A surface functionalized nanoporous titania integrated microfluidic biochip

Abstract

We present a novel and efficient nanoporous microfluidic biochip consisting of a functionalized chitosan/anatase titanium dioxide nanoparticles (antTiO2-CH) electrode integrated in a polydimethylsiloxane (PDMS) microchannel assembly. The electrode surface can be enzyme functionalized depending on the application. We studied in detail cholesterol sensing using the cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) functionalized chitosan supported mesoporous antTiO2-CH microfluidic electrode. The available functional groups present in the nanoporous antTiO2-CH surface in this microfluidic biochip can play an important role for enzyme functionalization, which has been quantified by the X-ray photoelectron spectroscopic technique. The Brunauer-Emmett-Teller (BET) studies are used to quantify the specific surface area and nanopore size distribution of titania nanoparticles with and without chitosan. Point defects in antTiO2 can increase the heterogeneous electron transfer constant between the electrode and enzyme active sites, resulting in improved electrochemical behaviour of the microfluidic biochip. The impedimetric response of the nanoporous microfluidic biochip (ChEt-ChOx/antTiO2-CH) shows a high sensitivity of 6.77 kΩ (mg dl(-1))(-1) in the range of 2-500 mg dl(-1), a low detection limit of 0.2 mg dl(-1), a low Michaelis-Menten constant of 1.3 mg dl(-1) and a high selectivity. This impedimetric microsystem has enormous potential for clinical diagnostics applications.

Electrochemical impedimetric biosensors for food safety

“…EIS of the EIB for SEB was performed at a biased potential of 0.1 V (vs. an Ag/AgCl reference electrode), in the absence or presence of 10 mg/mL SEB in 0.3% NaCl solution Fig. 3 Schematic illustration of (A) the structure and construction, and (B) detection and measurement process, of EIB nanoporous metal oxides and orderly structured carbon composites as the electrode substrate, to increase the surface area and sensitivity of EIBs (Ali et al, 2014;Ania et al, 2018;Bonanni et al, 2012;Chai and Takhistov, 2012). Metal nanoparticles have been used to intensify the electrochemical signal outputs from EIBs (Derkus et al, 2014;Lin et al, 2019;Peng et al, 2006).…”

“…Mercury, platinum, graphite, gold, stainless steel, silicon, and aluminum are the most frequently used materials for the electrode substrate (Săndulescu et al, 2015 ). There have been a number of studies on the use of nanoporous metal oxides and orderly structured carbon composites as the electrode substrate, to increase the surface area and sensitivity of EIBs (Ali et al, 2014 ; Ania et al, 2018 ; Bonanni et al, 2012 ; Chai and Takhistov, 2012 ). Metal nanoparticles have been used to intensify the electrochemical signal outputs from EIBs (Derkus et al, 2014 ; Lin et al, 2019 ; Peng et al, 2006 ).…”

Amine-Functionalized MoO3@RGO Nanohybrid-Based Biosensor for Breast Cancer Detection

“…The D value (Table ) is found to be highest in the case of APTES/MoO 3 @RGO/ITO, i.e., 8.06 × 10 –12 cm 2 s –1 , depicting the mesoporous behavior of MoO 3 @RGO, due to the high aspect ratio of one-dimensional MoO 3 and the RGO substrate that promoted better electron conduction path from the electrolyte. However, after anti-HER-2 immobilization onto APTES/MoO 3 @RGO surface, the D value decreased to 5.9 × 10 –12 cm 2 s –1 and 4.3 × 10 –12 cm 2 s –1 for BSA/anti-HER-2/APTES/MoO 3 @RGO/ITO indicated the presence of anti-HER-2 and BSA that exhibited the insulating behavior which further slowed the diffusion process . Further, the HET rate was determined from the EIS studies (Figure a).…”

“…However, after anti-HER-2 immobilization onto APTES/MoO 3 @RGO surface, the D value decreased to 5.9 × 10 −12 cm 2 s −1 and 4.3 × 10 −12 cm 2 s −1 for BSA/anti-HER-2/APTES/MoO 3 @RGO/ITO indicated the presence of anti-HER-2 and BSA that exhibited the insulating behavior which further slowed the diffusion process. 55 Further, the HET rate was determined from the EIS studies (Figure 8a). The HET was found to be the highest (3 × 10 −7 cm s −1 ) in case of the APTES/MoO 3 @RGO/ITO with respect to APTES/ MoO 3 /ITO (1.9× 10 −7 cm s −1 ) and APTES/RGO/ITO (2.3 × 10 −7 cm s −1 ) (see the Supporting Information).…”

Inhibition of Epithelial–Mesenchymal Transition and Tissue Regeneration by Waterborne Titanium Dioxide Nanoparticles

“…Nanoscale titanium dioxide (TiO 2 ) is among the most widely manufactured NPs being applied to medicine, cosmetics, and food industries. TiO 2 NPs are used as transducer materials for microfluidic biosensors to obtain enhanced catalytic activity and improved stability and sensitivity. , As an example of medical application, such microfluidic devices have been used for the detection of biomarkers of breast cancer . TiO 2 NPs are also capable of delivering a wide range of chemical compounds, antibodies, or functional nucleic acids for cancer therapy. , In addition, TiO 2 NPs are extensively used as ingredients of food additives, cosmetics, and sunscreens .…”