A self-contained fully-enclosed microfluidic cartridge for lab on a chip

Abstract

We describe a self-contained fully-enclosed cartridge for lab-on-a-chip applications where sample and reagents can be applied sequentially as is performed in a heterogeneous immunoassay, or nucleic acid extraction. Both the self-contained and fully-enclosed features of the cartridge are sought to ensure its safe use in the field by unskilled staff. Simplicity in cartridge design and operation is obtained via adopting a valveless concept whereby reagents are stored and used in the form of liquid plugs isolated by air spacers around a fluidic loop. Functional components integrated in the loop include a microfluidic chip specific to the target application, a novel peristaltic pump to displace the liquid plugs, and a pair of removable tubing segments where one is used to introduce biological sample and while the other is to collect eluant. The novel pump is fabricated through soft-lithography technique and works by pinching a planar channel under stainless-steel ball bearings that have been magnetically loaded. The utility of the cartridge is demonstrated for automated extraction and purification of nucleic acids (DNA) from a cell lysate on a battery-operated portable system. The cartridge shown here can be further extended to sample-in-answer-out diagnostic tests.

Simple and inexpensive immunoassay-based diagnostic tests

“…In addition to the disposable cartridge, the device consists of a motor and microcontroller, and it is portable and battery-operated. Feasibility of the technology has been demonstrated by performing nucleic acid purification from a cell lysate [26,27], but the technology is suitable for immunoassay applications, too. Integrated microfluidic systems have been developed to also enable rapid multianalyte detection.…”

“…This creates a peristaltic wave, which transfers the reagents to the lab-on-a-chip situated in the middle. The figure is adapted from the references [26,27] malaria antigen in less than 10 min has been developed. All assay components are dried into a disposable assay cartridge to enhance stability of the reagents in high temperatures.…”

“…While most of the assay chips are very small in size and often based on microfluidics requiring thus only minute volumes of reagents and sample, the instrumentation needed for quantification is still rather large [29,74], or portable desktop devices [26,70,71] and very few handheld systems exist [15,34]. Also, a computer is often needed [74,80], which raises the costs of the device and increases the size of the instrumentation needed.…”

A valve-less microfluidic peristaltic pumping method

“…Some previous reports have demonstrated a pumping mechanism that uses rolling balls to squeeze circular channels embedded in PDMS-chips. 22,23 It makes continuous outflow and is ready for integration into microfluidic devices with reduced dead volume. However, the magnetic-based driving mechanism, rather than direct driving, introduces extra complexity and a) E-mail: yanyi@pku.edu.cn 1932-1058/2015/9(1)/014118/8/$30.00 V C 2015 AIP Publishing LLC 9, 014118-1 reduces stability and robustness of the system.…”

An automated instrument for human STR identification: Design, characterization, and experimental validation

“…However, the method described requires the use of external pumps, valves, and tubing to move the fluids along the chain of processes as well as external power sources for the amplification and detection steps. A recent report employing a self-contained fully enclosed fluidic device [13] describes an ingenious way to integrate miniaturized pumps but does not include an analysis module and requires the eluted sample to be processed externally using gel electrophoresis. We report on the characterization of the instrument and the microfluidic device developed for a ''sample-to-profile'' applicable to the forensic investigation of reference samples.…”