Adsorption of Proteins on Colloidal Lignin Particles for Advanced Biomaterials

Abstract

Coating of colloidal lignin particles (CLPs), or lignin nanoparticles (LNPs), with proteins was investigated in order to establish a safe, self-assembly-mediated modification technique to tune their surface chemistry. Gelatin and poly-L-lysine formed the most pronounced protein corona on the CLP surface, as determined by dynamic light scattering (DLS) and zeta potential measurements. Spherical morphology of individual protein coated CLPs was confirmed by transmission electron (TEM) and atomic force (AFM) microscopy. A mechanistic adsorption study with several random coiled and globular model proteins was carried out using quartz crystal microbalance with dissipation monitoring (QCM-D). The three-dimensional (3D) protein fold structure and certain amino acid interactions were highly dependent on the protein adsorption on the lignin surface. The main driving forces of protein-lignin affinity were electrostatic, hydrophobic, and Van der Waals interactions, and hydrogen bonding. The relative contributions of these interactions were highly dependent on the ionic strength of the surrounding medium. Capillary electrophoresis (CE) and Fourier transform infrared spectroscopy (FTIR) provided further evidence about the adsorption-enhancing role of specific amino acid residues such as serine and proline. These results have high impact on the utilization of lignin as colloidal particles in 2 biomedicine and biodegradable materials, as the protein corona enables tailoring of the CLP surface chemistry for intended applications.

Lignin for Nano‐ and Microscaled Carrier Systems: Applications, Trends, and Challenges

“…Cationic polymers carrying quaternary amine headgroups are well known for their antimicrobial properties, but cationic lignin particles have not been systematically studied for their possible cytoxicity for mammalian cells. Instead of cationic polymers, LNPs coated with proteins are expected to improve biocompatibility and reduce clearance rate; however, these important aspects are yet to be demonstrated under physiological conditions.…”

Use of mechanically ground lignocellulosic native fines (LF) in the all-cellulosic composite filaments: fines properties and plasticizers

“…During the turbidity measurement, we did not see any sedimentation within 30 days for this (4.8 m-LF) grade. The observed significant improvement of the colloidal stability of the LF with decreasing particle size can be explained by the relative increase of Brownian forces relative to the gravitational forces (Larson 1999).…”

“…Lignin has many interesting properties and is currently being researched intensively for new areas of application (Azadi et al 2013). Lignin (like wood) is a hydrophilic material (Mantanis and Young 1997;Notley and Norgren 2010) that binds proteins (Leskinen et al 2017), and has a compatibilising effect on composites (Chirayil et al 2014;Leskinen et al 2017).…”

Colloidal Lignin Particles as Adhesives for Soft Materials

“…Adsorption of model proteins on lignin surface was studied by quartz crystal microbalance with dissipation (QCM-D, Q-Sense E4, Sweden) at different pHs [42]. For the analysis, golden plates were oxidized with UV-light (10 min), spin-coated with polystyrene (PS) and lignin (WS 650, Laurell Technologies Corp., USA) [50].…”

“…Proteins adsorb on lignin surface. The extent of the interactions depends on the physico-chemical properties of the biomolecule resulting from the three-dimensional (3D) structure and amino acid composition of the protein [50,42]. To show potential to exploit actual by-product from industry, purified -casein, previously used in wood [60] and food [21] adhesives was used a model protein for the surface functionalization of CLPs.…”