Nanomushroom Biosensors Can Detect Single Molecules

The slide is made of a ‘nanoplasmonic’ material — its surface is coated in millions of gold nanostructures, each just a few billionths of a square meter in size. Plasmonic materials absorb and scatter light in interesting ways, giving them unique sensing properties. Nanoplasmonic materials have attracted the attention of biologists, chemists, physicists and material scientists, with possible uses in a diverse array of fields, such as biosensing, data storage, light generation and solar cells.

Nanomushroom biosensors.

Credit: OIST 

In several recent papers, Prof. Shen and colleagues at the Micro/Bio/Nanofluidics Unit at the Okinawa Institute of Science and Technology (OIST), described their creation of a new biosensing material that can be used to monitor processes in living cells.

“One of the major goals of nanoplasmonics is to search for better ways to monitor processes in living cells in real time,” says Prof. Shen. Capturing such information can reveal clues about cell behavior, but creating nanomaterials on which cells can survive for long periods of time yet don’t interfere with the cellular processes being measured is a challenge, she explains.

Counting Dividing Cells

One of the team’s new biosensors is made from a nanoplasmonic material that is able to accommodate a large number of cells on a single substrate and to monitor cell proliferation, a fundamental process involving cell growth and division, in real time. Seeing this process in action can reveal important insights into the health and functions of cells and tissues.

Researchers in OIST’s Micro/Bio/Nanofluidics Unit described the sensor in a study recently published in the journal Advanced Biosystems.

The most attractive feature of the material is that it allows cells to survive over long time periods. “Usually, when you put live cells on a nanomaterial, that material is toxic and it kills the cells,” says Dr. Nikhil Bhalla, a postdoctoral researcher at OIST and first author of the paper. “However, using our material, cells survived for over seven days.” The nanoplasmonic material is also highly sensitive: It can detect an increase in cells as small as 16 in 1000 cells.

The material looks just like an ordinary pieces of glass. However, the surface is coated in tiny nanoplasmonic mushroom-like structures, known as nanomushrooms, with stems of silicon dioxide and caps of gold. Together, these form a biosensor capable of detecting interactions at the molecular level.

Using their innovative printing technique, the Micro/Bio/Nanofluidics Unit at OIST has developed a nanoplasmonic material containing millions of mushroom-like structures covered with a uniform layer of biomolecules.

Credit: OIST