Biomarker-targeted fluorescent probes for breast cancer imaging

This review summarized fluorescent probes for breast cancer imaging according to different biomarkers probes recognized.     

Site-specific DNA-programmed growth of fluorescent and functional silver nanoclusters

Precise organization of metallic nanoclusters on DNA scaffolds holds great interest for nanopatterned materials that may find uses in electronics, sensors, medicine, and many other fields. Herein, we report the site-specific growth of fluorescent silver nanoclusters by using a mismatched double-stranded DNA template. Few-atom, molecular-scale Ag clusters are found to localize at the mismatched site and the metallized DNA retains its integrity. The DNA-encapsulated nanoclusters can be utilized as functional biological probes to identify single-nucleotide polymorphisms by taking advantage of the very bright fluorescence and excellent photostability of the nanoclusters. This approach offers the possibility of constructing novel DNA-based nanomaterials and nanomechanical devices with more sophisticated functions and will be highly beneficial in future biochemical, pharmaceutical, nanomechanical, and electronic applications.     

Synthesis and characterization of new selective Zn fluorescent probes for functionalization: in vitro Cell imaging applications

Herein the synthesis and characterization of new, lipophilic highly Zn²⁺-selective fluorescent probes are reported. High affinity for zinc (K_d 1.1–8.0 nM) over other biologically relevant metals and mixtures of metals was observed. Excitation at 360 nm afforded an emission spectrum with maximum at 530 nm for the zinc bound complex. The linear relationship between fluorescence intensity and zinc concentration indicates that FZnA-probes can be used for quantification. The probes have been synthesized in 28–45% overall yield and the feasibility for further functionalization with biologically relevant side chains has been demonstrated. In vitro studies using PC12 cells and 10 μM of one of the novel probes (FZnA-Ada) visualized endogenous labile Zn²⁺ after 45 min incubation time.     

Bifunctionalised long-wavelength fluorescent probes for biological applications

The synthesis of benzo[a]phenoxazinium chlorides which are bifunctionalised in position 2 with 4-ethoxy-4-oxobutoxyl, 3-hydroxypropoxyl or 3-chloropropoxyl groups, and in position 9 with the (aminopropyl)amino group, was efficiently performed. The covalent labelling of valine was carried out by using one of the new fluorophores obtained. Photophysical studies in the homogeneous media of ethanol, distilled water and simulated physiological conditions revealed that all the compounds absorbed and emitted from 610 to 651 nm.     

Molecularly near-infrared fluorescent theranostics for in vivo tracking tumor-specific chemotherapy

Molecularly near-infrared(NIR) theranostics, combining in vivo sensing and tumor-specific therapeutic capability within one molecular system, have received considerable attention in recent years. Compared with the visible fluorescence imaging, NIR imaging(emission wavelength at 650–900 nm) possesses unique advantages including the minimum photodamage to biological samples, deep penetration, and low interference from auto-fluorescence. In over past decades, there has been an explosive development in the design of molecular imaging contrasts and imaging-guided therapeutics. In this review, we have sumarried the strategies of the NIR theranostics for imaging and tumor-specific chemotherapy applications in living systems. It is noted that the molecularly NIR theranostic design strategy could address current challenges of real-time in vivo sense-and-release for the intelligent biosensing and personalized treatment.     

Molecularly near-infrared fluorescent theranostics for in vivo tracking tumor-specific chemotherapy

In this review, we summary the design concepts and strategies of NIR fluorescent theranostics for the senserelease in living systems. In particular, molecularly NIR fluorescent theranostic prodrug is elucidated to address current challenges of real-time bioimaging and tumor-specific chemotherapy for personalized treatment.     

Facile synthesis of near infrared fluorescent trypsin-stabilized Ag nanoclusters with tunable emission for 1,4-dihydronicotinamide adenine dinucleotide and ethanol sensing

A facile chemical synthetic route was developed to prepare near-infrared fluorescent trypsin-stabilized Ag nanoclusters (Try-Ag NCs). The fluorescence emission wavelength of the produced Try-Ag NCs is tunable by simple adjusting pH value of the synthesis system, and the Try-Ag NCs offer a symmetric fluorescent excitation and emission peak. The fluorescence of Try-Ag NCs remains constant in the presence of various ions and molecules, and it can be effectively quenched by 1,4-dihydronicotinamide adenine dinucleotide (NADH) instead of its oxidized forms nicotinamide adenine dinucleotide (NAD⁺). This property enables the Try-Ag NCs to be a novel analytical platform to monitor biological reaction involved with NADH. In this work, the Try-Ag NCs was also applied to analyze ethanol based on the generation of NADH which was the product of NAD⁺ and ethanol in the catalysis of alcohol dehydrogenase. And the proposed platform allowed ethanol to be determined in the range from 10 to 300 μmol/L with 5 μmol/L detection limit.     

A ratiometric near-infrared naphthalimide-based fluorescent probe with high sensitivity for detecting Fe2+ in vivo

Iron is one of the essential trace elements in the human body. It plays an important role in human biology and pathology. Deregulation of iron levels in cells is associated with disease development. In this work, we synthesized a novel near-infrared intramolecular charge transfer (ICT) based ratiometric fluorescent probe to detect Fe²⁺, by using naphthalimide and indole moieties as building blocks. Our work showed that the radiometric probe has excellent selectivity, sensitivity and rapid response. Moreover, we could successfully perform real-time monitoring of Fe²⁺ in HeLa cells and C. elegans.     

金属纳米簇在CO2光催化还原中的研究进展

化石燃料的大量燃烧不仅造成能源危机,而且排放的二氧化碳（CO2）会使气候变暖。以清洁、储量丰富的太阳光作为能量来源,将CO2光催化还原为高附加值的化学产品是缓解当前环境问题和能源问题的主要方法之一。然而,CO2在常温常压下非常的稳定,因此需要设计并构筑高效光催化剂来捕捉和转化CO2,以达到高效光催化CO2还原的目的。在众多研究的光催化剂中,金属纳米簇因其具有独特的结构特点、优异的物理和化学性质,所以在光催化CO2还原领域得到了广泛的应用。基于此,我们首先对金属纳米簇进行了分类,将其分为贵金属纳米簇和非贵金属纳米簇;然后分别对贵金属和非贵金属纳米簇在光催化CO2还原中的研究进展进行了归纳与总结。本文通过及时全面概述近几年该领域的研究进展,从而为未来研究方向提供新思路。     

Biomolecules as promising ligands in the synthesis of metal nanoclusters: Sensing,bioimaging and catalytic applications

The use of metal nanoclusters as sensing probes has recently attracted considerable interest from researchers. In particular, metallic nanoclusters (e.g., Au, Ag, Cu, Pt) have been noticed a wide range of applications in the field of fluorescence sensing and bioimaging. The stabilization of metal nanoclusters with organic molecules, proteins, and amino acids enhances their optical properties and analytical applications. In this review, synthetic routes for the fabrication of metal nanoclusters are summarized. This review also describes the metal nanoclusters properties including aggregation-induced emission, optical absorption, non-linear optical, and chiral properties. We discussed the analytical applications of metal nanoclusters for sensing of wide variety of analytes including drugs, biomolecules, biomarkers. Further, the catalytic applications of metal nanoclusters are also briefly summarized. Finally, we summarize the challenges and future perspectives of metal nanoclusters in analytical chemistry.     

Fine-tailoring the linker of near-infrared fluorescence probes for nitroreductase imaging in hypoxic tumor cells

Fine-tailoring the linker of nitroreductase fl uorescence probes with a given recognition unit and reporting unit is found to be able to achieve the best sensing performance.     

A pinacol boronate caged NIAD-4 derivative as a near-infrared fluorescent probe for fast and selective detection of hypochlorous acid

A pinacol boronate caged NIAD-4 derivative was demonstrated to be a near-infrared fluorescent probe for fast and selective detection of hypochlorite over other ROS species.     

A near-infrared fluorescent probe for monitoring fluvastatin-stimulated endogenous H2S production

Most reported fluorescent probes have limitations in practical applications in living systems due to the strong autofluorescence background,construction of probes with near-infrared(NIR) fluorescence emission is an accessible approach for addressing this challenge.We here designed a NIR fluorescent probe for monitoring the endogenous production of H_2S in living cells.The designed probe showed significant NIR fluorescence turn-on response to H_2S with high selectivity,enabling the sensitive detection H_2S.Importantly,the probe could be applied in monitoring the endogenous production of H_2S in raw 264.7 macrophages.This study showed that fluvastatin can promote the activity of cystathionineγ-lyase(CSE) for generation H_2S.     

Template Controlled Synthesis (TCS) of size-controlled metal nanoclusters: preparation of nanostructured metals supported by inorganic supports

Strictly size-controlled metal nanoclusters of palladium(0) and gold(0) can be easily formed in the organic component of an organic-inorganic composite between a gel-type resin (DV44) and silica. To this purpose, silica is impregnated at incipient wetness with a solution of the required co-monomers (N,N-dimethylacrylamide, 4-vinylpyridine and N,N′-methylene-bis-acrylamide), which are co-polymerized to give the composite. The silica-supported polymeric framework is then loaded with palladium(II) or gold(III) precursors. Their chemical reduction with aqueous solutions of sodium boronhydride yields the metal nanoclusters. Their size is controlled by the nanomorphology of the polymeric framework, which acts as a template during the nanocluster growth (Template Controlled Synthesis). Upon thermal decomposition of the polymeric template at 600°C under nitrogen, the nanostructured metals are deposited onto the silica surface. In the case of palladium the final step occurs with retention of the original size of the nanoclusters.     

Two near-infrared highly sensitive cyanine fluorescent probes for pH monitoring

Two near-infrared(NIR) p H-activated heptamethine indocyanine probes with quaternary ammonium unit were designed and synthesized. The absorption and emission titrations indicate that cationic structure improves the cyanine dye's aqueous solubility and these two probes exhibit highly sensitive response to p H in acid condition. Their fluorescence intensities both gradually increase about 25-fold from p H 7.60 to 3.00 with p Ka values of 4.72 and 4.45 respectively, which are suitable for studying acidic organelles in living cells. Moreover, their fluorescence intensities are linearly proportional to p H values in the range of 5.50–4.00. These results are probably attributed to the protonation of the indole nitrogen atoms, which are verified by 1H NMR spectra. Furthermore, these two probes can achieve real-time imaging of cellular p H and detection of p H in situ in living He La cells due to their excellent properties,including good reversibility, desirable photostability, high selectivity, low cytotoxicity and remarkable membrane permeability.     

Progress on the development of DNA-mediated metal nanomaterials for environmental and biological analysis

This review summarized the recent progress on the synthesis, morphologies and properties of DNA-mediated metal nanomaterials including nanoparticles and nanoclusters. Moreover, their applications to environmental and biological analysis were introduced with the developing prospect in analytical chemistry.     

A lysosomal targeting fluorescent probe and its zinc imaging in SH-SY5Y human neuroblastoma cells

A fluorescent probe based PET mechanism was designed, and the probe could image endogenous release of Zn²⁺ upon H₂O₂ stimulation in SH-SY5Y cells.     

DNA as a template for synthesis of fluorescent gold nanoclusters

Water-soluble blue-emitting gold nanoclusters have been synthesized using dsDNA as a template without any additional reducing agent. The features of the formed nanoclusters have been revealed by fluorescence and electronic absorption spectroscopy as well as transmission electron microscopy. The prepared gold nanoclusters have been highly stable at physiological pH without any further modification.     

Recent development on peptide-based probes for multifunctional biomedical imaging

Peptide-based probes play prominent roles in biomedical research due to their promising properties such as high biocompatibility, fast excretion, favorable pharmacokinetics as well as easy and robust preparation. Considering the translation of imaging probes into clinical applications, peptide-based probes remain to be the most desirable and optimal candidates.