Hybrid optofluidic integration

Abstract

Complete integration of microfluidic and optical functions in a single lab-on-chip device is one goal of optofluidics. Here, we demonstrate the hybrid integration of a PDMS-based fluid handling layer with a silicon-based optical detection layer in a single optofluidic system. The optical layer consists of a liquid-core antiresonant reflecting optical waveguide (ARROW) chip that is capable of single particle detection and interfacing with optical fiber. Integrated devices are reconfigurable and able to sustain high pressures despite the small dimensions of the liquid-core waveguide channels. We show the combination of salient sample preparation capabilities—particle mixing, distribution, and filtering—with single particle fluorescence detection. Specifically, we demonstrate fluorescent labelling of λ-DNA, followed by flow-based single-molecule detection on a single device. This points the way towards amplification-free detection of nucleic acids with low-complexity biological sample preparation on a chip.

Single-Virus Analysis Through Chip-Based Optical Detection

“…The planar optical layout based on intersecting solidcore and target-carrying liquid-core waveguides leaves the third dimension open for vertical integration of other functionalities. Specifically, this enables connection of a microfluidic sample processing layer made and optimized using traditional microfluidic device materials such as PDMS and glass as opposed to a silicon substrate that is preferable for the sensing section of the device [14,15]. Using such a hybrid approach, numerous key components of sample processing have been implemented.…”

Integration of programmable microfluidics and on-chip fluorescence detection for biosensing applications

“…33 These optofluidic devices have been shown to provide single biomolecule fluorescence sensitivity. 19,24,33 Recent correlated optical and electrical detection of single nanospheres and virus particles has proven the single particle nature of ARROW chip detection. 34 The planarity of the ARROW chip allows for easy vertical integration of microfluidic processors, a scenario that still allows for the detection of single nucleic acids.…”

“…34 The planarity of the ARROW chip allows for easy vertical integration of microfluidic processors, a scenario that still allows for the detection of single nucleic acids. 19 The present device was created by depositing alternating dielectric layers of silicon dioxide (SiO 2 , refractive index n ¼ 1.47) and tantalum oxide (n ¼ 2.107) on a silicon wafer to ensure optical guiding in the low-index liquid core. The thicknesses of the cladding layers, starting with SiO 2 in order of deposition, were 265/102/265/102/265/102 nm, designed for broadband low-loss transmission between 400 and 800 nm.…”

“…The optofluidic chip, on the other hand, is able to detect fluorescence from single biomolecules. 19,23,24 We demonstrate the functional integration of the microfluidic automaton with an optofluidic chip and the implementation of sample preparation steps required for nucleic acid analysis used in genomic studies and disease detection based on single particle fluorescence detection in flow. Specifically, we show on-chip mixing of multiple fluorescent agents as well as sequence-specific solid-phase extraction and detection of synthetic viral nucleic acid targets.…”

“…Recently, hybrid systems combining PDMS (polydimethylsiloxane)-based microfluidic layers with a liquid-core waveguide optical detection layer have been reported. 19,20 Optofluidic chips based on antiresonant reflecting optical waveguides (ARROWs) are ideal for such integration due to their high fluorescence sensitivity and planar optical layout. These devices are based on a series of alternating dielectric layers that allow for interference based guidance of leaky modes in low refractive index, liquid-core waveguides.…”