Glutaraldehyde Research Articles

Development, in vitro and ex vivo characterization of lamotrigine-loaded bovine serum albumin nanoparticles using QbD approach

The present study aimed to prepare and optimize lamotrigine-loaded bovine serum albumin nanoparticles (LAM-NP) using the Quality by Design (QbD) approach and to investigate both the in vitro and ex vivo effects of different cross-linking agents glutaraldehyde (GLUT), glucose (GLUC) and 1-(3-dimethylaminutesopropyl)-3-ethylcarbodiimide hydrochloride (EDC) on intranasal applicability. Cross-linked LAM-NP from EDC (NP-EDC-1) showed the lowest Z-average value (163.7 ± 1.9 nm) and drug encapsulation efficacy (EE%) of 97.31 ± 0.17%. The drug release of GLUC cross-linked LAM-NP (NP-GLUC-9), glutaraldehyde cross-linked LAM-NP (NP-GLUT-2), and NP-EDC-1 at blood circulation conditions was higher than the initial LAM. The results of the blood-brain barrier parallel artificial membrane permeability assay (BBB-PAMPA) showed an increase in the permeability of LAM through the BBB with NP-GLUC-9 and an increase in flux with all selected formulations. The ex vivo study showed that LAM diffusion from the selected formulations through the human nasal mucosa was higher than in case of initial LAM. The cytotoxicity study indicated that BSA-NP reduced LAM toxicity, and GLUC 9 mM and EDC 1 mg could be alternative cross-linking agents to avoid GLUT 2% v/v toxicity. Furthermore, permeability through Caco-2 cells showed that nasal epithelial transport/absorption of LAM was improved by using BSA-NPs. The use of BSA-NP may be a promising approach to enhance the solubility, permeability through BBB and decrease the frequency of dosing and adverse effects of LAM.

Studies on the preparation of a sufficient carrier from egg protein and carrageenan for cellulase with optimization and application

Egg protein (EP) concentration, pH, and glutaraldehyde (GA) concentration were optimized using Box Behnken design (BBD) to prepare GA-EP-Carr (Carrageenan) beads as a carrier for Aspergillus niger MK981235 cellulase. It was recommended that the concentrations of GA, and EP be set at 11.21% (w/v), 8% (w/w), and pH 3, respectively. It was determined that 60 °C and 2% for free form and 60 °C and 3% for im-cellulase were the optimum temperature and CMC concentration parameters for maximum enzyme activity. Free and im-cellulase were determined to have Km and Vmax of 2.22 mg.ml-1 and 1.76 µmol.ml-1.min-1, and 4.55 mg.ml-1 and 3.33 µmol.ml-1.min-1, respectively. Covalent coupling of A. niger cellulase to GA- EP- Carr beads improved its thermodynamic parameters T1/2 and D-values by 2.48, 2.01, and 2.36 times at 40, 50, and 60 °C, respectively. GA- EP- Carr im-cellulase was 100% active for 60 days at 4 °C and can be used for CMC hydrolysis for 20 successive cycles. GA- EP- Carr im-cellulase showed remarkable efficiency in the clarification of mango, peach, grape, and orange juices emphasized by TSS (total soluble solids), turbidity, and reducing sugar measurements for 3 successive cycles. GA- EP- Carr im-cellulase can be applied with high efficiency in juice industry.

Insight into the Mechanism of Chemically Stabilizing Collagen

Developing chromium-free tanning agents has attracted much attention due to the potential risks of chromium, however, no alternative can endow leather with the same hydrothermal stability as chromium so far. Indeed, the mechanism of chemically stabilizing collagen still remains unclear. This work used collagen fiber as an adsorbent to explore the source of leather stability by the adsorption thermodynamics of typical tanning agents such as Cr(III), Al(III), glutaraldehyde (GA), and polyphenols (epicatechin, EC). The consistency in optimal conditions among tanning reactions and adsorption processes supported the rationality of the adsorption method. The adsorption for Cr(III) has a slightly lower Gibbs free energy change of -35.82 kJ.mol-1 when compared to other tanning agents, confirming its superiority in leather stability. Significantly, the highest entropy increase of 305.60 and enthalpy change of 61.36 kJmol-1 are observed in adsorbing Cr(III). The adsorption processes of Cr(III), Al(III), and GA are endothermic spontaneous reactions, and the main driving force is entropy, whereas that of EC is an exothermic spontaneous reaction driven by enthalpy and entropy together. Obviously, an increase in entropy is particularly important in the tanning reaction for the stability of products. Thus, the binding water released from collagen fibers was identified to play a crucial role in the source of the stability of tanning agents. This work is not only conducive to deepening the understanding of tanning mechanisms, but also beneficial to developing novel chrome-free tanning agents.

Detection and characterization of pathogenic Bacillus haynesii from Tribulus terrestris extract: ways to reduce its levels.

Plant parts such as roots, bark, leaves, flowers, and fruits that hold ethnopharmacological significance are naturally prone to microbial contamination, influenced by environmental factors like moisture and humidity. This study focuses on assessing the microbial load in the raw material of Tribulus terrestris (TT). The primary bacterium isolated from the pulverized raw material was identified as Bacillus haynesii through 16S rRNA sequencing. Biochemical assays revealed the organism's ability to utilize lysine and ornithine, produce urease, and generate hydrogen sulfide. The bacterium exhibited resistance to multiple antibiotics and caused 21.5% hemolysis in RBC lysis assays. To reduce microbial contamination, Glutaraldehyde (GA) and polyhexamethylene biguanide (PHMB) were tested, with GA at 1% reducing the microbial load by 99% without affecting the yield (0.5%) or bioactive saponin content. High-Performance Liquid Chromatography (HPLC) confirmed the absence of residual GA, ensuring an eco-friendly and safe process. This highlights the importance of quality control measures, including Hazard Analysis and Critical Control Points (HACCP) regulations, in maintaining the integrity of herbal extracts.

Development and Characterization of a Gelatin-Based Photoactive Hydrogel for Biomedical Application

Photoactive hydrogels facilitate light-triggered photochemical processes, positioning them as innovative solutions in biomedical applications, especially in antimicrobial photodynamic therapy. This study presents a novel methylene blue-based photoactive hydrogel designed as a topical gel solution to overcome the limitations of traditional pad-based systems by offering enhanced adaptability to irregular wound surfaces, uniform photosensitizer distribution, and deeper therapeutic light penetration. This study investigated the development of hydrogels by cross-linking gelatin with glutaraldehyde (GA) and incorporating methylene blue (MB) to investigate the effects of cross-linking density, network structure, and small molecule inclusion on hydrogel properties. The results showed that while glutaraldehyde concentration influenced swelling behavior and network structure, the inclusion of MB altered these properties, particularly reducing swelling and MB retention at higher GA concentrations. Rheological and thermal analyses confirmed that higher GA concentrations made the hydrogels more rigid, with MB influencing both mechanical and thermal properties. Additionally, the hydrogels exhibited enhanced antimicrobial properties through increased reactive oxygen species production, particularly in light-activated conditions, demonstrating the potential of MB-based photoactive hydrogels for improving antimicrobial efficacy, especially against S. aureus, E. coli, and C. albicans, offering as a possible alternative to traditional antimicrobial treatments.

Sustainable development of hybrid aerogels from surplus gelatin and chitosan for enhancing the dissolution rate of clotrimazole

AbstractHybrid aerogels were developed using surplus gelatin from the pharmaceutical industry and chitosan to address gelatin waste and enhance drug solubility. Glutaraldehyde (GA) was used as a cross‐linking agent to establish a porous network within hydrogels, which were solvent‐exchanged with ethanol and freeze‐dried to form aerogels. These aerogels served as carriers for clotrimazole, a poorly water‐soluble antifungal drug. The impact of the volume ratio of GA to the chitosan–gelatin mixture (ranging from 10% to 40% GA) and chitosan‐to‐gelatin ratios (1:1–1:4) on clotrimazole content and dissolution rate was investigated. Aerogels cross‐linked with 20% GA achieved a drug release rate threefold higher than unprocessed clotrimazole at 180 min, with all aerogels outperforming xerogels and raw clotrimazole. XRD and DSC analyses revealed reduced clotrimazole crystallinity, indicating its transition to an amorphous form. Antifungal tests against Trichophyton mentagrophytes ATCC 9533 showed inhibition zones of 83.5 ± 2.1 mm and 82.5 ± 3.5 mm for aerogels with chitosan‐to‐gelatin ratios of 1:1 and 1:4, respectively, comparable to unprocessed clotrimazole (92.5 ± 3.5 mm). This study demonstrates the potential of gelatin waste and chitosan‐based aerogels as sustainable carriers for poorly water‐soluble drugs, advancing pharmaceutical applications and environmental sustainability.Highlights A hybrid aerogel composed of chitosan and surplus gelatin was fabricated. GA amount and chitosan‐to‐gelatin ratio impacted drug content and dissolution. Clotrimazole‐loaded aerogels dissolved faster than the pure drug and xerogels. The 1:1 and 1:4 chitosan–gelatin aerogels had similar antifungal efficacy.

Preparation of bovine serum albumin nanospheres via desolvation: a study of synthesis, characterization, and aging.

Serum albumin has myriad uses in biotechnology, but its value as a nanocarrier or nanoplatform for therapeutics is becoming increasingly important, notably with albumin-bound chemotherapeutics. Another emerging field is the fabrication of biopolymeric nanoparticles using albumin as a building block to achieve highly-tunable nonimmunogenic capsules or scaffolds that may be cheaply and reliably produced. The aim of this study was to characterize and optimize the desolvation process used for fabrication of albumin nanoparticles under ambient conditions, studying both glutaraldehyde (GT) and glucose (GLU) as crosslinking agents and the effect of various synthesis conditions including pH, electrolyte concentration, and rate of desolvation on particle size and stability. Particle size, polydispersity index, and zeta potential were investigated, morphology was examined using scanning electron microscopy (SEM), and long-term stability and degradation modes were studied using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was determined that the optimized synthesis procedure for synthesis of Bovine Serum Albumin (BSA) nanoparticles at the investigated scale under ambient conditions was addition of ethanol at a rate of 0.625 mL min-1via infusion against the vial wall and a pH of 9 with the addition of no other electrolytes. Optimized BSA nanoparticles were synthesized at a size of 86 ± 3.7 nm (σ = 1.85) using glutaraldehyde as a crosslinker and a size of 92 ± 1.9 nm (σ = 0.95) using glucose as a crosslinker with polydispersity indices of 0.08 and 0.05, respectively. Nanoparticles synthesized via the optimized procedure, using both crosslinkers, were found to maintain colloidal stability significantly longer than cases previously reported in the literature, with insignificant changes in hydrodynamic size many months after synthesis.

Development of a Novel Human Serum Albumin-Based Tool for Effective Drug Discovery: The Investigation of Protein Quality and Immobilization.

The binding ability of human serum albumin (HSA) on active pharmaceutical ingredients (APIs) is one of the most important parameters in the early stages of drug discovery. In this study, an immobilized HSA-based tool was developed for the rapid and easy in vitro screening of API binding. The work explored the serious incompleteness in the identification of HSA used for in vitro screening published in the last five years. To mitigate this problem, a comprehensive analysis and immobilization studies were performed on the most used HSA types. Serious differences in the colloidal stability of HSAs and their API binding ability on a selected set of APIs were observed. HSAs were immobilized on magnetic nanoparticles with glutardialdehyde (GDA) or cyclohexyl-diglycidyl ether (CDGE) linkers, which have never been used for HSA immobilization before. The HSA-MNP-CDGE complexes achieved a higher immobilization yield and preserved API binding ability; however, the esterase-like enzymatic activity of HSA reduced significantly.

COMPARATIVE ANALYSIS OF PULMONARY ARTERY CONDUITS IN CHILDREN

HighlightsThe review presents the analysis of long-term outcomes of implantation of the most common types of conduits in children. Predictors of the development of dysfunction and infective endocarditis are presented. Aim. To analyze the function of the available types of conduits in pediatric group of patients who underwent right ventricular outflow tract (RVOT) reconstruction.Methods. The retrospective study included patients between 0 and 18 years old who underwent RVOT reconstruction using conduits between 2000 and 2017. Clinical records and imaging data were analyzed.Results. A total of 400 patients underwent implantation of 495 conduits including glutaraldehyde (GA)-treated bovine jugular vein (contegra) (n = 181); GA-treated xenopericardial conduit (BioLAB) (n = 84); diepoxyde (DE)-treated xenopericardial conduit with porcine aortic root (AB-composite) (n = 65); DE-treated xenopericardial conduit (Pilon) (n = 32) and cryopreserved pulmonary homograft (n = 135). Primary implantation was made in 383 cases (77.3%) and conduit reimplantation was made in 112 cases (22.5%). Median follow-up was 79.9 (42.6; 110.7) months. Redo surgery with conduit replacement was made in 41 (8.5%) cases, of these, 6 (2.1%) conduits were replaced due to thrombosis, endocarditis was diagnosed in 14 patients (4.8%), there were no statistical differences between the groups. Younger age was associated with high risk of early dysfunction (OR 0.97; 95% CI 0.96–0.99, p = 0.03). Multivariate analysis revealed that the type of conduit was not a risk factor (OR 0,86; 95% CI 0,64–1,15; p = 0,64). Severe calcification was the main predictor of conduit-associated mortality (OR 0.02; 95% CI 0.002–0.34; p = 0.005).Conclusion. Incidence of reintervention due to conduit dysfunction is still high in pediatric group and is not associated with type of conduit. All types of available conduits showed comparable rates of dysfunction. Risk of developing conduit-associated infective endocarditis also does not depend on the type of implanted graft.

Glutaraldehyde functionalized reduced graphene oxide based resistive sensors for detection of PCA3.

Prostate cancer antigen 3 (PCA3) has emerged as a critical biomarker for the early detection of prostate cancer, complementing the traditional prostate-specific antigen (PSA) testing. This research presents a novel resistive sensor based on reduced graphene oxide (RGO) functionalized with glutaraldehyde (GA)/complementary single-stranded DNA (ss-DNA) for the detection of the PCA3 RNA. The device was meticulously characterized at each fabrication step to confirm the successful integration of the various layers on the sensor device, utilizing atomic force microscopy (AFM) which confirmed the increase in the thickness of the sensor from ∼1.4 nm (only RGO) to ∼25 nm for the RGO-GA/ss-DNA/PCA3 device. Field emission scanning electron microscopy exhibited a change in the surface morphology after each step of device fabrication and testing. Fourier-transform infrared (FTIR) spectroscopy was conducted to confirm the presence of functional groups in each component of the sensor. The fabricated resistive sensor demonstrated mean response ranging from 1.203 to 59.44% for 0.1 to 100 ng mL-1 PCA3 RNA. Notably, the device exhibited stability over a period of two weeks and displayed high selectivity for PCA3. The developed RGO-GA/ss-DNA/PCA3 sensor was tested with RNA extracted from multiple prostate cancer cell lines and other cancer cell lines and demonstrated response only to RNA extracted from LNCaP as it was the only cell line expression of PCA3. The findings from the developed sensor were cross-validated with the observations of a semi quantitative polymerase chain reaction (qPCR), and were found to be closely matched.

New insight into the protective effect of Citrullus colocynthis loaded with ZnONP cream on glutaraldehyde-induced dermatitis in health care workers

Glutaraldehyde (GLU) is mainly used in medicine by healthcare workers during infection control as a chemical disinfectant. It has been linked to numerous health hazards that range from asthma to irritation of the eye to contact dermatitis. Citrullus colocynthis (C.C.) is utilized as a supplement to combat a range of health-related problems. This study aimed to assess the effectiveness of locally applied Citrullus colocynthis extract and Citrullus colocynthis loaded with ZnONPs against dermatitis caused by the disinfectant glutaraldehyde (2%).The female mice were divided into five groups (G1, G2, G3, G4, and G5). Group 1 was used as a control. The other 4 groups (2,3,4,and 5) were sprayed with 2% GLU (2 mg/kg body weight), and the other groups (3,4,and 5) were subjected to local application of natural products (Citrullus colocynthis extract cream, ZnONP cream, and Citrullus colocynthis loaded on ZnONP cream), respectively. Each experimental animal was followed for 5 days per week for 30 days.Our findings revealed that GLU-induced dermatitis via the upregulation of TNF-α, IL-1b, NFkb 1, and ptgs2 mRNA expression and the downregulation of TGFB1 mRNA expression caused oxidative stress and altered the biochemical markers and histological appearance. However, these effects were improved by the ZnONPs, C.C. extract, and C.C.-ZnONPs.Local application of Citrullus colocynthis ZnONPs and ZnONPs had preventive effects against GLU-induced dermatitis through the suppression of oxidative stress and inflammatory markers and the enhancement of antioxidants.

The influence of different crosslinking agents onto the physical properties, integration behavior and immune response of collagen-based barrier membranes.

This study investigates the mechanical properties as well as in vitro and in vivo cyto- and biocompatibility of collagen membranes cross-linked with glutaraldehyde (GA), proanthocyanidins (PC), hexamethylendiisocyanate (HMDI) and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EC/NHS). A non-crosslinked membrane was used as reference control (RF). The initial in vitro cytotoxic analyses revealed that the PC, EC, and HMDI crosslinked membranes were cytocompatible, while the GA crosslinked membrane was cytotoxic and thus selected as positive control in the further in vivo study. Cross-linking enhances the tensile strength and collagenase resistance, effectively prolonging the membrane's standing time in vivo. Using (immune-) histochemistry and histomorphometrical analyses, the cellular inflammatory responses, tissue integration and vascularization patterns at 10-, 30-, and 90-day post-implantation in a subcutaneous implantation model in rats were analyzed. The PC membrane elicited the mildest inflammatory cell levels, akin to the RF membrane, while other groups induced an M1-dominated macrophage response and numerous multinucleated giant cells throughout the study period. EC membranes maintained structural stability up to 30days post-implantation, similar to the GA group, whereas others collapsed prematurely. Concurrent with membrane collapse, transmembrane vascularization occurred across all groups. Histopathological and histomorphometry results reveal the intricate interplay of inflammatory cell populations in vascularization. These findings offer valuable insights into the pivotal role of cross-linkers in modulating mechanical properties and tissue responses of collagen membranes.

Regeneration of the skin wound by two different crosslinkers: In vitro and in vivo studies.

For designing a suitable hydrogel, two crosslinked Alginate/ Carboxymethyl cellulose (Alg/CMC) hydrogel, using calcium chloride (Ca2+) and glutaraldehyde (GA) as crosslinking agents were synthesized and compared. All samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Blood compatibility (BC), Blood clotting index (BCI), weight loss (WL), water absorption (WA), pH, and Electrochemical Impedance Spectroscopy (EIS). Cell viability and cell migration were investigated using the MTT assay and the wound scratch test, respectively. Besides, the wound healing potential of prepared hydrogels was evaluated on the rat models with full-thickness skin excision. To further investigation, TGF β1, IGF-I, COL1, ACT-A (alfa-SMA), and GAPDH expression levels were also reported by RT-PCR. Water absorption and weight loss properties were compared between different crosslinker agents, and the most nontoxic crosslinker concentration was determined. We have shown that GA (20 µl/ml) and Ca2+ (50 or 75 mM) enhanced the physical stability of Alg-CMC hydrogel, and they are nontoxic and suitable crosslinkers for wound dressing applications. Although in vivo assessments indicated that the GA (20 µl/ml) had a cytotoxic effect on tissue repair, Ca2+ (75 mM) boosted the wound healing process. Further, RT-PCR results revealed that TGF β1, IGF-I, COL1, ACT-A (alfa-SMA), and GAPDH expression levels were increased in GA (20 µl/ml). Moreover, this trend is the opposite in the Ca2+ (75 mM) treatment groups. This research shows that Ca2+ (75 mM) boosts tissue regeneration and wound healing process.

Evaluation of cross-linkers in the design of immobilized multi isomerase cascade for the preparation of rare sugars.

The cascade of sugar isomerases is one of the most practical methods for producing rare sugars, and enzyme immobilization endows it with high economic efficiency, operational convenience and reusability. However, the most employed cross-linker glutaraldehyde (GA) has the disadvantages of enzyme deactivation and limitation of substrate binding. Herein, three compounds, glyoxal, GA, and 2,5-furandicarboxaldehyde (DFF) were evaluated within a previously developed cascade comprising ribose-5-phosphate isomerase and D-tagatose-3-epimerase to prepare D-ribulose form D-xylose. Analyses of surface morphology, element and chemical bond revealed that all compounds effectively cross-linked the isomerases. High concentration of the cross-linkers was generally beneficial for binding protein and preventing enzyme leak during reusing cycles. Glyoxal performed the highest immobilization rate, though it hadn't been employed as a cross-linker for enzyme immobilization. DFF mediated cross-linking revealed the highest activity recovery, substrate conversion and residual activity after reusing cycles, suggesting better biocompatibility than glyoxal and GA. After 8 rounds of recycling, the residual activity of enzyme immobilized by DFF was 61.4 %, ~30 % higher than that of GA. This study proved a potential alternative cross-linker DFF for the immobilization of enzyme cascade with high activity recovery and reusability, which could promote the efficient production of high value-added products from biomass monosaccharides.

Sodium tripolyphosphate is a non-toxic and economic alternative to glutaraldehyde for preparation of L-asparaginase CLEAs to reduce acrylamide in potato fries.

L-Asparaginase CLEAs were prepared utilizing sodium tripolyphosphate (TPP) as a crosslinker (TA-CLEA). Under optimized conditions (pH 3, 0.3% TPP concentration, and a crosslinking time of 1 h), an 85% activity recovery was achieved. TA-CLEAs demonstrated superior pH stability (pH 3-8) compared to GA (glutaraldehyde)-CLEA but lost structural integrity at pH 9. TA-CLEAs were thermally more stable (concerning activity) and structurally less stable than GA-CLEA owing to the presence of weaker ionic bonds. TA-CLEAs reported an increase in apparent Km (reduced substrate affinity) and apparent Vmax values and displayed excellent reusability after 10 cycles of use (> 75%). The increase in β-sheet and random coil structures indicated a trade-off between structure stability and flexibility of the protein. TA-CLEAs reduced the acrylamide content in potato fries by 79% after 40 min of treatment time. Thus, the use of TPP as a non-toxic, economical, and biocompatible alternative to the conventionally used toxic crosslinker glutaraldehyde was demonstrated.

A novel polymer composite from polyhexamethylene guanidine hydrochloride for high performance triboelectric nanogenerators (TENGs).

In this study, we report the successful fabrication of a novel antibacterial triboelectric nanogenerator (TENG) using a polymer composite film based on polyhexamethylene guanidine hydrochloride (PHMG). The composite materials, with optimised ingredient ratios, consist of PHMG, polyvinyl alcohol (PVA) and glutaraldehyde (GA) as a crosslinking agent (PHMG-GA-PVA). Utilising 3D printing, these composite materials were directly deposited on the conductive substrates and used as positive TENG electrodes. The obtained results show that the TENGs based on PHMG-GA-PVA exhibit high output efficiency, achieving peak-to-peak open-circuit voltage (V p-p) and short-circuit current (I SC) values of 664.5 V and 116.8 μA, respectively, at a low operating frequency of 1 Hz with an actuation force of 10 N. The device retains approximately 98% of its initial output voltage value after 360 000 contact-release cycles.

Graphene nanocoating on titanium maintains structural and antibiofilm properties post-sterilization

ObjectiveTo evaluate the impact of sterilization methods on the structural integrity and antimicrobial properties of graphene nanocoating on titanium (GN). MethodsGN was transferred to titanium using wet (WT) or dry transfer (DT) techniques and sterilized using an autoclave (AC), glutaraldehyde (GA), or ethylene oxide (EtO). The GN structure was characterized using Raman spectroscopy before and after sterilization. Additional specimens were characterized by Raman after AC and water jetting. Biofilm formation was assessed before and after AC using colony-forming units (CFU), biofilm biomass, and SEM (uncoated titanium was the control). Three independent samples were used for structural characterization and biofilm quantification. Statistical analyses were conducted using one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). ResultsWT and DT demonstrated high structural stability after sterilization and water jetting, with negligible coating quality or coverage loss. GN exhibited lower biofilm formation even after AC sterilization, as shown by the reduction in CFU counts, biofilm biomass, and SEM images compared to the control. SignificanceGN demonstrated high resistance to the stresses imposed by all sterilization methods tested, maintaining its structural integrity, resistance to water-jet cleaning, and antibiofilm potential. The findings suggest that standard industrial practices can effectively sterilize highly resilient GN on titanium implants and possibly other biomaterials.

A novel chitosan microsphere as food processing enzyme immobilization carrier and its application in nucleotide production.

Developing a robust and safe carrier for enzyme immobilization is crucial for their application in the food processing industry. In this study, a novel crosslinked chitosan microspheres (CSMs) were prepared using glutaraldehyde (GA) as the crosslinking agent, using a newly developed emulsification-neutralization combined method. Nuclease P1 (NP1) was immobilized onto these microspheres, the maximum activity of NP1@CSMs-GA reach to 53,859.4U/g. The activity recovery yield reach to 75%. Compared to the free NP1, the stability of NP1@CSMs-GA was significantly enhanced. Its vmax and Km is 895.71mg/(g·min) and 77.27mg/mL respectively. This NP1@CSMs-GA was utilized in production of nucleotides through hydrolysis of RNA. In BSTR, NP1@CSMs-GA retained more than 75.1% initial activity after 10cycles of reuse. Moreover, in PBR, the RNA hydrolysis conversion rate maintained 81% after 24h of continuous operation. These results demonstrate that NP1@CSMs-GA exhibits excellent reusability and production stability in practical processes.

A Novel Crosslinking Approach for Biomanufacturing of a Collagen-Based Skin Dermal Template.

Third-degree burns result in extensive damage to the skin's epidermal and dermal layers, with limited treatment options available. Currently, xenogeneic collagen-based skin grafts are used as scaffolds to integrate into the wound bed and provide a template for neodermis formation. Existing commercial products like Integra dermal templates rely on a time-consuming and variable dehydrothermal (DHT) crosslinking process. This study presents a novel crosslinking process for collagen sponges, utilizing UV irradiation followed by glutaraldehyde (GA) crosslinking. This UV method allows to fine-tune the template's crosslink density and degradation profile while significantly reducing the total crosslinking time from 48 to 24 h compared to DHT/GA crosslinking. In vitro characterization and in vivo validation are conducted using a full-thickness skin wound mouse model. The collagen template supports the human dermal fibroblast cell line WS-1 proliferation more effectively than the Integra template after 2 weeks in culture. Additionally, in vivo data indicate a similar level of regeneration of full-thickness skin wounds in mouse models between the sponge and Integra templates. Furthermore, the sponge template does not elicit any abnormal angiogenic or immune responses. The crosslinking approach offers a promising alternative production process for collagen sponge scaffolds.

Preparation and Characterization of Poly(vinyl-alcohol)/Chitosan Polymer Blend Films Chemically Crosslinked with Glutaraldehyde: Mechanical and Thermal Investigations.

In this study, poly(vinyl-alcohol) (PVA)/chitosan (CS) polymer blend films with different amounts of CS (0, 5, 20 and 35 wt. %) crosslinked by glutaraldehyde (GA) were prepared. The structure and properties of the prepared polymer films were studied by means of dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and the time-lag permeation technique. The DMA analysis showed that CS reduces the crystallinity degree of PVA, leading to a higher amount of the amorphous phase contributing to the α relaxation that corresponds to the glass-to-rubber transition. However, the mobility of the amorphous phase can be restricted with crosslinking with 1 wt. % GA. Interaction between the PVA and the CS was confirmed by DCS analysis. Additionally, the influence of the CS and crosslinking on the permeation of nitrogen molecules was investigated. The permeation was examined by the time-lag method. It was found that the addition of CS and GA to PVA improves barrier properties.