RESUMEN
The remarkable applicability and unique properties of CdTe nanoparticles make them vital in various applications such as optoelectronics and photovoltaics. It has been demonstrated that adding a metal dopant to a nanomaterial matrix significantly improves its characteristics, increasing its potential for a variety of applications. In this work, a simple hydrothermal synthesis process for bidoped CdTe nanoparticles is reported, wherein four distinct samples are generated by adjusting the concentration of Bi doping. Structural analysis using X-ray diffraction (XRD) confirmed the presence of the CdTe cubic phase in the material with observable phase shifts due to Bi incorporation. Rietveld refinement of the XRD results further enabled a detailed structural analysis. Raman spectroscopy provided insights into the different vibrational modes of CdTe, while transmission electron microscopy analysis further elucidated the CdTe phase and determined interplanar spacing values. Morphological examination via field emission scanning electron microscopy revealed a consistent nanoparticle-like morphology, unaffected even by increased Bi concentration. Elemental analysis conducted through inductively coupled plasma mass spectrometry offered valuable insights into the composition of the material. Furthermore, UV-vis analysis revealed a decrease in the bandgap, indicating potential shifts in the material's optical properties. Notably, the photoresponse study demonstrated an increase in current value, as well as alterations in the rise and decay times of the material. These properties highlight its potential for various optical and electrical applications. Overall, these findings underscore the promising prospects of bidoped CdTe nanoparticles in various advancements.
RESUMEN
Macrophages eliminate and destroy invading bacteria and contaminants by engulfing them or secreting cytokines that trigger downstream immune responses. Consequently, impairment of the phagocytic functions of macrophages and/or suppressing their cytokine secretion are dangerous to organisms that rely on immune protection. Accordingly, exposure to environmental nanoparticles (NPs) that display immunomodulatory properties are serious. In this work, two types of NPs, i.e., mild-toxicity CuInS2 NPs and high-toxicity CdTe NPs, were used to evaluate the effects of NP exposure for macrophages. Following incubation for 24 h, THP-1-derived macrophage viability was assessed using an MTT method after exposing the THP-1 cells to different concentrations of CuInS2 or CdTe NPs. Phagocytosis assays demonstrated that both CuInS2 and CdTe NPs impair phagocytic activity toward Staphylococcus aureus (S. aureus). After pretreatment with CuInS2 and CdTe NPs at 4 µmol/L, THP-1 macrophages exhibited decreases in phagocytic ratio from ca. 32.9% to ca. 18.5% and 18.7%, respectively. Since the zeta potentials of intact and weathered CuInS2 NPs were distributed over a wide range from positive to negative, large quantities of intact and weathered CuInS2 NPs bore sufficient positive charge on their surfaces to induce membrane depolarization, thus theoretically providing electrostatic forces between S. aureus and THP-1, which could induce downstream intracellular events that increase phagocytosis. However, real time polymerase chain reaction arrays revealed that transcription of the pro-inflammatory factors IL-1ß, IL-6, and TNF-α decreased while that of the anti-inflammatory factor IL-10 increased after treatment with CuInS2 NPs. Furthermore, transcription of TNF-α decreased while IL-10 increased after treatment with CdTe NPs. Thus, both kinds of NPs inhibited phagocytosis of S. aureus by THP-1 to some extent, confirming that immunosuppression can occur when macrophages are exposed to environmental NPs.