Nanostructured titanium dioxide (TiO₂) has a potential platform for the removal of organic contaminants, but it has some limitations. To overcome these limitations, we devised a promising strategy in the present work, the heterostructures of TiO₂ sensitized by molybdenum disulfide (MoS₂) nanoflowers synthesized by the mechanochemical route and utilized as an efficient photocatalyst for methyl orange (MO) degradation. The surface of TiO₂ sensitized by MoS₂ was comprehensively characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform–infrared spectroscopy (FT–IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence spectroscopy (PL), Brunauer–Emmett–Teller (BET) surface area, and thermogravimetric analysis (TGA). From XRD results, the optimized MoS₂–TiO₂ (5.0 wt %) nanocomposite showcases the lowest crystallite size of 14.79 nm than pristine TiO₂ (20 nm). The FT–IR and XPS analyses of the MoS₂–TiO₂ nanocomposite exhibit the strong interaction between MoS₂ and TiO₂. The photocatalytic results show that sensitization of TiO₂ by MoS₂ drastically enhanced the photocatalytic activity of pristine TiO₂. According to the obtained results, the optimal amount of MoS₂ loading was assumed to be 5.0 wt %, which exhibited a 21% increment of MO photodegradation efficiency compared to pristine TiO₂ under UV–vis light. The outline of the overall study describes the superior photocatalytic performance of 5.0 wt % MoS₂–TiO₂ nanocomposite which is ascribed to the delayed recombination by efficient charge transfer, high surface area, and elevated surface oxygen vacancies. The context of the obtained results designates that the sensitization of TiO₂ with MoS₂ is a very efficient nanomaterial for photocatalytic applications.

Zeolite imidazolate framework-8 (ZIF8) represents a class of highly porous materials with a very high surface area, large pore volume, thermal stability, and biocompatibility. In this study, ZIF8-based nanostructures demonstrated a high loading capacity for doxorubicin (62 mg Dox per g ZIF8) through the combination of π–π stacking, hydrogen bonding, and electrostatic interactions. Dox-loaded ZIF8 was subsequently decorated with polyacrylic acid (PAA) (ZIF8–Dox@PAA) that showed good dispersity, fluorescent imaging capability, and pH-responsive drug release. The stable localization and association of Dox in ZIF8@PAA were investigated by C¹³ nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy. The NMR chemical shifts suggest the formation of hydrogen bonding interactions and π–π stacking interactions between the imidazole ring of ZIF8 and the benzene ring of Dox that can significantly improve the storage of Dox in the ZIF8 nanostructure. Additionally, the release mechanism of ZIF8–Dox@PAA was discussed based on the detachment of the PAA layer, enhanced solubility of Dox, and destruction of ZIF8 at different pH conditions. In vitro release test of ZIF8–Dox@PAA at pH 7.4 showed the low release rate of 24.7% even after 100 h. However, ZIF8–Dox@PAA at pH 4.0 exhibited four stages of release profiles, significantly enhanced release rate of 84.7% at the final release stage after 30 h. The release kinetics of ZIF8–Dox@PAA was analyzed by the sigmoidal Hill, exponential Weibull, and two-stage BiDoseResp models. The ZIF8–Dox@PAA nanocarrier demonstrated a promising theranostic nanoplatform equipped with fluorescent bioimaging, pH-responsive controlled drug release, and high drug loading capacity.

Accurate and rapid blood-based detection of dopamine levels can aid in the diagnosis and monitoring of diseases related to dopaminergic dysfunction. For the sensitive detection of dopamine levels in human blood plasma (i.e., plasma dopamine levels), a silver-plated Au bimetallic nanocluster (so called plasmonic Au/Ag nanocluster) was prepared as a surface-enhanced Raman scattering (SERS) substrate by the combination of electrodeposition and electroless plating methods. The plasmonic effect of the Au/Ag nanocluster substrate was optimized by controlling the particle morphology, packing density, and interparticle distance, showing the best performance in its SERS activity. The lowest detection limit of dopamine was ∼10⁻¹¹ M. A linear standard curve was obtained by plotting the log-scale of dopamine concentration (log C) versus Raman intensity at 1152 cm⁻¹. The optimized SERS substrate quantified the plasma dopamine levels of patients with antipsychotic drug-induced Parkinsonism (n = 15) as 3.24 × 10⁻⁹ M and healthy control subjects (n = 15) as 2.31 × 10⁻⁸ M. Patients with drug-induced Parkinsonism had ∼86% lower plasma dopamine concentration than healthy subjects (two-tailed p-value = 0.000002), indicating a clear separation between the groups. Our study provides the first report on the quantitative SERS detection of dopamine levels in human blood plasma with Parkinsonism. The results highlight the potential clinical utility of the optimized SERS technique in screening clinical populations with dopaminergic dysfunction, i.e., differentiating between healthy subjects and patients with Parkinsonism.

This study explores the facile, template-free synthesis of S-doped g-C₃N₄ pinhole nanosheets (SCNPNS) with porous structure for fluorescence sensing of Ag⁺ ions and visible-light photocatalysis of dyes. As-synthesized SCNPNS samples were characterized by various analytical tools such as XRD, FT-IR, TEM, BET, XPS, and UV–vis spectroscopy. At optimal conditions, the detection linear range for Ag⁺ was found to be from 0 to 1000 nM, showing the limit of detection (LOD) of 57 nM. The SCNPNS exhibited highly sensitive and selective detection of Ag⁺ due to a significant fluorescence quenching via photo-induced electron transfer through Ag⁺–SCNPNS complex. Moreover, the SCNPNS exhibited 90% degradation for cationic methylene blue (MB) dye within 180 min under visible light. The enhanced photocatalytic activity of the SCNPNS was attributed to its negative zeta potential for electrostatic interaction with cationic dyes, and the pinhole porous structure can provide more active sites which can induce faster transport of the charge carrier over the surface. Our SCNPNS is proposed as an environmental safety tool due to several advantages, such as low cost, facile preparation, selective recognition of Ag⁺ ions, and efficient photocatalytic degradation of cationic dyes under visible light.

Multifunctional mesoporous silica nanoparticles (MSNs) can confer dynamically varied release kinetics depending on the intermolecular interactions between model drugs and functional decorations on the MSNs.