Mucoadhesion vs mucus permeability of thiolated chitosan polymers and their resulting nanoparticles using a quartz crystal microbalance with dissipation (QCM-D).

The aim of this present study was to evaluate the combination properties between mucoadhesion/mucus permeability of thiolated chitosans (TC) and their resulting nanoparticles using a quartz crystal microbalance with dissipation (QCM-D). The QCM-D experiments were conducted at pH 4 or 6.8 to assess the interaction between thiolated polymers, with low (TCL), medium (TCM) and high (TCH) contents of free thiol groups, and native porcine gastric mucin (NPGM). TCL was chosen for further carriers as it showed higher permeability into the NPGM layer compared to TCM and TCH. In this study, we describe a formulation of a novel carrier comprised by positively charged TCL, negatively charged DNA and degradable oligopeptide-modified poly(β-amino ester)s (PBAEs), which were employed in order to approach for tuning particle size and surface charge of complexes. TCL/PBAE complexes with or without DNA were characterized using dynamic light scattering. Mechanism of adsorption or permeation of the TCL/PBAE/DNA complexes into the NPGM barrier was investigated with QCM-D, which is a highly sensitive technique for studying nanomechanical (viscoelastic) changes of the substrates. This work might provide that the QCM-D technique would be a promising method to monitor the dynamic behaviour between complexes and NPGM.