Quantum Effect Generates Different View of Alzheimer’s

DOUGLAS FARMER, SENIOR EDITOR
doug.farmer@photonics.com

An exploration into quantum effects produced in nanoscale biological processes has the potential to upend traditional perceptions of the causes and effects of Alzheimer’s disease and other neurological conditions. Researchers have discovered that when tryptophan, an amino acid that is a fundamental building block of certain proteins, collects in a structural network within neural fibers, it can collect harmful ultraviolet light and release it at biologically safe intensities.

The scientists at the Quantum Biology Laboratory at Howard University have focused their recent investigation on increased quantum yields (the ratio of photons emitted to those absorbed) on cytoskeletal structures including microtubules and actin filaments, and amyloid fibrils of varying lengths — a concept called single-photon superradiance. They learned that when tryptophan is grouped in structures — such as in amyloid fibrils — they absorb high-energy photons at ultraviolet wavelengths, potentially dramatically reducing the phototoxicity caused by free radicals, or a buildup of unbound molecules produced during cellular metabolism. This buildup causes oxidative stress, which can lead to cell damage and harm to biological systems.

“The superradiant enhancement of the quantum yield in tryptophan networks in amyloid fibrils is dramatically increased relative to other bioarchitectures,” said Philip Kurian, principal investigator and founding director of the Quantum Biology Laboratory. “This is primarily due to two features: an extremely high density of tryptophan in fibrils leading to stronger electromagnetic coupling strengths, and their highly organized helical symmetry.”

Many attempts at treating Alzheimer’s — characterized by brain cell death and a loss of memory and neurological functioning — have focused on pharmaceuticals or other therapies that reduce or eliminate amyloid “tangles” that are often present in the brains of people with dementia, and have been largely unsuccessful. The researchers involved in the quantum study believe that such treatments are unsuccessful because these tangles could be the body’s way of compensating for the existence of the oxidative stress that can cause Alzheimer’s, but are not the root cause.

While much research in this area remains to be completed, Kurian said that he hopes neuroscientists and others shift their thinking about what causes Alzheimer’s disease and how it can be treated.

“I could envision a nanoparticulate delivery system of UV superabsorbers that would enhance the fibrils’ photoprotective effect, but this would only mitigate the oxidative stress in the cellular environment,” he said.

The implications of the research, the team noted, go beyond neurodegenerative disease; they could also lead to new breakthroughs in the understanding of neural communication and messaging. Superradiant effects can last hundreds of femtoseconds and could effectively function as pulses that expand computational capacity far beyond what was previously understood in the context of chemical signaling, Kurian said.

With support from the Alfred P. Sloan Foundation, the team will next be experimenting with such increases in computational capacity in an aneural eukaryotic organism, Physarum polycephalum, a slime mold and single-cell amoeba with an extensive network of cytoskeletal tubes that stream intracellular fluid through muscle-like contractions.

The research was published in Frontiers in Physics (www.doi.org/10.3389/fphy.2024.1387271).