Összes szerző

Gaál Anikó

az alábbi absztraktok szerzői között szerepel:

Farkasné Bebesi Tímea
Spectroscopic study of extracellular vesicles using plasmonic gold nanoparticles

Aug 30 - szerda

15:30 – 17:00

II. Poszterszekció

P36

Spectroscopic study of extracellular vesicles using plasmonic gold nanoparticles

Tímea Bebesi Farkasné1,2, Marcell Pálmai1, Imola Csilla Szigyártó1, Anikó Gaál1, Orsolya Bálint-Hakkel3, Attila Bóta1, Zoltán Varga1, Judith Mihály1

1 Research Centre for Natural Sciences, Institute if Material and Environmental Sciences

2 Eötvös Lóránd University, Hevesy György PhD School of Chemistry

3 Centre for Energy Research, Institute of Technical Physics and Material Sciences

Extracellular vesicles (EVs), spontaneously released by cells, play an important role in intercellular communication. Due to their special size and composition (lipid bilayer-bounded nanosystems, usually smaller than 200 nm, containing both proteins and RNA), they play diagnostic, prognostic and therapeutic roles, for example, they can be "new generation" biomarkers of various diseases.

IR spectroscopy, especially attenuated total reflection (ATR), is rapidly emerging as a label-free promising tool for molecular profiling of EVs. However, the relative low number of extracellular vesicles (~1010 particle/mL) and possible impurities (protein aggregates, lipoproteins, buffer molecules, etc.) present in EV samples might result in poor signal-to-noise (S/N) ratio. The plasmonic properties of gold nanoparticles (AuNPs) are used in many characterization techniques, inclusive characterization and testing of EVs. Surface-enhanced infrared spectroscopy (SEIRA – Surface-enhanced IR absorption) using plasmonic nanoparticle, however, is still an unexploited method.

Nanosized gold nanoparticles and tailored nanostructures with confined electromagnetic near-fields were prepared, characterized and tested with model-EVs (EV-like liposomes) and red blood cell derived EVs. A concentration dependent interaction was established between the citrate-stabilized gold nanoparticles and the lipid bilayers, which strongly affected both the plasmonic behaviour of AuNPs and the bilayers lipid organization. At appropriate extracellular vesicle – gold nanoparticle ratio a 6-fold maximum enhancement was obtained in the lipid spectral signatures. Exploiting the fine details of EV – gold nanoparticles interaction, further surface modifications of gold nanoobjects are planned, enhancing the sensitivity and specificity of EV detection enabling a strong platform for IR spectroscopic investigations of EVs.

Acknowledgment

This work was funded by ÚNKP-22-3-II-ELTE-507 and NKFIH K-131657, K131594, 2020-1-1-2- PIACI-KFI_2020-00021, TKP2021-EGA and KKP_22-144180 grants. ZV and MP are supported by the János Bolyai Research Scholarship of the HAS.

Varga Zoltán
Hollow Organosilica Beads: A Novel Reference Material for the Flow Cytometry Analysis of Extracellular Vesicles

Aug 30 - szerda

14:36 – 14:54

Sejtanalitika biofizikai megközelítéssel

E34

Hollow Organosilica Beads: A Novel Reference Material for the Flow Cytometry Analysis of Extracellular Vesicles

Anikó Gaál, Zoltán Varga

1 Biological Nanochemistry Research Group, Research Centre for Natural Sciences

Extracellular vesicles (EVs) are increasingly recognized as key biomarkers with significant potential in diagnostic and therapeutic applications. Their precise concentration measurement in body fluids is crucial, for which flow cytometry is currently the clinically most applicable method. This technique often uses solid polystyrene reference beads for calibration, but the disparity in refractive indices between these beads and EVs can distort accurate size determination. In response to this challenge, this study aims to prepare, characterize, and test hollow organosilica beads (HOBs) with different diameters as reference beads to set EV size gates in flow cytometry investigations.

HOBs were produced through the hard template sol-gel method, followed by a thorough analysis of their morphology, size, and colloidal stability. Their suitability as reference particles was then examined using flow cytometry. Findings indicated that HOBs exhibit a uniform size distribution and shell thickness. Further, two-angle light scattering measurements showed that HOBs scatter far less light than comparable solid silica beads due to differences in refractive indices. The scattering intensity of HOBs aligns with that expected from EVs of similar sizes.

Moreover, the study demonstrated that HOBs can be used to standardize EV concentration measurements, independent of the light scattering collection angles of the flow cytometer. Concentration measurements of platelet-derived EVs, conducted using size gates established by HOBs, showed the smallest percentage difference relative to the mean concentration, pointing to HOBs' superiority over solid beads.

In conclusion, HOBs, due to their similar structure and light scattering properties to EVs, can set size gates in nanometers, regardless of the flow cytometer's optical configuration.