Introduction

In modern biomedical and chemical laboratories, disposable culture tubes are widely used in cell culture, chemical reactions, sample preservation and other critical operations. Their importance in the experimental process cannot be ignored. Since these culture tubes are in direct contact with the experimental samples, their material, size, closure and even whether they are sterilized or not will have a significant impact on the experimental results. Improper selection may lead to cross-contamination, sample loss or experimental data bias, thus affecting the accuracy and reproducibility of the study.

Main Types of Disposable Culture Tubes

There is a wide range of disposable culture tubes, and researchers need to choose the right type according to the purpose of the experiment, the operating environment and the characteristics of the samples. They are categorized in the following three aspects: material, capacity and special function:

1. Classification by material

Disposable culture tubes made of different materials differ in temperature resistance, chemical stability and optical properties:

• Polypropylene: Good resistance to high temperature and chemical corrosion, suitable for routine cell culture, molecular biology experiments and other applications.
• Polystyrene: high transparency, easy to observe the liquid and cell state, commonly used in optical testing, but not high temperature resistance, usually can not be used for autoclaving.
• Glass culture tubes: Although reusable and chemically stable, they are costly, require additional cleaning and sterilization procedures, and present a potential risk of cross-contamination.

2. Classification by capacity

Depending on the volume of sample required for the experiment, the capacity of the culture tubes ranges from micro to large volumes:

• Microcentrifuge tubes: commonly used for sample dispensing, centrifugal precipitation, DNA/RNA extraction and other operations.
• Standard culture tubes: the most commonly used capacity in the laboratory, suitable for cell culture, mixing reaction, sample preservation and other purposes.
• Large-capacity culture tubes: suitable for large-scale cell culture or large amount of solution processing.

3. Classification by special function

The tubes are available with a variety of additional features to meet specific experimental needs:

• Aseptic Pre-sterilized Tubes: factory sterilized by gamma radiation or autoclaving, suitable for experiments with high aseptic requirements.
• With cartridge cap: allows gas exchange, suitable for microorganisms or cell lines that require aeration and prevents contamination from exogenous sources.
• Low Temperature Resistant Tubes: can be safely used in -80℃ or even liquid nitrogen environment, suitable for long-term low temperature preservation of biological samples.
• Graduated/non-graduated tubes: Graduated tubes are convenient for quick estimation and dispensing of liquid volume to enhance the efficiency of experiments.

Key Factors in Selecting Culture Tubes

In the process of experimental design and operation, the selection of appropriate disposable culture tubes is crucial to ensure experimental efficiency and accuracy of results. Researchers should comprehensively consider several key factors:

1. Type of experiment

Requirements for culture tubes vary significantly from experiment to experiment and should be selected according to the content of the operation and the experimental environment:

• For cell culture: the requirements for sterility are extremely high, and the use of sterile pre-sterilized tubes with breathable cartridge caps to ensure gas exchange is recommended.
• PCR / molecular biology experiments: need to be free of DNA enzymes, RNA enzymes and pyrogen-free tubing, often use clean-grade polypropylene tubing.
• Low temperature storage: Tubes with good low temperature resistance should be used to avoid lysis at low temperatures.

2. Sample characteristics

The physicochemical properties of the sample directly influence the choice of material and functional configuration of the culture tubes:

• Liquid or solid samples: determines the required volume and the form of the tube orifice.
• Acid or alkaline samples: highly corrosive samples require chemically resistant materials to avoid tube deformation or contamination.
• Whether to avoid light: light-sensitive samples should choose amber or opaque material culture tube, in order to prevent photodegradation.

3. Sterilization requirements

The need for sterilization and the type of sterilization used are key considerations in the selection of tubing:

• Pre-sterilization vs. self-sterilization: factory pre-sterilized products are suitable for high-throughput experiments, saving time; if the laboratory has autoclave sterilization equipment, you can choose PP tubing that can be autoclaved.
• Sterilization compatibility: For example, PS material is not suitable for autoclaving and is only for single use.

4. Compatibility

The tubes should be well adapted to the laboratory equipment to ensure smooth operation and reliable results:

• Centrifugal compatibility: Tubes used for centrifugation need to be structurally strong to withstand centrifugal forces at high rotational speeds.
• Automation compatibility: For experiments that require the use of pipetting robots, automated dispensing systems, etc., standardized tube sizes must be used.

5. Cost and sustainability

Reasonable control of costs and resource consumption is also an important consideration in meeting experimental needs:

• Disposable vs. reusable: disposable tubes are easy to manage and avoid contamination, suitable for high-throughput experiments; reusable glass tubes are suitable for basic experiments with limited budget.
• Purchase scale: large volume purchase can reduce the unit price, suitable for long-term, large-scale projects; small-scale, customized specifications are more flexible but relatively high cost.

Recommendations for Common Application Scenarios

According to the specific needs of different types of experiments, the following disposable culture tubes are recommended for several common application scenarios, aiming to improve the efficiency and reliability of experiments:

1. Cell cultivation

• Recommended type: sterile polypropylene culture tubes with breathable cartridge caps
• Reason: Polypropylene material has good chemical inertness and biocompatibility, suitable for cell culture fluid. The cartridge cover can realize effective gas exchange, prevent microbial contamination, and meet the gas environment required for cell proliferation.

2. PCR/qPCR molecular realization

• Recommended types: nuclease-free, pyrogen-free specialized PCR tubes or microcentrifuge tubes
• Reason: High purity polypropylene tubes, after strict treatment, can effectively avoid sample degradation or contamination, to ensure accurate and reliable amplification results. Thin-wall design is recommended to improve heat transfer efficiency.

3. Low temperature storage

• Recommended Type: Low Temperature Resistant Polypropylene Tubing with Anti-Freeze Cracking Design and Screw Seal Cap
• Reason: These tubes can be used to store samples for long periods of time at -80°C or even in liquid nitrogen, and the special structure prevents the tube from brittle cracking and sample leakage. Suitable for long-term storage of cell lines, blood samples, proteins or nucleic acids.

4. Centrifuge

• Recommended types: high-tolerance polypropylene tubes, round or conical bottom design, with centrifuge rotors
• Reason: PP tubes have good centrifugal resistance and can withstand high centrifugal forces without deformation or rupture. The conical bottom helps to collect cells or precipitates centrally and increase the recovery rate.

Common Mistakes and Ways to Avoid Them

In practice, experimental failure due to improper selection of culture tubes occurs from time to time. Several common mistakes and corresponding suggestions for solutions are listed below for researchers’ reference:

1. Misuse of non-high temperature resistant materials for autoclaving