Types and Uses of Serological Pipettes

The serological pipette is a laboratory instrument that transfers liquids measured in volume by ml. Most have graduations on the side for measuring the liquid being dispensed or aspirated. An important step when culturing or plating cells is the even distribution throughout a solution.

The use of serological pipettes is an efficient and gentle means of mixing cell suspensions. They can also be used for mixing reagents and chemical solutions. After treatment or isolation of experimental cell cultures, serological pipettes are useful in transferring colonies of cells for further empirical analysis or expansion.

They are also used for carefully layering reagents for creating density gradients such as a ficolin gradient used to purify blood plasma cells.

Serological pipettes are available in many options and sizes. Next Day Science has four varieties of disposable serological pipettes. The calibrated pipettes deliver volumes that range from 0.1 ml to 25 ml. The most common sizes are 5, 10, and 25 ml.

They are used for liquid transfers that are free from pathogenic microorganisms. For tissue culture and microbiology experiments, Next Day Science has pre-sterilized transfer pipettes that can be heat sealed to store airtight samples.

Common uses for Next Day Science pipettes are:

• Urinalysis
• Immunology
• Hematology
• Blood Banking

They are excellent for applications involving tissue cultures. The low-affinity surfaces reduce sample, protein, or cell loss. These pipettes come in ten designs. It is highly likely that one of them will meet requirements for a number of drops per ml, pipette capacity, bulb draw, or length.

Plastic pipettes can be used for biosafety level on (BSL-1) laboratory experiments. Plastic pipettes are the only type suitable for BSL-2 organisms where Bunsen burners cannot be used. They are also recommended for applications that involve fluid agar transfer.

How are liquids aspirated and dispensed from serological pipettes?

A pipettor dispenser¹ is needed for fluid transfers. The dispensers negate an ancient technique used by researchers called mouth pipetting. Transferring liquids with this primitive method is not recommended. Serious side effects can result from fluid entering the mouth.

Either a pipette bulb or pump is used for aspiration and dispensing. The bulb is the least accurate. It is used to transfer non-specific liquid amounts. The pump is more precise. It allows more accurate regulation of the fluid, particularly when dispensing repeat liquid volume solutions. There are two triggers on the pump. One is depressed for aspiration, the other for dispensing.

What are the four types of serological pipettes offered by Next Day Science?

The disposable serological pipettes provided by Next Day Science are medical grade crystal clear polystyrene pipettes that have been sterilized by gamma irradiation. The sterilization process guarantees the pipettes are Pyrogen and DNase/RNase free.

The four categories offered by Next Day Science are labelled:

• Pasteur Pipettes
• Serological Pipettes
• Transfer Pipettes
• Serological Pipettes, Steril, Individually Wrapped

The item number for the Pasteur Pipettes is # B4 Series. They are medical grade transparent pipettes suitable for drawing, blending, and transferring a particular volume of liquid. They offer chemical stability. The clear gradients are excellently transparent for easy observation. Fluid is easy to control.

The tenacious pipettes can be bent at an angle for special-shaped containers and micro vessels. The individually wrapped pipettes are highly precise and offer drop repeatability. Ethylene Oxide is used to sterilize the pipettes.

The Serological Pipettes (Item # A10 Series) are used in tissue and bacterial culture experiments. They have an edged color-coded band that is used for identification. The serological pipettes have a bonded filter made of polyolefin fibre to reduce contamination and negative graduations for extra volume.

Transfer Pipettes (Item # P4000 Series) are unbreakable one-piece pipettes that eliminate exposure to infectious materials, broken glass, and contaminated rubber bulbs. The Serological Pipettes, Sterile, Individually Wrapped (Item #32-000 Series) utilize a unique filter plug that prevents overfilling.

The permanent graduations are sharp, black intervals that guarantee precise readings. Reverse graduations show the volume removed when dispensed. They are available in various quantities and sizes and fit the major brand pipettors.

¹JoVE Science Education Database. General Laboratory Techniques. Introduction to Serological Pipettes and Pipettors. JoVE, Cambridge, MA, (2017).