Organic nanoshells help detect biotoxins in humans

Biological sensors capable of detecting previously invisible biotoxins and chemical warfare agents in the human body are being developed using nanoshells of organic materials.

The hollow nanoshells, being developed at the University of Arizona, are filled with indicator dyes and placed in cells. Prof Craig Aspinwall, who is leading the research, said his method is opening up an entirely new world of molecules for researchers to look at.

The unique process creates the sensors by synthesising nanoshells of phospholipids – a principal component of cell membranes – and filling them with indicator dyes made from enzymes and proteins. The hollow structure of the sensors allows them to carry toxic or water-soluble dyes without affecting cellular processes.

The sensors are then put into cells, either by injection or natural uptake, where the dyes react with ions, molecules and groups of molecules.

These reactions report the presence of specific ions or molecules to researchers using standard fluorescence microscopes.

Aspinwall’s team has monitored oxygen using the new sensor and is currently constructing a glucose sensor, which could help the treatment of diabetes.

Current biological sensors are made from hard plastic beads, coated in chemicals. But these can break down chemically, disrupt cellular processes, or become toxic. Also, they are incapable of detecting large molecules such as proteins.

By utilising organic compounds for his sensors, Aspinwall believes he has created sensors that are far more stable and sensitive. ‘We have been able to incorporate these types of materials, while also adding a previously unattainable level of chemical stability,’ he said.

Although long-term uses for the sensors will be the detection of biological toxins and chemical warfare agents in humans, experiments are currently confined to the laboratory.