Novel techniques for refractive index determination of single nanoparticles in suspension

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$Novel techniques for refractive index determination of single nanoparticles in suspension$ Böing 2, Auguste Sturk 2, Rienk Nieuwland 2, and Ton G.

1 Novel techniques for refractive index determination of single nanoparticles in suspension Edwin van der Pol 1,2 Frank A. Coumans 1,2, Anita N. Böing 2, Auguste Sturk 2, Rienk Nieuwland 2, and Ton G. van Leeuwen 1 February 8th, Biomedical Engineering and Physics; 2 Laboratory Experimental Clinical Chemistry, Academic Medical Center, Amsterdam, The Netherlands 1

2 Acknowledgements Academic Medical Center Biomedical Engineering and Physics Laboratory Experimental Clinical Chemistry European Association of National Metrology Institutes (EURAMET) The European Metrology Research Programme (EMRP) is jointly funded by the EMRP participating countries within EURAMET and the European Union University of Oxford Chris Gardiner University of Birmingham Paul Harrison NanoSight Ltd. Patrick Hole Andrew Malloy Jonathan Smith 2

3 Introduction to extracellular vesicles cells release vesicles (e.g. exosomes): biological nanoparticles with receptors, DNA, RNA specialized functions clinically relevant van der Pol et al., Pharmacol Rev (2012) 3

4 Add extracellular vesicle concentrations to hematology reference tables Source: Academic Medical Center 4

$Determine refractive index to identify vesicles vesicles (1.36 n 1.$

5 Determine refractive index to identify vesicles vesicles (1.36 n 1.45 for d > 500 nm)* lipoproteins (n = ) protein aggregates (n = ) * Konokhova et al., J Biomed Opt (2012) 5

6 Refractive index to relate scatter to diameter 3 flow cytometry is widely used to detect single vesicles refractive index provides scatter to diameter relation Coumans et al., SPIE2015 #

$Refractive index of vesicles is unknown?$

7 Refractive index of vesicles is unknown? refractive index of vesicles is unknown detection range is unknown Coumans et al., SPIE2015 #

8 Methods for refractive index determination of single nanoparticles in suspension Refractive index matching (multiple particles) 8

9 Methods for refractive index determination of single nanoparticles in suspension vesicles 500 nm Multi-angle light scattering* (single particles) Refractive index matching (multiple particles) * graph adopted from: Konokhova et al., J Biomed Opt (2012) 9

10 Problem no method to determine the refractive index of single nanoparticles (< 500 nm) in suspension Method Single particles Size (nm) Refractive index matching All Multi-angle light scattering flow cytometry

$Goal determine the refractive index of$ identify vesicles in plasma provide

11 Goal determine the refractive index of single nanoparticles in suspension identify vesicles in plasma provide insight in vesicle detection by flow cytometry 11

12 Methods - single particle tracking (SPT) obtain particle diameter d by tracking the Brownian motion of single particles (Stokes-Einstein equation) measure scattering power P derive particle refractive index n(p,d) from Mie theory 12

13 Methods - setup Commercial instrument Nanosight NS-500 microscope objective NA = 0.4 EMCCD + particles in solution laser beam power = 45 mw wavelength = 405 nm glass figure adopted from Malvern Instruments Ltd, UK 13

14 Methods - data acquisition and processing 14

15 Methods - approach calibration measure light scattering of beads describe measurements by Mie theory validation determine refractive index of beads mixture application determine refractive index of vesicles 15

16 Results - scattering cross section vs. diameter of polystyrene beads by Mie theory 16

17 Results - scattering cross section vs. diameter of polystyrene beads 17

18 Results - scattering cross section vs. diameter of polystyrene and silica beads 18

19 Methods - approach calibration measure light scattering of beads describe measurements by Mie theory validation determine refractive index of beads mixture application determine refractive index of vesicles 19

20 Results - scattering cross section vs. diameter of a mixture of polystyrene and silica beads SPT 20

21 Results - scattering cross section vs. diameter of a mixture of polystyrene and silica beads SPT 21

$Results - refractive index and size distribution$

22 Results - refractive index and size distribution of a mixture of polystyrene and silica beads SPT 22

23 Methods - approach calibration measure light scattering of beads describe measurements by Mie theory validation determine refractive index of beads mixture application determine refractive index of vesicles 23

24 Results - scattering power versus diameter of urinary vesicles SPT 24

25 Results - size and refractive index distribution of urinary vesicles 25

26 Conclusions single particle tracking can be used to determine the refractive index of nanoparticles in suspension mean refractive index of urinary vesicles is 1.37 E. van der Pol et al., Nano Lett (2014) 26

27 Discussion accuracy: measurement error = 2.0 % precision: coefficient of variation (CV) = 2.8 % SPT 27

28 Discussion increase precision by increasing minimum tracklength consequence: number of tracked particles decreases 28

29 Outlook: hybrid backscattering resistive pulse sensing for refractive index determination backscattering intensity resistive pulse sensing nanopore membrane CV diameter = 7% resistive pulse sensor: commercial instrument (qnano, Izon Ltd) 29

30 Towards vesicles as biomarkers for disease backscattering intensity fluorescence + Raman scattering* resistive pulse sensing van der Pol et al., SPIE2015, 2:10 PM, # edwinvanderpol.com 30

Manual Rosetta Calibration v

Manual Rosetta Calibration v Rosetta Calibration... 2 The problems... 2 The solution... 2 How does Rosetta Calibration work?... 2 Applicability... 2 Rosetta Calibration beads... 4 Storage... 4 Preparation... 4 Measurement... 5 Rosetta