*3.4. Particle Size and Zeta Potential Measurement*

The z-average diameter, polydispersity index (PDI), and zeta potential of CS NPs and CS@CBLO NPs were measured by dynamic light scattering (DLS) using a Brookhaven 90Plus nanoparticle size analyzer (Brookhaven Instruments, Holtsville, NY, USA). An approximately 2 mg sample was suspended in 5 mL of water using magnetic agitation for mono-dispersion, and then the sample was taken to fill the disposable zeta potential cuvettes for size distribution and surface charge analysis. All the tests were performed in triplicate.
