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A method based on light scattering to estimate the concentration of virus particles without the need for virus particle standards.

Makra I, Terejánszky P, Gyurcsányi RE - MethodsX (2015)

Bottom Line: Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards.Instead, as standards, well-characterized polymeric nanoparticle solutions are used.The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied.

View Article: PubMed Central - PubMed

Affiliation: MTA-BME "Lendület" Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, Budapest 1111, Hungary.

ABSTRACT
Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards. We have adapted a static light scattering based method for the quantification of virus particles (shown for poliovirus) without the need of virus particle standards. Instead, as standards, well-characterized polymeric nanoparticle solutions are used. The method is applicable for virus particles acting as Rayleigh scatterers, i.e., virus particles with equivalent diameters up to ca. 1/10th of the wavelength of the scattered monochromatic light (∼70 nm diameter). Further limitations may arise if the refractive index of the virus is unavailable or cannot be calculated based on its composition, such as in case of enveloped viruses. The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied. The method consists of: •Measuring the intensity of the light scattered by viruses suspended in an aqueous solution.•Measuring the intensity of the light scattered by polymeric nanoparticles of known concentration and comparable size with the investigated virus particle.•The concentration of virus nanoparticles can be calculated based on the two measured scattered light intensities by knowing the refractive index of the dispersing solution, of the polymer and virus nanoparticles as well as their relative sphere equivalent diameters.

No MeSH data available.


Related in: MedlinePlus

Calculated concentrations (Eq. (2)) of the latex nanoparticles with the use of other (different size) latex particle as standard (see legend). The solid line denotes the perfect correlation while the dashed lines are shifted by one order of magnitude up and down with respect to the perfect correlation.
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fig0025: Calculated concentrations (Eq. (2)) of the latex nanoparticles with the use of other (different size) latex particle as standard (see legend). The solid line denotes the perfect correlation while the dashed lines are shifted by one order of magnitude up and down with respect to the perfect correlation.

Mentions: The method was validated by comparing the nominal concentration values of the three different size nanoparticles with the values calculated with Eq. (2). For each size nanoparticles the concentrations diameters were calculated using the other two size nanoparticles as standards, e.g., the concentrations of different solutions of 25 nm diameter nanoparticles were calculated using 45 and 73 nm nanoparticles as standards. The results are shown in Fig. 5 and illustrates the accuracy of the method. Large discrepancies are apparent only where the linear dependence of the scattered light intensity vs. nanoparticle concentration is not valid.


A method based on light scattering to estimate the concentration of virus particles without the need for virus particle standards.

Makra I, Terejánszky P, Gyurcsányi RE - MethodsX (2015)

Calculated concentrations (Eq. (2)) of the latex nanoparticles with the use of other (different size) latex particle as standard (see legend). The solid line denotes the perfect correlation while the dashed lines are shifted by one order of magnitude up and down with respect to the perfect correlation.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487338&req=5

fig0025: Calculated concentrations (Eq. (2)) of the latex nanoparticles with the use of other (different size) latex particle as standard (see legend). The solid line denotes the perfect correlation while the dashed lines are shifted by one order of magnitude up and down with respect to the perfect correlation.
Mentions: The method was validated by comparing the nominal concentration values of the three different size nanoparticles with the values calculated with Eq. (2). For each size nanoparticles the concentrations diameters were calculated using the other two size nanoparticles as standards, e.g., the concentrations of different solutions of 25 nm diameter nanoparticles were calculated using 45 and 73 nm nanoparticles as standards. The results are shown in Fig. 5 and illustrates the accuracy of the method. Large discrepancies are apparent only where the linear dependence of the scattered light intensity vs. nanoparticle concentration is not valid.

Bottom Line: Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards.Instead, as standards, well-characterized polymeric nanoparticle solutions are used.The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied.

View Article: PubMed Central - PubMed

Affiliation: MTA-BME "Lendület" Chemical Nanosensors Research Group, Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, Budapest 1111, Hungary.

ABSTRACT
Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards. We have adapted a static light scattering based method for the quantification of virus particles (shown for poliovirus) without the need of virus particle standards. Instead, as standards, well-characterized polymeric nanoparticle solutions are used. The method is applicable for virus particles acting as Rayleigh scatterers, i.e., virus particles with equivalent diameters up to ca. 1/10th of the wavelength of the scattered monochromatic light (∼70 nm diameter). Further limitations may arise if the refractive index of the virus is unavailable or cannot be calculated based on its composition, such as in case of enveloped viruses. The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied. The method consists of: •Measuring the intensity of the light scattered by viruses suspended in an aqueous solution.•Measuring the intensity of the light scattered by polymeric nanoparticles of known concentration and comparable size with the investigated virus particle.•The concentration of virus nanoparticles can be calculated based on the two measured scattered light intensities by knowing the refractive index of the dispersing solution, of the polymer and virus nanoparticles as well as their relative sphere equivalent diameters.

No MeSH data available.


Related in: MedlinePlus