Biosensing Machine That Can Smell and Differentiate Odors Developed

Researchers from The University of Manchester and the University of Bari have developed a biosensor that can differentiate smells that are similar to each other. The machine can distinguish the smell of two similar objects such as spearmint or caraway.

The scientists have found a way to manufacture odorant binding proteins in quantities that can be used in the biosensor. Odorant binding proteins helps the nose perceive the different smells by reacting to the different type of chemicals around

The biosensor incorporate the proteins using a transistor. By doing so, the team were able to detect and measure the changes in current as the proteins reacted to odors. The system is incredibly sensitive with a detection limit that approaches that of the human nose.

The findings are published in the journal Nature Communications.

Long Term Implantable Bio-Sensors Developed Using Carbon Nanotubes

Using carbon nanotubes, scientists have developed a biosensor that can be implanted under the skin that will last more than a year. They have also developed a short term biosensor that can travel through the blood stream flowing through the different organs of the body without causing damage.

In order to get a reading and collect data from the sensors, a laser that produces near-infrared light is used to detect the fluorescent signal off of the nanotube based devices.

The long term biosensor was made to detect nitric oxide (NO) levels in the body for monitoring cancerous cells. This is the first time that implantable nanosensors could be used within the body for this extended period of time.

For the biosensor to last under the skin, it is embedded in a gel made from a polymer called alginate for protection.

This application is not limited to NO detection, it can also be used to detect glucose (blood sugar) levels in the body for monitoring diabetes.

Research Identifies 10 Basic Categories of Odor

Researchers have classified 10 basic categories of odor. These categories describe the fundamental descriptors for the sense of smell. The categories are fragrant, woody/resinous, fruity (non-citrus), chemical, minty/peppermint, sweet, popcorn, lemon and two kinds of sickening odors: pungent and decayed.

The sense of smell (olfaction) utilizes sensory cells of the nasal cavity. Odor molecules bind to specific sites on the olfactory receptors which sends the signal to the brain for processing. These signals are then interpreted by the brain into the odor categories described above. Just like with the sense of taste, these descriptors can be combined to form complex odors.

Properties of the perceptual basis set W. (A) Plot of normalized odor descriptor amplitude vs. odor descriptor number for the basis vector W1. Each point along the x-axis corresponds to a single odor descriptor, and the amplitude of each descriptor indicates the descriptor's relevance to the shown perceptual basis vector. Colored circles show the seven largest points in the basis vector, and descriptors corresponding to these points are listed to the right. (B) Waterfall plot of the 10 basis vectors constituting W, used in subsequent analyses. Note that each vector contains many values close to or equal to zero.
Credit: Castro JB, Ramanathan A, Chennubhotla CS (2013) Categorical Dimensions of Human Odor Descriptor Space Revealed by Non-Negative Matrix Factorization. PLoS ONE 8(9): e73289. doi:10.1371/journal.pone.0073289

Using Thermoacoustics To Develop Self-Powered Nuclear Reactor Backup Sensors

A thermoacoustic device uses sound waves to move heat from one place to another or use heat to create sound waves. Using this principle, a thermoacoustic engine uses either the heat transfer or the sound waves to produce electricity, cooling, or heat pumping.


Currently, researchers are looking into electricity created from pressure (piezoelectricity), refrigeration, and cryogenic applications.


Another category thermoacoustics can be of use, is in the development of sensors, particularly backup sensors for nuclear reactors. The Fukushima nuclear disaster is a prime example of this.


In the Fukushima incident, the power connections failed cutting off electricity to the backups, pumps, and sensor systems shutting them down. The reactors overheated due to the high radioactive decay heat and the nuclear plant's operators could not monitor the fuel rods in the reactor and spent fuel in the storage ponds.