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Measuring Interactions between Fluorescent Probes and Lignin in Plant Sections by sFLIM Based on Native Autofluorescence
Published on: January 2, 2020
On the surface interactions of proteins with lignin
Carlos Salas1, Orlando J Rojas, Lucian A Lucia
1Department of Forest Biomaterials, North Carolina State University, Raleigh, North Carolina 27695, United States.
ACS Applied Materials & Interfaces
|December 14, 2012
Summary
This study quantifies soy protein (glycinin and β-conglycinin) adsorption onto lignin films. Undenatured proteins adsorb more extensively, indicating strong interactions at the solid-liquid interface.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Protein-Lignin Interactions
Background:
- Lignins are widely used in protein formulations, yet their interfacial interactions remain poorly understood.
- Soy proteins, glycinin (11S) and β-conglycinin (7S), are key components in many food and biomaterial applications.
Purpose of the Study:
- To investigate the surface interactions between lignin and soy proteins (11S and 7S) at the solid-liquid interface.
- To quantify the adsorption extent and hydration of interfacial layers.
- To determine the influence of ionic strength and protein denaturation on these interactions.
Main Methods:
- Quartz Crystal Microgravimetry (QCM) to measure adsorption mass.
- Surface Plasmon Resonance (SPR) to analyze interfacial layer properties.
- Controlled variations in solution ionic strength and protein denaturation (using 2-mercaptoethanol and urea).
Main Results:
- Adsorption of undenatured glycinin (11S) and β-conglycinin (7S) onto lignin films was significantly greater than denatured proteins.
- A substantial amount of water was coupled to the adsorbed protein layers, indicating high hydration.
- Protein adsorption led to a notable reduction in water contact angle (~40° for 11S, ~35° for 7S), suggesting strong nonspecific interactions.
Conclusions:
- Protein conformation and solution conditions (ionic strength, denaturation) critically influence soy protein adsorption onto lignin.
- Strong, nonspecific interactions drive the adsorption of undenatured soy proteins onto lignin surfaces.
- The findings provide crucial insights into biomacromolecular interactions relevant for formulation design.
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