Effect of Degrees of Substitution on Physicochemical Properties of 2-Hydroxypropyl Trimethyl Ammonium Chloride Chitosan

2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC), a cationic biopolymer derived from chitosan, has been described as a vehicle for gene and drug delivery and an excellent sustainably-released biomedical material for broad applications. This study aimed to explore the relationship between degree of substitution (DS) of HACC and the properties of HACC-sodium tripolyphosphate nanoparticles (HACC-TPP-NPs). A series of the HACCs with different DSs were synthesized by using prior protection of amino group with benzaldehyde. The effect of DSs on water solubility, mean sizes and zeta potentials of the HACCs were determined. It was found that the HACCs had good water solubility which was increased significantly with increasing DS percentage. The DS percentage of HACCs was found to be a critical factor for forming the HACC-TPP-NPs, when their DSs were 60.19% and 68.95%, HACC-TPP-NPs exhibited a spherical outline and uniform size and they were distributed evenly without obvious agglomeration and with the mean size of about 300 nm. The HACCs with 60.19% and 68.95% of DS could be a potential biomaterial as gene and drug delivery, and the HACC-TPP-NPs could be a drug delivery carrier with immense potential in medical applications.