Highly Sensitive Biofunctionalized Mesoporous Electrospun TiO2 Nanofiber Based Interface for Biosensing

The surface modified and aligned mesoporous anatase titania nanofiber mats (TiO2–NF) have been fabricated by electrospinning for esterified cholesterol detection by electrochemical technique. The electrospinning and porosity of mesoporous TiO2–NF were controlled by use of polyvinylpyrrolidone (PVP) as a sacrificial carrier polymer in the titanium isopropoxide precursor. The mesoporous TiO2–NF of diameters ranging from 30 to 60 nm were obtained by calcination at 470 °C and partially aligned on a rotating drum collector. The functional groups such as −COOH, −CHO etc. were introduced on TiO2–NF surface via oxygen plasma treatment making the surface hydrophilic. Cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) were covalently immobilized on the plasma treated surface of NF (cTiO2–NF) via N-ethyl-N0-(3-dimethylaminopropyl carbodiimide) and N-hydroxysuccinimide (EDC-NHS) chemistry. The high mesoporosity (∼61%) of the fibrous film allowed enhanced loading of the enzyme molecules in the TiO2–NF mat. The ChEt-ChOx/cTiO2–NF-based bioelectrode was used to detect esterified cholesterol using electrochemical technique. The high aspect ratio, surface area of aligned TiO2–NF showed excellent voltammetric and catalytic response resulting in improved detection limit (0.49 mM). The results of response studies of this biosensor show excellent sensitivity (181.6 μA/mg dL–1/cm2) and rapid detection (20 s). This proposed strategy of biomolecule detection is thus a promising platform for the development of miniaturized device for biosensing applications.