Implantable biosensors are still limited with regard to long-term monitoring of biological functions, and there is no report in the literature of their use for months or more. The main reason for this limitation is that biosensors are not fully biocompatible or they are bioabsorbed by the biological tissues. In this Project, we aim at fabricating flexible enzymatic biosensors that may be implantable for long-term monitoring (of the order of months), using ink-jet printing. The biosensors will be made with the natural polymers silk fibroin and bacterial cellulose, with horseradish peroxidase (HRP) serving as prototypical enzyme. Silk fibroin was selected because it increases enzyme lifetime, and it will be used in aqueous solutions for preparing the flexible supports as well as in the ink to print the enzyme-containing layer. The principle of detection for biosensing will be impedance spectroscopy, with an interdigitated architecture printed with fibroin ink containing conducting nanoparticles of Au and/or Ag. The final device will be coated with a layer of bacterial cellulose hydrogel, which is biocompatible and is not bioabsorbed rapidly by biological tissues. The combination of natural polymers and ink-jet printing may allow for the fabrication of flexible, implantable biosensors that may last for months and be potentially of low cost. Owing to the duration of the Project, in vivo tests are not planned, for which partnerships will be sought on the course of the research.
Articles published in Pesquisa para Inovação FAPESP about the scholarships: