Biocompatible and biodegradable copper-protocatechuic metal-organic frameworks as rifampicin carrier

Tuberculosis (TB) is a disease caused by the M. tuberculosis bacteria infection and is listed as one of the deadliest diseases to date. Despite the development of antituberculosis drugs, the need for long-term drug consumption and low patient commitment are obstacles to the success of TB treatment. A continuous drug delivery system that has a long-term effect is needed to reduce routine drug consumption intervals, suppress infection, and prevent the emergence of drug-resistant strains of M. tuberculosis. For this reason, biomolecule metal-organic framework (BioMOF) with good biocompatibility, nontoxicity, bioactivity, and high stability are becoming potential drug carriers. This study used a bioactive protocatechuic acid (PCA) as organic linker to prepare copper-based BioMOF Cu-PCA under base-modulated conditions. Detailed crystal analysis by the powder X-ray diffraction demonstrated that the Cu-PCA, with a chemical formula of C₁₄H₁₆O₁₃Cu₃, crystalizes as triclinic in space group P1. Comprehensive physicochemical characterizations were provided using FTIR, SEM, XPS, TGA, EA, and N₂ sorption. As a drug carrier, Cu-PCA showed a high maximum rifampicin (RIF) drug loading of 443.01 mg/g. Upon resuspension in PBS, the RIF and linkers release profile exhibited two-stage release kinetic profiles, which are well described by the Biphasic Dose Response (BiDoseResp) model. A complete release of these compounds (RIF and PCA) was achieved after ~9 h of mixing in PBS. Cu-PCA and RIF@Cu-PCA possessed antibacterial activity against Escherichia coli, and good biocompatibility is evidenced by the high viability of MH-S mice alveolar macrophage cells upon supplementations.