Applications of Metal-Organic Frameworks as Drug Delivery Systems

Abstract

In the last decade, metal organic frameworks (MOFs) have shown great prospective as new drug delivery systems (DDSs) due to their unique properties: these materials exhibit fascinating architectures, surfaces, composition, and a rich chemistry of these compounds. The DSSs allow the release of the active pharmaceutical ingredient to accomplish a desired therapeutic response. Over the past few decades, there has been exponential growth of many new classes of coordination polymers, and MOFs have gained popularity over other identified systems due to their higher biocompatibility and versatile loading capabilities. This review presents and assesses the most recent research, findings, and challenges associated with the use of MOFs as DDSs. Among the most commonly used MOFs for investigated-purpose MOFs, coordination polymers and metal complexes based on synthetic and natural polymers, are well known. Specific attention is given to the stimuli- and multistimuli-responsive MOFs-based DDSs. Of great interest in the COVID-19 pandemic is the use of MOFs for combination therapy and multimodal systems.

Keywords: drug delivery systems; encapsulation; metal organic frameworks; stimulus; surface modification.

Figure 1

MOFs synthesis—alternative reaction conditions. Features shown in blue are advantages and black are disadvantages for all described methods.

Figure 2

Number of publications from Web of Science: (A) “Metal Organic Frameworks” and (B) “Metal Organic Frameworks and Drug Delivery Systems”, from 1996 and 2009, through 21 March 2022.

Figure 3

Some examples of drugs delivered by MOFs as DDS: (a)—indocianine green, (b)—doxorubicin hydrochloride, (c)—5-fluorouracil, (d)—caffeine, (e)—cidofovir, (f)—acid folic, (g)—calcein, (h)—curcumin.

Figure 4

Encapsulation, direct assembly, and post-synthesis of cargo-loading strategies for MOFs. Reproduced with permission from [51]; Copyright (Wang, 2018), RSC J. Mater. Chem. B.

Figure 5

Synthesis of O₂@UiO-66@ICG@RBC (A). Schematic mechanism of NIR-triggered O₂ enhanced and discharging PDT (B). Reproduced with permission from [81]; Copyright (Gao, 2018), Elsevier Biomaterials.

Figure 6

Schematic illustration of metal–organic frameworks (MOFs)-based stimuli-responsive system for drug delivery. Reproduced from reference [110]; Copyright (Cai, 2018) Wiley Online Library.