Petri Dish

A Petri dish is essentially a shallow cylindrical dish, typically made using glass or transparent plastic. A Petri dish has a flat bottom with vertical sides. The lid of the Petri Dish is slightly larger for effectively fitting over the sides. The lid allows the petri dish from getting contaminated. While the Glass Petri dishes can be re-used again and again after sterilization, Plastic Petri dishes are mostly disposed after of after single use.

Petri Dish is a crucial piece of tool in a microbiology lab. Agar plates, a type of Petri Dish that is filled with Agar is frequently used. The Petri dish after solidification with agar and other constituents is added with microbe-laden sample for bacterial growth. However in cell culture there is no need for adding agar to Petri dishes.

Modern Petri dishes often comes with innovative designs for facilitating easy stacking and handling. Petri Dishes with rings on the lids and bases allows a proper stacking so as to prevent sliding off one another. There are some variations of Petri Dishes used for numerous applications. Multiple Petri Dishes when incorporated into a single plastic container is termed as a "multi-well plate". A microtiter plate is also basically a highly modified multiwell Petri dish.

Types of Petri Dish

• Plastic Petri Dish
• Glass Petri Dish
• Disposable Petri Dish

Major Applications of Petri Dish
The primary function of a Petri Dish lies with biologists who uses it for culturing cells. Significant breakthroughs in science like growing of cells that is integrated with electronic circuits, cloning of organs and understanding viruses all have been made easy by using the modest petri dish. Some of the other functions of Petri Dish includes.

• Observing of plant seed germination, as the clear dish makes it possible for the students in a bio lab to observe every step of growth
• Observing the behaviour of small animals
• The Petri dish also finds use in a dissection process as it is appropriately sized for placing under a microscope
• A Petri dish is used for basic experiments that requires transportation of liquids in sterile containers or drying of fluids

Related Products
Petri Dish Rack
A Petri Dish rack is used for neat and safe holding of Petri dishes. Generally plastic material like rugged ABS or acrylic is popular but Steel wire Peri Dish racks are also used.

Petri Dish Liner
Petri Dish Liners are required for a contamination-free cell culture application. Generally Petri Dish liners are made using teflon films. Some of the features of teflon made Petri Dish liner includes the following.

• The liner is chemically inert and noncontaminating
• Liner can be autoclaved
• Cells can be easily cultured as the surface is nonstickable
• Surface is non-wettable

The History Behind the Petri Dish
Generally it is seen that in case of scientific inventions technicians who work for the development of a particular product generally remains invisible, overshadowed by their more illustrious superiors. However Petri Dish is an exception. Julius Richard Petri(1852-1921) worked as an assistant to Robert Koch.

Robert Koch (1843-1910) was the master of "germ theory”. Though Koch's work is remembered, (strangely though his name does not figure out beyond the world of microbiologists) but Koch's assistant Julius Richard Petri became immortal though only a few amongst us know who exactly he was.

Let's now understand the circumstances that led to the invention of Petri Dish. Bacteria at that time were grown in liquid broth. Robert Koch after doing extensive research came out with the idea that it is better to culture bacteria on a solid medium instead. By using a solid surface pure colonies of bacteria could be easily isolated and effect of each bacteria could be studied in great detail.

Koch employed a "puddle" of gelatin on a flat glass surface. Later on he used a flat bottle with the gelatin spread on the sides. The access was through a narrow opening at the end. Petri who was working under Robert Koch devised a better method. He concluded if gelatin is poured in a shallow dish and covered it would be easier in getting the bacterial cultures. The plan succeeded wonderfully and the rest as well know is history as Petri is a household name now.

The story is not yet complete a Slavonian scientist called Emanuel Klein (1844-1925) may also have invented something that was very close to a Petri Dish slightly earlier than Mr. Petri. Emanuel Klein who conducted his research in England wrote a textbook titled Micro-organisms and Disease. In 1885 the book's third edition contained a description of a dish that was almost similar to the one that Mr. Petri was supposed to have invented.