Perfluorocarbon-loaded lipid nanocapsules as oxygen sensors for tumor tissue pO2 assessment

Perfluorocarbon-Loaded Lipid Nanocapsules to Assess the Dependence of U87-Human Glioblastoma Tumor pO2 on In Vitro Expansion Conditions

“…In order to assess the tumoral oxygenation, an intratumoral injection of perfluorocarbon-loaded nanocapsules was performed as previously described [16]. The pO 2 value measured at rest, i.e.…”

“…In order to understand the physiological causes of this differential growth, the vascularization of both types of tumor was assessed using non-invasive ASL-MRI and invasive histology. Tumor pO 2 was also measured using specially designed fluorinated nanosensors [16]. …”

“…Perfluoro-15-crown-5-ether (PFCE) loaded lipid nanocapsules (LNCs) (thus PFCE-LNC) were prepared as previously described using a phase-inversion process [16,17]. Briefly, the quantities of the PFCE (oil phase), water and NaCl (aqueous phase), Kolliphor ® HS15 and Lipoïd (surfactants) were precisely weighed: m PFCE = 5 g, m Kolliphor = 2.115 g, m Lipoïd = 0.188 g, m Water = 5 g and m NaCl = 0.5 g. A four step process was performed to obtain PFCE-LNCs: to dissolve the Lipoïd within the initial solution, the temperature was increased from standing room temperature to 95°C, where after a 1 minute sonication, using a Microson XL2007 sonication probe set at 10 W (Misonix, Farmingdale, USA) was performed, prior to three heating and cooling cycles from 25°C to 95°C.…”

“…The geometrical parameters were fixed at FOV = 2 x 2 cm, matrix 64 x 36 zero-filled to 64 x 64, slice thickness = 4 mm, and one average was performed. A Half-Fourier Acquisition Single-Shot Turbo Spin-Echo (HASTE) sequence (RARE factor = 36, TE = 4.6 ms, TR = 6 s) with 16 inversion times ranging between 30 ms to 3500 ms was used to produce T1 maps which were converted into tumoral pO 2 as previously reported [16]. …”

“…With the present study, we are reporting the in vivo characterization of a U87-MG tumor model initially expanded under mild (3%) or atmospheric oxygen (21%) conditions, in terms of blood perfusion and oxygenation. Data were obtained using magnetic resonance (MR) imaging, respectively; arterial spin labelling (ASL) [15] and fluorine oximetry ( 19 F-oximetry) using dedicated oxygen nanosensors [16]. …”