How does Biochip Array Technology work?

The core technology is the Randox biochip onto which multiple competitive immunoassays are carried out, giving results for multiple drug assays simultaneously. Competitive immunoassays are employed for the Drugs of Abuse arrays where drug in the specimen and drug labelled with horse radish peroxidise (HRP) directly compete for anti-boding binding sites.The biochip detection system is based on a chemiluminescent signal. This is essentially the emission of light, without heat, as a result of a chemical reaction.

An enzyme is used to catalyse the chemical reaction on the biochip and generate the chemiluminescent signal. Increased levels of drugs in a specimen leads to reduced binding of drug-labelled HRP and thus a reduction in chemiluminescent signal. The light emitted from the chemiluminescent reaction that takes place is detected and compared to that from a calibration curve using a Charge Coupled Device (CCD) Camera. This CCD Camera simultaneously records the light emission from all the discrete test sites on each biochip on the carrier.

Unique imaging software on the analysers is used to translate the light signal into an analyte concentration. The CCD Camera is made up of a collection of light sensitive diodes which convert light into electrons to produce an electrical charge. The brighter the light that hits a single diode, the greater the electrical charge that will accumulate at that site.

The degree of light emission can therefore be quantified based on the strength of the electrical signal generated. A validated biochip image is then produced, which undergoes image analysis for quantification of the signal output at each DTR. A validated calibration curve is used to determine the concentration of each analyte.