A polystyrene-based ESIPT fluorescent polymeric probe for highly sensitive detection of chromium(vi) ions and protein staining.

A "two-step" preparation method of an excited-state intermolecular proton transfer (ESIPT) fluorescent polymer (f-PP) is reported here. The synthesis of f-PP involves the acetylation of polystyrene and a "multicomponent one pot" reaction. The as-prepared polymer bears a group of ESIPT fluorescent units, enabling it to exhibit high brightness, moderate solubility and ESIPT fluorescence.

A fluorescent probe based on modulation of ESIPT signaling for the highly selective detection of NH and cell-imaging.

The broad occurrence of the hydrazine (NH) residues in aqueousenvironment is a potential threat to human health. Currently, the mainstream strategy for designing NH-specific probes is to functionalize a fluorophore with nucleophilic sites for the reductionreaction with NH. In this work, we designed and synthesized an excited-state intermolecular proton transfer (inter-ESPT) fluorescent dye(2-amino-4-(4-methoxyphenyl)-7,8-dihydro-5H-spiro[quinoline-6,2'-[1,3]dioxolane]-3-carbonitrilem, DQN) and used it as a probe to sense NH.

Spectral Properties Echoing the Tautomerism of Milrinone and Its Application to Fe Ion Sensing and Protein Staining.

Knowledge on the spectral properties of the tautomers of milrinone (MLR) in solvents and solid-state, as well as under light conditions is of critical importance from both theoretical and practical points of view. Herein, we investigated the spectral properties of MLR in different conditions using UV-Vis and fluorescence spectroscopies. The experimental results demonstrated that MLR can undergo the tautomerization reaction induced by solvent polarity, light and pH, eliciting four tautomeric structures (enol, keto, anion, and cation forms).

Partnered Excited-State Intermolecular Proton Transfer Fluorescence (P-ESIPT) Signaling for Nitrate Sensing and High-Resolution Cell-Imaging.

Nitrite (NO) is a common pollutant and is widely present in the environment and in human bodies. The development of a rapid and accurate method for NO detection is always a very important task. Herein, we synthesized a partnered excited-state intermolecular proton transfer (ESIPT) fluorophore using the "multi-component one pot" method, and used this as a probe (ESIPT-F) for sensing NO.

A Solvent-Mediated Excited-State Intermolecular Proton Transfer Fluorescent Probe for Fe Sensing and Cell Imaging.

Constructing excited-state intermolecular proton transfer (ESIPT-e) fluorophores represents significant challenges due to the harsh requirement of bearing a proton donor-acceptor (D-A) system and their matching proton donating-accepting ability in the same molecule. Herein, we synthesized a new-type ESIPT-e fluorophor (2-APC) using the "four-component one-pot" reaction. By the installing of a cyano-group on pyridine scaffold, the proton donating ability of -NH was greatly enhanced, enabling 2-APC to undergo ESIPT-e process.

A solvent-assisted ESIPT fluorescent dye for F/Ag sensing and high-resolution imaging of the cilia in live cells.

A solvent-assisted ESIPT fluorescent dye was synthesized and used as a probe (2-PPN) for the detection of F/Ag and high-resolution imaging of the cilia in live cells. The developed ESIPT fluorophore exhibited strong tautomeric fluorescence in protic solvents and normal emission in aprotic solvents, which is a significant departure from that of conventional intramolecular ESIPT compounds. The H-binding interaction of F and the chelation of Ag with the ESIPT module of 2-PPN resulted in significant tautomeric emission quenching.

Detection of Single Nucleotide Polymorphisms by Fluorescence Embedded Dye SYBR Green I Based on Graphene Oxide.

The detection of single nucleotide polymorphisms (SNPs) is of great significance in the early diagnosis of diseases and the rational use of drugs. Thus, a novel biosensor based on the quenching effect of fluorescence-embedded SYBR Green I (SG) dye and graphene oxide (GO) was introduced in this study. The probe DNA forms a double helix structure with perfectly complementary DNA (pcDNA) and 15 single-base mismatch DNA (smDNA) respectively.

Intrinsically ESIPT-exhibiting and enhanced emission in polymer nanoparticles as signaling for sensing nitrite.

A straightforward approach to the fabrication of intrinsically excited-state intramolecular proton transfer (ESIPT)-fluorescent polymer nanoparticles (e-PNPs) was developed. The e-PNPs were obtained by self-assembly of the homopolymers derived from 4-aminosalicylic acid in aqueous solution. By incorporating ESIPT modules into polymer nanoparticles, the ESIPT reaction can be endowed with moderate hydrophobic micro-environment by nanoparticle scaffolds, eliciting enhanced ESIPT emission.

Intrinsically fluorescent and highly functionalized polymer nanoparticles as probes for the detection of zinc and pyrophosphate ions in rabbit serum samples.

Intrinsically fluorescent polymer nanoparticles (F-PNPs) were synthetized from 2-hydroxy-5-methylisophthalaldehyde and melamine by solvothermal method. F-PNPs can emit strong yellow green fluorescence at 542 nm without the conjugation to any external fluorescent agent and surface modification. Owing to the abundant amino and hydroxyl groups on their surface, the F-PNPs possess multiple binding sites, good biocompatibility and excellent water-solubility.

Targeted Imaging of Brain Tumors with a Framework Nucleic Acid Probe.

Development of agents for delivering drugs and imaging probes across the blood-brain barrier (BBB) remains a major challenge. In this study, we designed a biocompatible framework nucleic acid (FNA)-based imaging probe for brain tumor-targeting. We employed a typical type of FNAs, tetrahedral DNA nanostructures (TDNs), as the building block, which were modified with angiopep-2 (ANG), a 19-mer peptide derived from human Kunitz domain of aprotinin.

A specific nanoprobe for cysteine based on nitrogen-rich fluorescent quantum dots combined with Cu.

As a new member of the carbon quantum-dot family, fluorescent nitrogen-rich quantum dots (NRQDs) were prepared by a mixed solvothermal method using 2-azidoimidazole and aqueous ammonia as reactants. These NRQDs are rich in nitrogen up to 40.2%, which are endowed with high fluorescence quantum yield, good photostability, water-solubility and favourable biocompatibility.

Electrochemical detection of PCR amplicons of Escherichia coli genome based on DNA nanostructural probes and polyHRP enzyme.

Fast, portable and sensitive analysis of E. coli is becoming an important challenge in many critical fields (e.g.

Multiple-Armed Tetrahedral DNA Nanostructures for Tumor-Targeting, Dual-Modality in Vivo Imaging.

In this work, we have developed multiple-armed DNA tetrahedral nanostructures (TDNs) for dual-modality in vivo imaging using near-infrared (NIR) fluorescence and single-photon emission computed tomography (SPECT). We found that the presence of arm strands in TDNs remarkably enhanced their in vitro stability, allowing them to stay intact for at least 12 h in serum. By using NIR fluorescence imaging, we evaluated in mice the pharmacokinetics of TDNs, which exhibited distinctly different in vivo biodistribution patterns compared with those of double-stranded (ds)DNA.

Synthesis and receptor binding assay of indolin-2-one derivatives as dopamine D4 receptor ligands.

Five indolin-2-one derivatives bearing piperazinylbutyl side chains attached to the amide nitrogen were synthesized from 2-indolinone. 1-(4-Bromobutyl)-indolin-2-one was reacted with 1-piperazinecarboxaldehyde to form 1-(4-(4-formyl-1-piperazinyl)butyl)indolin-2-one (2). In the presence of H2SO4, the aldehyde moiety was removed from 1-(4-(4-formyl-1-piperazinyl)butyl)indolin-2-one and then 1-(4-(1-piperazinyl)butyl)indolin-2-one (3) was obtained, this compound was reacted with benzaldehyde derivatives to give the target compounds 4 a-e by N-alkylation reaction.

Universal Fluorescence Biosensor Platform Based on Graphene Quantum Dots and Pyrene-Functionalized Molecular Beacons for Detection of MicroRNAs.

A novel biosensor platform was developed for detection of microRNAs (miRNAs) based on graphene quantum dots (GQDs) and pyrene-functionalized molecular beacon probes (py-MBs). Pyrene was introduced to trigger specifically fluorescence resonance energy transfer (FRET) between GQDs and fluorescent dyes labeled on py-MBs, and the unique fluorescent intensity change produced a novel signal for detection of the target. The platform realized detection of miRNAs in a wide range from 0.

Constructing Higher-Order DNA Nanoarchitectures with Highly Purified DNA Nanocages.

DNA nanostructures have attracted great attention due to their precisely controllable geometry and great potential in various areas including bottom-up self-assembly. However, construction of higher-order DNA nanoarchitectures with individual DNA nanostructures is often hampered with the purity and quantity of these "bricks". Here, we introduced size exclusion chromatography (SEC) to prepare highly purified tetrahedral DNA nanocages in large scale and demonstrated that precise quantification of DNA nanocages was the key to the formation of higher-order DNA nanoarchitectures.

Metal ion-mediated assembly of DNA nanostructures for cascade fluorescence resonance energy transfer-based fingerprint analysis.

Contamination of heavy metal ions in an aquatic environment poses a serious threat to human health. More seriously, heavy metal ions are usually present in the environment in a mixture, and the synergetic toxicity of multiple heavy metal ions is revealed (Aragay et al. Chem.

A novel fluorescence sensor based on covalent immobilization of 3-amino-9-ethylcarbazole by using silver nanoparticles as bridges and carriers.

A novel technique of covalent immobilization of indicator dyes in the preparation of fluorescence sensors is developed. Silver nanoparticles are used as bridges and carriers for anchoring indicator dyes. 3-amino-9-ethylcarbazole (AEC) was employed as an example of indicator dyes with terminal amino groups and covalently immobilized onto the outmost surface of a quartz glass slide.

Surface modified superparamagnetic iron oxide nanoparticles: as a new carrier for bio-magnetically targeted therapy.

Amino-functionalized superparamagnetic iron oxide nanoparticles (SPION) were synthesized by coprecipitation method. The particles were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron micrographs (SEM), transmission electron micrographs (TEM) and atomic force micrographs (AFM). The size of the modified particles varied in the range 10-15 nm and did not change significantly after modification.

Radiolabelling of poly(histidine) derivatized biodegradable microspheres with the 188Re tricarbonyl complex [188Re(CO)3(H2O)3]+.

Objectives: Many radiopharmaceuticals have been studied as radiation synovectomy agents. In this study, we developed a new potential agent for radiation synovectomy: poly(lactic acid)-histidine (PLA-his) microspheres radiolabelled with [188Re(CO)3(H2O)3]+.

Methods: The reaction conditions for the chelation of [188Re(CO)3(H2O)3]+ and the radiolabelling of PLA microspheres were optimized and the stabilities for both steps tested in vitro.