Thiol Groups Research Articles

Chiral microporous organic network/covalent organic framework/silica composites: Powerful and versatile chromatographic separation materials

Nowadays, covalent organic framework (COF) has shown great potential in chromatographic separation, and enriching the design of novel COF based stationary phases and broadening their application prospects remains of great significance. Microporous organic network (MON) is a novel type of porous material with large specific surface area and excellent stability connected by covalent bonding, which is extremely similar to COF. Especially, nano-sized MON has the characteristics of easy binding with silica matrix and superior chromatographic separation performance. In this work, the combination of MON and COF as the surface modification materials of silica gel was first explored. The conjugated network structure of MON and COF can improve the permeability of silica stationary phase, and the presence of abundant functional groups in COF and MON can enhance the separation ability for a series of aromatic compounds. Moreover, hydrophilic L-cysteine containing thiol group was cleverly introduced into MON/COF@SiO2via thiol-ene/yne click reactions to balance the hydrophilicity and hydrophobicity of stationary phase. The L-cysteine modified chiral MON/COF@SiO2 (CMON/CCOF@SiO2) was used for effective separation of various chiral/hydrophilic/hydrophobic analytes, and the CMON/CCOF@SiO2 was observed to exhibit superior separation ability to the CCOF@SiO2. Multi-mode chromatographic separation mechanisms were explored, demonstrating that multiple interactions were involved in the separation process. Finally, the CMON/CCOF@SiO2 was applied to detect the environmental endocrine disruptors in the water sample and pyridoxine in the tablet sample, respectively, indicating a great potential for application in actual sample detection.

Reactive Oxygen Species Triggered Cleavage of Thioketal‐Containing Supramolecular Nanoparticles for Inflammation‐Targeted Oral Therapy in Ulcerative Colitis

AbstractCombating reactive oxygen species (ROS) and targeted drug delivery to inflammatory sites are considered effective therapeutic strategies for ulcerative colitis (UC), a refractory chronic inflammatory disease. Herein, a ROS‐responsive thioketal (TK) crosslinked cyclodextrin metal‐organic framework (TCOF) is fabricated, to which a non‐ROS‐sensitive vector, sulfur substituted by carbon chain‐crosslinked cyclodextrin metal‐organic framework (CCOF) is parallelly designed as ROS negative reference. Dexamethasone (DEX) loaded in TCOF (TCD) and CCOF (CCD) are investigated to demonstrate the advantages of precision medicine for UC. After the ROS‐induced collapse of nanoparticles, TCD selectively triggered the release of DEX. Moreover, TCD effectively protected cells from oxidative stress damage and reduced inflammation levels in vitro. Remarkably, the TK group of TCD is oxidatively broken by consuming ROS at the inflammatory site, exposing the thiol group to mucosal adhesion, which enhances the retention of TCD at colons. In vivo studies of UC treatment reveals that oral administration of TCD demonstrated excellent inflammation‐targeting properties, remarkably attenuated oxidative stress, and ameliorated both acute and chronic colitis compared to CCD. Furthermore, TCD exhibits an excellent safety profile in mice. These results instill confidence in advancing targeted drug delivery and precision therapy for UC.

Development of a sensor to detect methylmercury toxicity

Methylmercury (MeHg) is a well-known neurotoxicant that induces various cellular functions depending on cellular- and developmental-specific vulnerabilities. MeHg has a high affinity for selenol and thiol groups, thus impairing the antioxidant system. Such affinity characteristics of MeHg led us to develop sensor vectors to assess MeHg toxicity. In this study, MeHg-mediated defects in selenocysteine (Sec) incorporation were demonstrated using thioredoxin reductase 1 cDNA fused with the hemagglutinin tag sequence at the C-terminus. Taking advantage of such MeHg-mediated defects in Sec incorporation, a cDNA encoding luciferase with a Sec substituted for cysteine-491 was constructed. This construct showed MeHg-induced decreases in signaling in a dose-dependent manner. To directly detect truncated luciferase under MeHg exposure, we further constructed a new sensor vector fused with a target for proteasomal degradation. However, this construct was inadequate because of the low rate of Sec insertion, even in the absence of MeHg. Finally, a Krab transcriptional suppressor fused with Sec was constructed and assessed to demonstrate MeHg-dependent increases in signal intensity. We confirmed that the vector responded specifically and in a dose-dependent manner to MeHg in cultured cerebellar granule cells. This vector is expected to allow monitoring of MeHg-specific toxicity via spatial and temporal imaging.

Effects of High-Pressure Homogenization on the Structure and Functional Properties of Solenaia oleivora Proteins.

Solenaia oleivora, a rare freshwater shellfish with high protein quality, is unique to China. However, the poor hydrosolubility and functional properties of Solenaia oleivora proteins hinder their utilization in food products. Herein, the alkaline dissolution-isoelectric precipitation method was used for the extraction of Solenaia oleivora proteins. Furthermore, the impact of high-pressure homogenization (HPH) treatment varying from 0 to 100 MPa on the structure and functional properties of Solenaia oleivora proteins was investigated. The obtained results indicated that HPH treatment decreased the α-helix content and enhanced the β-sheet and random coil content. Furthermore, the HPH caused the unfolding of protein structure, exposing aromatic amino acids, increasing the free thiol group content, and enhancing surface hydrophobicity. As the homogenization pressure increased from 0 to 100 MPa, the particle size of Solenaia oleivora proteins decreased from 899 to 197 nm with the polymer dispersity index (PDI) value decreased from 0.418 to 0.151, the ζ-potential increased from -22.82 to -43.26 mV, and the solubility increased from 9.54% to 89.96%. Owing to the significant changes in protein structure and solubility, the emulsifying, foaming, and digestive properties of Solenaia oleivora proteins have been significantly improved after treatment with HPH.

Modulating the spirolactone−zwitterion equilibrium of dichlororhodamine via changing its aqueous solubility: A new strategy to construct glutathione fluorogenic probe for bioimaging

The aqueous solubility is one of the key physical properties of a fluorophore. Herein, we synthesized and evaluated a series of 4,5-dichlororhodamine 19 (DCR) derivatives and demonstrated that the spirolactone-zwitterion equilibrium of DCR scaffold is highly dependent on its aqueous solubility: poor water-soluble DCR derivatives predominately adopt as a colorless, non-fluorescent spirolactone in neutral aqueous solution, whereas good water-soluble ones favor a colored, fluorescent zwitterion. To confirm the validity of this strategy, a hydrophobic benzyl thioester functionality was introduced to DCR platform to develop DCR-BTE as a fluorescent probe for glutathione (GSH). The transthioesterification between DCR-BTE and the thiol group of GSH affords a new thioester containing a good water-soluble GSH residue (DCR-GSH), thus shifting the equilibrium toward the fluorescent open form. DCR-BTE was proved to be capable of reporting the variations of GSH levels within the physiological concentration range, and its potential biological utility was shown by monitoring the depletion of GSH in the liver and kidney tissues of mice administrated by an overdose of acetaminophen. The present study provides an appealing strategy to construct fluorogenic probes based on tuning the lactone-zwitterion equilibrium of rhodamine via changing its aqueous solubility.

Mucoadhesive and drug release of cholic acid based thiomeric micelles and encapsulated silver and gold nanoparticles for anticancer studies

Among the various drug delivery system, mucoadhesive formulation is a promising approach to deliver drugs and vaccine through close contact with the absorption site and mucous membrane. Bile acids have received considerable interest in drug delivery (DD) applications owing to their advantages of biocompatibility, ability to act as both drug solubilizing and permeation-modifying agents. In this aspects, cholic acid (CA) based thiomeric micelles with improved mucoadhesive properties have been synthesized by functionalization of thiol groups and conjugation of PEG. The synthesized CA based thiomeric micelles (TCA-PEG) were characterized by 1HNMR, ATR-IR, GPC, Zeta potential and contact angle techniques. The critical micelle concentration (CMC) of TCA-PEG was measured by a fluorescence spectrometer using pyrene as a probe. The mucoadhesive properties of TCA-PEG polymeric micelles (PMs) were examined on the goat anterior tongue mucosa with an effectively higher adhesion of 40 % up to 3 h study period. Also, curcumin loaded TCA-PEG PMs showed only 13 % of the drug released up to the period of 3 h. The TCA-PEG PMs act as reducing and stabilizing agents for the preparation of gold and silver nanoparticle (Ag and Au NPs) and were characterized by UV–visible, DLS, Zeta potential, XPS, and HR-TEM techniques. The cytotoxicity and cellular apoptosis of TCA-PEG PMs encapsulated Ag and Au NPs were examined by MTT assay and AO/PI dual staining using MCF-7 breast cancer cells wherein AgNPs showed an effective cytotoxicity than AuNPs. The developed TCA-PEG PMs act as reservoir for soubilization of hydrophobic and hydrophilic drugs and ideal template for encapsulation of silver and gold nanoparticles for mucoadhesive DD system.

Pulmonary Protective Effects of Vitamin D and N-Acetylcysteine on Paraquat-Induced Lung Toxicity in Rats: Modulation of Oxidant / Antioxidant Balance

Background: Paraquat (PQ) is one of the most common herbicides used in agriculture that can lead to very acute toxicity in mammals. It has been reported that PQ has destructive effects on the lungs. Objective: We aimed to investigate the effect of N-acetyl Cysteine (NAC) and Vitamin D (Vit D) on the oxidative toxicity of the lung in subacute paraquat exposure. 36 male albino Wistar rats at 8 weeks were randomly divided into 6 groups (n=6). A control group, a PQ-intoxicated group (5 mg/kg body weight), a Vit D-treated group (2 μg/kg), an NAC-treated group, a PQ (6.25 mg/kg) + Vit D group, and finally a PQ + NAC group, each was treated for 7 days. Methods: In this experimental study, Lipid Peroxidation (LPO), Total Oxidant Status (TOS), Total Antioxidant Capacity (TAC), Total Thiol Groups (TTG), and Hydroxyproline (Hyp) levels in lung tissue were evaluated. Results: PQ exposure resulted in a substantial elevation of LPO, TOS, and Hyp levels. Conversely, TAC and TTG content demonstrably declined. Administration of either PQ+Vit D or PQ+NAC significantly reduced LPO, TOS, and Hyp levels in the PQ-exposed rats compared to the PQ group alone. Conversely, TAC and TTG content significantly increased in these groups. These findings suggest that both vitamin D and NAC may function as free radical scavengers and potential antioxidant agents, potentially alleviating the detrimental effects of PQ poisoning on the lungs. Conclusion: The present study has demonstrated the administration of Vit D and NAC to significantly mitigate PQ-induced lung injury in rats. This protective effect can be likely attributed to their modulation of the oxidant/antioxidant balance, as evidenced by reductions in LPO, TOS, and Hyp levels, alongside increases in TAC and TTG content. These findings suggest that vitamin D and NAC may function as free radical scavengers and antioxidant enhancers, offering protection against PQ-induced oxidative stress and subsequent lung tissue damage.

The Effects of Different Thiol-Containing Compounds on the Degradation of Sulforaphene.

Sulforaphene (4-methylsufinyl-3-butenyl isothiocyanate, SFE), produced by myrosinase hydrolysis of glucoraphenin (4-methylsulfinyl-3-butenyl glucosinolate) found in radish seeds, is strongly associated with cancer prevention. In this study, we investigated the stability of SFE (purity above 98%) under various thiol-containing compounds at 25 °C, such as sodium hydrosulfide (NaHS), glutathione (GSH), and cysteine (Cys). We observed that the degradation of SFE was closely related to the presence and dissociation capacity of thiol-containing compounds in the solution, particularly the thiol group. We found that the degradation rate of SFE was influenced by incubation with NaHS, GSH, and Cys, with distinct degradation products detected for each of these thiol-containing compounds. Compared to GSH, sulfide and Cys played important roles in promoting the degradation of SFE. Furthermore, we found substantial quantities of hydrogen sulfide in conjunction with SFE during the hydrolysis process of seeds, and a heat treatment of the seeds resulted in increased production of SFE. However, the introduction of sulfide-oxidizing bacteria to the hydrolytic system did not exhibit any inhibitory effect on the degradation of SFE. These results provided a guideline for industries to improve the stability of SFE during preparation.

Tailoring copolymer architectures and macromolecular interactions for enhanced nanotherapeutic delivery: A design-by-architecture approach

Amphiphilic copolymers with precise macromolecular topologies are crucial in nanomedicine for enhancing drug delivery by improving solubilization, stabilization, and therapeutic efficacy on target tissues. This study employs a design-by-architecture approach to identify factors influencing interactions between synthesized macromolecules and biological systems for optimal drug nanodelivery. Copolymers combining poly(ε-caprolactone) blocks and poly(polyethylene glycol methacrylate) or poly(glycerol methacrylate), were synthesized to investigate how architectural adjustments impact self-assembly, nanoparticle size, drug loading, and biomolecule interactions. Linear and brush block copolymers with varied block lengths were studied for their self-assembly behavior in aqueous environments. Both copolymer types formed smaller nanoparticles with extended hydrophilic blocks, with brush block copolymers showing superior performance due to their peculiar macromolecular architecture. Incorporating ‘clickable’ glycidyl units within the hydrophilic block minimally affected particle size. Controlled functionalization with thiol groups resulted in stable nanoparticles with enhanced size reduction and mucoadhesive properties, potentially improving targeted drug delivery and therapeutic effects.

Post-Translational Modifications to Cysteine Residues in Plant Proteins and Their Impact on the Regulation of Metabolism and Signal Transduction.

Cys is one of the least abundant amino acids in proteins. However, it is often highly conserved and is usually found in important structural and functional regions of proteins. Its unique chemical properties allow it to undergo several post-translational modifications, many of which are mediated by reactive oxygen, nitrogen, sulfur, or carbonyl species. Thus, in addition to their role in catalysis, protein stability, and metal binding, Cys residues are crucial for the redox regulation of metabolism and signal transduction. In this review, we discuss Cys post-translational modifications (PTMs) and their role in plant metabolism and signal transduction. These modifications include the oxidation of the thiol group (S-sulfenylation, S-sulfinylation and S-sulfonylation), the formation of disulfide bridges, S-glutathionylation, persulfidation, S-cyanylation S-nitrosation, S-carbonylation, S-acylation, prenylation, CoAlation, and the formation of thiohemiacetal. For each of these PTMs, we discuss the origin of the modifier, the mechanisms involved in PTM, and their reversibility. Examples of the involvement of Cys PTMs in the modulation of protein structure, function, stability, and localization are presented to highlight their importance in the regulation of plant metabolic and signaling pathways.

Comparative phytochemical, antioxidant, and hemostatic studies of fractions from raw and roasted sea buckthorn seeds in vitro

Various seeds, including sea buckthorn (Hippophae rhamnoides L.) seeds, are sources of different bioactive compounds. They can show anti-inflammatory, hypoglycemic, anti-hyperlipidemic, antibacterial, antioxidant, or other biological properties in in vitro and in vivo models. Our preliminary in vitro results have demonstrated that the extracts from raw (no thermal processing) and roasted (thermally processed) sea buckthorn seeds have antioxidant potential and anticoagulant activity. However, it was unclear which compounds were responsible for these properties. Therefore, in continuation of our previous study, the extracts were fractionated by C18 chromatography. Phytochemical analysis of three fractions (a, b, and c) from raw sea buckthorn seeds and four fractions (d, e, f, and g) from roasted sea buckthorn seeds were performed. Several in vitro assays were also conducted to determine the antioxidant and procoagulant/anticoagulant potential of the fractions and two of their major constituents—isorhamnetin 3-O-β-glucoside7-O-α-rhamnoside and serotonin. LC–MS analyses showed that serotonin is the dominant constituent of fractions c and f, which was tentatively identified on the basis of its HRMS and UV spectra. Moreover, fractions c and f, as well as b and e, contained different B-type proanthocyanidins. Fractions b and e consisted mainly of numerous glycosides of kaempferol, quercetin, and isorhamnetin. The results of oxidative stress assays (measurements of protein carbonylation, lipid peroxidation, and thiol groups oxidation) showed that out of all the tested fractions, fraction g (isolated from roasted seeds and containing mainly dihexoses, and serotonin) demonstrated the strongest antioxidant properties.

Deteriorated thiol-disulphide and oxidized-reduced glutathione status in blood in Alzheimer’s disease

BackgroundAlzheimer’s disease (AD) is a steadily advancing neurodegenerative condition, the occurrence and prevalence of which are on the rise in various populations. Suspected factors contributing to its development encompass the buildup of amyloid β (Aβ) plaques, the formation of neurofibrillary tangles induced by tau proteins, and heightened oxidative stress. In this study, we aimed to evaluate intra-cellular glutathione status and extracellular thiol-disulphide status in patients with AD. MethodsAdult patients (>60 years old) diagnosed with AD based on DSM-IV diagnostic criteria were included in the study. Patients were divided into 3 groups as mild, moderate and severe according to Mini Mental Status Examination (MMSE) and clinical findings. Extracellular thiol-disulfide and intracellular oxidized-reduced glutathione status parameters for patient and control groups were analyzed before and after reduction procedures by using reaction of thiol groups with DTNB. ResultsThe reduced forms of both balances (native thiol (NT) and reduced glutathione (GSH)) were significantly lower in the patient group than the control group (p = 0.031 and <0.001, respectively), while oxidized forms (disulphide (SS) and oxidized glutathione (GSSG)) and SS/NT and GSSG/GSH percent ratios were significantly higher (p < 0.05 for all). The disease duration and oxidative stress were significantly higher in the severe group of AD. There was a shift in intracellular and extracellular thiol balances towards the oxidized side, along with correlations between MMSE and these balances (rho = −0.412 for SS/NT and rho = −0.488 for GSSG/GSH), with GSSG/GSH identified as a significant predictive factor (odds ratio (95 % confidence interval): 1.352 (1.136–1.610) for the moderate group and 1.829 (1.451–2.305) for the severe group. ConclusionsThese findings suggest that blood redox balance is disrupted in AD.

Synthesis of SnC@Au@Apta by electrospinning as an electrochemical sensor for detection of tetracycline

A highly efficient electrochemical aptamer sensor for the detection of tetracycline (TC) was prepared by using SnC@Au@Apta. Metal tin has good electrochemical activity and high conductivity. It is often used as an electrochemical sensing material. The nanofibers prepared by electrospinning machine make the metal distribution more uniform, not easy to agglomerate, and have a certain porosity, which can improve the sensitivity of sensor detection. Carbonization further enhances conductivity. The gold nanoparticles (AuNPs) on the surface of SnC nanomaterials improve the electrochemical detection performance, and also act as the binding site of the TC aptamer, which is stably combined with the thiol group at the end of the TC aptamer. The TC aptamer specifically binds to TC to detect TC in the sample. The electrochemical performance of SnC@Au@Apta was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, the detection range of SnC@Au@Apta is wide (0.001–100 μM), the detection limit is low (0.83 nM), and it has excellent selectivity, stability and reproducibility. In addition, SnC@Au@Apta can be used to detect TC in milk samples.

Redox-Triggered Reversible Switching between Dynamic and Quasi-static α-Helical Peptides.

We report the reversible transformation between a singly stapled dynamic α-helical peptide and a doubly stapled quasi-static one through redox-triggered dithiol/disulfide conversions of a stapling moiety. This process allows the rate of interconversion between the right-handed (P) and left-handed (M) α-helices to be altered by a factor of approximately 103 before and after the transformation. An as-obtained doubly stapled α-helical peptide, which is composed of an achiral peptide having an l-valine carboxylic acid residue at the C-terminus, a disulfide-based reversible staple, and a biphenyl-based fixed staple, adopts an (M)-rich form as a kinetically trapped state. The (M)-rich helix was subsequently transformed into the thermodynamically stable (P)-rich form in 1,1,2,2-tetrachloroethane with the half-life time (t1/2) of approximately 44 days at 25 °C. Reduction of the doubly stapled peptide with tri-n-butylphosphine in tetrahydrofuran/water (10/1, v/v) produced the corresponding singly stapled dynamic α-helical peptide bearing two thiol groups at the side chains, which underwent solvent-induced reversible helicity inversion. The resulting dithiol of the singly stapled peptide could be reoxidized to form the original doubly stapled form using 4,4'-dithiodipyridine. Furthermore, the P/M interconversion of a doubly stapled peptide with two flexible hydrocarbon-based staples is considerably more rapid than that with more rigid staples.

Effect of ultrasound treatment on quality parameters and health promoting activity of fish protein hydrolysates extracted from side streams of Atlantic mackerel (Scomber scombrus).

Fish protein hydrolysates (FPH) obtained by enzymatic hydrolysis allows for smart valorization of fish side streams. However, further treatments are normally needed to enhance bioactive and functional properties of the obtained FPH. At present, the commonly used methods to improve functional properties of FPH include chemical and enzymatic modification. Chemical treatments often cause environmental problems, while the enzymatic modification method requires the use of quite expensive enzymes. In recent years, emerging technologies such as ultrasound treatment (US-treatment) have shown great potential in protein modification with high efficiency and safety, low energy consumption, and low nutritional destructiveness. In this study, high-power ultrasound treatments were applied to fish protein hydrolysates (FPH) extracted from Atlantic mackerel (Scomber scombrus) side streams to improve their quality parameters. The effect of three different treatments of 300 W, 450 W and 600 W at the operating frequency of 20 kHz for 10 min on the physicochemical, structural, and functional characteristics of FPH, were examined. The results have shown that with an increase in ultrasound power, the protein solubility of FPH increased linearly, and the changes were significant for all US-treated samples compared to control (untreated) samples. US-treatment significantly increased the degree of hydrolysis of FPH samples treated with 450 W and 600 W compared to control samples. The carbonyl content of FPH increased (significantly for 450 W and 600 W), while thiol groups decreased (significantly for 300 W and 450 W). This indicated that some US-treatments induced oxidation of FPH, however the values of the protein oxidation were low. Amino acid composition of FPH revealed that US-treatment increased the proportion of essential amino acids in the sample treated with 300 W and 450 W, but the increase was not significant. After the US-treatment, all FPH samples became lighter and less yellowish and reddish, which suggest potentially higher attractiveness to consumers. In addition, the in vitro antioxidant activity was assessed using the DPPH, FRAP, and ABTS assays and the cell-free dipeptidyl peptidase IV (DPP-IV) inhibitory activity was also measured. Moreover, these biological activities were measured at cellular level utilizing human intestinal Caco-2 cells. Specifically, the FPH capacity to lower H2O2-induced reactive oxygen species (ROS) and lipid peroxidation levels was used to measure its antioxidant activity. The findings suggest that Scomber scombrus hydrolysates could find use as ingredients for promoting health.

Tb3+-functionalized covalent organic framework for simultaneous detection and removal of Hg2+

Hg2+ is a common heavy metal ion contaminant in the environment, as well as one of the most hazardous metal ions on the earth, posing a serious threat to the ecosystem and human health. As a result, it is vital to develop materials that can detect or remove Hg2+. In this work, we fabricated a Tb3+-functionalized covalent organic framework (Tb@COF) platform capable of both detecting and removing Hg2+ for the fluorescence enhancement of Tb3+ and the presence of thiol groups in COF. Tb@COF exhibited good selectivity and sensitivity during the detection of Hg2+, with a linear range of 0.2–50 μmol/L(R2 = 0.9985) and a limit of detection (LOD) of 0.076 μmol/L. We employed Tb@COF to detect Hg2+ in lake water with excellent results, and we developed a smartphone-assisted Tb@COF-based agar slice detection platform that could identify Hg2+ both visually and quantitatively. We discussed the sensing mechanism of Tb@COF for Hg2+. Furthermore, we found that Tb@COF displayed good removal efficiency of Hg2+. The adsorption of Hg2+ by Tb@COF followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Our research provided a novel method for simultaneously detecting and eliminating Hg2+ from the environment.

Changes in the structural, aggregation behavior and gel properties of pork myofibrillar protein induced by theaflavins

This study explores the effect of different theaflavins (TFs) concentrations (0, 100, 300, 600 and 900 mg/L) on the structure, aggregation behavior and gelation properties of pork myofibrillar protein (MP). The protein structure and aggregation behavior were characterized by free sulfhydryl groups, surface hydrophobicity, fluorescence emission spectra, particle size and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The gel properties of samples were characterized by gel strength, cooking loss, microstructure and gel supernatant SDS-PAGE. The results showed a significant decrease in free thiol content with increasing TFs concentration, suggesting thiol-quinone covalent interaction between TFs and thiol group of MP. Intrinsic fluorescence spectroscopy confirmed a static quenching between TFs and MP. And TFs reduced the particle size of MP suspension and caused no protein aggregation bond in SDS-PAGE. For gel properties, TFs caused a decrease of gel strength from 96.77 g to 21.91 g and an increase in cooking loss from 40.34 % to 71.15 %. The bond of protein aggregates in gel supernatants SDS-PAGE revealed that some protein aggregates formed by disulfide bonding were not involve in gel formation with TFs addition. In conclusion, TFs cause thiol loss of MP and impaired MP gelling ability by interfering with disulfide bond formation during gelation.

A difunctional NMR&CD probe for specific detection and enantiomeric recognition of biothiols in complex mixtures

BackgroundBiothiols are important for numerous cellular processes, such as resisting oxidative stress and protecting cell health. Their abnormal levels and molecular configurations have been associated with various diseases. So, establishing an effective and reliable method for the specific detection and enantiomeric discrimination of diverse biothiols is highly meaningful. ResultsWe have developed a new NMR and CD probe using 1,4-dinitroimidazole, specifically targeting the thiol group. This probe allows for the specific detection and enantiomeric recognition of biothiols in complex mixtures. We achieved this by identifying the distinguishable 1H NMR signals of 2nd in imidazole-ring of the resulting 4NI-biothiols in the downfield region at 7–8 ppm and newly discovered induced CD signals within 290-430 nm. Using this probe, the limits of detection of Cys, GSH, and Hcy, the recovery rates, and the concentration of GSH extracted from HEK293T cells were determined by measuring the unique downfield 1H NMR signals. Moreover, Cys, GSH, and Hcy can be discriminated simultaneously in complicated samples at a pH range of 2–3.5. Furthermore, this probe can also be utilized to sense chiral thiol-drugs. SignificanceThis method offers a cost-effective and accurate sensing solution for the specific detection of biothiols in complex mixtures, with stereochemical recognition.

Ag-MOF Nanocatalyst for the Asymmetric Hantzsch Synthesis of Polyhydroquinolines Under Green Conditions

A highly efficient and stable heterogeneous coordination polymer (CP) catalyst was successfully prepared by hydrothermal reaction of silver and 4,6-Diamino-2-pyrimidinethiol, using amine, thiol and pyrimidine functional groups. Besides, silver ions were coordinated to the ligand functional groups in order to give a novel Ag-CPs catalyst. Besides, it was characterized using FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and BET analysis. The prepared Ag-CPs exhibit excellent catalytic activity for multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction condition in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test and, then, the catalyst was reused for at least four times under the optimized conditions without any significant loss of its activity.

Comprehensive study of plasma polymerization parameters on thiol-coated LDPE films for effective fibronectin adsorption targeting biomedical applications

In the realm of biomedical applications, biocompatible materials with optimized surface properties are crucial for facilitating cellular interactions. To attain the perfect balance of these properties, surface modification of non-toxic and stable bulk materials is often required. Within this context, this research aimed to improve the physiochemical and cell-responsive properties of a low-density polyethylene film. This was achieved by depositing thiol-rich coatings using a dielectric barrier discharge plasma reactor operating at medium pressures, with 1-propanethiol serving as polymerization precursor. The study systematically investigated the impact of key plasma polymerization parameters, including DBD chamber pressure, treatment time, and the combination of precursor flow rate and discharge power represented by the Yasuda parameter, to identify optimal plasma processing conditions for the formation of thiol-rich coatings. To characterize the coating thickness, hydrophilicity and surface chemical composition, atomic force microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy were employed. The findings indicated that reducing the chamber pressure to 10 kPa led to more hydrophilic and thicker deposits possessing a higher sulphur content. Deposition time (5 to 15 min) also significantly impacted coating thickness and surface chemistry, where long times increased thickness, but also led to a reduced sulphur and increased oxygen content because of more pronounced etching. The optimal deposition time was therefore set at 10 min resulting in the deposition of dense coatings possessing a high number of sulphur-containing functionalities. The Yasuda parameter (W/FM) analysis demonstrated optimal thiol incorporation in combination with high coating stability at an intermediate W/FM value of 72 MJ/kg. Following the determination of the optimal plasma polymerization parameters, the effectiveness of thiol plasma polymerization and subsequent fibronectin immobilization for enhancing cell adhesion and proliferation was investigated. The thiol-coated substrates were found to exhibit superior protein immobilization, because of the high affinity for protein binding of the available thiol groups. To assess cellular responses, Schwann cells were cultured on uncoated and coated samples before and after fibronectin immobilization. The results revealed a superior cellular response of the thiol-coated samples after fibronectin immobilization, showing the highest cell viability and significantly enhanced cell adhesion and proliferation. Collectively, these results underscore the synergistic effect of thiol plasma polymerization and fibronectin immobilization in promoting the cellular response of LDPE substrates, thus highlighting their potential as a surface modification strategy of biomaterials.