Fig. 2. Synthesis, optimization, and characterization of Trpzip hydrogels.

a Chemical structures of Trpzip1 and Trpzip1-QV, with changes in amino acid sequence highlighted. The photograph depicts Trpzip1 and Trpzip-QV peptides dissolved in pure water at 1 mg/mL after 24 h at 37 °C. b Circular dichroism spectra of Trpzip1 (dashed line) and Trpzip-QV (solid line) in H₂O across a temperature range of 0–60 °C. c Transmission electron micrographs of Trpzip-QV nanofibers formed at pH 7. The scale is 200 nm (left) and 50 nm (right). Data is representative of two independent experiments. d Cryo-TEM of Trpzip-QV hydrogels (2% w/v in DMEM, pH 7) at 30 s and 24 h post-gelation at 37 °C. The scale is 50 nm (left) and 100 nm (right). Data is representative of two independent experiments. e Small angle neutron scattering profiles of Trpzip-QV hydrogels in deuterated DMEM at 1% w/v (far left), 3% w/v (center left), separate data fitting to the lamellae model fit, and the power law fit (center right), and the combined data fitting against the experimental scattering of 1% w/v Trpzip-QV hydrogels (far right). f Scanning electron micrographs of Trpzip-QV hydrogels (3% w/v, DMEM) at pH 14 and pH 7. Scale bars are 100 μm, 5 μm, 200 μm, and 10 μm, from left to right. Data is representative of two independent experiments. g Schematic of proposed self-assembly mechanism of Trpzip-QV peptide monomers into hydrogels.