Shape memory alloy activated high-pressure optical cell for biophysical studies

Abstract

The high-pressure optical cell (HPOC) originally designed by A. A. Paladini and G. Weber [Rev. Sci. Instrum. 52, 419 (1981)] has been widely used in biophysical research. However, the original HPOC only allows for the observations of optical properties of single samples, thus limiting the data which researchers can obtain. The objective of this article is to demonstrate a new HPOC design, which enables researchers to introduce an additional component to the original sample for optical observation of biochemical reactions in real time, while all the components are under pressure. The core of this new design is the introduction of the shape memory alloy activated stopper/mixing mechanism, which separates different biological samples until the experimenter is ready to mix them. A urethane stopper separates the two samples, which are sealed in a dual chamber cuvette. The cuvette is suspended in the mid chamber, so that the pressure can be transmitted to both sides of the cuvette equally. Once an electric current is transmitted through the electrical plugs, the shape memory alloy is heated and moves the urethane stopper away from the neck of the cuvette. In addition, the shape memory alloy achieves a pumping action, which facilitates the mixing of the two samples. A multiple-chamber cuvette capable of mixing three components is also designed. Some preliminary feasibility testing has been done, and a stainless steel HPOC prototype has been built to validate the design.