Highly selective fluorescence detection of Cu2+ based on Schiff base functionalized periodic mesoporous organosilicas

Ratiometric dual-emitting thermometers based on rhodamine B dye-incorporated (nano) curcumin periodic mesoporous organosilicas for bioapplications

This study explores the potential of combining periodic mesoporous organosilicas (PMOs) with a fluorescent dye to develop a ratiometric thermometry system with enhanced stability, sensitivity, and biocompatibility. PMOs, ordered porous materials known for their stability and versatility, serve as an ideal platform. Curcumin, a natural polyphenol and fluorescent dye, is incorporated into PMOs to develop curcumin-functionalized PMOs (C-PMO) and curcumin-pyrazole-functionalized PMOs (CP-PMO) via hydrolysis and co-condensation. These PMOs exhibit temperature-dependent fluorescence properties. The next step involves encapsulating rhodamine B (RhB) dye within the PMO pores to create dual-emitting PMO@dye nanocomposites, followed by a lipid bilayer (LB) coating to enhance biocompatibility and dye retention. Remarkably, within the physiological temperature range, C-PMO@RhB@LB and CP-PMO@RhB@LB demonstrate noteworthy maximum relative sensitivity (Sr) values of up to 1.69 and 2.60% K-1, respectively. This approach offers versatile means to create various ratiometric thermometers by incorporating different fluorescent dyes, holding promise for future temperature sensing applications.

Fluorogen-Functionalized Mesoporous Silica Hybrid Sensing Materials: Applications in Cu2+ Detection

Since Cu2+ ions play a pivotal role in both ecosystems and human health, the development of a rapid and sensitive method for Cu2+ detection holds significant importance. Fluorescent mesoporous silica materials (FMSMs) have garnered considerable attention in the realm of chemical sensing, biosensing, and bioimaging due to their distinctive structure and easily functionalized surfaces. As a result, numerous Cu2+ sensors based on FMSMs have been devised and extensively applied in environmental and biological Cu2+ detection over the past few decades. This review centers on the recent advancements in the methodologies for preparing FMSMs, the mechanisms underlying sensing, and the applications of FMSMs-based sensors for Cu2+ detection. Lastly, we present and elucidate pertinent perspectives concerning FMSMs-based Cu2+ sensors.

Seminaphthorhodafluor Derivatives Bridged Periodic Mesoporous Organosilicas for Detection of Cu2

Seminaphthorhodafluor (SNARF) Schiff base (SNARF-SB) bridged periodic mesoporous organosilicas (SSPMOs) with "turn-on" fluorescence enhancement for sensing Cu²⁺ were synthesized via a template-directed co-condensation method. Small-angle x-ray scattering (SAXS) patterns, high resolution transmission electron microscope (HRTEM) images, and N₂ adsorption-desorption isotherms indicated the presence of mesoporous structure in the SSPMOs. FT-IR spectra and ²⁹Si MAS NMR data confirmed the successful incorporation of bridged organic groups in the framework of SSPMOs. The luminous properties that SSPMOs had a selective response to Cu²⁺ were investigated by UV-Vis absorption spectroscopy and fluorescence spectroscopy. The limit of detection (LOD) was 5.1 × 10^-7 M and binding stoichiometry was determined 1:1 between SNARF-SB and Cu²⁺. The fluorescence enhancement of SSPMOs towards Cu²⁺ was induced by ring-opening of the spirolactam in SNARF-SB in framework of SSPMOs, which was confirmed by FT-IR spectra of SNARF-SB with Cu²⁺. Moreover, SSPMOs have improved fluorescence lifetimes compared with that of SNARF-SB. Therefore, SSPMOs can be a progressive chemical sensor for Cu²⁺ due to its high selectivity, recyclability, and stability.

Ultrasmall organosilica nanoparticles with strong solid-state fluorescence for multifunctional applications

INTRODUCTION

Organosilica nanoparticles (ONs), which are a new type of photoluminescent nanomaterial (PM) with excellent biocompatibility, have caught more attention in recent years. However, their applications are significantly impeded by the complicated preparation process, poor photostability, and especially aggregation-induced quenching.

OBJECTIVES

The present study was aimed to design and prepare solid-state fluorescent ONs to avoid aggregation-induced quenching effect. In addition, the uses of ONs for fingerprint detection, white light-emitting diodes (WLEDs) and lysosome-targetable cellular imaging were demonstrated.

METHODS

Here, for the first time, we designed and prepared novel solid-state fluorescent ultrasmall ONs with orange-emitting photoluminescence via a one-step hydrothermal method.

RESULTS

The prepared solid-state fluorescent ONs could be successfully employed in fingerprint detection, WLEDs fabrication and cellular imaging. Intriguingly, the ultrasmall ONs specifically localized to lysosomes rather than other subcellular organelles across distinct cell lines, including cancer cells and noncancerous cells.

CONCLUSION

Collectively, these data showed that the new ONs presented in this study could be ideal candidates for PMs in biological and photoelectric applications.

A Chemosensor of 1,8-Dihydroxyanthraquinone PMOs Prepared in a Ternary Deep Eutectic Solvent for the Sensitive Detection of Cu2

A novel type of organic-inorganic hybrid periodic mesoporous materials based on 1,8-dihydroxyanthraquinone (DHAQ-PMOs) was synthesized in a ternary deep eutectic solvent (DES). In the process of the material synthesis, an organosiloxane precursor (DHAQ-Si) and tetraethylorthosilicate (TEOS) were used as the mixed Si source, and cetyltrimethylammonium bromide (CTAB) was used as the structure directing agent. The DES formed by choline chloride (ChCl), urea (U), and ethylene glycol (EG) was used as a green solvent. The water needed for the hydrolysis of DHAQ-Si and TEOS was provided from free water in the sodium hydroxide solution. As characterized by small-angle X-ray scattering, nitrogen adsorption/desorption isotherms, and high-resolution transmission electron microscopy, the obtained mesoporous materials exhibit a two-dimensional hexagonal (P6mm) structure. DHAQ possesses double fluorescence emission peaks at ca. 520 and 580 nm due to the effect of the excited-state intramolecular proton transfer (ESIPT). For DHAQ-PMOs, the silica framework can provide a rigid environment that makes the fluorescence properties more stable and the fluorescence emission peak appears to red-shift obviously. The DHAQ-PMOs have high selectivity and sensitivity in a wide pH range that can be used to detect Cu²⁺, and the limit of detection (LOD) is as low as 2.39 × 10^-9 M. Fluorescence polarization experiments, high-resolution mass spectrometry, and Fourier transform infrared spectroscopy were used to study the coordination interaction between DHAQ and Cu²⁺. The density functional theory (DFT) was used to further prove the coordination ability and interaction between DHAQ and Cu²⁺. XPS spectra were also done to prove the coordination of DHAQ and DHAQ-PMO-10 with Cu²⁺. In addition, confocal fluorescence microscope images exhibit that DHAQ-PMOs can detect Cu²⁺ in living cells. The results show that DHAQ-PMOs have great application potential as a sensor for the detection of Cu²⁺.

Interfacially Super-Assembled Benzimidazole Derivative-Based Mesoporous Silica Nanoprobe for Sensitive Copper (II) Detection and Biosensing in Living Cells

Mesoporous silica nanoparticles (MSNs) functionalized with benzimidazole-derived fluorescent molecules (DHBM) are fabricated via a feasible interfacial superassembly strategy for the highly sensitive and selective detection of Cu²⁺ . DHBM-MSN exhibits an obvious quenching effect on Cu²⁺ in aqueous solutions, and the detection limit can be as low as 7.69×10^-8  M. The DHBM-MSN solid-state sensor has good recyclability, and the silica framework can simultaneously improve the photostability of DHBM. Two mesoporous silica nanoparticles with different morphologies were specially designed to verify that nanocarriers with different morphologies do not affect the specific detectionability. The detection mechanism of the fluorescent probe was systematically elucidated by combining experimental results and density function theory calculations. Moreover, the detection system was successfully applied to detect Cu²⁺ in bovine serum, juice, and live cells. These results indicate that the DHBM-MSN fluorescent sensor holds great potential in practical and biomedical applications.