A biochip is a miniaturized microfluidic
device similar to the electronic microchip that brought in the digital age. It consists of tiny microfluidic channels, pumps and valves that transport small amounts of sample fluids to biosensors that can perform a variety of tests on those fluids in near real time. In short, it is a cheap and reliable computer chip look-alike that performs thousands of biological reactions.
Advantages of biochip
small, lightweight, requiring less sample fluids and
reagents and being more sensitive and efficient than larger current devices.
1) Space applications: Acts as smaller, more robust devices
for analyzing blood, saliva and urine and for testing water and food supplies for the contamination by micro-organisms.
2)DNA hybridization on solid surfaces in which short single strands of DNA (oligos), are bonded to a solid substrate like glass, and then fluid containing unknown DNA flows over it.
3)identification of microorganisms from their unique genetic signature:The basic principle used here would be to deposit an array of oligo spots that uniquely identify the organisms and then using surface hybridisation to see if anything matches the unknown DNA.
4) the Affymetrix GeneChip: for the detection of mutations in specific genes as diagnostic "markers" of the onset of a particular disease.Here,the patient donates test tissue that is processed on the array to detect disease-related mutations.
5) detect the differences in gene expression levels in cells that are diseased and the healthy ones. This provides drug makers with unique targets that are present only in diseased cells.
6) some companies are trying to create equivalent of a wet laboratory on a chip.Eg: Caliper's LabChip, which uses microfluidics technology to manipulate minute volumes of liquids on chips.
The concept of a biochip wasdeveloped by Fred Sanger and Walter Gilber through DNA sequencing approach.The basis for considering miniaturizing molecular assays was laid by DNA sequencing chemistry, electric current,and micropore agarose gels. polymerase chain reaction (PCR) invented by Kary Mullis allowed us to amplify minute amounts of DNA to quantities where it could be detected by laboratory methods. fluorescence-based DNA sequencing,allowed the automation of reading DNA sequence.
Standardisation is a challenge to biochip industry. Both the assays and the ancillary instrumentation need to be interfaced so that the data can be easily integrated into existing equipment.
flame hydrolysis deposition (FHD) can produce microstructures that can be readily incorporated onto a chip .Biochips are also continuing to evolve as a collection of assays that provide a technology platform. protein-based biochips could be used to array protein substrates that could then be used for drug-lead screening or diagnostic tests.
More info in this link: