On-off Control of Drug Permeation through Antigen-Responsive Gels

Introduction Stimuli-responsive gels that exhibit swelling/shrinking changes in response to environmental changes such as pH and temperature have many future opportunities as suitable materials for mimicking biomolecules and designing smart systems in the biochemical and biomedical fields [1]. For example, self-regulated drug delivery can be achieved by loading a drug within pHand temperature-responsive gels. However, there are very few studies on molecule-responsive gels that undergo volume changes in response to a target molecule in spite of their potential applications in biomedical fields [2-6]. We have prepared novel antigen-responsive gels that have molecular recognition functions, based on the strategy that specific interactions such as antigen-antibody bindings can be used as stimuli-responsive cross-linking points [7, 8]. In addition, tumor-marker-responsive gels were synthesized by biomolecular imprinting in which lectin and antibody were utilized as ligands for a template tumor marker glycoprotein [9]. In this paper, a method for preparing antigen-responsive gels is reported that involves simple means of introducing stimuli-responsive cross-linking structures. This paper focuses on the controlled permeation of model drugs through the antigen-responsive gels. We discuss the effect of semi-interpenetrating polymer network (semi-IPN) in the gels on their antigen-responsive swelling behavior and controlled drug permeation.