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Keywords:

  • cellulases;
  • cellulose films;
  • cleaning protocol;
  • enzymes;
  • sensors

Abstract

In this work an enzymatic treatment is proposed as a preparative, cleaning protocol to remove cellulose films from resonators and sensors. Quartz crystal and surface plasmon gold sensors, coated with ultrathin films of cellulose are used in studies of molecular (for example, polymer and surfactant) adsorption. The sensors are usually recycled after removal of the film, with limited success, after one of two treatments, either hot acid or ammoniac solutions. In the proposed, improved protocol a mixture of cellulases from Aspergillus species, are used as a pre-treatment to facilitate the release of the cellulose film from the surfaces of the sensors. Two concentrations of NaCl solutions were considered in the enzymatic treatment, 1 and 10 mM, at given enzyme solution concentration, temperature and pH. It was found that after 80 min, the water contact angle after treatment with both salt concentration conditions reached a plateau. The average water contact angle after integration of the enzymatic and ammoniac treatments was found to be low enough, between 6.4 and 7.1 deg to allow reuse the sensors. It is concluded that the use of the ammoniac cleaning solution after the enzymatic treatment is a very convenient, safe and less time consuming way to remove the cellulose films from the sensors to be recycled.