Supporting Information to paper
Porous silicon nanoparticles as scavengers of hazardous viruses
L A Osminkina1, V Yu Timoshenko1, I P Shilovsky2, G V Kornilaeva3, S N Shevchenko1, M B
Gongalsky1, K P Tamarov1, S S Abramchuk1, V N Nikiforov1, M R Khaitov2, and E V Karamov3
1
M.V. Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
NRC Institute of Immunology of FMBA, Laboratory of Nano-and Biomedical Technologies, 115478
Moscow, Russia
3
D.I. Ivanovsky Institute of Virology, 123098 Moscow, Russia
2
E-mail: osminkina@vega.phys.msu.ru
Section 1S: In vitro experiments
In order to investigate the infection rate caused by HIV virions we have used 180 μL
suspensions of CEM SS cells at concentration of 3.5•105 in 96-well plates. The cell suspensions
were infected with 20 μL of supernatants of SiNP-virion mixtures prepared at different
concentrations of SiNPs. After 24 hours incubation the residual virions, which were not bound
with cells, were removed by low speed centrifugation at 2000 rpm for 10 min. The cell
containing sediment was re-suspended in 200 µL of fresh DMEM solution and the cells were
incubated for 5 days. The infection rate of CEM SS cells was counted from the optical
absorption measurements at wavelength 450 nm using a certified commercial test systems on
p24 antigen of HIV-1 («Bio-RAD», France and "Vector – Best”, Russia).
In the experiments with RSV we have used MA-104 cells incubated into 96-well plate (104
cells/well) in DMEM for 1 day. Then the cells were washed with serum free DMEM and were
infected with the supernatant of SiNP-RSV. The cells with supernatant were incubated for 8
days. The infection rate at each SiNP concentration was counted by averaging the results in four
wells with 100 μL /well. A cytopathic effect of RSV was evaluated by using optical microscopy
to detect the characteristic syncytium formation from the cells. The virus titer was calculated by
the Spearman-Kärber formula as follows: TCID50 = (Χo – (d/2) + d(Ʃ ri/ni)), where TCID50 is
50% tissue culture infectious dose, Χo = log10 of the reciprocal of the lowest dilution at which
all wells are positive, d = log10 of the dilution factor (the difference between the log dilution
intervals), ni = number of wells used at each dilution, ri = number of positive wells (out of ni), Ʃ
ri/ni = sum of the proportion of positive wells (beginning at the lowest dilution showing 100%
positive result).
Section 2S: Nanoparticle characterization
Fig. S1 (a) TEM image of SiNPs, fabricated by mechanical grinding of PSi films (the film was
formed by the electrochemical etching of (100)-oriented c-Si wafers of p-type conductivity with
specific resistivity of 10-40 mΩ•cm), (b) size distribution of SiNPs obtained from the TEM
images of SiNPs deposited from diluted suspensions (the analysis was done by using ImageJ
program), (c) typical electron diffraction pattern from the prepared SiNPs.
Fig. S2 (a) A large-scale image of the TEM grid with dried suspension of SiNPs, fabricated by
mechanical grinding of PSi films formed from the heavily-doped c-Si wafers and (b) SEM image
of an agglomerate of SiNPs deposited from the same solution.
Fig. S3 Pore size distribution in different types of dried SiNPs: fabricated by mechanical
grinding of (a) c-Si wafers, (b) microporous PSi films, which were formed by electrochemical
etching of (100) oriented p-type boron-doped c-Si wafers with specific resistivity 10 Ω•cm. The
mean BET surface areas of SiNPs are 260 and 200 m2 g-1, respectively.
Fig. S4 DLS data for aqueous suspensions of SiNPs, fabricated by mechanical grinding of c-Si
wafers (curve 1), mesoporous (curve 2) and microporous (curve 3) PSi films, which were formed
by electrochemical etching of (100) oriented p-type boron-doped c-Si wafers with specific
resistivity of 10-40 mΩ•cm and 10 Ω•cm, respectively.
Fig. S5 FTIR absorbance spectra of SiNPs fabricated by mechanical grinding of c-Si wafers
(curve 1), mesoporous (curve 2) and microporous (curve 3) PSi films, which were formed by
electrochemical etching of (100) oriented p-type boron-doped c-Si wafers with specific
resistivity of 10-40 mΩ•cm and 10 Ω•cm respectively.
Fig. S6 Concentration dependence of the HIV infection rate for SiNPs fabricated by mechanical
grinding of c-Si wafers (curve 1), mesoporous (curve 2) and microporous (curve 3) PSi films,
which were formed by electrochemical etching of (100) oriented p-type boron-doped c-Si wafers
with specific resistivity of 10-40 mΩ•cm and 10 Ω•cm , respectively.
(c)
(d)
Fig. S7 (a) A large-scale TEM image of dried suspension of RSV virions; (b) a large-scale TEM
image of the dried mixture of RSV and SiNPs prepared from mesoporous PSi; (c) electron
diffraction pattern of SiNPs; (d) a TEM image for the dried mixture of RSV and SiNPs detected
at certain diffraction angle indicated by white dashed circle in panel (c).
Fig. S8 DLS data for an aqueous suspension of SiNPs in PBS (blue curve), a mixture of SiNPs
and HIV suspension (black curve) and its supernatant (red curve). SiNPs were prepared by
mechanical grinding of mesoporous PSi films formed by electrochemical etching of (100)
oriented p-type boron-doped c-Si wafers with specific resistivity of 10-40 mΩ•cm. The
concentration of SiNP and HIV were 1 g/L and 70000 TCID50, respectively. The suspensions od
SiNPs and HIV were mixed in Vortex at room temperature for 20 min and then the mixture was
centrifuged at 2500 rpm for 5 minutes to obtain the supernatant.