An introduction to the use of biochips

We’re going to deviate against the usual discussions about nanomaterials in this article to talk about biochips. Biochips are a type of miniaturised laboratory that is composed of a series of microarrays. These microarrays act as test sites within the biochip, and because many can be fabricated within a biochip, it enables many tests to be performed simultaneously. This naturally translates to a much higher test speed and output compared to if every test had to performed individually using other methods.

Biochips have been around for a long time in one form or another, but the systems that are available nowadays are significantly more complex than they have ever been—and can easily contain over 1000 components (mainly due to the electronics in the biochips). There are three main types of biochip that are used, and these include Lab-on-a-chip, DNA chips and protein chips.

There are four main components to any biochip (simple or complex). The first is the microarray. The microarray is essentially a network of biosensors that are fabricated to detect various biomolecules. These microarrays are fabricated by depositing the sensing molecules onto a flat surface and physically bonding them to the surface, whereupon they are integrated with microelectronics. Whilst this is the critical part of biochips, a transducer is also required to translate the molecular sensing mechanism, be it through the interaction of intermolecular forces or via a reaction, into a useable output. This brings us to the third and fourth basic components, which are the signal processing unit and the readable output, which correlates the data and puts it into a form that can be read and used by the operator.

Who’s in the Biochip Space?

Many will be wondering who’s actively involved in the biochip space. The biggest company in the world of biochips and microfluidic assays is Illumina, who have a wide range of biochip and microarray solutions for various biomolecule sensing applications. But, whilst they are by far the biggest company who produces and supplies biochips, they are also present in many other sequencing and assay-based areas as well. Affymetrix used to also be a big company in the biochip space before they were taken over by ThermoFischer Scientific.

Two other big companies in the biochip space, who have a lot of products out in the market include SynVivo and EUROIMMUN. SynVivo are a producer of biochips who offer a tailored approach to their customers by providing a custom assay kit for use on their chip designs. SynVivo also have four standard types of networks and channels that can be implemented, but state that they can fabricate almost any required design. EUROIMMUN, on the other hand, produce biochips, but rather than specialising in biochips, it is a company that covers many biomolecular sensing techniques. For EUROIMMUN, their biochips are mainly tailored to the detection of antibodies and infectious diseases (viruses, fungi, parasites etc).

An interesting company which has found its own niche is Diagnostic Biochips. This company is different to many other biochip manufacturers because they focus on biochips that can be implanted under skin and are focused on neurosensing solutions; with neural activity monitoring, continuous real-time chemical sensing and closed-loop therapy applications being the prime foci.

Applications of Biochips

Biochips applications are widespread across the fields of biochemistry, microbiology, pharmacogenemics, proteology, clinical pathology and DNA analysis. In terms of specific applications—although this is not an exhaustive list—biochips can be used to screen analytes to see if they contain any traces of biological warfare agents, as well as in drug discovery and drug development processes, molecular diagnostic processes for cancer and other diseases, personalised medicines, and for generally detecting and identifying a wide range of biomolecules in a sample—including, but not limited to, DNA, RNA, antibodies and antigens, enzymes, bacteria, fungi and viruses. Biochips have also found some use in skin-on-a-chip applications.

Written by Liam Critchley