Development of a SERS strategy to overcome the nanoparticle stabilisation effect in serum-containing samples: Application to the quantification of dopamine in the culture medium of PC-12 cells

Abstract

The analysis of serum samples by surface-enhanced Raman spectroscopy (SERS) has gained ground over the last few years. However, the stabilisation of colloids by the proteins contained in these samples has restricted their use in common practice, unless antibodies or aptamers are used. Therefore, this work was dedicated to the development of a SERS methodology allowing the analysis of serum samples in a simple and easy-to-implement way. This approach was based on the pre-aggregation of the colloid with a salt solution. Gold nanoparticles (AuNPs) were used as the SERS substrate and, owing to its physiopathological importance, dopamine was chosen as a model to implement the SERS approach. The presence of this neurotransmitter could be determined in the concentration range 0.5-50 ppm (2.64-264 µM) in the culture medium of PC-12 cells, with a R of 0.9874, and at even lower concentrations (0.25 ppm, 1.32 µM) in another matrix containing fewer proteins. Moreover, the effect of calcium and potassium on the dopamine exocytosis from PC-12 cells was studied. Calcium was shown to have a predominant and dose-dependant effect. Finally, PC-12 cells were exposed to dexamethasone in order to increase their biosynthesis and release of dopamine. This increase was monitored with the developed SERS approach.

Application of a 2D Molybdenum Telluride in SERS Detection of Biorelevant Molecules

“…Therefore, we used β-sitosterol/fetal bovine serum (FBS) cell culture medium, which is commonly used during studies of the interaction between cell and diseasecausing agents or markers. 40,41 Freshly spin-coated 10 −4 M solution of sitosterol in FBS (Dulbecco's modified Eagle's medium) still shows well-distinguishable SERS spectra (Figure 4d). Although there are some overlaps with wide peaks originating from the culture medium, the fingerprint peaks of β-sitosterol are easily recognized.…”

Towards practical and sustainable SERS: a review of recent developments in the construction of multifunctional enhancing substrates

“…190 Therefore, it is also possible to construct SERS enhancing substrates which contain plasmonic nano-junctions that act simultaneously as SERS "hot spots" and molecular sieves. 191,192 For example, we have Table 2. Additional examples of separation-enhancement-in-one SERS substrates for analysis of complex real-life samples.…”

Ultra‐Stable Plasmonic Colloidal Aggregates for Accurate and Reproducible Quantitative SE(R)RS in Protein‐Rich Biomedia

“…[17] Alternatively,i ti sa lso possible to first aggregate the colloid with salt to form hot-spots before adding in the sample.H owever,t his narrows the window for SE-(R)RS analysis and adds to the irreproducibility of the measurements. [18] To test the potential of SPAs for SE(R)RS analysis in biological media, samples of adenine dissolved in 3.3 %a lbumin solution were used to provide as imple biologically-relevant test molecule in as olution whose protein content matched that of human serum. Even at much lower protein concentrations conventional colloids fail to give any SE(R)RS signals since they cannot be aggregated even with the addition of high concentrations of salt.…”