Laboratory heat sealers: how can microplates and pouches be sealed hermetically?

Essential for maintaining sample cleanliness and integrity, the heat sealer delivers hermetic, reproducible seals on microplates and pouches. With precise control of temperature, time and pressure, it minimises evaporation in PCR/qPCR, safeguards long-term storage and ensures reliable sterile packaging in production and cleanroom environments. Validatable models with full traceability (parameters, alarms, audit trail) comply with ISO 11607 and GMP requirements. From benchtop use to HTS automation, heat sealing combines performance, ease of use and energy efficiency (impulse technology).

What are the different types of heat sealers?

Three families cover the bulk of lab requirements. The microplate heat sealer applies films onto microplates (SBS 96/384, deep-well). It delivers uniform pressure and stable heating for peelable, permanent or pierceable seals, compatible with PP/PS and solvents (e.g. DMSO). Key criteria: thermal uniformity, T/t/pressure accuracy, flatness, compatibility with plate types and films (optical, aluminium, chemical-resistant), safety (drawer, heat shields).

The bag heat sealer comes as impulse (heats only during the cycle, ideal for PE/PP bags, energy-efficient) and as constant heat or band sealers (for multilayer laminates, aluminium, medical Tyvek). Validatable models monitor and log T/t/pressure, alert on drift and support IQ/OQ/PQ qualification. Selection points: seal width and strength (e.g. 6–12 mm), repeatability, throughput, traceability integration (USB/RS-232, printing on the seal), ergonomics (foot pedal, flap, cool-touch housing).

Maintenance kits (PTFE tapes, jaws, heating elements, silicone pads, filters) ensure consistent performance and extend service life. Good practice: regular cleaning of the sealing surfaces, periodic parameter verification, seal strength testing (e.g. ASTM F88).

Safety & impact: thermal guards, overheat cut-out and alarms prevent burns and non-compliance. Impulse technology lowers energy consumption, and polyolefin films support recyclability where waste streams allow.

Type	Principle	Applications
Impulse (bags)	Brief heating of a band followed by cooling under pressure	PE/PP pouches, routine packaging, low energy consumption
Constant heat/band	Continuously heated jaws/band, T/t/pressure control	Laminated pouches, medical Tyvek, ISO 11607-compliant packaging
Microplate heat sealer	Heating + pressure on film and SBS-format microplate	PCR/qPCR, compound storage, HTS screening, biobanking

In which applications is a heat sealer used?

• Life sciences/molecular biology: leak-tight PCR/qPCR seals, evaporation minimisation, automation and pipetting robot compatibility.
• Pharma/biotech: validation-ready sterile packaging, parameter traceability, ISO 11607 and GMP compliance, seal inspection in cleanroom conditions.
• Chemistry/HTS: reliable closure of microplates and secondary vials for combinatorial chemistry and compound libraries (DMSO/solvent resistance).
• Food industry: sealing of sample bags, sampling kits, retention samples.
• Environment & quality control: securing analysis pouches, regulatory-compliant transport of samples.
• Cosmetics: pilot-lab packaging, stability, material compatibility testing.
Cross-cutting benefits: sample integrity, cleanliness, leak prevention, productivity and reduced scrap thanks to reproducible seals.

The different types of heat sealers and the accessories available

Frequently asked questions about laboratory heat sealers

What’s the difference between impulse and constant heat?
Impulse only heats during the seal cycle (energy-efficient, for PE/PP bags). Constant heat maintains temperature continuously, ideal for laminates/Tyvek and for validated processes.

How do I choose a film for a microplate?
Match the plate material (PP/PS), application (peelable, pierceable, permanent), optics (qPCR) and chemical resistance (e.g. DMSO). Follow the manufacturer’s recommended temperature/time windows.

Which standards apply to sterile packaging?
Operations must be qualified to ISO 11607-2 (control of T/time/pressure, traceability) and GMP, with seal strength testing (e.g. ASTM F88).

Why is my plate warping?
Excessive temperature or pressure, overly long dwell, or an unsuitable film. Lower the settings, check flatness and use plate-specific parameters.

What seal width should I choose?
6–8 mm covers most needs. In critical environments or for transport, 10–12 mm increases strength and makes the seal more visible.

What maintenance is required?
Regular jaw cleaning; periodic replacement of PTFE/heating elements/pressure pads; sensor checks. Schedule calibration checks for T/time/pressure.

Can you print on the seal?
Yes—some models add date/lot/operator or barcodes on the seal band and export parameters via USB/RS-232 for traceability.