Molecular Quantum Nanosensors Functioning in Living Cells

Intracellular quantum sensing offers a powerful strategy for probing biophysical phenomena such as temperature distributions within living cells. However, current nanoscale quantum sensors—nanodiamonds with nitrogen-vacancy (NV) centers, quantum dots, and green fluorescent proteins (GFP)—are limited by material heterogeneity, cytotoxicity, and insufficient specificity for quantitative nanoscale thermometry. Here, we introduce molecular quantum nanosensors (MQNs) as a next-generation platform for intracellular quantum measurement of absolute temperature. By embedding pentacene molecular qubits into para-terphenyl nanocrystals and coating them with the biocompatible surfactant Pluronic F127, we construct a coherent spin system with molecular-level uniformity and long spin coherence times under physiological conditions. These sensors enable organelle-selective detection of local temperature changes in living cells via optically detected magnetic resonance (ODMR). We perform coherent spin manipulations—including Rabi oscillations, spin echo, and T₁ relaxometry—directly within the nuclear environment, establishing robust coherence measurement in live-cell conditions. Furthermore, by chemically suppressing hyperfine interactions of pentacene qubits, we achieve spatially resolved absolute temperature sensing inside the nucleus with thermometric precision defined by intrinsic spin energy levels. MQNs thus provide a chemically tunable and biologically compatible platform for precision quantum sensing of thermal and biochemical states inside living systems.