A Stimulus-Responsive Ternary Heterojunction Boosting Oxidative Stress, Cuproptosis for Melanoma Therapy.

Cuproptosis, a recently discovered copper-dependent cell death, presents significant potential for the development of copper-based nanoparticles to induce cuproptosis in cancer therapy. Herein, a unique ternary heterojunction, denoted as HACT, composed of core-shell Au@Cu2O nanocubes with surface-deposited Titanium Dioxide quantum dots and modified with hyaluronic acid is introduced. Compared to core-shell AC NCs, the TiO2/Au@Cu2O exhibits improved energy structure optimization, successfully separating electron-hole pairs for redox use. This optimization results in a more rapid generation of singlet oxygen and hydroxyl radicals triggering oxidative stress under ultrasound radiation. Furthermore, the HACT NCs initiate cuproptosis by Fenton-like reaction and acidic environment, leading to the sequential release of cupric and cuprous ions. This accumulation of copper induces the aggregation of lipoylated proteins and reduces iron-sulfur proteins, ultimately initiating cuproptosis. More importantly, HACT NCs show a tendency to selectively target cancer cells, thereby granting them a degree of biosecurity. This report introduces a ternary heterojunction capable of triggering both cuproptosis and oxidative stress-related combination therapy in a stimulus-responsive manner. It can energize efforts to develop effective melanoma treatment strategies using Cu-based nanoparticles through rational design.

Ternary heterostructure-driven photoinduced electron-hole separation enhanced oxidative stress for triple-negative breast cancer therapy.

Zinc oxide nanoparticles (ZnO NPs) stand as among the most significant metal oxide nanoparticles in trigger the formation of reactive oxygen species (ROS) and induce apoptosis. Nevertheless, the utilization of ZnO NPs has been limited by the shallowness of short-wavelength light and the constrained production of ROS. To overcome these limitations, a strategy involves achieving a red shift towards the near-infrared (NIR) light spectrum, promoting the separation and restraining the recombination of electron-hole (e--h+) pairs. Herein, the hybrid plasmonic system Au@ZnO (AZ) with graphene quantum dots (GQDs) doping (AZG) nano heterostructures is rationally designed for optimal NIR-driven cancer treatment. Significantly, a multifold increase in ROS generation can be achieved through the following creative initiatives: (i) plasmonic Au nanorods expands the photocatalytic capabilities of AZG into the NIR domain, offering a foundation for NIR-induced ROS generation for clinical utilization; (ii) elaborate design of mesoporous core-shell AZ structures facilitates the redistribution of electron-hole pairs; (iii) the incorporation GQDs in mesoporous structure could efficiently restrain the recombination of the e--h+ pairs; (iv) Modification of hyaluronic acid (HA) can enhance CD44 receptor mediated targeted triple-negative breast cancer (TNBC). In addition, the introduced Au NRs present as catalysts for enhancing photothermal therapy (PTT), effectively inducing apoptosis in tumor cells. The resulting HA-modified AZG (AZGH) exhibits efficient hot electron injection and e--h+ separation, affording unparalleled convenience for ROS production and enabling NIR-induced PDT for the cancer treanment. As a result, our well-designed mesoporous core-shell AZGH hybrid as photosensitizers can exhibit excellent PDT efficacy.

An enzymatically activated AND-gate DNA logic circuit for tumor cells recognition via multi-microRNAs detection.

The DNA-based logic circuit, constructed to mimic biochemical reaction networks, is highly significant in detecting biomarkers at the molecular level. The differences in the expression levels of microRNAs (miRNAs) within different types of cells provide hope for distinguishing cell subtypes. However, reliance on a single miRNA often leads to unreliable results. Herein, we constructed an enzyme-triggered cascade logic circuit based on the AND gate, which is capable of generating corresponding fluorescence signals in the presence of target miRNAs. The introduction of apurinic/apyrimidinic (AP) sites effectively reduces the likelihood of false signal generation. Amplification of the fluorescence signal relies on the catalytic hairpin assembly and the repetitive reuse of the multicomponent nucleic acid enzyme (MNAzyme). We demonstrated that the logic circuit can not only distinguish cancer cells from normal cells but also identify different types of cancer cells. The programmability of the logic circuits and the simplicity of the assay system allow us to modify the functional sequences to recognize different types of biomarkers, thus providing a reference for the identification of various cell subtypes.

A Chiral Nanocomplex for Multitarget Therapy to Alleviate Neuropathology and Rescue Alzheimer's Cognitive Deficits.

Alzheimer's disease (AD) is a severe neurodegenerative condition characterized by inflammation, beta-amyloid (Aß) plaques, and neurodegeneration, which currently lack effective treatments. Chiral nanomaterials have emerged as a promising option for treating neurodegenerative disorders due to their high biocompatibility, strong sustained release ability, and specific enantiomer selectivity. The development of a stimulus-responsive chiral nanomaterial, UiO-66-NH2 @l-MoS2 QDs@PA-Ni (MSP-U), for the treatment of AD is reported. MSP-U is found to stimulate neural stem cell (NSCs) differentiation, promote in situ hydrogen (H2 ) production, and clear Aß plaques. l-MoS2 QDs modified with l-Cysteine (l-Cys) effectively enhance the differentiation of NSCs into neurons through circularly polarized near-infrared radiation. Doped-phytic acid nickel (PA-Ni) improves the activity of l-MoS2 QDs in scavenging reactive oxygen species at the lesion site via photocatalytic H2 production. Loading l-MoS2 QDs with UiO-66 type metal oxide suppresses electron-hole recombination effect, thereby achieving rapid charge separation and improving transport of photogenerated electrons, leading to significantly improved H2 production efficiency. The photothermal effect of MSP-U also clears the generated Aß plaques. In vivo evaluations show that MSP-U improves spatial cognition and memory, suggesting a promising potential candidate for the treatment of AD using chiral nanomaterials.

Nanoprecipitated CoPi enhanced photoelectrochemical water oxidation toward sensitive and selective Co2+ detection.

The detection of heavy metal ions Co2+ is of great significance to the environment and human health. Herein, a simple, highly selective and sensitive photoelectrochemical detection strategy for Co2+ was developed based on the enhanced activity by nanoprecipitated CoPi on the Au nanoparticle decorated BiVO4 electrode. The new photoelectrochemical sensor has a low detection limit of 0.03 µΜ and wide detection range of 0.1-10, and 10-6000 µΜ, with a high selectivity over other metal ions. The Co2+ concentration in tap water and commercial drinking water has also been successfully determined with the proposed method. Scanning electrochemical microscopy technique was employed to characterize the photocatalytic performance and heterogenous electron transfer rate of electrodes in situ, further revealing the photoelectrochemical sensing mechanism. Besides determining Co2+ concentration, this approach of enhanced catalytic activity by nanoprecipitation can be further extended to develop a variety of electrochemical, photoelectrochemical and optical sensing platforms for many other hazardous ions and biological molecules.

Injectable hydroethanolic physical gels based on Codonopsis pilosula polysaccharide for sustained anticancer drug delivery.

The development of biocompatible carriers based on hydroethanolic physical gels for effectively encapsulating and delivering hydrophobic drug molecules is of particular interest. In this paper, we reported a novel hydroethanolic physical gel based on Codonopsis pilosula polysaccharide (CPP) prepared from the roots of C. pilosula. The gelation behaviors of the graded CPP fractions in a water-ethanol solvent system were evaluated, and the physicochemical and mechanical properties of the CPP-based gel (CPP-G) were characterized. The results indicated that CPP-G had consisted of a random physically crosslinked network formed by hydrophobic association of CPP chains and exhibited good mechanical strength, higher shear-thinning sensitivity and rapid, highly efficient self-recovering characteristics, ensuring superior performance in constructing injectable and self-recovering drug-loaded gels. Hydrophobic paclitaxel (PTX) and hydrophilic doxorubicin (DOX) were used as representative drugs to investigate the encapsulation and in vitro release behaviors of CPP-G, which exhibited long-term sustained release properties. Additionally, the evaluation of drug activity in drug-loaded gels further revealed the synergistic effect of CPP-G with the selected drugs on tumor inhibition against 4T1 and MCF-7 breast cancer cell lines. This work evaluated the feasibility of using the natural polysaccharide CPP to construct hydroethanolic physical gels and the applicability of the injectable drug-loaded gels for hydrophobic drug delivery.

Purification, Identification, and Properties of a Novel Carotenoid Produced by Arthrobacter sp. QL17 Isolated from Mount Qomolangma.

The genus Arthrobacter is a source of many natural products that are critical in the development of new medicines. Here, we isolated a novel carotenoid from Arthrobacter sp. QL17 and characterized its properties. The carotenoid was extracted with methanol, and purified by column chromatography and semi-preparative HPLC. Based on micrOTOF-Q and NMR analyses, the pigment was chemically characterized as 2,2'-((((1E,3E,5E,7E,9E,11E,13E,15E,17E,19E)-3,7,14,18-tetramethylicosa-1,3,5,7,9,11,13,15,17,19-decaene-1,20-diyl)bis(2,2,4-trimethylcyclohex-3-ene-3,1-diyl)) bis(ethan-2-yl-1-ylidene))bi(propane-1,3-diol), and named arthroxanthin. The biological activities of arthroxanthin were evaluated with DPPH, ABTS and MTT assays. Arthroxanthin exhibited excellent radical scavenging properties, as shown for 2, 20-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-n-(3,2-ethyl-benzothiazole-6-sulfonic acid) ammonium salt (ABTS), respectively, with IC50s of 69.8 and 21.5 µg/mL. It also showed moderate anticancer activities against HepG2, Hela, MDAB-231, SW480, and MKN-45 with IC50 values of 107.6, 150.4, 143.4, 195.9, and 145.5 µg/mL, respectively. Therefore, arthroxanthin derived from Arthrobacter sp. QL17 may be a potent antioxidant and anticancer agent for food and pharmaceutical use.

A data-driven hybrid ensemble AI model for COVID-19 infection forecast using multiple neural networks and reinforced learning.

The COVID-19 outbreak poses a huge challenge to international public health. Reliable forecast of the number of cases is of great significance to the planning of health resources and the investigation and evaluation of the epidemic situation. The data-driven machine learning models can adapt to complex changes in the epidemic situation without relying on correct physical dynamics modeling, which are sensitive and accurate in predicting the development of the epidemic. In this paper, an ensemble hybrid model based on Temporal Convolutional Networks (TCN), Gated Recurrent Unit (GRU), Deep Belief Networks (DBN), Q-learning, and Support Vector Machine (SVM) models, namely TCN-GRU-DBN-Q-SVM model, is proposed to achieve the forecasting of COVID-19 infections. Three widely-used predictors, TCN, GRU, and DBN are used as elements of the hybrid model ensembled by the weights provided by reinforcement learning method. Furthermore, an error predictor built by SVM, is trained with validation set, and the final prediction result could be obtained by combining the TCN-GRU-DBN-Q model with the SVM error predictor. In order to investigate the forecasting performance of the proposed hybrid model, several comparison models (TCN-GRU-DBN-Q, LSTM, N-BEATS, ANFIS, VMD-BP, WT-RVFL, and ARIMA models) are selected. The experimental results show that: (1) the prediction effect of the TCN-GRU-DBN-Q-SVM model on COVID-19 infection is satisfactory, which has been verified in three national infection data from the UK, India, and the US, and the proposed model has good generalization ability; (2) in the proposed hybrid model, SVM can efficiently predict the possible error of the predicted series given by TCN-GRU-DBN-Q components; (3) the integrated weights based on Q-learning can be adaptively adjusted according to the characteristics of the data in the forecasting tasks in different countries and multiple situations, which ensures the accuracy, robustness and generalization of the proposed model.

Bioinformatics and Experimental Analysis of the Prognostic and Predictive Value of the CHPF Gene on Breast Cancer.

Background: Recent studies in the United States have shown that breast cancer accounts for 30% of all new cancer diagnoses in women and has become the leading cause of cancer deaths in women worldwide. Chondroitin Polymerizing Factor (CHPF), is an enzyme involved in chondroitin sulfate (CS) elongation and a novel key molecule in the poor prognosis of many cancers. However, its role in the development and progression of breast cancer remains unclear. Methods: The transcript expression of CHPF in the Cancer Genome Atlas-Breast Cancer (TCGA-BRCA), Gene Expression Omnibus (GEO) database was analyzed separately using the limma package of R software, and the relationship between CHPF transcriptional expression and CHPF DNA methylation was investigated in TCGA-BRCA. Kaplan-Meier curves were plotted using the Survival package to further assess the prognostic impact of CHPF DNA methylation/expression. The association between CHPF transcript expression/DNA methylation and cancer immune infiltration and immune markers was investigated using the TIMER and TISIDB databases. We also performed gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis with the clusterProfiler package. Western blotting and RT-PCR were used to verify the protein level and mRNA level of CHPF in breast tissue and cell lines, respectively. Small interfering plasmids and lentiviral plasmids were constructed for transient and stable transfection of breast cancer cell lines MCF-7 and SUM1315, respectively, followed by proliferation-related functional assays, such as CCK8, EDU, clone formation assays; migration and invasion-related functional assays, such as wound healing assay and transwell assays. We also conducted a preliminary study of the mechanism. Results: We observed that CHPF was significantly upregulated in breast cancer tissues and correlated with poor prognosis. CHPF gene transcriptional expression and methylation are associated with immune infiltration immune markers. CHPF promotes proliferation, migration, invasion of the breast cancer cell lines MCF-7 and SUM1315, and is significantly enriched in pathways associated with the ECM-receptor interaction and PI3K-AKT pathway. Conclusion: CHPF transcriptional expression and DNA methylation correlate with immune infiltration and immune markers. Upregulation of CHPF in breast cancer promotes malignant behavior of cancer cells and is associated with poorer survival in breast cancer, possibly through ECM-receptor interactions and the PI3K-AKT pathway.

Ultrasensitive determination of nitrite based on electrochemical platform of AuNPs deposited on PDDA-modified MXene nanosheets.

An ultrasensitive and high-performance electrochemical nitrite sensing platform based on gold nanoparticles deposited on poly (dimethyl diallyl ammonium chloride)-decorated MXene (Ti3C2Tx) (AuNPs/Ti3C2Tx-PDDA) was constructed. AuNPs/Ti3C2Tx-PDDA on the surface of electrode displayed synergetic catalytic effect for oxidizing NO2‾ originating from especially catalytic activity of AuNPs, large area and excellent conductivity of Ti3C2Tx, as well as electrostatic interaction of PDDA. The amperometry technique was employed for quantitative determination of nitrite, in which the AuNPs/Ti3C2Tx-PDDA/GCE sensing platform showed outstanding linear relationship in 0.1-2490 µM and 2490-13490 µM for nitrite, meanwhile the detection limit of 0.059 µM. Besides, the prepared sensor possessed high sensitivity of 250 µA mM-1 cm-2 yet excellent selectivity, stability and reproducibility. Furthermore, this platform also exhibited satisfactory feasibility of nitrite sensing in running water and ham sausage sample. This work would broaden a facile approach to construct high sensitivity electrochemical sensing platform via two-dimension materials and its nanocomposites.

[Preparation of reversed-phase/hydrophilic chromatographic stationary phase based on dialdehyde microcrystalline cellulose-functionalized C18].

A novel reversed/hydrophilic chromatographic stationary phase based on dialdehyde microcrystalline cellulose (DMCC)-functionalized C18 was prepared by covalent bonding between the amino groups of octadecylamine with the aldehyde groups of DMCC, which was used in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) modes. The prepared DMCC-functionalized C18 modified silica (C18-DMCC/SiO2) stationary phase exhibited good hydrophobic selectivity and aromatic selectivity by separating alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs) in the RPLC mode. Polar compounds, including anilines, phenols, and glycosides were chosen as analytes to evaluate the polar selectivity of this column in the RPLC mode, and the evaluation results were satisfactory compared with the commercial C18 column. Nucleobases were used for evaluating the hydrophilic interaction liquid chromatography performance of the C18-DMCC/SiO2 column. By investigating the impact of organic solvent content on the retention, it could be found that this new stationary phase had the typical characteristics of reversed-phase/hydrophilic chromatography.

Hydrothermal Fabrication of Spindle-Shaped ZnO/Palygorskite Nanocomposites Using Nonionic Surfactant for Enhancement of Antibacterial Activity.

In order to improve the antibacterial performance of natural palygorskite, spindle-like ZnO/palygorskite (ZnO/PAL) nanocomposites with controllable growth of ZnO on the surface of PAL were prepared in the presence of non-ionic surfactants using an easy-to-operate hydrothermal method. The obtained ZnO/PAL nanocomposites have a novel and special spindle-shaped structure and good antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and are also low cost. The minimum inhibitory concentrations of ZnO/PAL nanocomposites toward E. coli and S. aureus reached 1.5 and 5 mg/mL, respectively.

Preparation and chromatographic performance of a multifunctional immobilized chiral stationary phase based on dialdehyde microcrystalline cellulose derivatives.

A novel high-performance liquid chromatography (HPLC) multifunctional immobilized chiral stationary phase was prepared by bonding dialdehyde microcrystalline cellulose to aminosilica via Schiff base reaction and then derivatized with 3,5-dimethylphenyl isocyanate. The HPLC multifunctional immobilized chiral stationary phase could not only achieve chiral separation but also achieve achiral separation. Chiral separation evaluation showed that 1-(1-naphthyl)ethanol and mandelonitrile got separation in normal phase (NP) mode. Ranolazine, benzoin ethyl ether, metalaxyl, and diclofop were successfully separated in reversed phase (RP) mode. Aromatic compounds such as polycyclic aromatic hydrocarbons (PAHs), anilines, and aromatic acids were selected as analytes to investigate the achiral separation performance of the multifunctional immobilized chiral stationary phase in NP and RP modes. The achiral separation evaluation showed that six PAHs could get good separation within 10 minutes in NP mode. Four aromatic acids were well separated in RP mode. The retention mechanism of aromatic compounds on the stationary phase was discussed, founding that π-π interaction, π-π electron-donor-acceptor (EDA) interaction, and hydrogen bonding interaction played important roles during the achiral separation process. This multifunctional immobilized chiral stationary phase had the advantages of simple bonding steps, short reaction time, and no need for space arm.

Hybrid Organic-Inorganic Materials Containing a Nanocellulose Derivative as Chiral Selector.

Hybrid organic-inorganic materials (HOIM), with high mechanical stability, large surface area, tailored pore size, controlled morphology, and organic loading have shown superior chiral separation performance. In this chapter, the preparation of hybrid organic-inorganic materials of core-shell silica microspheres by a layer-by-layer self-assembly method is described. The enantioseparation performance by high-performance liquid chromatography is illustrated by various types of chiral compounds under normal- and reversed-phase elution conditions. The chiral selector of nanocrystalline cellulose derivative hybrid organic-inorganic materials showed good performance in the separation of enantiomers.

Graphene quantum dots functionalized ß-cyclodextrin and cellulose chiral stationary phases with enhanced enantioseparation performance.

Graphene quantum dots (GQD) functionalized ß-cyclodextrin (ß-CD) and cellulose silica composites were first prepared and applied in HPLC as chiral stationary phases (CSP) to investigate the effect of GQDs on chiral separation. Through comparing the enantioseparation performance of GQDs functionalized ß-CD or cellulose CSPs and unmodified ß-CD or cellulose CSPs, we found GQDs enhanced the enantioseparation performance of nature ß-CD, ß-CD-3,5-dimethylphenylcarbamate derivative and cellulose-3,5-dimethylphenylcarbamate derivative. Molecular modeling was applied to understand and theoretically study the enhancement mechanism of GQDs for enantioseparation. According to molecular simulation results, GQDs provide extra interactions such as hydrophobic, hydrogen bond and π-π interaction when chiral selector interacts with enantiomers, which enhances the chiral recognition ability indirectly. The molecular simulation results showed a good agreement with the experimental results. Our work reveals the enhancement performance of GQDs for chiral separation, it can be expected that GQDs-based chiral composites and chiral GQDs have great prospect in chiral separation and other research fields such as asymmetric synthesis, chiral catalysis, chiral recognition and drug delivery.

Graphene quantum dots-functionalized C18 hydrophobic/hydrophilic stationary phase for high performance liquid chromatography.

Graphene quantum dots (GQDs) were chosen as functional material to improve the separation performance of C18 column since GQDs could provide multiple interactions such as hydrophilic, π-π stacking and hydrogen bonding interactions. In this study, a novel octadecyl modified GQDs-bonded silica (C18/GQDs/SiO2) stationary phase was prepared and applied in reversed-phase and hydrophilic interaction liquid chromatography. This column showed satisfactory separation performance for both hydrophobic, polar and hydrophilic compounds including polycyclic aromatic hydrocarbons, alkylbenzenes, anilines, phenols, aromatic acids, alkaloids, nucleosides and nucleobases. Through investigating the impact of organic solvent content on retention, it was found this new stationary phase had typical characteristics of hydrophobic/hydrophilic chromatography. Compared with commercial C18 column, this column showed better separation performance for polar aromatic compounds because the introduction of GQDs provided more interactions such as π-π stacking, hydrophilic and hydrogen bonding interaction with analytes. To get an in-depth understanding of the retention mechanism, linear solvation energy relationship model was established for both C18/GQDs/SiO2 and C18 columns, theoretically calculated data indicated that C18/GQDs/SiO2 column had higher π-π stacking and hydrogen-bonding acceptance ability. C18/GQDs composite stationary phase equipped with hydrophobic/hydrophilic properties has great prospect in separation science.

Nano-amylose-2,3-bis(3,5-dimethylphenylcarbamate)-silica hybrid sol immobilized on open tubular capillary column for capillary electrochromatography enantioseparation.

The chiral organic-inorganic hybrid materials can exhibit a high loading, and the chiral selector nanoparticles can create efficient stationary phases for open-tubular capillary electrochromatography (OT-CEC). Hence, a novel protocol for the preparation of an OT column coated with nano-amylose-2,3-bis(3,5-dimethylphenylcarbamate) (nano-ABDMPC)-silica hybrid sol through in situ layer-by-layer self-assembly method was developed for CEC enantioseparation. By controlling the assembly cycle number of nano-ABDMPC-silica hybrid sol, a homogeneous, dense and stable coating was successfully prepared, which was confirmed by SEM and elemental analysis. As the main parameter influencing the chiral separating effect, the nano-ABDMPC bearing 3-(triethoxysilyl)propyl residues concentration was investigated. The experimental results showed that 10.0 mg/mL nano-ABDMPC bearing 3-(triethoxysilyl)propyl residues coated OT capillary column possessed chiral recognition ability toward the six enantiomers (phenylalanine, tyrosine, tryptophan, phenethyl alcohol, 1-phenyl-2-propanol, and Tröger's base) at some of the different conditions tested. Additionally, the coated OT column revealed adequate repeatability concerning run-to-run, day-to-day and column-to-column. These results demonstrated the promising applicability of nano-ABDMPC-silica hybrid sol coated OT column in CEC enantioseparations.

Electrochemical sensor for discrimination tyrosine enantiomers using graphene quantum dots and ß-cyclodextrins composites.

An electrochemical sensor using the composites of graphene quantum dots (GQDs) and ß-cyclodextrins (ß-CDs) functionalized glassy carbon electrode (GCE) was developed for determination and recognition of tyrosine (Tyr) enantiomers which are biomarker of depression. The modified electrode is simple to fabricate and rapid, sensitive, selective to detect the Tyr enantiomers. In order to further validate the feasibility of the electrochemical sensor in real samples, the sensor was applied to the detection of L-Tyr in blood serum samples of healthy people and depression patients, and found that the quantities of L-Tyr of depression patients in serum is less than healthy people. The ß-CDs-GQDs composites were fabricated as modification layer of electrodes. GQDs were used as substrate and functionalized with ß-CDs. The ß-CDs-GQDs composites utilized nanosize of GQDs and enantioselectivity of ß-CDs to realize chiral recognition of Tyr. The ß-CDs-GQDs modified electrode presented significant difference in the oxidation peak current with ratio of L to D-Tyr reaching 2.35. The detection limits of L-Tyr and D-Tyr were 6.07×10-9 M and 1.03×10-7 M, respectively and superior to detection limits of the reported methods. In addition, the stability and reproducibility of the prepared modified electrode were investigated, and achieved good results.

Nanocellulose crystals derivative-silica hybrid sol open tubular capillary column for enantioseparation.

Broad spectrum separation of chiral compounds is a challenge task for analysts. It is significant for preparation of chiral stationary phase and selection of separation technology in the field. Here, we present a novel nanocellulose crystals (NCCs) which were derivation with 3,5-dimethylphenyl isocynate (DMPC) and silane with 3-triethoxysilylpropylisocyanate form sol in tetraethylorthosilicate (TEOS) and layer-by-layer self-assembly in the inner of capillary to fabricate the organic-inorganic hybrid open tubular capillary column (DMPC/NCCs-OTC) for enantiomers separation by capillary electrochromatography technology (CEC). The experimental results verified that this coating column has the broad spectrum separation ability and high resolution efficiency for thirteen different enantiomers at the optimal CEC conditions. The mechanizations of DMPC/NCCs-OTC modified layer numbers and structure effect on chiral separation performance have been investigated and compared. Although the limitation and difficulty in fabrication of open tubular coating column, this work provided the preparation method of stability, controlled, long column life, adequate repeatability and satisfied enantioseparation performance.

Multi-mode application of graphene quantum dots bonded silica stationary phase for high performance liquid chromatography.

Graphene quantum dots (GQDs), which possess hydrophobic, hydrophilic, π-π stacking and hydrogen bonding properties, have great prospect in HPLC. In this study, a novel GQDs bonded silica stationary phase was prepared and applied in multiple separation modes including normal phase, reversed phase and hydrophilic chromatography mode. Alkaloids, nucleosides and nucleobases were chosen as test compounds to evaluate the separation performance of this column in hydrophilic chromatographic mode. The tested polar compounds achieved baseline separation and the resolutions reached 2.32, 4.62, 7.79, 1.68 for thymidine, uridine, adenosine, cytidine and guanosine. This new column showed satisfactory chromatographic performance for anilines, phenols and polycyclic aromatic hydrocarbons in normal and reversed phase mode. Five anilines were completely separated within 10min under the condition of mobile phase containing only 10% methanol. The effect of water content, buffer concentration and pH on chromatographic separation was further investigated, founding that this new stationary phase showed a complex retention mechanism of partitioning, adsorption and electrostatic interaction in hydrophilic chromatography mode, and the multiple retention interactions such as π-π stacking and π-π electron-donor-acceptor interaction played an important role during the separation process. This GQDs bonded column, which allows us to adjust appropriate chromatography mode according to the properties of analytes, has possibility in actual application after further research.