What instruments are available in a molecular biology laboratory?

As an upstream technology in genetic engineering, molecular biology’s experimental results and accuracy will determine all downstream steps and the ultimate experimental outcomes. Therefore, it is crucial to establish a fully equipped molecular biology laboratory. Let’s now take a look at the instruments required to build such a laboratory.
 
1. Refrigerators: Depending on the storage requirements of pharmaceuticals, reagents, and various biological preparations, refrigerators with different temperature-control levels are essential. The most commonly used ones include refrigerators set at 4℃, -20℃, and -80℃. A temperature of 4℃ is suitable for storing certain solutions, reagents, and pharmaceuticals. A temperature of -20℃ is appropriate for storing specific reagents, pharmaceuticals, enzymes, sera, prepared antibiotics, and samples of DNA and proteins. A temperature of -80℃ is ideal for long-term cryopreservation of certain samples, E. coli strains, purified samples, and specially treated digestive fluids subjected to low-temperature processing. A chromatography refrigerator operating at 0–10℃ is well-suited for experiments such as electrophoresis, chromatography, and dialysis conducted under low-temperature conditions.
 
2. Incubator: A 37℃ constant-temperature incubator is used for bacterial plate culture and molecular biology experiments.
 
3. Constant-temperature shaker incubator: Used for the amplification of biological engineering strains such as Escherichia coli.
 
4. Water bath: Used for maintaining temperature and conducting various experiments.
 
The 25–100℃ water bath shaker can be used for maintaining a constant temperature in molecular hybridization experiments and various biochemical enzyme reaction assays.
 
A water bath with low-temperature capability can be used for experiments such as the ligation of plasmids and gene fragments in molecular biology, as well as for heat shock of E. coli competent cells at 42°C.
 
5. Oven: Primarily used for drying laboratory glassware, some of which require higher temperatures while others need lower temperatures. For experimental equipment used in RNA-related studies, drying must be carried out in an oven set at 250℃; meanwhile, certain plastic items can only be dried in an oven maintained at 42–45℃.
 
6. Ultrapure Water System: With the rapid advancement of molecular biology, many experiments are placing increasingly stringent demands on water purity. This system uses tap water, distilled water, ion-exchange water, and reverse-osmosis purified water as feed sources, and a magnetically coupled gear pump facilitates water circulation. It is suitable for applications such as PCR, PCR amino acid analysis, DNA sequencing, enzyme reactions, and tissue and cell culture.
 
7. Steam Sterilizer: Most reagents used in molecular biology, as well as laboratory equipment, should be rigorously disinfected and sterilized. For small batches of items, disinfection can be performed on an ad-hoc basis. For large quantities of experimental materials, reagents, and culture media, a large-scale sterilizer can be used, with sterilization carried out on a scheduled basis.
 
8. Filter membrane: Use it for filtering reagents that are not resistant to high temperatures and high pressures.
 
9. Various types of balances: platform scales and precision electronic analytical balances, used for accurately weighing various reagents.
 
10. Measurement of liquid volume: graduated cylinders, pipettes, micropipettes, calibrated test tubes, beakers, Erlenmeyer flasks, and others.
 
11. pH meter: An instrument that directly measures the potential of H+ ions in a solution. It primarily works by using a pair of electrodes to generate different electromotive forces in solutions with varying pH values, which are then expressed as pH readings.
 
pH test paper is suitable only for a rough estimation of the pH value of culture media, phenol-saturated solutions, buffers, or other reagent solutions. However, most reagents require strictly controlled pH levels, necessitating a pH meter with high precision—accurate to two decimal places.
 
12. Spectrophotometer: A spectrophotometer is an instrument that uses the absorption spectrum of a substance in the visible and ultraviolet regions to identify its properties and determine its concentration. It consists of a light source, a monochromator, a cuvette, a detector, and a measuring instrument or display screen. The OD value is one of the convenient indicators for quantifying solutes in many solutions. By measuring the absorbance of a particular solution to monochromatic light generated by the spectrophotometer, it can be used for preliminary determination of nucleic acid solution concentration and purity. The OD value can also serve as an indicator for detecting bacterial cell density.
 
13. High-speed refrigerated centrifuge: Maximum rotor speed 25,000 r/min, maximum centrifugal force 64,983g. Available in both refrigerated and ambient-temperature models, it is widely used for the preparation and manual collection of microorganisms, cellular debris, cells, large organelles, ammonium sulfate precipitates, and immunoprecipitates, among other materials.
 
14. Ultra-clean workbench: Equipped with a UV lamp, an illumination lamp, and also featuring a spirit lamp flame and 75% ethanol or other sterilization equipment, this device provides localized cleanliness. Its principle is that a blower drives air through low- and medium-efficiency filters, and then directs the filtered air over the workbench surface, creating a sterile environment in the experimental operating area.
 
15. Electrophoresis System: Electrophoresis technology is a tool used to detect and identify the purity and content of various biomacromolecules, characterize their properties, and even separate, purify, recover, and concentrate samples.
 
The electrophoresis system consists of a power supply and an electrophoresis tank. The power supply, after passing through a current stabilizer, must provide both stable direct current and stable voltage output. Horizontal electrophoresis tanks are generally divided into micro-sized tanks and large-sized horizontal tanks.
 
16. PCR Instrument: The Polymerase Chain Reaction instrument, also known as a DNA thermal cycler or gene amplifier, enables the enzymatic synthesis of millions of copies of a target DNA fragment by having a pair of oligonucleotide primers bind to both sides of the target sequence on the positive and negative DNA strands. Each cycle of the PCR process consists of three steps carried out at different temperatures: DNA denaturation, primer annealing, and DNA polymerase-catalyzed extension. It should be noted that some laboratories may also require gradient PCR instruments or real-time quantitative fluorescence PCR instruments for certain specialized molecular biology experiments.
 
17. Gel Imaging Analysis System: The Biotek UltraPower™ Visible Light Gel Imager is an excellent choice, priced under 7,000 yuan. It offers detection sensitivity down to the picogram level (while UV and EB can only reach the 5-ng level). Moreover, it eliminates the need for UV and EB, making it safer to use, and its operation and image capture are remarkably convenient.
 
18. Other equipment
 
1. Microwave oven: Convenient for rapidly heating and maintaining constant temperature of certain solutions, as well as for preparing and melting agarose gels for electrophoresis.
 
2. Ice machine: Used to create low-temperature environments required for most experimental procedures involving nucleic acids and proteins, thereby reducing hydrolysis by nucleases or proteases. 3. Chromatography apparatus: (Chromatographic separation) is an effective physical method for separating mixtures containing multiple components.
 
Vacuum imprinting systems and DNA synthesizers/sequencers—these are essential instruments for in-depth research on nucleic acids.
 
4. Magnetic stirrer: Multi-angle rotary mixer, rapid oscillating mixer: used for mixing instruments.
 
5. Tissue homogenizer: An ultrasonic tissue and cell disruptor used for sample separation and purification experiments.
 
6. Fume hood: Many solvents can release toxic fumes; a fume hood is essential. For radioactive experiments, an acrylic shield is also required.
 
7. Glass distillation apparatus, electric heating mantle, and transformer: used for the distillation of organic solvents such as phenol.
 
8. Tip heads, Eppendorf tubes:
 
Micropipette tips (aspiration tips) and Eppendorf tubes (microcentrifuge tubes) are washable and can be reused after silanization and sterilization. For experiments with stringent requirements—such as RNA extraction and preservation—it is recommended to use freshly sterilized tips and Eppendorf tubes. Additionally, it is advisable to keep on hand centrifuge tubes of commonly used sizes (e.g., 1000 ml, 500 ml, 250 ml, 50 ml, 7 ml) as well as cell culture plastic plates in formats such as 96-well, 24-well, 12-well, and 6-well plates.
 
19. Small equipment and tools:
 
Timer, filter membrane, cling film, protective goggles, duckbill forceps, conventional glass or plasticware (including petri dishes, test tubes, beakers, volumetric flasks, and separatory funnels for reagents; reagents that need to be stored away from light should be kept in brown reagent bottles, such as saturated phenol and β-mercaptoethanol), marker pens, various types of gloves (PE, latex, household, acid-resistant, etc.)