Chip-Based Scanning Nano-Calorimeter for Protein Stability Analysis in Biosensor Membranes

A nanocalorimeter is presented consisting of a silicon chip with germanium thermistors. Thermistors patterned on a silicon nitride membrane provide highly sensitive thermal measurements. Differential measurements can be performed by comparison with thermistors patterned on the bulk- silicon. Temperature scanning measurements enable to determine the phase transition temperatures(Tm) of various phase-change materials. We have demonstrated this for liquid crystals, phospholipid vesicles and the denaturation of the enzyme glucoseoxidase (GOx). Nano differential scanning calorimetry (nano DSC) of glucoseoxidase is performed both in aqueous solution and in hydrogels.