HA-P5 was synthesized by dissolving 5 mg of HA (10 kD) powder in 45 mL of Milli-Q water under magnetic stirring for 15 min at 80 °C when the solution turned transparent. EDC/NHS was dissolved in Milli-Q water and stirred for 30 min to get the EDC/NHS (20 mM/20 mM) solution. Next, the transparent HA solution was incubated with EDC/NHS solution at 30 °C for 60 min. Then, 5 mL P5 (1 mg/mL) was added to the reaction solution dropwise for 12 h at 40 °C. Finally, the solution was filtered with a 0.22 μm filter membrane to obtain the HA-P5 solution.
Transmission electron microscopy (TEM) samples were prepared by dispersing the pieces onto a holey carbon film on copper grids. The micrographs were obtained on a Tecnai G220 (Shimadzu, Japan) at 200 keV and Atomic Force Microscope (AFM) (Bioscope Catalyst/Multimode, USA). A dynamic light scattering (DLS) particle size analyser (Malvern 2000, USA) was used to determine the hydrodynamic diameters of the particles. The interaction between HA and P5 was detected by an infrared spectrometer (VERTEX70, USA) and zeta potential analyzer (Malvern 2000, USA). All measurements were performed at room temperature unless otherwise mentioned.
Transmission electron microscopy (TEM) samples were prepared by dispersing the pieces onto a holey carbon film on copper grids. The micrographs were obtained on a Tecnai G220 (Shimadzu, Japan) at 200 keV and Atomic Force Microscope (AFM) (Bioscope Catalyst/Multimode, USA). A dynamic light scattering (DLS) particle size analyser (Malvern 2000, USA) was used to determine the hydrodynamic diameters of the particles. The interaction between HA and P5 was detected by an infrared spectrometer (VERTEX70, USA) and zeta potential analyzer (Malvern 2000, USA). All measurements were performed at room temperature unless otherwise mentioned.