A liquid crystal image-preserving tunable filter (IPTF) for cell microscopy is proposed. Recent developments in birefringent liquid crystal technology should make it possible to construct an inexpensive, large-aperture tunable filter that ranges from 350 to 3000 nm in a few milliseconds with no moving parts and a bandpass of 6 nm. There are a great number of microscopy optical probing techniques used to study the dynamics, the chemical processes and the membrane transport mechanisms of the living cell. The efficacy of many of these techniques depends strongly on ability to detect shifts in the excitation, emission or absorption spectra by monitoring narrow bandwidths of light. As more probing techniques are developed and systems become more complicated, automation, versatility, speed, and convenience will be increasingly important. An IPTF would help to advance the art in many of these areas. Phase I research will include construction of a prototype with existing liquid crystal technology and performing a feasibility study involving the acquisition of images of calcium ion distribution of a cell injected with INDO-1. Image analysis and comparison with images taken with standard interference filters will indicate aspects of current liquid technology that need developing in Phase II. It will also indicate practical considerations for design of a versatile, convenient microscope accessory.
