Min Zhang

Aqueous two-phase extraction (ATPE) is widely used for the chirality-selective separation of single-walled carbon nanotubes (SWCNTs). In the conventional normal-phase (NP) ATPE mode, larger-diameter species are extracted first, whereas later-eluting small-diameter SWCNTs often suffer from pronounced peak broadening, interfacial trapping losses and insufficient resolution from adjacent species, thereby limiting separation efficiency, purity, and overall resolving power. To address this limitation, we introduce a reversed-phase (RP) ATPE mode that inverts the transfer sequence. In this configuration, SWCNTs are initially loaded into the hydrophobic PEG-rich upper phase with sodium dodecyl sulfate and are subsequently transferred into the hydrophilic Dex-rich lower phase by modulation with sodium cholate. As a result, small-diameter species are selectively extracted first. Through a side-by-side comparison of NP and RP modes, we show that RP-ATPE provides improved separation of small-diameter (n,m) species, such as (6,4) and (7,3), by affording narrower peak widths, higher resolution, higher purity for several species, and fewer sequential fractionation steps, whereas NP-ATPE remains more effective for larger-diameter species. To rationalize this diameter-dependent performance inversion and predict effective separation windows, we established an empirical relationship between surfactant concentration and partition coefficient based on Hill-type fitting. On this basis, a graphical selection map was constructed to guide mode selection and surfactant optimization according to target nanotube diameter. Rather than introducing a fundamentally new separation chemistry, this work establishes a systematic comparative framework and a practical mode-selection strategy, advancing ATPE toward a more rational, predictive, and operationally efficient platform for chirality-resolved isolation of SWCNTs.

Lonicerae japonicae Flos ( LjF , honeysuckle) is a major component of beverages and healthcare products, as well as a key botanical resource in traditional Chinese medicine. Chlorogenic acids (CGAs) are the main bioactive components of LjF , possessing antioxidant, anti‐inflammatory, antiviral, and other biological activities, among which CGA serves as the key marker compound for LjF quality evaluation. In the present work, LjF samples were subjected to controlled dry heating and analyzed by LC‐DAD and UPLC‐QTOF‐MS. Progressive degradation of neochlorogenic acid, cryptochlorogenic acid, and isochlorogenic acid A was accompanied by concomitant accumulation of CGA, isochlorogenic acid B, and isochlorogenic acid C. Furthermore, the effects of temperature and time on thermal transformation, along with key chemical markers for different heat treatment conditions were clarified via principal component analysis of chemical changes. Mechanistic investigations revealed that isochlorogenic acid A undergoes competitive cleavage of the C‐3 or C‐5 caffeoyl ester bond to yield neochlorogenic acid (kinetic product) or CGA (thermodynamic product), followed by intramolecular acyl migration to form isochlorogenic acid B and isochlorogenic acid C, with isochlorogenic acid C identified as the most stable dicaffeoyl isomer. The interconversion of monocaffeoyl isomers leads to a dynamic equilibrium, with CGA being the predominant and most stable form. These results provide the comprehensive thermal‐transformation map for CGAs in LjF and offer practical guidance for optimizing drying, roasting, and extraction protocols in the development of high‐quality LjF , an edible and medicinal homologous resource.

Exosomes are considered as potential biomarkers that can reflect information from their parent cell-associated cancer microenvironment. Recently, aptasensors have been widely used for cancer and tumor exosome detection. Aptamers related to exosome surface proteins are usually used to introduce a sequence; the aptamer is used for exosome recognition, and the introduced sequence is used to form G-quadruplexes and for signal amplification. In this paper, we found that the EpCAM aptamer is rich in guanine and unimolecular G-quadruplex with a two-layer G-tetrad under acidic conditions, and we investigated its topology, thermal stability and dissociation constant with hemin. Based on this, our proposed colorimetric aptamer sensor combines the unmodified EpCAM aptamer with hemin to construct a hemin/G-quadruplex DNAzyme and catalyze the TMB–H₂O₂ system to generate a strong colorimetric signal. Therefore, colorimetric signal changes were negatively correlated with the exosome concentration. The linear range of the 1 h assay was 10⁶–10⁸ particles per mL, and the detection limit was 3.94 × 10⁵ particles per mL. In addition, this method can detect exosomes in complex fetal bovine serum samples with good specificity and high sensitivity toward exosomes from breast, liver, and lung cancers with abnormal EpCAM protein expression.