Positive pressure infusion of fluorescent nanoparticles as a probe of the structure of brain phantom gelatins

Positive pressure infusion of Y 2 O 3 :Eu 3+ particles 8-12 nm in size was carried out in 75 cm 3 samples of 0.6% agarose gels that have internal mass transport properties similar to those of in vivo mammalian brain tissue. The purpose of the study was to investigate the nature of the porous-like structure of the gels at distance scales of the order of ≈10 nm. Fluorescence of the particles under UV excitation was used to observe their time-dependent distribution pattern, with the result that the convection-enhanced flow provided by the infusion process caused the particles to permeate the gel's interstitial structure, thus revealing a porosity scale size commensurate with that of the particle size.