EQuBS-Lab - Research

Our research focuses on the development of quantum sensing and novel spectroscopy methods to study chemical processes, biophysics, and life sciences. A central concept that empowers this endeavor is known as "optically addressable spin qubits". Simply put, these are two-level quantum systems based on engineerable molecules or materials, which can be initialized, read out, and coherently controlled by lasers and microwaves, playing essential roles in all branches of "Quantum 2.0" technologies. From such measurements, we obtain rich information about the composition, dynamics, and function of biological systems with exquisitely high sensitivity, precision, and spatial resolution.

To do this, we rely on multidisciplinary knowledge involving quantum information science and engineering (QISE), physics, chemistry, life sciences, engineering, and computer simulation. These novel analytical approaches/strategies allow us and researchers from all over the world to study important biological systems and to enhance the understanding of the molecular mechanisms of cellular processes. In essence, the convergence of quantum sensing and biology holds the promise to reshape the landscape of healthcare for the better.

Experimental techniques

NV-based NMR and quantum sensing

This cutting-edge technique is made possible by utilizing the unique spin and optical properties of the nitrogen-vacancy (NV) defect in diamond crystal, which serves as a quantum bit (or "qubit"). The preparation and manipulation of the NV qubit is achieved through an interplay of laser and microwave. The NV-based quantum sensor is exquisitely sensitive to several physical quantities, such as magnetic field, temperature, and crystal strain.

Because of its high sensitivity, the NV-based quantum sensor can detect the magnetic field fluctuations generated by single molecules, enabling nanoscale NMR experiments. The NV-NMR is a burgeoning field with lots of unknowns, and of course, opportunities. It is the primary sensing technique used in the EQuBS lab.

Interested readers are directed to some classic reviews:

1. Schirhagl, et al. Annu. Rev. Phys. Chem. 2014, 65, 83. DOI: 10.1146/annurev-physchem-040513-103659

2. Allert, et al. Chem. Commun. 2022, 58, 8165. DOI: 10.1039/D2CC01546C

Conventional solution NMR

Conventional NMR relies on the bulk magnetization generated by the Boltzmann distribution of nuclear spins at different energy levels inside a magnetic field. Microwave pulses that match with the transition frequencies (i.e. resonance) are used to manipulate the orientation of the magnetization. As the system spontaneously returns to equilibrium, it induces electric signals in the NMR probe that are subsequently amplified and recorded. By analyzing these NMR signals, we can learn about the structures and dynamics of the molecules in the sample at atomic resolution. Conventional NMR is a mature and versatile technology that has broad applications in chemistry, biology, material science, physics, geology, and medicine.

Cell biology and molecular biology

Molecular/cell biology techniques allow us to prepare and optimize biological samples at wish: tissue, cell, lipid membrane, protein, DNA & RNA, metabolite, etc. Getting the relevant biological sample is a critical step for quantum biosensing.

Single molecule imaging

Single-molecule fluorescence microscopy takes advantage of the optical properties of dye molecules or fluorescent proteins to probe biology. This powerful tool-kit includes TIRF, confocal, super-resolution, FRET, light-sheet, and many other techniques for different research purposes. Some of these techniques are compatible with NV-based quantum sensing. Such integrated platforms will provide privileged opportunities to study biological systems.

Nanofabrication

Image creator: solarseven

Nanofabrication (nanofab) is the manufacture of materials with nanometer dimensions. The typical process involves deposition, lithography, etching, and characterization. Consumer products such as computer chips and camera sensors all rely on industry-scale nanofab. To achieve quantum control of NV qubit, designing and nanofabricating devices is an indispensable component.

Our research takes a multidisciplinary effort to develop quantum biosensing technology. This pursuit is empowered by many scientific disciplines (defined in the traditional ways), including but not limited to:

Physics – AMO; Solid-State/Condensed Matter Physics; Biophysics

Chemistry – Physical Chemistry; Analytical Chemistry; Chemical Biology; Material Chemistry; Surface Chemistry; Spectroscopy

Engineering – Electrical and Computer Engineering; Material Science & Engineering; Automation and Control; Hybrid Circuits

Life Science – Protein Science & Engineering; Molecular Biology; Cell Biology