New insights on the supramolecular structure of highly porous core–shell drug nanocarriers using solid-state NMR spectroscopy

Abstract

Nano-sized metal–organic frameworks (nanoMOFs), with engineered surfaces to enhance the targeting of the drug delivery, have proven efficient as drug nanocarriers.

Doxorubicin-Loaded Metal-Organic Frameworks Nanoparticles with Engineered Cyclodextrin Coatings: Insights on Drug Location by Solid State NMR Spectroscopy

“…Since both the 13 COO-CD ester and the free 13 COOH had similar chemical shift in the pure polymer, one can infer that the new peak observed in the CD-CO@nanoMIL-100(Al) arises from a strong interaction (maybe a chemical bond) between the citrate and the Al sites located at the surface of the nanoMOF. Such a strong interaction was already observed in the case of CD-P coating [ 17 ]. Note the absence of the COOH proton signal in the 1 H MAS NMR spectrum, which further support the formation of a bond between the free COOH of the CD-CO and the Al atoms located at the surface of the nanoMOF.…”

“…1 H MAS NMR spectra were also recorded ( Figure 6 B). However, as was already observed for MIL-100(Al) nanoMOFs coated with CD-P [ 17 ], due to the presence of numerous protons both in the MOF and in the coating, no useful information could be extracted. In CD-P coated MIL-100(Al) NPs, this difficulty could be circumvented by using the heteroatoms present either in the MOF only (i.e., 27 Al) or in the coating only ( 31 P).…”

“…Aluminum trimesate MIL-100 (Al) nanoMOFs were synthesized as previously described [ 17 , 22 ]. Briefly, 20 mL of an aqueous mixture containing aluminum nitrate nonahydrate (1.43 g) and trimethyl trimesate (1.21 g) was mixed with nitric acid (4 mL, 4 m) at room temperature and then heated at 210 °C for 30 min under stirring by microwave.…”

“…However, a large number of spinning side bands were observed due to the presence of the Fe paramagnetic center, limiting the amount of information that could be extracted from the NMR spectra. More recently, studies were carried out using the diamagnetic MIL-100 (Al) coated and loaded with phosphorus-containing species [ 17 ]. High-resolution 31 P- 27 Al two-dimensional (2D) NMR experiments clearly evidenced the interactions between the nanoMOF external surfaces and the phosphorus-containing coating molecules at the molecular level.…”

“…High-resolution 31 P- 27 Al two-dimensional (2D) NMR experiments clearly evidenced the interactions between the nanoMOF external surfaces and the phosphorus-containing coating molecules at the molecular level. Moreover, useful information has been obtained on the interactions between the nanoMOFs and the drugs located inside their micropores [ 17 ].…”