Fig. 5. In vivo biodistribution of nanodiscs in naïve BALB/c nude mice.

Animals were administered fluorescent nanodiscs via the tail vein and imaged 1, 6, and 24 h post injection. Imaging of the Cy5 conjugated MSP protein was performed using 620 nm excitation and 670 nm emission filters and the lipophilic DiI dye (loaded into the bilayer) using 540 nm excitation and 620 nm emission filters. a Comparison of cNW11 and linear NW11 distributions. DiI intensity, localised to regions of fat deposits, increases with time reaching a peak at 24 h post injection for both linear and cyclised nanodiscs. Cy5 distribution demonstrates clearance of both linear and cyclic nanodiscs through the GI tract at early time points. Ex vivo analysis of clearance organs demonstrates higher linear NW11 protein in the liver 24 h post injection compared to cNW11 but lower DiI suggesting increased metabolism. Ex vivo organ fluorescence data is presented as mean normalised radiant efficiency values (n = 3) with standard deviation error bars. b Comparison of cNW15 and cNW7 distributions. Both cNW15 and cNW7 demonstrate similar distributions to cNW11. Ex vivo analysis demonstrates higher cNW7 protein in the liver compared to cNW15, similar to the trend observed between linear NW11 and cNW11. Statical analysis was performed using unpaired two-tailed t-tests, *p-value ≤ 0.05, **p ≤ 0.005. Cy5 linearNW11 vs cNW11 kidneys p = 0.04, liver p = 0.002, GI p = 0.005; DiI linearNW11 vs cNW11 kidneys = 0.04; Cy5 cNW7 vs cNW15 liver p = 0.05. c Graphical representation of a fluorescent nanodisc demonstrating the Cy5 (blue) conjugated to the MSP (orange) lysine sidechain, and the lipophilic DiI dye (magenta) located within the POPC lipid bilayer (grey).