Facile Ultrasound-Triggered Release of Calcein and Doxorubicin from Iron-Based Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are promising new nanocarriers with potential use in anticancer drug delivery. However, there is a scarcity of studies on the uptake and release of guest molecules associated with MOF nanovehicles, and their mechanism is poorly understood. In this work, newly developed iron-based MOFs, namely Fe-NDC nanorods, were investigated as potential nanocarriers for calcein (as a model drug/dye) and Doxorubicin (a chemotherapeutic drug (DOX)). Calcein was successfully loaded by equilibrating its solution with the MOFs nanoparticles under constant stirring. The calcein average encapsulation efficiency achieved was 43.13%, with a corresponding capacity of 17.74 wt.%. In-vitro calcein release was then carried out at 37°C in phosphate buffer saline (PBS) using ultrasound (US) as an external trigger. MOFs released an average of 17.8% (without US), whereas they released up to 95.2% of their contents when 40-kHz US at ~1 W/cm² was applied for 10 min. The Cytotoxic drug DOX was also encapsulated in Fe-NDC, and its In-vitro release profile was determined under the same conditions. DOX encapsulation efficiency and capacity were found to be 16.10% and 13.37 wt.%, respectively. In-vitro release experiments demonstrated significant release, reaching 80% in 245 minutes, under acoustic irradiation, compared to around 6% in the absence of US. Additionally, experimental results showed that Fe-NDC nanoparticles are biocompatible even at relatively high concentrations, with an MCF-7 IC₅₀ of 1022 g/ml. Our work provides a promising platform for anticancer drug delivery by utilizing biocompatible Fe-NDC nanoparticles and US as an external trigger mechanism.