Papers by Keyword: Stimuli-Responsive Hydrogel

Abstract: Providing realistic impressions about a virtual ambient for interaction with human’s auditory, visual, and tactile perception is one of the core challenges of modern imaging systems. However, particularly tactile displays with high spatial resolution implemented as a large-scale integrated microelectromechanical system are not yet realized. Here, we report on a multimodal display with thousands of actuator pixels, which generates both visual and tactile impressions of a virtual surface. The fully polymeric, monolithically integrated device consists of an actuator array made from poly(N-isopropylacrylamide). This material is a stimuli-responsive, particularly temperature-sensitive hydrogel. Controlling the actuator temperature via an optoelectrothermic interface between an upper and lower temperature the actuator can be switched from the swollen to the shrunken state (volume change up to 90%) in several hundred milliseconds. To benefit from this highly dynamic behaviour it is necessary to use a control unit which provides the required temperature changes also in the range of milliseconds. For characterizing the time behaviour of our optoelectrothermic control unit we use the change in transparency of PNIPAAm caused by the phase transition. In this paper we preferably discuss the time behaviour of the display devices.

Abstract: We have prepared a variety of biomolecule-responsive hydrogels by using biomolecular complexes as reversible crosslinking points. This paper describes two types of biomolecule-responsive hydrogels that undergo volume changes in response to target biomolecules, which were prepared using biomolecular complexes such as antigen-antibody complexes and saccharide-lectin complexes. One is a biomolecule-crosslinked hydrogel that can swell in response to a target biomolecule and the other is a biomolecule-imprinted hydrogel that can shrink. The antigen-responsive hydrogels as biomolecule-crosslinked hydrogels swelled in the presence of a target antigen due to the dissociation of antigen-antibody complexes that played a role as reversible crosslinking points. On the other hand, the tumor marker glycoprotein-responsive hydrogels as biomolecule-imprinted hydrogels shrank in response to a target glycoprotein due to the complex formation between ligands (lectin and antibody) and the target molecule (saccharide and peptide chains of glycoprotein). This paper focuses on synthetic strategy of the biomolecule-responsive hydrogels and their responsive behavior for target biomolecules.