Spit power: How energy from saliva can predict a woman’s ovulation

Scientists have discovered that spit can be used to power small electronic devices – although the future isn’t going to involve us having to spit on our gadgets when they’re low on power.

The tiny fuel cell collects energy and can power equally small devices, the creators from Penn State University, US, say.

Potential uses include being able to predict when women are going to ovulate, days before they start.

“By producing nearly 1 microwatt in power, this saliva-powered, micro-sized MFC already generates enough power to be directly used as an energy harvester in microelectronic applications,” the researchers report in a recent issue of Nature Publishing Group’s Asia Materials.


They don’t produce much energy but they can produce enough to run on-chip applications.

The scientists said that one use for the technology could be in a tiny ovulation predictor – which would be based on the conductivity of a woman’s saliva. The saliva in a woman’s mouth changes five days before ovulation.

The device would measure the conductivity of the saliva in the mouth while also using it as a power source and send the reading to a nearby mobile phone.

In theory the chip could be used to collect and report data on the health of those who use it. The researchers said the fuel cell can be powered with any liquid that has enough organic material, which opens the door for wider applications of the technology.

“There is a lot of organic stuff in saliva.”

The microbial fuel cells, which are made up of saliva input ports, an anode, cathode and a chamber, create energy when bacteria break down organic material. This produces a charge that is transferred to the anode in the device.

The researchers usually look to wastewater as a source for both the organic material and the bacteria to create either electricity or hydrogen. However theses latest cells work differently.

Bruce E. Logan from the University said: “There is a lot of organic stuff in saliva.”

He continued: “We have previously avoided using air cathodes in these systems to avoid oxygen contamination with closely spaced electrodes.”

“However, these micro cells operate at micron distances between the electrodes. We don’t fully understand why, but bottom line, they worked.”


Fighting cancer with nanotechnology: lasers, nanoballoons and nanoparticles

Blanket chemotherapy, the primary method for treating cancerous tumours, has long been seen as a very heavy-handed approach, but for many years nothing has matched it in terms of effectiveness.

But that could soon change. Today two entirely different approaching to fighting cancer were announced, which have two things in common. Firstly, they work using nanotechnology, and secondly, they are targeted solutions.

A targeted cancer treatment would be revolutionary for the field: no longer would the dreadful, exhausting side effects of conventional treatments have to be endured by already weak cancer patients. Instead tumours could be destroyed without risking damage to other parts of the body.


One cancer-busting approach uses magnetically controlled nanoparticles to make tumour cells self destruct.

Microscopic particles of iron oxide that have been magnetised using a special method are applied to the tumour cells. Once they are inside the cancerous cells, the iron nanoparticles are exposed to magnetic field.

Because they have been magnetised, this causes the particles to rotate, making them destroy the cancer cells.

This isn’t the first time magnetic nanoparticles have been tried to treat cancers, but it has the advantage over other approaches because previous attempts generated heat to damage the cancer. This had the unfortunate side effect of damaging surrounding healthy tissue, making it a risky treatment solution.

“The clever thing about the technique is that we can target selected cells without harming surrounding tissue. There are many ways to kill cells, but this method is contained and remote-controlled,” said Lund University professor Erik Renström.

An alternative solution still uses chemotherapeutic drugs, but in a way that makes the normal approach of whole body treatment seem like something out of the dark ages.

Instead concentrated doses of the medicine are encased in tiny nanoballoons, also known as PoP-liposomes, that are 1,000 times thinner than a human hair, and are made of an organic compound with a substance similar to vegetable oil.

Nanoballoons have a curious property that researchers are yet to fully understand: they open when hit by a red laser that is completely harmless to humans. As a result, the drug-filled balloons could be triggered to open in the affected area of the body, treating the cancer while minimising side effects.

“Think of it this way,” said study author and University at Buffalo biomedical engineering assistant professor Dr Jonathan Lovell. “The nanoballoon is a submarine. The drug is the cargo. We use a laser to open the submarine door which releases the drug. We close the door by turning the laser off. We then retrieve the submarine as it circulates through the bloodstream.”

Both technologies are a long way from being ready for public use.

The nanoparticles team says there is a lot of work to be done before clinical trials on the solution can even start, and Lovell believes that the nanoballoon system could start clinical trials within five years.

Nevertheless, we can only hope this is the start of a whole new approach to cancer treatment.