Cyclodextrin Metal Organic Frameworks Research Articles

β-Cyclodextrin metal-organic framework as a green carrier to improve the dissolution, bioavailability, and liver protective effect of luteolin

The incidence of acetaminophen-induced liver injury has increased, but effective prevention methods are limited. Although luteolin has hepatoprotective activity, its low solubility and bioavailability limit its applications. Cyclodextrin metal-organic frameworks (CD-MOFs) possess 3D-network structures and large inner cavities, which make them excellent carriers of poorly soluble drugs. In this study, we used CD-MOFs as carriers to improve the dissolution of luteolin and assessed their antioxidant activity, bioavailability, and hepatoprotective effects. Luteolin was loaded into β-CD-MOF, γ-CD-MOF, β-CD, and γ-CD, and characterized by powder X-ray diffractometry (PXRD) and thermogravimetric analysis (TGA). Our results showed that luteolin-β-CD-MOF was the most stable. The main driving forces were hydrogen bonds and van der Waals forces, as determined by molecular simulation. The loading capacity of luteolin-β-CD-MOF was 14.67 wt%. Compared to raw luteolin, luteolin-β-CD-MOF exhibited a 4.50-fold increase in dissolution and increased antioxidant activity in vitro. Luteolin-β-CD-MOF increased the bioavailability of luteolin by approximately 4.04- and 11.07-fold in healthy rats and liver injured rats induced by acetaminophen in vivo, respectively. As determined by biochemical analysis, luteolin-β-CD-MOF exhibited a better hepatoprotective effect than raw luteolin in rats with acetaminophen-induced liver injury. This study provides a new approach for preventing acetaminophen-mediated liver damage.

Purification of gamma-cyclodextrin via selective coordination with potassium ions to form metal-organic frameworks

Efficient purification of gamma-cyclodextrin (γ-CD) is always challenging due to its structural similarity to other CDs and low crystallinity in water. In addressing this issue, an approach was proposed based on the formation mechanism of cyclodextrin metal-organic frameworks (CD-MOFs). This method involved the selective coordination of CDs mixture with potassium ions in water, facilitated by ethanol-induced crystallization, leading to the purification of γ-CD. The results showed that potassium ions enhanced γ-CD crystallization, and ethanol was crucial to selectively coordinating potassium ions with γ-CD. The characterizations revealed that the resulting CD-MOFs exhibited a small particle size, high surface area, and high thermal stability, and was identical to γ-CD-MOF, further indicating the final γ-CD with high purity. The separation factors of γ-CD/α-CD and γ-CD/β-CD were 309 and 260, respectively. Moreover, this method was validated through its application to the industrial enzymatic CDs mixture. The purification of γ-CD could achieve 99.99 ± 0.01 % after four crystallization cycles. Therefore, selectively coordinating with potassium ions to form MOFs provided a valuable reference for the purification of γ-CD and even the direct synthesis of γ-CD-MOF from CDs mixture. This advancement will also benefit the future production and application of γ-CD.

Advancing water treatment: Harnessing cyclodextrin metal-organic frameworks with dual protonation sites for enhanced sulfate adsorption efficiency

TTH-CD-MOF was synthesized for sulfate ion adsorption from aqueous solutions, employing cross-linking modification of γ-CD-MOF with N-hydroxyethyl-morpholine as the modifier and triisocyanate as the cross-linking agent. The adsorbent underwent characterization through Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption-desorption, and other analytical methods. Additionally, the impact of factors such as pH, adsorbent dosage, initial concentration, and ionic strength on adsorption performance was investigated. Adsorption experiments demonstrated the robust efficiency of TTH-CD-MOF for SO42- up to 95.3%, conforming to Langmuir isothermal and pseudo-second-order kinetic models, and higher temperatures favored SO42- adsorption. The maximum adsorption capacity was 189.51 mg·g−1 (25 °C). The adsorption mechanism comprised electrostatic interaction, adsorption within the cavities and pores of γ-CD-MOF. TTH-CD-MOF demonstrates effective sulfate removal from aqueous solutions, establishing its potential as an efficient anion adsorbent.

Design and therapeutic application of trans‐sodium crocetinate‐loaded cyclodextrin metal–organic frameworks as an enteric preparation for treating chronic heart failure

Chronic heart failure (CHF) arises from structural and functional changes in the myocardial tissue attributable to various etiologies. Crocetin and its derivative trans‐sodium crocetinate (TSC) have exhibited cardioprotective attributes; however, their poor aqueous solubility and bioavailability impede clinical development. This study aimed to construct a cyclodextrin metal–organic frameworks (CDMOFs)‐based oral delivery system to enhance the pharmacokinetic profile and therapeutic efficacy of TSC for CHF treatment. TSC was loaded into the synthesized γ‐CDMOFs via vacuum adsorption. The CDMOFs@TSC formulation was characterized and evaluated in vitro. Pharmacokinetic and pharmacodynamic analyses were performed in beagle dogs and CHF rats induced by coronary artery ligation, respectively. Both TSC and CDMOFs@TSC elicited no discernible toxicity or pathological changes in major organs of rats, providing preliminary evidence for their biosafety. Pharmacokinetic study in beagle dogs demonstrated that CDMOFs@TSC capsules markedly increase the relative oral bioavailability by 198% versus free TSC capsules. In rats afflicted with CHF, the administration of CDMOFs@TSC yielded notable enhancements in cardiac function. Additionally, it precipitated a reduction in biomarkers linked to myocardial injury, manifested anti‐inflammatory and antifibrotic effects, and induced alterations in myocardial energy metabolism. This is the first report of CDMOFs‐based oral delivery to improve the TSC bioavailability and efficacy. The utilization of CDMOFs@TSC resulted in superior therapeutic outcomes in comparison to standalone TSC by optimizing pharmacokinetics and precise targeted delivery. These results highlight the clinical potential of CDMOF as porous carriers to enable oral delivery of natural products for CHF therapy.

Cyclodextrin Metal-Organic Frameworks as a Drug Delivery System for Selected Active Pharmaceutical Ingredients.

The cyclodextrin-based metal-organic frameworks (CD MOFs) are a suitable molecular platform for drug delivery systems of various active pharmaceutical ingredients (APIs). The low toxicity and cost-efficient synthesis make CD MOFs an attractive host for the encapsulation of APIs. In this study, we created a model system based on γCD-K MOFs with widely used drugs carmofur (HCFU), 5-fluorouracil (5-FU), and salicylic acid (HBA) to study host-guest encapsulation methods using different crystallization protocols. The host-guest complexes of API:CD MOF in an in-depth study were investigated by liquid chromatography-mass spectrometry (LC-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and 19F- and 13C-detected solid-state NMR spectroscopy (ssNMR). These techniques confirmed the structure and interaction sites within the encapsulation product in the host-guest complex. We also evaluated the toxicity and biocompatibility of the API:CD MOF complex using in vitro and in vivo methods. The cytotoxicity, hepatotoxicity, and neurotoxicity were established with cell lines of fibroblasts (BJ), human liver cell line (HepG2), and human oligodendrocytic cells (MO3.13). Then, Danio rerio was used as an in vivo experimental model of ecotoxicity. The results showed the choice of γCD-K-5 as the most protective and safe option for drug encapsulation to decrease its toxicity level against normal cells.

Carboxymethyl potato starch hydrogels encapsulated cyclodextrin metal-organic frameworks for enantioselective loading of S-naproxen and its programmed release

A natural polysaccharide-based vehicle is facilely prepared for enantioselective loading of S-naproxen (S-NPX) and its programmed release. Cyclodextrin metal-organic frameworks (CD-MOF) are synthesized through the coordination of K+ with γ-cyclodextrin (γ-CD). Compared with R-NPX, the CD-MOF preferably combines with S-NPX, which can be confirmed by the thermodynamic calculations. The S-NPX loaded CD-MOF (CD-MOF-S-NPX) is grafted with disulfide bond (–S–S–) to improve its hydrophobicity, and the loaded S-NPX is further encapsulated in the chiral cavity of γ-CD by carboxymethyl potato starch (CPS) hydrogels. The intermolecular hydrogen bonding of the CPS hydrogels is prone to be destroyed in mildly basic media (∼pH 8.0), resulting in the swelling of the hydrogels; the –S–S– linkage in the vehicle can be cleaved in the presence of glutathione (GSH), leading to the collapse of the CD-MOF. Therefore, the programmed release of S-NPX can be achieved. Also in this work, the release kinetics is investigated, and the results indicate that the release of S-NPX is controlled by the Higuchi model.

PAN/PVP/CD-MOF Composite Beads for the Removal of Methylene Blue and Congo Red in Water

Cyclodextrin metal-organic frameworks (CD-MOFs) are synthesized from green precursors, making them an ideal material for green adsorbents. However, CD-MOFs are unstable in water, thus limiting their applications. Here, we report encapsulating CD-MOFs in polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) polymeric support to produce PAN/PVP/CD-MOF composite beads. Batch adsorption studies showed that high dye adsorption capacities could be obtained at intermediate PVP, high PAN, and low CD-MOF loadings. Maximum MB and CR sorption capacities under optimum bead formulation: PAN = 6.96 wt.%, PVP = 2.20 wt.%, and CD-MOF = 2.88 wt.%. The optimized composite beads have a sorption capacity of 37.40 mg/g for MB and 18.42 mg/g for CR. We showed that PAN/PVP/CD-MOF composite beads could be an excellent adsorbent for textile dye removal in water.

Enhanced stability of anthocyanins by cyclodextrin–metal organic frameworks: Encapsulation mechanism and application as protecting agent for grape preservation

Anthocyanins are promising naturally occurring food preservatives for enhancing the quality of food products due to their excellent antioxidant properties. However, their low stability hinders their food packaging application. Here, we propose a facile strategy to achieve the improved stability of anthocyanins encapsulated in γ-cyclodextrin metal-organic frameworks (CD-MOFs) with an in-depth exploration of their structure–property relationships. The adsorbed anthocyanins in CD-MOFs are stabilized by multiple cooperative non-covalent interactions including hydrogen bonding and van der Waals (vdW) interactions as demonstrated by density functional theory (DFT) calculations and spectroscopy analysis. Particularly, by ion-exchange of acetate ions into the pores of CD-MOFs, the resulting CD-MOFs (CD-MOF_OAc) shows a higher anthocyanins adsorption rate with a maximum loading capacity of 83.7 % at 1 min. Besides, CD-MOF_OAc possesses the more effective protecting effect on anthocyanins with at least two-fold enhancement of stability in comparison of free anthocyanins under heating and light irradiation. The anthocyanins encapsulated CD-MOFs films for fruit freshness was validated by the Kyoho experiment. This novel encapsulation system provides a new possibility for the potential use of CD-MOFs as the encapsulating material for anthocyanins in fruit preservation.

Antibacterial, anti-inflammatory, rapid hemostasis, and accelerated repair by multifunctional metal–organic frameworks fibrous scaffolds for diabetic wounds

Excessive inflammation, bacterial infection, persistent bleeding, and wound exudate accumulation are common in diabetic wounds, impeding cell proliferation and disturbing tissue remodeling, making it difficult for diabetic wounds to heal. The rapid hemostasis and reduction of bacterial infection, as well as the excessive infiltration of inflammatory factors, serve as key strategies for diabetic wound healing. In this study, Taxifolin (TAX) was loaded onto cyclodextrin metal–organic frameworks (CD-MOFs), which were subsequently loaded into polycaprolactone (PCL) scaffolds via electrostatic spinning to construct multifunctional electrospun fibrous membranes (EFMs) with antimicrobial, anti-inflammatory, hemostatic, and wound exudate-absorbent properties. The resulting EFMs exhibited a hydrophilic surface, which facilitated wound adhesion and enhanced its hemostatic properties. By aggregating the wound exudate and triggering a cascade release of TAX, bacterial infection in the wound was reduced, decreasing the expression of inflammatory factors. This also promoted collagen deposition, vascular regeneration, and myofibroblast contraction and migration and facilitated the remodeling and repair of the wound tissue. These results demonstrated that designed fibrous scaffolds could effectively accelerate the repair process of diabetic mice, providing a new strategy for the treatment of diabetic wounds.

Chitosan-graft-poly(lactic acid)/CD-MOFs degradable composite microspheres for sustained release of curcumin

The solubility of cyclodextrin metal-organic frameworks (CD-MOFs) in aqueous media making it not suitable as sustained-release drug carrier. Here, curcumin-loaded CD-MOFs (CD-MOFs-Cur) was embedded in chitosan-graft-poly(lactic acid) (CS-LA) via a solid-in-oil-in-oil (s/o/o) emulsifying solvent evaporation method forming the sustained-release composite microspheres. At CS-LA concentration of 20 mg/mL, the composite microspheres showed good sphericity. The average particle size of CS-LA/CD-MOFs-Cur (2:1), CS-LA/CD-MOFs-Cur (4:1) and CS-LA/CD-MOFs-Cur (6:1) composite microspheres was about 9.3, 12.3 and 13.5 μm, respectively. The above composite microspheres exhibited various degradation rates and curcumin release rates. Treating in HCl solution (pH 1.2) for 120 min, the average particle size of above microspheres reduced 28.19 %, 24.34 % and 6.19 %, and curcumin released 86.23 %, 78.37 % and 52.57 %, respectively. Treating in PBS (pH 7.4) for 12 h, the average particle size of above microspheres reduced 30.56 %, 26.56 % and 10.66 %, and curcumin released 68.54 %, 54.32 % and 31.25 %, respectively. Moreover, the composite microspheres had a favorable cytocompatibility, with cell viability of higher than 90 %. These composite microspheres open novel opportunity for sustained drug release of CD-MOFs.

PAN/PVP/CD-MOF composite beads for the removal of Crystal Violet and Brilliant Blue G in water

Cyclodextrin metal–organic frameworks (CD-MOFs) have a high surface area and unique coordination chemistry that enable them to be used as a carrier material for various materials. However, it is unstable in water, limiting its application in aqueous solutions. Here, we report the application of CD-MOFs in treating cationic and anionic dyes in water for the first time by forming a composite with polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) to form composite beads. The composition of the composite beads was optimized through a Box-Behnken design of experiments. The optimum composition of PAN = 5.91 wt%, PVP = 1.89 wt%, and CD-MOF = 2.68 wt% yielded a CV and BB sorption capacities of 50.8109 ± 0.0634 mg/g and 28.5583 ± 0.1296 mg/g, respectively. The composite beads were characterized using SEM, EDX, and FTIR. We showed that CD-MOFs could be used as an adsorbent for wastewater treatment.

Crosslinked γ-cyclodextrin metal organic framework for stable ibuprofen loading

Ibuprofen (IBU) is a commonly used non-steroidal anti-inflammatory drug (NSAIDs), but its solubility is poor in both aqueous and physiological environments . To improve its oral bioavailability and absorption, IBU is loaded into a material, with cyclodextrin metal–organic frameworks (CD-MOFs) being a promising drug carrier. To overcome the instability of CD-MOFs in humid conditions, a cross-linking agent Isophorone diisocyanate (IPDI) was introduced, and a novel cross-linked material CL-CD-MOFs was prepared. On this basis, two IBU-loaded materials, CL-CD-MOFs-IBU, were prepared through different reaction sequences. Research shows that CL-CD-MOFs exhibit stability in water and humid environments, whereas CD-MOFs readily dissolve. Furthermore, this material demonstrates higher IBU loading and encapsulation rates, as well as sustained drug release. Cell toxicity studies indicate that CL-CD-MOFs-IBU exhibit good biocompatibility.

From macro to nano crystals of cyclodextrin metal–organic frameworks and their use as optical functional materials

From macro to nano crystals of cyclodextrin metal–organic frameworks and their use as optical functional materials

Solvent-Free Loading of Vitamin A Palmitate into β-Cyclodextrin Metal-Organic Frameworks for Stability Enhancement.

Cyclodextrin metal-organic frameworks (CD-MOFs) exhibit a high structural diversity, which contributes to their functional properties. In this study, we have successfully synthesized a novel type of β-cyclodextrin metal-organic framework (β-CD-POF(I)) that exhibits excellent drug adsorption capacity and enhances stability. Single-crystal X-ray diffraction analysis revealed that β-CD-POF(I) possessed the dicyclodextrin channel moieties and long-parallel tubular cavities. Compared with the reported β-CD-MOFs, the β-CD-POF(I) has a more promising drug encapsulation capability. Here, the stability of vitamin A palmitate (VAP) was effectively improved by the solvent-free method. Molecular modeling and other characterization techniques like synchrotron radiation Fourier transform infrared spectroscopy (SR-FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), and nitrogen adsorption isotherm were applied to confirm that the VAP was successfully encapsulated into the channel formed by the dicyclodextrin pairs. Furthermore, the mechanism of stability enhancement for VAP was determined to be due to the constraint and separation effects of β-CD pairs on VAP. Therefore, β-CD-POF(I) is capable of trapping and stabilizing certain unstable drug molecules, offering benefits and application possibilities. One kind of cyclodextrin particle with characteristic shapes of dicyclodextrin channel moieties and parallel tubular cavities, which was synthesized by a facile process. Subsequently, the spatial structure and characteristics of the β-CD-POF(I) were primarily confirmed. The structure of β-CD-POF(I) was then compared to that of KOH-β-CD-MOF, and a better material for vitamin A palmitate (VAP) encapsulation was determined. VAP was successfully loaded into the particles by solvent-free method. The arrangement of spatial structure made cyclodextrin molecular cavity encapsulation in β-CD-POF(I) more stable for VAP capture than that of KOH-β-CD-MOF.

Diffusion Kinetics-Based Loading of Lipoic Acid into Cyclodextrin Metal–Organic Frameworks via a Solvent-Free Method and Mechanism of Stability Enhancement

It is difficult to accurately distinguish the amount of a drug inside versus outside of a carrier during drug loading, which limits the ability to determine the kinetic data (the drug diffusion coefficient, energy barrier, etc.). Here, we demonstrated the feasibility of determining the drug diffusion coefficient and content without distinguishing whether it is inside or outside of a carrier. Specifically, the sample of gamma-cyclodextrin metal–organic frameworks (CD-MOF) loaded with unstable and viscous alpha-lipoic acid (LA) was examined. Furthermore, the LA stability was enhanced by the CD-MOF via a straightforward and unambiguous solvent-free method, and the mechanism behind it was thoroughly explored based on the diffusion coefficient. For the first time, a combination of mathematical modeling and new experimental measurements was used to determine the diffusion coefficient of LA in CD-MOF crystals. Accordingly, the strong adhesion free energy (−8.64 ± 0.56 kcal·mol–1) between LA and the dicyclodextrin cavity in the CD-MOF was determined. Furthermore, the nature of the adhesion force was identified to be the chemisorption dominated by hydrogen binding employing a combination of molecular modeling (docking and density functional theory, DFT) and experimental methods (solid-state nuclear magnetic resonance, ssNMR). Finally, this study revealed that the stability enhancement of LA in the CD-MOF is due to the combined actions of the high binding free energy of LA with the dicyclodextrin cavity and its steric hindrance, together with the accelerating roles of the CD-MOF cage environment.

Near-Infrared Light-Mediated Cyclodextrin Metal-Organic Frameworks for Synergistic Antibacterial and Anti-Biofilm Therapies.

Bacterial infections pose a significant threat to global public health; therefore, the development of novel therapeutics is urgently needed. Herein, a controllable antibacterial nanoplatform utilizing cyclodextrin metal-organic frameworks (CD-MOFs) as a template to synthesize ultrafine silver nanoparticles (Ag NPs) in their porous structure is constructed. Subsequently, polydopamine (PDA) is encapsulated on the CD-MOFs' surface via dopamine polymerization to enhance the water stability and enable hyperthermia capacity. The resulting Ag@MOF@PDA generates localized hyperthermia and gradually releases Ag+ to achieve long-term photothermal-chemical bactericidal capability. The release rate of Ag+ can be accelerated by NIR-mediated heating in a controllable manner, quickly reaching the effective concentration and reducing the frequency of medication to avoid potential toxicity. In vitro experiments demonstrate that the combined antibacterial strategy can not only effectively kill both gram-negative and gram-positive bacteria, but also directly eradicate mature biofilms. In vivo results confirm that both bacterial- and biofilm-infected wounds treated with a combination of Ag@MOF@PDA and laser exhibit satisfactory recovery with minimal toxicity, displaying a superior therapeutic effect compared to other groups. Together, the results warrant that the Ag@MOF@PDA realizes synergistic antibacterial capacity and controllable release of Ag+ to combat bacterial and biofilm infections, providing a potential antibiotic-free alternative in the "post-antibiotic era."

Green and edible cyclodextrin metal-organic frameworks modified polyamide thin film nanocomposite nanofiltration membranes for efficient desalination

Nanofiltration membranes are widely used in water treatment applications. However, their performance is often limited due to the trade-off between permeability and selectivity. To overcome this limitation, the incorporation of metal-organic frameworks (MOFs) into polyamide layers to prepare thin film nanocomposite polyamide membranes has been extensively investigated. However, these reported MOFs usually contain toxic heavy metal ions and ligands, posing the risk of leaching during the filtration process and being harmful to environment and even human health. In this work, γ-cyclodextrin and K+ were used to prepare green and edible cyclodextrin MOF (CD-MOF) nanoparticles. Furthermore, these CD-MOF nanoparticles were further loaded at the porous substrate surface to prepare polyamide nanofiltration membranes. The CD-MOF nanoparticles delay the diffusion of PIP molecules and leads to a thin PA layer. In addition, the rough substrate surface loaded with CD-MOF provide an uneven interfacial polymerization reaction interface. After the dissolvement of the CD-MOF nanoparticles, a wrinkled PA structure eventually formed. The PWP of the optimal membrane was 24.4 L m-2 h-1 bar-1, which was 502% higher than that of the controlled TFC membrane, and the Na2SO4 rejection was improved to 97.1%. More ordered surface and negative electrical properties increase the selectivity of divalent to monovalent ions. Compared to conventional TFC nanofiltration membranes, the novel TFN membrane successfully overcame the longstanding permeability and selectivity trade-off. The current work expands the potential of CD-MOF to be utilized in the fabrication of high-performance NF membranes.

High internal phase pickering emulsions stabilized by ODSA-functionalized cyclodextrin metal-organic frameworks for extrusion 3D printing application

Cyclodextrin metal-organic frameworks (CD-MOFs) are novel ordered porous materials with high adsorption and interfacial stabilization. Herein, oil-in-water emulsions stabilized by octadecenylsuccinic anhydride (ODSA) modified CD-MOFs (OCMs) with a volume fraction of 0.8 were prepared. A contact angle of 92° was achieved when 5 wt% ODSA was added to OCMs, which promoted the stabilization of OCMs-emulsions with homogeneous and spherical droplets. Moreover, the emulsion possessed a small droplet size of 7–9 μm (d4,3), long-term storage stability and flocculation resistance. At the pH range of 10–12, the emulsions had a more desirable structure with a gel-like elastic network and a dense particle layer covered onto the droplets, which were verified by SEM and cryo-SEM. The 2D cross-linked particle film at the water-oil interface and the 3D cross-linked gel-like particle network in the continuous phase synergistically improved the stability of coalescence and flocculation of the OCMs-HIPPEs. Afterwards, the OCMs-HIPPEs with no discernible oil were used as printing ink, which had no droplet coalescence in the freeze-thaw and showed high 3D printing quality and shape retention. Overall, this study demonstrates that the ODSA-modified CD-MOFs with favorable properties may be used to fabricate high-quality edible HIPPEs for extrusion 3D printing ink.

Lactone Stabilized by Crosslinked Cyclodextrin Metal-Organic Frameworks to Improve Local Bioavailability of Topotecan in Lung Cancer

The protection of unstable anticancer molecules and their delivery to lesions are challenging issues in cancer treatment. Topotecan (TPT), a classic cytotoxic drug, is widely used for treating refractory lung cancer. However, the therapeutic effects of TPT are jeopardized by its active lactone form that is intrinsically hydrolyzed in physiological fluids, resulting in low bioavailability. Herein, the TPT-loaded crosslinked cyclodextrin metal-organic framework (TPT@CL-MOF) was engineered to improve the local bioavailability of TPT for the treatment of lung cancer. CL-MOF exhibited the efficient loading (12.3 wt%) of TPT with sustained release characteristics. In particular the formulation offered excellent protection in vitro against hydrolysis and increased the half-life of TPT from approximately 0.93 h to 22.05 h, which can be attributed to the host-guest interaction between cyclodextrin and TPT, as confirmed by molecular docking. The TPT@CL-MOF could effectively kill the cancer cells and inhibit the migration and invasion of B16F10 cells in vitro. Moreover, TPT@CL-MOF was efficiently distributed in the lungs after intravenous administration. In an in vivo study using a B16F10 pulmonary metastatic tumor model, TPT@CL-MOF significantly reduced the number and size of metastatic lung nodules at a reduced low dose by five times, and no noticeable side effects were observed. Therefore, this study provides a possible alternative therapy for the treatment of lung cancer with the camptothecin family drugs or other unstable therapeutically significant molecules.

Sustainable γ-cyclodextrin frameworks containing ultra-fine silver nanoparticles with enhanced antimicrobial efficacy

Cyclodextrin metal-organic frameworks (CD-MOF) are a class of biocompatible MOF with a great potential in drug delivery applications. Original CD-MOF crystals are fragile and large (0.2–1 mm), which are less useful in pharmaceutical applications. Cetyltrimethylammonium bromide and long chain poly(ethylene) glycol, used in size modulation to produce nanosized CD-MOF can compromise the biocompatibility, and physiochemical properties of CD-MOF as their complete removal from frameworks is difficult. To avoid the use of above-mentioned modulators, herein, we demonstrate the synthesis of nanosized CD-MOF using triethylamine (TEA) as a modulator to reduce their size to ~254 nm. The MOF characteristics such as crystal and chemical structure remain unaffected and the surface area of CD-MOF synthesised with TEA is measured 1075.5 m2/g, almost 50 % higher than those of synthesised using bulky modulators. The improved CD-MOF architecture utilized for the in-situ synthesis of silver nanoparticles resulted in enhanced antimicrobial efficacy tested against Staphylococcus aureus and Escherichia coli bacteria and Candida albicans fungus. And minimum inhibitory concentration (MIC) is recorded in the range of 31–15 μg/mL. Overall, the structural improvement in CD-MOF supported with thorough comparative investigations and enhanced antimicrobial efficacy could be very helpful in further establishing them in biomedicine field.