New Needle Detects Muscle Resistance for Accurate Injections

A new needle will help deliver medication with more precision.
Jessica Miley

A new needle can detect changes in a receivers resistance in order to find a safe passage that can safely deliver medication in preclinical testing.

The high tech device was created by Investigators from Brigham and Women's Hospital in the US. Syringes and other hollow needles have been used to deliver medicines to patients for over a century; however, they are really only as good as their operator. 


Using needles to deliver medication to delicate regions such as the suprachoroidal space at the back of the eye can be very challenging even for experienced practitioners.

"Targeting specific tissues using a conventional needle can be difficult and often requires a highly trained individual," said senior corresponding author Jeff Karp, Ph.D., Professor of Medicine at the Brigham. 

"In the past century there has been minimal innovation to the needle itself, and we saw this as an opportunity to develop better, more accurate devices. We sought to achieve improved tissue targeting while keeping the design as simple as possible for ease of use." 

New needle knows where to go

One place the new needle technology will be most useful in delivering medication to the suprachoroidal space (SCS), which is located between the sclera and choroid in the back of the eye. 


This is an important location for medication delivery but getting drugs there is very challenging as it requires the needle to stop after transitioning through the sclera, which is less than 1 millimeter thick to avoid damaging the retina. 

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Other difficult places for needles to inject include the epidural space around the spinal cord (used for epidural anesthesia to ease pain during labor), the peritoneal space in the abdomen, and subcutaneous tissue between the skin and muscles. The new device, called the i2T2 was produced using a standard hypodermic needle and parts from commercially available syringes. 

Tested on both animals and extracted tissues

The needles intelligent injector uses the differences in people's body tissues densities to enable needle movement into a target tissue area. The feedback is instantaneous which allows for better tissue targeting and reduce overshoot. 

The i2T2 was tested on three animal models to determine the accuracy of injections in the suprachoroidal, epidural and peritoneal spaces as well as subcutaneously. 

In tests on both extracted tissue and animal model, it was shown that i2T2 prevented overshoot injuries and precisely delivered medication to the desired location without additional precision training. 

"The stem cells injected into the SCS survived, indicating that the force of injection and the transit through the SCS were gentle on the cells," said Kisuk Yang, a co-author and postdoctoral fellow in Karp's laboratory. 

"This should open the door to regenerative therapies for patients suffering from conditions of the eye and beyond."

"This intelligent injector is a simple solution that could be rapidly advanced to patients to help increase target tissue precision and decrease overshoot injuries. We have completely transformed needles with a small modification that achieves better tissue targeting," said first author Girish Chitnis, Ph.D., a former postdoctoral fellow in Karp's laboratory. 

"This is a platform technology, so the uses could be very widespread." The results of the testing and development are published in Nature Biomedical Engineering.

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