Label-Free Analysis with Multiple Parameters Separates G Protein-Coupled Receptor Signaling Pathways

Abstract

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Monitoring silica core@shell nanoparticle‐bacterial film interactions using the multi‐parametric surface plasmon resonance technique

“…The ΔPMI parameter is the dynamic intensity shift of the SPR peak minimum and can be extracted when the full SPR spectra is measured. 24 As shown in Figure 2D-F, during the growth of the S. aureus bacterial biofilms (t = 0-1300 min) the ΔPMI responses did not initially change during 200 min. After this the ΔPMI response increased rapidly and reached a maximum of 0.03-0.04 at around 400-500 min, followed by a gradual decrease and leveling out between 500 and 1300 min.…”

“…In addition to ΔPAP, the ΔPMI parameter during biofilm growth was also evaluated to assess if it would provide additional supporting information for the results obtained by measuring the ΔPAP. The ΔPMI parameter is the dynamic intensity shift of the SPR peak minimum and can be extracted when the full SPR spectra is measured 24 . As shown in Figure 2D–F, during the growth of the S. aureus bacterial biofilms ( t = 0–1300 min) the ΔPMI responses did not initially change during 200 min.…”

“…21,22 This has opened new opportunities to utilize the MP-SPR in applications that have not previously been accessible for traditional SPR techniques. Recently, novel real-time label-free analysis platforms based on the MP-SPR technique have been developed for measuring specific cell responses with small molecules/drugs 23 ; for differentiating between major G-protein coupled receptor cell signaling pathways when cells are stimulated with specific ligands for each pathway 24 and for monitoring cell uptake kinetics and efficacy of various NPs. 25 These studies have collectively shown that the MP-SPR signal response is a result of the combination of morphological changes in the cell layer, such as cell spreading or contraction, and stimulant buildup in the cells.…”

“…Previous studies where MP-SPR was used to monitor cell responses during stimulation with small molecular drugs have demonstrated that instead of analyzing ΔPAP and ΔPMI parameters separately, a plot of ΔPMI against ΔPAP responses were able to distinguish the mode of drug interaction with cells and separate various cell signaling pathways from each other. 24 Thus, as a qualitative evaluation to understand the biofilm growth process and NP interactions with the biofilm ΔPMI-ΔPAP response profiles were also plotted for the biofilm growth measurements and for the interaction measurements of differently charged CeO 2 @MSNs with biofilms (Figure 4). The ΔPMI-ΔPAP plots for all the biofilm growth measurements (Figure 3A-C) showed a linear positive slope in the beginning which changed direction at the time point when the ECM started to form and when the biofilm matured.…”