tetracycline, and EDTA caused pronounced demineralization and surface porosity. Citric acid and doxycycline induced moderate alterations, with partial preservation of cementum integrity. The null hypothesis assuming no surface or morphological changes was rejected. Conclusions: These findings indicate that low-aggressiveness agents may achieve an optimal balance between surface decontamination and cementum preservation, which is critical for enhancing graft integration and improving clinical outcomes in root coverage surgery. Full article

This study aimed to assess the effect of acidic storage and simulated brushing on the translucency and color stability of 3D-printed resins for prosthodontic applications. Three 3D printed resin materials—Ceramic Crown (CC), OnX (ONX), and Tough 2 (T2)—were compared with a CAD/CAM milled nano-ceramic resin material (Lava Ultimate, LU). Twelve specimens were fabricated from each material and were allocated into two groups based on the storage medium (water or citric acid), followed by simulated tooth brushing for 3650 cycles. The specimens’ translucency (TP) and color stability (ΔE) were determined using a spectrophotometer. The data was compared using ANOVA, independent student t-tests, and a post hoc Tukey test (p < 0.05). Multiple comparisons of mean differences in TP revealed significant differences between the tested materials (p < 0.001), except for groups CC and ONX. Irrespective of the groups, all materials showed decreased TP values after simulated tooth brushing. Regarding color stability, CC (0.66 ± 0.42) and T2 (1.40 ± 0.34) in acid demonstrated the least and greatest color changes, respectively. The ΔE did not vary between the materials or between the storage media (p > 0.05). Except for T2 and LU in water, the other materials showed ΔE values below the perceptibility threshold of 1.2. The material type and storage media affected the translucency of the tested materials. However, regardless of the material type and storage media, there was no discernible impact on the color change of the tested materials. Full article

Cellulose nanofibril (CNF)-based hydrogels, owing to their sustainability, biocompatibility, and versatile mechanical properties, are promising for biomedical applications. This review analyzes the recent advances and biomedical applications of CNF hydrogels. CNF hydrogels can be prepared via physical and chemical crosslinking. Physical crosslinking involves surface charge density control, pH manipulation, and flow-based processing to generate stable networks, whereas chemical crosslinking employs agents such as epichlorohydrin and citric acid to form permanent covalent bonds. These approaches enable precise control over hydrogel properties, including mechanical strength, porosity, and stimuli responsiveness. CNF hydrogels are particularly promising in drug delivery systems and tissue engineering. CNFs as drug delivery vehicles offer enhanced bioavailability and drug loading capacity owing to their open pore structure and large surface area. Recent developments in stimuli-responsive and injectable CNF hydrogels have enabled controlled drug release and improved targeting capabilities. Moreover, CNF hydrogels serve as effective scaffolds for cell growth and tissue regeneration, with applications in cartilage engineering and wound healing. Integrating CNF hydrogels with 3D bioprinting technology has generated complex tissue structures. However, several challenges remain, including the need for the standardization of toxicology assessments, optimization of large-scale production processes, and development of sophisticated control mechanisms for drug delivery. Future research should advance manufacturing technologies, improve long-term stability, and develop standardized testing protocols for regulatory compliance. Full article

Lipid peroxidation driven by polyunsaturated fatty acid (PUFA) oxidation compromises feed quality and animal health. Single antioxidants (e.g., ethoxyquin (EQ), butylated hydroxytoluene (BHT)) face limitations including dose-dependent toxicity, bioaccumulation risks, and inadequate protection against multistage oxidation. Composite systems leveraging complementary mechanisms offer a promising alternative. This study evaluated synergistic efficacy of rationally formulated composite antioxidants (combining synthetic radical scavengers and metal chelators) versus single-component systems in enhancing lipid oxidative stability in high-fat animal feed. The basal diet containing oxidized oil served as the control group (CON). Seven groups were supplemented with the basal diet as follows: Treatment A, 36 g/ton Butylated Hydroxytoluene (BHT); Treatment B, 60 g/ton Ethoxyquin (EQ); Treatment C, 132 g/ton EQ; Treatment D, 10 g/ton EQ + 12 g/ton BHT; Treatment E, 10 g/ton EQ + 12 g/ton BHT + 6 g/ton Citric acid (CA); Treatment F, 20 g/ton EQ + 6 g/ton BHT + 6 g/ton CA; and treatment G, 2 g/ton EQ + 25 g/ton BHT + 6 g/ton CA. Oxidative stability was assessed over a 10-week period under natural storage (T0-T10) and acute thermal stress (120 °C drying for 2 h followed by ambient storage; HT0 to HT10). Oxidative stability was assessed via: antioxidant capacity (DPPH (2,2-Diphenyl-1-picrylhydrazyl)/ABTS (2,2′-Azinobis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging, total antioxidant capacity), physical indices: Color (L*, a*, b*), and chemical oxidation markers: conjugated dienes (CD), peroxide value (PV), p-anisidine value (p-AV), malondialdehyde (MDA), acid value (AV), total oxidation (TOTOX). Superior synergistic performance of the ternary blend (Treatment E) was demonstrated versus singles (A/B/C). Retention of radical scavenging capacity was significantly enhanced, with greater stability observed under accelerated storage. Primary oxidation (PV) and secondary oxidation (MDA, p-AV) were most effectively suppressed by Treatment E. Superior color stability (minimal L* change) was maintained under thermal stress. The lowest TOTOX values were achieved across all conditions by Treatment E. Stage-specific vulnerabilities were shown by single antioxidants (BHT volatilization; pro-oxidative effects of EQ at high doses). Comprehensive, temperature-resilient protection was delivered collectively by the synergistic EQ+BHT+CA system (Treatment E) via combined radical quenching and metal chelation. The inherent limitations of individual antioxidants were effectively overcome by the optimized composite, enabling reduced total dosage while substantially extending the lipid oxidative stability period. Full article

This study aimed to develop a reliable method for profiling reducing sugars in honey using capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIF). Reducing sugars were derivatized with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) in the presence of 2-picoline borane, a safer alternative to sodium cyanoborohydride. Key parameters influencing the derivatization efficiency—temperature, pH, incubation time, and reagent concentrations—were systematically optimized. The highest labeling efficiency for glucose, mannose, and maltose was achieved at 50 °C in 0.5 M citric acid with 0.1 M APTS, while fructose showed low reactivity due to its ketose structure. To reduce the background signal from excess reagents, three cleanup strategies were evaluated. Liquid–liquid extraction with ethyl acetate effectively removed unreacted APTS without significant analyte loss, whereas solid-phase extraction and microextraction caused substantial losses of hydrophilic sugars. The method showed good linearity (0.5–10 mM, R² > 0.994), precision (RSD 0.81–13.73%), and accuracy (recoveries 93.47–119.75%). Stability studies indicated that sugar standards should be stored at –20 °C. The method was successfully applied to the analysis of four nectar honeys—rapeseed, acacia, phacelia, and dandelion—revealing differences in glucose and fructose content related to botanical origin. The results confirm the suitability of CZE-LIF for sensitive and selective carbohydrate analyses in complex food matrices. Full article