Quantum Sensing in a Physiological‐Like Cell Niche Using Fluorescent Nanodiamonds Embedded in Electrospun Polymer Nanofibers

Abstract

Fluorescent nanodiamonds (fNDs) containing nitrogen vacancy (NV) centers are promising candidates for quantum sensing in biological environments. This work describes the fabrication and implementation of electrospun poly lactic‐co‐glycolic acid (PLGA) nanofibers embedded with fNDs for optical quantum sensing in an environment, which recapitulates the nanoscale architecture and topography of the cell niche. A protocol that produces uniformly dispersed fNDs within electrospun nanofibers is demonstrated and the resulting fibers are characterized using fluorescent microscopy and scanning electron microscopy (SEM). Optically detected magnetic resonance (ODMR) and longitudinal spin relaxometry results for fNDs and embedded fNDs are compared. A new approach for fast detection of time varying magnetic fields external to the fND embedded nanofibers is demonstrated. ODMR spectra are successfully acquired from a culture of live differentiated neural stem cells functioning as a connected neural network grown on fND embedded nanofibers. This work advances the current state of the art in quantum sensing by providing a versatile sensing platform that can be tailored to produce physiological‐like cell niches to replicate biologically relevant growth environments and fast measurement protocols for the detection of co‐ordinated endogenous signals from clinically relevant populations of electrically active neuronal circuits.

Nanoscale Dynamic Readout of a Chemical Redox Process Using Radicals Coupled with Nitrogen-Vacancy Centers in Nanodiamonds

“…16 Detection of magnetic noise using relaxometry has been demonstrated for a range of paramagnetic species, including ferritin, [17][18][19][20] gadolinium, 16,[21][22][23][24][25] manganese ions, 20,26 and superparamagnetic nanoparticles 27 with the possibility of ND-based sensing inside living cells. 28 This method has high sensitivity, as evidenced by the detection of a few ferritin molecules 17 or approximately 5 gadolinium spins per Hz 1/2 in a model biological environment. 22 Recently, relaxometry has been shown useful for pH sensing, 29 and the T1 protocol has been enhanced to take into account ionization and recharging of the NV centers.…”

Diamond quantum thermometry: From foundations to applications

“…After determining neuronal nontoxicity, they applied spin-based thermometry using the CW-ODMR method and confirmed that the intracellular temperature varied by −1.36°C under a global temperature change of −2.1°C. There is another report on the formation of neural networks from a cul-ture of live differentiated neural stem cells with the help of tissue engineering technology, namely the synthetic scaffolds of electrospun polymer nanofibres incorporating NDs [228]. Furthermore, these experiments can be extended to tissue slices on multielectrode arrays in combination with thermal stimuli [229,230].…”

Sensitive magnetometry in challenging environments

“…Opening up further applications, fluorescent nanodiamonds were recently combined with biomimetic substrates used in the laboratory. ODMR spectra were obtained from live differentiated neural stem cells functioning as a connected neural network grown on fluorescent nanodiamond embedded nanofibers [250]. See [245] and references therein for a detailed review on the use of nanodiamonds in cells.…”