Arginine stereochemistry (D versus L) had little effect on the uptake of CPPÀPMOF conjugates. We compared the MF of R 8 À, (RB) 8 À and (RX) 8 ÀPMOF with their respective D-isomer conjugates, r 8 À, (rB) 8 À and (rX) 8 ÀPMOF and found that there was no significant difference between each pair, as shown in Figure 2D for the (RX) 8 À and (rX) 8 ÀPMOF pair.