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A "green" strategy to construct non-covalent, stable and bioactive coatings on porous MOF nanoparticles.

Agostoni V, Horcajada P, Noiray M, Malanga M, Aykaç A, Jicsinszky L, Vargas-Berenguel A, Semiramoth N, Daoud-Mahammed S, Nicolas V, Martineau C, Taulelle F, Vigneron J, Etcheberry A, Serre C, Gref R - Sci Rep (2015)

Bottom Line: Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings.The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities.The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system.

View Article: PubMed Central - PubMed

Affiliation: Institut Galien, Université Paris-Sud, UMR CNRS 8612, 92290 Chatenay Malabry, France.

ABSTRACT
Nanoparticles made of metal-organic frameworks (nanoMOFs) attract a growing interest in gas storage, separation, catalysis, sensing and more recently, biomedicine. Achieving stable, versatile coatings on highly porous nanoMOFs without altering their ability to adsorb molecules of interest represents today a major challenge. Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings. Cyclodextrin molecules bearing strong iron complexing groups (phosphates) were firmly anchored to the nanoMOFs' surface, within only a few minutes, simply by incubation with aqueous nanoMOF suspensions. The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities. The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system. These results pave the way towards the design of surface-engineered nanoMOFs of interest for applications in the field of targeted drug delivery, catalysis, separation and sensing.

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Physico-chemical characterization of the nanoMOFs supramolecular structure and porous surface after modification with CD-P.(a) TEM images of uncoated (upper panel) and coated nanoMOFs (bottom panel) show that the nanoparticles keep the same facetted-type morphology before and after incubation with CD-P aqueous solutions. (b) XRPD patterns of nanoMOFs before (black) and after impregnation with CD-P (red) show that the nanoparticles crystalline structure is not affected by the modification procedure. XRPD patterns correspond to crystalline MIL-10037 (c) Nitrogen physisorption isotherms of nanoMOFs (black) and CD-P-modified nanoMOFs (red) were measured by nitrogen absorption at −196°C. The two curves are almost perfectly overlapping, demonstrating that the nanoparticles porous surface is not perturbed after impregnation with CD-P. On the contrary, after incubation with linear PEG chains (green), the nitrogen absorption dramatically decreases, as a consequence of the partial pores occupancy by the polymer chains.
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f3: Physico-chemical characterization of the nanoMOFs supramolecular structure and porous surface after modification with CD-P.(a) TEM images of uncoated (upper panel) and coated nanoMOFs (bottom panel) show that the nanoparticles keep the same facetted-type morphology before and after incubation with CD-P aqueous solutions. (b) XRPD patterns of nanoMOFs before (black) and after impregnation with CD-P (red) show that the nanoparticles crystalline structure is not affected by the modification procedure. XRPD patterns correspond to crystalline MIL-10037 (c) Nitrogen physisorption isotherms of nanoMOFs (black) and CD-P-modified nanoMOFs (red) were measured by nitrogen absorption at −196°C. The two curves are almost perfectly overlapping, demonstrating that the nanoparticles porous surface is not perturbed after impregnation with CD-P. On the contrary, after incubation with linear PEG chains (green), the nitrogen absorption dramatically decreases, as a consequence of the partial pores occupancy by the polymer chains.

Mentions: Noteworthy, the CD-P coating on nanoMOFs was stable in aqueous solution, as three extensive washings of the nanoMOFs did not lead to any CD-P leaching (SI, Tab S1). Similarly, three washings with phosphate buffer saline (PBS) lead to only 7% CD-P detachment. In addition, despite the high CD-P content, the surface area of the nanoMOFs was maintained at 1350 ± 100 m2.g−1 (Langmuir) before and after CD-P association (Fig. 3c). In contrast, although similar coating amounts (17 wt%) were achieved when nanoMOFs were incubated with poly(ethylene glycol) (PEG) aqueous solutions instead of CD-P ones13, the surface area dramatically decreased to 350 m2.g−1, in agreement with a partial filling and/or blocking of the pores by PEG chains. Presumably, PEG chains can penetrate into the pores by reptation (Fig. 1d), their section (~3.1 Å2) being smaller compared to the size of the windows4142. These studies clearly demonstrate the interest to use coating species with larger rigid sections larger than the windows of the nanoMOFs to avoid pore filling.


A "green" strategy to construct non-covalent, stable and bioactive coatings on porous MOF nanoparticles.

Agostoni V, Horcajada P, Noiray M, Malanga M, Aykaç A, Jicsinszky L, Vargas-Berenguel A, Semiramoth N, Daoud-Mahammed S, Nicolas V, Martineau C, Taulelle F, Vigneron J, Etcheberry A, Serre C, Gref R - Sci Rep (2015)

Physico-chemical characterization of the nanoMOFs supramolecular structure and porous surface after modification with CD-P.(a) TEM images of uncoated (upper panel) and coated nanoMOFs (bottom panel) show that the nanoparticles keep the same facetted-type morphology before and after incubation with CD-P aqueous solutions. (b) XRPD patterns of nanoMOFs before (black) and after impregnation with CD-P (red) show that the nanoparticles crystalline structure is not affected by the modification procedure. XRPD patterns correspond to crystalline MIL-10037 (c) Nitrogen physisorption isotherms of nanoMOFs (black) and CD-P-modified nanoMOFs (red) were measured by nitrogen absorption at −196°C. The two curves are almost perfectly overlapping, demonstrating that the nanoparticles porous surface is not perturbed after impregnation with CD-P. On the contrary, after incubation with linear PEG chains (green), the nitrogen absorption dramatically decreases, as a consequence of the partial pores occupancy by the polymer chains.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4300503&req=5

f3: Physico-chemical characterization of the nanoMOFs supramolecular structure and porous surface after modification with CD-P.(a) TEM images of uncoated (upper panel) and coated nanoMOFs (bottom panel) show that the nanoparticles keep the same facetted-type morphology before and after incubation with CD-P aqueous solutions. (b) XRPD patterns of nanoMOFs before (black) and after impregnation with CD-P (red) show that the nanoparticles crystalline structure is not affected by the modification procedure. XRPD patterns correspond to crystalline MIL-10037 (c) Nitrogen physisorption isotherms of nanoMOFs (black) and CD-P-modified nanoMOFs (red) were measured by nitrogen absorption at −196°C. The two curves are almost perfectly overlapping, demonstrating that the nanoparticles porous surface is not perturbed after impregnation with CD-P. On the contrary, after incubation with linear PEG chains (green), the nitrogen absorption dramatically decreases, as a consequence of the partial pores occupancy by the polymer chains.
Mentions: Noteworthy, the CD-P coating on nanoMOFs was stable in aqueous solution, as three extensive washings of the nanoMOFs did not lead to any CD-P leaching (SI, Tab S1). Similarly, three washings with phosphate buffer saline (PBS) lead to only 7% CD-P detachment. In addition, despite the high CD-P content, the surface area of the nanoMOFs was maintained at 1350 ± 100 m2.g−1 (Langmuir) before and after CD-P association (Fig. 3c). In contrast, although similar coating amounts (17 wt%) were achieved when nanoMOFs were incubated with poly(ethylene glycol) (PEG) aqueous solutions instead of CD-P ones13, the surface area dramatically decreased to 350 m2.g−1, in agreement with a partial filling and/or blocking of the pores by PEG chains. Presumably, PEG chains can penetrate into the pores by reptation (Fig. 1d), their section (~3.1 Å2) being smaller compared to the size of the windows4142. These studies clearly demonstrate the interest to use coating species with larger rigid sections larger than the windows of the nanoMOFs to avoid pore filling.

Bottom Line: Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings.The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities.The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system.

View Article: PubMed Central - PubMed

Affiliation: Institut Galien, Université Paris-Sud, UMR CNRS 8612, 92290 Chatenay Malabry, France.

ABSTRACT
Nanoparticles made of metal-organic frameworks (nanoMOFs) attract a growing interest in gas storage, separation, catalysis, sensing and more recently, biomedicine. Achieving stable, versatile coatings on highly porous nanoMOFs without altering their ability to adsorb molecules of interest represents today a major challenge. Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings. Cyclodextrin molecules bearing strong iron complexing groups (phosphates) were firmly anchored to the nanoMOFs' surface, within only a few minutes, simply by incubation with aqueous nanoMOF suspensions. The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities. The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system. These results pave the way towards the design of surface-engineered nanoMOFs of interest for applications in the field of targeted drug delivery, catalysis, separation and sensing.

Show MeSH
Related in: MedlinePlus