Enzymatic Preparation and Characterization of Spherical Microparticles Composed of Artificial Lignin and TEMPO-Oxidized Cellulose Nanofiber

Abstract

A one-pot and one-step enzymatic synthesis of submicron-order spherical microparticles composed of dehydrogenative polymers (DHPs) of coniferyl alcohol as a typical lignin precursor and TEMPO-oxidized cellulose nanofibers (TOCNFs) was investigated. Horseradish peroxidase enzymatically catalyzed the radical coupling of coniferyl alcohol in an aqueous suspension of TOCNFs, resulting in the formation of spherical microparticles with a diameter and sphericity index of approximately 0.8 μm and 0.95, respectively. The ζ-potential of TOCNF-functionalized DHP microspheres was about −40 mV, indicating that the colloidal systems had good stability. Nanofibrous components were clearly observed on the microparticle surface by scanning electron microscopy, while some TOCNFs were confirmed to be inside the microparticles by confocal laser scanning microscopy with Calcofluor white staining. As both cellulose and lignin are natural polymers known to biodegrade, even in the sea, these woody TOCNF−DHP microparticle nanocomposites were expected to be promising alternatives to fossil resource-derived microbeads in cosmetic applications.

Synthesis and structural design of microspheres comprising cellulose nanofibers and artificial lignin polymer by enzyme-mediated Pickering emulsion templating

“…27 The DHPs were successfully synthesized in the presence of TOCNF via a one-pot, one-step aqueous process without any organic solvents, resulting in the formation of particles of several hundred nanometers in size, which were smaller than those required in cosmetics. 28 Lignin nanoparticles have been produced by spray-drying methods; however, the use of black powders in cosmetic applications is limited. 29 Therefore, the fabrication of microparticles by using various CNFs and non-black lignin remains challenging.…”

Preparation of spherical microparticles composed of cellulose nanofiber and cellulose diacetate via Pickering emulsion templating

“…Thus, challenges remain for marine biodegradability of cosmetic microparticles. A one-pot and one-step enzymatic synthesis of spherical microparticles composed of dehydrogenative polymers of coniferyl alcohol as a typical lignin precursor and TOCNF has been reported (Fukuda et al 2021).…”

Effects of Solvent Polarity on Nanostructure Formation of Spray-Dried TEMPO-Oxidized Cellulose Nanofiber Particles

“…Liquid-phase methods have been used to prepare TOCN-based particles by polymerizing monomers in a TOCN suspension. 7,8 At first, the monomer and other reactants are mixed with the TOCN suspension. Then, subsequent polymerization produces core/shell structures with TOCNs as the shells.…”

“…One of the most significant hurdles is the difficulty of transferring the nanoscale properties of TOCNs to the macro level, particularly in particle forms. , Various approaches have been proposed for preparing TOCN particles, e.g., liquid-phase and aerosol methods. Liquid-phase methods have been used to prepare TOCN-based particles by polymerizing monomers in a TOCN suspension. , At first, the monomer and other reactants are mixed with the TOCN suspension. Then, subsequent polymerization produces core/shell structures with TOCNs as the shells.…”