Prof. Saumya Saurabh, New York University, "Using Light to Decipher Life: Mapping the Chemical Environment Inside Biomolecular Condensates"

Cells organize their chemistry in biomolecular condensates, compartments that form without a

membrane. We know what goes into these compartments. We know far less about the chemical

environment they create inside. My group develops optical methods to map that environment with

spatial resolution, from purified droplets to living bacteria.

Fluorescence lifetime imaging and custom multiparametric dyes reveal that condensate interiors

are not uniform liquids. They are mosaics of distinct chemical niches that differ in polarity,

hydrogen bonding and crowding. These niches decide where molecules partition and how reactions

proceed.

I will show how this chemical view explains RNA condensation, where small molecules

reorganize RNA into condensed phases with new properties. I will then turn to bacteria, where

condensates act as stress responders. They sense physical changes such as heat and reorganize to

couple the environment to cell-cycle decisions.

Together, these studies establish condensates as tunable chemical reactors and point to new ways

to control bacterial physiology.