Zinc oxide (ZnO) and iron oxide (IO) nanoparticles have been identified as promising candidates for biomedical applications, based on their unique physicochemical properties. The association of these nanoparticles in a single system creates a bimodal entity, allowing the excellent luminescent properties of ZnO quantum dots to be combined with the contrast agent of IO for magnetic resonance imaging (MRI). The present study focuses on the luminescent and MRI properties of a new poly(lactic-co-glycolic acid) (PLGA) nanocarrier system formulation containing ZnO NPs and IO NPs in different nominal ratios. Microscopic analysis (TEM and SEM) reveals a circular morphology with IO and ZnO NPs. The average diameter of the particles was determined to be 220 nm, as measured by DLS. The luminescence results indicate that the PLGA system shows strong emission in the visible range, and the MRI analysis shows a high r2 relaxivity of 171 mM⁻¹ s⁻¹ at 7T. The optimized formulation, exhibiting a molar ratio of Fe:Zn ranging from 1:10 to 1:13 (mol:mol), demonstrates superior fluorescence and MRI performance, underscoring the significance of nanoparticle composition in bimodal imaging applications. The systems evaluated demonstrate no toxicity in the THP-1 cells for doses of up to 128 µg mL⁻¹, with efficient labeling after 4 h of incubation, yielding images of strong luminescence and T2 contrast. The PLGA:ZnO:IO system demonstrates considerable potential as a bimodal platform for diagnostic imaging.

This study aimed to develop and characterize thermoresponsive bioinks based on Poloxamer 407 (P407) at different concentrations (20%, 25%, and 30%), modified with polyvinylpyrrolidone (PVP K30 and K90, 0.5 and 1%), alginate (3.85%), and gelatin (3.85%), and incorporated with zinc oxide nanoparticles (ZnO-NPs). The formulations were evaluated in terms of rheological properties, 3D printing performance, and post-printing drying behavior. Rheological analysis showed that P407 hydrogels at 25% and 30% exhibited pseudoplastic and thixotropic behavior, suitable for 3D printing, whereas formulations with ≤ 20% behaved as Newtonian fluids and were excluded. Drying tests revealed that the addition of PVP reduced the volume loss rate by up to 35% after 72 hours compared to pure P407, while alginate and gelatin improved the preservation of the printed cylindrical shape and reduced cracking. The incorporation of ZnO-NPs further enhanced water retention and structural stability. These findings highlight the potential of P407-based bioinks (25–30%) combined with functional additives and ZnO-NPs for biomedical applications requiring structural stability and precise printing behavior.