Nanomaterials

Multimodal nanocomposites that combine optical and magnetic functionalities are of great interest for applications such as imaging and temperature sensing. Ternary CuInS₂ (CIS)-based quantum dots (QDs) offer low toxicity, strong near-infrared (NIR) emission, and high photostability, making them promising for optical nanothermometry and imaging. In this study, CIS QDs were synthesized using an aqueous cysteine-mediated approach. Manganese ferrite (MnFe₂O₄) nanoparticles were prepared as the magnetic component due to their non-toxicity and superparamagnetic properties. To integrate both functionalities, QDs and magnetic nanoparticles (MNPs) were encapsulated in silica and then combined to form multimodal CIS/MnFe₂O₄/SiO₂ nanocomposites. The structure and morphology of the materials were characterized by TEM and XRD, while their optical properties were examined using UV–Vis, photoluminescence (PL) spectroscopy. This design ensured optical isolation, preventing fluorescence quenching while maintaining colloidal stability. The obtained composites exhibited PL in the NIR region and a thermosensitivity of 2.04%/°C. TEM analysis confirmed uniform silica shell formation and successful integration of both components within the composite. The materials also retained the superparamagnetic behavior of MnFe₂O₄, making them suitable for combined optical and magnetic functionalities. These results demonstrate the potential of CIS/MnFe₂O₄/SiO₂ nanocomposites as multifunctional platforms for optical imaging, temperature monitoring, and magnetically modulated effects.

Femtosecond laser-ablated gold nanoparticles (AuNPs) offer a unique platform for developing novel cost-effective contrast agents due to their ultraclean, surfactant-free synthesis and precisely tunable surface properties. This study developed three computed tomography (CT) contrast agents from a single stock solution of laser-ablated AuNPs, functionalized with polyethylene glycol (PEG-2kDa, PEG-4kDa), or lipoic acid with bovine serum albumin (BSA). The primary objective was to evaluate the safety and functional efficacy of these coated AuNPs in healthy and tumor-bearing mice. After a single intravenous injection (690 ± 30 mg Au/kg), all formulations were well tolerated with no acute toxicity observed. PEGylated AuNPs demonstrated long blood half-life (18 ± 2 h for PEG-2kDa; 37 ± 2 h for PEG-4kDa), making them suitable for cardiovascular imaging up to 24 h post-injection. BSA-AuNPs had a rapid blood clearance (T_1/2 = 2.8 ± 0.9 h), permitting cardiovascular assessment during the first 3 h, and provided intense, persistent contrast in abdominal organs, enabling liver imaging from 5 min and spleen imaging from 1 h post-injection. In a Ca755 mammary adenocarcinoma model, PEGylated AuNPs selectively accumulated in the tumor stroma and fibrous septa, allowing for precise tumor margin delineation and analysis of internal architecture. The findings establish that a single AuNP stock can be used to produce specialized contrast agents for specific imaging applications.

This work presents a facile mechano-thermal route for the synthesis of carbon-decorated, hollow, mesoporous α-Fe₂O₃ microspheres. Comprehensive characterization (XRD, XPS, FT-IR, SEM/EDX, TGA, zeta-potential) confirmed the formation of phase-pure hematite with nanoscale crystallites (~19 nm), substantial residual surface carbon (~40 wt%) consistent with Fe–O–C linkages, and a positive surface charge (+15.9 mV). The hierarchical hollow/mesoporous architecture enables fast ion transport and provides extensive interior binding sites, resulting in rapid Pb(II) uptake that reaches 92% removal in ≈15 min at pH 5.0. The adsorption follows a Langmuir isotherm (q_max ≈ 70.6 mg/g) and pseudo-second-order kinetics, indicative of chemisorption coupled to efficient mass transfer into internal sites. The composite also exhibits antibacterial activity against Escherichia coli and Staphylococcus aureus, demonstrating its potential for simultaneous mitigation of heavy metal contaminants and pathogens.