Low noise bipolar photodiode array protein chip based on on-chip bioassay for the detection of E. coli O157:H7

Abstract

A bipolar photodiode array (PDA) protein chip is presented for the detection of E. coli O157:H7. Through unique design of the bipolar PDA microchip, the device was able to detect E. coli O157:H7 directly on the surface of the bipolar PDA. The bipolar PDA microchip maintained low noise level in the entire process of on-chip protein assay and demonstrated high performance of analog signal processing. At every reaction step of the on-chip bioassay, stability of wet photodiode detection elements was confirmed by monitoring the variance of their photosignals with respect to the irradiated red beam. The background signal represented less than 1.8% variance with respect to maximum signal of photodiode detection elements. As a result of using the on-chip bioassay, any complicated optical alignment and components could be removed in the constructed protein chip. This protein chip enables direct optical detection of E. coli O157:H7 eliminating the need of conventional expensive microplate reader that is incompatible with size of sampling platform of protein chip. The independence of the constructed protein chip on conventional microplate reader can contribute greatly to further miniaturization of protein chip and field usable lab-on-a-chip.

Interdigitated microelectrode array-coupled bipolar semiconductor photodiode array (IMEA-PDA) microchip for on-chip electrochemiluminescence detection

“…It was also suggested that the second mode reflection minima and maxima produced by the ani-reflection siliceous layer attributed to the local extrema (Fiaccabrino et al 1998) in the overall spectral characteristics of a photodiode array optimized for a peak wavelength value centered around 620 nm. Fluorescence emissions of fluorescein and alexa fluor 647 measured using the constructed bipolar PDA microchip as a photodetector further evidenced the wavelength dependent optical sensitivity of silicon matrix in the bipolar PDA (Kim et al 2007). Compared to fluorescein (lem=520 nm), alexa fluor 647 (lem=668 nm) provided almost 4-fold higher signal at the identical concentration.…”

“…It was shown in our previous study (Kim et al, 2007) that the photodiode has photoresponse over a wide range of wavelength, from visible to near-IR (400-1,100 nm). The wavelength dependent optical sensitivity is highly influenced by concentration and structure of silicon matrix.…”

“…2.7 Fluorescence detection using the PDA microchip A system as described previously (Song et al 2005;Kim et al 2007) was constructed to investigate optical properties of the PDA microchip as a photodetector. A 454 nm laser beam from a 43 Series Ar-ion laser (Melles Griot, Irvine, CA, USA) was used as the excitation source to excite [Ru(bpy) 3 ] 2+ .…”

“…As part of our continuous effort to lead to higher throughput and speed during biosensing our laboratory developed biosensors based on integrated circuit (IC) microchips with bipolar semiconductor photodiode arrays (PDA) for optical detection (Kim et al 2007;Naoghare et al 2007;Pal and Song 2007;). The miniaturized bipolar semiconductor microchip system integrates photosensors, amplifiers, and logic circuits in a single IC package.…”

Protein Recording Material: Photorecord/Erasable Protein Array Using a UV-Eliminative Linker

“…10,11 Micro-and nanosized arrays prepared by the superior techniques of lithography and patterning are useful for the screening of trace amounts of analytes. 12,13 To produce the array for biosensing, a protein array on a solid surface has the requirement of selective protein interaction [14][15][16] and high spatial resolution.…”