Elucidating the Drug Release from Metal-Organic Framework Nanocomposites via In Situ Synchrotron Microspectroscopy and Theoretical Modeling.

Nanocomposites comprising metal-organic frameworks (MOFs) embedded in a polymeric matrix are promising carriers for drug delivery applications. While understanding the chemical and physical transformations of MOFs during the release of confined drug molecules is challenging, this is central to devising better ways for controlled release of therapeutic agents. Herein, we demonstrate the efficacy of synchrotron microspectroscopy to track the in situ release of 5-fluorouracil (5-FU) anticancer drug molecules from a drug@MOF/polymer composite (5-FU@HKUST-1/polyurethane). Using experimental time-resolved infrared spectra jointly with newly developed density functional theory calculations, we reveal the detailed dynamics of vibrational motions underpinning the dissociation of 5-FU bound to the framework of HKUST-1 upon water exposure. We discover that HKUST-1 creates hydrophilic channels within the hydrophobic polyurethane matrix hence helping to tune drug release rate. The synergy between a hydrophilic MOF with a hydrophobic polymer can be harnessed to engineer a tunable nanocomposite that alleviates the unwanted burst effect commonly encountered in drug delivery.

Effect of essential oil from Ageratum fastigiatum on beta-integrin (CD18) expression on human lymphocytes stimulated with phorbol myristate acetate in vitro.

Agareratum fastigiatum is a Brazilian medicinal plant used as anti-inflammaroty and for wound healing by the folk medicine. In vitro and in vivo studies involving A. fastigiatum essential oil (EOAF) showed indications of anti-inflammatory activity, however, its effect on membrane integrins involved on cell migration is still unclear. Hence, it was evaluated in the present study the effect of EOAF on CD18 frequency on human lymphocytes. By using gas chromatography/mass spectrometry it was identified 9 compounds on EOAF: α-pinene; ß-pinene; ß-myrcene; d-limonene; ß-ocimene; sesquiterpenes; α-copaene; 4,8-ß-epóxi-caryophyllene; germacrene and bicyclogermacrene. On in vitro tests, 6.25 × 10-3 and 12.5 × 10-3 µL/mL EOAF reduced CD18 frequency on phorbol-12-myristate-13-acetate (PMA)-stimulated lymphocytes. Such cells were obtained from peripheral blood of healthy volunteers, and were treated or not with EOAF. They were stained with fluorescent anti-CD18 monoclonal antibodies, after 24 hours incubation. Our data corroborates previous findings, indicating a possible anti-inflammatory activity of EOAF.

Guest-host interactions of nanoconfined anti-cancer drug in metal-organic framework exposed by terahertz dynamics.

A facile mechanochemical method was employed to accomplish one-pot encapsulation of anti-cancer drug 5-fluorouracil (5-FU as guest) in a metal-organic framework (HKUST-1 as host). Vibrational spectroscopy via inelastic neutron scattering was applied to probe guest-host interactions arising from nanoscale confinement. We compare 5-FU@HKUST-1 derived from in situ and ex situ encapsulation.