Tripolyphosphate Research Articles

A Randomized Clinical Study Investigating the Stain Removal Efficacy of Two Experimental Dentifrices.

This study aims to evaluate extrinsic tooth stain removal and whitening efficacy of two experimental dentifrices containing (i) 5% sodium tripolyphosphate (STP)/1% micronized alumina or (ii) 5% STP/1% micronized alumina with abrasive silica (ED2) compared to a regular fluoride dentifrice (RFD) following 8 weeks of use. This was a single-center, randomized, controlled, blind, three-arm, stratified, parallel-group study. Eligible participants underwent clinical assessment of stain on the facial/lingual surfaces of maxillary and mandibular teeth using the modified Lobene stain index (MLSI), and shade of the facial surfaces of the central and lateral maxillary incisors using the VITA Bleachedguide 3D-Master (VITA) shade guide. Participants brushed twice daily with their assigned dentifrice and returned to the clinic for clinical assessments at weeks 4 and 8. A total of 272 participants completed the study (281 screened, 279 randomized). Both experimental dentifrices demonstrated statistically significant reduction from baseline and significant differences compared to RFD for MLSI and VITA shade scores at 4 and 8 weeks. 10 treatment-related treatment-emergent adverse events were reported in seven participants. All were resolved at the end of the study. This study demonstrated that dentifrices containing 5% STP/1% micronized alumina provide enhanced stain removal and shade improvements compared to a regular dentifrice. Study treatments were generally well tolerated. A low-abrasion daily-use fluoride dentifrice containing 1% micronized alumina and 5% STP, suitable for people at risk of erosive toothwear and/or dentin hypersensitivity, can provide clinically meaningful superior reductions in tooth stain, which translates into a visibly noticeable improvement in tooth shade.

Smart Zinc-Based Coatings with Chitosan–Alginate Nanocontainers Loaded with ZnO and Caffeine for Corrosion Protection of Mild Steel

The development of environmentally friendly materials is a subject of increasing interest in corrosion protection research. The objective of the present investigation is to propose the preparation procedure of chitosan–alginate (CHI/ALG) nanocontainers loaded with zinc oxide (ZnO) nanoparticles or combining ZnO nanoparticles with corrosion inhibitor caffeine (CAF), both suitable for incorporation into the matrix of ordinary zinc coatings on mild steel substrates. The nanocontainers were synthesized through spontaneous polysaccharide complexation in the presence of ZnO nanoparticles and CAF using a cross-linking agent, namely tripolyphosphate (TPP). Dynamic light scattering and laser Doppler velocimetry measurements are used for evaluation of the size distribution and zeta potentials of the nanocontainers, both loaded or unloaded with CAF. Using UV-spectroscopy, entrapment efficiency and release amounts of CAF are quantitatively evaluated. The nanocontainers thus obtained were incorporated into the matrices of ordinary zinc coatings via co-electrodeposition with zinc from zinc sulfate solution, aiming to improve the corrosion protection of steel in corrosive environments containing chloride ions. The surface morphology and elemental composition of the electrodeposited hybrid coatings before and after treating in the model corrosive medium of 3.5% NaCl is studied by scanning electron microscopy (SEM). The cyclic voltammetry method (CVA) is applied to characterize the cathodic (electrodeposition) and anodic (dissolution) processes. The protective characteristics of the hybrid coatings are investigated by application of potentiodynamic polarization (PDP) curves and polarization resistance (Rp) measurements after a time interval of 40 days. The obtained results indicate that both hybrid coating types could prolong the life time of mild steel in aggressive Cl− ion-containing solution, combining the protection effect of sacrificial zinc with barrier (ZnO) and active (CAF) protective effects.

Stabilization of calcium-fortified soy protein emulsions by calcium chelating agent sodium tripolyphosphate

Stabilization of calcium-fortified soy protein emulsions by calcium chelating agent sodium tripolyphosphate

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

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

Development of an Ocular Film Containing Ofloxacin in a Chitosan Matrix

Background: Chitosan is a natural polymer that is widely used in pharmaceutical applications owing to its biodegradability and biocompatibility. High molecular weight chitosan, which is commonly found in the market (Sigma Aldrich), is acid soluble and thus limits its application for ocular purposes. Objective: This study aimed to improve the characteristics of high-MW chitosan ocular films by utilizing a water-soluble, low-MW chitosan modifier for the delivery of ofloxacin post-surgery. Methods: Various film formulas were prepared using high-MW chitosan as the main polymer matrix, glycerin and polyethylene glycol 400 as plasticizers, and low-MW chitosan as film modifiers. Glycerine was the best plasticizer that produced a good film appearance when added at an appropriate ratio, 8.33 times the weight of the high MW chitosan (TGc) and 6.25 times the weight of low- and high-MW chitosan blends at (1:1) ratio (MGb). The films were further developed as TGcs and MGbs were cross-linked using sodium tripolyphosphate to control the release of ofloxacin and improve its mechanical characteristics. Water absorption capability, mechanical characteristics, in vitro drug release, and antimicrobial activity were evaluated to determine the film formula. Results: The MGb formula showed the highest water absorption (approximately 230 %), while the lowest was shown by the TGcs formula (approximately 145 %). In contrast, the TGcs formula had the highest film elasticity (141.33±8.81%), and the MGb formula had the lowest (42.55±6.11%). Surprisingly, the best controlled release of ofloxacin for up to 24 h was produced by the MGbs film, which also showed the highest antimicrobial activity. MGbs also showed moderate film characteristics, which are suitable for ocular applications. Conclusion: The research concluded that The addition of water-soluble low-MW chitosan and a cross-linker agent can improve the controlled release and characteristics of chitosan-based ocular films.

Application of cellulose nanofibers as cryoprotective in frozen storage of chicken surimi-like material.

The application of cellulose nanofibers (CNF) as cryoprotectants in frozen foods has rarely been explored. In this study, the cryoprotective effect of CNF (2, 4 and 6 % w/w) on mechanically separated chicken meat (MSCM) surimi-like material was investigated, during frozen storage (5 and 60 days) under temperature fluctuation. Surimi-like without cryopreservation agents was more susceptible to protein oxidation due to ice recrystallization. The addition of 2 % w/w CNF attenuated the oxidation of myofibrillar proteins to the same extent as adding commercial cryoprotectants (sucrose, sorbitol and sodium tripolyphosphate). The surimi-like material containing 2 % CNF exhibited a high concentration of salt-soluble proteins (9.6 ± 1.1 mg/g), lower protein carbonylation (1.9 ± 0.3 nmol/mg) and few changes in the secondary structure of the myofibrillar proteins. In addition, this treatment minimized the percentage of water loss by thawing and cooking (30.2 ± 2.2 %), generating gels with a high water holding capacity (86.8 ± 1.6 %) and microstructure that was more homogeneous and less porous compared to the control (without cryoprotectants) and other treatments containing CNF. The cryoprotective efficacy of CNF was evident in surimi-like material, being an alternative compound to commercial cryoprotectants.

Phosphate and two-stage cooking: Impact on lipid oxidation and tenderness in sous-vide beef semitendinosus.

The study investigated phosphate's effects on tenderness and lipid oxidation in beef cooked sous-vide. Semitendinosus beef cuts were treated with 0.15% and 0.3% sodium tripolyphosphate (STPP), and plain water (0% STPP). These cuts were then sous-vide cooked at two different temperatures, 60 °C and 70 °C, for two different durations, 3 h and 6 h. Analytical techniques including Warner-Bratzler shear force (WBSF), pH, thiobarbituric acid reactive substances (TBARS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed. STPP concentration did not yield a statistically significant impact on the pH and FTIR spectrum of sous-vide beef (p > 0.05). However, STPP markedly enhanced tenderness by loosening the myofibril structure (observed in SEM) and weakening myosin and actin bands (observed in SDS-PAGE). This improvement led to lower WBSF values with 0.3% STPP, particularly noticeable at 60 °C for 6 h. Additionally, 0.3% STPP delayed lipid oxidation, evidenced by lower oxidation values after 4 weeks of refrigerated storage at 4 °C. These findings highlight STPP's potential to improve tenderness and lipid oxidation stability in sous-vide beef.

Ultrasensitive Organic Photoelectrochemical Transistor Biosensor Based on DNA as Nanocarrier for Efficient Immobilization of Signal Probe with Pimping Background.

Organic photoelectrochemical transistor (OPECT) assays are mainly focused on the improvement of photoactive materials at the gating interface, which leads to an enhanced initial signal alongside significant background noise. This phenomenon can cause considerable deviations and impose limits on target detection. In this study, we achieved sensitive and low-background detection of alkaline phospholipase (ALP) activity using single-stranded DNA (ssDNA) as a nanocarrier to effectively immobilizing CdS quantum dots (QDs) sensitizing UiO-66. Specifically, ssDNA-labeled CdS QDs could be connected to UiO-66 via Zr-O-P bonds, while sodium tripolyphosphate (STPP) interfered with the binding of CdS QD-ssDNA to UiO-66 due to an occupancy effect. The hydrolysis of STPP, catalyzed by ALP, diminished this occupancy effect, allowing for increased binding of CdS QDs-ssDNA to UiO-66 and thereby enhancing the responsive signal. The competitive dynamic between STPP and ssDNA allowed for controlled binding of CdS QDs-ssDNA photosensitizers on UiO-66, thus realizing sensitive detection of ALP. This organic integration of biological modulation and signal amplification in OPECT has led to the creation of a novel sensing platform for detecting ALP concentrations ranging from 0.005 to 100 U·L-1, and the detection limit is 0.0012 U·L-1, thus paving the way for innovative approaches to sensitively monitor ALP activity.

Poly(allylamine)/tripolyphosphate nanocomplex coacervate as a NLRP3-dependent systemic adjuvant for vaccine development.

Nanotechnology plays a crucial role in vaccine development. It allows the design of functional nanoparticles (NPs) that can act both as antigen carriers and as adjuvants to enhance the immune response. The present study aims to evaluate complex coacervate-like NPs composed of poly(allylamine hydrochloride) (PAH) and tripolyphosphate (TPP) as a safe vehicle and adjuvant for systemic vaccines. We investigated the activation of different antigen-presenting cells (APCs) with NPs and their adjuvanticity in Balbc/c and different KO mice that were intraperitoneally immunized with NP-OVA. We found that NPs increased the expression of CD86 and MHCII and promoted the production and secretion of interleukin-1β (IL-1β) and IL-18 through the inflammasome NLRP3 when macrophages and dendritic cells were co-incubated with LPS and NPs. We evidenced an unconventional IL-1β release through the autophagosome pathway. The inhibition of autophagy with 3-methyladenine reduced the LPS/NPs-induced IL-1β secretion. Additionally, our findings showed that the systemic administration of mice with NP-OVA triggered a significant induction of serum OVA-specific IgG and IgG2a, an increased secretion of IFN-γ by spleen cells, and high frequencies of LT CD4 + IFN-γ + and LT CD8 + IFN-γ + . Our findings show that NPs promoted the inflammasome activation of innate cells with Th1-dependent adjuvant properties, making them valuable for formulating novel preventive or therapeutic vaccines for infectious and non-infectious diseases.

Ionic Crosslinking of Linear Polyethyleneimine Hydrogels with Tripolyphosphate.

In this work, the mechanical properties of hydrogels based on linear polyethyleneimine (PEI) chemically crosslinked with ethyleneglycoldiglycidyl ether (EGDE) were improved by the ionic crosslinking with sodium tripolyphosphate (TPP). To this end, the quaternization of the nitrogen atoms present in the PEI structure was conducted to render a network with a permanent positive charge to interact with the negative charges of TPP. The co-crosslinking process was studied by 1H high-resolution magic angle spinning (1H HRMAS) NMR and X-ray photoelectron spectroscopy (XPS) in combination with organic elemental analysis and inductively coupled plasma mass spectrometry (ICP-MS). In addition, the mobility and confinement of water molecules within the co-crosslinked hydrogels were studied by low-field 1H NMR. The addition of small amounts of TPP, 0.03 to 0.26 mmoles of TPP per gram of material, to the PEI-EGDE hydrogel resulted in an increase in the deformation resistance from 320 to 1080%, respectively. Moreover, the adsorption capacity of the hydrogels towards various emerging contaminants remained high after the TPP crosslinking, with maximum loading capacities (qmax) of 77, 512, and 55 mg g-1 at pH = 4 for penicillin V (antibiotic), methyl orange (azo-dye) and copper(II) ions (metal ion), respectively. A significant decrease in the adsorption capacity was observed at pH = 7 or 10, with qmax of 356 or 64 and 23 or 0.8 mg g-1 for methyl orange and penicillin V, respectively.

Structural features, physiological functions and digestive properties of phosphorylated corn starch: A comparative study of four phosphorylating agents and two preparation methods.

Phosphorylation is an important modification to modulate functional and digestive properties of starches. We systematically investigated starch phosphorylation process parameters by using two different preparation methods (slurry and semi-dry conditions) and four commonly used phosphorylating agents, namely sodium tripolyphosphate (STPP), sodium trimetaphosphate (STMP), STMP/STPP (99: 1), and sodium phytate (SP). The effects of phosphorylation on physicochemical characteristics, techno-functionalities, digestive properties and structural features of corn starch were analyzed. Phosphorylation with the semi-dry method resulted in higher phosphorus content, degree of double helix, and degree of starch aggregation and lower amylose content and relative crystallinity than with the slurry method. Phosphorylation using semi-dry conditions, irrespective of the used phosphorylating agent, furthermore decreased the gelatinization temperature, enthalpy, the temperature corresponding to the maximum starch mass loss rate and estimated glycemic index of corn starch, and increased solubility, swelling power, peak viscosity, transmittance, and resistant starch content. Of the phosphorylating agents, independent of the used preparation method, STMP and STMP/STPP resulted in the highest degrees of starch phosphorylation and therefore modulated the physiochemical, functional and digestive properties of corn starch more than STPP and SP. The findings of this systematic comparison provide important information to tailor phosphorylated corn starches to meet specific food requirements.

Effect of reactive extrusion processing conditions on the production of potato-resistant starch and its use as an additive in yogurt.

Starch has multiple uses in the food industry as a stabilizer, adhesive, gelling agent, thickener, and water retention agent. Nonetheless, native starch presents limitations that restrict its applications. Thus, starch can be chemically modified by reactive extrusion (REX) to overcome these disadvantages. Additionally, resistant starch (RS) can be obtained by REX and used as an additive to improve the nutritional quality and physicochemical properties of foods. Hence, this research aimed to determine the optimal processing conditions of REX to obtain RS with an adequate degree of substitution (DS) for use as an additive in yogurt. Potato starch was modified with sodium trimetaphosphate and sodium tripolyphosphate. The effects of extrusion temperature (ET=90.00-160.00°C) and moisture content (MC=18.00-30.00%) on the physicochemical properties (water absorption, solubility index, color, and DS) of extrusion-phosphated potato starch (EPPS) were studied. A single-screw laboratory extruder and a central composite rotatable design were employed. Natural yogurt was prepared with EPPS and conventionally phosphorylated starch, and their physicochemical and sensory properties were evaluated. EPPS showed a higher percentage of RS, which can be attributed to mechanical damage and loss of crystallinity due to REX and the formation of phosphodiester bonds and cross-linking. The optimization analysis identified the best processing conditions (107.40°C ET and 30.00% MC) to obtain EPPS with high RS and WAI values and a DS=0.02. This study demonstrated that ET and MC during REX are crucial for obtaining starch with a high percentage of RS. Adding RS obtained through REX improved the yogurt's physicochemical properties and enhanced its sensory characteristics.

Modulating the tumor microenvironment in a mouse model of colon cancer using a combination of HIF-1α inhibitors and Toll-Like Receptor 7 agonists.

The immunosuppressive tumor microenvironment (TME) plays a pivotal role in the response to various anticancer therapies, such as immune and chemotherapeutic agents. In this study, the synergistic effects of gene-targeting HIF-1α siRNA combined with Toll-Like Receptor 7 agonist on TME remodeling were investigated in a mouse model of colorectal cancer (CRC). A HIF-1α-specific siRNA duplex was formulated based on the ionic gelation of tripolyphosphate (TPP) with cationic chitosan (CH) as a nanoplex and evaluated in terms of size, charge, polydispersity index and gel retardation assay. MTT assay was conducted to assess the cytotoxicity of the specific siRNA duplex against CT26 cells. Hypoxic condition was generated to evaluate the gene and protein expression levels of HIF-1α, respectively. CT26 mouse model was established to assess the synergistic effect of silencing HIF-1α combined with oxaliplatin (OXA) and imiquimod (IMQ) on tumor growth. The mean diameter of the CH/siRNA nanoparticles was 243 ± 6 nm, as confirmed with Micrograph scanning electron microscope. There were no significant differences observed between the CT26 cells treated with nanoparticles alone and the untreated cells, indicating that these nanoparticles are safe and physiologically biocompatible (p ≥ 0.05). Triple combination therapy involving HIF-1α siRNA, OXA, and IMQ significantly retarded tumor growth and led to elevated levels of cytokines linked to cellular immunity (INF-γ and IL-12) compared with those in the other groups (P < 0.05). The positive correlation coefficient (r = 0.68) between tumor size and HIF-1α expression levels was statistically significant (P = 0.003). Compared with those in the control group, the expression levels of the anti-inflammatory cytokines IL-10 and IL-4 significantly decreased (P < 0.05). In conclusion, our findings suggest that inhibiting HIF-1α could serve as a rational strategy to enhance the antitumor response in the TME.

An intelligent chitosan/polyvinyl alcohol film with two types of anthocyanins for improved color recognition accuracy and monitoring fresh-cut pineapple freshness

In this study, chitosan (CS), polyvinyl alcohol (PVA), and sodium tripolyphosphate (STPP) were used as bases to introduce a blend of black wolfberry (BW) and red cabbage (RC) anthocyanins. The chelation reaction of CS, PVA, and STPP resulted in the composite anthocyanins being fixed within the matrix with an appropriate ratio of composite anthocyanins stably distributed in the film. The FTIR and X-ray analyses revealed that the addition of both types of anthocyanins strengthened hydrogen bond interactions. Moreover, the CP/BR-4 film exhibited excellent antioxidant, mechanical, and antibacterial properties, as well as a sensitive and rapid response to acidic substances. The freshness of pineapples stored under refrigeration for 6 d was also evaluated, showing more significant color changes with the CP/BR-4 film than the other treatment groups. Therefore, the composite anthocyanin film can potentially serve as an intelligent film for the detection of postharvest freshness in practical applications.

Tripolyphosphate-chitosan-pea protein interactions confers long-term stability to 3D printed high internal phase Pickering emulsions

This research explores the interactions of tripolyphosphate-chitosan-pea protein (TPP-CS-PP) in improving the stability and storage of 3D printing food inks. Chitosan (CS) and pea protein (PP) were complexed at various concentrations with 80 % palm olein to produce high internal phase Pickering emulsions (HIPPEs) 3D printing food inks. The resulting CSPP HIPPEs exhibited shear-thinning behaviour and the flexibility to switch between solid and liquid states, ideal for 3D printing. CSPP1:150 achieved the best 3D printing resolution and shape fidelity due to electrostatic attraction of CS-PP and excess PP enhancing adhesion at the oil/water interface. After spraying tripolyphosphate (TPP), crosslinking with CS and phosphorylation of PP further improved HIPPE resistance to deformation and oiling off for 2 days post-printing. This is a significant improvement over the control. Thus, further investigation on the interaction of TPP with CS and PP is warranted to further improve the storage stability of 3D printed food inks.

Fibrous phosphosilicate with highly dispersed poly(ionic liquids) as a nanocatalyst for production of biopolymer from limonene epoxide and CO2

In this study, we developed nano accelerators with a broad range by utilizing the interaction between tetraethyl orthosilicate (TEOS) and tripolyphosphate (TPP), followed by attaching poly(ionic liquids) to the click-modified ligand of fibrous phosphosilicate (FPS). This process led to the uniform distribution of poly(ionic liquids) without any aggregation, forming PILs-FPS. This material was then applied as a green catalyst for producing cyclic carbonate from limonene epoxide and CO2 under eco-friendly conditions. Subsequently, we synthesized a polymer from the natural cyclic carbonate obtained. The reaction between CO2 and highly substituted epoxides from sustainable sources like waste limonene produced novel bio-based cyclic carbonates. The reaction took place under mild, solvent-free conditions using PILs-FPS as the catalyst. The fibrous FPS structures enhanced adsorption capacity and facilitated the recovery of the catalyst without significant loss of activity. The products were easily separated from the environmentally conscious setting, and the catalyst was reused multiple times without a notable decrease in performance or selectivity.

The improved gel properties of myofibrillar protein under low salt condition by ultrasound-assisted sodium tripolyphosphate

Excessive salt intake is associated with increased risks of cardiovascular disease, while directly reducing salt content significantly decreased the quality of meat. The objective of this study was to investigate the synergistic effects of sodium tripolyphosphate (STP) and ultrasound treatment on the gel properties of MP under low-salt conditions (0.3 M NaCl). The results of FTIR spectra showed that P3O105− group of STP bound to -NH2 or -OH group of MP form C-N-P or C-O-P bond, indicating the STP was successfully introduced to MP. The addition of STP significantly increased the absolute value of Zeta-potential, suggesting that the presence of STP increased the electrostatic interaction of MP-MP. Importantly, STP combined with ultrasound treatment under low salt condition (STP-U0.3) significantly increased solubility and decreased particle size of MP. Besides, STP-U0.3 treatment also promoted the exposure of hydrophobic groups and improved the rheological behavior of MP, resulting in the highest gel strength (37.78 ± 0.71 g) and the lowest cooking loss (26.73 ± 0.90 %) especially in 10 mM STP combined 100 W ultrasound treatment. These results corresponded by the gradually increases of α-helix content and the decrease of tryptophan fluorescence intensity. Furthermore, results of SEM illustrated that STP-U0.3 treatment contributed to formation of more homogeneous and dense gel network of MP gel. The above results displayed that the STP-U treatment under 0.3 M NaCl resulted in an equivalent effect to control group of 0.6 M NaCl, indicating that the combined application of STP and ultrasound has a promising potential in the low-salt meat processing industry.

Remineralisation of mineral-deficient dentine induced by experimental ion-releasing materials in combination with a biomimetic dual-analogue primer

ObjectivesEvaluate the remineralisation ability of experimental resin-based materials containing Fluoride-Doped Calcium Phosphate (FDCP), applied in mineral-deficient dentine in combination with a biomimetic dual-analogue primer. MethodsArtificial dentine carious lesions were created in occlusal cavities of human molars. An experimental resin-based adhesive and flowable composite, containing FDCP (10wt% and 20wt%, respectively), were applied (±) with a biomimetic primer containing polyacrylic acid and sodium tripolyphosphate. A glass-ionomer cement and a conventional adhesive/composite were used as comparative materials. All specimens were submitted to chewing simulation in artificial saliva (AS). Subsequently, these were cut into slabs and submitted to Knoop microhardness testing and Raman spectroscopy (AS: 0, 15, 30 and 60 days). Further specimens were analysed through confocal scanning microscopy (AS: 0, 60 days). Total demineralised dentine and disc-shape materials were analysed through FTIR, SEM and EDX (Ca/P ratio) after prolonged contact in AS. Data were statistically analysed (two-way ANOVA and multiple comparison Bonferroni; α=0.05). ResultsOnly the experimental FDCP materials induced a significant increase in microhardness after storage in AS, especially in those specimens pre-treated with the biomimetic primer, except at 50 µm underneath the interface. Raman and CLSM analysis corroborated such results. The ability of the experimental FDCP resin-based materials to induce apatite-like deposition was demonstrated through SEM-EDX and FTIR. ConclusionsResin-based materials containing FDCP can mineralise the mineral-deficient dentine, especially when combined with a biomimetic dual-analogue primer. Clinical SignificanceSuch Innovative ion-releasing restorative systems applied after selective caries removal might promote remineralisation of fully and partially demineralised dentine and increase the durability of dental restorations.

Improving the catalytic activity and stability of Bacillus alcalophilus serine protease BAPB92 by rational design

The catalytic activity and stability of proteases are essential for their application in the detergent industry. To enhance the catalytic properties of BAPB92, homologous sequence comparison combined with rational design was employed. Six mutants were generated: BAPB92 (A188P), BAPB92 (V262I), BAPB92 (Q239R), BAPB92 (A188P/V262I), BAPB92 (Q239R/V262I), and BAPB92 (Q239R/A188P). Remarkably, the mutant BAPB92 (A188P/V262I) exhibited the most significant improvement, exhibiting a 4.30-fold increase in kcat/Km compared to the wild type, and a 0.75-fold enhancement in thermal stability at 60 °C. The enzymatic activity of BAPB92 (A188P/V262I) reached 6511.81 U/mg, which was 2.95 times higher than that of the wild type BAPB92. Furthermore, the optimal reaction temperature of this mutant increased from 50 °C to 60 °C. The BAPB92 (A188P/V262I) mutant also showed a marked improvement in detergent stability. In sodium tripolyphosphate liquid detergent, its washing efficacy was 17.84 % higher than that of the wild type, and in methyl glycine diacetate liquid detergent, the improvement was 18.51 %. These findings suggested that BAPB92 (A188P/V262I) holds significant potential as a detergent protease in the washing industry. Structural analysis and molecular dynamics simulations further confirmed the enhanced stability of this mutant compared to the wild type. This study provides valuable theoretical insights for the application of the serine protease BAPB92 in detergent formulations.

Synthesis of chitosan nanoparticles (CSNP): effect of CH-CH-TPP ratio on size and stability of NPs.

In the face of a pressing global issue-the escalating threat of antibiotic resistance-the development of new antimicrobial agents is urgent. Nanotechnology, with its innovative approach, emerges as a promising solution to enhance the efficacy of these agents and combat the challenge of microbial resistance. Chitosan nanoparticles (CSNPs) stand out in biomedical applications, particularly in the controlled release of antibiotics, with their unique properties such as biocompatibility, stability, biodegradability, non-toxicity, and simple synthesis processes suitable for sensitive molecules. This study synthesized CSNPs using the ionotropic gelation method, with tripolyphosphate (TPP) as the crosslinking agent. Various CS: TPP ratios (6:1, 5:1, 4:1, 3:1, 2:1) were tested, and the resulting nanoparticles were evaluated using dynamic light scattering (DLS). The CS: TPP ratio of 4:1, with an average hydrodynamic diameter (DHP) of (195 ± 10) nm and a zeta potential of (51 ± 1) mV, was identified as the most suitable for further analysis. The characterization of NPs by Transmission Electron Microscope (TEM) and atomic force microscopy (AFM) revealed diameters of (65 ± 14) nm and (102 ± 18) nm, respectively. Notably, CSNPs exhibited significant aggregation during centrifugation and lyophilization, leading to diameter increases of up to 285% as measured by AFM. The antibacterial activity of CSNPs against Staphylococcus aureus and Escherichia coli was assessed using the resazurin assay. It was found that CSNPs not subjected to centrifugation, freezing, and lyophilization retained their antimicrobial activity. In contrast, those that underwent these processes lost their efficacy, likely due to aggregation and destabilization of the system. This study presents a straightforward and effective protocol for encapsulating sensitive active agents and synthesizing chitosan nanoparticles, a potential system with significant implications in the fight against antibiotic resistance.