pH-Responsive Metal–Organic Framework Thin Film for Drug Delivery

Abstract

In this work, surface-supportive MIL-88B(Fe) was explored as a pH-stimuli thin film to release ibuprofen as a model drug. We used surface plasmon resonance microscopy to study the pH-responsive behaviors of MIL-88B(Fe) film in real time. A dissociation constant of (6.10 ± 0.86) × 10–3 s–1 was measured for the MIL-88B(Fe) film in an acidic condition (pH 6.3), which is about 10 times higher than the dissociation of the same film in a neutral pH condition. MIL-88B(Fe) films are also capable of loading around 6.0 μg/cm2 of ibuprofen, which was measured using a quartz crystal microbalance (QCM). Drug release profiles were compared in both acidic and neutral pH conditions (pH 6.3 and 7.4) using a QCM cell to model the drug release in healthy body systems and those containing inflammatory tissues or cancerous tumors. It was found that the amount of drug released in acidic environments had been significantly higher compared to that in a neutral system within 55 h of testing time. The pH-sensitive chemical bond breaking between Fe3+ and the carboxylate ligands is the leading cause of drug release in acidic conditions. This work exhibits the potential of using MOF thin films as pH-triggered drug delivery systems.

Metal–Organic Frameworks for Cisplatin Delivery to Cancer Cells: A Molecular Dynamics Simulation

“…42 By incorporating pH-sensitive ligands, these MOFs remain stable in the neutral pH environment of the bloodstream and selectively release encapsulated drugs at target sites characterized by slightly acidic pH, such as tumor tissues. 41 This pH-triggered drug release strategy enhances drug bioavailability and reduces off-target effects, offering a potential solution to combat drug resistance and enhance patient outcomes. 41 However, MOFs are hampered by high production costs and low stability, posing challenges for their study as drug delivery systems.…”

“…In the realm of drug delivery, pH-responsive MOFs offer a promising strategy for improving drug efficacy while minimizing side effects . By incorporating pH-sensitive ligands, these MOFs remain stable in the neutral pH environment of the bloodstream and selectively release encapsulated drugs at target sites characterized by slightly acidic pH, such as tumor tissues . This pH-triggered drug release strategy enhances drug bioavailability and reduces off-target effects, offering a potential solution to combat drug resistance and enhance patient outcomes …”

“…Also, MOFs exhibit a distinctive characteristic of undergoing reversible structural changes in response to varying pH conditions. The organic ligands within pH-responsive MOFs incorporate functional groups capable of protonation or deprotonation in response to pH changes. , This dynamic nature allows pH-responsive MOFs to selectively adsorb or release guest molecules, making them highly attractive for controlled drug delivery systems. In the realm of drug delivery, pH-responsive MOFs offer a promising strategy for improving drug efficacy while minimizing side effects .…”

“…41 This pH-triggered drug release strategy enhances drug bioavailability and reduces off-target effects, offering a potential solution to combat drug resistance and enhance patient outcomes. 41 However, MOFs are hampered by high production costs and low stability, posing challenges for their study as drug delivery systems. 39 Moreover, there is a lack of data and research regarding MOFs' permeation through cancer cell membranes at the molecular level.…”

“… 41 This pH-triggered drug release strategy enhances drug bioavailability and reduces off-target effects, offering a potential solution to combat drug resistance and enhance patient outcomes. 41 …”