1.3: Common Biotechnology Equipment

Biotech Focus

Believe it or not, without cows, the centrifuge used in laboratories all around the world wouldn't have been invented. In 1864, the German engineer Antonin Prandtl created a piece of equipment that separated milk and cream from one another by spinning samples (i.e., centrifuging) at a high speed. Five years later, recognizing its importance, the Swiss physician and biologist Friedrich Miescher applied this same principle to samples in the laboratory. Using a crude, hand-cranked centrifuge like the one shown below (Figure \(\PageIndex{1}\)), Miescher was able to successfully isolate nucleic acids from the nuclei of white blood cells. The early centrifuges of the late 1800s and early 1900s were slow and could only reach revolutions of a few thousand rpm. Theodor Svedberg changed all of that in 1924 with his invention of the first analytical ultracentrifuge that could create centrifugal forces of up to 5000-times the force of gravity. For his work, Theodor won the Nobel Prize in 1926 and, today, the Svedberg unit (S) is used as a measure of how fast a particle will sediment during centrifugation.

Figure \(\PageIndex{1}\): The 19th century centrifuge. Up to four samples could be placed in the brass tube holders at the top of the machine and then spun using the hand crank at the base of the centrifuge. (19th century centrifuge by Kierano, CC BY-SA 4.0)

Introduction

The biotech laboratory contains a myriad of equipment (also known as instruments). Some of this equipment is very basic and can be found in other laboratories, like biology, biochemistry, and chemistry labs (e.g. balances, glassware, pipettes). The basic types of lab equipment include:

1. Equipment for Measuring (i.e. Metrology Equipment)
   1. Balances
   2. pH Meters
   3. Spectrophotometers
2. Equipment for Measuring and Transferring Liquids
   1. Pipettes
   2. Graduated cylinders
3. Equipment for Storing
   1. Glassware
   2. Refrigerators and Freezers
4. Equipment for Safety and Sterility
   1. Personal Protective Equipment (PPE)
   2. Biosafety cabinets
   3. Fume Hoods
   4. Autoclaves
5. Equipment for Analysis
   1. Electrophoresis
   2. Centrifuge

Other equipment is more specialized and is usually found in biology, biotechnology, and biochemistry labs. This equipment can include several types of microscopes, electrophoresis equipment for DNA or protein analysis, PCR machines for DNA amplification, DNA sequencers, and microscopes. To learn about these more specialized pieces of equipment, read Chapter 1.4: Advanced Biotechnology Equipment.

Learning Objectives

By the end of this page, you will be able to:

• List and describe the different types of balances used in a lab
• Describe the different ways to measure the pH of a solution
• Describe the use of a serological pipette
• Describe the use of a micropipette
• Describe the different centrifuges available in a lab
• Know how to properly load a centrifuge

Equipment for Measuring

Metrology is the science of measurement.​ The most common types of measurements: are weight, distance, volume, temperature, pH​. The scientific system of measurement is the metric system. A strong foundation in the metric system is critical to metrology. To review the metric system, go to Chapter 14: Metric System Fundamentals.

Two important components of metrology are accuracy and precision. Accuracy is the degree to which a measurement, calculation, or specification complies to the correct value. Accuracy in measurement is key to the generation of a consistent product in biotechnology. In the biotech lab, accuracy is affected by errors. There are two types of errors that can affect accuracy: random errors, which are fluctuations from measurement to measurement​ and systematic errors, which are consistent errors due to the state of a piece of equipment. ​Eliminating systematic errors relies upon a regular process of testing and calibrating (adjusting) equipment so that they fall within an established margin of error​. In a biotech lab, testing and calibration typically follows a standard operating procedure or SOP. To learn about what an SOP is and why it is used, go to Chapter 12.2: QA/QC Documentation - SOPs, Batch Records, and COAs.

Weighing: Balances & Scales

Instruments for weighing materials are called balances and scales. While they are often used interchangeably, they are not the same thing. A balance measures the mass of an object by comparing it to a known reference mass. A scale measures the weight of an object (i.e., the force exerted by gravity on the object) by using a spring loaded cell or other force-measuring technology.

As defined above, balances are used for the measurement of mass. Mass is measured in grams (or multiples or fractions thereof). Biotechnology procedures require mass measurements ranging from kilograms (1000 grams) to micrograms (10^-6 of a gram). Most biotech laboratories will have more than one type of balance, depending on the amount of material being measured and the degree of accuracy required. The simplest type of balance is a triple-beam balance. The triple-beam balance has a pan where the object to be weighed is placed and three beams, each with a sliding reference weight (i.e. riders) that can be moved along the beam to balance the object (Figure \(\PageIndex{2}\)). The middle beam has the largest (or heaviest) reference weight; the far beam has a reference weight of medium size and weight, and the front beam has the smallest (or lightest) reference weight. To use a triple-beam balance, the object to be weighed is placed on the pan and the reference weights on the beams are moved until the object's mass is "balanced" against the reference weights. The mass is then read.

Figure \(\PageIndex{2}\): The triple-beam balance. Left image: The triple-beam balance has a stainless steel weighing pan attached to three beams, each with a sliding reference weight or rider. Placing an object on the weighing pan lifts the beams. The riders are moved along the beam until they balance the mass of the object on the pan. (Triple Beam Balance by Patricia Zuk, CC BY-SA 4.0) Right image: The balanced riders indicate a mass of 300 + 90 + 9.4 = 399.4 g (Triple Beam Balance Display by Patricia Zuk, CC BY 4.0)

Concept in Action

Interactive Exercise: Reading a Triple Beam Balance

To measure accurately, most labs use electronic balances. An electric balance measures an object's mass using electronic sensors to compare to a reference weight rather than physical reference weights. The mass is displayed using an electronic readout. In general, the more places an electronic balance can read to the right of the decimal point in the balance’s readout, the more accurate it is. This means that a balance that can measure to the nearest gram is less accurate than one that can measure to the nearest 100^th of a gram. Most electronic balances have a sensitivity of +/- 0.01 g, but analytical balances can be sensitive to +/- 0.01mg or less. Balances also have a maximum weight capacity. It is important to never exceed the maximum capacity of a balance or it may be irreparably damaged.

Both the electronic and analytical balance have a stainless steel plate (i.e., a weigh plate) on its weighing surface. This plate is where the sample to be weighed is placed. Because chemicals can damage the balance, they are never placed directly onto the weigh plate. Instead, the sample to be weighed is usually placed in a very light, plastic weigh boat (Figure \(\PageIndex{3}\)). Alternatively, weigh paper may also be used. The balance will have several operational buttons that can power the balance on and off or change its mode. Another button will be the “Tare” button. This “zeroes” the balance before weighing. If you place an empty weigh boat on the plate, the balance will weigh it. If you press the tare button, the balance readout will return to zero and the mass of the weigh boat will be eliminated from what you are about to measure. The analytical balance is very similar to the standard electronic balance. However, its weighing surface is surrounded by a glass enclosure in order to prevent air flow over the weighing surface. This air flow can alter the readout and diminish the precision of the measurement. As such, an analytical balance is used to precisely measure the mass of very small objects.

Figure \(\PageIndex{3}\): Measuring mass with electronic and analytical balances. Left image: Objects are placed onto the balance using plastic weigh boats in order to protect the weigh pan of the balance. (Disposable weigh boats by Lilly_M; CC BY-SA 3.0)
Middle image: The electronic balance has a stainless steel weigh pan for the object, a digital readout, and several operational buttons that control the operation of the balance. (Electronic scale by rebcenter; CC BY-SA 4.0)
Right image: The analytical balance is an electronic balance with a weighing chamber that can be opened to insert the object onto the weigh pan and then closed to eliminate air flow over it. (Analytical scales by rebcenter; Public Domain)

Concept in Action

How to use an Electronic Balance:

1. Turn the balance on
2. If weighing an object:
   1. Press the "Tare" button and allow the readout to "zero"
   2. Place the object on the weigh pan
   3. Allow the readout to stabilize
   4. Record the mass of the object
3. If weighing a chemical:
   1. Place an empty weigh boat or paper on the weigh pan
   2. Press the "Tare" and allow the readout to "zero"
   3. Add the chemical to the weigh boat/paper using a spatula.
   4. Allow the readout to stabilize
   5. Record the mass of the chemical
   6. Repeat steps 3 through 5 until the desired mass of the chemical is obtained

Video: How to use an analytical balance

pH: pH Paper & pH Meters

Most solutions prepared in a biotech laboratory must have a carefully controlled pH. pH is the measure of how acidic or basic a solution is and is a measure of the concentration of H+ ions in a liter of solution.

The formula for pH is: pH=−log[H+]

pH is a scale that ranges from 0 to 14. By definition, the pH value of neutral solution is 7.0; any solution with a pH < 7 is considered acidic; any solution with a pH > 7 is considered basic. pH can be measured in the laboratory using pH indicators, pH paper or a pH meter.

A pH indicator is a chemical added to a solution that changes color when it experiences different pH conditions. Common pH indicators are phenol red and phenolphthalein. At neutral pH, phenol red is red, but turns yellow in an acidic environment. As a solution becomes more basic, the intensity of the red color will increase. Phenolphthalein becomes colorless at pH values below 8.3 (i.e. neutral and acidic solutions) and turns a bright pink in basic solutions with a pH above 8.3. While lacking in precision and accuracy, a pH indicator can be used to give a quick assessment of pH.

A ph estimate can also be achieved using pH paper. pH paper is a special type of paper that will change color when dipped in a solution. pH paper has an array of pH-sensitive chemicals that exhibit a specific color when exposed to a particular pH Figure \(\PageIndex{4}\).

Figure \(\PageIndex{4}\): pH indicator paper. A single pH paper strip is coated with a mixture of pH-sensitive dyes that change color when exposed to a solution (four colored squares). pH can be determined by comparing the colors on the pH strip to a reference chart., allowing users to determine the pH by comparing the color change to a reference chart. (pH paper by Kareen Martin, CC BY 4.0)

More accurate and precise measurements of pH is achieved using a pH meter. A pH meter is a scientific instrument that measures the hydrogen-ion activity in aqueous solutions, indicating its acidity or alkalinity expressed as pH. A pH meter uses two electrodes: a reference electrode and an electrode that is sensitive to H+ concentration. These two electrodes are frequently housed in a single unit as a combination electrode. Because there is a linear relationship between electric potential and pH, a pH meter is actually a voltmeter that reads the difference in electric potential between the two electrodes and converts this difference into a pH reading. As such, the pH meter is sometimes referred to as a "potentiometric pH meter." pH meters can be small and handheld or stationary with arms to hold the electrode apart from the base unit (Figure \(\PageIndex{5}\)). The small handhelds are convenient but sacrifice accuracy for that convenience. The electrodes of the pH meter need to be stored properly – either capped or placed in a storage solution – to prevent them from drying out. A concentrated solution of 3M KCl is frequently used. This solution needs to be rinsed away with distilled water before the electrode is used. Prior to use, the meter also must be calibrated using buffers of fixed pH. The three most common buffers are pH 4.0, 7.0 and 10.0. The pH meter should be calibrated using two of these three buffers and the buffers chosen should bracket the desired pH. For example, if a solution is to be adjusted to pH 5.0, then the pH 4.0 and 7.0 buffers should be used to calibrate the meter.

Figure \(\PageIndex{5}\): The digital pH meter. The digital pH meter determines pH using a glass electrode probe that is immersed in the liquid. The pH of the solution is shown on a digital display. Operational controls can be used to calibrate the meter prior to measurement. (Digital pH meter by S Shamima Nasrin; CC-BY-SA 4.0)

Concept in Action

Interactive Exercise: pH Scale Simulation

Spectrophotometer

A spectrophotometer measures the concentration of a solution by measuring how much light is absorbed by the solutes within the solution. In a spectrophotometer, a lamp provides the source of light. This beam of light can be separated into specific wavelengths that range from UV to visible to infrared. The spectrophotometer is set to a specific wavelength depending on what solute is being measured, as only that wavelength will be absorbed by the solute within the solution. The light passes through the solution and a detector then measures the amount of light that is transmitted. This transmittance can be converted into a numeric value of absorbance that is used to calculate concentration. There are several types of spectrophotometers based on the wavelengths of light they produce. In the biotech lab, the two most common are the visible light spectrophotometer and the UV/VIS (ultraviolet/visible light) spectrometer. The visible light spectrophotometer measures absorbance in the visible spectrum (400 to 700 nm), while the UV/VIS spectrophotometer measures absorbance in the visible range and the UV range (200 to 400 nm). The visible spectrophotometer can be used in the biotech lab to measure the concentration of proteins in solution, while the UV/VIS spectrophotometer, because of its low wavelength range, is used for the determination DNA and RNA concentrations.

Concept in action

Video: How to use a spectrophotometer

Equipment for Measuring and Transferring Liquids

Measuring and transferring liquids in a laboratory is done using graduated cylinders and pipettes. The choice between graduated cylinder and pipette will depend on the volume of liquid being transferred. Graduated cylinders are generally used to measure and transfer larger volumes of liquid (e.g. over 25 mL), while a pipette is used to transfer smaller volumes (e.g. under 25 mL)

Graduated cylinders

Graduated cylinders are one of the most accurate ways of measuring and transferring moderate amounts of liquid. Composed of either clear plastic or glass, the cylinders have volumetric measurements (in milliliters/mL) printed on the side. To measure volume in a graduated cylinder, it is placed on a flat surface and the liquid is slowly poured into it. The liquid should be allowed to settle before reading its volume so that the meniscus, the curved surface of the liquid, can form in the cylinder (Figure \(\PageIndex{6}\)). The meniscus forms due to adherence of the liquid's edges to the graduated cylinder. The volume of the liquid in the cylinder is read using the bottom of the meniscus. For an accurate measurement, the meniscus of the liquid should be read at eye level. A graduated cylinder can measure within 1% of the target volume, making it fairly accurate. However, the larger the cylinder, the less accurate it will be. This is due to the large diameter of the meniscus, which is sensitive to atmospheric pressure. The rule of thumb is to use the smallest available cylinder of sufficient capacity. For example, if a 25 mL volume needs to be measured, a 50 mL graduated cylinder should be used, not a 500 mL.

Figure \(\PageIndex{6}\): The graduated cylinder. (A) A glass graduated cylinder for the measurement of 250 mL of liquid. (B) Volume measurement should be taken at the bottom of the meniscus with the eye placed at the level of the liquid. (Reading a graduated cylinder by Patricia Zuk, CC BY 4.0; adapted from Glass graduated cylinder by Lilly_M, CC BY-SA 4.0 and Graduated Cylinder Illustration by Praphai Donphaimueang, CC BY-SA 4.0)

Serological Pipettes

Serological pipettes are used for dispensing precise volumes that may be too difficult (or small) to measure using a graduated cylinder. A serological pipette is one of several vacuum-assisted pipettes, or pipettes that draw up liquids by creating a vacuum. Serological pipettes can be made of plastic or glass and are used to to deliver volumes between 1 and 100 mL. Examples of serological pipettes include glass Pasteur pipettes, plastic transfer pipettes, and the volumetric serological pipette (Figure \(\PageIndex{7}\)). The vacuum that draws liquid into serological pipettes is created using a "pipet-aid" that can be as simple as a rubber bulb or an electronic pipette pump.

Figure \(\PageIndex{7}\): Pipettes. The types of pipettes used in the biotech lab range from micropipettes (left) to volumetric serological pipettes (top right; shown with an electronic pipette pump) and glass Pasteur pipettes (bottom right; shown with pipette bulb). (Pipette gallery by Squidonius, CC BY-SA 4.0)

The volumetric serological pipette is used to precisely deliver liquids into small containers where spilling from a beaker or cylinder would be likely. Like all volume measuring devices, there are gradations on the side (Figure \(\PageIndex{8}\)). Many pipettes will have gradations on both sides with one side increasing in volume the other side decreasing in volume. Smaller volume pipettes like the 5 and 10 mL have major gradations indicating milliliter (mL) marks (e.g. 1, 2 mL), in addition to minor gradations of 0.1 mL volume. The larger volume pipettes (e.g. 25 mL) will have 1 mL major gradations, but have larger volume minor gradations (e.g. 0.2 mL). Like the graduated cylinder, the volume in a volumetric pipettes should be read using the meniscus held at eye level. All serological volumetric pipettes are designed to hold liquid in their tips. This volume may or may not be taken into account when measuring and dispensing a specific volume. Pipettes in which this residual volume is taken into account are known as "TD-Ex" ("to deliver") pipettes. The TD-Ex pipette will hold a small amount of liquid after dispensing that should not be delivered. Those pipettes in which the residual volume is not taken into account are "TC-In" ("to contain") pipettes, also known as "blow out" pipettes. This means that the liquid must be "blown out" by the pipet-aid in order to dispense the correct volume. To learn more about using a serological pipette, go to Chapter 13.3 Lab Technique: Pipetting.

Figure \(\PageIndex{8}\): Volumetric serological pipettes. Serological pipettes measure and transfer liquids from 1 mL to 100 mL, although 5, 10 and 25 mL volumes are the most commonly used in the biotech lab. The volumetric serological pipette will have volume gradations on one side and may even have gradations on both sides. At the top of these pipettes is information detailing its maximum volume (e.g. 25 mL), the smallest gradation (e.g. 0.2 mL), the temperature it is to be used (e.g. 20°C) and whether it is a "TD-Ex" (T.D.) or "TC-In" (T.C.) pipette. Cell culture serological pipettes will have a cotton plug at the top of the pipette (not shown). (Serological Pipettes by Patricia Zuk, CC BY 4.0)

Pipette Pumps (Pipet-Aids)

The drawing of fluid into a serological pipette and the dispensing of it can be done with a device called a pipette pump or "pipet-aid". A pipette pump creates a vacuum that "sucks" fluids up into a pipette. There are many types of pipette pumps, ranging from a simple rubber squeeze bulb to an electronic pump (Figure \(\PageIndex{9}\)). Most biotech labs use a rechargeable, battery-driven electronic pipette pump is to dispense liquids via volumetric serological pipettes. The electronic pipette pump has a plastic nose cone where the pipette is inserted, and a handle with two buttons. The nose piece will have a filter inside of it to absorb volatile compounds and stop liquids from being aspirated into the pump. The top button on the handle aspirates the liquid into the pipette. The bottom button dispenses the liquid. To learn more about using a pipette pump, go to Chapter 13.3 Lab Technique: Pipetting.

Figure \(\PageIndex{9}\): Pipette pumps. Common pipette pumps used in the lab include (left to right) the rubber Pasteur pipette bulb, the manual pipette pump, and the electronic pipette pump. The pipette bulb and the manual and electronic pipette pumps are used for serological pipettes, while the Pasteur pipette bulb is used with glass Pasteur pipettes. (Pipet Aids by Patricia Zuk; figure created in BioRender. Zuk, P. (2025))

Concept in Action

Video: How to use a serological pipette

Micropipettes

Micropipettes are an essential part of any biotech lab. They are used for dispensing volumes less than 1 mL. Each micropipette has the same basic component parts: a plunger for aspirating and dispensing fluids, a volume adjustment knob, a volume display in the body of the micropipette, a shaft for the attachment of a pipette tip and a tip ejector (Figure \(\PageIndex{10}\)).

Figure \(\PageIndex{10}\): The micropipette is used to dispense volumes less than 1 mL. (A) The basic components of the micropipette are a plunger for aspirating and dispensing fluids, a volume adjustment knob, a volume display in the body of the micropipette, a shaft for the attachment of a pipette tip and a tip ejector. (B) The volume display is found in the body of the micropipette and indicates the volume being dispensed. (The micropipette by Patricia Zuk, CC BY 4.0; (adapted from Gilson schematic by Squidonius, CC BY-SA 3.0 and Micropipette part by Superchilum, CC BY-SA 3.0)

There are several sizes of micropipettes depending on the maximum volume they can dispense:

1. a P2 that accurately dispenses volumes from 0.2 uL to 2.0 uL
2. a P10 that accurately dispenses volumes from 1 uL to 10 uL
3. a P20 that accurately dispenses volumes from 2 uL to 20 uL
4. a P50 that accurately dispenses volumes from 5 uL to 20 uL
5. a P100 that accurately dispenses volumes from 10 uL to 100 uL
6. a P200 that accurately dispenses volumes from 20 uL to 200 uL
7. a P1000 that dispenses volumes from 100 uL to 1000 uL

The range of a micropipette is very important. Working outside of the range of a micropipette will decrease its accuracy and precision and can even damage or break it. Because they are very precise pieces of lab equipment, micropipettes are calibrated on a regular basis to ensure that they are precise and accurate. For more information about how to use a micropipette, go to Chapter 13.13 Lab Technique: Pipetting.

Concept in Action

Video: How do you use a micropipette?

Equipment for Storing

Beakers

A beaker is a simple container for making solutions, stirring, heating liquids, and adjusting pH. Beakers are generally cylindrical in shape, with a flat bottom (Figure \(\PageIndex{11}\)). Most have a small spout (or "beak") to aid in pouring. Most will also have measurement gradations printed on the side. Beakers are available in a wide range of sizes, from 1 mL up to several liters. The graduations on the side are not to be used for volumetric measurement as they are usually only within ±5% of the actual volume.

Erlenmeyer flasks

An Erlenmeyer flask has slanted sides and a narrow opening (Figure \(\PageIndex{11}\)). The flask’s design facilitates swirling and mixing of the contents without spilling. The narrow opening of the flask can be covered with Parafilm or another impermeable cover or a glass stopper allowing for the temporary storage of liquids inside the flask. Some flasks come with threaded openings and screw cap or culture tops that “snap” onto the opening. These flasks are used to grow liquid cultures of micro-organisms like bacteria and yeast. Like beakers, the Erlenmeyer flask should not be used for measuring, although the gradations on the outside provide a rough guide for measuring a volume. A 100 mL Erlenmeyer flask will be accurate to within ±0.2 mL. Erlenmeyer flasks with capacities from 25 mL to 4 L are commonly found in laboratories.

Volumetric Flasks

Volumetric flasks are used to make solutions for analytical assays. There are no graduated markings in a volumetric flask (Figure \(\PageIndex{11}\)). When liquids are brought to the indicator line, they have the highest degree of volumetric accuracy for glassware. For example, a 100 mL volumetric flask can have an accuracy of +/- 0.1 mL.

Reagent Bottles

Reagent bottles are used to store solutions and are available in many shapes and sizes (Figure \(\PageIndex{11}\)). The bottles can be made of plastic or glass, depending on the solution that is being stored and how it is to be stored. For example, 1M NaCl can be stored in a plastic reagent bottle at room temperature whereas HCl needs to be stored in a glass bottle. It is important to realize that while strong acids need to be stored in glass bottles, a strong base will react with the glass and must be stored in a plastic bottle. A chemical’s MSDS (Material Data Safety Sheet) will have information on how to properly store the chemical when in solution. Many reagent bottles are made of Pyrex glass so that they are heat resistant and can be heated or autoclaved.

Figure \(\PageIndex{11}\): Laboratory glassware. Glass 2000 mL beaker (by Lilly_M, CC BY-SA 3.0), Erlenmeyer flask (by Hannes Grobe CC BY-SA 2.5), Brand volumetric flask (by Lucasbosch, CC BY-SA 3.0) and Laboratory glass bottles (by Lilly_M, CC BY-SA 3.0).

Refrigerators and Freezers

Many reagents used in biotech laboratories require specific storage temperatures to prevent their degradation, maintain their stability, and prevent contamination. While the use of household refrigerators and freezers may be attractive due to their costs, laboratory refrigerators and freezers are more durable and provide better insulation and more precise temperature control. In addition, many lab refrigerator and freezers come with monitoring systems to warn users when the temperature deviates from its set range.

Different types of refrigerators can be found in a biotech lab, including the:

• General laboratory refrigerator (4°C): used for storing chemicals and reagents such as culture media and molecular and cell biology reagents that are sensitive to extreme cold (e.g. some antibodies and enzymes); can come equipped with either glass doors or a metal door for light-sensitive reagents
• Pharmaceutical refrigerator (4°C): used for storing vaccines, medicines, and blood and plasma samples used for diagnostic tests
• Explosion-proof refrigerators (4°C): used for the storage of flammable or volatile substances (e.g. ethanol)

Different types of freezers can be found in a biotech laboratory, including the:

• Standard laboratory freezer (-20°C to -30°C): used for storing common reagents for molecular biology procedures (e.g. PCR, DNA sequencing), chemicals (e.g. ethanol, phenol), and biological samples (e.g. DNA, proteins, enzymes, antibodies)
• Ultra-low temperature freezer (-80°C): used for long-term storage of biological samples, such as bacteria cultures, tissues, RNA, and proteins
• Cryogenic freezer (-150°C to -196°C): also known as liquid nitrogen storage; used for long-term storage of eukaryotic cell cultures and other highly temperature-sensitive biological materials (e.g. viruses)

It is important to stress to those working in the lab that laboratory refrigerators and freezers are to be used for lab samples and reagents and not for food and drink storage.

Equipment for Safety and Sterility

Maintaining safety and ensuring the quality of experiments are paramount in biotechnology labs. Several pieces of equipment in the biotech lab can provide users with the ability to perform experiments under safe conditions and decrease the chance of microbial contamination.

Personal Protective Equipment (PPE)

Personal protective equipment (PPE) protects the user against specific hazards in the laboratory. Safety glasses, lab coats and gloves are examples of PPE that are commonly used in biotech labs. The type of glove chosen will depend on the potential hazard that might be encountered in the lab. Most gloves used in biotech labs are either latex, nitrile, or vinyl. Latex is the simplest material and the most common kind of glove. However, many people may exhibit skin sensitivity to latex. Some disposable latex gloves are also flammable, which would prevent their use when working with bacteria. Nitrile gloves are used a common alternative to latex. Nitrile is thicker than latex, does not irritate most user’s skin and provides a more substantial barrier. The use of a lab coat in a biotech lab may be mandatory or optional, depending on the lab. However, wearing a lab coat is recommended as it protects clothing and skin. Finally, while not necessary for every lab protocol, safety glasses are important pieces of PPE and should be selected based on the specific risks anticipated when working in a biotech lab (e.g. splash risk, shortwave, ultraviolet radiation).

Biological Safety Cabinet (BSC)

The Biological Safety Cabinet (BSC) is an enclosed, ventilated workspace for safely working with biological materials that require a defined biosafety level. Provide a controlled environment to handle pathogenic organisms and prevent contamination of samples and exposure to researchers. There are several types of BSCs, with each providing different levels of protection to the user, the environment, and the biological product. To read more about the BSC, go to Chapter 6.3: Cell Culture Equipment and Chapter 13.12: Lab Technique - Cell Culture.

Fume Hood

A fume hood is a ventilated enclosure that is used in many biotech labs to safely handle hazardous chemical, vapors, and fumes. The fume hood works by pulling air in from the room, therefore pushing the contaminated air away from the user. The contaminated air is either expelled directly to the outside environment through a ventilation system or by filtered through a specialized system before expelling it. It is important to remember that a fume hood is not a BSC. While both protect the user in some manner, the fume hood does not prevent microbial contamination and the BSC does not provide protection from hazardous vapors and fumes.

Autoclave

An autoclave is a high-pressure steam sterilizer that uses moist-heat sterilization to sterilize equipment, liquid reagents, and media (Figure \(\PageIndex{12}\)). Charles Chamberland (1851–1908) designed the modern autoclave in 1879 while working in the laboratory of Louis Pasteur. The autoclave produces high-temperature steam to sterilize items such as surgical equipment and laboratory glassware, without damaging them. This high temperature also sterilizes liquids, killing bacteria, viruses, and fungi, without degrading the components of the liquid media or reagent. Standard operating temperatures for autoclaves are 121°C or, in some cases, 132°C, typically at a pressure of 15 to 20 pounds per square inch (psi). The length of exposure depends on the volume and nature of material being sterilized, but is typically 20 minutes or more, with larger volumes requiring longer exposure times to ensure sufficient heat transfer to the materials being sterilized. The steam must directly contact the liquids or dry materials being sterilized, so containers are left loosely closed and instruments are loosely wrapped in paper or foil.

Figure \(\PageIndex{12}\): An autoclave. Autoclaves are designed to sterilize liquids and solid materials using pressurized steam. This autoclave contains several pieces of equipment ready to be sterilized. (Sterilisator by KOchstudioO; CC BY-SA 3.0)

In general, the air in the chamber of an autoclave is removed and replaced with increasing amounts of steam, resulting in increased interior pressure and temperatures above the boiling point of water. The two main types of autoclaves differ in the way that air is removed from the chamber. In gravity displacement autoclaves, steam is introduced into the chamber from the top or sides. Air, which is heavier than steam, sinks to the bottom of the chamber, where it is forced out through a vent. The steam replaces the air. However, complete displacement of air is difficult, so longer cycles may be required for the type of autoclave. In pre-vacuum sterilizers, air is removed completely using a high-speed vacuum before introducing steam into the chamber. Because air is more completely eliminated, the steam can more easily penetrate wrapped items. Many autoclaves are capable of both gravity and pre-vacuum cycles, using the former for the decontamination of waste and sterilization of media and unwrapped glassware, and the latter for sterilization of packaged instruments. The autoclave is still considered the most effective method of sterilization and is crucial for maintaining aseptic conditions in the laboratory.

Equipment for Analysis

The Centrifuge

A centrifuge is used to separate or collect materials of different densities by spinning them at high speeds. Through the generation of centrifugal force, denser materials, such as cells, subcellular organelles, and insoluble particles, are pushed to the bottom of the centrifuge tube, while the lighter components remain at the top. The centrifuge works by spinning a rotor, which is designed to hold tubes of specific volumes. Biotech centrifuges will typically have a fixed-angle rotor and a swinging-bucket rotor (Figure \(\PageIndex{13}\)). The fixed-angle rotor holds the sample tubes at a specific angle, allowing for faster sedimentation rates of dense materials. A swinging-bucket rotor holds the tubes vertically at rest but allows the tubes to "swing-out" to a horizontal position when spinning. Such a rotor allows for better separation between materials of different densities. The choice of rotor will depend on what the centrifuge is being used for. The speed of the centrifuge can be measured as revolutions per minute (rpm) or relative centrifugal force (RCF). These two measurements are not the same but are related to one another. RCF is the actual centrifugal force exerted on the sample, while rpm is the actual spinning speed of the centrifuge. Two centrifuges spinning at the same rpm with different rotors will have two different RCF measurements. RCF can be converted into rpm using a mathematical formula that takes the size of the rotor into account.

Figure \(\PageIndex{13}\): The centrifuge. Left image: the centrifuge has a centrifugation chamber into which the rotor and samples are placed. Rotors can be "fixed angle" or "swing-out". A control panel controls centrifuge speed and temperature (if possible). (Tabletop centrifuge by Patricia Zuk, CC BY 4.0)
Top right image: fixed angle rotors hold centrifuge tubes at a specific angle during centrifugation. (Beckman TLA55 by Nadine90; CC BY-SA 3.0)
Bottom right image: swing-out rotors spin centrifuge tubes in a horizontal position. Rotors often come equipped with tube adaptors to allow for the centrifugation of many tube sizes. (Eppendorf centrifuge rotor by Kitmondo Marketplace; CC BY 2.0)

Centrifuges are used in biotech labs to pellet cells within a liquid, separate liquid components, purify proteins, and isolate DNA. There are several types of centrifuges (Figure \(\PageIndex{14}\)), including the:

• Preparative centrifuge: used to isolate and purify substances (e.g. subcellular organelles, DNA, proteins); spins at higher speeds (up to 30,000 rpm); different sized rotors can hold vessels as small as a few milliliters to as large as a liter; often refrigerated so that heat-sensitive material, such as cells and proteins, are not damaged due to the high heat generated during centrifugation
• Tabletop centrifuge: used to pellet cells and separate liquids; a small centrifuge that spins at slower speeds (less than 5,000 rpm); rotors hold tubes from a few milliliters to 50 mL; typically use fixed angle and swing-out rotors; clinical versions use swing-out rotors to separate biological fluids and pellet cells; refrigerated options available
• Micro-centrifuge: used to separate liquids and to pellet materials like cells, insoluble proteins, and DNA; a compact centrifuge that spins from 1,000 rpm to 14,000 rpm; uses a fixed-angle rotor that holds 2.0 mL (or smaller) micro-centrifuge tubes; refrigerated options available
• Ultra-centrifuge: used to isolate and study extremely small materials like ribosomes, DNA, RNA, proteins, and viruses, like DNA; spins at very high speeds (up to 100,000 rpm) within a vacuum chamber to prevent overheating; preparative versions spin a higher speeds versus analytical versions; uses fixed angle rotors only and specialized tubes designed to withstand high RCF.

Figure \(\PageIndex{14}\): Types of centrifuges. The tabletop centrifuge (left) and microcentrifuge, also called a "microfuge" (right), are two common types of centrifuges found in biotech laboratories. (Centrifuges by Kareen Martin; CC BY 4.0)

To centrifuge, the materials are placed into the appropriately sized centrifuge tube or bottle. The specific tube or bottle used will depend on the volume of the sample and the speed of centrifugation. Centrifuge tubes and bottles are created to withstand centrifugal forces. Higher speed/centrifugal force will require thicker plastic. The samples are loaded into the centrifuge, the lid closed, and the samples are spun at the required speed and temperature. However, because of their high rotation rates, samples must be loaded correctly in order to prevent injury or breaking the centrifuge. Specifically, the samples must be loaded such that they are balanced within the rotor (Figure \(\PageIndex{15}\)).

Figure \(\PageIndex{15}\): Correct and incorrect loading of samples in a centrifuge. The samples shown in A and B are loaded into the rotor correctly and are balanced. Balanced samples will have the same number of empty spaces between them. The samples shown in C and D have been loaded incorrectly. The centrifuge in C has only one tube, another one with the same amount should be added on the opposite side. D has 4 tubes, 2 side by side and 2 others randomly placed. (Centrifuge Loading by Kareen Martin; CC BY 4.0)

Concept in Action

Video: How to use a centrifuge

Electrophoresis Equipment

Electrophoresis is a laboratory technique that uses an electric field to separate fragments of DNA, RNA, or proteins according to their sizes and electric charges. This basic lab technique is known as electrophoresis. In electrophoresis, samples containing fragments of nucleic aids or proteins are loaded into wells created in a polymeric gel (i.e. agarose or acrylamide) and an electric field applied. The negatively charged nucleic acids or proteins will move through the gel towards the positive electrode (anode). The smaller fragments will move faster through the gel and travel further towards the anode. While the larger fragments will move slower. In order to perform electrophoresis, a biotech lab will have several kinds of electrophoresis "tanks" or "rigs" that are designed for either nucleic acids (i.e. DNA and RNA) or protein. Nucleic acid electrophoresis is typically done using a horizontal tank, while protein electrophoresis is done in a vertical tank (Figure \(\PageIndex{16}\)). To learn about electrophoresis of DNA, go to Chapter 13.1: Lab Technique - Agarose Gel Electrophoresis of DNA. To learn about electrophoresis of proteins, go to Chapter 13.10: Lab Technique - SDS-PAGE.

Figure \(\PageIndex{16}\): Electrophoresis equipment. Left image - an electrophoresis system for DNA and RNA analysis, including (clockwise from the left) the horizontal electrophoresis tank, the power supply, and the gel tray with inserted comb. Right image - an electrophoresis system for protein analysis, including (clockwise from the left) the vertical electrophoresis tank, the power supply, and the gel plates with comb inserted. (DNA and Protein Electrophoresis Equipment by Patricia Zuk, CC BY 4.0)

Molecular Protocols

• Lab Technique: Pipetting
• Lab Technique - Agarose Gel Electrophoresis of DNA
• Lab Technique - SDS-PAGE
• Lab Technique - Cell Culture

Key Concepts

The equipment used in biotechnology is diverse and specialized, reflecting the complexity and precision required in this field. Understanding the functions and applications of these tools is essential for anyone working in or studying biotechnology, as they form the foundation for scientific discoveries and technological advancements. Some important concepts to remember are:

• Basic laboratory tools include equipment for measuring, transferring liquids, storing, safety and sterility, and analysis
• Equipment for measuring includes balances and scales, pH meters, pH paper, and spectrophotometers
• Equipment for transferring small amounts of liquids include serological pipettes and micropipettes
• Serological pipettes require vacuum-producing devices like manual and electronic pipette pumps
• Equipment for transferring larger volumes of liquids includes graduated cylinders
• Equipment for storing liquids includes beakers, flasks, and reagent bottles
• Equipment for storing materials at controlled temperatures include refrigerators and freezers
• Freezers can range from standard models (-20°C to -30°C), to ultra-low freezers (-80°C), to cryogenic freezers, also known as liquid nitrogen containers (-150°C to -196°C)
• Safety equipment includes personal protective equipment (PPE) like gloves, biosafety cabinets, fume hoods, and autoclaves
• Equipment for basic lab analysis includes electrophoresis equipment for DNA, RNA, and protein separation, and centrifuges
• Centrifuges can range from low-speed table-top models to high-speed "ultracentrifuges"

Glossary

Autoclave - a high-pressure steam sterilizer that uses heat and pressure to sterilize equipment, liquid reagents, and media

Balance - a piece of equipment to measure the mass of an object

Buffer - a solution that resists changes in pH

Biological Safety Cabinet (BSC) - an enclosed, ventilated workspace for safely working with biological materials that require a defined biosafety level

Centrifuge - a piece of equipment that uses centrifugal force to separate materials of different densities

Electrophoresis - a laboratory technique that uses an electric field to separate fragments based on their size and charge

Fume Hood - a ventilated enclosure that is used to safely handle hazardous chemical, vapors, and fumes

Mass - the quantity of matter within an object

Meniscus - the curved surface of a liquid

Metrology - the science of measurement

Metric System - a standardized system of measurement that uses a set of base units a nomenclature based on decimal-based prefixes

Personal Protective Equipment (PPE) - lab equipment worn to protect a user against chemical and biological hazards

Pipette - a piece of equipment used to measure and transfer small amounts of liquid; found as types including Pasteur pipettes, serological pipettes, and micropipettes

pH - a logarithmic scale used to measure how acidic or basic a solution is

pH Indicator - a chemical added to a solution that changes color based on the pH of a solution

pH Meter - a piece of equipment that measures the pH of a solution

pH Paper - a type of paper that changes color based on the pH of a solution

Random Error - fluctuations from measurement to measurement​

Relative Centrifugal Force (RCF) - the amount of force applied to an object using a centrifuge

Revolutions per minute (rpm) - a unit of rotational speed for rotating machines like centrifuges

Scale - a piece of equipment to measure the weight of an object

Spectrophotometer - a piece of equipment that measures the amount of photons of light absorbed by the solutes in a solution; used to determine the concentration of a solution

Systemic Error - consistent errors due to the state of a piece of equipment

Tare - a function on a balance or scale that removes the weight of a container holding the object being weighed

Weight - the force exerted on an object due to gravity