pH-triggered drug release from a nanosized metal–organic framework/graphene oxide composite

In pursuit of an effective controlled drug release system, the development of a suitable carrier is crucial. Among many different materials, a combination of graphene oxide (GO) and a metal–organic framework (MOF) shows great potential. Although GO provides good water dispersibility and oxygen-containing functional groups, its drug-loading capacity is insufficient. Conversely, MOF has a tunable pore size and high drug-loading capacity, but suffers from low water solubility and instability in bodily fluids, which limits controlled drug release. Thus, the combined use of GO and MOF is explored to address these challenges. Here, a novel method involving hydrothermal synthesis and ball milling was used to create a nano-size MOF and GO composite (nanoMOF/GO), for use as a drug carrier. Piperine (PI), a hydrophobic drug, was selected for encapsulation, and its loading capacity and release in response to a pH change were evaluated. Results show a high drug loading because of the electrostatic interaction of nanoMOF and GO, forming new pores and binding sites. The release of PI was achieved at pH 5.5, with minimal release observed when using the MOF alone. Furthermore, the inclusion of GO suppressed premature release from the nanoMOF under neutral conditions. Overall, this study highlights the potential of the nanoMOF/GO composite as a promising nanocarrier for drug delivery.