An isochoric optical platform for interrogation of aqueous glass formation processes.

Aqueous vitrification (glass formation) processes are integral to modern cryopreservation, but experimental methods by which to study them are limited, particularly at the mL volume scales relevant to many biomedical applications. Here, we introduce an inexpensive custom optical platform, the isochoric vitrification cryo-macroscope (or "isovitriscope"), to supplement standard techniques with new qualitative and quantitative data streams. The platform consists of an LED light source, a isochoric (constant-volume) chamber with sapphire optical windows, and a camera, which can operate in two modes.

Limits of pressure-based ice detection during isochoric vitrification.

Vitrification under isochoric (constant-volume or volumetrically confined) conditions has emerged as an intriguing new cryopreservation modality, but the physical complexities of the process confound straight-forward interpretation of experimental results. In particular, the signature pressure-based ice detection used in many isochoric techniques becomes paradoxical during vitrification, wherein the emergence of a sharp increase in pressure reliably indicates the presence of ice, but avoidance of this increase does not necessarily indicate its absence. This phenomenon arises from the rich interplay between thermochemical and thermovolumetric effects in isochoric systems, and muddies efforts to confirm the degree to which a sample has vitrified.