title: Surface-Functionalization of Nanostructured Cellulose Aerogels by Solid State Eumelanin Coating.
abstract: Bioinspired aerogel functionalization by surface modification and coating is in high demand for biomedical and technological applications. In this paper, we report an expedient three-step entry to all-natural surface-functionalized nanostructured aerogels based on (a) TEMPO/NaClO promoted synthesis of cellulose nanofibers (TOCNF); (b) freeze-drying for aerogel preparation; and (c) surface coating with a eumelanin thin film by ammonia-induced solid state polymerization (AISSP) of 5,6-dihydroxyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA) previously deposited from an organic solution. Scanning electron microscopy showed uniform deposition of the dark eumelanin coating on the template surface without affecting porosity, whereas solid state (13)C NMR and electron paramagnetic resonance (EPR) spectroscopy confirmed the eumelanin-type character of the coatings. DHI melanin coating was found to confer to TOCNF templates a potent antioxidant activity, as tested by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays as well as strong dye adsorption capacity, as tested on methylene blue. The unprecedented combination of nanostructured cellulose and eumelanin thin films disclosed herein implements an original all-natural multifunctional aerogel biomaterial realized via an innovative coating methodology.
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S.Angelo , via Cintia 4, I-80126 Naples, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Panzella
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering "G. Natta", Politecnico di Milano , Via Mancinelli 7, I-20131 Milano, Italy.|INSTM, National Consortium of Materials Science and Technology, Local Unit Politecnico di Milano , Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.|Università degli studi e-Campus, Via Isimbardi 10, I-22060 Novedrate, Como, Italy.
authors.forename: Lucio
authors.initials: L
authors.lastname: Melone
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S.Angelo , via Cintia 4, I-80126 Naples, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pezzella
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering "G. Natta", Politecnico di Milano , Via Mancinelli 7, I-20131 Milano, Italy.|INSTM, National Consortium of Materials Science and Technology, Local Unit Politecnico di Milano , Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
authors.forename: Bianca
authors.initials: B
authors.lastname: Rossi
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering "G. Natta", Politecnico di Milano , Via Mancinelli 7, I-20131 Milano, Italy.|INSTM, National Consortium of Materials Science and Technology, Local Unit Politecnico di Milano , Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Pastori
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S.Angelo , via Cintia 4, I-80126 Naples, Italy.|CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), Florence, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Perfetti
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S.Angelo , via Cintia 4, I-80126 Naples, Italy.|CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), Florence, Italy.
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico
authors.affiliation: Department of Chemistry, Materials, and Chemical Engineering "G. Natta", Politecnico di Milano , Via Mancinelli 7, I-20131 Milano, Italy.|INSTM, National Consortium of Materials Science and Technology, Local Unit Politecnico di Milano , Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Punta
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S.Angelo , via Cintia 4, I-80126 Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: d'Ischia
mesh_terms: D000327:Adsorption; D052160:Benzothiazoles / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry* / Q000648:ultrastructure; D016166:Free Radical Scavengers / Q000737:chemistry; D005782:Gels; D008543:Melanins / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D010851:Picrates / Q000737:chemistry; D058105:Polymerization; D016062:Porosity; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D052160:Benzothiazoles; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D005782:Gels; D008543:Melanins; D010851:Picrates; D013451:Sulfonic Acids; C041877:eumelanin; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D002482:Cellulose; C004931:1,1-diphenyl-2-picrylhydrazyl; D008751:Methylene Blue