How tiny particles can tackle big diseases

Nanotechnology is most often celebrated for its potential to diagnose and treat human disease. University of Toronto chemist Bernie Kraatz‘s research is focused on fine-tuning this potential.

Bernie Kraatz (Ken Jones, University of Toronto Scarborough)

Bernie Kraatz (Ken Jones, University of Toronto Scarborough)

Kraatz makes nano-sized “hooks” designed to fish out from blood, serum or urine the molecules that signal diseases such as cancer or HIV. The hooks are made of combinations of nanoparticles that can also lock on to the biochemical changes that happen in our bodies when drugs fight these illnesses. This means they can both diagnose disease and monitor treatment.

While Kraatz’s nanoparticle hooks are still in the testing stage, he has designed them to be embedded in microchips used in hand-held biosensors. These biosensors could one day be used in the field and the hospital to quickly scan biological samples for disease while making sure drugs are working as they should. It is, as Kraatz says, a step toward more personalized medicine.

Such biosensors could also help border agents quickly detect DNA indicating the presence of endangered or invasive species in goods. Water treatment workers could test for pathogens such as viruses or bacteria. Right now, testing for pathogens means culturing samples, which can take several days. “We are offering continuous and fast detection,” says Kraatz.

Building instructions

Kraatz’s nano-sized hooks are made of tiny chemical compounds that mimic larger, disease-signalling biological molecules. “The compounds I make are small compared to the biomolecules we are fishing for, but they retain the ability to bind with them,” he says.

Getting these hooks just right requires an intimate understanding of the chemical properties of both the compounds and the biomolecules in our bodies that he wants to identify. Kraatz makes his hooks with nanoparticles of ferrocene. Ferrocene is a crystalline compound composed of iron, carbon and hydrogen. This compound is responsible for first-level sensing and can provide biosensors with a simple read-out.

But ferrocene needs help recognizing exactly what it has found. And so Kraatz enlists the help of other nanomaterials — fragments of DNA and/or fragments of peptides, which are short chains of amino acids.

The DNA fragments recognize and bind with larger mutant, disease-causing DNA. Meanwhile, the peptide fragments recognize and bind with larger mutant proteins that signal the disease’s progress.

The final step in this complicated process involves attaching the ferrocene/DNA/peptide compound to a silicon chip coated in a thin layer of gold nanoparticles. This last piece of nanotechnology, the nanogold coating, conducts electricity in the biosensor’s digital reader, which health workers can then consult for results.

 

A version of this story was originally published by University of Toronto’s Edge magazine.  It has been edited for clarity, accuracy and brevity, and is republished here with permission

Tagged: Environment & Sustainability, Health & Wellbeing, Jobs & the Economy, Natural Resources, Technology, Blog, Stories

Share: Print

Leave Comments

Questions

Questions

Researchers

Blog Posts