How To Choose The Right PCR Sealing Film?

The key to a successful experiment lies in the integrity of the sample seal at the moment of sealing. In PCR experiments, the pcr sealing film serves as the “first layer of protection,” preventing damage from evaporation, aerosols, and cross-contamination. Furthermore, choosing the right film material can enhance qPCR signal reliability. Transparent optical films are ideal for fluorescence detection, while aluminum foil is more suitable for storing light-sensitive samples or for long-term storage.

What is PCR plate sealing film?

PCR sealing film is a laboratory consumable specifically designed for sealing PCR microplates. It is typically made of a material that is heat-resistant, has low autofluorescence, and exhibits excellent sealing properties. The main functions are as follows:

• Preventing evaporation: PCR reactions require high-temperature cycles. If the microplate is not sealed, the sample may evaporate, resulting in concentration fluctuations and experimental failure.
• Preventing cross-contamination: The sealing membrane isolates the liquid in each well, preventing cross-contamination between different samples. This is especially critical in high-throughput or sensitive experiments.
• Ensuring experimental accuracy: A good seal maintains a constant volume in the PCR system, ensuring consistent fluorescence signals and amplification results.
• Adapting to high-temperature cycling: The PCR sealing membrane needs to be resistant to high temperatures (generally 95–105°C) and able to withstand dozens of cycles of thermal cycling without peeling or deformation.

What are the main types of sealing films?

1. Optical Sealing Film PCR

• Features: High transmittance, low autofluorescence, and facilitates fluorescence signal detection
• Applications: Real-time quantitative PCR (qPCR), optical analysis experiments
• Advantages: Does not interfere with optical detection, providing stable data

2. Aluminum Sealing Film

• Features: Opaque, blocks light and moisture, and is low-temperature resistant
• Applications: Protecting photosensitive samples, long-term cryopreservation, and storing chemical samples
• Advantages: Excellent sealing properties and extremely low evaporation rate, but cannot be used for optical detection.

3. Pressure-Sensitive Film

• Features: Seals plates with manual pressure, no additional equipment required
• Applications: Short-term experiments, manual operations, and applications requiring rapid plate sealing
• Advantages: Easy to use, but slightly inferior to heat-sealing film in terms of heat resistance and sealing performance

4. Heat-Sealing Film

• Features: Requires a heat sealer for sealing, provides a secure seal, and is heat-resistant
• Applications: High-throughput automated operations, long-term storage, and PCR applications requiring a strong seal
• Advantages: Optimal sealing performance, strong resistance to evaporation and cross-contamination

5. Silicone Sealing Mat

• Features: Made of high-quality medical or laboratory grade silicone with good flexibility.
• Applications: Repeated operations in high-throughput experiments or automated workstations.
• Advantages: It has good sealing performance and can be reused after multiple cleaning and disinfection.

How to stick a sealing film?

Remove the single sheet of film or foil from the ziplock bag and reseal the bag to maintain an enzyme-free environment.

• Hold the film pcr or foil with the backing facing up.
• Fold the end tab down at the tangent line of the backing.
• If using a pcr film or foil with a single end tab, partially remove the backing paper, then anchor the film or foil to the plate so that it seals across the entire plate, and then continue removing the backing paper. This method eliminates curling and rolling of the film or foil.
• If using a product with two end tabs, peel back the center liner in one smooth, continuous motion. Peeling the liner slowly will minimize curling. Be careful not to touch the adhesive surface of the film.
• Grasp the white ends with both hands and lower the film onto the plate.
• Use a pressure plate to gently press the sealing film or aluminum foil onto the plate. Perform this step at least twice, both horizontally and vertically.

How to clean silicone sealing mats?

1. Initial Rinse

• Rinse with warm deionized or distilled water immediately after use to remove residual reagents, buffers, or biological samples.

• Avoid letting contaminants dry on the surface, as they are harder to remove later.

2. Detergent Wash

• Use a mild laboratory detergent (e.g., 1–2% neutral pH detergent solution).

• Gently scrub using a soft brush or non-abrasive sponge to avoid surface scratches.

• Ensure all wells or sealing protrusions are thoroughly cleaned.

3. Thorough Rinse

• Rinse 3–4 times with deionized water to remove any detergent residues that could interfere with PCR, qPCR, or cell culture work.

4. Disinfection (Optional)

• For biological contamination, soak in 70% ethanol or 10% freshly prepared bleach for 10–15 minutes.

• Rinse thoroughly afterward to prevent chemical carryover.

5. Autoclaving (If Needed)

• Most silicone mats are autoclavable at 121 °C for 15–20 minutes.

• Place them on a clean autoclave tray; avoid stacking tightly so steam can penetrate all surfaces.

6. Drying and Storage

• Air-dry on a clean rack or use a lint-free lab wipe to speed up drying.

• Store in a clean, dust-free container or resealable bag to maintain sterility.

PCR Sealing Film VS qPCR sealing film

PCR sealing film and qPCR sealing film are both used to seal PCR plates, but they’re designed for different applications and have some important differences:

1. PCR Sealing Film

• Purpose: General PCR amplification (end-point PCR).

• Material: Often made of polypropylene or polyester; not always optically clear.

• Properties:

  • Good seal to prevent evaporation and contamination

  • Can withstand typical PCR thermal cycling (high temperatures and rapid changes)

• Limitations:

  • Not optimized for optical transparency

  • May have higher background fluorescence if used in qPCR

• Use Case: Suitable when you only need amplification and will analyze products later (e.g., by gel electrophoresis).

2. qPCR Plate Seal

• Purpose: Real-time quantitative PCR (qPCR) with fluorescence detection.

• Material: Made of optically clear, low-autofluorescence film (often polyester or polyolefin).

• Properties:

  • Excellent light transmission for accurate fluorescence readings

  • Resistant to high temperatures and repeated cycling

  • Designed to prevent condensation or signal distortion

• Limitations:

  • Usually more expensive than standard PCR film

• Use Case: Essential when fluorescence measurement occurs during amplification (e.g., SYBR Green, TaqMan assays).

Summary

Plate seals and silicone caps, though small, are crucial for ensuring experimental reproducibility and safety. Choosing the right type not only saves time and effort, but also improves experimental accuracy and reduces the risk of contamination. From real-time testing and automated operations to long-term storage, the use of different sealing materials has become a crucial component of laboratory operational strategies.

At SDLABIO, we are committed to providing high-quality, sustainable, and efficient laboratory plastic consumables, including aluminum sealing film for pcr and silicone sealing mat. Explore our website to discover our product range, and feel free to contact us for expert advice or tailored solutions to meet your needs.