Nx10 instrument

Field emission scanning electron microscopy (FESEM) images were obtained using JSM-7100F and JSM-7800F instruments (JEOL). JEM-2100F and JEM-ARM 200 F instruments (JEOL) were used to acquire transmission electron microscopy (TEM) images. UV-vis-NIR absorption spectra were acquired using a spectrophotometer (Shimadzu UV-3600). 3D tomography images were obtained using Talos F200X. A NX10 instrument (Park systems) was used to acquire AFM images and height profiles. X-ray diffraction (XRD) patterns of the nanostructures were characterized using a Rigaku Ultima IV. The electrochemical measurements were performed using an Auto Lab AUT12.

Field-emission scanning electron microscopy (FE-SEM) images were obtained using JSM-7100F and JSM-7800F instruments (JEOL) at the Chiral Material Core Facility Center of Sungkyunkwan University. JEM-2100F and JEM-ARM 200 F instruments (JEOL) were used to acquire transmission electron microscopy (TEM) images. UV-vis-NIR absorption spectra were acquired using a spectrophotometer (Shimadzu UV-3600). 3D tomography images were obtained using a Talos F200X. An NX10 instrument (Park systems) was used to acquire AFM images and height profiles.

Type I collagen from rat tail (Discovery Labware Inc., Bedford, MA) was diluted in 10 mM phosphate buffered saline (PBS) pH 7.4 to a final concentration of 2.0 mg/mL and incubated at 37 °C for 2 hours for fibril self-assembly. A sample volume of 20 μL was deposited on a 1 cm × 1 cm square of freshly cleaved mica (Ted Pella Inc., Redding, CA) and incubated at room temperature for 15 min. Then the surface of the sample was washed with 1 mL of deionized water and left to dry at room temperature for 1 h before being imaged. The samples were imaged by an NX-10 instrument (Park Systems, Suwon, South Korea) in non-contact mode with PPP-NCHR tips (nominal force constant 42 N/m; 330 kHz frequency; Nanosensors, Neuchatel, Switzerland). Images were not filtered and minimal processing was conducted using XEI (Park Systems, Suwon, South Korea).