Selective detection of ferric ions by blue-green photoluminescent nitrogen-doped phenol formaldehyde resin polymer

SMART RHESINs-Superparamagnetic Magnetite Architecture Made of Phenolic Resin Hollow Spheres Coated with Eu(III) Containing Silica Nanoparticles for Future Quantitative Magnetic Particle Imaging Applications

Magnetic particle imaging (MPI) is a powerful and rapidly growing tomographic imaging technique that allows for the non-invasive visualization of superparamagnetic nanoparticles (NPs) in living matter. Despite its potential for a wide range of applications, the intrinsic quantitative nature of MPI has not been fully exploited in biological environments. In this study, a novel NP architecture that overcomes this limitation by maintaining a virtually unchanged effective relaxation (Brownian plus Néel) even when immobilized is presented. This superparamagnetic magnetite architecture made of phenolic resin hollow spheres coated with Eu(III) containing silica nanoparticles (SMART RHESINs) was synthesized and studied. Magnetic particle spectroscopy (MPS) measurements confirm their suitability for potential MPI applications. Photobleaching studies show an unexpected photodynamic due to the fluorescence emission peak of the europium ion in combination with the phenol formaldehyde resin (PFR). Cell metabolic activity and proliferation behavior are not affected. Colocalization experiments reveal the distinct accumulation of SMART RHESINs near the Golgi apparatus. Overall, SMART RHESINs show superparamagnetic behavior and special luminescent properties without acute cytotoxicity, making them suitable for bimodal imaging probes for medical use like cancer diagnosis and treatment. SMART RHESINs have the potential to enable quantitative MPS and MPI measurements both in mobile and immobilized environments.

Near-infrared light-triggered nano-prodrug for cancer gas therapy

Gas therapy (GT) has attracted increasing attention in recent years as a new cancer treatment method with favorable therapeutic efficacy and reduced side effects. Several gas molecules, such as nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), have been employed to treat cancers by directly killing tumor cells, enhancing drug accumulation in tumors or sensitizing tumor cells to chemotherapy, photodynamic therapy or radiotherapy. Despite the great progress of gas therapy, most gas molecules are prone to nonspecific distribution when administered systemically, resulting in strong toxicity to normal tissues. Therefore, how to deliver and release gas molecules to targeted tissues on demand is the main issue to be considered before clinical applications of gas therapy. As a specific and noninvasive stimulus with deep penetration, near-infrared (NIR) light has been widely used to trigger the cleavage and release of gas from nano-prodrugs via photothermal or photodynamic effects, achieving the on-demand release of gas molecules with high controllability. In this review, we will summarize the recent progress in cancer gas therapy triggered by NIR light. Furthermore, the prospects and challenges in this field are presented, with the hope for ongoing development.

Polarity-Sensitive Polymer Carbon Dots Prepared at Room-Temperature for Monitoring the Cell Polarity Dynamics during Autophagy

Taking the advantages of excellent optical properties, biocompatibility, and photostability of carbon dots, herein, we developed polarity-sensitive polymer carbon dots (PCDs) for visualizing of cellular polarity to real-time monitoring autophagy changes without perturbing the cellular status. The PCDs can be prepared by simply mixing dopamine (DA), H₂O₂, and o-phenylenediamine (o-PDA) in a common beaker without the need for any special equipment or external energy supply, and the preparation could be completed within 3 min at room temperature. Interestingly, the polarity-sensitive PCDs could emit various types of fluorescence and are insensitive to the excitation light when dispersed in different water/dioxane systems with different polarities. Based on the polarity-sensitive emission of the PCDs, the change of polarity during autophagy has been successfully monitored in living cells. Moreover, the change of polarity detected by PCDs is autophagy-specific (does not occur during apoptosis), occurs under different autophagy-inducing situations (starvation, rapamycin, and trehalose), and requires a normal autophagic flux, showing that PCDs rapidly prepared by polymerization cross-linking at room temperature can be functionally applied in the case of autophagy-related physiological or pathological processes.

Full-Color Emission Polymer Carbon Dots with Quench-Resistant Solid-State Fluorescence

Polymer carbon dots (PCDs) represent a new class of carbon dots (CDs) possessing sub-fluorophores and unique polymer-like structures. However, like small molecule dyes and traditional CDs, PCDs often suffer from self-quenching effect in solid state, limiting their potential applications. Moreover, it is hard to prepare PCDs that have the same chemical structure, exhibiting full-color emission under one fixed excitation wavelength by only modulating the concentration of the PCDs. Herein, self-quenching-resistant solid-state fluorescent polymer carbon dots (SSFPCDs) are prepared, which exhibit strong red SSF without any other additional solid matrices, while having a large production yield (≈89%) and a considerable quantum yield of 8.50%. When dispersed in water or solid matrices in gradient concentrations, they can exhibit yellow, green, and blue fluorescence, realizing the first SSFPCDs with the same chemical structure emitting in full-color range by changing the ratio of SSFPCDs to the solid matrices.

Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2uptake, redox-activity and oxygen evolution reaction

Remarkable differences in the physicochemical properties of metal–organic gels of Fe(iii) and Al(iii) ions with the TCA ligand is reported.

Germanium nanocrystals as luminescent probes for rapid, sensitive and label-free detection of Fe3+ ions

Luminescent water-soluble germanium nanocrystals (Ge NCs) have been developed as a fluorescent sensing platform for the highly selective and sensitive detection of Fe3+ via quenching of their strong blue luminescence, without the need for analyte-specific labelling groups. The amine-terminated Ge NCs were separated into two discrete size fractions with average diameters of 3.9±0.4 nm and 6.8±1.8 nm using centrifugation. The smaller 3.9 nm NCs possessed a strong blue luminescence, with an average lifetime of 6.1 ns and a quantum yield (QY) of 21.5%, which is strongly influenced by solution pH. In contrast, 6.8 nm NCs exhibited a green luminescence with a longer lifetime of 7.8 ns and lower QY (6.2%) that is insensitive to pH. Sensitive detection of Fe3+ was successfully demonstrated, with a linear relationship between luminescence quenching and Fe3+ concentration observed from 0-800 μM, with a limit of detection of 0.83 μM. The Ge NCs show excellent selectivity toward Fe3+ ions, with no quenching of the fluorescence signal induced by the presence of Fe2+ ions, allowing for solution phase discrimination between ions of the same element with different formal charges. The luminescence quenching mechanism was confirmed by static and time-resolved photoluminescence spectroscopies, while the applicability for this assay for detection of Fe3+ in real water samples was successfully demonstrated.

NIR light controlled release of caged hydrogen sulfide based on upconversion nanoparticles

The first near-infrared light induced H₂S release platform based on upconversion nanoparticles was constructed.