**3.4 Analyte mass minimization with flow confinement**

Increasing the mass of the sample delivered to the inlet of the microfluidic channel can mitigate the lack of analyte consumed near the binding surface [22]. However, we show in this study that this lack of analyte can be solved by adding flow confinement in front of the sensitive surface which gives a significant improvement to the binding reaction. **Figure 9** shows the time progression of the normalized complex concentration without and with confinement flow at the adsorption phase for two amounts of

**Figure 8.** *Time advancement of the normalized surface concentration with different flow confinement velocities.*


**Table 4.**

*Detection time and drop percentage for the microfluidic biosensor with various flow confinement rates.*

*Enhancement of SARS-CoV-2 Detection Time for Integrated Flow Confinement Microfluidic… DOI: http://dx.doi.org/10.5772/intechopen.104802*

**Figure 9.** *Flow confinement effect on the adsorption reaction surface for different input analyte amounts.*

analyte at the microchannel inlet. In the case of a biosensor with a confinement effect, although the concentration of analyte at the entrance is reduced (10<sup>5</sup> μmol/m<sup>3</sup> ), an improvement in the binding reaction has been observed.
