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pH-Responsive Metal-Organic Framework Thin Film for Drug Delivery
Steven G Guillen1, Jacob Parres-Gold2, Angel Ruiz1
1Department of Chemistry and Biochemistry, California State University Long Beach, 1250 Bellflower Boulevard, Long Beach, California90840, United States.
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.
Insights
This study shows that MIL-88B(Fe) metal-organic framework films can release ibuprofen in response to pH changes. These films show potential for targeted drug delivery in acidic environments like tumors.
Area of Science:
- Materials Science
- Nanotechnology
- Drug Delivery
Background:
- Metal-organic frameworks (MOFs) offer tunable properties for advanced applications.
- pH-responsive materials are crucial for targeted drug delivery systems.
- MIL-88B(Fe) is a promising MOF material with potential for stimuli-responsive behavior.
Purpose of the Study:
- To investigate the pH-responsive drug release capabilities of surface-supported MIL-88B(Fe) thin films.
- To quantify the drug loading capacity and release kinetics of MIL-88B(Fe) films.
- To evaluate the potential of MIL-88B(Fe) as a pH-triggered drug delivery system.
Main Methods:
- Fabrication of surface-supported MIL-88B(Fe) thin films.
- Real-time monitoring of film behavior using surface plasmon resonance microscopy.
- Quantification of ibuprofen loading using quartz crystal microbalance (QCM).
- Assessment of drug release profiles under acidic (pH 6.3) and neutral (pH 7.4) conditions using QCM.
Main Results:
- MIL-88B(Fe) films demonstrated significantly higher dissociation rates in acidic conditions (pH 6.3) compared to neutral conditions (pH 7.4).
- The films exhibited an ibuprofen loading capacity of approximately 6.0 μg/cm2.
- Drug release was substantially higher in acidic environments over a 55-hour period, attributed to pH-sensitive bond breaking.
Conclusions:
- MIL-88B(Fe) thin films function as effective pH-triggered drug delivery systems.
- The observed pH-sensitivity is linked to the dissociation of Fe3+-carboxylate bonds.
- These findings highlight the potential of MOF thin films for targeted therapeutic applications in acidic disease microenvironments.
