Academician Tang benzhong team of Hong Kong University of science and technology: starting from aggregation induced luminescence silver ion probe, fluorescent silver staining and dynamic monitoring of silver ion release

In recent years, the research and application of aggregation induced luminescence have been developing rapidly Among them, "dissolution does not light up, aggregation light up", the application of this strong fluorescence property transformation has become a mature and reliable design idea in the field of chemical sensors, thus developing a series of fluorescence probes, which can detect various small molecules (such as CO2) with high sensitivity , monosaccharide, ammonia from putrefaction, ion, biological macromolecule (such as urinary protein, cardiolipin) and microorganism (such as bacteria, fungi, viruses, algae), etc Silver ion detection has an important application prospect, because silver ion has a high selective affinity for biomolecules The silver staining technology developed on this basis is a classic method to detect and analyze biological structures (including proteins, nucleic acids, tissue sections) in the laboratory In addition, silver materials are highly effective antibacterial materials, especially nano silver materials, which have been widely used in fresh food packaging, medical equipment anti pollution and wastewater treatment The bactericidal function of silver is considered to be related to the concentration of silver ions released The release process of silver ions can help to analyze and study the real bactericidal mechanism and potential of silver materials, and is of great significance to analyze the biological and environmental toxicity of silver materials Recently, academician Tang benzhong of Hong Kong University of science and Technology (HKUST) and his collaborators have made new breakthroughs in silver ion detection and related applications Review of previous reports by academician Tang benzhong research group: academician Tang benzhong team of Hong Kong University of science and technology: aggregation induced emission, Aie research group of academician Tang benzhong of Hong Kong University of science and technology: brief introduction of academician Tang benzhong who prepared non-traditional light-emitting small heterocyclic polymer by simple multi-component polymerization Frontier achievements: silver ion detection system and its application theory and design based on the principle of aggregation induced luminescence: in recent years, the report of AIE silver ion probe designed by the phenomenon of aggregation induced luminescence (AIE) is not rare In this series of work, the classical tetrastyrene was used as the fluorescent chromogenic nucleus of AIE, and the Tetrazolate anion was used as the high affinity target group to guide the aggregation of silver ions Compared with other silver ion probes, the structure advantage of tpe-4ta is that it can retain four negative charges, so it can be highly dissolved in the water phase The special precipitation reaction of Tetrazolate anion silver ion has been found in the 19th century, and has been studied in the 1950s It is rarely mentioned in the research of organometallic polymers in recent years It is generally believed that the insoluble structure is a polymer with metal organic molecules connected by coordination Figure 1 Design of aggregation induced luminescence silver ion probe (source: angelw Chem Int ed., DOI: 10.1002/anie.201801653) The characterization of aggregation induced luminescence detection process is as described above Silver ion recognition is an AIE process When the AIE probe is dissolved in water, it is in a dark state and can't be stimulated to emit light; after the silver ion is added, it can be assembled into a nanostructure with the AIE probe (Fig 2, C and D), and excited by 375 nm light to emit green light (Fig 2, a and b) It is found that the detection limit of the system for silver ions reaches the level of nanomolar In addition, the detection performance is stable: 1 Almost no response of other cations (Fig 2, e); 2 Response is stable in pH 5-12 environment (Fig 2, f) Figure 2 Characterization of the aggregation induced luminescence silver ion recognition process (source: angelw Chem Int ed.), DOI: 10.1002/anie.201801653) application: fluorescence silver staining technology Silver-AIE protein staining silver staining is a classic method for identifying proteins and nucleic acids and other biomolecules after gel electrophoresis separation in laboratory It is commonly used for analysis and identification of one-dimensional and two-dimensional protein adhesives (Fig 3) Traditional silver staining consists of two main steps: 1 Selective binding of silver ions to biomolecules; 2 In situ reduction of silver ions to dark metallic silver nanoparticles, followed by protein labeling Because the color reaction of reducing silver is difficult to control, in the actual use process, silver staining faces several problems: low repeatability, unable to quantify protein content, strong background, often need sensitizer (such as glutaraldehyde) and subsequent mass spectrometry analysis failure In this paper, silver ion specific aggregation induced luminescence is used to replace the traditional silver reduction process (silver particle generation) (Fig 3), which greatly avoids the defects of traditional silver staining, which is a new silver staining method Figure 3 Example of traditional silver staining (upper part), principle (lower left) and fluorescent silver staining scheme (lower right) (source: angel Chem Int ed., DOI: 10.1002/anie.201801653) Referring to traditional silver nitrate staining, silver AIE staining technology is developed in this paper As shown in Figure 4A below, this technique is simple: after electrophoresis separation and acetic acid fixation, dip the glue into AgNO 3 solution first After simple cleaning, immerse in AIE solution After simple cleaning again, it can be displayed under the UV light (Fig 4B and Fig 4C SYPRO Ruby staining results comparison) Figure 4 Silver AIE staining process and effect (source: angelw Chem Int ed.), Doi: 10.1002/anie.201801653) using a protein library containing 14 different molecular weights, the author compared the silver AIE staining with the traditional silver nitrate staining and the commonly used SYPRO Ruby fluorescent staining found that silver AIE staining showed excellent properties in the background (Fig 5a), detection lower limit (Fig 5b), band outline display (Fig 5C), whole protein molecular overall induction efficiency (Fig 5d) and protein quantitative analysis (Fig 5e) Especially as a silver staining technique, the silver AIE staining shows linear properties in a very wide concentration range (Fig 5e), which is suitable for one-dimensional gel quantitative analysis and two-dimensional gel quantitative / comparative analysis Figure 5 Comparative study of three protein staining methods (source: angelw Chem Int ed.), Doi: 10.1002/anie.201801653) application II: monitoring of silver ion release process due to its excellent broad-spectrum bactericidal performance, silver materials, especially nano silver, have become a very important class of antibacterial and bactericidal materials in medical devices, fresh food packaging and wastewater treatment In addition, as heavy metal materials, silver also affects microbial life and brings environmental toxicity after entering the natural environment The silver ions released from silver nanomaterials are considered to be the actual substances of biological effects such as nano silver sterilization Therefore, the analytical method of monitoring silver ion release is of great significance in the study and evaluation of sterilization and environmental toxicity of silver materials Monitoring the release process of silver ions from silver nanomaterials requires that the detection system can distinguish 1-valent silver ions from 0-valent metal silver nanoparticles At present, the commonly used method in the laboratory is elemental analysis and quantitative analysis (such as ICP-MS, ICP-MS) after ultrafiltration of solution silver concentration If process monitoring is needed, this method is complex, expensive and not easy to operate In this part, the tpe-4ta silver ion probe described above can easily quantify the silver ion concentration in the solution at any time (such as nanowire, left in Figure 6), and the results can be mutually verified with the analysis results obtained by ICP-MS (right in Figure 6) In addition, the AIE probe has a strong response to silver ions, but no response or weak response to silver particles and a series of other inorganic nanoparticles Figure 6 Response curve of silver ion probe in silver nanowire solution at different time points (left); time dynamics of corresponding silver concentration displayed after calibration curve (black curve: AIE fluorescence method) and control classical ICP-MS method (red curve) (source: chem.commun., DOI: 10.1039/c8cc02245c) in order to further verify the effectiveness of the new method Compared with the monitoring sensitivity, the silver nanoparticles with different surface protection and sizes were tested Table 1 summarizes the results of AIE monitoring method and ICP-MS method, and confirms the effectiveness of AIE method in the dynamic analysis of silver ion release In practical operation, AIE monitoring based on fluorescence does not need ultrafiltration separation, only needs common fluorescence analysis equipment, which is a simple, efficient and low-cost new method Table 1 Comparative analysis of silver ion release dynamics of different silver nanoparticles detected by AIE and ICP-MS (source: chem Commun., DOI: 10.1039 / c8cc02245c) summarized that starting from aggregation induced luminescence design, researchers designed a new kind of water-soluble silver ion fluorescence probe by using silver ion Tetrazolate negative ion specific precipitation response The fluorescent silver staining technology, which is suitable for the analysis of total protein components after electrophoresis gel separation, is developed by using the aggregation luminescence process, which overcomes many shortcomings of traditional silver staining In addition, the probe can be used to analyze the release process of silver ions from various nanomaterials, which is simple, efficient and can be verified with the results of the classical ICP-MS method The results of fluorescent silver staining technology applied to protein gel analysis were published in Angew Chem Chem on the topic of "Fluorogenic Ag + - Tetrazolate Aggregation EnablesEfficient Fluorescent Biological Silver Staining" The writer is Chen Sijie, Professor Tang Benzhong and Dr Liu Mingwei, rehabilitation medical center Alex Y H Wong, Ryan T K Kwok, Ying Li, Huifang Su,Jacky W Y Lam, Sijie Chen,* and Ben Zhong Tang* ）。 The results of detecting the dynamic release of silver ions from nano silver materials by AIE probe were recently published on chem Commission with the title of "real-time monitoring of the solution kinetics of silver nanoparticles and nanowires in aquaticenvironments using an aggregation induced emission Fluogen" Professor Wang Wenxiong (author: Neng Yan, Sheng Xie, Ben Zhong Tang *, Wen Xiong Wang *) Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeango app, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.