There is intensive research using gold nanoparticles for biomedical purposes, which have many advantages such as ease of synthesis and high reactivity. Their possible small size (<10 nm) can lead to the crossing of biological membranes and then to problematic dissemination and storage in organs that must be controlled and evaluated. In this work, a simple isocratic HPLC method was developed and validated to quantify the gold coming from nanoparticles in different biological samples. After a first carbonization step at 900 °C, the nanoparticles were oxidized by dibroma under acidic conditions, leading to tetrachloroaurate ions that could form ion pairs when adding rhodamine B. Finally, ion pairs were extracted and rhodamine B was evaluated to quantify the corresponding gold concentration by reversed-phase HPLC with visible detection. The method was validated for different organs (liver, spleen, lungs, kidneys, or brain) and fluids (plasma and urine) from rats and mice. Lastly, the developed method was used to evaluate the content of gold in organs and fluids after intravenous (IV) injection of nanoparticles.

In this study, we investigated how the formation and properties of Pickering emulsions (PEs) stabilized by zein/tannic acid particles (ZTAPs) are impacted by the method used to generate the particles, before or during emulsification. ZTAPs were obtained through two antisolvent precipitation methods (sequential and co-precipitation) across zein/tannic acid molar ratio (R) range of 1/0 to 1/30. Emulsions were prepared using four methods, either with pre-formed ZTAPs or by mixing zein and tannic acid immediately before or during emulsification. The results indicated that pre-forming the particles prior to emulsification is crucial for controlling droplet size and homogeneity, while the quantity of tannic acid plays a supporting role. Tannic acid is not only critical for emulsion stabilization but also imparts its antioxidant activity to the emulsions. This activity is also controlled by the molar ratio R of the particles and the preparation protocol. ZTAPs are promising plant-based stabilizers for emulsions in the food and pharmaceutical industries. These findings provide a better understanding of the importance of their method of production in controlling the characteristics (droplet size, stability, and antioxidant properties) of the emulsions they stabilize.

Acute respiratory distress syndrome (ARDS) is characterized by dysregulated pulmonary inflammation involving excessive cytokine production and activation of inflammatory cells, including macrophages. In this study, hybrid lipid–polymer nanoparticles (HLNPBud-siRNA) were developed for the co-delivery of budesonide (Bud) and anti-IL-8/CXCL1 small interfering RNA (siRNA), combining glucocorticoid-mediated anti-inflammatory activity with sequence-specific targeting of a neutrophil-recruiting chemokine pathway. The hybrid nanosystem was assembled from Bud-loaded lipid nanoparticles and polyethyleneimine/siRNA polyplexes, and its physicochemical properties, stability, cellular uptake, biocompatibility, and immunomodulatory activity were evaluated. The optimized formulation exhibited a hydrodynamic diameter of approximately 50 nm, low polydispersity (PDI < 0.2), a negative surface charge (approximately -25 mV), Bud encapsulation efficiency above 90%, and siRNA complexation efficiency above 95%. The formulation maintained its physicochemical characteristics and cargo association were best preserved during refrigerated storage for up to 60 days. In LPS-stimulated RAW 264.7 macrophages, incorporation of PEI/siRNA polyplexes into the hybrid formulation was associated with improved cellular tolerance compared with the corresponding free polyplexes at intermediate concentrations. HLNPBud-siRNA-associated fluorescence was detected intracellularly, and LPS stimulation significantly influenced the temporal profile of nanoparticle-associated cellular fluorescence. Functionally, HLNPBud-siRNA produced greater CXCL1 suppression than the corresponding Bud- and siRNA-containing controls, with the effect becoming more pronounced at 24 h. A marked delayed reduction in TNF-α was also observed, whereas IL-6 suppression was comparable to that produced by the Bud-containing control. At 24 h, Bliss independence analysis showed that the observed inhibition exceeded the predicted independent effects for CXCL1 and TNF-α, but not for IL-6. Overall, these findings demonstrate a mediator- and time-dependent benefit of Bud and anti-CXCL1 siRNA co-delivery and provide proof-of-concept for HLNPBud-siRNA as a hybrid nanoplatform for combined corticosteroid and siRNA delivery.