U dict

Proton nuclear magnetic resonance (¹H NMR) spectroscopy was conducted on a Varian Unity 400 MHz spectrometer using deuterated water (D₂O) as the solvent and a sample concentration of approximately 4 mg mL^–1. Differential interference contrast (DIC) and fluorescence microscopy images of HA particles and capsules were obtained using an inverted Olympus IX71 microscope equipped with a DIC slider (U-DICT, Olympus), a UF1032 fluorescence filter cube, and a 100× oil immersion objective (Olympus UPFL20/0.5NA, W.D1.6). Transmission electron microscopy (TEM) images were taken using a FEI Tecnai TF20 instrument with an operation voltage of 200 kV. Atomic force microscopy (AFM) experiments were performed with a JPK NanoWizard II BioAFM. Typical scans were performed in intermittent contact mode with MikroMasch silicon cantilevers (NSC/CSC). The film thickness of the capsules was analyzed using JPK SPM image processing software (version V.3.3.32).

A lab-made dove prism-type TIRF setup, resembling the apparatus previously used in our group, but with some modifications, was employed (Additional file 1: Fig. S2) [38 (link)]. The setup consisted of an Olympus BX53 upright microscope (Olympus Optical Co., Ltd., Tokyo, Japan) equipped with a × 100-oil type objective lens with numerical aperture 1.4 (Olympus, UPlanSApo) and a DIC slider with Nomarski prism (Olympus, U-DICT). The dove prism with the sample was placed on the prism holder. Light sources from 532-nm-(Changchun New Industries Optoelectronics Tech. CO., Ltd., Jilin, China) and 405-nm-wavelength lasers (COMPACT-30G-405, World Star Tech., Toronto, ON, Canada) were directed to the prism with the help of mirrors to obtain total internal reflection and to produce an evanescent field layer on the interface. An electron-multiplying cooled charge-coupled device camera (EM-CCD, 512 × 512 pixels imaging array, iXon Ultra, Andor, Belfast, Ireland), along with a 575/15 nm band-pass filter (Semrock, Rochester, NY, USA) placed on the optical path of the microscope, was used to acquire the fluorescence images. MetaMorph 7.8.12.0 software (Molecular Devices, LLC, Sunnyvale, CA, USA) was used to control the image acquisition, shutter speed, and exposure time of the camera.