Science

Shape-memory implant could keep immobilized muscles from wasting away

When a limb is rendered motionless for lengthy durations of time, its muscles will inevitably start to atrophy. A brand new implant could assist keep that from occurring, nevertheless, by mechanically stretching and compressing these muscles.

Developed by scientists at Harvard University, the experimental machine is called MAGENTA, which stands for “mechanically active gel-elastomer-nitinol tissue adhesive.”

Running lengthwise by way of the implant is a spring made from nitinol. The latter is a shape-memory alloy that can quickly keep at one size after being mechanically stretched to that size, however then return to its default shorter size upon being heated to a sure temperature.

The spring is encased inside an oblong elastomer matrix that gives thermal insulation, and which stretches the spring out when it is not heated. A biocompatible adhesive on the elastomer permits it to stay to underlying muscle tissue.

The thought is that when a affected person’s arm or leg turns into immobilized – both by way of harm or a illness reminiscent of a number of sclerosis – a MAGENTA will get surgically implanted on a goal muscle throughout the limb.

A separate (however hardwire-connected) microprocessor/battery implant subsequently delivers {an electrical} present to the MAGENTA frequently, heating the nitinol spring and inflicting it to contract. As it does so, the muscle (and elastomer) get contracted together with it. When the present is shut off once more, the elastomer stretches the spring – and the muscle – again out.

In lab exams, mice had a tiny model of the machine implanted on the calf muscle of 1 hind leg, after which that leg was immobilized in a cast-like equipment for as much as two weeks. The outcomes of the experiments had been promising.

“While untreated muscles and muscles treated with the device but not stimulated significantly wasted away during this period, the actively stimulated muscles showed reduced muscle wasting,” stated Dr. Sungmin Nam, first creator of a paper on the analysis. “Our approach could also promote the recovery of muscle mass that already had been lost over a three-week period of immobilization, and induce the activation of the major biochemical mechanotransduction pathways known to elicit protein synthesis and muscle growth.”

It was moreover discovered that as an alternative of getting to be hardwired to an influence supply, the MAGENTA could be wirelessly activated by shining laser mild onto it by way of the overlying pores and skin. Taking this method at the moment is not as efficient as heating the spring through {an electrical} present, however it’s hoped that this will likely change as soon as the technology is additional developed.

“While the study provides first proof-of-concept that externally provided stretching and contraction movements can prevent atrophy in an animal model, we think that the device’s core design can be broadly adapted to various disease settings where atrophy is a major issue,” stated senior creator Dr. David Mooney.

The paper was not too long ago printed within the journal Nature Materials.

Source: Wyss Institute for Biologically Inspired Engineering at Harvard University

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