New Method for Delivering Biologically Active Molecules into Algae Cells

GR-MoTrs could prove useful with many industrially significant or academically interesting species.

The Science

Algae can produce a wide variety of biofuels, chemical building blocks, nutrients, and proteins using sunlight as an energy source and carbon dioxide or other simple carbon compounds. DOE scientists at Lawrence Berkeley Lab have developed a new method to deliver radioactive or fluorescently labeled small molecules or protein probes into algal cells to monitor cellular messengers such as mRNA, gene expression or to develop biosensors. A molecular probe’s ability to pass through the cell membrane is often restricted by its water and lipid solubility. The new method overcomes these restrictions, enabling transport of molecules across the cell wall and membrane barriers. Researchers describe a general molecular method based on guanidinium-rich molecular transporters (GR-MoTrs) for bringing small and large cargos into algal cells. The transporter technology is broadly applicable and can be used for the delivery of labeled probes into algal cells for the development of sensitive biological assays for dynamic imaging of gene expression. The technique is being further developed to transport genetic materials and for probing changes in the carbon metabolism of these cells. These advances will enable scientists to improve algae as a tool for a wide variety of applications.

The Impact

This is the first example of GR-MoTr-mediated transport into any species of algae and notably involves efficient passage across cell wall and membrane barriers. Importantly, this method was shown to work with protein cargo, including a catalytically competent enzyme, in C. reinhardtii


Interest in algae has significantly accelerated with the increasing recognition of their potentially unique role in medical, materials, energy, bioremediation, and synthetic biological research. However, the introduction of tools to study, control, or expand the inner-workings of algae has lagged behind. Significantly, this method is shown to work in wild-type algae that have an intact cell wall. Developed using Chlamydomonas reinhardtii, this method is also successful with less studied algae including Neochloris oleoabundans and Scenedesmus dimorphus thus providing a new and versatile tool for algal research.  A molecular method to deliver, on variable scale, small molecules, probes, and biomacromolecules across the cell wall and membrane of wild-type algae, as required to probe and manipulate intracellular pathways in intact algae, would enable new opportunities in algal research and in the use of algae as photoautotrophic tools for synthetic biology. At the same time, such studies would serve to advance our understanding of biological barriers, a goal of central significance in the life sciences and agricultural and medical research.


Hyman, J. M., E. I. Geihe, B. M. Trantow, B. Parvin, and P. A. Wender. 2012 “A Molecular Method for the Delivery of Small Molecules and Proteins Across the Cell Wall of Algae Using Molecular Transporters,” Proceedings of the National Academy of Sciences (USA) 109(33), 225-230. DOI: 10.1073/pnas.1202509109.