1、外文资料原文 OLED-Polypropylene Bio-CD Sensor Srikanth Vengasandra, Yuankun Cai, David Grewell, Joseph Shinar, and Ruth Shinarc Department of Agricultural & Biosystems Engineering Ames Laboratory - USDOE and Department of Physics & Astronomy MicroelectronicsResearchCenter and Department of Electrical and
2、Computer Engineering IowaStateUniversity, Ames, IA50011, U.S.A ABSTRACT With the goal of developing microfluidic platforms for sensing applications, flash-free micro patterns were embossed in polypropylene surfaces with ultrasonic heating for a biosensing application. The embossed features were desi
3、gned to act as reservoirs, valves, and reaction chambers to allow, in combination with a compact sensing platform, the monitoring of analyte levels using a standard PC-CD player. To generate the compact sensor, as an example, we chose the photoluminescence (PL)-based detection of lactate and glucose
4、 using an OLED-based sensing platform. Once embossed, the surface energy of the plastic substrate was chemically modified to make it hydrophilic. Reagents, placed in separate reservoirs, were directed through burst valves towards a reaction chamber via CD rotation. Lactate or glucose were monitored
5、by measuring the effect of the related dissolved oxygen level on the PL decay time of an oxygen-sensitive dye, following analyte oxidation catalyzed by a suitable specific oxidase enzyme. The results demonstrate the potential of integrating OLEDs as excitation sources in PL-based sensors with microf
6、luidic CD- based platforms, including for simultaneous multiple analyses. Keywords: Organic light-emitting diode, OLED, lab-on-a-CD, glucose sensor, lactate sensor 1. INTRODUCTION Biomedical micro electromechanical system (MEMS)-based sensing platforms fabricated on plastic substrates have the poten
7、tial of e.g., being low cost, disposable, cross-contamination free, and sensitive. Additionally, such sensors show promise for high throughput and multianalyte detection. The advantages of such a lab-on-CD-based biosensing platform include its simplicity in terms ofusage for a wide range of solution
8、s, versatility in terms of multianalyte detection feasibility, andcompact size. Moreover, valving is easily implemented in such CDs. This paper describes the use of ultrasonic micro-embossing to generate microfluidic channels, valves, reservoirs, and reaction chambers in a polypropylene (PP) PC comp
9、act disc (CD). The ultrasonic micro-embossing was used as a source of localized heat. The advantages of this technique include short cycle times, ease of de-embossing and low residual stresses. Moreover, this approach is applicable to batch and continuous manufacturing, and it is simpler relative to
10、 the more common fabrication methods, injection molding and hot embossing. Microfluidic CD architectures were generated in materials such as polycarbonate 1, polystyrene (PS) 2, polydimethy lsiloxane (PDMS) 3, and PP 4. As shown in this work, the CD can be integrated with a photoluminescence (PL)-ba
11、sed OLED sensing platform to generate a compact device for monitoring e.g., lactate and glucose. The CD materials are typically of relatively low surface energy making them hydrophobic. However, many of the functions of microfluidic devices rely on hydrophilic properties so that the channel walls ca
12、n promote capillary action and allow proper fluid flow. Thus, to increase the surface energy chemical treatment and oxidization by ozone or plasma are often used. In the example shown, analytes such as glucose and lactate were monitored by utilizing an oxygen-sensitive dye embedded in a thin film. G
13、lucose and lactate were oxidized in the presence of specific enzymes, i.e., glucose oxidase (GOx) and lactate oxidase (LOx), respectively, and oxygen. Oxygen is consumed in such reactions and in solution under specific experimental conditions the final dissolved oxygen (DO) level is related to the i
14、nitial analyte concentration 5. The enzymes can sometimes be embedded in a thin film； alternatively, they can be dissolved in solution. The consumption of DO in the oxidation reactions results in an increase in the PL intensity and the PL decay time of the oxygen-sensitive dye. In the preliminary me
15、asurements shown below, the OLED pixel array and the sensing film were structurally integrated by attaching two glass substrates, on which they were separately fabricated, back-to-back. The PL was monitored using a photomultiplier tube (PMT)； small-size Si photodiode arrays, compatible with the desi
16、gn of the OLED pixels, are also usable and will lead to more compact, field-deployable sensors. A more compact sensor can be obtained also by integrating, in addition to the OLED excitation source and the sensing film, a thin film-based photodetector (PD). Such PDs based on amorphous or nanocrystalline Si are currently under development 6,7, however, their current slow speed does not allow monitoring oxygen in the t mode. Organic PDs are also suitable for such integration and possibly, for measuring of suitable luminophores. 2. EXPERIMENTAL PROCEDURE 2.1. Materials
