Search Results (13)

Mitragyna speciosa (kratom) is a traditional medicinal plant rich in bioactive alkaloids and phenolics, known for their antioxidant and anti-aging properties. This study aimed to develop nanoparticle-based topical gels from ethanolic extracts of four kratom varieties, including Kan Daeng (KD), Hang Kang (HK), Tai Bai-yao (KY), and Kan Keaw (KG). Kratom NPs were prepared using a solvent displacement method. The resulting nanoparticles (NPs) exhibited sizes of 201.9–256.2 nm, polydispersity indices (PDI) below 0.3, and a zeta potential between −22.6 and −29.6 mV. The phytochemical analysis revealed that KG and KY extracts contained the highest total phenolic content (TPC) and total flavonoid content (TFC), which were mostly retained after NP formulation. The HPLC analysis confirmed HK as the richest source of mitragynine (9.97 ± 0.10% w/w), while NP formulations displayed slightly reduced levels. Antioxidant activities assessed by DPPH, ABTS, and FRAP assays revealed enhanced radical scavenging in nanoparticle formulations, with IC₅₀ values ranging from 151.23 to 199.87 µg/mL (DPPH) and 207.37 to 272.83 µg/mL (ABTS). All formulations exhibited a significant inhibition of collagenase (80.56 ± 1.60 to 97.23 ± 0.29%), elastase (45.46 ± 6.53 to 52.19 ± 1.20%), and hyaluronidase (83.23 ± 2.34 to 91.67 ± 3.56%), with nanoparticle forms showing superior enzyme inhibition. Notably, nanoparticle formulations exhibited superior inhibitory effects compared to crude extracts. HaCaT cytotoxicity tests confirmed high biocompatibility (IC₅₀ > 700 µg/mL), especially for KD and KG NPs. The NP-loaded gels demonstrated acceptable physicochemical stability after heating/cooling cycle testing, with pH (7.27 to 7.88), viscosity (10.719 to 12.602 Pa·s), and favorable visual and textural properties. In summary, KG and KY cultivars emerged as the most promising cosmeceutical candidates due to their superior phytochemical content, antioxidant capacity, enzyme-inhibitory activities, and formulation performance. These findings support the potential use of KG NP and KY NP-loaded gels as multifunctional cosmeceutical agents for antioxidant protection, anti-aging, and skin rejuvenation. Full article

Nanoparticles (NPs) have revolutionized biomedical and pharmaceutical applications due to their unique physicochemical properties. However, their widespread use has raised concerns regarding their potential toxicity, particularly mediated by oxidative stress mechanisms. This redox imbalance, primarily driven by the overproduction of reactive oxygen species (ROS), plays a central role in NP-induced toxicity, leading to cellular dysfunction, inflammation, apoptosis, and genotoxicity. Zebrafish (Danio rerio) have emerged as a powerful in vivo model for nanotoxicology, offering advantages such as genetic similarity to humans, rapid development, and optical transparency, allowing real-time monitoring of oxidative damage. This review synthesizes current findings on NP-induced oxidative stress in zebrafish, highlighting key toxicity mechanisms and case studies involving metallic (gold, silver, copper), metal oxide (zinc oxide, titanium dioxide, iron oxide), polymeric, and lipid-based NPs. The influence of NP physicochemical properties, such as size, surface charge, and functionalization, on oxidative stress responses is explored. Additionally, experimental approaches used to assess ROS generation, antioxidant enzyme activity, and oxidative damage biomarkers in zebrafish models are examined. In addition to toxicity concerns, pharmaceutical applications of antioxidant-modified NPs are evaluated, particularly their potential in drug delivery, neuroprotection, and disease therapeutics. Notably, studies show that curcumin- and quercetin-loaded nanoparticles enhance antioxidant defense and reduce neurotoxicity in zebrafish models, demonstrating their promise in neuroprotective therapies. Furthermore, cerium oxide nanoparticles, which mimic catalase and SOD enzymatic activity, have shown significant efficacy in reducing ROS and protecting against oxidative damage. Challenges in zebrafish-based nanotoxicology, the need for standardized methodologies, and future directions for optimizing NP design to minimize oxidative stress-related risks are also discussed. By integrating insights from toxicity mechanisms, case studies, and pharmaceutical strategies, this review supports the development of safer and more effective nanoparticle-based therapies while addressing the challenges of oxidative stress-related toxicity. Full article

Biodiesel is a mixture of fatty acid alkyl esters (FAAEs) mainly produced via transesterification reactions among triglycerides and short-chain alcohols catalyzed by chemical catalysts (e.g., KOH, NaOH). Lipase-assisted enzymatic transesterification has been proposed to overcome the drawbacks of chemical synthesis, such as high energy consumption, expensive separation of the catalyst from the reaction mixture and production of large amounts of wastewater during product separation and purification. However, one of the main drawbacks of this process is the enzyme cost. In recent years, nano-immobilized lipases have received extensive attention in the design of robust industrial biocatalysts for biodiesel production. To improve lipase catalytic efficiency, magnetic nanoparticles (MNPs) have attracted growing interest as versatile lipase carriers, owing to their unique properties, such as high surface-to-volume ratio and high enzyme loading capacity, low cost and inertness against chemical and microbial degradation, biocompatibility and eco-friendliness, standard synthetic methods for large-scale production and, most importantly, magnetic properties, which provide the possibility for the immobilized lipase to be easily separated at the end of the process by applying an external magnetic field. For the preparation of such effective magnetic nano-supports, various surface functionalization approaches have been developed to immobilize a broad range of industrially important lipases. Immobilization generally improves lipase chemical-thermal stability in a wide pH and temperature range and may also modify its catalytic performance. Additionally, different lipases can be co-immobilized onto the same nano-carrier, which is a highly effective strategy to enhance biodiesel yield, specifically for those feedstocks containing heterogeneous free fatty acids (FFAs). This review will present an update on the use of magnetic iron oxide nanostructures (MNPs) for lipase immobilization to catalyze transesterification reactions for biodiesel production. The following aspects will be covered: (1) common organic modifiers for magnetic nanoparticle support and (2) recent studies on modified MNPs-lipase catalysts for biodiesel production. Aspects concerning immobilization procedures and surface functionalization of the nano-supports will be highlighted. Additionally, the main features that characterize these nano-biocatalysts, such as enzymatic activity, reusability, resistance to heat and pH, will be discussed. Perspectives and key considerations for optimizing biodiesel production in terms of sustainability are also provided for future studies. Full article

Marigold flower is a traditionally used plant material topically applied on the skin due to its anti-inflammatory properties and antibacterial activity. This potential of action justifies the implementation of marigold extract in nanofiber scaffolds based on poly-vinylpyrrolidone/hydroxypropyl-β-cyclodextrin (PVP/HPβCD) and polycaprolactone/polyvinylpyrrolidone (PCL/PVP) obtained by electrospinning for wound treatment. Using SEM, the morphology of electrospun scaffolds showed a fiber diameter in the range of 298–527 nm, with a uniform and bead-free appearance. ATR-FTIR spectroscopy confirmed the presence of marigold extracts in nanofibrous scaffolds. The composition of the nanofibers can control the release; in the case of PVP/HPβCD, immediate release of 80% of chlorogenic acid (an analytical and functional marker for marigold extract) was achieved within 30 min, while in the case of PCL/PVP, the controlled release was achieved within 24 h (70% of chlorogenic acid). All systems showed weak antibacterial activity against skin and wound-infecting bacteria Staphylococcus aureus (MIC 100 mg/mL), and Pseudomonas aeruginosa (MIC 200 mg/mL) and yeasts Candida albicans (MIC 100 mg/mL). Analysis of the effect of different scaffold compositions of the obtained electrofibers showed that those based on PCL/PVP had better wound healing potential. The scratch was closed after 36 h, compared to the 48 h required for PVP/HPβCD. Overall, the study shows that scaffolds of PCL/PVP nanofibers loaded with classic marigold extract have the best potential as wound dressing materials because of their ability to selectively modulate inflammation (via inhibition of hyaluronidase enzyme) and supportive antimicrobial properties, thereby aiding in the early stages of wound healing and repair. Full article

The thermal storage performance, cost, and stability of phase-change materials (PCMs) are critical factors influencing their application in the field of thermal energy storage. Porous carbon, with its excellent support, thermal conductivity, and energy storage properties, is considered one of the most promising support matrix materials. However, the simple and efficient synthesis of high-performance and highly active bio-based materials under mild conditions still faces challenges. In our work, a novel method for preparing new functional composite phase-change materials based on enzyme treatment technology and using waste walnut green husk biomass and polyethylene glycol as raw materials was developed. The enzymatic treatment method exposes the internal structure of the walnut green husk, followed by the adjustment of the calcination temperature to increase the adsorption sites of the biochar, thereby stabilizing polyethylene glycol (PEG). The porous properties of walnut green husk biochar effectively regulate the phase-change behavior of polyethylene glycol. In the biochar carbonized at 600 °C, the PEG loading reached 72.09%, and the absorption heat of the solid–solid phase-change material (SSPCM) reached 194.76 J g⁻¹. This work not only enriches the application of biomass in heat storage but also demonstrates the broad prospects of SSPCMs in solar thermal utilization. Full article

The lipases from Thermomyces lanuginosus (TLL) and Candida antarctica (B) (CALB) were immobilized on octyl-agarose beads at 1 mg/g (a loading under the capacity of the support) and by overloading the support with the enzymes. These biocatalysts were compared in their stabilities in 10 mM of sodium phosphate, HEPES, and Tris-HCl at pH 7. Lowly loaded CALB was more stable than highly loaded CALB preparation, while with TLL this effect was smaller. Phosphate was very negative for the stability of the CALB biocatalyst and moderately negative using TLL at both loadings. The stability of the enzymes in HEPES and Tris-HCl presented a different response as a function of the enzyme loading (e.g., using lowly loaded CALB, the stabilities were similar in both buffers, but it was clearly smaller in HEPES using the highly loaded biocatalysts). Moreover, the specific activity of the immobilized enzymes versus p-nitrophenol butyrate, triacetin and R- or S-methyl mandelate depended on the buffer, enzyme loading, and interaction between them. In some cases, almost twice the expected activity could be obtained using highly loaded octyl-CALB, depending on the buffer. A co-interaction between the effects on enzyme activity and the specificity of support enzyme loading and buffer nature was detected. Full article

Metal–organic framework materials (MOFs) and their derivatives are considered ideal immobilization carrier materials because of their large specific surface area, high porosity and excellent structural designability. Among them, ZIF-8 has great potential for immobilization of enzymes due to mild synthesis conditions, and good biocompatibility. However, conventional ZIF-8 crystals have poor separation and recovery efficiency due to their small pore size and poor acid stability, greatly limiting their application in enzyme immobilization and further application. Although the carbonization of ZIF-8 by pyrolysis has been shown to be one of the approaches that can enhance its chemical stability, this still does not effectively solve the problem of the difficulty of recycling. Herein, we developed a strategy of pre-carbonization immersion (immersion in aqueous FeSO₄ solution before carbonization) to synthesize ordered macroporous ZIF-8-derived carbon materials with stable ferromagnetism (denoted as CZ-x-M-y, where x denotes the carbonization temperature and y denotes the concentration of the impregnated FeSO₄ solution) and used them to immobilize lipases for biodiesel production. XRD analysis showed that the magnetic properties in the materials came from Fe₃C species. We found that the magnetic carbon materials obtained by carbonization at 600 °C showed the best immobilization effect, where CZ-600-M-0.3 (using 0.3 mol·L⁻¹ FeSO₄ aqueous solution to soak ZIF-8 and carbonized at 600 °C) had the highest enzyme loading of 183.04 mg·g⁻¹, which was 49.7% higher than that of the non-magnetic CZ-600. In addition, CZ-600-M-0.5 maintained the highest enzyme activity, which was 81.9% of the initial activity, after five batches of reuse. The stable magnetic support materials reported in this study have promising potential for the industrial application of immobilized lipase. Full article

Because of the health benefits and economic opportunities, extracting bioactive peptides from plant proteins, often food processing by-products, garners significant interest. However, the high enzyme costs and the emergence of bitter peptides have posed significant challenges in production. This study achieved the immobilization of Alcalase and Flavorzyme using cost-effective SiO₂ microparticles. Mussel-inspired chemistry and biocompatible polymers were employed, with genipin replacing glutaraldehyde for safer crosslinking. This approach yielded an enzyme loading capacity of approximately 25 mg/g support, with specific activity levels reaching around 180 U/mg for immobilized Alcalase (IA) and 35 U/mg for immobilized Flavorzyme (IF). These immobilized proteases exhibited improved activity and stability across a broader pH and temperature range. During the hydrolysis of soy proteins, the use of immobilized proteases avoided the thermal inactivation step, resulting in fewer peptide aggregates. Moreover, this study applied peptidomics and bioinformatics to profile peptides in each hydrolysate and identify bioactive ones. Cascade hydrolysis with IA and IF reduced the presence of bitter peptides by approximately 20%. Additionally, 50% of the identified peptides were predicted to have bioactive properties after in silico digestion simulation. This work offers a cost-effective way of generating bioactive peptides from soy proteins with reducing potential bitterness. Full article

Enzymatic conversion of pharmaceutically active ingredients (API), using immobilized enzymes should be considered as a promising industrial tool due to improved reusability and stability of the biocatalysts at harsh process conditions. Therefore, in this study horseradish peroxidase was immobilized into sodium alginate capsules and then trapped into poly(vinyl chloride) electrospun fibers to provide additional enzyme stabilization and protection against the negative effect of harsh process conditions. Due to encapsulation immobilization, 100% of immobilization yield was achieved leading to loading of 25 μg of enzyme in 1 mg of the support. Immobilized in such a way, enzyme showed over 80% activity retention. Further, only slight changes in kinetic parameters of free (K_m = 1.54 mM) and immobilized horseradish peroxidase (K_m = 1.83 mM) were noticed, indicating retention of high catalytic properties and high substrate affinity by encapsulated biocatalyst. Encapsulated horseradish peroxidase was tested in biodegradation of two frequently occurring in wastewater API, sulfamethoxazole (antibiotic) and carbamazepine (anticonvulsant). Over 80% of both pharmaceutics was removed by immobilized enzyme after 24 h of the process from the solution at a concentration of 1 mg/L, under optimal conditions, which were found to be pH 7, temperature 25 °C and 2 mM of H₂O₂. However, even from 10 mg/L solutions, it was possible to remove over 40% of both pharmaceuticals. Finally, the reusability and storage stability study of immobilized horseradish peroxidase showed retention of over 60% of initial activity after 20 days of storage at 4 °C and after 10 repeated catalytic cycles, indicating great practical application potential. By contrast, the free enzyme showed less than 20% of its initial activity after 20 days of storage and exhibited no recycling potential. Full article

Silica xerogels have been proposed as a potential support to immobilize enzymes. Improving xerogels’ interactions with such enzymes and their mechanical strengths is critical to their practical applications. Herein, based on the mussel-inspired chemistry, we demonstrated a simple and highly effective strategy for stabilizing enzymes embedded inside silica xerogels by a polydopamine (PDA) coating through in-situ polymerization. The modified silica xerogels were characterized by scanning and transmission electron microscopy, Fourier tranform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and pore structure analyses. When the PDA-modified silica xerogels were used to immobilize enzymes of Candida antarctica lipase B (CALB), they exhibited a high loading ability of 45.6 mg/g_support, which was higher than that of immobilized CALB in silica xerogels (28.5 mg/g_support). The immobilized CALB of the PDA-modified silica xerogels retained 71.4% of their initial activities after 90 days of storage, whereas the free CALB retained only 30.2%. Moreover, compared with the immobilization of enzymes in silica xerogels, the mechanical properties, thermal stability and reusability of enzymes immobilized in PDA-modified silica xerogels were also improved significantly. These advantages indicate that the new hybrid material can be used as a low-cost and effective immobilized-enzyme support. Full article

A highly effective method was developed to functionalize ceramic supports (Al₂O₃ powders and membranes) using newly synthesized spacer molecules. The functionalized materials were subsequently utilized for Candida antarctica lipase B enzyme immobilization. The objective is to systematically evaluate the impact of various spacer molecules grafted onto the alumina materials will affect both the immobilization of the enzymes and specific material surface properties, critical to enzymatic reactors performance. The enzyme loading was significantly improved for the supports modified with shorter spacer molecules, which possessed higher grafting effectiveness on the order of 90%. The specific enzyme activity was found to be much higher for samples functionalized with longer modifiers yielding excellent enantioselectivity >97%. However, the enantiomeric ratio of the immobilized lipase was slightly lower in the case of shorter spacer molecules. Full article

Two magnetic supports with different morphologies and particle sizes were designed and prepared for cellulase immobilization based on chitosan and industrial by-product magnetic coal fly ash (MCFA). One was prepared by coating chitosan onto spherical MCFA particles to form non-porous MCFA@chitosan gel microcomposites (Support I) with a size of several micrometers, and the other was prepared using the suspension method to form porous MCFA/chitosan gel beads (Support II) with a size of several hundred micrometers. Cellulase was covalent binding to the support by glutaraldehyde activation method. The morphology, structure and magnetic property of immobilized cellulase were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and a vibrating-sample magnetometer. The cellulase loading on Support I was 85.8 mg/g with a relatlvely high activity recovery of 76.6%, but the immobilized cellulase exhibited low thermal stability. The cellulase loading on Support II was 76.8 mg/g with a relative low activity recovery of 51.9%, but the immobilized cellulase showed high thermal stability. Cellulase immobilized on Support I had a glucose productivity of 219.8 mg glucose/g CMC and remained 69.9% of the original after 10 cycles; whereas the glucose productivity was 246.4 mg glucose/g CMC and kept 75.5% of its initial value after 10 repeated uses for Support II immobilized cellulase. The results indicate that the two supports can be used as cheap and effective supports to immobilize enzymes. Full article

The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V_max, k_cat and k_cat/K_m, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media. Full article