Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive beta-cyclodextrin (beta-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto beta-CD. Particularly, the structural details of acetalated beta-CD (Ac-beta-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-beta-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-beta-CD1 nanoparticles were prepared by a single oilin-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-beta-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-beta-CD nanoparticle could support cell survival and enhance cell viability.