Abstract: Aspects of pH responsive polymers are described. One exemplary aspect is a pH responsive GelMA polymer comprising a gelatin type A with selectively modified and unmodified functional groups. For example, this polymer may comprise: modified carboxyl groups, modified hydroxyl groups, unmodified carboxyl groups, unmodified hydroxyl groups, and unmodified amine groups; carboxyl and hydroxyl groups that have been methacrylated; or carboxyl, hydroxyl, and amine groups that were not methacrylated, wherein the modified and unmodified functional groups of Polymer A may be selected by controlling a pH level of its synthesizing reaction. Another exemplary aspect is a pH responsive GelMA polymer comprising a gelatin type B with selectively modified amine groups, modified hydroxyl groups, unmodified carboxyl groups, unmodified, hydroxyl groups, and unmodified amine groups. Related apparatus, compositions, methods, polymers, and systems are described.

Abstract: The present invention presents a device and methods of use thereof in combined electrohydrodynamic concentration and plasmonic detection of a charged species of interest using a flow-through nanohole array. The device comprises microchannels, which are linked to a substrate with arrays of through nanoholes, wherein the substrate comprises two layers, wherein one of the layers is made of insulator material and one of the layers is made of metal, whereby induction of an electric field across the nanohole array results in the species of interest concentrating inside the nanoholes and in the vicinity of the nanohole arrays. The induction of an electric field is achieved by means of an external electric field source, which is applied to the fluid containing the species of interest, resulting in electroosmotic (EO) flow. An additional pressure driven fluid flow in the microchannels, co-directional to the EO flow is applied by external means.

Abstract: The present invention presents a device and methods of use thereof in combined electrohydrodynamic concentration and plasmonic detection of a charged species of interest using a flow-through nanohole array. The device comprises microchannels, which are linked to a substrate with arrays of through nanoholes, wherein the substrate comprises two layers, wherein one of the layers is made of insulator material and one of the layers is made of metal, whereby induction of an electric field across the nanohole array results in the species of interest concentrating inside the nanoholes and in the vicinity of the nanohole arrays. The induction of an electric field is achieved by means of an external electric field source, which is applied to the fluid containing the species of interest, resulting in electroosmotic (EO) flow. An additional pressure driven fluid flow in the microchannels, co-directional to the EO flow is applied by external means.