## 2 Materials and Methods
### Experiment Design
#### 2.7.3 Biacore Assay of Bimolecular Affinity between VB (VB2) and Virus Component Proteins  
The binding affinity and kinetics of VB (VB2) and virus protein were measured using surface plasmon resonance with a BIACORE X (Biacore, Uppsala, Sweden) instrument containing a CM5 sensor chip. Virus proteins were immobilized onto each of the flow cells using NHS/EDC amine coupling chemistry. Flow cells were activated for 7 min, with a 1:1 mixture of 0.1 M \(N\)-hydroxysuccinimide and 0.1 M 3-(\(N\),\(N\)-dimethylamino)-propyl-\(N\)-ethylcarbodiimide at a flow rate of 20 \(\mu\)L/min. VBs (VB2) as  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Target** & & \multicolumn{1}{c}{**Primer**} & **References** \\ \hline Influenza virus, AH1 & Inf-AH1 & Forward; & 5\({}^{\circ}\)-CAA AGA CCC CAG GGA GCT AT:3\({}^{\circ}\) & [16] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-CAG TAG AAC CAA CTA ITC TG:3\({}^{\circ}\) & [16] \\ \cline{3-4} Influenza virus, AH3 & Inf-AH3 & Forward; & 5\({}^{\circ}\)-TTG TTG AAC CAGA CCA AGC GT:3\({}^{\circ}\) & [16] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-TCT AGT TTT TCTC TGC TG:3\({}^{\circ}\) & [16] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-TCT AGT TTT CCA GGA TAT GA:3\({}^{\circ}\) & [16] \\ \cline{3-4} Influenza virus, B & Inf-B & Forward; & 5\({}^{\circ}\)-TCT GCT TCA AGT AAA GG:3\({}^{\circ}\) & [16] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-TCT GCT TCA CTA ATT AAA GG:3\({}^{\circ}\) & [17] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-GCG CCG TGA TTT TGT TGC:3\({}^{\circ}\) & [17] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-CCG CCA AGG CAT ATT TGC:3\({}^{\circ}\) & [17] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-GCT GGA TGG CAG ACT ACT AG:3\({}^{\circ}\) & [17] \\ \cline{3-4}  & & Reverse; & 5\({}^{\circ}\)-CCC CCG AGG TCA AAC G:3\({}^{\circ}\) & [17] \\ \hline Herpes Simplex virus & & Forward; & 5\({}^{\circ}\)-CCT GGA TTGligands were injected over each of the flow cells for 2-3 min, which resulted in a surface density of 1000-1500 resonance units (RU). Surfaces were blocked with a 7-min injection of 1 M ethanolamine-HCl at pH 8.5. The running buffer used for kinetic experiments contained 10 mM HEPES at pH 7 and 150 mM NaCl (HBS-N) purchased from BIACORE. All experiments were performed at 25 \({}^{\circ}\)C at a flow rate of 20 \(\upmu\)L/min. Each analysis cycle consisted of (i) the serial dilution of each analysis being injected for 2 min over both flow cells, the Logan-immobilized and reference cells; (ii) a 3-min stabilization period; (iii) the regeneration of the Logan surface with a 30 s injection of 30 mM NaOH; (iv) a 3-min stabilization period. The signal was monitored as the ligand-immobilized flow cell minus the reference cell. The data from the buffer blank was subtracted from all of the sample runs. The normalized data were then simultaneously fit to a 1:1 binding with a mass transport model using steady-state affinity analysis in BIA Evaluation 3.1 software to obtain Kass and Kdiss parameters.  
7.4 Negative Test of Commercially Available Hygiene Products by Quantitative RT-PCR with Viral and Bacterial RNA  
Commercially available hygiene products (VB-containing moist hand towels and wet sheets) were subjected to extraction with purified water (10 mL/g). General bacteria and fungi were examined by a plate culture method using CompactDry \"Nissui\" TC and YM (Nissui Pharmaceutical Co. Ltd., Tokyo, Japan). Moist hand towel manufacturers in Japan were under instruction from the Ministry of Health, Labour, and Welfare. General bacteria count should be \(<\)100,000 colonies per sample, and no fungi should be detected [22].