Single and Multiple Internal Reflection poly(dimethylsiloxane) absorbance-based biosensors

Abstract In this paper it is shown how the inclusion of the air mirrors allows both the enhancement of the performance of the Single Internal Reflection (SIR) systems and the implementation of a new type of highly sensitive absorbance-based biosensor, based on Multiple Internal Reflection (MIR). Both configurations are fabricated in a single-mask step and replicated using Poly(dimethylsiloxane) (PDMS) using soft lithographic techniques. Experimental results confirm the ray-tracing predictions: if the air mirror is accurately defined, the propagating light matches the conditions of Total Internal Reflection (TIR) at the PDMS–air interface, which results in a complete reflection of the light towards the flow cell. Hence, the inclusion of such microoptical components reduces the integration time more than 30 times while increasing the SNR and the sensitivity, reaching limits of detection (LOD) close to the μM level. On the other hand, in the MIR configuration, the shape of the air mirrors has been modified so as to allow the partial focusing of the light at adequate places of the flow cell. With the recursive positioning of air mirrors, the optical path length has been meaningfully lengthened without a dramatic increase of the volume. The experimental results also match with the ray-tracing predictions and have allowed obtaining LOD between 110 nM (PMIR-II) and 41 nM (RMIR) with sensitivities up to three times higher than the SIR configuration. The obtained results are auspicious for the implementation of the absorbance-based photonic lab-on-a-chip systems.

[1]  A D Stroock,et al.  An integrated fluorescence detection system in poly(dimethylsiloxane) for microfluidic applications. , 2001, Analytical chemistry.

[2]  G. Whitesides,et al.  Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane). , 1998, Analytical chemistry.

[3]  L. Lechuga,et al.  An integrated optical interferometric nanodevice based on silicon technology for biosensor applications , 2003 .

[4]  D. J. Harrison,et al.  A multireflection cell for enhanced absorbance detection in microchip‐based capillary electrophoresis devices , 2000, Electrophoresis.

[5]  Gwo-Bin Lee,et al.  Micromachined flow cytometers with embedded etched optic fibers for optical detection , 2003 .

[6]  A. M. Jorgensen,et al.  Lab-on-a-chip with integrated optical transducers. , 2006, Lab on a chip.

[7]  S Büttgenbach,et al.  Poly(dimethylsiloxane) hollow Abbe prism with microlenses for detection based on absorption and refractive index shift. , 2004, Lab on a chip.

[8]  W. Kuhr,et al.  Immobilization and detection of DNA on microfluidic chips. , 2001, Talanta.

[9]  Volker Thomsen,et al.  Limits of Detection in Spectroscopy , 2003 .

[10]  N. Rochat,et al.  Multiple internal reflection infrared spectroscopy using two-prism coupling geometry: A convenient way for quantitative study of organic contamination on silicon wafers , 2000 .

[11]  A. Manz,et al.  Glass chips for high-speed capillary electrophoresis separations with submicrometer plate heights , 1993 .

[12]  Luke P. Lee,et al.  Total internal reflection-based biochip utilizing a polymer-filled cavity with a micromirror sidewall. , 2004, Lab on a chip.

[13]  A. Llobera,et al.  Analysis of optochemical absorbance sensors based on bidimensional planar ARROW microoptics , 1999 .

[14]  Wanjun Wang,et al.  Numerical and experimental study of an out-of-plane prealigned refractive microlens fabricated using ultraviolet lithography method , 2004 .

[15]  S Büttgenbach,et al.  Optimization of poly(dimethylsiloxane) hollow prisms for optical sensing. , 2005, Lab on a chip.

[16]  S. Buttgenbach,et al.  Polymer microlenses with modified micromolding in capillaries (MIMIC) technology , 2005, IEEE Photonics Technology Letters.

[17]  Development of a positive pressure driven micro-fabricated liquid chromatographic analyzer through rapid-prototyping with poly(dimethylsiloxane) Optimizing chromatographic efficiency with sub-nanoliter injections. , 2000, Talanta.