iST Technical Compliance and Processes Overview

A Microtiter plate, also known as a MicroPlate or MicroWell plate , is a flat plate with multiple wells used as small test tubes.

MicroPlates have become a standard tool in analytical research and clinical diagnostic testing laboratories in the Life Sciences Industry. They simplify the handling of large numbers of samples and enable automation, making them ideal for applications such as filtration, separation, optical detection, storage, reaction, mixing, and cell culture.

A MicroPlate typically has 6, 24, 96, 384 or even 1536 sample wells arranged in a 2:3 rectangular matrix. MicroPlates are available in different types with varying volumes, base shapes, and materials each suited to various applications. Each well can hold between tens of nanolitres to several millilitres of liquid.

IST Scientific provides expert advice in effectively helping you choose the right seal for the right plate in the right application, in the most cost effective way.

MicroPlate Materials

The material from which MicroPlates are made differs according to their application.

• Polypropylene is favoured for incubation and sample storage because of its high resilience to chemicals and temperature, particularly thermocycling. Different sealing options can also be used with polypropylene – especially heat sealing.
• Polystyrene is used for most optical detection MicroPlates.
• Polycarbonate is inexpensive, generally used for disposable MicroPlates for PCR (polymerase chain reaction) – a method of DNA amplification.
• Cyclo-olefin copolymers are now being used to transmit UV light.

Different sizes and types of plate bases, coupled with the correct selection of purity of plastic grades, including ‘low binding’ variants, influence the type of application and ultimately, the seal that will be achieved.

Useful Tips:

• Only MicroPlates that comply with standards established by the Society of Biomolecular Sciences (SBS) should be used.
• Raised chimneys around each well produce the best results.
• MicroPlates that have a raised rim close to the perimeter of the wells should be avoided. This can prevent uniform contact between the hot plate and the wells.
• For flexible MicroPlates which could bend and move during the sealing process, adapter trays to stabilise the MicroPlate position on the plate stage should be used. For example, a flexible 96-well polypropylene MicroPlate can be placed on top of a 96-well polystyrene MicroPlate to provide positional support.

PCR Adapter Plate

Because of the rigorous nature of the PCR process, we offer an adapter tray for PCR MicroPlate support. This ensures integrity and supports optimum results during denaturation, annealing and extension, which are carried out 20-35 times in a thermal cycler to produce replicates of the DNA template.

Heat sealing has become the preferred method of sealing MicroPlates. It creates an airtight and chemically-resistant seal without the complications of using adhesives for the application. Sealing the wells protects the contents from evaporation, condensation, oxidation and cross-contamination during transport or storage.

IST Scientific has a comprehensive range of high performance heat sealing MicroPlate films and foils to meet the needs of the life science laboratory. These are available in individual sheets (LabSheet™) or rolls (LabRoll™) for low, medium and high throughput applications.

Heat Seals

Films or foils are welded to the MicroPlates using heat-sealing devices to produce a secure and effective seal, normally to raised rims around the individual wells of the MicroPlate.

Heat seals are available in a range of materials suitable for peeling, piercing, storage, transport and temporary or long-term sealing. Seals that can withstand sub-zero or high temperatures are also available.

Specifying MicroPlates

Firstly, it is crucial to specify thermal seal-friendly MicroPlates. Seal quality depends on many factors including MicroPlate design, material, batch-to-batch consistency and various other physical features.

Only MicroPlates compliant with standards established by the Society of Bimolecular Sciences (SBS), should be used. SBS plates are STD 96, 384 and 1536 well formats, including deep well and PCR MicroPlates. Skirtless and half-skirt PCR plates require plate supports. Raised rims around each well produce the best results.

MicroPlates produced from polypropylene offer the most effective and reliable heat seal. Other heat seals, however, are designed to be compatible with other specific polymer (MicroPlate) substrates such as polystyrene and COC. Avoid acrylic MicroPlates because they are not compatible with thermal MicroPlate sealing.

The Heat Sealing Process

Specifying the correct heat and dwell time ratios are critical to a good seal in order to ensure secure incubation and storage as well as easy subsequent removal (pierceable seals could have a tendency to adhere permanently to the MicroPlate).  Even and complete sealing rims are a hallmark of closure integrity.

To optimise the process, start by carefully peeling off the seal material by lifting one of the corners. Inspect the underside of the removed material. If there are unbroken impressions of each well, the MicroPlate was properly sealed.

The well impression should match the thickness of the chimney wall.

If the well impressions on the seal are significantly thicker than the chimney wall, decrease the sealing temperature or the dwell time.

Thick impressions may indicate excessive melting of the seal, resulting in difficult removal and reduced resealing capacity.

Heat Sealing Devices

When it comes to heat-sealing MicroPlates, it’s crucial to consider factors such as MicroPlate design, material, and batch consistency. IST Scientific offers a range of high-performance heat-sealing MicroPlate films and foils, along with heat-sealing devices like the iST-207 HeatASeal A1000E.

By selecting the right heat sealing system and using it correctly, laboratories can simplify their sample handling, save time, and ensure their results are accurate and reliable.