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Asymmetric flow field-flow fractionation (AF4) coupled with UV-Vis spectroscopy, multi-angle light scattering (MALS) and refractive index (RI) detection has been applied for the characterization of MIL-100(Fe) nanoMOFs (metal–organic frameworks) loaded with nucleoside reverse transcriptase inhibitor (NRTI) drugs for the first time. Empty nanoMOFs and nanoMOFs loaded with azidothymidine derivatives with three different degrees of phosphorylation were examined: azidothymidine (AZT, native drug), azidothymidine monophosphate (AZT-MP), and azidothymidine triphosphate (AZT-TP). The particle size distribution and the stability of the nanoparticles when interacting with drugs have been determined in a time frame of 24 h. Main achievements include detection of aggregate formation in an early stage and monitoring nanoMOF morphological changes as indicators of their interaction with guest molecules. AF4-MALS proved to be a useful methodology to analyze nanoparticles engineered for drug delivery applications and gave fundamental data on their size distribution and stability. [Figure not available: see fulltext.].

Metal–organic frameworks (MOFs) are coordination polymers of interest for biomedical applications. Of particular importance, nanoparticles made of iron(III) trimesate (MIL-100, MIL standing for Material Institut Lavoisier) (nanoMOFs) can be conveniently synthesised under mild and green conditions. They were shown to be biodegradable, biocompatible and efficient to encapsulate a variety of active molecules. We have addressed here the challenges to encapsulate a highly hydrophilic anticancer prodrug, phosphated gemcitabin (Gem-MP) known for its instability and inability to bypass cell membranes. MIL-100 nanoMOFs acted as efficient “nanosponges”, soaking Gem-MP from its aqueous solution with almost perfect efficiency (>98%). Maximal loadings reached ∼30 wt% reflecting the strong interaction between the drug and the iron trimesate matrices. Neither degradation nor loss of crystalline structure was observed after the loading process. Storage of the loaded nanoMOFs in water did not result in drug release over three days. However, Gem-MP was released in media containing phosphates, as a consequence to particle degradation. Drug-loaded nanoMOFs were effective against pancreatic PANC-1 cells, in contrast to free drug and empty nanoMOFs. However, an efflux phenomenon could contribute to reduce the efficacy of the nanocarriers. Size optimization and surface modification of the nanoMOFs are expected to further improve these findings.

Doxorubicin (DOX) entrapment in porous Fe(III)-trimesate metal organic frameworks (MIL-100(Fe)) nanoparticles was investigated in neutral Tris buffer via UV-vis absorption, circular dichroism (CD), and fluorescence. The binding constants and the absolute spectra of the DOX-MIL-100(Fe) complexes were determined via absorption and fluorescence titrations. A binding model where DOX associates as monomer to the dehydrated Fe3O (OH)(H2O)2 [(C6H3)(CO2)3]2 structural unit in 1:1 stoichiometry, with apparent association constant of (1.1 to 1.8) × 10(4) M(-1), was found to reasonably fit the experimental data. Spectroscopic data indicate that DOX binding occurs via the formation of highly stable coordination bonds between one or both deprotonated hydroxyl groups of the aglycone moiety and coordinatively unsaturated Fe(III) centers. Complete quenching of the DOX fluorescence and remarkable thermal and photochemical stability were observed for DOX incorporated in the MIL-100(Fe) framework.

A comparison of the properties of the highly porous iron(III) trimesate MIL-100 nanoparticles (nano-MOFs) obtained through a hydrofluoric acid-free ‘green’ synthesis route with those obtained from the ‘conventional’ HF procedure is reported, in terms of particle crystallinity, porosity and space time yield (STY). It appears that the use of more concentrated reaction conditions have led to the highest STY values while maintaining a good degree of purity. As the fluorinated nano-MOFs, the F-free solids are able to encapsulate high payloads of a challenging antiviral drug, azidothymidine triphosphate, and to release it on a progressive manner. Furthermore, the F-free nano-MOFs were shown to be highly taken up by macrophages, targets for antiviral therapy, without inducing any detectable toxic side effects. This study opens up novel perspectives for the large-scale synthesis of ‘green’ MIL-100 nano-MOFs for biomedical applications. Supplementary information will be available at http://www.icevirtuallibrary.com/upload/10.1680gmat.13.00001_SupplementaryInformation.pdf

The association of doxorubicin (DOX) and artemisinin (ART) to a beta-CyD-epichlorohydrin crosslinked polymer (p beta-CyD), organized in nanoparticles of ca. 15 nm size, was investigated in neutral aqueous medium by circular dichroism (CD), UV-vis absorption and fluorescence. The stability constants and the absolute CD spectra of the drug complexes were determined by global analysis of multiwavelength data from spectroscopic titrations. The polymer p beta-CyD proved able to disrupt the DOX dimer when the latter is the predominant form of DOX in solution. The spectroscopic and photophysical properties of the complexes evidenced an alcohol-like environment for ART and an improved inherent emission ability for DOX in the nanoparticle frame.

Background. Cytokine induced killer cells are ex-vivo expanded cells with potent antitumoral activity. Cytokine induced killer cells infusion in acute myeloid leukemia patients relapsing after allogeneic hematopoietic stem cell transplant is well tolerated, but limited clinical responses were observed. To improve their effector functions against acute myeloid leukemia, we genetically modified cytokine induced killer cells with chimeric receptors specific for the CD33 myeloid antigen. Design and Methods. SFG-retroviral vectors coding for anti-CD33-ζ and anti-CD33-CD28-OX40-ζ chimeric receptors were used to transduce cytokine induced killer cells. Transduced cells were in vitro characterized for their ability to lyse leukemic targets (4-hour-51Chromium-release and 6-day co-cultures assays on human stromal mesenchymal cells), to proliferate (3H-thymidine-incorporation assay) and to secrete cytokines (Flow cytomix assay) after contact with acute myeloid leukemia cells. Their activity against normal CD34+ hematopoietic progenitors was evaluated by analyzing the colony forming unit capacity after co-incubation. Results. Cytokine induced killer cells were efficiently transduced with the anti-CD33 chimeric receptors, maintaining their native phenotype and functions and acquiring potent cytotoxicity (up to 80% lysis after 4-hour incubation) against different acute myeloid leukemia targets, as also confirmed in long-term killing experiments. Moreover, introduction of the anti-CD33 chimeric receptors was accompanied by a prominent CD33-specific proliferative activity, with a release of high levels of immunostimulatory cytokines. The presence of CD28-OX40 in chimeric receptor endodomain was associated with a significant amelioration of cytokine induced killer cells anti-leukemic activity. Importantly, even though anti-CD33 chimeric receptors-transduced cytokine induced killer cells showed toxicity against normal hematopoietic CD34+ progenitors, a residual clonogenic activity was preserved. Conclusions. Our results indicate that anti-CD33 chimeric receptors strongly enhance anti-leukemic cytokine induced killer functions, suggesting that cytokine induced killer cells transduced with these molecules might represent a promising optimized tool for acute myeloid leukemia immunotherapy.