Abstract:
Size and surface charge of nanoparticles have important impacts on drug delivery process. Conventional preparation and tuning of particle features e.g. surface charge are difficult and time consuming. In this work, a pH-responsive spherical drug-loaded nanoparticles was prepared by encapsulating a hydrophobic drug
β-carotene in a biocompatible copolymer, poly(ethylene glycol)-
b-polycaprolactone (PEG-
b-PCL) and poly(2-(dimethylamino) ethylmethylacrylate)-
b-polycaprolactone (PDMAEMA-
b-PCL), via flash nanoprecipitation (FNP) method in a multi-inlet vortex mixer (MIVM). Particle size and surface charge of nanoparticles at different pH values were investigated. By changing the feed ratio of the two polymers, surface charge of the nanoparticles can be tuned from +32.4 mV to −4.7 mV. Meanwhile, as the ratio of PEG-
b-PCL was increased, the surface charge decreased due to the decrease of amine content from the PDMAEMA block. The size of the nanoparticles can be adjusted by changing the feed flow rate into the MIVM by which the flow rate of organic phase (
v1) was kept at 12 mL/min and the flow rate of water (
v2) was increased from 24 mL/min to 96 mL/min, the nanoparticles size was decreased from 126.6 nm to 62.7 nm. When
v1:
v2 was 6∶24, 12∶48, 24∶96, respectively, the nanoparticles size can be reduced from 107.5 nm to 77.3 nm. The nanoparticle is stable for 25 d at pH=7.4. By the strategy of flash nanoprecipitation, the spherical drug-loaded nanoparticles can be rapidly prepared, particle size and surface charge can be accurately modulated easily and provided potential applications for cancer diagnosis and treatments in the future.