A revolutionary jab that could repair spinal cord injuries has been developed by scientists.
Paralysed mice regained the ability to walk within just four weeks - after a single injection.
The drug was so effective human trials could begin next year. The drug encourages nerves to regrow.
Study leader Professor Samuel Stupp, of Northwestern University, Illinois, said: "Our research aims to find a therapy that can prevent individuals from becoming paralysed after major trauma or disease.
"For decades, this has remained a major challenge for scientists because our body's central nervous system, which includes the brain and spinal cord, does not have any significant capacity to repair itself after injury or after the onset of a degenerative disease.
"We are going straight to the FDA (Food and Drug Administration) to start the process of getting this new therapy approved for use in patients, who currently have very few treatment options."
The technique also worked on human cells grown in lab dishes. It could help stroke victims make a full recovery.
It could even cure illnesses that affect the central nervous system - including Alzheimer's, Parkinson's and motor neurone disease.
Damage to the spinal cord interrupts the constant stream of electrical signals from the brain to the body. It can lead to paralysis below an injury.
The medication sends bioactive signals to trigger cells to regenerate - leading to five key improvements.
Long spindly parts of the severed nerves - called axons - mended and scar tissue which prevents healing disappeared.
Myelin, an insulating tissue, reformed around cells, functional blood vessels delivered nutrients to the injury and motor neurons survived.
The study in the journal Science found the drug biodegrades and nourishes the cells after three months - being absorbed without side effects.
Superman star Christopher Reeve broke his neck in 1995 when he was thrown from his horse during an equestrian competition in Virginia.
He was left quadriplegic and died nine years later - at the age of 52. Life expectancy after spinal cord injury has not improved since the 1980s.
In the UK an estimated 50,000 people are living with a spinal cord injury. Each year approximately 2,500 people are newly injured.
It affects nearly 300,000 in the US. Life for these patients can be extraordinarily difficult.
Fewer than three percent ever recover basic physical functions. A third are re-hospitalised at least once a year.
Prof Stupp, an expert in regenerative medicine, said: "Currently, there are no therapeutics that trigger spinal cord regeneration.
"I wanted to make a difference on the outcomes of spinal cord injury and to tackle this problem, given the tremendous impact it could have on the lives of patients.
"Also, new science to address spinal cord injury could have impact on strategies for neurodegenerative diseases and stroke."
Injected as a liquid, the drug immediately gels into a complex network of nanofibers that mimic the extracellular matrix of the spinal cord.
The cocktail of synthetic materials are then able to communicate with cells.
Prof Stupp explained: "Receptors in neurons and other cells constantly move around.
"The key innovation in our research, which has never been done before, is to control the collective motion of more than 100,000 molecules within our nanofibres.
"By making the molecules move, ‘dance’ or even leap temporarily out of these structures, known as supramolecular polymers, they are able to connect more effectively with receptors."
The researchers found fine-tuning their motion to make them more agile resulted in greater therapeutic efficacy in paralysed mice.
They also performed better during tests with human cells - indicating increased bioactivity and cellular signaling.
Prof Stupp said: "Given that cells themselves and their receptors are in constant motion, you can imagine that molecules moving more rapidly would encounter these receptors more often.
"If the molecules are sluggish and not as 'social,' they may never come into contact with the cells."
Once connected to the receptors, they trigger two cascading signals, both of which are critical to spinal cord repair.
One boosts the axons. They have been likened to electrical cables - increasing communication between the body and brain.
The second saves neurons by causing the proliferation of cells and promoting the regrowth of lost blood vessels and tissue.
The therapy also induces myelin to rebuild and reduces scarring that prevents healing.
It could be used to prevent paralysis after road crashes, falls, sports accidents and gunshot wounds - or from diseases.
But Prof Stupp believes the underlying discovery - that "supramolecular motion" is a key factor in bioactivity - can be applied to other targets.
He added: "The central nervous system tissues we have successfully regenerated in the injured spinal cord are similar to those in the brain affected by stroke and neurodegenerative diseases, such as motor neurone disease, Parkinson's and Alzheimer's.
"Beyond that, our fundamental discovery about controlling the motion of molecular assemblies to enhance cell signaling could be applied universally across biomedical targets."