Screw Cap Tubes

What Are Screw Cap Centrifuge Tubes?

Screw cap centrifuge tubes are polypropylene vessels with a threaded closure that rotates to create a compression seal, typically reinforced by a silicone or polyethylene O-ring. This seal design prevents evaporation, leakage, and contamination under conditions where a snap cap fails, including high-speed centrifugation up to 20,000 × g, repeated freeze-thaw cycles from −80 °C to +121 °C, exposure to volatile organic solvents, and long-term cryogenic storage. Available in volumes ranging from 0.5 mL to 2.0 mL, these tubes are commonly used in proteomics, genomics, drug discovery, biobanking, and other applications where maintaining sample integrity is critical throughout multiple processing steps.

Choose screw cap tubes instead of snap-cap tubes when working with volatile samples, repeated freeze-thaw cycles, high centrifugal forces above 16,000 × g, or long-term storage at −80 °C.

In this part, you will discover:

• 0.5mL, 1.5mL, 2.0mL (for small to moderate volume applications)

• O-ring caps: Leak-proof, prevents evaporation

• Tubes only: Compatible with existing caps

• Sterile: For sensitive, contamination-prone work

• Non-sterile: Cost-effective for routine use

How to Choose Screw Cap Tubes

O-Ring vs Non-O-Ring Seal

Screw cap tubes with integrated silicone O-rings provide a hermetic seal that is ideal for volatile chemicals, infectious materials, and valuable samples where evaporative loss must be minimized. Non-O-ring designs, including rim-seal and plug-seal caps, are suitable for most routine molecular biology storage applications at temperatures between −20 °C and −80 °C and are often easier to open when working in cold environments.

Internal Thread vs External Thread

Internal-thread screw cap tubes maintain a smooth exterior profile and are generally compatible with standard microcentrifuge rotors without requiring additional adapters. External-thread designs provide easier cap handling while wearing gloves and are frequently used in self-standing tube formats that can be placed directly in racks.

Volume Selection: 0.5 mL vs 1.5 mL vs 2.0 mL

0.5 mL screw cap tubes are commonly used for concentrated enzymes, antibodies, and other valuable reagents where minimizing dead volume is important.

1.5 mL screw cap tubes are the standard choice for molecular biology applications, including RNA and DNA storage, pellet recovery, and protein fraction collection.

2.0 mL screw cap tubes provide additional capacity and headspace for bead-based extraction methods, precipitation workflows, and sample mixing procedures.

Nest Scientific offers 0.5 mL, 1.5 mL, and 2.0 mL self-standing screw cap tubes with multiple cap color options to simplify sample identification and organization.

Sterility Grade

Sterile screw cap tubes are gamma- or E-beam-irradiated to a sterility assurance level (SAL) of 10⁻⁶ and are recommended for RNA applications, clinical specimen processing, and cell culture workflows. Non-sterile RNase-free and DNase-free tubes provide a cost-effective alternative for DNA and protein-related applications.

Compare Screw Cap Tube Options

Nest Scientific self-standing screw cap tubes are available in 0.5 mL, 1.5 mL, and 2.0 mL volumes with external threads and integrated sealing rings. Rated up to 20,000 × g, these tubes are ideal for general sample storage and laboratories that use color-coded organization systems.

Globe Scientific self-standing screw cap tubes with silicone O-rings are offered in 1.5 mL and 2.0 mL formats. Their enhanced sealing performance makes them particularly suitable for volatile samples, cryogenic storage, and applications where maximum sample protection is required. These tubes are rated up to 20,000 × g.

Conical-bottom screw cap tubes are commonly available in 1.5 mL formats with internal threads and optional sealing systems. Their conical design improves pellet recovery and makes them well suited for precipitation and centrifugation workflows. These tubes can withstand centrifugal forces up to 20,000 × g.

Amber screw cap tubes are available in 1.5 mL and 2.0 mL capacities and feature O-ring seals for additional protection. Designed for light-sensitive samples, they are typically rated up to 16,000 × g and help protect reagents from light-induced degradation.

Specifications Context

Globe Scientific and Nest Scientific screw cap microtubes are manufactured from USP Class VI virgin polypropylene and are certified RNase-free, DNase-free, and non-pyrogenic by lot. Nest Scientific screw cap tubes are available with six cap color options, including blue, red, yellow, purple, green, and natural, and are typically packaged in packs of 50 tubes with 500 tubes per case. These tubes are suitable for temperatures ranging from −80 °C to +121 °C.

As of 2026, MBP stocks both self-standing and conical-bottom screw cap tube formats from Globe Scientific and Nest Scientific. Availability may vary by volume, cap style, and color configuration.

Don't let equipment choices hold back your next breakthrough. Contact our team at Molecular Biology Products Inc. for a custom quote.