Microarray chips can be divided into three categories:
1. In-situ synthesis array: in-situ synthesis array is made by chemical synthesis on the solid phase substrate. In the chemical synthesis process, a protective group against photoinstability is combined with the lithography method to perform the operation. In situ synthetic arrays are mainly used for expression analysis, genotyping and sequencing.
2. Point-like array on glass: Point-like array is made of glass slides coated with polylysine. High-density DNA binding is provided through the use of slot pins. It allows the sample to be fluorescently labeled.
3, self-assembly array: This is a fiber optic array made by depositing synthetic DNA on polystyrene microbeads. These microbeads are deposited at the etched end of the array. Different DNA can be synthesized on different microbeads, and when a mixture of microbeads is coated on an optical fiber, a random self-assembling array is formed.