Aldehyde-like non-toxic fixative

Understand and mimic the effects of glutaraldehyde prior to ethylene glycol, to find a non-toxic alternative.

The attempt of using glutaraldehyde-based fixative, then slowly perfuse increasing concentrations of ethylene glycol over several hours in a manner similar to techniques used for whole organ cryopreservation (using 65% w/v ethylene glycol, and reaching −135 °C), has resulted in synaptic-granularity preservation (link).

The 'aldehyde-like non-toxic fixative' would be a fixative that in would be derived by understanding why does the glutaraldehyde worked, by analyzing the overall changes that brain tissue undergoes under the effect of it, and researching all chemicals similar to it, to discover a similar non-toxic cryoprotectant.