Quantum sensing is driving the chemical and biological measurements into a new era. This paper systematically introduces the underlying logic and representative systems of quantum chemical measurements. Quantum chemical measurement employs the superposition or entanglement of quantum systems—such as electrons，photons，atoms，and molecules—as probes. These probes are initialized，manipulated，and read out via optical and microwave techniques，enabling the transduction of physical-field signals generated by chemical and biological systems into precisely decodable quantum signals，and thereby allowing in situ，real-time，and high-precision measurement and imaging. This interdisciplinary direction achieves a deep integration of quantum physics，analytical chemistry，and biological physics，signifying a profound transformation of chemical metrology from classical measurements to quantum sensing.
Quantum sensing is driving the chemical and biological measurements into a new era. This paper systematically introduces the underlying logic and representative systems of quantum chemical measurements. Quantum chemical measurement employs the superposition or entanglement of quantum systems—such as electrons，photons，atoms，and molecules—as probes. These probes are initialized，manipulated，and read out via optical and microwave techniques，enabling the transduction of physical-field signals generated by chemical and biological systems into precisely decodable quantum signals，and thereby allowing in situ，real-time，and high-precision measurement and imaging. This interdisciplinary direction achieves a deep integration of quantum physics，analytical chemistry，and biological physics，signifying a profound transformation of chemical metrology from classical measurements to quantum sensing.
Background: High-precision sensing is vital for modern technology, yet conventional sensors are fundamentally constrained by classical noise limits. Quantum sensing leverages principles of quantum mechanics, such as superposition and entanglement, to overcome these barriers, offering unprecedented sensitivity. This review comprehensively analyzes the current state of quantum sensor technology, focusing on its underlying physical principles, emerging applications, and the pathway toward industrial maturation.Methods: We synthesize findings from key research areas, detailing the foundational quantum systems like Nitrogen-Vacancy (NV) centers in diamond and advanced optical techniques. The paper reviews the theoretical methods used to achieve sub-shot-noise performance and discusses the system-level engineering challenges necessary for practical deployment, particularly concerning microwave control and optical readout. We also assess the current landscape of standardization efforts for quantum technologies.Results: Significant breakthroughs are highlighted in both biomedical and environmental sensing. Applications range from tracking cellular redox-status using electron-paramagnetic resonance to ultra-sensitive salinity measurements. The analysis confirms that quantum sensing provides superior resolution compared to classical counterparts, unlocking new capabilities in in-vivo and real-time monitoring.Discussion: While offering transformative potential, widespread adoption faces hurdles, including the maintenance of quantum coherence in ambient environments and the high cost and complexity of current instrumentation. Future efforts must focus on miniaturization, integration with classical systems, and standardized fabrication protocols. Quantum sensing represents the next-generation technological paradigm for metrology.
Abstract Quantum sensing (QS) is a rapidly developing field at the intersection of physics, biology, and nanotechnology. It holds great promise for improving how we detect biomolecules in health, diagnostics, and environmental monitoring, and this potential is reflected in the rapid development and growing interest in advanced biosensing technologies. Traditional sensing methods, while useful, often face limits in sensitivity, speed, and the ability to analyze tiny amounts or subtle changes in biomolecules. QS uses coherence, entanglement, and superposition to achieve much higher sensitivity and precision than classical techniques. These technologies rely on advanced platforms like nitrogen-vacancy centers in diamonds, quantum dots. They can measure tiny changes in magnetic fields, electric charges, or fluorescence signals caused by biomolecules like proteins, DNA, lipids, carbohydrates and metabolites. This review explains the fundamental principles behind QS and explores how various physical platforms are used to detect and study biomolecules. It highlights recent breakthroughs in detecting single molecules, monitoring enzymatic reactions in real time, and imaging biological structures with quantum-level detail. We also discuss how nanotechnology is powering the field, improving integration through nanoparticle coupling, microfluidics, and specialized bio interfaces to target and amplify signals in practical settings. This review discusses current efforts to overcome existing challenges and highlights future directions, including the development of quantum-enhanced clinical sensors, integration with artificial intelligence for data analysis, and hybrid quantum–classical sensing strategies. These advances are expected to accelerate the translation of quantum biosensing technologies from laboratory demonstrations to practical clinical and environmental applications in the coming decade.
The ability to detect and characterize single molecules in their native environments is paramount for advancing fields ranging from fundamental biology to advanced materials science. Traditional single-molecule detection methods often face limitations in terms of sensitivity, spatial resolution, and the ability to perform measurements in situ, especially in complex biological matrices. This paper explores the transformative potential of quantum-enhanced nanosensors to overcome these limitations, enabling ultrasensitive single-molecule detection directly within living systems or operational devices. We review the fundamental principles of quantum phenomena, such as entanglement, squeezing, and quantum coherence, and discuss how they can be harnessed to push sensing capabilities beyond classical limits. Various architectures of quantum-enhanced nanosensors, including those based on nitrogen-vacancy (NV) centers in diamond, quantum dots, and optomechanical systems, are examined for their unique advantages in detecting minute perturbations caused by single molecules. The paper delves into methodologies for designing, fabricating, and functionalizing these nanosensors for specific targets, emphasizing strategies for achieving high spatial resolution and robust in situ operation. We present a theoretical framework for assessing the enhanced signal-to-noise ratio and reduced detection limits offered by quantum metrology. Potential applications span real-time monitoring of biochemical reactions, early disease diagnosis, and the development of next-generation analytical tools. Finally, the challenges and future directions for realizing widespread practical implementation of quantum-enhanced nanosensors for in situ single-molecule detection are critically discussed, highlighting the interdisciplinary efforts required at the intersection of quantum physics, nanotechnology, and life sciences.
Quantum sensing is a paradigm shift in measurement science. It uses the intrinsic quantum properties of particles and their wave functions, such as superposition, entanglement, and coherence, to achieve unparalleled sensitivity, precision, and miniaturization. This paper provides a practical engineering perspective on quantum sensing, linking foundational quantum principles to real-world applications. It reviews key enabling technologies, such as single-photon detectors, which can detect individual photons with high efficiency and low noise; nitrogen vacancy (NV) centers in diamonds, which sense nanoscale magnetic and electric fields at room temperature; and Rydberg atoms, which detect precise electromagnetic fields using optical techniques. Additionally, we examine the integration of quantum sensing approaches with optical fiber systems, high-lighting advances in distributed sensing capabilities enabled by quantum detectors. The discussion emphasizes the advantages of quantum measurement techniques over classical methods. Finally, it outlines the emerging domain of quantum sensing applications and the ongoing miniaturization and cost reduction of quantum devices, demonstrating their potential to transform multiple scientific and industrial fields.
In the field of optics and photonics, plasmonic sensors have garnered considerable interest due to their outstanding sensitivity and impressive capacity to control light at the nanoscale. These sensors enable the integration of biochemical sensing platforms by exploiting the combination of enhanced and localized electromagnetic fields at the metal–dielectric interface, and they operate effectively below the diffraction limit. The performance of conventional plasmonic sensors, despite their practical development and commercial success, remains inherently constrained by classical noise constraints, owing to the quantum fluctuations of light, known as the shot-noise limit. Recent advances have introduced quantum optical resources such as entangled and squeezed light states to overcome inherent classical restrictions, thus giving rise to the quantum plasmonic sensing field. This interdisciplinary field combines the ability to enhance electric field capabilities with the precision of quantum metrology, enabling ultrasensitive chemical and biological detection that surpasses classical precision thresholds. In the last decades, theoretical models and experimental demonstrations have greatly advanced the development of quantum plasmonic sensors, improving our comprehension of quantum light–matter interactions and facilitating novel nanoscale sensing designs. This chapter provides a comprehensive overview of the fundamental principles, latest developments, and major concepts that have driven progress in quantum plasmonic sensing and shows that quantum components are being integrated into plasmonic systems, thereby transforming optical sensing to the quantum level.
Quantum metrology provides a route to overcome practical limits in sensing devices. It holds particular relevance to biology, where sensitivity and resolution constraints restrict applications both in fundamental biophysics and in medicine. Here, we review quantum metrology from this biological context, focusing on optical techniques due to their particular relevance for biological imaging, sensing, and stimulation. Our understanding of quantum mechanics has already enabled important applications in biology, including positron emission tomography (PET) with entangled photons, magnetic resonance imaging (MRI) using nuclear magnetic resonance, and bio-magnetic imaging with superconducting quantum interference devices (SQUIDs). In quantum metrology an even greater range of applications arise from the ability to not just understand, but to engineer, coherence and correlations at the quantum level. In the past few years, quite dramatic progress has been seen in applying these ideas into biological systems. Capabilities that have been demonstrated include enhanced sensitivity and resolution, immunity to imaging artifacts and technical noise, and characterization of the biological response to light at the single-photon level. New quantum measurement techniques offer even greater promise, raising the prospect for improved multi-photon microscopy and magnetic imaging, among many other possible applications. Realization of this potential will require cross-disciplinary input from researchers in both biology and quantum physics. In this review we seek to communicate the developments of quantum metrology in a way that is accessible to biologists and biophysicists, while providing sufficient detail to allow the interested reader to obtain a solid understanding of the field. We further seek to introduce quantum physicists to some of the central challenges of optical measurements in biological science.