Naphthalimide-rhodamine based fluorescent probe for ratiometric sensing of cellular pH

The pH values of lysosomes in cancer cells is slightly lower than that in normal cells, which can be used to distinguish cancer cells from normal cells. According to this, a naphthalimide-rhodamine based fluorescent probe（hereafter referred to as RBN） with a pK_a of 4.20 was designed and synthesized for ratiometric sensing of cellular pH via fluorescence resonance energy transfer（FRET）, which can respond to different pH precisely through ratiometric fluorescence intensity（Ⅰ_（577）/Ⅰ_（540））. RBN can be employed to distinguish cancer cells from normal cells on the basis of different fluorescent response, in particular, RBN showed excellent water solubility and low cell toxicity, all these are quite significant for potential application in cancer diagnose and therapy.

Semisynthesis of new ethers from furyl-ring-based acylation derivatives of fraxinellone as insecticidal agents against Mythimna separata Walker in vivo

Fraxinellone, a naturally occurring degraded limonoid, is mainly isolated from Dictamnus dasycarpus and Melia azedarach. In continuation of our program aimed at the discovery of plant natural products-based insecticidal agents, twenty-two new ethers from furyl-ring-based acylation derivatives were prepared by structural modifications of fraxinellone. Their insecticidal activity was evaluated against the pre-thirdinstar larvae of Mythimna separata Walker in vivo. Among them, compounds 5 e and 5 j exhibited more potent insecticidal activity than toosendanin with the final mortality rates greater than 60%. Their structure-activity relationships were also discussed.

Fluorescent probes for recognition of ATP

Adenosine 5＇-triphosphate（ATP） not only participates in various physiological activities as the universal energy currency but also implicates in various pathological processes in living cells. Consequently,sensitive and selective detection ATP in live cells, tissues, as well as environmental samples, are urgently demanded. Due to the simple and convenient operation, economy cost, high selectivity for analyte, well biocompatibility and low cytotoxicity, fluorescent sensors for monitoring ATP have aroused great attention of researchers. In recent years, a large number of fluorescent sensors for detecting ATP have developed. This manuscript summarized most of these sensors and the interaction-mechanism between ATP and sensors, mainly including electrostatic interaction, p-p interaction, covalent bonding or hydrogen bond, or combinations of them, and the advantages of each strategy were also generalized.Here, a viewpoint of classification was shown where the sensors were divided into five typed ones according to the structure of probes used.

Virtual special issue:Supramolecular/macrocyclic chemistry

Welcome to this virtual special issue, which focuses on supramolecular/macrocyclic Chemistry. The beginnings of supramolecular chemistry can be traced back to 1967 with the identification of crown ethers by Pedersen [1], and being acknowledgement by the 1987 Nobel Prize to Lehn, Cram, and Pedersen for their leading discoveries in the host-guest systems [2]. Since these