Micro fluorescent analysis system integrating GaN-light-emitting-diode on a silicon platform

Abstract

A micro fluorescent analysis system is proposed using silicon micromachining. GaN blue light-emitting diode (LED) monolithically integrated on a silicon substrate is used as a light source for the fluorescent analysis system. The blue light suits the excitation of several dyes used commonly in fluorescent analysis. Silicon photodiode (Si-PD) that matches the visible and near infrared fluorescent wavelengths of dyes is integrated on a silicon substrate. Polydimethylsiloxane (PDMS) micro-channels are also stacked for flowing dye-sensitized liquid. Therefore, the proposed system is an integrated system that can be composed on a silicon platform, i.e. a bottom layer of Si-PD, a middle layer of GaN-LED on silicon substrate and a top layer of micro PDMS channel. An aperture is opened into the GaN-LED layer by deep reactive ion etching to create a ring-shaped GaN-LED and a through-hole for detection. The light from the ring-shaped GaN-LED in the middle layer excites the dye-sensitized liquid in the top micro-channel layer. The fluorescence emitted from dye is detected by the Si-PD on the bottom layer at an angle larger than 90 degrees from the direction of excitation. Therefore, the detection optics consist basically of a dark-field illumination optical system. In order to evaluate the performance of the integrated system, fluorescence of fluorescein isothiocyanate (FITC) solution flowing in the micro channel is measured. From the measurement, the noise, sensitivity and limit of detection in the fabricated system are evaluated for FITC dye to be 0.57 pA, 1.21 pA μM(-1) and 469 nM, respectively. From these results, a compact fluorescence analysis system is demonstrated.

From Nanosecond Photochemistry to Optical Force Chemistry: My Journey

“…Indeed, these results were introduced as optical trapping‐based microchemistry by Ashkin [52] . In parallel with our approach, microchemistry research has been developed also in organic photochemistry and analytical chemistry, where microchannels and microfluidics are coupled with light emitting diode (LED) [53,54] …”

“…[52] In parallel with our approach, microchemistry research has been developed also in organic photochemistry and analytical chemistry, where microchannels and microfluidics are coupled with light emitting diode (LED). [53,54] Laser trapping of micrometer-sized targets are interpreted by Mie theory and geometrical optics, optical force exerted on nanometer-sized is understood in the framework of light scattering theory and point dipole approximation. [55] It consists of scattering and gradient forces and, in case that the latter is stronger than that of the former, optical trapping is realized.…”

Micro Total Analysis Systems: Fundamental Advances and Applications in the Laboratory, Clinic, and Field

“…9 Another compact device monolithically integrated a gallium nitride blue light emitting diode (LED) on a silicon substrate which served as a light source for the fluorescence analysis system. 10 The integration of these micro-optical elements on-chip can reduce cost and enhance portability.…”

“…A multiple internal reflection photonic lab-on-a-chip for cell analysis integrated biconvex microlenses, self-alignment microchannels, and air mirrors . Another compact device monolithically integrated a gallium nitride blue light emitting diode (LED) on a silicon substrate which served as a light source for the fluorescence analysis system . The integration of these micro-optical elements on-chip can reduce cost and enhance portability.…”

Membrane Light‐Emitting Diode Flow Sensor

“…Illumination, sensing, and modulation are desirable properties of the III‐nitride‐based light‐emitting diode (LED) for wide‐ranging applications . Integrating them together is promising for the development of multifunctional optoelectronic devices, which may have a wide variety of applications for the Internet of things (IoT), wherein many of the objects that surround us will be sensed and the information transmitted through the Internet . It is known that the self‐heating effect degrades the efficiency of the LED performance .…”