Characterization of cross-linking vehicle effect on surface interactions between pH-sensitive drug delivery vehicle and mucin layers by colloid probe atomic force microscopy

Abstract

In order to control the interaction between the artificial mucin layer and pH-responsive shells of the core-shell drug delivery vehicles, two types of cross-linking agents with different molecular weights were added to the shells. The surface interaction between each vehicle and mucin was measured by colloid probe atomic force microscopy under different pH conditions. By adding 0.08 mol% cross-linking agents, the shell swelling phenomena at pH > 6 were maintained. Addition of a low molecular weight cross-linking agent (TEGDMA) reduces the interaction distance of repulsive force during approaching process. Addition of a high molecular weight cross-linking agent (PEGDMA) increased the interaction distance of repulsive force. A long interaction distance of attractive force during the separating process disappeared at pH = 6 after the addition of PEGDMA. However, TEGDMA addition maintained the long interaction distance of attractive force at pH = 8, which suggested that the vehicle might remain for an extended duration in the small intestine.