Related Experiment Video
Updated: Feb 27, 2026
Covalent Binding of Antibodies to Cellulose Paper Discs and Their Applications in Naked-eye Colorimetric Immunoassays
Published on: October 21, 2016
Visualization and Quantification of IgG Antibody Adsorbed at the Cellulose-Liquid Interface
Vikram Singh Raghuwanshi1, Jielong Su1, Christopher J Garvey2
1Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University , Clayton, Victoria 3800, Australia.
Insights
A new method uses deuterated cellulose to visualize and quantify antibody adsorption for eco-friendly biodiagnostics. This technique enhances contrast, enabling clear imaging of antibody layers on cellulose surfaces.
Area of Science:
- Biomolecular science
- Materials science
- Surface science
Background:
- Quantifying biomolecule adsorption at interfaces is crucial for biodiagnostics.
- Developing eco-friendly biodiagnostic tools requires precise interface analysis.
- Current methods face challenges in visualizing adsorbed molecules on cellulose.
Purpose of the Study:
- To develop a novel methodology for visualizing and quantifying antibody adsorption onto cellulose.
- To enhance scattering contrast at the cellulose-liquid interface using deuteration.
- To establish a foundation for improved eco-friendly biodiagnostic platforms.
Main Methods:
- Deuterated cellulose (DC) synthesis using heavy water and deuterated glycerol.
- Preparation of hydrogenated cellulose (HC) and DC thin films on silicon substrates.
- X-ray reflectivity (XR) for film characterization.
- Neutron reflectivity (NR) for interface analysis and adsorption visualization.
- Quartz crystal microbalance with dissipation monitoring (QCM-D) for quantification.
Main Results:
- Successful synthesis of homogeneous and smooth HC and DC films.
- Neutron reflectivity revealed significant swelling of cellulose films in solution.
- Clear visualization of Immunoglobulin G (IgG) antibody adsorption on DC films due to enhanced contrast.
- Quantification of adsorbed IgG layer thickness (127 ± 5 Å) and formation of a partial monolayer.
- Demonstrated significant difference in scattering length density (SLD) between DC and IgG in D2O.
Conclusions:
- Deuteration of cellulose significantly enhances scattering contrast for NR analysis.
- The developed method enables precise visualization and quantification of antibody adsorption.
- This approach offers a promising pathway for developing advanced eco-friendly biodiagnostics.
Abstract:
Quantification of adsorbed biomolecules (enzymes, proteins) at the cellulose interface is a major challenge in developing eco-friendly biodiagnostics. Here, a novel methodology is developed to visualize and quantify the adsorption of antibody from solution to the cellulose-liquid interface. The concept is to deuterate cellulose by replacing all nonexchangeable hydrogens from the glucose rings with deuterium in order to enhance the scattering contrast between the cellulose film surface and adsorbed antibody molecules. Deuterated cellulose (DC) was obtained from bacterial (Gluconacetobacter xylinus strain) cellulose, which was grown in heavy water (D2O) media with a deuterated glycerol as a carbon source. For comparison, hydrogenated cellulose (HC) was obtained from cellulose acetate. Both HC and DC thin films were prepared on silicon substrate by spin coating. X-ray reflectivity (XR) shows the formation of homogeneous and smooth film. Neutron reflectivity (NR) at the liquid/film interface reveals swelling of the cellulose film by a factor of 2-3× its initial thickness. An Immunoglobulin G (IgG), used as a model antibody, was adsorbed at the liquid-solid interface of cellulose (HC) and deuterated cellulose (DC) films under equilibrium and surface saturation conditions. NR measurements of the IgG antibody layer adsorbed onto the DC film can clearly be visualized, in sharp contrast in comparison to the HC film. The average thickness of the IgG adsorbed layer onto cellulose films is 127 ± 5 Å and a partial monolayer is formed. Visualization and quantification of adsorbed IgG is shown by large difference in scattering length density (SLD) between DC (7.1 × 10-6 Å-2) and IgG (4.1 × 10-6 Å-2) in D2O, which enhanced the scattering contrast in NR. Quartz crystal measurements (QCM-D) were used as a complementary method to NR to quantify the adsorbed IgG over the cellulose interface.
