Protein-repellent and antioxidative properties of bioactive coatings based on TEMPO oxidized cellulose nanofibrils and chitosan

Abstract

In this work, regenerated cellulose (RC) films was coated with TEMPO oxidized cellulose nanofibrils (TOCN) and chitosan (CS) by means of subsequent spin-coated deposition. The bioactivity of coatings was achieved by addition of chitosan. The chitosan was either mixed with the TOCN (TOCN+CS) and deposited on the RC film by spin-coating or deposited on the RC/TOCN bilayer film by pumping its aqueous solution at pH 5.5 over the surface of the film. The pH dependant charging behaviour of the TOCN, TOCN+CS, and CS were evaluated by pH-potentiometric titrations. The protein-repellent properties of investigated coatings were evaluated in situ using a continuous flow of bovine serum albumin (BSA) by means of quartz crystal microbalance with dissipation (QCM-D). Antioxidative activity of TOCN, CS and their amphoteric mixture was determined using the 2,2′-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) radical scavenging assay. Coating with improved protein repellent properties was obtained using TOCN+CS amphoteric mixture, but on the other hand TOCN+CS amphoteric mixture showed weaker antioxidative properties in comparison to TOCN and CS.

U ovom radu, filmovi od regenerisane celuloze (RC) su naslojeni sa TEMPO oksidisanim celuloznim nanofibrilima (TOCN) i hitozanom (CS) metodom rotirajućeg diska. Bioaktivnost prevlaka postignuta je dodavanjem hitozana. Hitozan je ili pomešan sa TOCN (TOCN+CS) i naslojen na RC film tehnikom rotirajućeg diska ili nanesen na RC/TOCN dvoslojni film propumpavanjem njegovog vodenog rastvora, pH vrednosti 5,5, preko površine filma. Naelektrisanje TOCN, TOCN+CS i CS u zavisnosti od pH je okarakterisano pH-potenciometrijskim titracijama. Protein-odbijajuća svojstva ispitivanih prevlaka određena su in situ, u kontinualnom toku goveđeg serumskog albumina (BSA) primenom kvarc-kristal mikrovage sa praćenjem disipacije (QCM-D). Antioksidativna svojstva TOCN, CS i TOCN+CS amfoterne mešavine su određena metodom inhibicije radikala 2,2′-azino-bis(3-etil benzotiazolin-6-sulfonske kiseline). Prevlaka sa poboljšanim protein-odbijajućim svojstvima je dobijena upotrebom TOCN+CS amfoterne mešavine, ali sa druge strane TOCN+CS amfoterna mešavina je pokazala slabija antioksidativna svojstva u poređenju sa TOCN i CS.