Scientists find way to make cheap fluorescent nanodiamonds

London, Apr 30 : Diamond chips make for effective tools when it comes to delivering chemotherapy drugs. The only problem however, was that they were too expensive for regular use. Now, Taiwanese scientists have found a way to slash the cost of making these diamond chips by around 100 times.

The scientists have found a cheaper way to develop tiny fragments of flawed diamond called fluorescent nanodiamonds (FNDs), paving the way for them to be used to track the movement of cells around the body and for delivering genes.

FNDs have a similar size as that of the smallest viruses, and when they are hit with laser, they can continue to fluoresce for hours.

This is due to the defects in the diamond that absorb the laser energy and emit light of their own at a different wavelength. In fact, as diamond is stable and non-toxic, it turns out to be one of the sought after materials for use inside the body.

An earlier study in 2005 demonstrated that fluorescent properties of nanodiamond can be put to use for following cells moving through the body and another study last year showed that they could safely deliver chemotherapy drugs.

While cheaper alternatives to nanodiamonds, such as fluorescent dyes or small chunks of semiconductor known as quantum dots, are already in use, but the diamonds do not blink on and off like fluorescent dyes and are non-toxic unlike quantum dots.

More often than not, FNDs are made by firing a high-energy electron beam into commercially available diamond powder and then heating it up to 800C.

But, Huan-Cheng Chang and colleagues at Academia Sinica in Taipei made use of a much less intense, and hence cheaper, beam of helium ions to shoot at diamond powder to make FNDs of the same quality.

"The beam of helium ions knocks some carbon atoms out of the nanodiamonds, leaving vacancies behind," New Scientist quoted Chang, as explaining.

The vacancies combine with nitrogen atoms and create the flaws allowing the diamonds to absorb and re-emit laser light. Even the cheaper FNDs fluoresce almost like those produced with an electron beam.

While testing, Chang's team could easily track the movement of a single fluorescent nanodiamond within a cell for over 3 minutes.

The cheap diamonds may be used to monitor stem cells in developing tissue, or to carry drugs into cells and they can also be used for gene therapy, or DNA vaccines.

"In particular, we have demonstrated that FNDs are able to interact with plasmid DNA and to deliver different genes into cultured human cells," said Chang.

He also added that the cheaper diamond chips need to be made smaller for utilising them effectively as markers to reveal the inner workings of cells.

ANI