Highly Selective Detection of Carbon Monoxide in Living Cells by Palladacycle Carbonylation-Based Surface Enhanced Raman Spectroscopy Nanosensors

Abstract

A novel nanosensor was explored for the highly selective detection of intracellular carbon monoxide (CO) by surface enhanced Raman spectroscopy (SERS) on the basis of palladacycle carbonylation. By assembling new synthesized palladacycles (PC) on the surface of gold nanoparticles (AuNPs), SERS nanosensors (AuNP/PC) were prepared with good SERS activity and reactivity with CO. When the AuNP/PC nanosensors were incubated with a CO-containing system, carbonylation of the PC assembled on AuNPs was initiated, and the corresponding SERS spectra of AuNP/PC changed significantly, which allowed the carbonylation reaction to be directly observed in situ. Upon SERS observation of CO-dependent carbonylation, this SERS nanosensor was used for the detection of CO under physiological conditions. Moreover, benefiting from the specificity of the reaction coupled with the fingerprinting feature of SERS, the developed nanosensor demonstrated high selectivity over other biologically relevant species. In vivo studies further indicated that CO in normal human liver cells and HeLa cells at concentrations as low as 0.5 μM were successfully detected with the proposed SERS strategy, demonstrating its great promise for the analytical requirements in studies of physiopathological events involved with CO.

Highly Sensitive and Selective Molecular Probes for Chromo‐Fluorogenic Sensing of Carbon Monoxide in Air, Aqueous Solution and Cells

“…Using this approach, Dhara and co-workers [28] detected CO in A549 cells incubated with PdCl 2 and CORM-3. Besides these and otherr elated reports, [29,30] Feng and co-workers have prepared CO fluorescent probesb ased on aP d 0 -mediated Tsuji-Trost elimination reaction using 3-benzothiazolyl-7-hydroxycoumarin and fluorescein fluorophores [31a,b] and this has been expanded in more recent work by the same group. [31c,d] Although the probesd escribed above display an impressive ability to detect CO in biological systems, the field would benefit from furtherr esearch to address some of the intrinsic drawbacks of each system,s uch as synthetic complexity (and hence reduced accessibility), delayedf luorescencer esponse times (typically 40-60 mins in Pd-based systems) andt he reduced fluorescencet urn-onr esponse of some of the probes (especially in aqueous solution).…”

Intracellular and Cellular Detection by SERS‐Active Plasmonic Nanostructures

“…Due to the reduction of azides by H 2 S, structure variations of 4‐AA molecules would cause changes to the SERS spectrum; thus giving rise to successful H 2 S detection. Long and co‐workers developed a CO nanosensor constructed from palladacycle‐assembled AuNPs . They indicated that the corresponding changes to the SERS fingerprint feature could be observed upon the CO‐induced carbonylation of palladacycles.…”

“…Long and co-workersd eveloped aC On anosensor constructed from palladacycle-assembled AuNPs. [27] They indicated that the corresponding changes to the SERS fingerprint feature couldb eo bserved upon the CO-induced carbonylation of palladacycles.F urther cellular studies proved that the method could provide efficient detection of CO, with al imit of 0.5 mm.R ecently,L ie tal. presented a SERS-active nanosensor forN Od etection by means of the specific reaction of NO with o-phenylenediamine in the presence of O 2 .…”

Application of nanoparticles in cancer detection by Raman scattering based techniques

“…a peptide, monoclonal antibody, affibody, or aptamer) which is coupled to the nanoparticle, can be determined by spectrally separating the SERS signatures in the detected signals from a tumor [32]. The SERS technique has excellent selectivity, rapid detection capability, high signal-to-noise ratio, non-photo bleaching features, and the use of single photo-excitation [20]. Another way to obtain larger Raman scattering enhancements, which is in close relationship with SERS, is to put the target molecule in the fractal space between aggregated colloidal nanoparticles, known as ‘hot spots’ [33–36].…”