Optimized synthesis and crystalline stability of γ-cyclodextrin metal-organic frameworks for drug adsorption
Graphical abstract
Introduction
Metal-organic frameworks (MOFs), also known as porous coordination polymers, have emerged as a new class of porous materials for diverse applications such as molecular recognition (Jiecheng et al., 2014, Kumar et al., 2014, Liao et al., 2014), gas storage (Ghose et al., 2015, Kumar et al., 2015, Wen et al., 2012), separation science (Kılıç et al., 2015, Li et al., 2014, Manju et al., 2014), catalysis (Li et al., 2012, Song and Lin, 2012) and drug delivery (Miller et al., 2010, Yun et al., 2013). Usually, they are highly tunable hybrid materials crafted from metal connecting points and organic bridging ligands (Li et al., 1999) with predictable extended structures.
Since the biocompatibility of materials is essential for most potential biological applications, the metals and organic bridging ligands of MOFs have to be bio-friendly. Estimated from the toxicity parameter LD50, some metals such as Ca, Fe, Zn, K, and Ti are considered to be biologically acceptable (Horcajada et al., 2012) and therefore more attention has been paid to biomolecules as linkers of biological active MOFs for biological applications. In addition, natural linkers such as amino acids (Yang et al., 2015), nucleobases (Thomas-Gipson et al., 2015), peptides (Ikezoe et al., 2012), glutarates (Jhung et al., 2006), carbohydrates (Chen et al., 2014), oxalates (Chih-Min and Kwang-Hwa, 2009) and succinates (Cheng et al., 2010) have been reported as being suitable to bind metal ions to form functional porous MOFs.
Recently, the environmental friendly and renewable cyclodextrin (CD) metal-organic frameworks (CD-MOFs) obtained from γ-CD and potassium ions employing a vapor diffusion method have been reported (Forgan et al., 2012, Furukawa et al., 2012, Gassensmith et al., 2011, Smaldone et al., 2010). The γ-CD-MOFs are body-centered cubic structures with apertures of 7.8 Å and have large spherical voids with diameters of 17 Å, linked by coordination of the –OCCO– units located on the D-glucopyranosyl residues of γ-CD to the potassium cations. The extended frameworks of CD-MOFs are connected by numerous channels with a calculated pore volume of 54% (Smaldone et al., 2010). Among the various MOFs reported to date, γ-CD-MOFs are potential materials for gas adsorption (N2, H2, CO2 and CH4) and the sequestering of some small molecules (Rhodamine B by co-crystallization and 4-phenylazophenol by adsorption) within their pores (Smaldone et al., 2010). Taking advantage of the cavities of diameter 1.7 nm and the high local concentrations of the OH− ions, a γ-CD-MOF-based template strategy has been developed (Wei et al., 2012) for the synthesis of silver and gold nanoparticles. The γ-CD-MOFs have also been employed to address the challenging separation and purification requirements of petrochemical feedstocks on account of the fact that their three dimensional transverse channels exhibit superior separation features and high resolutions in comparison with other extended framework materials (Holcroft et al., 2015).
On account of the weak noncovalent bonding interactions between the building blocks and metal centers, the parameters employed in the synthesis, including solvent, metal source, molar ratio of reactants, temperature and duration, have a major influence on the physiochemical properties of CD-MOFs. The preparation of pure, homogeneous and monodisperse crystals is critically important in relation to the potential applications of MOFs. Among the studies devoted to the preparation and application of CD-MOFs (Joong et al., 2011, Khan and Kang, 2011, Stock and Biswas, 2012), the crystalline stability of the materials also showed their effectiveness in the generation of families of porous materials. Very few systematic studies, however, have focused on the chemical, thermal and hydrothermal stabilities of MOFs or γ-CD-MOFs (Cychosz and Matzger, 2010).
In this investigation, γ-CD-MOF crystals were obtained by an optimized vapor diffusion method within a short production time, and the characterization, stability and drug adsorption performance were investigated. The γ-CD-MOF crystals prepared under conditions with different reactant concentrations, temperatures, time, molar ratios of γ-CD to KOH, solvents and surfactants were optimized with reference to their shape and size. The crystalline stability of the γ-CD-MOF crystals produced under different processing conditions was probed primarily using PXRD and SEM. Furthermore, preliminary studies were carried out on the adsorption of 21 drugs to γ-CD-MOFs as well as their adsorption behavior.
Section snippets
Materials and reagents
γ-cyclodextrin was obtained from Maxdragon Biochem Ltd (China). Potassium hydroxide (KOH), cetyl trimethyl ammonium bromide (CTAB), methanol (MeOH), absolute ethanol (EtOH), isopropanol (iPrOH), acetone (Me2CO), dichloromethane (DCM) and N,N-dimethylformamide (DMF) were of analytical grade and purchased from Sinopharm Chemical Reagent Co. Ltd (China). All drugs (>99.5% purity) were purchased from Dalian Meilun Biotech Co., Ltd (China). Pure H2O (18.4 MΩ cm), used in all experiments was purified
Optimized synthesis of micron sized γ-CD-MOFs
A vapor diffusion method has been reported (Smaldone et al., 2010) for the synthesis of γ-CD-MOFs, prepared by dissolving γ-CD (1.30 g, 1 mmol) along with KOH (0.45 g, 8 mmol) in aqueous solution (20 mL), followed by vapor diffusion with MeOH at ambient temperature over the period of a week to produce γ-CD-MOFs as cubic crystals of 40–500 μm in size. A modified method with the addition of CTAB and a controlled incubation time about 26–32 h has been reported (Furukawa et al., 2012) to produce the
Conclusions
In this investigation, a fast solvent evaporation approach was developed to synthesize and tailor the γ-CD-MOFs to a controlled size, with the synthesis period shortened from that reported in the literature of over 26 to 6 h. The size of γ-CD-MOF crystals was adjusted by altering the reactant concentrations, reaction temperatures, reaction time, ratios of γ-CD to KOH and surfactant concentrations, without any marked changes in particle crystallinity and porosity. And the γ-CD-MOF crystals of
Acknowledgements
We are grateful for the financial support from National Science and Technology Major Project (2013ZX09402103) and National Natural Science Foundation of China (81373358). This research is also part of the Joint Center of Excellence in Integrated Nano-Systems (JCIN) at King Abdulaziz City for Science and Technology (KACST) and Northwestern University (NU). The authors would like to thank both KACST and NU for their continued support of this research.
References (46)
- et al.
Three-dimensional hybrid organic-inorganic frameworks based on lanthanide(III) sulfate layers and organic pillars of 1,4-piperazinediacetic acid
J. Mol. Struct.
(2010) - et al.
Adsorption of C.I Basic Blue 9 on cyclodextrin-based material containing carboxylic groups
Dyes Pigm.
(2006) - et al.
Manufacture of dense coatings of Cu-3(BTC)(2) (HKUST-1) on alpha-alumina
Microporous Mesoporous Mater.
(2008) - et al.
Crystal size control of transition metal ion-incorporated aluminophosphate molecular sieves: effect of ramping rate in the syntheses
Microporous Mesoporous Mater.
(2008) - et al.
Sod – ZMOF/Matrimid ®; mixed matrix membranes for CO2 separation
J. Membr. Sci.
(2015) - et al.
Facile synthesis of nano-sized metal-organic frameworks, chromium-benzenedicarboxylate, MIL101
Chem. Eng. J.
(2011) - et al.
Luminescent nanocrystal metal organic framework based biosensor for molecular recognition
Inorg. Chem. Commun.
(2014) - et al.
Methods for the synthesis of large crystals of silicate zeolites
Microporous Mesoporous Mater.
(2005) - et al.
Rapid controllable synthesis of Al-MIL-96 and its adsorption of nitrogenous VOCs
Catal. Today
(2015) - et al.
Controlled release of Captopril by regulating the pore size and morphology of ordered mesoporous silica
Microporous Mesoporous Mater.
(2006)
MOFs meet monoliths: hierarchical structuring metal organic framework catalysts
Appl. Catal. A Gen.
Ammonia removal in anaerobic digestion by biogas stripping: an evaluation of process alternatives using a first order rate model based on experimental findings
Chem. Eng. J.
Control of crystal size and distribution of zeolite A
Ind. Eng. Chem. Res.
Conversion of fructose into 5-hydroxymethylfurfural catalyzed by recyclable sulfonic acid-functionalized metal–organic frameworks
Green Chem.
Synthesis of novel organic-inorganic hybrid compounds: lanthanide phosphites incorporating a squarate ligand
Inorg. Chem.
Water stability of microporous coordination polymers and the adsorption of pharmaceuticals from water
Langmuir ACS J. Surf. Colloids
Controlled multiscale synthesis of porous coordination polymer in nano/micro regimes
Chem. Mater.
Nanoporous carbohydrate metal-organic frameworks
J. Am. Chem. Soc.
Nano- and microsized cubic gel particles from cyclodextrin metal–organic frameworks
Angew. Chem. Int. Ed.
Strong and reversible binding of carbon dioxide in a green metal-organic framework
J. Am. Chem. Soc.
Understanding the adsorption mechanism of Xe and Kr in a metal–organic framework from X-ray structural analysis and first-principles calculations
J. Phys. Chem. Lett.
Carbohydrate-mediated purification of petrochemicals
J. Am. Chem. Soc.
Metal-organic frameworks in biomedicine
Chem. Rev.
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These authors contributed equally to the manuscript.