Tissue poses some diffusion barrier as a function of molecular weight and size; in our preparation the 37 amino acid large CGRP molecule can be expected to diffuse slower than the solutions containing the pharmacological substances.
This was particularly intriguing for the DBD5-GFP construct, since it lacks import signals [20], [22] and is structured as a dimer [5] whose predicted molecular weight as a GFP fusion is 118 kDa, so it would not be expected to diffuse through the nuclear pore.
NAD+, however, is a bulky and highly charged molecule that would not be expected to diffuse across the cytosolic membrane.
Hoechst 33342 binds to cells lining the track of the needle, but tirapazamine was expected to diffuse to hypoxic regions within the tumours.
F-500 would be expected to diffuse a far smaller distance than TR-3 which, in our hands, was not the case.
Given that CpdA is quite lipophilic, it is expected to diffuse rather than be transported across the plasma membrane, so that uptake-related resistance is not possible, in contrast to actively accumulated trypanocidal drug classes like the diamidines (51).
The macro-initiator 3 was expected to diffuse very little due to its large size and binding to the substrate via electrostatic interactions (rather than via a reactive chlorosilane which, in addition, may hydrolyse during the stamping process).
Correlating the sites of dye location and sites of direct photodamage seems allowable since photochemically produced singlet oxygen is expected to diffuse intracellularly to distances limited by its short lifetime to 10 20 nm (Moan and Berg, 1991).
Quercetin is a small and slightly lipophilic molecule (molecular weight=302 Da, octanol water partition coefficient, Ko/w∼1.2±0.13 (Brown et al, 1998)) and is expected to diffuse across cell membranes at a high rate.
