Diamond nano-optode for fluorescent measurements of pH and temperature

Abstract

Nano-optodes with a diamond core coated with a double stimuli-responsive polymeric shell reversibly respond to pH and temperature changes.

High-throughput nitrogen-vacancy center imaging for nanodiamond photophysical characterization and pH nanosensing

“…Compared to previous reports on ND pH sensing, our technique is considerably simpler as it does not require ND polymer coating or a microwave generator for spin state manipulation. 27,31,54 Our demonstration of pH direct reporting at a single-particle level (Fig. 5c) opens the possibility to perform pH nanosensing experiments (such as pH mapping inside living cells) using single-particle tracking.…”

“…Characterization methods are also essential for new ND bio-sensing assays. For instance, Raabova et al showed that the charge state of a NV center in polymer-coated NDs could be used to detect pH changes; 31 this was achieved by measuring changes in the ND's emission spectra to differentiate the two photoactive charge states of the NV center (NV − and NV 0 ; NV + is non-photoactive), since NV 0 has its emission 60 nm blue-shifted compared to NV − (see Fig. 1b ).…”

pH Sensitive Dextran Coated Fluorescent Nanodiamonds as a Biomarker for HeLa Cells Endocytic Pathway and Increased Cellular Uptake

“…Recently, it has also been demonstrated that nanodiamonds containing nitrogen-vacancy (NV) centres can be used to sense their magnetic surroundings with unprecedented sensitivity with nanoscale resolution [ 17 , 18 ]. When combined with pH-responsive polymers, their location can imply intracellular pH changes [ 19 ]. Charge conversion of NV centres can also be used as an indicator for pH but requires complex equipment for readout [ 20 ].…”

Diamond quantum thermometry: From foundations to applications

“…To overcome the particle variations, it seems necessary to calibrate dD/dT in situ prior to the target measurement, as performed in the case of other fluorescence nanothermometers [31,166,167]. Further, this strategy for particle calibration is expected to be common to all types of ND family, such as critically magnetic coupled NDs [49] and chemically functionalized NDs [168,169], because these additional coupling components likely increase the inhomogeneity in dD/dT .…”