Lasers Could Cut Lifespan of Nuclear Waste from a Million Years to 30 Minutes

Whatever one thinks of nuclear energy, the process results in tons of radioactive, toxic waste no one quite knows what to do with. As a result, it’s tucked away as safely as possible in underground storage areas where it’s meant to remain a long, long time: The worst of it, uranium 235 and plutonium 239, have a half life of 24,000 years. That’s the reason eyebrows were raised in Europe — where more countries depend on nuclear energy than anywhere else — when physicist Gérard Mourou mentioned in his wide-ranging Nobel acceptance speech that lasers could cut the lifespan of nuclear waste from “a million years to 30 minutes,” as he put it in a followup interview with The Conversation.
Who is Gérard Mourou? Mourou was the co-recipient of his Nobel with Donna Strickland for their development of Chirped Pulse Amplification (CPA) at the University of Rochester. In his speech, he referred to his “passion for extreme light.”

CPA produces high-intensity, super-short optical pulses that pack a tremendous amount of power. Mourou’s and Strickland’s goal was to develop a means of making highly accurate cuts useful in medical and industrial settings. It turns out CPA has another benefit, too, that’s just as important. Its attosecond pulses are so quick that they shine a light on otherwise non-observable, ultra-fast events such as those inside individual atoms and in chemical reactions. This capability is what Mourou hopes give CPA a chance of neutralizing nuclear waste, and he’s actively working out a way to make this happen in conjunction with Toshiki Tajima of UC Irvine.

“Take the nucleus of an atom. It is made up of protons and neutrons. If we add or take away a neutron, it changes absolutely everything. It is no longer the same atom, and its properties will completely change. The lifespan of nuclear waste is fundamentally changed, and we could cut this from a million years to 30 minutes!,”  explains Mourou.

We are already able to irradiate large quantities of material in one go with a high-power laser, so the technique is perfectly applicable and, in theory, nothing prevents us from scaling it up to an industrial level. This is the project that I am launching in partnership with the Alternative Energies and Atomic Energy Commission, or CEA, in France. We think that in 10 or 15 years’ time we will have something we can demonstrate. This is what really allows me to dream, thinking of all the future applications of our invention.”

While 15 years may seem a long time, when you’re dealing with the half-life of nuclear waste, it’s a blink of an eye.


How to Bioprint Muscles

Researchers at Harvard Medical School and Sichuan University have developed a novel means of 3D bioprinting live human muscle-tendon tissues. As opposed to normal extrusion bioprinting, which involves depositing cells along X and Y axes, the team’s ‘cryo-bioprinting’ process sees them frozen and stacked vertically, in a way that allows for the creation of freestanding, mixed-cell tissues. According to the scientists, their technique also yields tissues that are more robust and versatile than those produced via conventional bioprinting, particularly when it comes to those anisotropic in nature, thus they say it could now find regenerative medicine, drug discovery, or personalized therapeutic applications.

To overcome the tissue-stacking issues, the researchers have turned to ‘ice-templating,’ a freezing process that causes microchannels to form within cell-laden hydrogel-based structures once they thaw. Naturally, doing so would ordinarily damage the viability of such cells, so to prevent this, the team loaded theirs with the cryoprotective agents (CPAs) melezitose and dimethyl sulfoxide.

Once frozen, the researchers then used ultraviolet (UV) light to vertically cross-link this novel bio-ink, and extrude it into tissues composed of high-resolution, honeycomb-like microchannel networks, capable of supporting various different types of cell, whether they be skeletal muscle myoblasts or human umbilical vein endothelial cells.

Our results indicate that [our] bio-ink, consisting of gelatin methacryloyl and CPAs, could be effectively used in vertical 3D cryo-bioprinting to enable cell encapsulation at high viability,” explained the team in their paper. “With the help of the interconnected, anisotropic, gradient microchannels formed by directional freezing during the process, the desired cellular alignments were also realized.

Given that 3D bioprinting is an emerging technology, it’s hardly surprising that its format is continually subject to change, with researchers constantly bringing innovative new ideas to the field. Just last month, scientists at the UK’s University of Birmingham and University of Huddersfield, revealed that they had developed a novel skin 3D bioprinting technique that enables the treatment of chronic wounds.

Elsewhere, on a more commercial level, Inventia Life Science raised $25 million towards the development of its RASTRUM 3D bioprinting technology in December 2021. In effect, the firm’s approach is designed to enable the layering of cell-loaded droplets onto one another at pace, in a way that allows them to join on contact and doesn’t affect their overall viability.

Looking even further back, researchers at Imperial College London have also experimented with cell-freezing as a means of bioprinting viable human implants.