Elizabeth A. Moschou

Fluorescence glucose detection: Advances toward the ideal in vivo biosensor

The importance of glucose monitoring for in vivo as well as for ex vivo applications has driven a vast number of scientific groups to pursue the development of an advanced glucose sensor. Such a sensor must be robust, versatile, and capable of the long-term, accurate and reproducible detection of glucose levels in various testing media. Among the different configurations and signal transduction mechanisms used, fluorescence-based glucose sensors constitute a growing class of glucose sensors represented by an increasing number of significant contributions to the field over the last few years. This manuscript reviews the progress in the development of fluorescence based glucose sensors resulting from the advances in the design of new receptor systems for glucose recognition and the utilization of new fluorescence transduction schemes.

Stimuli-responsive hydrogels based on the genetically engineered proteins: Actuation, drug delivery and mechanical characterization

Herein, we describe a biomimetic approach aimed at the development of synthetic biohybrid materials inspired by natures sensing and actuating mechanism of action. The biomaterials are based on the incorporation of the hinge-motion binding protein calmodulin (CaM) and its low affinity ligand phenothiazine (TAPP) within the bulk of an acrylamide hydrogel network, which is accomplished through covalent binding. At the initial state and in the presence of Ca 2+ ions, CaM interacts with TAPP creating chemical (non-covalent) cross-links within the bulk of the hydrogel, forcing the material to assume a constrictive configuration. Upon the removal of Ca 2+ , CaM releases TAPP, breaking the non-covalent cross-links within the bulk of the hydrogel and letting the material relax into a swollen state. The same type of effect is observed when a higher affinity ligand for CaM, like chlorpromazine (CPZ), is employed. In the presence of CPZ, the protein releases TAPP and binds CPZ, allowing the biomaterial to swell into a relaxed state. This swelling response of the biomaterial is reversible, and is directly related to the levels of CPZ used. The sensing and subsequent actuating mechanism of the CaM-based stimuli-sensitive hydrogels makes them suitable for a variety of applications, including sensing, mechanical actuation, high-throughput screening, and drug delivery. Additionally, it is shown that the CaM-based stimuli-sensitive hydrogels developed present unique mechanical properties, suitable for integration within microfluidics and MEMS structures. It is envisioned that these biomaterials will find a number of applications in a variety of fields, including drug delivery.