Does your serum contain tetracycline?

Written by admin on February 26, 2013. Posted in Knowledgebase

We do not add this antibiotic to serum during manufacturing. Tetracycline is an antibiotic which is often used to treat animals prior to slaughter. Although there should be sufficient time between the last dose of antibiotic and slaughter for the drug to metabolize, this is not always the case and the serum may contain residual amounts of tetracycline.

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How long can frozen human serum be stored?

Written by admin on February 26, 2013. Posted in Knowledgebase

Although it is impossible to claim stability data for every possible application and use for human serum AB, we conservatively estimate that if this product is stored properly at -20ºC, it can be used for 5 years from the date of manufacture without any decrease in product performance. Storage at any other temperature may affect results.

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Innovative Research Products go to great lengths to ensure that our human sera are the most consistent products commercially available. Although our human serum is manufactured using raw material from congruous donor pools and according to time-tested protocols, it is possible to perceive differences in the physical appearance of this product from lot-to-lot. This phenomenon can be largely attributed to variation in diet amongst human beings (particularly with respect to dietary fats). Another source for slight differences comes from non-uniform storage conditions and/or handling variations in the laboratory setting. Due to the special sensitivity of this product (as compared to other sera), it is critical that human serum be cared for as recommended by the manufacturer.

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Due to a diet higher in fats and oils, human serum typically contains higher levels of lipids than serum from other sources. Even after sterile filtration through 0.1mm filters, particles remain suspended in solution that can aggregate and precipitate as a result of subsequent freezing, thawing and/or heat-inactivation. It is for this reason that we suggest minimizing such temperature changes. The presence of particulate matter does not indicate contamination of any sort, and does not negatively impact the serum's performance.

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Off-the-clot serum is collected from blood that is allowed to coagulate naturally after collection. It has not been exposed to any anticoagulants. Plasma-derived serum is produced by defibrinating pooled human plasma collected in the presence of an anticoagulant, such as sodium citrate. Plasma-derived serum, such as the human serum AB , is generally more economical and consistent than off-the-clot product. Off-the-clot serum is, however, available in original transfer packs from individual donors, a feature attractive for certain metabolic studies.

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Why use human serum?

Written by admin on February 26, 2013. Posted in Knowledgebase

Human serum yields superior results when culturing many types of human cells, particularly those associated with the human immune system. Human serum is used to supplement lymphocyte culture media, as a blocking agent for immunohistochemical staining procedures, and as a negative control in human leukocyte antigen (HLA) tissue-typing applications.

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What do you know about endotoxin?

Written by admin on February 26, 2013. Posted in Knowledgebase

Cell culture contamination has been a major concern for researchers since cell culture was introduced in the early 1900's. One particular villain to the field of in vitro research has been endotoxin. But what do we really know about it?

What Is Endotoxin?

Endotoxin is a complex lipopolysaccharide (LPS), a toxic substance found in the outer membrane of most gram-negative bacteria. For example, one E. coli cell can contain up to 2 million LPS molecules. The bacteria releases the endotoxin into the culture environment while growing and when dying, possibly affecting the culture.

Studies of endotoxin in vitro have shown that they may affect the growth or performance of cultures and are a major source of experimental variation, although endotoxin does not affect all cells equally. Old cell lines that have been grown in culture for many years may have developed a resistance from long-term exposure before testing was common practice. CHO, 3T3, WI-38 and HeLa, for example.

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FBS & Global Biological Risk

Written by admin on February 26, 2013. Posted in Knowledgebase

You may be familiar with the terms "traceability" and "origin" in reference to fetal bovine serum (FBS), but how do these topics really impact the use of serum in cell culture? "Origin" is simply the country in which the raw material was collected. "Traceability" refers to the documentation roadmap that connects serum origin to final manufacturing and distribution.

So, Why Is Origin Important?

As viral patterns shift around the globe, the supply and quality of bovine products such as FBS are affected. One of the most recent issues to alter the global supply-and- demand dynamic is Bovine Spongiform Encephalopathy (BSE), more commonly known as "mad cow disease." BSE is a chronic, degenerative disease affecting the central nervous system of cattle. The United States Department of Agriculture (USDA) only permits the importation of bovine products from those countries that are considered to be at low risk for BSE. The spread of BSE, therefore, limits the global supply of FBS, driving up demand for serum from the low-risk countries and linking FBS prices to perceived BSE risk; the lower the BSE risk, the higher the cost of serum.
FBS & Global Biological Risk

Where Is The Risk?

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BSA: Cohn Cold EtOH vs. Heat-Shock

Written by admin on February 26, 2013. Posted in Knowledgebase

Albumin is one of the most extensively used proteins in biological research today. It acts as a powerful antioxidant in cell culture. It binds, sequesters and stabilizes a variety of molecular species which are often unstable. This acidic, soluble protein has both high- affinity and secondary binding sites, optimizing the roles that fatty acids, metals, disulfides, and other molecules play in cellular metabolism.

With all of the choices for bovine serum albumin (BSA) available, you may be wondering what the differences are and which product is right for your application.

How Is BSA Made?

BSA is separated from whole blood using a multi-step fractionation process. Dr. Edwin J. Cohn, a researcher at Harvard University, developed the original process in the 1940's.

Dr. Cohn found that the blood proteins could be separated from each other by manipulating the temperature and varying concentrations of an organic solvent. His process used these two variables to separate human blood plasma into five fractions, of which the fifth contains mostly albumin. This is why it was called "Fraction V".

Today there are two alternative processes used to extract albumin from plasma; they are Cohn's cold-ethanol process and a heat- shock process.

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What is USDA Serum?

Written by admin on February 26, 2013. Posted in Knowledgebase

Labels may not always tell the truth. Some labels offer little useful information about the product in the bottle, while some may even seek to mislead a buyer into believing something untrue about that product.

Labels that can mislead a buyer are not limited to one industry or geographic region. This topic generated heated global debate between consumers and food companies over claims such as "fresh" or "organic;" label disputed arise between unions and durable goods manufacturers over claims of "Made in the USA," when parts may originate in China; and, the most dubious labeling practices in the world of fetal bovine serum relate to misleading references involving the United States Department of Agriculture (USDA) and this agency's role in serum sourcing and supply safety.

Many Faces Of The USDA

Depending upon the vendor, fetal bovine serum is currently sold under a variety of label claims that invoke the USDA acronym. Surely you've seen the following:

  • USDA Tested
  • USDA Approved
  • Standard Certified Premium Origin FBS Grade
  • Fetal Bovine Serum & USDA (Mis)labeling

What Do These Tag-Phrases Really Mean?

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What is Heat Inactivation?

Written by admin on February 26, 2013. Posted in Knowledgebase

The practice of heat inactivating serum was originally developed when only serum from adult animals was available for cell culture. Adult serum contains various immune factors, particularly serum complement, which may inhibit or destroy cells under certain conditions.

Heating serum is intended to inactivate serum complement. Today, serum is often heat- inactivated without any evidence of beneficial effect, simply because an earlier protocol calls for such action. However, certain applications demand the inactivation of complement; e.g., it is often required to preserve the integrity of immunoassays.
Heat inactivation will increase precipitates and consequent turbidity in the serum.
Innovative will provide heat inactivation for most sera upon request, as a service to our customers. Should you prefer to perform this step in house, we recommend the following protocol:

Recommended Protocol:

  1. Thoroughly thaw serum and swirl to homogenize.
  2. Prepare a control bottle containing water. The control bottle should be stored along with the serum bottles to assure identical initial temperatures. This control bottle will be used to monitor the temperature and

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Biosafety Levels

Written by admin on May 9, 2014. Posted in Knowledgebase

The regulations and recommendations for biosafety in the United States are contained in the document Biosafety in Microbiological and Biomedical Laboratories, prepared by the Centers for Disease Control (CDC) and the National Institutes of Health (NIH), and published by the U.S. Department of Health and Human Services. The document defines four ascending levels of containment, referred to as biosafety levels 1 through 4, and describes the microbiological practices, safety equipment, and facility safeguards for the corresponding level of risk associated with handling a particular agent.

Biosafety Level 1 (BSL-1): BSL-1 is the basic level of protection common to most research and clinical laboratories, and is appropriate for agents that are not known to cause disease in normal, healthy humans.

Biosafety Level 3 (BSL-3): BSL-3 is appropriate for indigenous or exotic agents with a known potential for aerosol transmission, and for agents that may cause serious and potentially lethal infections.

Biosafety Level 2 (BSL-2): BSL-2 is appropriate for moderate-risk agents known to cause human disease of varying severity by ingestion or through percutaneous or mucous membrane exposure. Most cell culture labs should be at least BSL-2, but the exact requirements depend upon the cell line used and the type of work conducted

Biosafety Level 4 (BSL-4): BSL-4 is appropriate for exotic agents that pose a high individual risk of life-threatening disease by infectious aerosols and for which no treatment is available. These agents are restricted to high containment laboratories.

  • For more information about the biosafety level guidelines, refer to Biosafety in Microbiological and Biomedical Laboratories, 5th Edition, which is available for downloading at

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Guidelines for Safe Laboratory Practices

Written by admin on July 22, 2014. Posted in Knowledgebase

The following recommendations are simply guidelines for safe laboratory practices, and they should not be interpreted as a complete code of practice. Consult your institution's safety committee and follow local rules and regulations pertaining to laboratory safety.

  • For more information on standard microbiological practices and for specific biosafety level guidelines, refer to Biosafety in Microbiological and Biomedical Laboratories, 5th Edition at


  • Always wear appropriate personal protective equipment. Change gloves when contaminated, and dispose of used gloves with other contaminated laboratory waste.

  • Wash your hands after working with potentially hazardous materials and before leaving the laboratory.

  • Do not eat, drink, smoke, handle contact lenses, apply cosmetics, or store food for human consumption in the laboratory.

  • Follow the institutional policies regarding safe handling of sharps (i.e., needles, scalpels, pipettes, and broken glassware).

  • Take care to minimize the creation of aerosols and/or splashes.

  • Decontaminate all work surfaces before and after your experiments, and immediately after any spill or splash of potentially infectious material with an appropriate disinfectant. Clean laboratory equipment routinely, even if it is not contaminated.

  • Decontaminate all potentially infectious materials before disposal.

  • Report any incidents that may result in exposure to infectious materials to appropriate personnel (e.g., laboratory supervisor, safety officer).

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Animal Use Serum

Written by admin on February 26, 2013. Posted in Knowledgebase

Animal serum is an excellent source of nutrients for cells in culture because it contains proteins, lipids, salts, vitamins, minerals, amino acids and other components necessary for growth. When stored and handled correctly, the performance characteristics of serum can be maintained for many years. Improperly storing and/or thawing serum products can decrease not only the immediate and long-term stability, but also their effectiveness. Growth promotion data demonstrate that serum maintains its growth characteristics throughout its shelf life if stored correctly.

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Serum Stoarge

Written by admin on February 26, 2013. Posted in Knowledgebase

To effectively preserve the integrity of animal serum, it should be stored frozen and protected from light. The recommended storage temperature is -10 to -40 °C. At temperatures below -40 °C, the bottles may become brittle resulting in an increased risk of breakage.Multiple thaw/freeze cycles should be avoided as they will hasten the degradation of serum nutrients and can induce the formation of insoluble precipitates. For this reason, serum should never be stored in "frost-free" freezers. These appliances occasionally warm themselves to avoid internal ice deposits and are detrimental to the clarity and stability of frozen serum products

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Thawing Procedure

Written by admin on February 26, 2013. Posted in Knowledgebase

Below is the recommended thawing procedure for frozen serum. This thawing procedure can be used for frozen plasma as well.

  1. Remove the serum bottles from the freezer and allow them to acclimate to room temperature for approximately 10 minutes.

  2. Place each container in a 30 to 37 °C water bath or incubator. Excessive temperatures will degrade heat labile nutrients. If using a water bath, prevent the bottle caps from being completely submerged.

  3. Gently swirl or shake the bottles every 10 - 15 minutes until the serum is completely thawed.

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Cryoprecipitates in Serum

Written by admin on July 22, 2014. Posted in Knowledgebase

The method used to thaw serum is crucial to its optimum performance. The key to proper thawing is periodic agitation. If a bottle of serum is not periodically shaken or swirled as it thaws, salt and protein gradients will form throughout the liquid portion. Within these gradients are high concentrations of salts, proteins and lipids which can lead to the formation of crystalline or flocculent precipitates.

These "cryoprecipitates" are not toxic to cell cultures, but they affect the appearance and consistency of each bottle of serum. Small amounts of cryoprecipitates are not uncommon, even in serum that is thawed using the recommended procedure. This is normal and will not affect product performance.

If serum is thawed incorrectly, a much greater amount of cryoprecipitate will form and is often insoluble. Filtering serum to remove cryoprecipitates is not recommended and could result in the loss of nutrients, such as growth factors, mitogens and other proteins.

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