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In Situ Regeneration of Si-based ARROW-B Surface Plasmon Resonance Biosensors.

Hsu HF, Lin YT, Huang YT, Lu MF, Chen CH - J Med Biol Eng (2015)

Bottom Line: SPR was used to monitor the regeneration processes.The experimental results show that the sensing response did not significantly change after the sensor was reused more than 10 times.In situ regenerations of the sensors were achieved.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu, Taiwan.

ABSTRACT

Si-based antiresonant reflecting optical waveguide type B (ARROW-B) surface plasmon resonance (SPR) biosensors allow label-free high-sensitivity detection of biomolecular interactions in real time. The ARROW-B waveguide, which has a thick guiding layer, provides efficient coupling with a single-mode fiber. The Si-based ARROW-B SPR biosensors were fabricated by using the standard semiconductor fabrication processes with a single-step lithography. A fluid flow system was designed to transport samples or analytes. The waveguide consists of propagation and SPR sensing regions. The propagation regions in the front and rear of the SPR sensing region have a symmetric cladding structure to isolate them from environmental changes. A high-index O-ring is used to seal the liquid flow channel. The intensity interrogation method was used to characterize the sensors. The sensitivity of the biosensors was 3.0 × 10(3) µW/RIU (refractive index unit) with a resolution of 6.2 × 10(-5) RIU. An in situ regeneration process was designed to make the sensors reusable and eliminate re-alignment of the optical measurement system. The regeneration was realized using ammonia-hydrogen peroxide mixture solutions to remove molecules bound on the sensor surface, such as self-assembled 11-mercapto-1undecanoic acid and bovine serum albumin. SPR was used to monitor the regeneration processes. The experimental results show that the sensing response did not significantly change after the sensor was reused more than 10 times. In situ regenerations of the sensors were achieved.

No MeSH data available.


Cross-section of ARROW-B SPR biosensor
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Fig2: Cross-section of ARROW-B SPR biosensor

Mentions: In the sensing region, an adjustment layer is directly deposited on the upper first-cladding layer of the ARROW-B waveguide, and then the metal films are evaporated on the adjustment layer. Gold film is widely applied because of its great durability, good corrosion resistance, low electrical resistivity and overall chemical inertness. However, gold film shows poor adherence to dielectric materials [15]. In order to improve adherence between gold and dielectric materials, a chromium layer was utilized. The transfer matrix method was used to simulate the performance of the ARROW-B waveguide structures. As shown in Fig. 1a, the thickness of the gold film (dau) dominates the sensitivity of the sensor. The thickness of the gold film was chosen as 15 nm for high sensitivity and fabrication reliability. A high-index Si3N4 adjustment layer was introduced to shift the SPR resonance condition to a different superstrate index. As shown in Fig. 1b, the SPR dip shifts to a larger superstrate index with better sensitivity with increasing Si3N4 film thickness. Although better sensitivity was obtained when the thickness of the adjustment layer was between 0.14 and 0.16 μm, the thickness of the adjustment layer was chosen as 0.12 μm in order to avoid fabrication errors that deteriorate biosensor performance. In addition, later we show that the sensitivity can be enhanced by increasing the sensing length without changing the superstrate index of the SPR dip. Therefore, the sensing range of the refractive index can be tuned with a fixed adjustment layer. The cross-section of the Si-based ARROW-B sensor is shown in Fig. 2. The front and rear waveguides with upper cladding layers can support low-loss propagation of light even when a high-index O-ring is applied on the surface for biomedical assays. The devices were fabricated using available standard semiconductor processes.Fig. 1


In Situ Regeneration of Si-based ARROW-B Surface Plasmon Resonance Biosensors.

Hsu HF, Lin YT, Huang YT, Lu MF, Chen CH - J Med Biol Eng (2015)

Cross-section of ARROW-B SPR biosensor
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4491115&req=5

Fig2: Cross-section of ARROW-B SPR biosensor
Mentions: In the sensing region, an adjustment layer is directly deposited on the upper first-cladding layer of the ARROW-B waveguide, and then the metal films are evaporated on the adjustment layer. Gold film is widely applied because of its great durability, good corrosion resistance, low electrical resistivity and overall chemical inertness. However, gold film shows poor adherence to dielectric materials [15]. In order to improve adherence between gold and dielectric materials, a chromium layer was utilized. The transfer matrix method was used to simulate the performance of the ARROW-B waveguide structures. As shown in Fig. 1a, the thickness of the gold film (dau) dominates the sensitivity of the sensor. The thickness of the gold film was chosen as 15 nm for high sensitivity and fabrication reliability. A high-index Si3N4 adjustment layer was introduced to shift the SPR resonance condition to a different superstrate index. As shown in Fig. 1b, the SPR dip shifts to a larger superstrate index with better sensitivity with increasing Si3N4 film thickness. Although better sensitivity was obtained when the thickness of the adjustment layer was between 0.14 and 0.16 μm, the thickness of the adjustment layer was chosen as 0.12 μm in order to avoid fabrication errors that deteriorate biosensor performance. In addition, later we show that the sensitivity can be enhanced by increasing the sensing length without changing the superstrate index of the SPR dip. Therefore, the sensing range of the refractive index can be tuned with a fixed adjustment layer. The cross-section of the Si-based ARROW-B sensor is shown in Fig. 2. The front and rear waveguides with upper cladding layers can support low-loss propagation of light even when a high-index O-ring is applied on the surface for biomedical assays. The devices were fabricated using available standard semiconductor processes.Fig. 1

Bottom Line: SPR was used to monitor the regeneration processes.The experimental results show that the sensing response did not significantly change after the sensor was reused more than 10 times.In situ regenerations of the sensors were achieved.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu, Taiwan.

ABSTRACT

Si-based antiresonant reflecting optical waveguide type B (ARROW-B) surface plasmon resonance (SPR) biosensors allow label-free high-sensitivity detection of biomolecular interactions in real time. The ARROW-B waveguide, which has a thick guiding layer, provides efficient coupling with a single-mode fiber. The Si-based ARROW-B SPR biosensors were fabricated by using the standard semiconductor fabrication processes with a single-step lithography. A fluid flow system was designed to transport samples or analytes. The waveguide consists of propagation and SPR sensing regions. The propagation regions in the front and rear of the SPR sensing region have a symmetric cladding structure to isolate them from environmental changes. A high-index O-ring is used to seal the liquid flow channel. The intensity interrogation method was used to characterize the sensors. The sensitivity of the biosensors was 3.0 × 10(3) µW/RIU (refractive index unit) with a resolution of 6.2 × 10(-5) RIU. An in situ regeneration process was designed to make the sensors reusable and eliminate re-alignment of the optical measurement system. The regeneration was realized using ammonia-hydrogen peroxide mixture solutions to remove molecules bound on the sensor surface, such as self-assembled 11-mercapto-1undecanoic acid and bovine serum albumin. SPR was used to monitor the regeneration processes. The experimental results show that the sensing response did not significantly change after the sensor was reused more than 10 times. In situ regenerations of the sensors were achieved.

No MeSH data available.