New research in the journal Nature Aging takes a page from the field of renewable energy and shows that genetically engineered mitochondria can convert light energy into chemical energy that cells can use, ultimately extending the life of the roundworm C. elegans.  While the prospect of sunlight-charged cells in humans is more science fiction than science, the findings shed light on important mechanisms in the aging process.

Caenorhabditis elegans (C. elegans) has been the source of major discoveries in molecular and cell biology

“We know that mitochondrial dysfunction is a consequence of aging,” said Andrew Wojtovich, Ph.D., associate professor of Pharmacology & Physiology at the University of Rochester Medical Center and senior author of the study.  “This study found that simply boosting metabolism using light-powered mitochondria gave laboratory worms longer, healthier lives.  These findings and new research tools will enable us to further study mitochondria and identify new ways to treat age-related diseases and age healthier.”

Mitochondria are organelles found in most cells in the body.  Often referred to as cellular power plants, mitochondria use glucose to produce adenosine triphosphate (ATP), the compound that provides energy for key functions in the cell, such as muscle contraction and the electrical impulses that help nerve cells communicate with each other.

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Scientists have developed a photoelectrode that can harvest 85 percent of visible light in a 30 nanometers-thin semiconductor layer between gold layers, converting light energy 11 times more efficiently than previous methods. In the pursuit of realizing a sustainable society, there is an ever-increasing demand to develop revolutionary solar cells or artificial photosynthesis systems that utilize visible light energy from the sun while using as few materials as possible. The research team, led by Professor Hiroaki Misawa of the Research Institute for Electronic Science at Hokkaido University (Japan), has been aiming to develop a photoelectrode that can harvest visible light across a wide spectral range by using gold nanoparticles loaded on a semiconductor. But merely applying a layer of gold nanoparticles did not lead to a sufficient amount of light absorption, because they took in light with only a narrow spectral range.

In the study published in Nature Nanotechnology, the research team sandwiched a semiconductor, a 30-nanometer titanium dioxide thin-film, between a 100-nanometer gold film and gold nanoparticles to enhance light absorption. When the system is irradiated by light from the gold nanoparticle side, the gold film worked as a mirror, trapping the light in a cavity between two gold layers and helping the nanoparticles absorb more light. To their surprise, more than 85 percent of all visible light was harvested by the photoelectrode, which was far more efficient than previous methods. Gold nanoparticles are known to exhibit a phenomenon called localized plasmon resonance which absorbs a certain wavelength of light.

“Our photoelectrode successfully created a new condition in which plasmon and visible light trapped in the titanium oxide layer strongly interact, allowing light with a broad range of wavelengths to be absorbed by gold nanoparticles,” says Hiroaki Misawa.

 Source: https://www.global.hokudai.ac.jp/