Bimetallic nanostructures can be attractive contrastenhancing materials for dual modal imaging, allowing improved diagnosis ability using two different physical phenomena, following administration of a single nanoagent. In this research, the potential of the biocompatible polydopamine (PDA) was explored as a binding matrix to produce CuO NPs embedded in a PDA matrix (CuO@PDA nanocomposite). PDA was then tested as a reducing agent for both CuO NPs and HAuCl 4 to yield a PDA composite embedded with gold nanoparticles and copper species, readily available for CT-MRI contrast enhancement. Moreover, in vitro cytotoxicity evaluation implied the low cytotoxicity of Au/Cu@PDA nanocomposite. The procedure, characterization, and imaging experiments focused on a representative Au:Cu atomic ratio of 86:14. The resulting longitudinal magnetic relaxation (T1) and X-ray attenuation properties of the nanocomposite are characterized by using phantom experiments and an ex vivo poultry heart model, demonstrating a consistent contrast improvement with both MRI and CT.

Copper oxide nanoparticles (CuO NPs) have anticancer and antimicrobial activities. Moreover, they have a contrast enhancing effect in both MRI and ultrasound. Nonetheless, encapsulation is needed to control their toxic side effects and a mechanism for release on demand is required. A methodology is introduced herein for encapsulating and releasing CuO NPs from micelles by ultrasound induced hyperthermia and monitoring the process by MRI. For this aim, CuO NPs loaded poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles were prepared. Then, the profile of copper release with application of ultrasound was examined as a function of time and temperature using a colorimetric method. Finally, T1 weighted MRI images of suspensions and ex vivo poultry liver samples containing the CuO NPs loaded micelles were acquired before and after ultrasound application. The results confirmed that: (i) encapsulated NPs are detectible by MRI T1 mapping, depicting substantial T1 shortening from 1872 ± 62 ms to 683 ± 20 ms. (ii) Ultrasonic hyperthermia stimulated the NPs release with an about threefold increase compared to non-treated samples. (iii) Releasing effect was clearly visible by T1-weighted imaging (mean signal increase ratio of 2.29). These findings can potentially lead to the development of a new noninvasive methodology for CuO NPs based theranostic process.