Zeolitic Imidazole Framework (ZIF) Nanospheres for Easy Encapsulation and Controlled Release of an Anticancer Drug Doxorubicin under Different External Stimuli: A Way toward Smart Drug Delivery System

Abstract

The conventional drug delivery systems made from organic- or inorganic-based materials suffer from some problems associated with uncontrolled drug release, biocompatibility, cytotoxicity, and so forth. To overcome these problems, zeolitic imidazole framework (ZIF) hybrid materials can be one of the solutions. Here, we report a very easy and successful encapsulation of an anticancer drug doxorubicin inside two ZIFs, namely, ZIF-7 and ZIF-8, which are little explored as drug delivery systems, and we studied the controlled release of the drug from these two ZIFs under external stimuli such as change in pH and upon contact with biomimetic systems. Experimental results demonstrate that ZIF-7 remains intact when the pH changes from physiological condition to acidic condition, whereas ZIF-8 successfully releases drug under acidic condition. Interestingly, both the ZIFs are excellent for drug release when they come in contact with micelles or liposomes. In the case of ZIF-8, the drug delivery can be controlled for 3 h, whereas its analogue ZIF-7 delivers the drug for a time span of 10 h. We explained the reluctance of ZIF-7 toward drug release in terms of rigidity. This study highlights that by using different ZIFs and liposomes, the drug release rate can be easily modulated, which implies ample possibility for ZIFs as a good drug delivery system. The study shows a novel strategy for easy drug encapsulation and its release in a controlled manner, which will help future development of the drug delivery system.

Metal–Organic Framework‐Based Stimuli‐Responsive Systems for Drug Delivery

“…Similarly, these authors have also described two DOX-loaded ZIFs (ZIF-7 and ZIF-8) for the liposome-responsive release of DOX. [83] The loading capacity of DOX into ZIF-7 and ZIF-8 was approximately 40% and 52%, respectively, the difference being due to ZIF-7 having a bigger cavity size than ZIF-8. This study showed that both ZIFs were excellent for DOX release when in contact with liposomes.…”

Metal‐Organic Framework as a Protective Coating for Biodiagnostic Chips

“…[27] However, it is not stable in acidic environments because of the loss of the coordination between the zinc ions and imidazolate at pH 5.0–6.0. [28] Therefore, as long as ZIF-8 protected surfaces are stored in dry or nonacidic conditions, the ZIF-8 shell should be stable. For the same reason, water at pH 6 was employed to completely remove the ZIF-8 protective layer and restore the biofunctionality of antibodies conjugated to nanotransducers.…”

Synergistic Antimicrobial Activity in Ampicillin Loaded Core‐Shell ZnO@ZIF‐8 Particles

“…Comparison to a mere physical mixture of the two components i. e., ZnO@ZIF‐8 and antibiotic, the present approach has integrated some key advantages. For instance, the crystalline nature of the ZIF‐8 shell will allow the controlled release of the antibiotic molecules . Additionally, the structural susceptibility of ZIF‐8 shell towards the acidic environment will ensure a pH‐responsive release mechanism of antibiotics which becomes particularly relevant for wound healing applications where the pH of the environment has a direct implication in the healing process .…”