Supporting Information. Lipids for Liposome Shielding by 18 F-Radiolabeling. and Positron Emission Tomography

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1 Supporting Information Comparison of Linear and Hyperbranched Polyether Lipids for Liposome Shielding by 18 F-Radiolabeling and Positron Emission Tomography Karolin Wagener, Matthias Worm, Stefanie Pektor, Meike Schinnerer, Raphael Thiermann, Matthias Miederer, Holger Frey and Frank Rösch Content S1. Polyether lipid characterization a. Determination of molecular weights M n by 1 H NMR spectroscopy b. Spectra of polyether lipids S2. Radiolabeling a. [ 18 F]F-TEG-N 3 b. Polyether lipids S3. Liposome formation S4. Liposome characterization S5. Liposome stability S6. Animal studies a. Positron emission tomography (PET) studies b. Biodistribution studies S7. Liposomes shielded by cholesterol-anchored polyethers References 1

2 S1. Polyether lipid characterization a. Determination of molecular weights M n by 1 H NMR spectroscopy Molecular weights M n of polyether lipids given in this study were determined from the corresponding 1 H NMR spectra measured in pyridine-d 5. To this end, the integral of the BisHD initiator protons (2xCH 3, 6H) at δ = 0.91 ppm was normalized to a value of 6. The degree of polymerization was calculated from the integral of the polyether backbone signals between δ = ppm by first subtracting underlying initiator protons (4xCH 2 O+CHO, 9H) and then dividing the resulting value (total number of polyether backbone protons) by the number of protons per monomer repeating unit (PEG = 4, hbpg = 5). In case of hbpg lipids, alternatively the integral of hydroxyl proton signals at δ = ppm can be used to read out the degree of polymerization as each repeating unit corresponds to a single hydroxyl proton in the structure. b. MALDI-ToF and NMR Spectra of polyether lipids Figure S-1: MALDI ToF MS spectrum of BisHD-linPG 19. KTFA salt was added, using CHCA as a matrix. 2

3 Figure S-2: 13 C NMR spectrum of BisHD-hbPG 63 with alkyne moiety, measured in pyridine-d 5 at 100 MHz. Figure S-3: Diffusion-ordered NMR spectrum (DOSY NMR) of BisHD-hbPG 32 -alkyne measured in DMSO-d 6. 3

4 Figure S-4: 1 H NMR spectrum of BisHD-PEG 56 -alkyne measured in CD 2 Cl 2 at 400 MHz. Figure S-5: Monomodal SEC trace of BisHD-PEG 56 using DMF as an eluent and RI detection. 4

5 S2. Radiolabeling Subsequent to the click reaction, we removed copper using a Chelex 100 resin (obtained from Bio-Rad), which (according to the supplier) exhibits uniquely high selectivities for metal ions. In order to investigate the efficiency, we added sodium sulfide to a sample of the purified reaction mixture and to a sample prior to the removal of copper. In the first case, we observed no precipitation of copper sulfide, whereas in the second case we obtained a darkish precipitate of copper sulfide. a. [ 18 F]F-TEG-N 3 Figure S-6: Front panel of the semi-automatic custom modular system used for the synthesis of [ 18 F]F-TEG-N 3. 5

6 Figure S-7: Radio-TLC of the [ 18 F]F-TEG-N 3 synthesis after 10 min with a RCY of 91 %. 6

7 b. Polyether lipids Figure S-8: Radio-TLCs of the radiolabeling of A BisHD-PEG 56 -alkyne (reaction time 10 min, RCY 97 %), B BisHD-hbPG 32 -alkyne (reaction time 10 min, RCY 96 %) and C & D BisHD-hbPG 63 -alkyne (C: reaction time 1 min, RCY 86 %; D: reaction time 10 min, RCY 98 %) with [ 18 F]F-TEG-N 3 via CuAAC. Reg #1 corresponds to the respective polyether lipid, Reg #2 attributes to [ 18 F]F-TEG-N 3. Different migration distances of [ 18 F]F-TEG-N 3 are explained by different running distances of the mobile phase. S3. Liposome formation 7

8 Figure S-9: Comparison of the size reproducibility of identical batches of BisHD-PEG 56 -shielded liposomes extruded by hand (left side) or automatically (right side). n=3. Sizes were determined via dynamic light scattering (DLS). 8

9 S4. Liposome characterization Figure S-10: Cryo-TEM images of BisHD-PEG56-shielded liposomes (A-D) and BisHD-hbPG32-shielded liposomes (E-H), showing unilamellar liposome structure. 9

10 Figures S-11: D app plotted against q 2 data and thereof calculated hydrodynamic radii of BisHD-PEG 56 -shielded liposomes (A), BisHD-hbPG 32 -shielded liposomes (B) and BisHD-hbPG 63 -shielded liposomes (C). 10

11 S5. Liposome stability Figure S-12: Examination of the temperature stability of BisHD-PEG 56 -shielded liposomes via dynamic light scattering. The hydrodynamic radius (<R -1 h > -1 z ) of BisHD-PEG 56 -shielded liposomes was determined via dynamic light scattering at 20 C. Subsequently, the sample chamber was heated in steps of 5 C until 50 C were reached. At each temperature step the size of the liposomes was measured. Figure S-12 shows the development of the hydrodynamic radius of the liposomes depending on temperature. The data show that the size of the liposomes fluctuates only marginally, confirming that the liposomes are stable between 20 C and 50 C. No degradation is observed that would lead to smaller hydrodynamic radii. 11

12 Figure S-13: Autocorrelation functions of BisHD-PEG 56 -shielded liposomes (A), BisHD-hbPG 32 -shielded liposomes (B) and. BisHD-hbPG 63 (C). Blue curves are acquired shortly after the manufacturing of the liposomes. Red curves are acquired at least one month later (A, B: 4 months later; C: 1 month later). An aliquot of the liposomes (BisHD-PEG 56 -shielded, BisHD-hbPG 32 -shielded and BisHDhbPG 63 -shielded) in PBS buffer used for the animal experiments was stored at 4 C until complete disappearance of radiation. Subsequently, the size of the liposomes was determined via dynamic light scattering (DLS). Following these experiments the samples were stored at 4 C for at least one month and were then re-measured via DLS. Figure S-13 shows overlays of the two measurements of the same liposome sample, each at different time points. Since all curves overlay and the shape of the curves did not change, this strongly indicates that the liposomes are stable within the respective period of time (A, B: 4 months; C: 1 month). 12

13 S6. Animal studies a. Positron emission tomography (PET) studies To track the pharmacokinetic profile during the first hour after intravenous administration of the 18 F-radiolabeled, polyether-shielded liposomes and the respective non-liposomal polymers, time activity curves were determined by defining volumes of interest (VOIs) around important organs and quantifying the amount of radioactivity inside the VOIs (Fig. S-14, S-15). Figure S-14: Time activity curves (TACs) of the accumulation of BisHD-hbPG F (A) and BisHD-PEG F (B) in organs of interest of male C57BL/6 mice. 13

14 Figure S-15: Time activity curves (TACs) of the accumulation of 18 F-radiolabeled BisHD-PEG 56 -shielded liposomes (A), BisHD-hbPG 32 -shielded liposomes (B) and BisHD-hbPG 63- shielded liposomes (C) in organs of interest of male C57BL/6 mice. Figure S-16: Accumulated activity in relevant organs of male C57BL/6 mice 1 h (A) and 4 h (B) after injection of the 18 F-radiolabeled, differentially shielded liposomes and the respective polymers determined by defining volumes of interest (VOIs) around important organs and quantifying the amount of radioactivity inside the VOIs. 14

15 b. Biodistribution studies Table S-1: Ex vivo biodistribution data for polyether lipids and liposomal formulations in male C57BL/6 mice. organ BisHD-PEG 56 BisHDhbPG 32 BisHD- PEG 56 liposomes (1 h) BisHD- PEG 56 liposomes (4 h) BisHDhbPG 32 liposomes (1 h) BisHDhbPG 32 liposomes (4 h) BisHDhbPG 63 liposomes (1 h) BisHDhbPG 63 liposomes (4 h) lung 5.32± ± ± ± ± ± ± ±0.58 blood 14.51± ± ± ± ± ± ± ±0.86 liver 11.42± ± ± ± ± ± ± ±3.24 spleen 3.10± ± ± ± ± ± ± ±16.64 kidney l 3.79± ± ± ± ± ± ± ±0.91 kidney r 3.90± ± ± ± ± ± ± ±0.87 muscle 0.34± ± ± ± ± ± ± ±0.06 heart 2.97± ± ± ± ± ± ± ±0.56 urine ± ± ± ± ± ± ± ±0.27 intestine 1.42± ± ± ± ± ± ± ±0.69 testes 0.58± ± ± ± ± ± ± ±0.07 lymph nodes 0.92± ± ± ± ± ± ± ±0.76 inguinal a n=5 n=5 n=5 n=3 n=5 n=3 n=5 n=5 urine n=3 urine n=4 urine n=4 urine n=3 urine n=5 urine n=2 urine n=4 urine n=4 a Since liposomes were injected intravenously, the distribution to several lymph nodes should be comparable. The inguinal lymph nodes were chosen with respect to further studies with tumor-bearing mice, to evaluate the accumulation of liposomes into tumors caused by the EPR-effect as well as drug targeting into tumors. In our subcutaneous tumor models the tumor cells will be injected into the flank of the mouse and will then be drained by the inguinal lymph node. S7. Liposomes shielded by cholesterol-anchored polyethers (previously published results) In order to facilitate the comparison between the current liposomes shielded by BisHD-anchored polyethers and the liposomes shielded by cholesterol (Ch)-anchored polyethers, Figure S-17 shows the PET images of the liposomes shielded by cholesterol (Ch)-anchored polyethers. The evaluation of these liposomes is described in detail in a previous report. 1 15

16 Figure S-17: Coronal MIPs at different time points (left column: 0-3 min p.i., right column: min p.i.) for Cholesterol-PEG F liposomes (A, B) and Cholesterol-PEG 30 -hbpg F liposomes (C, D). Liposomes contained 20 mol% of the shielding polyether lipid. he: heart, lu: lung, ve: vein, li: liver, in: intestine, bl: bladder, sp: spleen. References [1] Reibel, A. T.; Müller, S. S.; Pektor, S.; Bausbacher, N.; Miederer, M.; Frey, H.; Rösch, F. Fate of Linear and Branched Polyether-Lipids in Vivo in Comparison to Their Liposomal Formulations by 18 F-Radiolabeling and Positron Emission Tomography. Biomacromolecules 2015, 16,