Synthesis and potential applications of cyclodextrin-based metal–organic frameworks: a review

Abstract

Metal–organic frameworks are porous polymeric materials formed by linking metal ions with organic bridging ligands. Metal–organic frameworks are used as sensors, catalysts for organic transformations, biomass conversion, photovoltaics, electrochemical applications, gas storage and separation, and photocatalysis. Nonetheless, many actual metal–organic frameworks present limitations such as toxicity of preparation reagents and components, which make frameworks unusable for food and pharmaceutical applications. Here, we review the structure, synthesis and properties of cyclodextrin-based metal–organic frameworks that could be used in bioapplications. Synthetic methods include vapor diffusion, microwave-assisted, hydro/solvothermal, and ultrasound techniques. The vapor diffusion method can produce cyclodextrin-based metal–organic framework crystals with particle sizes ranging from 200 nm to 400 μm. Applications comprise food packaging, drug delivery, sensors, adsorbents, gas separation, and membranes. Cyclodextrin-based metal–organic frameworks showed loading efficacy of the bioactive compounds ranging from 3.29 to 97.80%.

Novel γ-cyclodextrin-based metal–organic frameworks for the effective encapsulation of oregano essential oil and controlled release

“…21 Therefore, considering the advantages of g-CD-MOFs, such as being non-toxic, edible, renewable, biodegradable, and high specific surface area, among others, they can be a novel class of porous extension frameworks. 18 Studies have indicated that g-CD-MOFs are excellent carriers for bioactive substances, 20,22,23 including curcumin, 19 menthol, 24 glycyrrhizin acid, 25 vitamin A palmitate, 26 catechin 27 and as a drug carrier. 28 However, although various methods have been used to encapsulate OEO, no studies have been reported about OEO encapsulated in g-CD-MOFs.…”

Microreactor-based micro/nanomaterials: fabrication, advances, and outlook

“…MOFs are a class of multifunctional composite porous crystalline materials in which organic ligands and inorganic metal centers are connected by self-assembly, which can be used as gas storage and separation, catalysts for organic transformations, biomedicine, sensors, photovoltaics and energy conversion. [246][247][248] However, conventional MOFs are synthesized by time-consuming hydrothermal or solvothermal methods, which generally require hours or days for the crystallization and formation of porous networks. Droplet-based microfluidic devices have a high surface-tovolume ratio, efficient mixing and heat transfer efficiency and can eliminate channel blockage and significantly increase the reaction rate; thus, they are widely used in high-throughput biological and biochemical screening experiments.…”

Application of Metal‐Organic Frameworks in Imaging‐Guided Therapy

“…[40,84,89] Cyclodextrins (CDs) are considered the most significant organic ligands among various saccharides due to their intrinsic hydrophobic inner cavity, hydrophilic outer surface, and molecular recognition properties. [90][91][92][93][94][95][96][97][98][99][100][101] The first case of cyclodextrin-based MOF was reported in 2010 by Wang et al [102] , who used K + or Rb + ions were coordinated with six γ-CD units to synthesize a porous γ-CD based MOFs. The incorporation of chitosan's intrinsic hydrophobic inner cavity properties into MOFs in this study has successfully enhanced the potential applications of MOFs in drug loading, controlled drug release, and sewage purification.…”

“…Therefore, they also can serve as organic ligands for the synthesis of MOFs [40,84,89] . Cyclodextrins (CDs) are considered the most significant organic ligands among various saccharides due to their intrinsic hydrophobic inner cavity, hydrophilic outer surface, and molecular recognition properties [90–101] …”