‘Lab on-chip’ is a device that integrates multiple analyses – which are usually done in the laboratory – onto a single chip. The size of the chip usually varies between two and 10 cm. Lab on-chip was initially popular in biomedical applications but its small size attracted the attention of researchers working in different fields. Now this technology is implemented in every branch of science, from physics to chemistry and biology.
Text: Mukesh Yadav
Nowadays the market is filled with miniature devices (like sensors) for various sensing purposes, though these devices are not new. Miniaturization of devices started when the United States was preparing to launch the Apollo program, with billions of dollars spent on miniaturizing the calculator, in order to send those calculators into space. In the early fifties microfabrication was developed, and in the 60s micromechanical structure was developed (called MEMS), something commonly used in airbags and smartphones. After successful implementation of these techniques, the first lab-on chip was created for gas chromatography in 1979 at Stanford University. After this development, scientists began research into the miniaturization of biomedical tests like the polymerase chain reaction (PCR) used to analyse DNA. In its early stages, the lab on-chip technique was confined to the fields of biology and medicine only, but its portability, size, and ability to integrate various steps on a single chip got the attention of researchers and scientists in every field. At present, researchers in the scientific field are trying to implement this technology to reduce the cost of components and increase portability.
Lab on-chip technology is now applied in every field of science. In molecular biology it is used for DNA/RNA amplification and detection, where it increases detection speed whilst maintaining the same sensitivity as a standard laboratory test. It is also used in DNA sequencing, where a chip combines an array of DNA probes to make analysis a thousand times faster (interestingly, the first sequencing of the human genome took hundreds of researchers!). Protein analysis is also done using lab on-chip technology, where all stages of analysis can be conducted on the same chip, shortening the analysis time from several hours to just a few minutes. In physics, the technology is used in the development of miniaturized sensors for use in gas (methane) sensing, for example. These sensors can be sent to remote areas to detect the presence of harmful gases.
Lab on-chip fabrication technology is variable. One of the most common materials used is polymethylsiloxane (PDMS), a transparent and flexible elastomer that is favored because it is very easy and cheap to fabricate. It has one limitation that it absorbs hydrophobic molecules, therefore cannot be used in industrial production. A second fabrication method uses glass that is transparent, compatible, micrometer size and chemical inertia make it a good fabrication method for industries. A final fascinating method is the use of paper (i.e. a paper lab on a chip), something which is not yet applicable but is a concept supported by a famous researcher and one which could make lab on-chip technology accessible to lower income and resource-limited populations.
The advantage of the lab on-chip technology over conventional technologies include its low cost, reduction in human error, compactness, high parallelization (hundreds of analyses at a time) and real time monitoring, etc. Yet still there are challenges in the industrialization of lab on-chip technology, e.g. the fabrication process is not standardized, and the maximum number of biological operations per chip could be further increased, so complete diagnoses can be done using a single chip.
In the near future, lab on-chip implementation may allow for full body diagnoses within a few minutes, with real time monitoring increasing chances of survival and reducing the need for experts.