Handheld Fluorometers for Lab-on-a-Chip Applications

Abstract

We describe the design, fabrication, and performance of a class of simple handheld fluorometers. The devices consist of a sensor along with an integrated optical filter packaged in a handheld format. The sensor is a differential active pixel sensor with in-pixel correlated double sampling fabricated in a 0.5-mu m 2-poly 3-metal complementary metal-oxide semiconductor process and has a readout noise of 175.3 muV, reset noise of 360 muV, dynamic range of 59 dB, and conversion gain of 530 nV/e(-) . The filter is a high rejection chromophore embedded in a polymer film which is cast onto the chip. We show the results of bioassays utilizing two different single color fluorometers constructed by using the chromophores 2-(2'-hydroxy 5'-methylphenyl) benzotriazole and Sudan II with long-pass wavelengths of 400 nm and 540 nm, respectively. The bioassays measures metabolic activity and viability of biological cells, which are useful for cytotoxicity and pathogen detection applications.

A hand-held electronic tongue based on fluorometry for taste assessment of tea

“…However, only a few commercially available hand-held fluorometers (Anonymous 1; Anonymous 2, 2002; Anonymous 3) with visible light-emitting diodes (LEDs) are available specifically for identifying chlorophyll. Researchers have recently developed portable (Chen, 2005(Chen, , 2008 and hand-held (Farmer et al, 2005;Patounakis et al, 2006;Eltoukhy et al, 2006;Nelson et al, 2009) fluorometers for various applications. However, prototypes of portable or hand-held fluorometers use only visible light (such as 375 nm blue from LEDs or laser diodes), limited the exciting wavelengths that could be used in the fluorometric analysis.…”

“…However, the use of photo-detectors in newly developed hand-held fluorometers is still limited by the fact that high voltages are required to run them. Charge-coupled devices (CCDs) (Kostov et al, 2009) and CMOS (Eltoukhy et al, 2006;Nelson et al, 2009) detectors can also be utilized in hand-held devices, but their costly and complicated electronic integration is serious consideration. Photo-detectors with acceptable sensitivity are more useful for scaling down and simplifying electronic circuits for compact hand-held fluorometric instruments.…”

Linear-Logarithmic Wide-Dynamic-Range Active Pixel Sensor with Negative Feedback Structure Using Gate/Body-Tied Photodetector with an Overlapping Control Gate

“…(1)(2)(3) Many photodetector (PD) elements are available in a CMOS, including n+/p-well, p+/ n-well, and n-well/p-sub junctions, which are used for imaging applications . (1,4) These…”

A CMOS-based lab-on-chip array for the combined magnetic stimulation and opto-chemical sensing of neural tissue

“…For example, CMOS-based imagers using parasitic pnjunction photodiodes have been developed into novel lab-on-chip platforms for applications in fluorometry to measure metabolic activity and viability of biological cells [2]. Similarly, ISFET-based chemical sensors are becoming increasingly popular due to the fact that they can be fabricated in unmodified CMOS technology.…”