Biplob Dey presents on DNA microarray technique. A DNA microarray is a collection of DNA spots attached to a solid surface, with each known gene occupying a particular spot. Fluorescently labeled target sequences that bind to probe sequences generate a signal, showing levels of gene activity. DNA microarrays allow samples to be labeled with fluorescent dyes and hybridized to a chip to detect complementary nucleic acid sequences through hydrogen bonding and measure gene expression patterns. There are different types of microarrays including spotted DNA arrays and oligonucleotide arrays. Applications include detecting cancer cells and studying antibiotic activity.

1. Presenting By-
Biplob Dey
M.Pharm (Pharmacology)
1st Semester
DNA Micro Array Technique

2.  A DNA microarray (also commonly known as DNA Chip or biochip) is a collection
of microscopic DNA spots attached to a solid surface.
 Each known gene or “probe” occupies a particular “spot” on the chip, and
varying levels of fluorescent activity show varying levels of gene activity in
introduced genetic material .
 Fluorescently labeled target sequences that bind to a probe sequence
generate a signal.
Introduction

3. • The concept of DNA microarrays began in the mid 1980s.
•“Quantitative Monitoring of Gene Expression Patterns with a complementary DNA
microarray” reported by Patrick Brown, Mark Schena and colleagues in Science (1995).
• Steve Fodor developed scanner for reading the output.
• Mark schena was proclaimed as the “Father of Microarray Technology”.
Historical Background:

4.  The core principle behind microarrays is hybridization.
 Samples are labelled using fluorescent dyes.
 At least two samples are hybridized to chip.
 Complementary nucleic acid sequences get pair via hydrogen bonds.
 Washing off of non-specific bonding sequences .

6. How microarray chip is made:
Two main agent-
1. Blockers
2. Masks
1.Blockers added to all boxes.
2.Addition of Masks
3.Addition of Nucleotides
4.New Mask
5.Blockers remove

7. Spotted DNA arrays (“cDNA arrays”)
• Developed by Pat Brown (Stanford)
• PCR products (or long oligos) from known genes (~100 nt) spotted on glass, plastic,
or nylon support.
Gene Chips:
 Oligonucleotide arrays (Affymetrix)
• Small number of 20-25 mers/gene
 Ink-jet microarrays (Agilent)
• Large number of 25-60mers “printed” directly on glass
• Four cartridges: A, C, G, and T
• Flexible, rapid, but expensive
Types of Microarrays:

9. Application:
1. In detecting Cancer cells.
2. In Antibiotic