‘Micro-swimmers’ may soon help with drug delivery

‘Micro-swimmers’ may soon help with drug delivery

Subject: Science & Tech

Section: Msc

Context- it is possible to use light as a fuel to move microbots in real ­body conditions with intelligent drug ­delivery that is selectively sensitive to can­cer cells.

Concept-

Microbots:

• Made from the two ­di­mensional compound poly (heptazine imide) carbon ni­tride (aka PHI carbon ni­tride), these microbots are nothing like the miniaturized humans.
• They range from 1­- 10 micrometre (a micro­ metre is one millionth of a metre) in size, and can self­ propel when energised by shining light.

How they swim

• The PHI carbon nitride mi­croparticles are photocata­lytic.
• Like in a solar cell, the incident light is converted in­ to electrons and holes.
• These charges drive reactions in the surrounding liquid. This reaction, combined with the particle’s electric field, makes the microbots (micro­ swimmers) swim.
• As long as there is light, electrons and holes are pro­duced on the surface of the swimmers, which in turn react to form ions and an electric field around the swimmer. These ions move around the particle and cause fluid to flow around the particle. So this fluid flow causes the micro­swimmers to move.
• Just like the fragrance of incense wafts from a region of high concentration to low, the ions move from the bright surface of the micro­ swimmer to the rear end.
• The particles are nearly spherical, and the incident light illuminates one ­half of the sphere, leaving the other dark. As photocatalysis is light ­driven, it occurs only on the brightened hemisph­ere. As the ions move from the bright side to the dark side, micro­swimmers march towards the direction of the light source.

Drug delivery

• The re­searchers found that Doxo­ rubicin, a drug used to treat cancer, was readily ab­sorbed.
• By changing the pH of the solution or by trigger­ing it with light, the research­ers showed the drug release could be activated.