A hi-tech gel could be used instead of major surgery to treat chronic lower back pain, according to a study.
Chronic back pain can cause misery to sufferers
The gel contains tiny particles which swell and stiffen when injected into a damaged area.
Tests on animals, reported in the journal Soft Matter, showed it was able to repair the discs that provide a cushion between the bones of the spine.
The University of Manchester work raises the possibility of patients being able to regain full mobility.
It offers a potential alternative to spinal fusion surgery, a technique in which the bones of the spine - the vertebrae - are fused together to reduce pain by eliminating motion in the affected area.
This is a major procedure, which requires considerable recovery time and can lead to a significant loss of mobility.
Degeneration of the intervertebral discs causes holes in the load-bearing tissue of the disc.
This decreases the height of the disc, reducing its ability to insulate the vertebrae, and resulting in pain.
The micro gel particles the research team have developed are like "smart sponges" when dispersed in water.
The material is a fluid with a low pH - indicating a high level of acidity - and can be injected through a syringe.
However, at the higher pH found in the body it changes to a stiff gel because of the absorption of water.
In tests, the researchers injected the gel into a damaged disc taken from a pig, and increased pH to levels similar to those found in the body by injecting alkaline solution.
Researcher Professor Tony Freemont said there was a pressing need to develop a non-surgical method for repairing intervertebral discs.
He said: "Our approach has the advantage of restoring spinal mobility whereas spinal fusion surgery results in a significant loss of mobility at the fused and adjacent discs."
However, his colleague Dr Brian Saunders said: "Although we are encouraged by our findings, much work lies ahead to develop a viable non-surgical repair technology to replace spinal fusion as the standard surgical treatment for chronic lower back pain."
The Manchester team plan to investigate the development of biodegradable micro gels that can release additives to stimulate regeneration of intervertebral disc tissue.
Dr Alison McGregor, an expert in back pain at Imperial College London, described the research as "very exciting".
However, she said: "Managing the back pain of people with degenerate discs often goes beyond damage to the disc itself and leads to many problems in the surrounding tissues, especially muscles and ligaments.
"I am not sure that restoring some of the properties to the disc will lead to normal motion and normal function.
"Often there are many psychosocial factors and other factors that are contributing to the pain and disability that these people present with."
Dr Joan Hester, president of the British Pain Society, agreed the gel would not work for all back pain sufferers.
"Pain can come from the tiny nerves that run round the edge of the disc, from ligaments, facet joints, inflamed nerve roots, from bone and from muscle spasm.
"Improving mechanical function of the disc and increasing mobility must have a beneficial effect, but will not provide a cure for all back pain.
"Injecting material into an intervertebral disc carries a small risk of introducing infection."
The research was funded by the Engineering and Physical Sciences Research Council.