Corrales Ureña, Yendry ReginaYendry ReginaCorrales UreñaGätjen, LindaLindaGätjenVieira Nascimento, MatheusMatheusVieira NascimentoLisboa-Filho, Paulo NoronhaPaulo NoronhaLisboa-FilhoLeite Cavalcanti, WelchyWelchyLeite CavalcantiNoeske, Paul-Ludwig MichaelPaul-Ludwig MichaelNoeskeRischka, KlausKlausRischka2022-03-052022-03-052016https://publica.fraunhofer.de/handle/publica/24339610.1186/s40563-016-0059-3The formation of nano-scale biofilms on hydrophilic silica surfaces from aqueous polypeptide/polysaccharide mixtures containing laccase and maltodextrin was investigated in situ with quartz crystal microbalance with dissipation monitoring (QCM-D). Surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), optically stimulated electron emission (OSEE) and atomic force microscopy (AFM) were applied for characterizing the resulting layers obtained after periods varying from a few seconds to several hours of contact between the substrate and the biopolymers formulation. The biofilm formation in contact with the aqueous laccase/maltodextrin suspension was studied at pH level 4.75, under conditions close to the isoelectric point of the enzyme. The few nanometers rough biofilms obtained were composed of a laccase/maltodextrin mixture, and their thickness was observed to steadily increase during 4 h of contact with the aqueous mixture of biopolymers. Remarkably, the still adhesive films obtained after 1 h of contact with aqueous polypeptide/polysaccharide mixture resisted a 30 min rinsing with acetate buffer. The biofilms growing process was monitored using OSEE, due to the effected attenuation of the UV-induced electron emission from the SiO2/Si substrate, which was found to be more pronounced than the attenuation of the photoelectrons from the substrate which contribute to the XPS signals. Layers as thin as 1 nm were detected by the OSEE.en668journal article