Development of a novel microfluidic biosensing platform integrating micropillar array electrode and acoustic microstreaming techniques.

Quantifying biomarkers at the early stage of the disease is challenging due to the low abundance of biomarkers in the sample and the lack of sensitive techniques. This article reports the development of a novel microfluidic electrochemical biosensing platform to address this challenge. The electrochemical sensing is achieved by utilizing a micropillar array electrode (μAE) coated with 3D bimetallic Pt-Pd nanotrees to enhance the sensitivity. A bubble-based acoustic microstreaming technique is integrated with the device to increase the contact of analyte molecules with the surface of electrodes to further enhance the electrochemical performance. The current density of Pt-Pd NTs/μAE with acoustic microstreaming is nearly 22 times that of the bare planar electrode in potassium ferrocyanide solution. The developed biosensor has demonstrated excellent sensing performance. For hydrogen peroxide detection, both the Pt-Pd NTs/μAE and acoustic microstreaming contribute to the sensitivity enhancement. The current density of the Pt-Pd NTs/μAE is approximatively 28 times that of the bare μAE. With acoustic microstreaming, this enhancement is further increased by nearly 1.6 times. The platform has a linear detection range of 5-1000 μM with a LOD of 1.8 μM toward hydrogen peroxide detection, while for sarcosine detection, the linear range is between 5 and 100 μM and LOD is 2.2 μM, respectively. Furthermore, the sarcosine biosensing shows a high sensitivity of 667 μA mM∙cm. Such a sensing platform has the potential as a portable device for high sensitivity detection of biomarkers.