Metal enhanced fluorescence

Photosensitizer (PS) with enhanced fluorescence is attractive for image-guided photodynamic therapy (PDT) due to its dual functional role in Singlet Oxygen Generation (SOG) and producing high fluorescence signals. Here, Eosin-Y (Ey) decorated polymer coated gold nanorods (GNRs) of different aspect ratios are synthesized and introduced as novel plasmon-enhanced nano-photosensitizers for this purpose. We show, upon excitation at 519 nm, simultaneous enhancement in fluorescence and SOG was achieved for the hybrid nanostructure...

Precise monitoring and quantification of H2 O2 is highly urgent and of great significance for biomedicine, food safety, environmental monitoring, etc . Herein, we proposed a facile near-infrared (NIR) excited fluorescent probe composed of upconversion nanoparticles (UCNPs) and non-metallic plasmonic WO3- x for ultrasensitive quantitative H2 O2 detection. Plasmonic WO3- x with oxygen vacancy-induced LSPR achieved over 680-fold enhancement of upconversion fluorescence at 520 nm, and also acts as the sensitive recognition site for H2 O2 ...

Ultrathin 2D metal-organic frameworks (MOFs) exhibit a myriad of unparalleled properties, rendering them extensively applicable across various fields. Despite this, developing a 2D MOF sensor for detecting hazardous amines in water remains a formidable challenge. To address this issue, we synthesized Ni- btc MOF ultrathin nanosheets with a thickness of approximately 4.15 nm for the detection of amines in water. These nanosheets demonstrated a notable "turn-on" fluorescence response in the presence of ammonia and aliphatic amines...

Quasi-2D perovskites have emerged as highly promising materials for application in perovskite light-emitting diodes (PeLEDs), garnering significant attention due to their outstanding semiconductor properties. These materials boast an inherent multi-quantum well structure that imparts a robust confinement effect, particularly advantageous for blue emission. However, the development of blue emitters utilizing quasi-2D perovskites encounters challenges, notably colour instability, multipeak emission, and suboptimal fluorescence yield...

2,6-Pyridinedicarboxylic acid (DPA) is a significant biomarker of anthrax, which is a deadly infectious disease for human beings. However, the development of a convenient anthrax detection method is still a challenge. Herein, we report a novel europium metal-organic framework (Eu-MOF) with an enhanced peroxidase-like activity and fluorescence property for DPA detection. The Eu-MOF was one-step synthesized using Eu3+ ions and 2-methylimidazole. In the presence of DPA, the intrinsic fluorescence of Eu3+ ions is sensitized, the fluorescence intensity linearly increases with an increase in DPA concentration, and the fluorescence color changes from blue to purple...

Understanding driving forces for dissipative, i.e., out of equilibrium, assembly of nanoparticles from colloidal solution at liquid-solid interfaces provides the ability to design external cues for reconfigurable device response. Here electrohydrodynamic flow (EHD) at an electrode-liquid interface is investigated as a dissipative driving force for tuning optical response. EHD results from an oscillatory electric field in a liquid cell between two electrodes and drives assembly of gold nanoparticles (NP) into two-dimensional clusters on electrode surfaces...

Bio-orthogonal chemistry provides a powerful tool for drug delivery systems due to its ability to generate therapeutic agents in situ, minimizing off-target effects. Bio-orthogonal transition metal catalysts (TMCs) with stimuli-responsive properties offer possibilities for controllable catalysis due to their spatial-, temporal-, and dosage-controllable properties. In this paper, we fabricated a stimuli-responsive bio-orthogonal catalysis system based on an enhanced green fluorescent protein (EGFP)-nanozyme (NZ) complex (EGFP-NZ)...

Water, although an important part of everyday life, is acts as one of the most significant contaminants in various applications such as biomedical monitoring, chemical production, petroleum-based fuel and food processing. In fact, the presence of water in other solvents is a huge concern. For the quantification of trace water content, different methods such as Karl-Fischer, electrochemical, nuclear magnetic resonance, chromatography, and thermogravimetric analysis have been used. Although every technique has its own benefit, each one suffers from several drawbacks that include high detection costs, lengthy procedures and specialized operations...

Detecting heavy metal pollution, particularly lead ion (Pb2 ⁺) contamination, is imperative for safeguarding public health. In this study, we introduced an innovative approach by integrating DNAzyme with rolling circle amplification (RCA) to propose an amplification sensing method termed DNAzyme-based dimeric-G-quadruplex (dimer-G4) RCA. This sensing approach allows for precise and high-fidelity Pb2 ⁺ detection. Strategically, in the presence of Pb2 ⁺, the DNAzyme undergoes substrate strand (S-DNA) cleavage, liberating its enzyme strand (E-DNA) to prime isothermal amplification...

The unique properties of superparamagnetic iron oxide nanoparticles (SPIONs) enable their use as magnetic biosensors, targeted drug delivery, magnetothermia, magnetic resonance imaging, etc. Today, SPIONs are the only type of metal oxide nanoparticles approved for biomedical application. In this work, we analyzed the cellular response to the previously reported luminescent silica coated SPIONs of the two cell types: M-HeLa cells and primary motor neuron culture. Both internalization pathways and intracellular fate of SPIONs have been compared for these cell lines using fluorescence and transmission electron microscopy...

Heteroions doped Ag2 S nanocrystals (NCs) exhibiting enhanced near-infrared-II emission (NIR-II) hold great promise for glioma diagnosis. Nevertheless, current doped Ag2 S NCs paradoxically improved properties via toxic dopants, and the blood-brain barrier (BBB) constitutes another challenge for orthotopic glioma imaging. Thus, it is urgent to develop biofriendly high-bright Ag2 S NCs with active BBB-penetration for glioma-targeted imaging. Herein, bismuth (Bi) was screened to obtain Bi-Ag2 S NCs with high absolute PLQY (∼13...

In recent years, organic-inorganic hybrid materials have demonstrated exceptional performance in nonlinear optics, attracting widespread attention. However, there are relatively few examples of coordination compounds synthesized with Cu as the metal center that exhibit excellent nonlinear optical properties. In this study, we successfully synthesized a pair of enantiomers named R / S -Cu2 I2 by reacting chiral ligands with CuI. The crystal structure reveals a one-dimensional copper-iodide chain structure built by Cu2 I2 clusters, and its ordered arrangement in space provides not only a strong second harmonic generation (SHG) signal (1...

Functional nucleic acids (FNAs) have attracted a lot of attention for the rapid detection of metal ions. Cr3+ is one of the major heavy metal ions in natural waters. Due to the slow ligand exchange rate of Cr3+ , the FNA-based Cr3+ sensors require long assay times, limiting the on-site applications. In this study, we report that the good's buffers containing amino and polyhydroxy groups greatly increase the ligand exchange rate of Cr3+ . Using EDTA as a model coordinate ligand, the Tris buffer (100 mM, pH 7...

On-demand controlled drug release holds great promise for cancer therapy. Light-degradable nanocarriers have gained increasing attention for designing controllable drug delivery systems owing to their spatiotemporally controllable properties. Herein, a highly luminescent and light-degradable nanocarrier is constructed by intercalating glutathione-capped gold nanoclusters (AuNCs) into zeolitic imidazolate framework-8 (ZIF-8) via competitive coordination assembly, named AuNC@ZIF-8, for light-triggered drug release...

The study of photoactive materials often unveils intriguing findings, showcasing the value of an interdisciplinary approach. We examined the purported metal-enhanced luminescence thought to result from the chemisorption of aryl iodides on poly( N -vinylpyrrolidone)-stabilized gold nanoparticles. Our discovery deviates from previous assumptions: the fluorescence observed does not originate from excimers of iodophenols chemisorbed on Au:PVP. Instead, it arises from biphenol products, resulting from a gold-mediated Ullmann homocoupling reaction that occurs within the system...

The CN bond isomerization/modulation as a fluorescence signalling mechanism was explored by studying the photophysical properties of conformationally restricted molecules. From the beginning, the CN bond isomerization method has attracted the attention of researchers owing to its simplicity, high selectivity, and sensitivity in fluorescence evaluation. Continuous developments in the field of sensing using CN bond-containing compounds have been achieved via the customization of the isomerization process around the CN bond in numerous ways, and the results were obtained in the form of specific discrete photophysical changes...

A novel type of chemosensor based on tin(IV) complexes incorporating hydroxyquinoline derivatives has been designed and investigated for selectively detecting fluoride ions. Sn(meq)2 Cl2 (meq = 2-methyl-8-quinolinol) (complex 1) exhibits a significant enhancement in luminescence upon the introduction of fluoride ions. This enhancement greatly surpasses that observed with Snq2 Cl2 and Sn(dmqo)2 Cl2 (q = 8-hydroxyquinnoline; dmqo = 5,7-dimethyl-8-quinolinol). Furthermore, complex 1 displays excellent sensitivity and selectivity for fluoride detection in comparison to halides and other anions...

A new type of two-dimensional layered material, namely C3 N, has been fabricated by polymerization and recommended to have great potential in various applications such as the development of electronic devices or photo-detectors, due to its enhanced conductivity, electronegativity, and unique optical properties. Actually, most of the present research on C3 N is limited in the scope of theoretical calculation, while experimental research is blocked by inefficient synthesis with low purity and homogeneity. Here, we report an optimized efficient synthesis method of high-purity C3 N QDs in aqueous solution by polymerization of DAP with combined centrifugation and filtration of products, with the synthesis yield up to 33...

Our prior studies have illustrated that the uracil ruthenium(II) diimino complex, [Ru(H3 ucp)Cl(PPh3 )] (1) (H4 ucp = 2,6-bis-((6-amino-1,3-dimethyluracilimino)methylene)pyridine) displayed high hypoglycemic effects in diet-induced diabetic rats. To rationalize the anti-diabetic effects of 1, three new derivatives have been prepared, cis-[Ru(bpy)2 (urdp)]Cl2 (2) (urdp = 2,6-bis-((uracilimino)methylene)pyridine), trans-[RuCl2 (PPh3 )(urdp)] (3), and cis-[Ru(bpy)2 (H4 ucp)](PF6 )2 (4). Various physicochemical techniques were utilized to characterize the structures of the novel ruthenium compounds...

Detecting environmental contaminants is crucial for protecting ecosystems and human health. While traditional carbon dot (CD) fluorescent probes are versatile, they may suffer from limitations like fluctuations in signal intensity, leading to detection inaccuracies. In contrast, ratiometric fluorescent probes, designed with internal self-calibration mechanisms, offer enhanced sensitivity and reliability. This review focuses on the design and applications of ratiometric fluorescent probes based on CDs for environmental monitoring...