Biotechnology: Engineering human cells to become transparent

Human cells that are capable of becoming transparent in laboratory experiments are reported this week in Nature Communications.

Many cephalopods are capable of changing how their skin transmits, absorbs and reflects light, which can be used for the purposes of camouflage. The female Doryteuthis opalescens squid also uses this mechanism in attempts to avoid acts of aggression by switching a stripe on its mantle from nearly transparent to white. In both cases, the process is controlled by a series of cells called leucophores, which contain proteins called reflectins that are capable of altering the optical properties of the cell.

Inspired by adaptive cephalopod skin cells, Alon Gorodetsky and colleagues set out to design and engineer human cells that are capable of controllable and reversible transparency. The authors selected human embryonic kidney cells and engineered them to express the protein reflectin A1, found in the mantle of D. opalescens. They then studied whether the expression of the squid protein affected the human cells’ interaction with light and whether these properties could be controlled. Using different concentrations of sodium chloride solution in laboratory experiments, they were able to alter the levels of transparency of the engineered cells.

The authors conclude that their findings may improve understanding of a wide range of biological systems, by allowing clearer imaging of processes taking place inside living cells and tissues.