An obituary: Dr. Helmut Cölfen 1965-2023.

Dr. Helmut Cölfen, an exceptional interdisciplinary scientist, mentor, colleague, and dear friend, passed away in November 2023 at the age of 58. His untimely departure is a profound loss for the fields of analytical ultracentrifugation, colloid, crystallization, and polymer research. This obituary pays tribute to Helmut, honoring his remarkable academic career and contributions to the study of nanochemistry, biophysics, and life sciences. Helmut was renowned for his pioneering research contributions in several key research areas: (1) Development of advanced analytical techniques: Helmut made major contributions to techniques such as analytical ultracentrifugation and field flow fractionation, which are widely utilized to characterize the structure of biomolecules and the growth of nanostructured crystalline materials; (2) Study of nucleation and crystallization processes: Helmut explored the early stages of crystallization which led to the discovery of pre-nucleation clusters and mesocrystal intermediates, in the presence of additives and templates; and (3) Investigation of structure and morphogenesis of mesocrystals, examining their molecular properties.

Parenting beliefs and practices as precursors to academic outcomes in Chinese children.

Due to the rapid sociocultural changes in China, Chinese parents' childrearing beliefs and practices have undergone dramatic transformations. Against this context, this study examined whether Chinese parents' endorsement of progressive and traditional childrearing beliefs would predict children's academic achievement, as well as whether parenting practices would mediate this association. This study utilized a longitudinal design and followed 206 Chinese families for 2 years from the end of preschool to Grade 2. Parents showed greater endorsement of progressive than traditional childrearing beliefs, as well as higher use of authoritative than authoritarian parenting practices. Parents' childrearing beliefs in preschool predicted children's math achievement in Grade 2 via authoritative parenting. However, parenting beliefs were unrelated to authoritarian parenting, and authoritarian parenting did not predict any of the child academic outcomes in Grade 2. The findings suggest Chinese parents' orientations toward progressive parenting beliefs and authoritative parenting practices. They also highlight the utility of parenting beliefs in explaining disparities in early academic achievement. The nonsignificant findings pertinent to authoritarian parenting call for re-examination of the cultural meaning and effects of authoritarian parenting in Chinese society.

Bta-miR-365-3p-targeted FKBP5 participates in the AMPK/mTOR signaling pathway in the regulation of preadipocyte differentiation in cattle.

Objective: MicroRNAs (miRNAs) are endogenous non-coding RNAs that can play a role in the post-transcriptional regulation of mammalian preadipocyte differentiation. However, the precise functional mechanism of its regulation of fat metabolism is not fully understood. Methods: We identified bta-miR-365-3p, which specifically targets the 3'untranslated region (3'UTR) of the FK506-binding protein 5 (FKBP5),and verified its mechanisms for regulating expression and involvement in adipogenesis. Results: In this study, we found that the overexpression of bta-miR-365-3p significantly decreased the lipid accumulation and triglyceride content in the adipocytes. Compared to inhibiting bta-miR-365-3p group, overexpression of bta-miR-365-3p can inhibit the expression of adipocyte differentiation-related genes C/EBPα and PPARγ. The dual-luciferase reporter system further validated the targeting relationship between bta-miR-365-3p and FKBP5. FKBP5 mRNA and protein expression were detected by qRT-PCR and Western blot. Overexpression of bta-miR-365-3p significantly down-regulated FKBP5 expression, while inhibition of bta-miR-365-3p showed the opposite, indicating that bta-miR-365-3p negatively regulates FKBP5. AMPK/mTOR signaling pathway is closely related to the regulation of cell growth and is involved in the development of bovine adipocytes. In this study, overexpression of bta-miR-365-3p significantly inhibited mRNA and protein expression of AMPK, mTOR, and SREBP1 genes, while the inhibition of bta-miR-365-3p expression was contrary to these results. Overexpression of FKBP5 significantly upregulated AMPK, mTOR, and SREBP1 gene expression, while inhibition of FKBP5 expression was contrary to the above experimental results. Conclusion: In conclusion, these results indicate that bta-miR-365-3p may be involved in the AMPK/mTOR signaling pathway in regulating Yanbian yellow cattle preadipocytes differentiation by targeting the FKBP5 gene.

CVD Synthesis of Twisted Bilayer WS2 with Tunable Second Harmonic Generation.

The introduction of rotational freedom by twist angles in twisted bilayer (TB) transition metal dichalcogenides (TMDCs) can tailor the inherent properties of the TMDCs, which provides a promising platform to investigate the exotic physical properties. However, direct synthesis of high-quality TB-TMDCs with full twist angles is significantly challenging due to the substantial energy barriers during crystal growth. Here, a modified chemical vapor deposition strategy is proposed to synthesize TB-WS2 with a wide twist angle range from 0° to 120°. Utilizing a tilted SiO2/Si substrate, a gas flow disturbance is generated in the furnace tube to create a heterogeneous concentration gradient of the metal precursor, which provides an extra driving force for the growth of TB-WS2. The Raman and photoluminescence results confirm a weak interlayer coupling of the TB-WS2. High-quality periodic Moiré patterns are observed in the scanning transmission electron microscopy images. Moreover, owing to the strong correlation between the nonlinear optical response and the twisted crystal structure, tunable second harmonic generation behaviors are realized in the TB-WS2. This approach opens up a new avenue for the direct growth of high-crystalline-quality and pristine TB-TMDCs and their potential applications in nonlinear optical devices.

Approaching Effective Differential Centrifugal Fractionation by Combining Image Analysis with Analytical Ultracentrifugation.

Centrifugation is one of the most commonly used methods for separation in biology and chemistry. However, effective fractionation is not always easy to obtain, as preparative centrifuge experiments are mostly conducted in an empirical way, even when it is guided by the quantitative results from analytical ultracentrifuge (AUC). Very few works have been performed to enhance the fractionation resolution of the differential centrifugation method in a swing-out rotor. This is primarily due to the absence of a characterization tool for sedimentation in the preparative centrifuge. In this study, we utilized image analysis to map the particle concentration distribution throughout the preparative centrifuge tube, revealing an unexpected and abnormal sedimentation process. By characterizing the sedimentation coefficient distributions of the fractionated product via AUC, we demonstrated that the overall sedimentation efficiency in a swing-out preparative centrifuge was significantly reduced. Furthermore, effective fractionation was confined to the intermediate phase of the entire sedimentation process. We propose that the mechanism here is a combination of the inverse Boycott effect and droplet sedimentation. The actual sedimentation process within a preparative centrifuge can be described by modifying the Lamm equation phenomenologically, which simply results in an effective sedimentation coefficient. Our work builds a foundation for determining the optimal preparative centrifugation conditions for various systems.

BPTF Drives Gastric Cancer Resistance to EGFR Inhibitor by Epigenetically Regulating the C-MYC/PLCG1/Perk Axis.

Erlotinib, an EGFR tyrosine kinase inhibitor, is used for treating patients with cancer exhibiting EGFR overexpression or mutation. However, the response rate of erlotinib is low among patients with gastric cancer (GC). The findings of this study illustrated that the overexpression of bromodomain PHD finger transcription factor (BPTF) is partially responsible for erlotinib resistance in GC, and the combination of the BPTF inhibitor AU-1 with erlotinib synergistically inhibited tumor growth both in vivo and in vitro. AU-1 inhibited the epigenetic function of BPTF and decreased the transcriptional activity of c-MYC on PLCG1 by attenuating chromosome accessibility of the PLCG1 promoter region, thus decreasing the expression of p-PLCG1 and p-Erk and eventually improving the sensitivity of GC cells to erlotinib. In patient-derived xenograft (PDX) models, AU-1 monotherapy exhibited remarkable tumor-inhibiting activity and is synergistic anti-tumor effects when combined with erlotinib. Altogether, the findings illustrate that BPTF affects the responsiveness of GC to erlotinib by epigenetically regulating the c-MYC/PLCG1/pErk axis, and the combination of BPTF inhibitors and erlotinib is a viable therapeutic approach for GC.

Screening and Validation of Appropriate Reference Genes for Real-Time Quantitative PCR under PEG, NaCl and ZnSO4 Treatments in Broussonetia papyrifera.

Real-time quantitative PCR (RT-qPCR) has a high sensitivity and strong specificity, and is widely used in the analysis of gene expression. Selecting appropriate internal reference genes is the key to accurately analyzing the expression changes of target genes by RT-qPCR. To find out the most suitable internal reference genes for studying the gene expression in Broussonetia papyrifera under abiotic stresses (including drought, salt, and ZnSO4 treatments), seven different tissues of B. papyrifera, as well as the roots, stems, and leaves of B. papyrifera under the abiotic stresses were used as test materials, and 15 candidate internal reference genes were screened based on the transcriptome data via RT-qPCR. Then, the expression stability of the candidate genes was comprehensively evaluated through the software geNorm (v3.5), NormFinder (v0.953), BestKeeper (v1.0), and RefFinder. The best internal reference genes and their combinations were screened out according to the analysis results. rRNA and Actin were the best reference genes under drought stress. Under salt stress, DOUB, HSP, NADH, and rRNA were the most stable reference genes. Under heavy metal stress, HSP and NADH were the most suitable reference genes. EIF3 and Actin were the most suitable internal reference genes in the different tissues of B. papyrifera. In addition, HSP, rRNA, NADH, and UBC were the most suitable internal reference genes for the abiotic stresses and the different tissues of B. papyrifera. The expression patterns of DREB and POD were analyzed by using the selected stable and unstable reference genes. This further verified the reliability of the screened internal reference genes. This study lays the foundation for the functional analysis and regulatory mechanism research of genes in B. papyrifera.

A senescence-based prognostic gene signature for colorectal cancer and identification of the role of SPP1-positive macrophages in tumor senescence.

Background: Senescence is significantly associated with cancer prognosis. This study aimed to construct a senescence-related prognostic model for colorectal cancer (CRC) and to investigate the influence of senescence on the tumor microenvironment. Methods: Transcriptome and clinical data of CRC cases were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Senescence-related prognostic genes detected by univariate Cox regression were included in Least Absolute Shrinkage and Selection Operator (LASSO) analysis to construct a model. The efficacy of the model was validated using the receiver operating characteristic (ROC) curve and survival analysis. Differentially expressed genes (DEGs) were identified and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed. CIBERSORT and Immuno-Oncology Biological Research (IOBR) were used to investigate the features of the tumor microenvironment. Single-cell RNA-seq data were used to investigate the expression levels of model genes in various cell types. Immunofluorescence staining for p21, SPP1, and CD68 was performed with human colon tissues. Results: A seven-gene (PTGER2, FGF2, IGFBP3, ANGPTL4, DKK1, WNT16 and SPP1) model was finally constructed. Patients were classified as high- or low-risk using the median score as the threshold. The area under the ROC curve (AUC) for the 1-, 2-, and 3-year disease-specific survival (DSS) were 0.731, 0.651, and 0.643, respectively. Survival analysis showed a better 5-year DSS in low-risk patients in the construction and validation cohorts. GO and KEGG analyses revealed that DEGs were enriched in extracellular matrix (ECM)-receptor interactions, focal adhesion, and protein digestion and absorption. CIBERSORT and IOBR analyses revealed an abundance of macrophages and an immunosuppressive environment in the high-risk subgroup. Low-risk patients had higher response rates to immunotherapy than high-risk patients. ScRNA-seq data revealed high expression of SPP1 in a subset of macrophages with strong senescence-associated secretory phenotype (SASP) features. Using CRC tumor tissues, we discovered that SPP1+ macrophages were surrounded by a large number of senescent tumor cells in high-grade tumors. Conclusion: Our study presents a novel model based on senescence-related genes that can identify CRC patients with a poor prognosis and an immunosuppressive tumor microenvironment. SPP1+ macrophages may correlate with cell senescence leading to poor prognosis.

Quasi-One-Dimensional van der Waals Transition Metal Trichalcogenides.

The transition metal trichalcogenides (TMTCs) are quasi-one-dimensional (1D) MX3-type van der Waals layered semiconductors, where M is a transition metal element of groups IV and V, and X indicates chalcogen element. Due to the unique quasi-1D crystalline structures, they possess several novel electrical properties such as variable bandgaps, charge density waves, and superconductivity, and highly anisotropic optical, thermoelectric, and magnetic properties. The study of TMTCs plays an essential role in the 1D quantum materials field, enabling new opportunities in the material research dimension. Currently, tremendous progress in both materials and solid-state devices has been made, demonstrating promising applications in the realization of nanoelectronic devices. This review provides a comprehensive overview to survey the state of the art in materials, devices, and applications based on TMTCs. Firstly, the symbolic structure, current primary synthesis methods, and physical properties of TMTCs have been discussed. Secondly, examples of TMTC applications in various fields are presented, such as photodetectors, energy storage devices, catalysts, and sensors. Finally, we give an overview of the opportunities and future perspectives for the research of TMTCs, as well as the challenges in both basic research and practical applications.

In-Plane Anisotropic Rectification and Photovoltaic Effects on ZnO Nonpolar (101Ì 0) Crystal Plane and the Physical Mechanism.

The concept of spontaneous electric field (Es) in polar structures is crucial for understanding the physical and chemical properties of compound semiconductors and improving their performanes. However, this concept has not been widely accepted so far. Here, we show the first observation of rectification and photovoltaic effects in the polar [0001] direction on the nonpolar ZnO (1010) crystal plane. However, no rectification and photovoltaic effects are observed in the nonpolar [1210] direction perpendicular to the [0001]. When a stress was applied in the [0001] direction of the ZnO single crystal, the rectification and photovoltaic effects are abated and disappeared. The disappearance of the two effects results from the pressure-induced disappearance of the polar structure. The results fully demonstrated that the rectification and photovoltaic effects arise from the existence of Es in the polar [0001] direction. The Es motivates the directional transfer of the electrons and photocreated charges along the [0001] direction, and the rectification and photovoltaic effects are thus observed. These results provide direct evidence for the polar structure theory and suggest that the polar structures can be employed to develop new types of photovoltaic and other electronic and photoelectronic devices.

VPS35 promotes cell proliferation via EGFR recycling and enhances EGFR inhibitors response in gastric cancer.

BACKGROUND: Vacuolar protein sorting-associated protein 35 (VPS35) is a core component of the retromer complex which mediates intracellular protein transport. It is well known that dysfunctional VPS35 functions in the accumulation of pathogenic proteins. In our previous study, VPS35 was found to be a potential gene related to poor prognosis in gastric cancer. However, the biological functions of VPS35 in gastric cancer remain unclear. METHODS: Cell viability assays were performed to examine whether VPS35 affected cell proliferation. Immunoprecipitation and biotin assays showed that VPS35 bound to epidermal growth factor receptor (EGFR) in the cytoplasm and recycled it to the cell surface. Patient-derived xenografts and organoids were used to evaluate the effect of VPS35 on the response of gastric cancer to EGFR inhibitors. FINDINGS: VPS35 expression levels were upregulated in tumour tissues and correlated with local tumour invasion and poor survival in patients with gastric cancer. VPS35 promoted cell proliferation and increased tumour growth. Mechanistically, VPS35 selectively bound to endocytosed EGFR in early endosomes and recycled it back to the cell surface, leading to the downstream activation of the ERK1/2 pathway. We also found that high VPS35 expression levels increased the sensitivity of the xenograft and organoid models to EGFR inhibitors. INTERPRETATION: VPS35 promotes cell proliferation by recycling EGFR to the cell surface, amplifying the network of receptor trafficking. VPS35 expression levels are positively correlated with gastric cancer sensitivity to EGFR inhibitors, which offers a potential method to stratify patients for EGFR inhibitor utilisation. FUNDING: National Natural Science Foundation of China.

Hormesis Responses of Growth and Photosynthetic Characteristics in Lonicera japonica Thunb. to Cadmium Stress: Whether Electric Field Can Improve or Not?

"Hormesis" is considered a dose-response phenomenon mainly observed at hyperaccumulator plants under heavy metals stress. In this study, the effects of electric fields on hormesis responses in Lonicera japonica Thunb. under cadmium (Cd) treatments were investigated by assessing the plant growth and photosynthetic characteristics. Under Cd treatments without electric fields, the parameters of plant growth and photosynthetic characteristics increased significantly when exposed to 5 mg L-1 Cd, and decreased slightly when exposed to 25 mg L-1 Cd, showing an inverted U-shaped trend, which confirmed that low concentration Cd has a hormesis effect on L. japonica. Under electric fields, different voltages significantly promoted the inverted U-shaped trend of the hormesis effect on the plant, especially by 2 V cm-1 voltage. Under 2 V cm-1 voltage, the dry weight of the root and leaf biomass exposed to 5 mg L-1 Cd increased significantly by 38.38% and 42.14%, and the photosynthetic pigment contents and photosynthetic parameters were also increased significantly relative to the control, indicating that a suitable electric field provides better improvements for the hormesis responses of the plant under Cd treatments. The synergistic benefits of the 5 mg L-1 Cd and 2 V cm-1 electric field in terms of the enhanced hormesis responses of growth and photosynthetic characteristics could contribute to the promoted application of electro-phytotechnology.

Unraveling the Strong Fluorescence Enhancement of HPBI Molecules by ZIF-8 Colloidal Suspensions via Adsorption Analysis.

Enhancing the fluorescence of organic dye by colloidal particles is one of the most promising routes to optimize fluorescence detection. However, in addition to metallic particles, which serve as the most frequently used particles and have been found to employ the plasmonic resonance to provide strong fluorescence enhancement, neither new types of colloidal particles nor new fluorescence mechanisms have been intensively explored in recent years. In this work, strongly enhanced fluorescence was observed when 2-(2-hydroxyphenyl)-1H-benzimidazole (HPBI) molecules were simply mixed with zeolitic imidazolate framework-8 (ZIF-8) colloidal suspensions. Moreover, the enhancement factor ΔI = IHPBI+ZIF-8/IHPBI does not increase accordingly with the increasing amount of HPBI. To find out how the strong fluorescence was triggered and affected by the amount of HPBI, multiple techniques were applied to analyze the adsorption behavior. By combining analytical ultracentrifugation with first-principles calculations, we proposed that HPBI molecules were adsorbed onto the surface of ZIF-8 particles coordinatively and electrostatically, depending on the concentration of HPBI molecules. The coordinative adsorption would result in a new kind of fluorescence emitter. The new fluorescence emitters tend to distribute on the outer surface of ZIF-8 particles periodically. The distance between each fluorescence emitter is fixed and much smaller than the wavelength of the excitation light. Thus, it can be concluded that collective spontaneous emission might be triggered.

Large-Scale Ultra-Robust MoS2 Patterns Directly Synthesized on Polymer Substrate for Flexible Sensing Electronics.

Synthesis of large-area patterned MoS2 is considered the principle base for realizing high-performance MoS2 -based flexible electronic devices. Patterning and transferring MoS2 films to target flexible substrates, however, require conventional multi-step photolithography patterning and transferring process, despite tremendous progress in the facilitation of practical applications. Herein, an approach to directly synthesize large-scale MoS2 patterns that combines inkjet printing and thermal annealing is reported. An optimal precursor ink is prepared that can deposit arbitrary patterns on polyimide films. By introducing a gas atmosphere of argon/hydrogen (Ar/H2 ), thermal treatment at 350 °C enables an in situ decomposition and crystallization in the patterned precursors and, consequently, results in the formation of MoS2 . Without complicated processes, patterned MoS2 is obtained directly on polymer substrate, exhibiting superior mechanical flexibility and durability (≈2% variation in resistance over 10,000 bending cycles), as well as excellent chemical stability, which is attributed to the generated continuous and thin microstructures, as well as their strong adhesion with the substrate. As a step further, this approach is employed to manufacture various flexible sensing devices that are insensitive to body motions and moisture, including temperature sensors and biopotential sensing systems for real-time, continuously monitoring skin temperature, electrocardiography, and electromyography signals.

Characterization of the Complete Chloroplast Genome and Phylogenetic Implications of Euonymus microcarpus (Oliv.) Sprague.

Euonymus microcarpus (Oliv.) Sprague, is a species of evergreen shrub of the genus Euonymus, family Celastraceae. Here, we extracted the genomic DNA from the leaves of E. microcarpus and constructed a paired-end library. The chloroplast genome of E. microcarpus was generated with the high-throughput sequencing by the illumina Hiseq X Ten platform and de novo assembly. The chloroplast genome had a quadripartite structure, containing a long single copy region with a size of 85,386 bp and a short single copy region with a size of 18,456 bp, separated by two inverted repeat regions of 26,850 bp. The chloroplast genome contained 133 genes identified in total, including 87 potential protein-coding genes, 38 transfer RNA genes, and eight ribosomal RNA genes. A total of 282 simple sequence repeats and 63 long repeats were found. Furthermore, the phylogenetic relationships inferred that E. microcarpus is sister to E. japonicus and E. schensianus. A comparison of the structure of the chloroplast genomes of eight Euonymus species suggests a nucleotide variability of the junction sites and a higher divergence of non-coding regions, compared to the coding regions. The original findings of the study serves as a good reference for chloroplast genome assembly and a valuable foundation for the genetic diversity and evolution of E. microcarpus.

Iron-catalyzed regioselective synthesis of (E)-vinyl sulfones mediated by unprotected hydroxylamines.

An Fe-catalyzed unprotected hydroxylamine mediated Heck-type coupling between sulfinic acids and alkenes for the regioselective synthesis of (E)-vinyl sulfones has been developed. Mechanism studies indicated for the first time that a radical process may be involved and that hydroxylamines play multiple roles, including those of a mild oxidant and an in situ base. It was found for the first time that this transformation not only realizes C-S bond construction promoted by unprotected hydroxylamines, but also provides a practical and complementary method for the preparation of structurally important (E)-vinyl sulfones.

Prognostic values of clinical and molecular features in HER2 low-breast cancer with hormonal receptor overexpression: features of HER2-low breast cancer.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) low breast cancer was considered as a distinct subtype different from HER2-zero breast cancer. Our study aimed to investigate the prognostic values of clinicopathological features and recurrence score (RS) in HER2-low and HER2-zero hormone receptor (HR)-positive breast cancer patients. METHODS: A total of 2099 HR + primary female breast cancer patients diagnosed between Jan 2009 and Jan 2019 were collected. Tumors with immunohistochemistry 1 + /2 + and negative in situ hybridization results were defined as HER2-low. We compared the clinical and genetical features of HER2-low (n = 1732) and HER2-zero (n = 367) breast cancer and their prognostic values. RESULTS: Estrogen receptor (ER) high expression (> 90%) was more common in HER2-low breast cancer than HER2-zero breast cancer (78.2% vs 58.6%, p < 0.01). Five-year disease-free survival (DFS) was similar between HER2-zero and HER2-low subgroups (92.3% vs 93.3%, p = 0.83). The predictive value of RS was only significant in HER2-zero patients (p = 0.03). The proliferation-related genes performed well in predicting DFS in HER2-zero patients, but not in HER2-low patients (p for interaction < 0.01). The higher HER2 module score was correlated with worse DFS only in HER2-low patients (p = 0.04). CONCLUSION: We observed similar survival outcomes between HER2-low and HER2-zero HR + patients. HER2-low patients had a higher proportion of ER high expressed tumors than HER2-zero patients did. RS and its proliferation module might be less clinically meaningful to HER2-low patients.

Electric Field-Enhanced Cadmium Accumulation and Photosynthesis in a Woody Ornamental Hyperaccumulator-Lonicera japonica Thunb.

The multi-system of electro-phytotechnology using a woody ornamental cadmium (Cd) hyperaccumulator (Lonicera japonica Thunb.) is a new departure for environmental remediation. The effects of four electric field conditions on Cd accumulation, growth, and photosynthesis of L. japonica under four Cd treatments were investigated. Under 25 and 50 mg L-1 Cd treatments, Cd accumulation in L. japonica was enhanced significantly compared to the control and reached 1110.79 mg kg-1 in root and 428.67 mg kg-1 in shoots influenced by the electric field, especially at 2 V cm-1, and with higher bioaccumulation coefficient (BC), translocation factor (TF), removal efficiency (RE), and the maximum Cd uptake, indicating that 2 V cm-1 voltage may be the most suitable electric field for consolidating Cd-hyperaccumulator ability. It is accompanied by increased root and shoots biomass and photosynthetic parameters through the electric field effect. These results show that a suitable electric field may improve the growth, hyperaccumulation, and photosynthetic ability of L.japonica. Meanwhile, low Cd supply (5 mg L-1) and medium voltage (2 V cm-1) improved plant growth and photosynthetic capacity, conducive to the practical application to a plant facing low concentration Cd contamination in the real environment.

Tuning luminescence of the fluorescent molecule 2-(2-hydroxyphenyl)-1H-benzimidazole via zeolitic imidazolate framework-8.

Zeolitic imidazolate framework-8 (ZIF-8) is one of the most promising metal-organic frameworks because of its excellent high porosity, stability and geometrically well-defined structure. However, the application of ZIF-8 in the field of fluorescent molecular sensing has not been intensively explored. Our work demonstrates the versatility of ZIF-8 as a carrier material, which can be used for small molecule [2-(2-hydroxyphenyl)-1H-benzimidazole (HPBI)] capture and fluorescence enhancement. ZIF-8 displays luminescent behavior changes when combined with HPBI, as the emission peaks of ZIF-8 and HPBI are located in the same range for resonance enhancement of fluorescence. The results of the experiment indicate that the fluorescence enhancement effect will change in the presence of different concentrations of HPBI. We propose that the pore structure of ZIF-8 could provide an opportunity for the adsorption of HPBI molecules, and eventually the adsorption would saturate. The high porosity of ZIF-8 provides the path to HPBI aggregation or entrance into the ZIF-8 internal structure. Our results suggest that ZIF-8 may offer great promise for molecular fluorescence sensing.