A new phenothiazine‐based fluorescence sensor for imaging Hg 2+ in living cells

Phenothiazine-Based Cu(II)-Selective Fluorescent Sensor: GHK-Cu Sensing Applications

Sensing important metals in different environments is an important area and involves the development of a wide variety of metal-sensing materials. The employment of fluorescent sensors in metal sensing has been one of the most widely applied methodologies, and the identification of selective metal sensors is important. We herein report a phenothiazine-based Cu(II) fluorescent sensor that is highly selective to Cu(II) ions compared with other transition metal salts. The Lewis acidity of the Cu(II) salt certainly was found to be a factor for obtaining an enhanced sensing response in MeOH as the solvent, while a ratio of 1:1 was calculated to be the most optimum for getting the desired response.

Recent development of small-molecule fluorescent probes based on phenothiazine and its derivates

Fluorescence probes, as analytical tools with the ability to perform rapid and sensitive detection of target analytes, have made outstanding contributions to environmental analysis and bioassays. Considering the expanding developments in these areas, fluorophores play a key role in the de-sign of fluorescence probes. Compared to classical fluorophores, phenothiazines with elec-tron-rich characteristics have been widely applied to construct electron donor-acceptor dyes, which exhibit outstanding performance in both fluorimetric and colorimetric analysis. In addition, these probes also exhibit the pronounced ability in both solution and solid-state, achieving portable detection for environmental analysis. In this review, we summarize recent advances in the performance of phenothiazine-based fluorescent probes for detecting various analytes, especially in cations, anions, ROS/RSS, enzyme and other small molecules. The general design rules, response mechanisms and practical applications of the probes are analyzed, followed by a discussion of exiting challenges and future research perspectives. It is hoped that this review will provide a few strategies for the development of phenothiazine-based fluorescent probes.

Coordination-driven reversible supramolecular assembly formation at biological pH: Trace-level detection of Hg2+ and I- ions in real life samples

Pyridine coupled bisbenzimidazole probe has been developed for colorimetric sensing of heavy metal pollutants in the aqueous medium. Mechanistic investigation indicates that Hg²⁺ ions (detection limit: 7.5 ppb) bind to the pyridyl nitrogen ends and form linear supramolecular assembly. Red-shifted absorption and fluorescence maxima upon addition of Hg²⁺ ions were observed, presumably caused by charge transfer interaction and coordination-driven planarization of the biphenyl backbone. Additionally, the in-situ formed mercury complex was utilized for selective recognition of iodide ion (detection limit: 20.2 ppb). Considering its high sensitivity, the present system was utilized in analysing Hg²⁺ in natural water and in presence of albumin protein. The high recovery values ranging from 95 to 98% with substantially low relative standard deviation (<4%) confirm the suitability of the present method in estimating trace-level of Hg²⁺ even in real-life samples. Imaging of intracellular Hg²⁺ ion was also achieved in cervical cancer cells. Low-cost paper strips are designed for rapid, on-site detection of Hg²⁺ without engaging any sophisticated analytical tools or trained personnel.

Mercury Toxicity and Detection Using Chromo-Fluorogenic Chemosensors

Mercury (Hg), this non-essential heavy metal released from both industrial and natural sources entered into living bodies, and cause grievous detrimental effects to the human health and ecosystem. The monitoring of Hg2+ excessive accumulation can be beneficial to fight against the risk associated with mercury toxicity to living systems. Therefore, there is an emergent need of novel and facile analytical approaches for the monitoring of mercury levels in various environmental, industrial, and biological samples. The chromo-fluorogenic chemosensors possess the attractive analytical parameters of low-cost, enhanced detection ability with high sensitivity, simplicity, rapid on-site monitoring ability, etc. This review was narrated to summarize the mercuric ion selective chromo-fluorogenic chemosensors reported in the year 2020. The design of sensors, mechanisms, fluorophores used, analytical performance, etc. are summarized and discussed.