Supplementary Information
Improving the sensitivity of cellulose fiber-based lateral flow assay by incorporating a water-dissolvable polyvinyl alcohol dam
Nur Alama, Li Tonga, Zhibin Hea, Ruihua Tanga,b*, Laboni Ahsanc, Yonghao Ni a*
a Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
b College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science &
Technology, Xi’an 710021, P. R. China
c Labaid Ltd (Diagonestic and Reference Lab), Dhanmondi, Dhaka, Bangladesh
*Corresponding authors: R. Tang (tangruihua@163.com); Y. Ni (yonghao@unb.ca)
Fig. S1 Comparison study of glass fiber and cellulose fiber-based sample pad LFA. (A,B)
Schematic of glass fiber and cellulose fiber-based sample pad LFA. (a) SEM micrograph, and (b) functional group representation. A(a) Glass fiber porosity is too high comparative to B(a) cellulose fiber. Glass fiber A(b) does not have any functional group, but cellulose fiber B(b) does have. Due to the both characteristics, sample release time for cellulose fiber-based sample pad device is longer than glass fiber-based sample pad device
Fig. S2 Flow rate comparison between the glass fiber and cellulose fiber-based sample pad LFA
devices. (A) NC membrane photographs flow distance at 10, 20 and 30s (seconds); left image for cellulose fiber-based and right one for glass fiber-based sample pad device. (B) Sample flow difference over time. In every case, at the same time, the flow distance of the glass fiber-based sample pad device is longer than that of the cellulose fiber-based sample pad device
Fig. S3 Qualitative and quantitative sensitivity comparison of glass fiber and cellulose fiber-
based sample pad LFA devices. (A) LFA photographs for limit of detection (LOD) of glass fiber and cellulose fiber-based sample pad devices. LOD for the glass fiber and cellulose fiber-based device is 1000 ng mL-1 and 500 ng mL-1, respectively; indicating cellulose fiber-based device is showing 2-fold higher sensitivity. (B)Quantitative comparative measurement between the glass fiber and cellulose fiber-based devices. Quantitative analysis shows better performance of
cellulose fiber-based LFA device for all tests. (T=test line and C=control line; NS indicates error bar is not significant)
Fig. S4 Evaluation of 10 % PVA concentration effect on LFA sensitivity. For both 50 ng/mL and 500 ng/mL concentrations test line show less color intensity than previous 7.5 % concentration PVA dam LFA device. T=test line and C=control line
Fig. S5 Diameter of 7.5% PVA applied NC membrane. If the volume increases, diameter of dam zone also increases. Volume 1.5 µL covers the full width of LFA device
Fig. S6 TEM image after test run of PVA modified NC membrane (7.5%PVA, 1.5 µL), indicating that PVA has been dissolved and washed out completely
