In this work, bismuth sulfide (Bi₂S₃) thin films were deposited by a chemical bath deposition (CBD) technique (called soft chemistry), while titanium dioxide (TiO₂) nanoparticles were synthesized by sol–gel and zinc oxide (ZnO) nanoparticles were extracted from alkaline batteries. The resulting nanoparticles were then deposited on the Bi₂S₃ thin films by spin coating at 1000 rpm for 60 s each layer to create heterojunctions of Bi₂S₃/ZnO and Bi₂S₃/TiO₂. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The optical and contact angle analyses were undertaken by UV–Vis spectroscopy and a contact microscopy angle meter, respectively. The calculated band gap values were found to be between 1.9 eV and 2.45 eV. The Bi₂S₃ presented an orthorhombic structure, the TiO₂ nanoparticles presented an anatase structure, and the ZnO nanoparticles presented a wurtzite hexagonal crystal structure. Furthermore, heterogeneous solar photocatalysis was performed using the Bi₂S₃, Bi₂S₃/ZnO, and Bi₂S₃/TiO₂ thin film combinations, which resulted in the degradation of Congo red increasing from 8.89% to 30.80% after a 30 min exposure to sunlight.

We present an evaluation of the hardness and Young’s modulus properties of medium pressure sputtered molybdenum disulfide (MoS ₂ ) thin films by applying nano-indentation with continuous stiffness method combined with microstructure analysis using small angle x-ray diffraction, Raman, and an electron microscope in scanning and transmission mode. Our results indicate a vertical growth of MoS ₂ crystallites with stacking values of 7-laminates along the [0 0 1] direction and an average height of 105 nm, principal Raman vibrations at E 2 g 1 at 378 cm ⁻¹ and A _1g at 407 cm ⁻¹ and an interplanar distance of ~0.62 nm as confirmed by high-resolution transmission electron microscopy. An average hardness of H = 10.5 ± 0.1 GPa and elastic modulus of E = 136 ± 2 GPa from 0 to 90 nm of indenter penetration were found in these investigations.

The dressings are materials that can improve the wound-healing process in patients with medical issues. Polymeric films are frequently used as dressings with multiple biological properties. Chitosan and gelatin are the most used polymers in tissue regeneration processes. There are usually several configurations of films for dressings, among which the composite (mixture of two or more materials) and layered ones stand out (layers). This study analyzed the antibacterial, degradable, and biocompatible properties of chitosan and gelatin films in 2 configurations, composite and bilayer, composite. In addition, a silver coating was added to enhance the antibacterial properties of both configurations. After the study, it was found that the bilayer films have a higher antibacterial activity than the composite films, having inhibition halos between 23% and 78% in Gram-negative bacteria. In addition, the bilayer films increased the fibroblast cell proliferation process, reaching up to 192% cell viability after 48 h of incubation. On the other hand, composite films have greater stability since they are thicker, with 276 µm, 243.8 µm, and 239 µm compared to 236 µm, 233 µm, and 219 µm thick for bilayer films; and a low degradation rate compared to bilayer films.

Theranostic agents enable the simultaneous diagnosis and treatment of diseases, and they are particularly useful in fluorescent imaging and cancer therapies. In this study, carbon quantum dots were synthesized via a microwave-assisted method using citric acid and bovine serum albumin (BSA) as precursors. The resulting CQDs exhibited spherical morphology, an average size of 4 nm, and an amorphous graphitic structure. FT-IR characterization revealed the presence of amide bonds and oxygenated functional groups. At the same time, optical analysis showed excitation at 320 nm and emission between 360 and 400 nm, with fluorescent stability maintained for one month. Furthermore, the CQDs demonstrated good thermal stability and photothermal efficiency, reaching temperatures above 41 °C within 15 min under NIR irradiation, with a mass loss of less than 1%. Their stability was evaluated in media with different pH levels, simulating physiological and tumor environments. While their behavior was affected under acidic conditions, their excellent photothermal conversion capacity and overall stability in triple-distilled water positioned them as promising candidates for theranostic applications in cancer, effectively combining diagnostic imaging and thermal therapy.