Buffer solutions

Cell culture is the growth of animal or plant cells outside their natural environment. To keep cells growing well, maintain favorable conditions in a suitable artificial environment such as a bioreactor. The following are some variables that ensure optimal cell growth:

• Growth medium to provide essential nutrients
• Growth factors
• Gases like oxygen (O₂) and carbon dioxide (CO₂)
• pH
• Temperature
• Osmotic pressure

Adherent cells need attachment substrates such as tissue culture vessels in lab applications or microcarriers in bioprocessing. Other cells used to produce biological molecules grow in suspension culture.

Successful cell culture and fermentation processes depend on many factors. A key variable in cellular and biological processes is pH. Changes in pH may lead to conformational changes in enzymes or the destruction of proteins. This can cause impaired cell functioning.

Use Cytiva’s broad range of buffer solutions and process liquids to ensure that your cell culture media have the right components to help maintain a stable pH during storage and when added to a cell culture.

Buffers FAQs

Here are some answers to frequently asked questions regarding buffers.

Buffer solutions help cell cultures and liquids to resist changes in their acidic properties. Buffers are comprised of chemicals to maintain a stable pH. When used in cell culture, buffers help resist changes in pH as cells grow and release carbon dioxide and lactate ions. In cell culture media and liquids, biological buffers maintain pH during shipping and storage.

Besides maintaining the pH values in cell culture media and feeds, buffer solutions help regulate the pH and osmotic pressure during cell growth. Because biomanufacturing processes rely on pH as a critical aspect, buffers help ensure consistent results.

Biological buffers consist of a mixture of a conjugate acid (proton donor) and base pair. Buffers easily release or take up hydrogen ions, which allows them to control the hydrogen ion concentration. A buffer works via reversible reactions, where the proton acceptor (base) accepts hydrogen ions as the H+ concentration increases, and the proton donor releases hydrogen ions as the H⁺ concentration decreases.

Buffers come in either liquid or powdered formulations with varying pKa values. Common types of buffers include:

• HEPES – has negligible metal ion binding and is often used to buffer mammalian cells in open systems
• MOPS – is used for bacteria, yeast, and mammalian media and in electrophoresis
• Tris HCI – is a common buffer in electrophoresis
• DPBS – Dulbecco’s phosphate-buffered saline, is often used in mammalian cell culture
• Sodium bicarbonate – helps to resist changes to pH when cells give off carbon dioxide