Figures & data
Figure 1 ONT-forming lipid 1, PEG-lipid 2, and DOTA-lipid 3 for the construction of ONTs.
Notes: These lipids possess common octadecane hydrophobic spacer and oligoglycine moiety for the coassembly into ONTs via hydrophobic interaction and hydrogen bonds.
Abbreviations: DOTA, tetraazacyclododecane tetraacetic acid; ONT, organic nanotube; PEG, polyethylene glycol.
Figure 2 Synthesis of (A) PEG-lipid 2 and (B) DOTA-lipid 3.
Abbreviations: DMSO, dimethyl sulfoxide; DOTA, tetraazacyclododecane tetraacetic acid; PEG, polyethylene glycol.
Figure 3 Morphologies of ONTs and self-assemblies of 2 and 3 based on STEM observation.
Notes: (A) Mother ONT, (B) 5% PEG-ONT, (C) 10% PEG-ONT, (D) 20% PEG-ONT, (E) Self-assembly of 2, (F) Self-assembly of 3, (G) DOTA-ONT, and (H) PEGylated DOTA-ONT. The samples were negatively stained with 2% phosphotungstate, allowing the cylindrical nanochannels of the ONTs to be visualized because they were darker than the outer walls of the ONTs.
Abbreviations: DOTA, tetraazacyclododecane tetraacetic acid; ONT, organic nanotube; PEG, polyethylene glycol; STEM, scanning transmission electron microscopy.
Figure 4 Length distribution of mother ONTs and PEGylated ONTs.
Abbreviations: ONT, organic nanotube; PEG, polyethylene glycol.
Figure 5 Mean particle size of ONTs in water and PBS as measured by DLS.
Abbreviations: DLS, dynamic light scattering; ONT, organic nanotube; PBS, phosphate-buffered saline; PEG, polyethylene glycol.
Figure 6 Transmittance of 10% PEG-ONT and mother ONT dispersions in PBS buffer at room temperature.
Abbreviations: ONT, organic nanotubes; PBS, phosphate-buffered saline; PEG, polyethylene glycol.
Figure 7 DSC curves of ONTs and self-assembly of 2.
Abbreviations: ONT, organic nanotube; PEG, polyethylene glycol.
Figure 8 The XRD pattern of 10% PEG-ONT at RT and 170°C, and self-assembly of 2 at RT.
Notes: The data on the peaks means the measured d-spacing values. Peaks A (artifact) stem from the edge of beam stopper.
Abbreviations: ONT, organic nanotube; PEG, polyethylene glycol; RT, room temperature; XRD, X-ray diffraction.
Figure 9 Distribution of DOTA-ONT and PEGylated DOTA-ONT in mice.
Abbreviations: DOTA, tetraazacyclododecane tetraacetic acid; h, hour; ONT, organic nanotubes; PEG, polyethylene glycol; h, hour.
Figure 10 STEM images of plasma samples at (A) 5 min, (B) 1 h, (C) 6 h, and (D) 24 h after the injection of PEGylated DOTA-ONT.
Abbreviations: DOTA, tetraazacyclododecane tetraacetic acid; h, hour; min, minutes; ONT, organic nanotube; PEG, polyethylene glycol; STEM, scanning transmission electron microscopy.
Figure S1 pH-dependent self-assembly of DOTA-lipid 3.
Abbreviation: DOTA, tetraazacyclododecane tetraacetic acid.
Figure S2 Agglomeration of mother ONT in mouse plasma.
Abbreviation: ONT, organic nanotube.
Figure S3 Optical microscopic images of (A) 10% PEG-ONT, and (B) self-assembly of 2 at increased temperatures.
Notes: The self-assembly of 2 melted at 120°C, while 10% PEG-ONT kept the solid state before decomposing (color turns black) at 220°C.
Abbreviations: ONT, organic nanotube; PEG, polyethylene glycol.
Figure S4 DSC cycles of dry 10% PEG-ONT.
Abbreviations: DSC, differential scanning calorimetry; NF, not found; ONT, organic nanotube; PEG, polyethylene glycol.
Figure S5 STEM images and macroscopic appearance (insets) of (A) nontreated and (B) heat-treated 10% PEG-ONT in PBS buffer.
Notes: Freeze-dried 10% PEG-ONT (~6 mg) was untreated or treated at 170°C for 5 min, 5 mL of PBS buffer was added and the mixtures were sonicated for 5 min in a bath sonicator. Turbid dispersion indicated the phase separation of PEG-lipid 2 from 10% PEG-ONT and nanotube aggregated in PBS buffer. Dissociation of 2 did not significantly destroy the nanotube structure.
Abbreviations: min, minutes; ONT, organic nanotube; PBS, phosphate-buffered saline; PEG, polyethylene glycol; STEM, scanning transmission electron microscopy.
Table S1 The exothermic temperatures and enthalpies of PEGylated ONTs and self-assembly of 2 based on DSC measurement