CARD9 protein SUMOylation regulates HOXB5 nuclear translocation and Parkin-mediated mitophagy in myocardial I/R injury.

Myocardial injury induced by ischemia-reperfusion (I/R) remains a difficult clinical problem. However, the exact mechanisms underlying I/R-induced have yet to be clarified. CARD9 is an important cytoplasmic-binding protein. In this study, an immunocoprecipitation assay showed that SUMOylation of the CARD9 protein promoted the binding of CARD9 to HOXB5, but hindered the O-GlcNAc glycosylation of HOXB5, a predicted transcription factor of Parkin and a key factor in mitophagy. O-GlcNAc glycosylation is an important signal for translocation of proteins from the cytoplasm to the nucleus. CARD9 protein SUMOylation is regulated by PIAS3, which is related to I/R-induced myocardial injury. Therefore, we propose that knockdown of PIAS3 inhibits SUMOylation of the CARD9 protein, facilitates the dissociation of CARD9 and HOXB5, which increases the O-GlcNAc-mediated glycosylation of HOXB5, while the resulting HOXB5 nuclear translocation promotes Parkin-induced mitophagy and alleviates myocardial I/R injury.

Phosphate Ion-Selective Electrode Based on Electrochemically Modified Iron.

The significance of the detection of phosphate ions is immense in the realms of chemistry, biology, medicine, environment, and industry. The detection of phosphate ions is currently mainly reliant on blue molybdenum colorimetry, which is accurate but requires sample pretreatment, intricate operation, and a high price tag. Consequently, it is essential to create a sensor with superior efficiency, precision, straightforward functioning, and instantaneous online detection. This study has designed and created an electrochemical modification based on an iron metal electrode for this purpose. Cyclic voltammetry was used to initially ascertain the potential (-0.57 V) necessary for constant potential electrolysis. Employing a constant potential electrolysis method, the iron oxide and its phosphate were modified onto the surface of the iron electrode to enable reaction with phosphate ions. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to characterize and analyze the morphology and elemental composition of Fe-PME, elucidating how it responds to phosphate ionation. The two-electrode system was then utilized for the evaluation of the phosphate ion response of Fe-PME at pH 4. Fe-PME's response to phosphate ions is demonstrated by the results, ranging from 10-5 to 0.1 M and with a slope of -52.8 mV dec-1. Fe-PME exhibited satisfactory results when compared to the conventional blue colorimetry of molybdenum.

Abnormal phenotypic defects detection of jujube using explainable machine learning enhanced computer vision.

Jujube is susceptible to biotic and abiotic adversity stresses resulting in abnormal phenotypic defects. Therefore, abnormal phenotype fruits should be removed during postharvest sorting to increase added value. An improved maximum horizontal diameter linear regression (MHD-LR) method for size grading of jujube prior to detection of abnormal phenotypic defects was developed. The accuracy of the MHD-LR model is 95%, with an error of only 0.95 mm. In addition, a method for detecting abnormal phenotypic defects in jujube was established. It can effectively and accurately classify seven kinds of jujube phenotypes (regular, irregular, wrinkled, moldy, hole-broken, skin-broken, and scarred). The data augmentation method based on linear interpolation can effectively expand the dataset with a variance of only 0.0006. Support vector machine-decision tree (SVMDT), logistic regression, back propagation neural network, and long short-term memory network models were established to classify jujube samples with different phenotypes, with accuracies of 99.57%, 99.00%, 99.14%, and 99.29%, respectively. The results showed that the SVMDT model had higher accuracy and explainability. This research is expected to provide a new method to improve the precise classification of abnormal phenotypic defects in postharvest jujube.

Amperometric Highly Sensitive Phosphate Ion Sensor Based on the Electrochemically Modified Ni Electrode.

We present a study of high-performance electrochemical phosphate sensors, which are exquisitely designed and easy to operate. We innovatively utilized the insolubility of nickel phosphate and developed a new type of sensor through electrochemical methods. The experiment first used cyclic voltammetry to determine -0.4 V as the optimal electrochemical modification potential and used constant potential electrodeposition technology to form a nickel oxide layer on the surface of the nickel electrode, which serves as the active layer in response to phosphate ions. The changes in the surface structure and chemical composition of the electrode before and after modification were thoroughly characterized by scanning electron microscopy and energy scattering spectroscopy analysis. The performance evaluation of the sensor shows that the modified nickel electrode has excellent responsiveness to phosphate ions in the concentration range of 10-7 to 10-10 mol/L, with a detection lower limit of 10-10 mol/L. As the concentration decreases, a shoulder peak appears at ∼0.63 V and the current change shows a regular increase. Compared with traditional detection methods, this sensor exhibits higher stability and practicality and is suitable for the rapid identification of phosphates in real samples. In summary, this study successfully developed a fast, sensitive, and wide response range current type electrochemical phosphate sensor, which has broad application prospects in environmental monitoring, water quality analysis, and biomedical fields.

UV-ozone sterilization system: An intelligent solution for Northern shrimp (Pandalus borealis) cold chain transportation emergencies.

Sterilization of Northern shrimp (Pandalus borealis) is a key tool to ensure their freshness for post-production transportation. However, in the face of the specific problem of quality deterioration caused by the increase of storage environment temperature due to unexpected circumstances or the prolongation of temporary storage time, it is still a technical challenge to realize intelligent decision-making and higher sterilization efficiency. In this paper, we propose an intelligent UV-Ozone sterilization system suitable for cold chain transportation of Northern shrimp (Pandalus borealis). Using hierarchical analysis, equipartition method and the prediction method of generalized linear model, combined with the technology of intelligent control and remote control, we realized the automatic control of the system's UV irradiance from 324 âˆ¼ 1620 J/m2, and ozone concentration from21.4 ∼ 107 mg/cm3 in a graded manner. The accuracy of the predicted structure was verified using a combination of direct measurement and simulation. In addition, the key model of the system, the intensity level decision model, was tested, and the test results showed that the decision model was able to accurately make decisions during the sterilization of Northern shrimp (Pandalus borealis), and the system was able to achieve a sterilization effect of 1-3 orders of magnitude. This reduces quality loss due to unexpected conditions, facilitates real-time monitoring of transported samples by staff, extends the shelf life of the samples, and improves the accuracy of sterilization, increasing the economic value of Northern shrimp (Pandalus borealis).

Damage Self-Healing Property of Dissolved Salt Columns in Solid Potash Mine.

The objective of this work was to investigate the self-healing properties and mechanical damage characteristics of dissolved salt columns under different humidity and time conditions. Based on the results of electron microscope scanning and uniaxial mechanical tests, the microscopic element distribution of the ore and the microscopic morphology of the minerals were investigated, and the healing, mechanical, and damage properties of the specimens were analyzed, which revealed the microscopic reinforcement mechanism of the damage healing of the dissolved salt columns. The results showed that the healing reinforcement, compressive strength, and modulus of elasticity of dissolved salt columns under uniaxial compression show a tendency to increase, then decrease with the increase of humidity, and gradually increase with the increase of the maintenance time and reach the maximum value at 10% humidity and 30 days of maintenance time, which are 3.48, 8.07, and 650 MPa, respectively. The damage type of the healed specimen as a whole gradually transitioned from tensile damage to shear-slip type, indicating that the brittle damage characteristics of the specimen under loading became more and more significant. Based on the principle of strain equivalence, the damage evolution equation under uniaxial compression of solid potash dissolved salt columns describes the damage evolution law and destruction process of the specimen, and the results of the damage characterization of the dissolved salt columns are consistent with the change rule of the healing properties and mechanical properties with humidity and conservation time. Based on the fine morphological features of the dissolved salt column specimens after self-healing, three different self-healing microscopic mechanisms for damage recovery of solid potash dissolved salt columns are summarized, namely, healing of damaged microcracks based on diffusion, recrystallization healing of brine-filled microfractures, and healing adhesion of crystal particles in dissolved zones. These microstructures effectively transform cracks into isolated sections and play a key role in improving mechanical properties. In addition, the higher the humidity, the thicker adsorbed water film is produced on the fissure surface, which accelerates the transportation of materials on the fissure surface, and the healing rate of the dissolved salt columns increases. However, when the humidity is too high, it causes the evaporation of the liquid film to be less than the recharge of water vapor, which reduces the healing rate of the dissolved salt columns. Thus, suitable humidity produces a more pronounced healing effect than an environment maintained at a constant high humidity level. The research results can provide theoretical guidance for the filling mining of solid potassium salt.

Diagnostic value of combined ultrasound contrast and elastography for differentiating benign and malignant thyroid nodules: a meta-analysis.

The diagnostic value of contrast-enhanced ultrasound combined with ultrasound elastography for benign and malignant thyroid nodules is still controversial, so we used meta-analysis to seek controversial answers. The PubMed, OVID, and CNKI databases were searched according to the inclusion and exclusion criteria. The literature was selected from the establishment of each database to February 2024. The QUADAS-2 tool assessed diagnostic test accuracy. SROC curves and Spearman's correlation coefficient were made by Review Manager 5.4 software to assess the presence of threshold effects in the literature. Meta-Disc1.4 software was used for Cochrane-Q and χ2 tests, which be used to evaluate heterogeneity, with P-values and I2 indicating heterogeneity levels. The appropriate effect model was selected based on the results of the heterogeneity test. Stata18.0 software was used to evaluate publication bias. The diagnostic accuracy of contrast-enhanced ultrasound combined with ultrasound elastography for benign and malignant thyroid nodules was evaluated by calculating the combined sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, DOR, and area under the SROC curve. A total of 31 studies included 3811 patients with 4718 nodules were analyzed. There is no heterogeneity caused by the threshold effect, but there is significant non-threshold heterogeneity. Combined diagnostic metrics were: sensitivity = 0.93, specificity = 0.91, DOR = 168.41, positive likelihood ratio = 10.60, and negative likelihood ratio = 0.07. The SROC curve area was 0.97. Contrast-enhanced ultrasound and elastography show high diagnostic accuracy for thyroid nodules, offering a solid foundation for early diagnosis and treatment.Trial registration. CRD42024509462.

Efficacy and safety of carrimycin in ten patients with severe pneumonia following solid organ transplantation.

BACKGROUND: The number of patients undergoing solid organ transplantation has increased annually. However, infections in solid organ transplant recipients can have a severe effect on patient survival owing to the continued use of immunosuppressants. Carrimycin is a novel macrolide antibiotic produced by genetically engineered streptomyces spiramyceticus harboring a 4''-O-isovaleryltransferase gene (ist) from streptomyces thermotoleran. Carrimycin has good antibacterial and antiviral effects. However, no relevant studies have been conducted on the efficacy and safety of carrimycin in patients with severe pneumonia (SP) after solid organ transplantation. AIM: To explore the efficacy and safety of carrimycin in patients with SP after solid organ transplantation to provide a medication reference for clinical treatment. METHODS: In March 2022, ten patients with SP following solid-organ transplantation were treated at our hospital between January 2021 and March 2022. When the condition was critical and difficult to control with other drugs, carrimycin was administered. These ten patients' clinical features and treatment protocols were retrospectively analyzed, and the efficacy and safety of carrimycin for treating SP following solid organ transplantation were evaluated. RESULTS: All ten patients were included in the analysis. Regarding etiological agent detection, there were three cases of fungal pneumonia, two cases of bacterial pneumonia, two cases of Pneumocystis pneumonia, and three cases of mixed infections. After treatment with carrimycin, the disease in seven patients significantly improved, the course of the disease was significantly shortened, fever was quickly controlled, chest computed tomography was significantly improved, and oxygenation was significantly improved. Finally, the patients were discharged after curing. One patient died of acute respiratory distress syndrome, and two patients discontinued treatment. CONCLUSION: Carrimycin is a safe and effective treatment modality for SP following solid organ transplantation. Carrimycin may have antibacterial and antiviral effects in patients with SP following solid organ transplantation.

Multi-scale bioimpedance flexible sensing with causal hierarchical machine learning for fish vitality evaluation under adversity stress.

It is expected that waterless low-temperature stressful environments will induce stress responses in fish and affect their vitality. In this study, we developed a laser-activated, stretchable, highly conductive liquid metal (LM) based flexible sensor system for fish multi-scale bioimpedance detection. It has excellent conformability, electrical conductivity, bending and cyclic tensile stability. Meanwhile, test result showed that wireless power supply is a potential solution for realizing safe power supply for devices inside waterless low-temperature packages. In addition, a hierarchical regression model (GC-HRM) based on Granger causality was established. The result showed that tissue bioimpedance can induce changes in individual bioimpedance with unidirectional Granger causality. The R2 of the linear regression (LR), support vector regression (SVR) and artificial neural network (ANN) models under single-scale individual bioimpedance were 0.85, 0.90 and 0.78, respectively. By adding the multi-scale bioimpedance features, the R2 of the LR, SVR and ANN models were improved to 0.95, 1.00 and 0.98, respectively.

Association between Whole Grain Intake and Chronic Kidney Disease.

BACKGROUND: The relationship between whole grain intake and chronic kidney disease (CKD) remains uncertain. OBJECTIVE: This study aimed to evaluate the association between whole grain intake and risk of CKD in Chinese adults. METHODS: The present cross-sectional study used data from the China Health and Nutrition Survey conducted in 2009. Whole grain intake was measured using 3 consecutive 24-h dietary recalls and a household food inventory. A multivariable logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for risk of CKD. In addition, a restricted cubic spline was used to investigate the dose‒response relationship between whole grain and risk of CKD. RESULTS: A total of 6747 participants were included, 728 of whom had CKD. Compared with those in the lowest whole grain intake group, those in the higher grain intake group had an inverse association with risk of CKD (Q2: adjusted OR 0.70, 95% CI: 0.54, 0.89; Q3: adjusted OR 0.54, 95% CI: 0.42, 0.69; and Q4: adjusted OR 0.29, 95% CI: 0.21, 0.41). The association between whole grain intake and CKD seems to be stronger for individuals who were male (P for interaction = 0.008) or smokers (P for interaction = 0.013). In addition, the restricted cubic spline suggested an obvious L-shaped correlation. CONCLUSIONS: Increased whole grain intake was associated with a decreased risk of CKD in Chinese adults.

Island-Like Heterogeneous Interface Generating Tandem Toroidal Built-In Electric Field for Efficient Potassium Ions Diffusion.

For large-size potassium accommodation, heterostructure usually suffers severe delamination and exfoliation at the interfaces due to different volume expansion of two-phase during charge/discharge process, resulting in the deconstruction of heterostructures and shortened lifespan of batteries. Here, an innovative strategy is proposed through constructing a microscopic heterostructure system containing copper quantum dots (Cu QDs) highly dispersed in the triphenyl-substituted triazine graphdiyne (TPTG) substrates (TPTG@CuQDs) to solve this problem. The copper quantum dots are uniformly anchored on TPTG substrates, generating a myriad of island-like heterogeneous structures, together with tandem toroidal built-in electric field (BIEF) between every micro heterointerface. The island-like heterostructure endows both benefits of exposed contact interface and robust architecture. Generated tandem toroidal BIEF provides efficient transport pathways with lower energy barriers, reducing the diffusion resistance and facilitating the reaction kinetics of potassium ions. When used as anode, the TPTG@CuQDs exhibit highly reversible capacity and low-capacity degradation (≈0.01% over 5560 cycles at 1 A g-1). Moreover, the TPTG@CuQDs-based full cell delivers an outstanding reversible capacity of ≈110 mAh g-1 over 800 cycles at 1 A g-1. This quantum-scale heterointerface construction strategy offers a new approach toward stable heterostructure design for the application of metal ion batteries.

Microcrystalline Nanofiber Electrode with Adaptive Intrinsic Structure and Microscopic Interface.

A strategy of microcrystalline aggregation is proposed to fabricate energy storage electrode with outstanding capacity and stability. Carbon-rich electrode (BDTG) functionalized with benzo[1,2-b:4,5-b']dithiophene units and butadiyne segments are prepared. The linear conjugate chains pack as microcrystalline nanofibers on nanoscale, which further aggregates to form a porous interpenetrating network. The microcrystalline aggregation feature of BDTG exhibit stable structure during long cycling test, revealing the following advantage in structure and property. The stretchable butadiyne linker facilitates reversible adsorption and desorption of Li with the aid of adjacent sulfur heteroatom. The alkyne-alkene transition exhibits intrinsic structural stability of microcrystalline region in BDTG electrodes. Meanwhile, alkynyl groups and sulfur heteroatoms on the surface of BDTG nanofibers participate in the formation of microscopic interface, providing a stable interfacial contact between BDTG electrodes and adjacent electrolyte. As a proof-of-concept, BDTG-based electrode shows high capacity (1430 mAh g-1 at 50 mA g-1) and excellent cycle performance (8000 cycles under 5 A g-1) in half-cell of lithium-ion batteries, and a reversible capacity of 120 mAh g-1 is obtained under the current density of 2 C in full-cell. This work shows microcrystalline aggregation is beneficial to realize adaptive intrinsic structure and interface contact during the charge-discharge process.

Design, synthesis, and application of some two-dimensional materials.

Two-dimensional (2D) materials are widely used as key components in the fields of energy conversion and storage, optoelectronics, catalysis, biomedicine, etc. To meet the practical needs, molecular structure design and aggregation process optimization have been systematically carried out. The intrinsic correlation between preparation methods and the characteristic properties is investigated. This review summarizes the recent research achievements of 2D materials in the aspect of molecular structure modification, aggregation regulation, characteristic properties, and device applications. The design strategies to fabricate functional 2D materials starting from precursor molecules are introduced in detail referring to organic synthetic chemistry and self-assembly technology. It provides important research ideas for the design and synthesis of related materials.

Study on Damage Characteristics and Failure Modes of Gypsum Rock under Dynamic Impact Load.

The objective of this work was to investigate the damage characteristics and failure modes of gypsum rock under dynamic impact loading. Split Hopkinson pressure bar (SHPB) tests were performed under different strain rates. The strain rate effects on the dynamic peak strength, dynamic elastic modulus, energy density, and crushing size of gypsum rock were analyzed. A numerical model of the SHPB was established using the finite element software, ANSYS 19.0, and its reliability was verified by comparing it to laboratory test results. The results showed that the dynamic peak strength and energy consumption density of gypsum rock increased exponentially with strain rate, and the crushing size decreased exponentially with the strain rate, both findings exhibited an obvious correlation. The dynamic elastic modulus was larger than the static elastic modulus, but did not show a significant correlation. Gypsum rock fracture can be divided into crack compaction, crack initiation, crack propagation, and breaking stages, and is dominated by splitting failure. With increasing strain rate, the interaction between cracks is noticeable, and the failure mode changes from splitting to crushing failure. These results provide theoretical support for improvements of the refinement process in gypsum mines.

rGO-PDMS Flexible Sensors Enabled Survival Decision System for Live Oysters.

The shell-closing strength (SCS) of oysters is the main parameter for physiological activities. The aim of this study was to evaluate the applicability of SCS as an indicator of live oyster health. This study developed a flexible pressure sensor system with polydimethylsiloxane (PDMS) as the substrate and reduced graphene oxide (rGO) as the sensitive layer to monitor SCS in live oysters (rGO-PDMS). In the experiment, oysters of superior, medium and inferior grades were selected as research objects, and the change characteristics of SCS were monitored at 4 °C and 25 °C. At the same time, the time series model was used to predict the survival rate of live oyster on the basis of changes in their SCS characteristics. The survival times of superior, medium and inferior oysters at 4 °C and 25 °C were 31/25/18 days and 12/10/7 days, respectively, and the best prediction accuracies for survival rate were 89.32%/82.17%/79.19%. The results indicate that SCS is a key physiological indicator of oyster survival. The dynamic monitoring of oyster vitality by means of flexible pressure sensors is an important means of improving oyster survival rate. Superior oysters have a higher survival rate in low-temperature environments, and our method can provide effective and reliable survival prediction and management for the oyster industry.

Influence of Section Shape and Buried Depth on Rock Loosening Zone around Underground Roadway in Coal Mine.

Owing to differences in deformation characteristics of roadways with different section shapes and depths, it is difficult to determine the support form and grouting depth of a roadway, which can cause serious deformation to the roadway. To address the challenges in determining the shape and grouting depth of a roadway section when the mine depth is known, the loose zone range of the roadway was tested using the acoustic method, and the loose zone evolution law under different conditions was performed by numerical simulations. The research results revealed that when the ratio of the maximum principal stress to the minimum principal stress is η > 3, the distribution of the rock loosening zone under different cross-sectional shapes was roughly "butterfly-shaped", and the "smoother" the cross section in the design of the roadway, the smaller the range of the rock loosening zone. With the increase of burial depth, the rock loosening zone and sealing depth also increase; the rock loosening zone and burial depth have a power function relationship the rock loosening zone range = a·burial depth b ; the sealing depth and burial depth have a linear relationship R = aH + b.

Tuning Intermolecular Interactions to Enhance the Cyclability of Non-Aqueous, Organic Redox Flow Batteries.

Enhancing the electrochemical stability and reversibility of redox-active organic molecules is crucial to improve the performance of non-aqueous redox flow batteries (RFBs). Compared with the widely adopted strategy of molecular engineering, we show in this study that tuning the intermolecular interaction between the active material with the supporting electrolyte is another feasible way to address the performance of non-aqueous organic RFBs. Combined with theoretical and experimental investigations, the influence of Lewis acidity of the supporting electrolyte cations and anions on the electrochemical stability and reversibility of bipyridine-based anode material is revealed. As a demonstration, a redox flow cell based on 4,4'-bipyridine anolyte and ferrocene catholyte shows greatly enhanced performance by using supporting electrolyte composed of soft Lewis acid and soft Lewis base. This study provides an alternative, yet highly effective way to addressing the cyclability of an organic compound for non-aqueous RFBs.

MMP-2 Inhibitor-Mediated Tumor Microenvironment Regulation Using a Sequentially Released Bio-Nanosystem for Enhanced Cancer Photo-Immunotherapy.

Combining photodynamic therapy (PDT) with natural killer (NK) cell-based immunotherapy has shown great potential against cancers, but the shedding of NK group 2, member D ligands (NKG2DLs) on tumor cells inhibited NK cell activation in the tumor microenvironment. Herein, we assembled microenvironment-/light-responsive bio-nanosystems (MLRNs) consisting of SB-3CT-containing ß-cyclodextrins (ß-CDs) and photosensitizer-loaded liposomes, in which SB-3CT was considered to remodel the tumor microenvironment. ß-CDs and liposomes were linked by metalloproteinase 2 (MMP-2) responsive peptides, enabling sequential release of SB-3CT and chlorin e6 triggered by the MMP-2-abundant tumor microenvironment and 660 nm laser irradiation, respectively. Released SB-3CT blocked tumor immune escape by antagonizing MMP-2 and promoting the NKG2D/NKG2DL pathway, while liposomes were taken up by tumor cells for PDT. MLRN-mediated photo-immunotherapy significantly induced melanoma cell cytotoxicity (83.31%), inhibited tumor growth (relative tumor proliferation rate: 1.13% of that of normal saline) in the xenografted tumor model, and enhanced tumor-infiltrating NK cell (148 times) and NKG2DL expression (9.55 and 16.52 times for MICA and ULBP-1, respectively), achieving a synergistic effect. This study not only provided a simple insight into the development of new nanomedicine for programed release of antitumor drugs and better integration of PDT and immunotherapy but also a novel modality for clinical NK cell-mediated immunotherapy against melanoma.

Facile Fabrication of Hierarchically Porous Boronic Acid Group-Functionalized Monoliths With Optical Activity for Recognizing Glucose With Different Conformation.

At present, various materials based on helical polymers are nanoparticle or microsphere, which is not ease of use in practical application. Accordingly, facile preparation hierarchically porous monolith based on helical polymer needs to be developed. Herein, hierarchically porous boronic acid group-functionalized monoliths that exhibited optical activity were fabricated with a facile method based on crosslinking and polymerization-induced phase separation (CPIPS). Chiral substituted acetylene and achiral substituted acetylene with a boronic acid group were used as monomers. By regulating the composition of the pre-polymerization solution, the permeability and macropore size of the porous structure could be controlled. The hierarchically porous structure and large surface area were confirmed by scanning electron microscopy and nitrogen gas adsorption/desorption isotherms. In particular, the boronic acid functional group that can interact with a cis-diol group was successfully introduced on the skeleton surface of the monoliths. Further, the main chain of the copolymer that constituted the monoliths exhibited a high cis content and tacticity, and the monoliths showed good optical activity. Thus, the present study established a facile method to synthesize hierarchically porous boronic acid group-functionalized monoliths with optical activity via CPIPS, and the monoliths showed potential in recognition, separation, and adsorption of compound with chirality and cis-diol groups.

Robust Dual-Biomimetic Titanium Dioxide-Cellulose Monolith for Enrichment of Phosphopeptides.

Metal oxide affinity chromatography (MOAC) is considered to be one of the most effective methods for phosphopeptide enrichment. However, most of the materials used in the method are powder; frequent centrifugation is necessitated during the enrichment process, and potential risks of loss of peptides and materials and clogging of the column employed for liquid chromatography-mass spectrometry (LC-MS) arise. Moreover, the reusability of these materials to achieve sustainability was hardly investigated. To overcome these limitations, herein, inorganic titanium dioxide (TiO2) was coated onto the skeletal surface of the organic cellulose monolith (CM) material with a coral-like structure via a sol-gel method. This produced an organic-inorganic hybrid TiO2-CM material, which contained a combination of organic and inorganic substances, making it mimic the mollusk shell in terms of composition. The prepared TiO2-CM material as monolith exhibited excellent mechanical strength and did not break during the enrichment process; thus, the tedious implementation of multiple centrifugation cycles was prevented, thereby streamlining the experimental procedure and avoiding the loss of peptides and materials. Moreover, a large amount of TiO2 was introduced onto the surface of the CM material, and thus, the resultant TiO2-CM material exhibited a large surface area. As a result, the fabricated TiO2-CM material was successfully applied to the enrichment of phosphopeptides obtained from the tryptic digests of a BSA/ß-casein (mass ratio, 500/1) mixture. The results were superior to those achieved for commercial TiO2 beads, confirming that TiO2-CM has excellent selectivity for phosphopeptides and reusability. Furthermore, 9287 unique phosphopeptides derived from the 2661 phosphoproteins were successfully identified from two milligrams of tryptic digests of Hela cell exosomes obtained through five independent replications after enriching using the TiO2-CM material. The results indicated that the material has good application prospects in the analysis of protein phosphorylation. Furthermore, TiO2-CM consists of green and cheap cellulose as the skeleton, and its synthesis process is environment-friendly, simple, and inexpensive.