A pH-triggered N-oxide polyzwitterionic nano-drug loaded system for the anti-tumor immunity activation research.

Triple negative breast cancer (TNBC) has the characteristics of low immune cell infiltration, high expression of tumor programmed death ligand 1 (PD-L1), and abundant cancer stem cells. Systemic toxicity of traditional chemotherapy drugs due to poor drug selectivity, and chemotherapy failure due to tumor drug resistance and other problems, so it is particularly important to find new cancer treatment strategies for TNBC with limited treatment options. Both the anti-tumor natural drugs curcumin and ginsenoside Rg3 can exert anti-tumor effects by inducing immunogenic cell death (ICD) of tumor cells, reducing PD-L1 expression, and reducing cancer stem cells. However, they have the disadvantages of poor water solubility, low bioavailability, and weak anti-tumor effect of single agents. We used vinyl ether bonds to link curcumin (Cur) with N-O type zwitterionic polymers and at the same time encapsulated ginsenoside Rg3 to obtain hyperbranched zwitterionic drug-loaded micelles OPDEA-PGED-5HA@Cur@Rg3 (PPH@CR) with pH response. In vitro cell experiments and in vivo animal experiments have proved that PPH@CR could not only promote the maturation of dendritic cells (DCs) and increase the CD4+ T cells and CD8+ T cells by inducing ICD in tumor cells but also reduce the expression of PD-L1 in tumor tissues, and reduce cancer stem cells and showed better anti-tumor effects and good biological safety compared with free double drugs, which is a promising cancer treatment strategy.

A novel fluorescent probe with aggregation induced emission (AIE) effect based on 1,4-dihydropyridine and its applications.

A fluorescent hydrazine hydrate probe (DMA) based on 1,4-dihydropyridine derivatives was designed and synthesized. The fluorescence emission peak of this probe is in the near-infrared region (667 nm), which has good selectivity to hydrazine hydrate and low detection limit (11 nM). Importantly, the probe exhibits aggregation-induced emission (AIE) characteristics. In addition, the probe is prepared with a portable test paper to realize the identification of hydrazine hydrate in the solution and the quantitative detection of hydrazine hydrate gas.

A novel ratiometric fluorescent probe for differential detection of HSO3- and ClO- and application in cell imaging and tumor recognition.

By connecting 1,8-naphthalimide and indole sulfonate, a ratio fluorescent probe capable of differential detection of hydrogen sulfite and hypochlorite was synthesized for the first time. It was able to achieve the qualitative detection of HSO3- and ClO- with high sensitivity and selectivity, respectively. It provides a multi-purpose probe and is based on different emission channels without mutual interference. The probe has the advantages of larger Stokes shift (ClO-: 115 nm, HSO3-: 88 nm), longer λem (ClO-: 515 nm, HSO3-: 548 nm) and better water solubility (DMF/PBS = 1:99, v/v). In addition, the probe is a ratio fluorescence probe, which can detect fluorescence intensity with two different emission waves. It provides internal self-calibration, reduces interference from the background and increases detection accuracy. In vitro cytotoxicity and imaging experiments show that the probe can effectively perform the detection of exogenous HSO3- and ClO- in cells. It can also achieve the detection of HSO3- and ClO- in the plasma environment. Because the probe can detect endogenous ClO-, it also has a good prospect for biological application in identifying tumor cells. Graphical abstract.

Water-soluble fluorescent probe for simultaneous detection of cyanide, hypochlorite and bisulfite at different emission wavelengths.

A fluorescent probe that responds at distinct wavelengths upon exposure to cyanide, hypochlorite, and bisulfite was synthesized. As a result, an easy to apply analytical methodology was developed for the detection of these ions. The feasibility of this method was evaluated by theoretical calculations. The probe exhibited excellent solubility in the test solution (H2O: DMF = 99: 1, v: v) with low detection limits for cyanide, hypochlorite and bisulfite (4.5 × 10 -8 M, 4.9 × 10 -7 M and 4.3 × 10 -8 M respectively) showing distinct emission wavelengths for each ion without interference in practical application. Furthermore, the probe had low toxicity and was applied for the imaging experiments of cyanide, hypochlorite and bisulfite in living HeLa and MDCK cells.

Synthesis and application of benzoxazole derivative-based fluorescent probes for naked eye recognition.

A fluorescent probe to detect biothiols (GSH/Hcy/Cys) was synthesized with benzothiazole as the fluorophore and nitromethane as the recognition group. The recognition mechanism of the fluorescent probe was deduced. It was found that a nitroalkene in the molecule was used as the recognition site for this probe and reacted with the mercapto group of the biothiols by electrophilic addition, significantly enhancing the fluorescent signal. Experimental results showed that the fluorescent probe had a low detection limit, good selectivity, strong anti-interference ability, and good naked eye recognition. The probe could detect biothiols (GSH/Hcy/Cys) in 20% organic solvent, with detection limits of 0.33 µM, 0.70 µM, and 0.87 µM, respectively. The probe will be applied further in biosensors and other fields.

An innovative near-infrared fluorescent probe with FRET effect for the continuous detection of Zn2+ and PPi with high sensitivity and selectivity, and its application in bioimaging.

As the second most abundant transition metal element in the human body, zinc ions play an important role in the normal growth and development of the human body. We have successfully synthesized a near-infrared fluorescent probe with FRET effect for the detection of Zn2+. Probe DR6G has good selectivity and anti-interference ability for Zn2+. When Zn2+ is added to the probe DR6G solution, it responds completely within seconds, releasing red fluorescence with a detection limit of 2.02 × 10-8 M. As the main product of ATP hydrolysis, PPi is indispensable in various metabolic activities in cells and the human body. Due to the strong binding ability of Zn2+ and PPi, it is easy to form ZnPPi precipitation, so we added PPi to the solution to complete the Zn2+ detection, and realized the continuous detection of PPi, and the detection limit was 2.06 × 10-8 M. Since Zn2+ and PPi play an important role in vivo, it is of great practical significance to design and synthesize a fluorescent probe that can continuously detect Zn2+ and PPi. Biological experiments have shown that the probe DR6G has low cytotoxicity and can complete the detection of exogenous Zn2+ and PPi in cells and living mice in vitro. Bacterial experiments have shown that the DR6G probe also has certain research value in the field of environmental monitoring and microbiology. Due to the constant variation of the fluorescence signals of Zn2+ and PPi during detection, we designed the logic gate program. In practical applications, the probe DR6G can quantitatively detect Zn2+ in zinc-containing oral liquids and qualitatively detect PPi in toothpaste.

Dual-modality probe nanodrug delivery systems with ROS-sensitivity for atherosclerosis diagnosis and therapy.

Most acute cardiovascular and cerebrovascular diseases are caused by atherosclerotic plaque rupture leading to blocked arteries. Targeted nanodelivery systems deliver imaging agents or drugs to target sites for diagnostic imaging or the treatment of various diseases, providing new insights for the detection and treatment of atherosclerosis. Based on the pathological characteristics of atherosclerosis, a hydrogen peroxide-sensitive bimodal probe PPIS@FC with integrated diagnosis and treatment function was designed. Bimodal probes Fe3O4@SiO2-CDs (FC) were prepared by coupling superparamagnetic iron oxide and carbon quantum dots synthesized with citric acid, and self-assembled with hydrogen peroxide stimulus-responsive amphiphilic block polymer PGMA-PEG modified with simvastatin (Sim) and target molecule ISO-1 to obtain drug-loaded micelles PGMA-PEG-ISO-1-Sim@FC (PPIS@FC). PPIS@FC could release Sim and FC in an H2O2-triggered manner, achieving the goal of releasing drugs using the special microenvironment at the plaque. At the same time, in vivo magnetic resonance and fluorescence imaging results proved that PPIS@FC possessed targeting ability, magnetic resonance imaging and fluorescence imaging effects. The results of the FeCl3 and ApoE-/- model showed that PPIS@FC had an excellent therapeutic effect and in vivo safety. Therefore, dual-modality imaging drug delivery systems with ROS response will become a promising strategy for the diagnosis and treatment of atherosclerosis.

An innovative fluorescent probe based on dicyanoisoflurone derivatives for differential detection of Hg2+ and Cu2+ and its applications in bacteria, cell imaging and food analysis.

BACKGROUND: Heavy metal pollution has become one of the world's most important environmental pollution, especially Hg2+ is enriched, it is easy to enter the human body through the food chain, bind to the sulfhydryl group in the protein, cause mercury poisoning. Traditional methods for detecting Hg2+ have obvious drawbacks, such as poor selectivity and long detection time. Fluorescence detection has attracted attention because of its good sensitivity and specificity detection ability. In previously reported probes for detecting Hg2+, Cu2+ often interferes. Therefore, it is of great practical significance to synthesize a fluorescent probe that can distinguish between Hg2+ and Cu2+. RESULTS: We have successfully synthesized the probe DFS, a fluorescent probe that can differentially detect Hg2+ and Cu2+, and the probe DFS has good selectivity and anti-interference ability for Hg2+ and Cu2+. The fluorescence intensity at 530 nm increased rapidly when Hg2+ was detected; during the Cu2+ detection, the fluorescence intensity at 636 nm gradually decreased, fluorescence quenching occurred, and the detection limits of Hg2+ and Cu2+ were 7.29 × 10-9 M and 2.13 × 10-9 M, respectively. Through biological experiments, it was found that probe DFS can complete the fluorescence imaging of Hg2+ and Cu2+ in Staphylococcus aureus and HUVEC cells, which has certain research value in the field of environmental monitoring and microbiology, and the probe DFS has low cytotoxicity, so it also has broad application prospects in the field of biological imaging. In addition, the probe DFS also has good applicability for Hg2+ and Cu2+ detection in actual samples. SIGNIFICANCE AND NOVELTY: This is a fluorescent probe that can distinguish between Hg2+ and Cu2+, the fluorescence emission peak appears at 530 nm when Hg2+ is detected; when detecting Cu2+, fluorescence quenching occurs at 636 nm, the fluorescence emission peak distance between Hg2+ and Cu2+ differs by 106 nm. This reduces mutual interference between Hg2+ and Cu2+ during detection, it provides a new idea for the detection of Hg2+ and Cu2+.

A novel "on-off-on" near-infrared fluorescent probe for Cu2+ and S2- continuous detection based on dicyanoisoflurone derivatives, and its application in bacterial imaging.

We have successfully synthesized a near-infrared fluorescent probe for the continuous detection of copper and sulfur ions. The probe has good selectivity and anti-interference ability against Cu2+ and S2-. The results show that after adding Cu2+ to the DL solution of the near-infrared fluorescent probe, Cu2+ forms a [DL + Cu2+] complex with the probe, which leads to fluorescence quenching due to the paramagnetism of Cu2+. The probe can be used for the quantitative detection of Cu2+ with a detection limit of 1.26 × 10-9 M. According to the Job's plot curve the binding stoichiometry between DL and Cu2+ is 1 : 1. Subsequently, S2- was added to the [DL + Cu2+] solution, because the precipitation dissolution equilibrium constant of CuS was Ksp = 1.27 × 10-36, so the binding capacity between Cu2+ and S2- was stronger, CuS precipitation was formed, and red fluorescence was re-released, and the quantitative detection of S2- was realized, and the detection limit was 3.50 × 10-8 M. Through bacterial imaging experiments, we found that the probe can accomplish the fluorescence imaging experiments of Staphylococcus aureus, indicating that the probe has good biopenetration and biocompatibility, and has application prospects in bioimaging and environmental monitoring. In addition, the probe DL has good suitability for Cu2+ and S2- detection in real samples.

Shear Stress and ROS Dual-Responsive RBC-Hitchhiking Nanoparticles for Atherosclerosis Therapy.

Atherosclerosis (AS), a leading cause of death worldwide, is a chronic inflammatory disease rich in lipids and reactive oxygen species (ROS) within plaques. Therefore, lowering lipid and ROS levels is effective in treating AS and reducing AS-induced mortality. In this study, an intelligent biomimetic drug delivery system that specifically responded to both shear stress and ROS microenvironment was developed, consisting of red blood cells (RBCs) and cross-linked polyethyleneimine nanoparticles (SA PEI) loaded with a lipid-lowering drug simvastatin acid (SA), and RBCs were self-assembled with SA PEI to obtain biresponsive SA PEI@RBCs for the treatment of AS. SA PEI could achieve sustained release of SA in response to ROS and reduce ROS and lipid levels to achieve the purpose of treating AS. Shear stress model experiments showed that SA PEI@RBCs could respond to the high shear stress level (100 dynes/cm2) at plaques, realizing the desorption and enrichment of SA PEI and improving the therapeutic efficiency of SA PEI@RBCs. In vitro and in vivo experiments have confirmed that SA PEI@RBCs exhibits better in vivo safety and therapeutic efficacy than SA PEI and free SA. Therefore, shaping SA PEI@RBCs into a biomimetic drug delivery system with dual sensitivity to ROS and shear stress is an effective strategy and treatment to facilitate their delivery into plaques.

Stromal cells in the tumor microenvironment: accomplices of tumor progression?

The tumor microenvironment (TME) is made up of cells and extracellular matrix (non-cellular component), and cellular components include cancer cells and non-malignant cells such as immune cells and stromal cells. These three types of cells establish complex signals in the body and further influence tumor genesis, development, metastasis and participate in resistance to anti-tumor therapy. It has attracted scholars to study immune cells in TME due to the significant efficacy of immune checkpoint inhibitors (ICI) and chimeric antigen receptor T (CAR-T) in solid tumors and hematologic tumors. After more than 10 years of efforts, the role of immune cells in TME and the strategy of treating tumors based on immune cells have developed rapidly. Moreover, ICI have been recommended by guidelines as first- or second-line treatment strategies in a variety of tumors. At the same time, stromal cells is another major class of cellular components in TME, which also play a very important role in tumor metabolism, growth, metastasis, immune evasion and treatment resistance. Stromal cells can be recruited from neighboring non-cancerous host stromal cells and can also be formed by transdifferentiation from stromal cells to stromal cells or from tumor cells to stromal cells. Moreover, they participate in tumor genesis, development and drug resistance by secreting various factors and exosomes, participating in tumor angiogenesis and tumor metabolism, regulating the immune response in TME and extracellular matrix. However, with the deepening understanding of stromal cells, people found that stromal cells not only have the effect of promoting tumor but also can inhibit tumor in some cases. In this review, we will introduce the origin of stromal cells in TME as well as the role and specific mechanism of stromal cells in tumorigenesis and tumor development and strategies for treatment of tumors based on stromal cells. We will focus on tumor-associated fibroblasts (CAFs), mesenchymal stem cells (MSCs), tumor-associated adipocytes (CAAs), tumor endothelial cells (TECs) and pericytes (PCs) in stromal cells.

Hyaluronic acid targeted and pH-responsive multifunctional nanoparticles for chemo-photothermal synergistic therapy of atherosclerosis.

Atherosclerosis is a global disease with an extremely high morbidity and fatality rate, so it is necessary to develop effective treatments to reduce its impact. In this work, we successfully prepared a multifunctional drug-loaded nano-delivery system with pH-responsive, CD44-targeted, and chemical-photothermal synergistic treatment. Dendritic mesoporous silica nanoparticles capped with copper sulfide (CuS) were synthesized via an oil-water biphase stratification reaction system; these served as the carrier material and encapsulated the anticoagulant drug heparin (Hep). The pH-sensitive Schiff base bond was used as a gatekeeper and targeting agent to modify hyaluronic acid (HA) on the surface of the nanocarrier. HA coating endowed the nanocomposite with the ability to respond to pH and target CD44-positive inflammatory macrophages. Based on this multifunctional nanocomposite, we achieved precise drug delivery, controlled drug release, and chemical-photothermal synergistic treatment of atherosclerosis. The in vitro drug release results showed that the nanocarriers exhibited excellent drug-controlled release properties, and could release drugs in the weakly acidic microenvironment of atherosclerotic inflammation. Cytotoxicity and cell uptake experiments indicated that nanocarriers had low cytotoxicity against RAW 264.7 cells. Modification of HA to nanocarriers can be effectively internalized by RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Combining CuS photothermal treatment with anti-atherosclerosis chemotherapy showed better effects than single treatment in vitro and in vivo. In summary, our research proved that H-CuS@DMSN-NC-HA has broad application prospects in anti-atherosclerosis.

Advances in electrospun nanofibrous membrane sensors for ion detection.

Harmful metal ions and toxic anions produced in industrial processes cause serious damage to the environment and human health. Chemical sensors are used as an efficient and convenient detection method for harmful ions. Electrospun fiber membranes are widely used in the field of solid-state chemical sensors due to high specific surface area, high porosity, and strong adsorption. This paper reviews the solid-state chemical sensors based on electrospinning technology for the detection of harmful heavy metal ions and toxic anions in water over the past decade. These electrospun fiber sensors have different preparation methods, sensing mechanisms, and sensing properties. The preparation method can be completed by physical doping, chemical modification, copolymerization, surface adsorption and self-assembly combined with electrospinning, and the material can also be combined with organic fluorescent molecules, biological matrix materials and precious metal materials. Sensing performance aspects can also be manifested as changes in color and fluorescence. By comparing the literature, we summarize the advantages and disadvantages of electrospinning technology in the field of ion sensing, and discuss the opportunities and challenges of electrospun fiber sensor research. We hope that this review can provide inspiration for the development of electrospun fiber sensors.

A novel Near-Infrared fluorescent probe for Zn2+ and CN- double detection based on dicyanoisfluorone derivatives with highly sensitive and selective, and its application in Bioimaging.

We have successfully synthesized NIRF as a near-infrared fluorescence probe for relay recognition of zinc and cyanide ions. The probe possesses well selectivity and anti-interference ability over common ions towards Zn2+ and CN-. The results showed that Zn2+ and the probe formed [NIRF-Zn2+] complex after added Zn2+ into the probe NIRF solution, which emited red fluorescence. The probe can be used for quantitative detection of Zn2+ with a detection limit of 4.61 × 10-8 M. It was determined that the binding stoichiometry between the NIRF and Zn2+ was 1:1 according to the job,s curve. Subsequently, CN- was added to the NIRF-Zn2+ solution, CN- combined with Zn2+ to generate [Zn(CN-)x]1-x due to the stronger binding ability between zinc ion and cyanogen, which lead to the red fluorescence disappeared. The quantitative detection of CN- was realized with a detection limit of 7.9 × 10*7 M. In addition, the probe has excellent specificity and selectivity for Zn2+ and CN-. And the probe can be stable in a wide range of pH. Through biological experiments, we found that it can complete cell imaging in macrophages and imaging of living mice, which has application prospects in Bioimaging. In addition, the probe NIRF has good applicability for Zn2+ and CN- detection in actual samples.

Layer-by-layer assembled Fe3O4@C@CdTe core/shell microspheres as separable luminescent probe for sensitive sensing of Cu2+ ions.

A novel multifunctional microsphere with a fluorescent CdTe quantum dots (QDs) shell and a magnetic core (Fe(3)O(4)) has been successfully developed and prepared by a combination of the hydrothermal method and layer-by-layer (LBL) self-assembly technique. The resulting fluorescent Fe(3)O(4)@C@CdTe core/shell microspheres are utilized as a chemosensor for ultrasensitive Cu(2+) ion detection. The fluorescence of the obtained chemosensor could be quenched effectively by Cu(2+) ions. The quenching mechanism was studied and the results showed the existence of both static and dynamic quenching processes. However, static quenching is the more prominent of the two. The modified Stern-Volmer equation showed a good linear response (R(2) = 0.9957) in the range 1-10 µM with a quenching constant (K(sv)) of 4.9 × 10(4) M(-1). Most importantly, magnetic measurements showed that the Fe(3)O(4)@C@CdTe core/shell microspheres were superparamagnetic and they could be separated and collected easily using a commercial magnet in 10 s. These results obtained not only provide a way to solve the embarrassments in practical sensing applications of QDs, but also enable the fabrication of other multifunctional nanostructure-based hybrid nanomaterials.

Rhodamine-based highly sensitive colorimetric off-on fluorescent chemosensor for Hg2+ in aqueous solution and for live cell imaging.

A novel rhodamine-based highly sensitive and selective colorimetric off-on fluorescent chemosensor for Hg(2+) ions is designed and prepared by using the well-known thiospirolactam rhodamine chromophore and furfural hydrazone as signal-reporting groups. The photophysical characterization and Hg(2+)-binding properties of sensor RS1 in neutral N, N-dimethylformamide (DMF) aqueous solution are also investigated. The signal change of the chemosensor is based on a specific metal ion induced reversible ring-opening mechanism of the rhodamine spirolactam. The response of the chemosensor for Hg(2+) ions is instantaneous and reversible. And it successfully exhibits a remarkably "turn on" response toward Hg(2+) over other metal ions (even those that exist in high concentration). Moreover, this sensor is applied for in vivo imaging in Rat Schwann cells to confirm that RS1 can be used as a fluorescent probe for monitoring Hg(2+) in living cells with satisfying results, which further demonstrates its value of practical applications in environmental and biological systems.

Shear stress and ROS-responsive biomimetic micelles for atherosclerosis via ROS consumption.

Reactive oxygen species (ROS) are well-known important initiating factors required for atherosclerosis formation, which leads to endothelial dysfunction and plaque formation. Most of the existing antithrombotic therapies use ROS-responsive drug delivery systems, which have a certain therapeutic effect but cannot eliminate excess ROS. Therefore, the atherosclerosis cannot be treated from the source. Moreover, nanoparticles are easily cleared by the immune system during blood circulation, which is not conducive to long-term circulation. In this study, we developed an intelligent response system that could simultaneously respond to ROS and the shear stress microenvironment of atherosclerotic plaques. This system was formed by red blood cells (RBCs) and simvastatin-loaded micelles (SV MC). The micelles consisted of poly(glycidyl methacrylate)-polypropylene sulfide (PGED-PPS). The hydrophobic PPS could react with excess ROS to become hydrophilic, which forced the micelle rupture, resulting in drug release. Most importantly, PPS could also significantly deplete the ROS level, realizing the synergistic treatment of atherosclerosis with drugs and materials. The positively charged SV MC and negatively charged RBCs were self-assembled through electrostatic adsorption to obtain SV MC@RBCs. The SV MC@RBCs could respond to the high shear stress at the atherosclerotic plaque, and the shear stress induced SV MC desorption from the RBC surface. Using biomimetic methods to evade the SV MC@RBCs elimination by the immune system and to reduce the ROS plays a vital role in improving atherosclerosis treatment. The results of in vitro and in vivo experiments showed that SV MC@RBCs could effectively treat atherosclerosis. Moreover, not only does the SV MC@RBCs system avoid the risk of bleeding, but it also has excellent in vivo safety. The study results indicate that the SV MC@RBCs system is a promising therapeutic nanomedicine for treating ROS-related diseases.

A ROS and shear stress dual-sensitive bionic system with cross-linked dendrimers for atherosclerosis therapy.

Atherosclerosis is an important pathological basis for cardiovascular disease. Thus, the treatment of atherosclerosis can effectively improve the prognosis and reduce the mortality of cardiovascular diseases. In this study, we developed simvastatin acid (SA)-loaded cross-linked dendrimer nanoparticles (SA PAM) that were adsorbed to the surface of red blood cells (RBCs) to obtain SA PAM@RBCs, a ROS and shear stress dual response drug delivery system for the treatment of atherosclerosis. SA PAM could continuously release SA in an H2O2-triggered manner, and effectively eliminate excessive H2O2 in LPS-stimulated RAW 264.7 cells, achieving the target of using the special microenvironment at the plaque to release drugs. At the same time, the shear sensitive model also proved that only 12.4% of SA PAM detached from the RBCs under low shear stress (20 dynes per cm2), while 61.3% SA PAM desorbed from the RBCs under a high shear stress (100 dynes per cm2) stimulus, revealing that SA PAM could desorb in response to the shear stress stimulus. Both the FeCl3 model and ApoE-/- model showed that SA PAM@RBCs had better therapeutic effects than free SA, and with excellent safety in vivo. Therefore, a biomimetic drug delivery system with dual sensitivity to ROS and shear stress would become a promising strategy for the treatment of atherosclerosis.

A novel mitochondrial-targeting fluorescent probe based on 1,4-dihydropyridine to visualize and monitor the viscosity of live cells and mice in vivo.

Cell viscosity is related to some diseases, such as diabetes, atherosclerosis, and Alzheimer's disease. These diseases can cause abnormal viscosity of the cell mitochondrial matrix. 1,4-Dihydropyridine (DHP) is an important organic compound with biological activity and is widely used in drug research. However, there are few studies on its optical properties, especially in the design of viscous fluorescent probes. In this study, a fluorescent probe for viscosity detection using 1,4-dihydropyridine as the fluorophore and indole iodide salt as the recognition group was designed and synthesized. The probe has the advantages of a deep-red emission, low cytotoxicity, good biocompatibility and excellent anti-interference ability. In addition, the probe also has the ability to target mitochondria and has been successfully applied to the detection of the viscosity response of HeLa cells and living mice, and has good clinical application potential.

A novel fluorescent probe based on a triphenylamine derivative for the detection of HSO3- with high sensitivity and selectivity.

A novel highly active fluorescence chemical sensor (TBQN) for HSO3- was synthesized by the Knoevenagel reaction based on triphenylamine-benzothiazole as a new fluorophore. The probe possessed good selectivity toward HSO3- and anti-interference ability with common ions. The fluorescence and UV-vis spectra of the TBQN probe were significantly changed after the addition of HSO3-. At the same time, the probe solution released obvious green fluorescence. Moreover, the limit of detection for HSO3- was calculated to be 3.19 × 10-8 M. The TBQN probe displayed a rapid response to HSO3- and it took about 3 min to complete the recognition. The detection mechanism is the nucleophilic addition reaction between HSO3- and -C[double bond, length as m-dash]C- in the probe molecule. The π-conjugation and ICT (intramolecular charge transfer) transition in the TBQN molecule were destroyed by this addition, which resulted in the change of the fluorescence before and after the addition of HSO3-. Then, the mechanism was verified by theoretical calculations, 1H NMR measurements and mass spectroscopy. In addition, the probe showed low cytotoxicity and could be used for biological imaging in RAW264.7 cells.