Characteristics of Polysilicon Wire Glucose Sensors with a Surface Modified by Silica Nanoparticles/γ-APTES Nanocomposite

Jing-Jenn Lin,Po-Yen Hsu,Jheng-Jia Jhuang,You-Lin Wu

doi:10.3390/s110302796

Abstract

This report investigates the sensing characteristics of polysilicon wire (PSW) glucose biosensors, including thickness characteristics and line-width effects on detection limits, linear range and interference immunity with membranes coated by micropipette/spin-coating and focus-ion-beam (FIB) processed capillary atomic-force-microscopy (C-AFM) tip scan/coating methods. The PSW surface was modified with a mixture of 3-aminopropyl-triethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs). We found that the thickness of the γ-APTES+NPs nonocomposite could be controlled well at about 22 nm with small relative standard deviation (RSD) with repeated C-AFM tip scan/coatings. The detection limit increased and linear range decreased with the line width of the PSW through the tip-coating process. Interestingly, the interference immunity ability improves as the line width increases. For a 500 nm-wide PSW, the percentage changes of the channel current density changes (ΔJ) caused by acetaminophen (AP) can be kept below 3.5% at an ultra-high AP-to-glucose concentration ratio of 600:1. Simulation results showed that the line width dependence of interference immunity was strongly correlated with the channel electrical field of the PSW biosensor.

Highlights

As any subtle biological or chemical change in the human body may affect the performance of living systems, the development of high-sensitivity biosensors to detect low concentrations of molecules such as DNA, proteins, etc., has been a high-profile effort in recent years
We focus on the effect of different line widths on the sensitivity and selectivity of the detection capabilities of the polysilicon wire (PSW) glucose sensor
Because the spread area of the γ-APTES+NPs nanocomposite is much larger than the maximum area that can be scanned by the AFM

Summary

Introduction

As any subtle biological or chemical change in the human body may affect the performance of living systems, the development of high-sensitivity biosensors to detect low concentrations of molecules such as DNA, proteins, etc., has been a high-profile effort in recent years. Leiber’s research team used silicon nanowire (SiNW) to develop a nano-biosensor, many studies have pointed out that this one-dimensional structure has the potential to serve as the foundation for a new generation of nanotechnology biosensors [1,2,3,4,5] This is because this type of structure allows for a highly sensitive and simple detection method, resulting in SiNW being successfully deployed in chemical, biomedical and physiological signal research. Our FIB processed C-AFM tip has been proven to be effective in coating very small amounts of solution to the device surface We believe this technology can effectively help in the fabrication of very small and highly reproducible nano-semiconductor biosensors [8,10]. We will demonstrate that the strength of the PSW channel electric field and blood glucose detection ability are well correlated

Experimental Section

Results and Discussion

Characteristics of Sensitivity Performance of the PSW Sensor

Characteristics of Selectivity Performance of the PSW Sensor

DS qμ n

Conclusions