Design, Synthesis, and Evaluation of Near-Infrared Fluorescent Molecules Based on 4H-1-Benzopyran Core

A series of novel fluorescent 4H-1-benzopyrans was designed and developed as near-infrared fluorescent molecules with a compact donor–acceptor-donor architecture. Spectral intensity of the fluorescent molecules M-1, M-2, M-3 varied significantly with the increasing polarities of solvents, where M-3 showed high viscosity sensitivity in glycerol-ethanol system with a 3-fold increase in emission intensity. Increasing concentrations of compound M-3 to 5% BSA in PBS elicited a 4-fold increase in fluorescence intensity, exhibiting a superior environmental sensitivity. Furthermore, the in vitro cellular uptake behavior and CLSM assay of cancer cell lines demonstrated that M-3 could easily enter the cell nucleus and bind to proteins with low toxicity. Therefore, the synthesized near-infrared fluorescent molecules could provide a new direction for the development of optical imaging probes and potential further drugs.

Improvement of Drug-Loading Properties of Hydroxyapatite Particles Using Triethylamine as a Capping Agent: A Novel Approach

Particles that modify delivery characteristics are a focus of drug-loading research. Hydroxyapatite particles (HAPs) have excellent biocompatibility, shape controllability, and high adsorption, making them a potential candidate for drug-delivery carriers. However, there are still some defects in the current methods used to prepare HAPs. In order to avoid agglomeration and improve the drug-loading properties of HAPs, the present study provides a novel triethylamine (TEA)-capped coprecipitation template method to prepare HAPs at room temperature. In addition, pure water and anhydrous ethanol were used as solvents to investigate the capping effect of the small-molecule capping agent TEA during the synthesis of HAPs. The results showed that the HAPs prepared in the TEA ethanol system had a smaller particle size (150–250 nm), better dispersion and higher crystallinity. The results were significantly different from those of the conventional preparation methods without TEA. However, the hydroxyapatite crystal would agglomerate to a certain extent after being stored for a period of time, forming micro/nano-sized agglomerates of nanocrystals. FITR analysis and SEM observation showed that the capping effect of TEA promoted the formation of a smaller template and dispersed HAPs were quickly formed by dissolution and reprecipitation processes. The drug-loading experiments showed that the HAPs prepared in the TEA ethanol system had high drug-loading capacity (239.8 ± 13.4 mg·g−1) as well as an improved drug-release profile demonstrated in the drug-release experiment. The larger specific surface area associated with the smaller particle size was beneficial to the adsorption of drugs. After drying at 60 °C, TEA was evaporated from the HAPs which agglomerated into larger micron particles with more drug encapsulated. Thus, the effect of a sustained release was achieved. In the present research, a novel approach was developed by using triethylamine as the capping agent to prepare micro/nano-sized agglomerates of HAP nanocrystals with improved drug loading, which is predicted to have potential application in drug delivery.

Thermal Traits of MNPs under High-Frequency Magnetic Fields: Disentangling the Effect of Size and Coating

We investigated the heating abilities of magnetic nanoparticles (MNPs) in a high-frequency magnetic field (MF) as a function of surface coating and size. The cobalt ferrite MNPs were obtained by a hydrothermal method in a water–oleic acid–ethanol system, yielding MNPs with mean diameter of about 5 nm, functionalized with the oleic acid. By applying another cycle of hydrothermal synthesis, we obtained MNPs with about one nm larger diameter. In the next step, the oleic acid was exchanged for 11-maleimidoundecanoic acid or 11-(furfurylureido)undecanoic acid. For the heating experiments, all samples were dispersed in the same solvent (dichloroethane) in the same concentration and the heating performance was studied in a broad interval of MF frequencies (346–782 kHz). The obtained results enabled us to disentangle the impact of the hydrodynamic, structural, and magnetic parameters on the overall heating capabilities. We also demonstrated that the specific power absorption does not show a monotonous trend within the series in the investigated interval of temperatures, pointing to temperature-dependent competition of the Brownian and Néel contributions in heat release.

Synthesis of hierarchical porous Prussian blue analogues in partially miscible ionic liquid/ethanol solution near the phase boundary

A new strategy of synthesize hierarchical porous Prussian blue analogues using the nanodomains as the template in partially miscible ionic liquid/ethanol system, especially near the phase boundary, and pore size...