A team of Japanese researchers has engineered biocompatible quantum nanosensors small enough to operate inside living cells, enabling precise temperature mapping and chemical detection at the organelle level — a potential breakthrough for cancer biology and medicine.
Scientists in Japan have built a new class of molecular quantum nanosensors capable of functioning directly inside living cells, measuring temperature with subcellular precision and detecting chemical signals linked to cellular stress. The findings, published April 29 in Science Advances, could reshape how researchers study the internal environments of cells — including cancer cells.
The sensors, called molecular quantum nanosensors (MoQNs), were developed by researchers at the National Institutes for Quantum Science and Technology (QST) and the University of Tokyo, in collaboration with Kyushu University. They are built from pentacene molecular spin qubits embedded in para-terphenyl nanocrystals and coated with a biocompatible surfactant, allowing them to enter cells without causing harm.
A New Approach to Intracellular Sensing
Understanding the physical and chemical conditions inside living cells — temperature gradients, oxidative stress, metabolic activity — has long been a central challenge in biology. Existing tools like nanodiamonds, quantum dots and fluorescent proteins have made inroads, but each comes with drawbacks: inconsistent particle-to-particle behavior, limited thermometric accuracy, or biocompatibility concerns.
MoQNs sidestep many of these problems. Unlike conventional solid-state quantum sensors that depend on atomic defects inside hard crystals, MoQNs introduce molecular qubits into host nanocrystals without creating vacancies. That design choice dramatically reduced variability between individual particles and improved the reliability of temperature readings from single sensors inside cells.
The research team first verified that cells containing MoQNs remained healthy over time — maintaining membrane integrity, metabolic function and normal cell-cycle progression. That biocompatibility check was essential before any biological measurements could be trusted.
Mapping Heat Inside Cancer Cell Nuclei
Once inside cells, the sensors demonstrated a range of quantum capabilities, including optically detected magnetic resonance (ODMR), Rabi oscillations and spin-echo measurements. To sharpen thermometric accuracy further, the team engineered a modified version called dMoQNs, substituting standard pentacene with a fully deuterated form to fine-tune electron-nuclear interactions at the molecular level.
Using dMoQNs, the researchers mapped absolute temperature at multiple locations within the cytoplasm of living cancer cells and found that intracellular temperatures were consistently higher than the surrounding medium — and that those differences varied by location within the cell. When the sensors were guided into cell nuclei, the team observed localized thermal variation within the nucleus itself, a level of spatial detail that has rarely been achieved before.
“This work shows that MoQNs can operate directly inside living cells while maintaining the precision needed for absolute thermometry,” Hitoshi Ishiwata, the team leader of the Quantum Bioengineering Team at QST and an associate professor at Chiba University, said in a news release. “We believe this opens a new route toward quantitative quantum measurement of intracellular environments.”
Detecting Radical Signals Tied to Cellular Stress
Temperature was not the only target. After treating cells with hydrogen peroxide to trigger radical-generating conditions — mimicking oxidative stress — the sensors detected changes in spin relaxation and coherence in both the cytoplasm and nucleus. This means MoQNs can also serve as probes for the redox environment inside cells, a property relevant to understanding cancer, aging and inflammation.
Why It Matters for Students and Researchers
For students in biology, chemistry, physics, or biomedical engineering, this work sits at a genuinely exciting intersection of fields. Quantum sensing — once largely confined to physics labs — is moving into living systems. The ability to non-invasively measure temperature and chemistry at the scale of individual organelles opens doors to understanding how cancer cells generate and manage heat differently from healthy tissue, how oxidative stress propagates through a cell, and ultimately how drugs or therapies alter those dynamics in real time.
The platform’s chemical tunability is also significant. Because the sensors are built from molecular components, researchers can adjust their properties — sensitivity range, target signals, surface chemistry — in ways that rigid crystal-based sensors cannot easily accommodate. That flexibility positions MoQNs as a generalizable toolkit rather than a single-purpose device.
Source: National Institutes for Quantum Science and Technology