Label-Free Single-Particle Surface-Enhanced Raman Spectroscopy Detection of Phosphatidylserine Externalization on Cell Membranes with Multifunctional Micron-Nano Composite Probes

Abstract

Monitoring externalization of phosphatidylserine (PS) and gaining insights into molecular events of cell membrane damage are significant for programmed cell death studies. Herein, by encapsulating zeolitic imidazole frameworks-8 with plasmonic gold nanoparticles to form micron-nano composites and using them as a single-particle surface-enhanced Raman spectroscopy (SERS) substrate, we succeeded in real-time discriminating and monitoring the externalization of PS on cell membranes during electrostimulus-induced apoptosis. The micron-nano composite probe provides rich "hot spots" and robust anchoring capacity for cell membranes, achieving the capture and label-free single-particle SERS detection of the externalized PS. By this method, the dynamic PS externalization process differences between cancerous cells and normal cells were clearly revealed of which the cell membrane damage of cancerous cells was more serious than that of normal cells. This method is versatile and robust for monitoring the externalization of PS and uncovering related cell membrane damage mechanisms. This work also broadens the application of metal−organic framework materials for advanced biomedical applications.

Wet-Chemical Electro-Plasmonic Modulation of Metasurfaced Cell–Electrode Interfaces for Effective and Selective Entropic Killing of Cancer Cells

“…To test this, the cell viability of MCF-7 cells cultured on the AuNP-NM/ITO electrode and bare ITO electrode was examined under different voltages from 0 to 0.8 V for 5 min using live/dead fluorescence dyes (calcein-AM/propidium iodide (PI)). As shown in Figure S17, the cells covered on the electrodes gradually died with increasing applied voltage, which is consistent with our previous work. ,− However, the metasurfaced AuNP-NM/ITO electrodes can markedly reduce the voltage threshold by ∼0.4 V to easily trigger cell apoptosis, compared to the bare ITO electrode.…”

“…The result is consistent with our work reported previously. 27,36,37 Figure 3b shows the typical roomtemperature current−voltage profiles of the tested different electrodes in solution recorded in the dark. The dark current was approximately 0.054 mA at a 1.2 V applied bias for the bare ITO electrode.…”

Surface enhanced Raman scattering for probing cellular biochemistry

“…Cells subjected to electrical stimulation show this translocation, which was probed using zinc based metal organic frameworks decorated with gold nanoparticles, where zinc is able to interact with the phosphate head groups of the lipid membrane. 63 Following the increasing 1152 cm −1 band related to phosphatidylserine and the decrease of a phosphate signal with increasing applied voltages, the effect is greater for cancerous cells when compared to non-cancerous cells. 63 The phosphatidylserine in the outer membrane leaflet can also interact strongly with silver cations, and an in situ reduction by hydroxylamine generates a highly localized SERS probe that allows the characterization of the membrane composition during the apoptotic process.…”

“… 63 Following the increasing 1152 cm −1 band related to phosphatidylserine and the decrease of a phosphate signal with increasing applied voltages, the effect is greater for cancerous cells when compared to non-cancerous cells. 63 The phosphatidylserine in the outer membrane leaflet can also interact strongly with silver cations, and an in situ reduction by hydroxylamine generates a highly localized SERS probe that allows the characterization of the membrane composition during the apoptotic process. 64 …”

Electrostimulus-associated PD-L1 expression on cell membrane revealed by immune SERS nanoprobes

“…13,14 Jin's studies used the ES method to realise the release of cytochrome c, activation of caspase-3 and exteriorisation of phosphoserine to accelerate cell apoptosis. [15][16][17] Compared with drug treatments, ES is a fast and controlled method that can avoid the shortcomings of chemical drugs, which require a long period and have uncontrollable side effects when exogenous matter enters the cells. However, the impacts of ES on the dynamic expression of PD-L1 have not been revealed.…”