A water quality assessment model involving novel fluorescence technology.

The reasonable utilization of water resources and real-time monitoring of water pollution are the core tasks of current world hydrological and water conservancy work. Novel technologies and methods for monitoring water pollution are important means to ensure water health. However, the absence of intuitive and simple analysis methods for the assessment of regional pollution in large-scale water bodies has prevented scientists from quickly grasping the overall situation of water pollution. In this study, we propose a strategy based on the unique combination of fluorescence technology and simple kriging (SK) interpolation (FL-SK) for the first time. This strategy could present the relative magnitude and distribution of the physicochemical indicators of a whole natural lake intuitively and accurately. The unique FL-SK model firstly offers a simple and effective water quality method that provides the pollution index of different sampling points in lakes. The macroscopic evaluation of large-scale water bodies by the FL-SK model primarily relies on the fluorescence response of the RDM-TPE to the comprehensive indicators of the water body, as experimental results have revealed a good correlation between fluorescent responses and six normalized physicochemical indicators. Multiple linear regression and fluorescence response experiments on RDM-TPE indicate that to some extent, the fluorescence signals of the FL-SK model may originate from a certain type of sulfide in the water body. Pattern discovery could enable the analysis of pollution levels in other ecosystems and promote early pollution assessment in the future.

Introducing fluorescent probe technology for detecting microcystin-LR in the water and cells.

BACKGROUND: For a long time, the environment hazards caused by cyanobacteria bloom and associated microcystins have attracted attention worldwide. Microcystin-LR (MC-LR) is the most widely distributed and most toxic toxin. At present, numerous MC-LR detection methods exist many drawbacks. Therefore, a quick and accurate method for identifying and detecting MC-LR is crucial and necessary. In this work, we strived to introduce a novel fluorescence assay to detect MC-LR in the water and cells. RESULTS: According to the special spatial configuration and physicochemical properties of MC-LR, we designed and constructed six fluorescent probes. The design concepts of the probes were exhaustively elaborated. MC-YdTPA, MC-YdTPE, MC-RdTPA, and MC-RdTPE could show significant fluorescence enhancement in MC-LR solution. Significantly, MC-YdTPA, MC-YdTPE, and MC-RdTPA could also response well in the cells treated with MC-LR, demonstrating these fluorescent probes' values. The recognition mechanism between probes and MC-LR were also deeply explored: (1) The polyphenylene ring structure of probes may have nested or hydrogen bond weak interaction with the ring structure of MC-LR. (2) The probes can generate a reaction to the hydrogen ions ionized by MC-LR. SIGNIFICANCE: We proposed the novel ideas for designing MC-LR probes. This research can provide valuable experiences and important assistance in synthesizing MC-LR fluorescent probes. We expect that this work may bring new ideas to develop fluorescent probes for researching MC-LR in vivo and in vitro.

Feedback of lake trophic status via MC-LR fluorescence technique.

Eutrophication remains one of the most challenging environmental problems, and microcystin-leucine-arginine (MC-LR) produced in eutrophic waters would cause serious ecological risks. However, the traditional assessment methods of trophic status, such as water quality index (WQI) and trophic status index (TSI), could not directly reflect the existence or concentration of MC-LR in water. Moreover, traditional MC-LR detection methods are costly and time-consuming. Therefore, it remains a challenge to develop a method that can simply and quickly reflect the level of MC-LR. Herein, a novel probe with specific response to MC-LR was proposed to assess the distribution characteristics of MC-LR in water bodies. By combining the response signal of the probe with the filtered water sample and the water quality parameters, a more accurate assessment tool for MC-LR was obtained. This probe can specifically respond to MC-LR in aqueous solution, and its fluorescence signal is enhanced with the increase of MC-LR concentration. More importantly, the fluorescent signal of the probe showed a significant positive correlation with MC-LR concentration in water samples. This visualization tool has practical application potential for the preliminary assessment of MC-LR in eutrophic waters.

Visualization Tools for Detecting Microcystin-LR in the Biological System via Near-Infrared Fluorescent Probes.

Numerous toxicological and epidemiological studies have shown that microcystin-LR (MC-LR) could cause a variety of toxicity to humans and animals. However, the absence of effective methods to trace MC-LR in biological systems has hindered the in-depth understanding of the mechanism of MC-LR toxicity. Near-infrared (NIR) fluorescent probes are crucial tools for accurate visualization and in-depth study of specific molecules in biological systems. Due to the lack of effective design strategies, NIR fluorescent probes for imaging MC-LR specifically in biological systems have not been reported yet. In order to address this pressing issue, herein, we have introduced a new and facile strategy to improve MC-LR detection and imaging in biological systems, and based on this design strategy, three NIR fluorescence probes (MC-RdTPA1, MC-RdTPA2, and MC-RdTPE1) have been constructed. These probes have several advantages: (i) have long emission wavelength and large Stokes shifts, which have great potential in vivo imaging applications; (ii) could selectively visualize MC-LR in cells; and (iii) showed stable fluorescence intensity in the pH range of 5.0-7.0. This work may provide a new avenue for the detection of MC-LR in biological systems and new tool to advance our knowledge of the mechanism of MC-LR toxicity.

Immunoassay technology: Research progress in microcystin-LR detection in water samples.

Increasing global warming and eutrophication have led to frequent outbreaks of cyanobacteria blooms in freshwater. Cyanobacteria blooms cause the death of aquatic and terrestrial organisms and have attracted considerable attention since the 19th century. Microcystin-LR (MC-LR) is one of the most typical cyanobacterial toxins. Therefore, the fast, sensitive, and accurate determination of MC-LR plays an important role in the health of humans and animals. Immunoassay refers to a method that uses the principle of immunology to determine the content of the tested substance in a sample using the tested substance as an antigen or antibody. In analytical applications, the immunoassay technology could use the specific recognition of antibodies for MC-LR detection. In this review, we firstly highlight the immunoassay detection of MC-LR over the past two decades, including classical enzyme-link immunosorbent assay (ELISA), modern immunoassay with optical signal, and modern immunoassay with electrical signal. Among these detection methods, the water environment was used as the main detection system. The advantages and disadvantages of the different detection methods were compared and analyzed, and the principles and applications of immunoassays in water samples were elaborated. Furthermore, the current challenges and developmental trends in immunoassay were systematically introduced to enhance MC-LR detection performance, and some critical points were given to deal with current challenges. This review provides novel insight into MC-LR detection based on immunoassay method.