This document describes a new low-cost, miniaturized UV photosensor that can directly measure DNA concentration within a closed tube. The sensor uses photodiodes fabricated in silicon-on-insulator (SOI) technology to detect the absorbance of UV light by DNA solutions. Testing showed the photodiode current is inversely proportional to DNA concentration over a wide range. This new sensor allows direct measurement of DNA concentration without manipulating or wasting samples, and compares favorably to existing methods. Its originalities include using an SOI photosensor and enabling low-cost, portable, and adaptable concentration measurements within closed tubes.

1. Low-cost miniaturized UV photosensor for direct measurement of DNA
concentration within a closed tube container| ISweek - Industry sourcing
Highly sensitive measurement of DNA concentration on portable, easy-to-use, low-cost
miniaturized equipments without sample waste is challenging.
The DNA peak optical absorbance at λ=260 nm is a well-known property already used in
the spectrometric measurement of DNA concentration. Existing apparatus are large-
sized, expensive and require a manipulation of DNA. In the current work, a low-power,
suitable and miniaturized photosensor aiming at a sensitive and direct measurement of
DNA concentration has been designed. Direct measurement, i.e. without sample
manipulation, implies UV transmission through the translucid tube wall from the closed
tube containing the DNA sample in solution.
To allow measurements at such low wavelengths, we designed and fabricated
photodiodes in SOI technology to ensure a high responsivity in the UV range.
Measurements of the photodevice confirmed its responsivity spectrum and magnitudes.
These fully integrable photodiodes, fabricated in SOI CMOS technology, can be coupled
to a complete signal processing microsystem.
Direct measurements at 280 nm optical wavelength of serially diluted DNA within a
closed tube (range: 40 pg/μL to 400 ng/μL in a volume of 45 μL) generated a monotonic
relation between the DNA concentration and the mean of the diode photocurrent induced
by light transmission through DNA solution and tube container. Absorbance of the
incident UV ray was inversely proportional to DNA concentration. The photosensor
compared favorably with other DNA quantitative methods (spectrophotometry,
fluorometry, real-time PCR) in terms of sensitivity.
Originalities of this work are the use of a thin-film SOI photosensor, the low-cost, portable
and adaptable system and the potential of the device for direct measurement of nucleic
acid concentration within tube containers without sample manipulation or waste.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products