Min Shen,Tingting Pan,Yonghao Chen,Juewei Ning,Fengyu Su,Yanqing Tian
Ammonium ions (NH4+) are one of the important metabolic products and are closely related to human health. Currently, many NH4+ detection methods are inevitably disturbed by amino acids, K+, or other substituted amines (such as trimethylamine). To alleviate this problem, a new sensor was designed in this study, which consisted of the fluorescent indicator KS, hydrogel medium D4, and a hydrophobic membrane. In this sensing system, NH4+ and NH3 coexisted in equilibrium; NH3 could pass through a suitable hydrophobic film and transform into NH4+, which complexed with KS, resulting in a change of the probe's fluorescence intensity. By adjusting the internal composition of the sensing matrix, an excellent NH4+ sensor NS-1 was obtained; it demonstrated effective detection of NH4+ in the range 0.3–15.6 mM with a limit of detection (LOD) of 258 μM, and it was not disturbed by K+ or other substituting amines.
Da Luo,Yi Zhang,Minyu Wang,Chen Zhu,Yue Yao,Weifeng Yao,Li Zhang,Fang-Fang Cheng
Nanoparticles are often used to serve as drug delivery systems to improve the therapeutic efficacy of some hydrophobic drugs. In this work, PEG and peptide-modified titanium phosphate nanoparticles (TiP–PEG/peptide) were synthesized to enhance the drug delivery efficacy of tirucalla-8,24-diene-3β,11β-diol-7-one (KS-01), a major bioactive and hydrophobic component extracted from Euphorbia kansui. This drug delivery system with a loading efficiency of about 29.8 mg KS-01/1 g TiP–PEG/peptide exerted a significantly lower cell viability rate of MCF-7 than free KS-01, indicating that these carriers can effectively increase the therapeutic efficacy by improving its water solubility. Moreover, according to the fluorescence intensity of FAM which can be generated by caspase-3 cleaving DEVD-embedded peptide, the caspase-3 level could be determined and the therapeutic efficacy could be visualized in real time.
Min Shen,Tingting Pan,Juewei Ning,Fangyuan Sun,Mengyu Deng,Jianxiang Liao,Fengyu Su,Yanqing Tian
The concentration of potassium ion is an important indicator for human health, and its abnormality is often accompanied by various diseases. However, most tools currently used to study potassium ion transport are low throughput. Herein, we reported a new K + fluorescent nanoprobe CP1-KS with high selectivity and sensitivity to K + (fluorescence enhanced factor was up to 9.91 at 20 mM K + ). The polymeric fluorescent probe CP1-KS was composed of the small-molecular K + indicator KS and amphiphilic copolymer CP1. This sensor can be easily and uniformly dispersed in cell culture medium and is suitable for high throughput analysis. To assess the utility of the probe CP1-KS in biological field, this probe was employed as an extracellular fluorescent probe to monitor the efflux of K + from cells ( E coli , B. Subtilis 168, Hela and MCF-7 cells) under various stimulation including lysozyme, nigericin, digitonin, and ATP. Results demonstrated that CP1-KS is an effective analysis tool for extracellular K + concentration. We believe that the nanoprobe has great potential in antibacterial drug screening, K + ionophore function, K + channel activity, cell membrane permeability analysis or other K + related field in the future.
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