Taking the pain out of injections

IISc. researchers have designed a capsule loaded with medicine that is triggered by micro-shock waves

Scientists at the Indian Institute of Science have successfully tested an alternative to syringes for drug delivery.

The method, tested on mice, delivers medicine through tiny capsules when triggered by a micro-shock wave.

Developing methods for alternative delivery of drugs has gained importance considering the large number of infections that are spread through contaminated, non-sterilised syringes. “Each year, 1.3 million early deaths are caused by unsafe injections,” said Dipshikha Chakravortty, a biologist on the team of aerospace engineers and cell biologists who developed the model. Their research was published in the journal The Royal Society of Chemistry last month.

The researchers designed tiny biocapsules made of a polymer (spermidine-dextran sulfate or Sper–DS). The capsules are so small that 10 of the biggest ones could be placed in a length of one millimetre. The capsules are loaded with either insulin or the antibiotic ciprofloxacin. They are then placed on the infection site — for instance, external diabetic wounds — and are triggered by micro-shock waves produced by a handheld machine.

“The micro-shock waves we create last a millionth of a second, and affect a small area. They don’t affect living cells in the body,” said Jagadeesh Gopalan, Professor, Department of Aerospace Engineering, IISc.

The result, say the researchers, is that a controlled portion of the drug is released with every shock wave (on an average 20 per cent of the medicine is released with every wave). Almost 90 per cent of the drug release was observed when the particles were exposed to micro-shock waves five times. “It can be used where there is a need for frequent injections (diabetes, for instance). This method can help do away with invasive procedures,” Ms. Chakravortty said.

Added benefit

The shock waves have an added benefit, the researchers noted. Infections by bacteria such as Staphylococcus (cause of foot infections that people living with diabetes are susceptible to) are lethal as they form a biofilm around the protein in the cell. The shock waves tear this biofilm and aid the treatment, scientists said.

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