Category: Product Knowledge

Short answer: these terms describe five different things, and suppliers often blur them together:

Term	What it actually describes
USP Class VI	The material — a biocompatibility classification for plastics in contact with biological samples
DNase-free / RNase-free	Biological cleanliness — no residual nuclease activity that would degrade DNA or RNA
Pyrogen-free	Absence of pyrogens (endotoxin), usually stated as a numeric limit
SAL 10⁻⁶	Sterility assurance — a probability, not a yes/no property
100,000-class	The manufacturing environment, not the product’s cleanliness

A product can legitimately be USP Class VI and non-sterile; conversely, a sterile product can still be contaminated with nucleases. Understanding which question each term answers is what lets you specify the right thing — and check it.

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1. USP Class VI — a material classification

USP Class VI comes from the United States Pharmacopeia’s biological reactivity tests for plastics. Class VI is the most stringent of the classes and is the grade commonly required for materials intended to contact biological samples.

Two things worth being clear about:

• It is a property of the resin, not of the finished part’s cleanliness.
• It says nothing about sterility or nuclease contamination.

For lab consumables, USP Class VI polypropylene is the usual choice for tubes, vials and plates; polystyrene for culture ware; and PET / PETG for bottles where optical clarity and gas barrier matter.

2. DNase-free and RNase-free — the one that ruins experiments

Nucleases are enzymes that degrade nucleic acids:

• DNase degrades DNA template
• RNase degrades RNA

Both are extremely stable and can persist on surfaces that look perfectly clean. For PCR and RNA work, a consumable that is not certified nuclease-free can destroy the assay without producing any visible sign of a problem — the reaction simply underperforms or fails.

This is why “DNase-free and RNase-free” should be stated as a release criterion for the batch, not as a general marketing claim. Ask to see it on the CoA.

3. Pyrogen-free and the endotoxin limit

Pyrogens are substances that cause fever; bacterial endotoxin is the most common one. For consumables used with cell culture or injectable workflows, the requirement is normally expressed numerically — for example endotoxin < 0.1 EU/mL.

Note the distinction from sterility. Sterilization kills organisms; it does not necessarily remove the endotoxin those organisms left behind. A product can pass sterility and still fail a pyrogen specification.

4. SAL 10⁻⁶ — sterility as a probability

SAL (Sterility Assurance Level) of 10⁻⁶ means there is a probability of fewer than one non-sterile unit in a million after sterilization. It is a statistical statement about the process, established through validation of the sterilization cycle.

Gamma irradiation is the usual method for single-use plastic consumables because it penetrates sealed packaging and does not require heat. When you ask about sterility, the useful question is not “is it sterile” but “to what SAL, by which method” — and, for a specific batch, “which cycle was this lot run on”.

5. Cleanroom class — the environment, not the product

A 100,000-class cleanroom describes the manufacturing environment in terms of permitted particle counts per cubic foot of air. Under the older US FED-STD-209E naming, Class 100,000 is commonly equated with ISO 8 in the current ISO 14644 classification.

Why this matters: a cleanroom class constrains how much particulate and microbial contamination can enter during moulding and assembly. But it is a factory-level condition, not a certificate about the item in your hand. That is what the batch-level release criteria are for.

6. The additives nobody asks about

Two formulation choices affect sensitive assays and are rarely volunteered:

• Mold-release agents — used in moulding to help parts release from tooling. They can leave residue that inhibits PCR or affects cell growth.
• Colour additives — masterbatch colours can fluoresce or interfere with optical readouts.

For molecular and cell-culture work, the specification worth requesting explicitly is no mold-release agents and no colour additives.

7. Which grade do you actually need?

Application	Material	Cleanliness	Sterility
Routine sample handling, storage	PP / PS, ideally USP Class VI	Nuclease-free if downstream nucleic-acid work	Usually optional
PCR / qPCR	PP, USP Class VI	DNase-free and RNase-free required	Optional, but must not introduce contamination
Cell culture	PS with TC treatment, USP Class VI	Pyrogen-free, low endotoxin	Sterile, SAL 10⁻⁶
Cryogenic storage (LN2)	PP, USP Class VI	Nuclease-free where samples are nucleic acid	Sterile usual
Buffer / reagent preparation	PET / PETG / HDPE	Not usually critical	Optional

8. How to verify any of this

Claims are cheap. Ask for:

1. A CoA from a specific recent batch — it should name the tests: sterility, endotoxin, cytotoxicity, RNase/DNase residues.
2. The numeric endotoxin limit, not just the phrase “pyrogen-free”.
3. The SAL and the sterilization method.
4. The material grade declared for the resin, not just “medical-grade plastic”.
5. Third-party test reports where an independent result is needed.

If a supplier cannot supply a CoA on request, the other claims are not worth evaluating.

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Frequently asked questions

Does USP Class VI mean the product is sterile? No. USP Class VI is a material biocompatibility classification. Sterility is a separate property, described by the sterilization method and the SAL.

Is sterile the same as pyrogen-free? No. Sterilization kills organisms; it does not necessarily remove the endotoxin they leave behind. A product can be sterile and still fail an endotoxin limit.

What does SAL 10⁻⁶ mean? It means a probability of fewer than one non-sterile unit in a million — a validated property of the sterilization process, not a per-unit inspection result.

Why does DNase/RNase contamination matter so much in PCR? Because trace nuclease activity degrades the DNA template or RNA before or during amplification. The assay then underperforms or fails with no obvious physical indication of contamination.

What does a 100,000-class cleanroom mean? It describes the permitted airborne particle count in the manufacturing environment — a factory condition, commonly equated with ISO 8. It is not a certificate about the cleanliness of an individual item; that comes from batch-level release criteria.

Does BUNSEN publish ISO or CE certificates? No ISO or CE certificate number is published. Claims of that kind should be supported by a certificate number and issuing body — if a supplier cannot provide those, treat the claim as unverified.

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Note: The information on the scientific research products above is for reference only!

Short answer: OEM/ODM for lab consumables follows six stages — scope definition, specification freeze and MOQ quotation, sampling and approval, production and sterilization, documentation, then packaging and shipping. The two stages that decide whether the project goes smoothly are stage 2 (freezing the specification, because that is what fixes MOQ and lead time) and stage 3 (approving a physical sample before tooling and printing are committed).

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1. Scope definition — what is actually customisable

Start by separating what can be changed from what cannot:

Customisable

• Colour — tube body and cap
• Laser-printed logo — permanent marking, not a label
• Barcode / QR code — including multi-code formats for biobanking
• Individual packaging — bagged, racked, or blister configurations
• Sterilization — sterile or non-sterile, and specific sterilization methods

Not customisable (and should not be)

• SBS footprint and well geometry for microplates — changing these breaks instrument compatibility and defeats the purpose of the product.
• Material grade below the required biocompatibility class — the raw material determines whether the part is usable in cell culture or PCR.

A supplier who offers to change the well geometry to suit your branding is offering to make the product unusable.

2. Specification freeze and the MOQ quotation

This is the stage buyers most often underestimate. MOQ is quoted per project because it is driven by setup costs, not by volume pricing alone:

Cost driver	Why it sets a floor
Mould / tooling	Existing tooling is far cheaper than new tooling; a new geometry can require its own mould
Print setup	Laser programming and fixture setup are one-off per design
Packaging run	Custom bagging or racking has a minimum run
Sterilization batch	Irradiation is run in batches; a small order may be consolidated

This is why a serious supplier will not publish a single MOQ number and will instead ask for your specification first. Be cautious of a fixed MOQ quoted before anyone has seen the artwork or packaging requirement.

What to send at this stage

• Target format and dimensions
• Artwork file for the logo or print
• Barcode / QR content and placement
• Packaging requirement (individual bag, rack, bulk)
• Sterile or non-sterile
• Estimated annual volume, not just first order

Annual volume is the single most useful number you can provide — it lets the supplier recommend existing tooling where possible, which is the main lever on both MOQ and unit price.

3. Sampling and approval

Never go from drawing to production. The correct sequence is:

1. Pre-production sample made to your frozen specification.
2. Physical approval by you — check colour, print position and legibility, cap fit, and packaging.
3. On-instrument testing where the product interfaces with equipment (plates, strips, tips). Confirm fit and, for PCR, confirm Ct consistency rather than just that amplification occurred.

Approving a sample is what converts an estimate into a committed lead time. Skipping it is the most common cause of a project that “finishes on time” but produces product you cannot use.

4. Production and sterilization

Look for the production environment to be stated concretely:

• Manufacture in a 100,000-class cleanroom with automated injection moulding and assembly.
• Materials at the required grade — USP Class VI polypropylene, polystyrene or PET/PETG for consumables in contact with samples.
• Gamma irradiation to SAL 10⁻⁶ where sterile product is required.
• Release criteria addressing DNase, RNase and pyrogen contamination, with no mold-release agents or colour additives.

Colour additives deserve a specific note: if you request a custom colour, ask whether the masterbatch affects the release criteria. Additives are a legitimate concern in fluorescence-based assays.

5. Documentation

For each production batch, expect:

• CoA — sterility, endotoxin, cytotoxicity, RNase/DNase residues
• Third-party test reports — available per batch on request
• Certificate of origin and the trade documents your destination customs authority requires

Keep the CoA for each batch against the shipment, so a question raised months later can be traced to a specific production run.

6. Packaging and shipping

• Custom individual packaging is prepared as part of the production run.
• Shipment from the factory is by international courier, air freight or sea freight, chosen on volume and urgency.
• The method and estimated transit time are stated in the quotation, not decided after production.

Realistic timeline expectations

Stage	Typical duration
Specification freeze and quotation	Days, once artwork and volume are supplied
Pre-production sample	Depends on tooling; existing tooling is much faster
Sample approval	Your review time — the main variable
Production	Custom orders commonly quoted around 15 working days from approval
Sterilization + documentation	Within the production window
Shipping	Quoted separately by method

For stock items, none of the above applies: they are orderable from a single pack and typically ship in 1–2 working days.

Common mistakes

1. Requesting a quote without a specification. You will get a range, not a number.
2. Omitting annual volume. It is the main input to tooling decisions.
3. Skipping sample approval to save time, then discovering a print or fit problem after production.
4. Changing the specification mid-project. Any change after tooling or print setup restarts the cost calculation.
5. Assuming a custom colour is free of technical consequences.

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Frequently asked questions

What is the MOQ for custom lab consumables? It is quoted per project, because it depends on tooling, print setup, packaging run and sterilization batch. Provide the specification and estimated annual volume and it can be quoted precisely.

Can I order stock items in small quantities? Yes — stock items are orderable from a single pack with no minimum, typically shipping in 1–2 working days.

Can my logo be printed on the tubes? Yes, via laser-printed marking, which is permanent. Barcode and QR codes can also be applied, including multi-code formats combining a laser-etched Data Matrix, a side barcode and a human-readable number.

Can I get a sample before ordering? Yes. Trial samples are available, and for instrument-fit questions plates or strips can be sent for on-instrument testing before a production order.

How long does a custom order take? Custom orders are tracked end-to-end and the fastest realistic delivery is around 15 working days; the exact lead time depends on specification and quantity and is confirmed in the quotation.

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Note: The information on the scientific research products above is for reference only!

Short answer: choose in this order — (1) confirm the SBS footprint, (2) pick the skirt type based on whether a robot handles the plate, (3) pick volume and format (0.1 mL vs 0.2 mL; single tubes vs strips vs plates), (4) pick the sealing film based on whether you read fluorescence, and (5) verify cleanliness (DNase/RNase-free) and instrument fit by model.

Getting the order right matters, because the first two constraints eliminate most of the catalogue before price is even a factor.

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1. Start with the SBS footprint

SBS (Society for Biomolecular Sciences) defines the standard microplate footprint — outer dimensions and well positions. Two consequences:

• A plate that meets SBS will physically fit any SBS-compliant instrument.
• A plate that nearly meets SBS may still seat, but with uneven contact between wells and the thermal block. That shows up as inconsistent Ct values across a plate — you get data that looks plausible but is not reproducible.

SBS compliance is therefore non-negotiable, and it is the one specification worth verifying with the supplier’s own documentation rather than assuming.

2. Skirt type: what it is actually for

The skirt is the raised plastic edge around the plate. It is not cosmetic — it determines whether the plate can be handled by automation.

Skirt type	Best for
Non-skirted	Manual pipetting only; lowest cost; unsuitable for robotic grippers and many plate stackers
Semi-skirted	A middle ground — enough edge for many handlers, while still fitting instruments with tight clearances
Fully skirted	Automated workstations, robotic arms and plate stackers; the most rigid and the least prone to warping

Rule of thumb: if a robot touches the plate, use fully skirted. If the plate is handled by hand and the instrument has tight clearances, semi-skirted is usually the right compromise. Non-skirted is for manual, cost-sensitive work.

3. Volume and format

Plate well count

• 96-well — the default for most qPCR and endpoint PCR work.
• 384-well — for high-throughput screening and reagent-limited assays.

Tube format

• 0.1 mL — low-volume reactions; sits higher in the block and suits instruments designed for low-volume tubes.
• 0.2 mL — the most widely used size; the safe default.
• Single tubes — flexible, for ad-hoc or low-count reactions.
• 8-tube strips and 12-tube strips — the practical middle ground: fewer plastic items to handle than singles, less commitment than a full plate, and compatible with strip-cap formats.

4. Sealing: match the film to the readout

This is where a lot of avoidable failure happens. Films are not interchangeable:

• Optically clear qPCR films — required for real-time fluorescence. A translucent or aluminium seal will block or distort the optical path.
• Aluminium heat-seal films — excellent sealing for storage and endpoint work; not suitable where fluorescence must pass through.
• Breathable films — for cell culture and long-term low-temperature storage, where gas exchange matters.
• Low-temperature / heat-seal options — for workflows where the seal is applied under controlled heat.

Ask two questions: does light need to pass through it? and does gas need to pass through it? The answers determine the film.

5. Wall uniformity and heat transfer

For PCR tubes and plates, ultra-thin, uniform walls are the point of the product. Thicker or uneven walls change the rate at which heat reaches the reaction, which shifts Ct values and can make replicate wells disagree.

Uniform wall thickness is a manufacturing quality issue, not a design specification you can read off a datasheet — which is why the next section matters.

6. Instrument compatibility: verify by model

“Compatible with most real-time PCR instruments” is not a specification. The useful answer names models. Ask the supplier which platforms they have verified compatibility with, for example:

• ABI — 7500, QuantStudio
• Bio-Rad — CFX96
• Roche — LightCycler 480
• Eppendorf and other mainstream platforms

Then validate on your own instrument before committing to a volume order — see below.

7. Cleanliness: DNase/RNase-free is not optional

PCR is an amplification technique. Trace nuclease contamination destroys the result: DNase degrades template, RNase degrades RNA. For PCR consumables, require:

• DNase-free and RNase-free — stated as a release criterion, not a marketing phrase
• Pyrogen-free, typically endotoxin < 0.1 EU/mL
• No mold-release agents or colour additives, which can inhibit amplification
• Gamma irradiation to SAL 10⁻⁶ where sterile product is required

8. How to validate a new supplier without risk

The lowest-risk sequence:

1. Request free trial samples of the specific formats you use.
2. Ask for plates or strips to be sent for on-instrument testing — run them on your own instrument before any production order.
3. Compare Ct consistency across the plate, not just whether the reaction worked. A plate can amplify correctly and still be unusable if well-to-well variation is high.
4. Only then place a volume order, and keep the CoA for that batch on file.

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Frequently asked questions

Are BUNSEN PCR plates SBS standard? Yes — the 96-well and 384-well plates are manufactured to the SBS footprint in non-skirted, semi-skirted and fully skirted formats.

Which is better, 0.1 mL or 0.2 mL PCR tubes? It depends on reaction volume and instrument. 0.2 mL is the most widely supported default; 0.1 mL suits low-volume reactions and instruments designed for it.

Can I use an aluminium seal for qPCR? No. Real-time fluorescence has to pass through the seal, so an optically clear qPCR film is required. Aluminium seals are for storage and endpoint work.

Do BUNSEN PCR consumables work with ABI, Bio-Rad and Roche instruments? They are verified compatible with mainstream platforms including ABI (7500 / QuantStudio), Bio-Rad (CFX96) and Roche (LightCycler 480). Because heat-transfer behaviour depends on the instrument’s block, trial samples can be supplied for on-instrument testing before a production order.

Are the plates supplied sterile? PCR consumables are supplied DNase-free and RNase-free as a release criterion, with gamma irradiation to SAL 10⁻⁶ available where sterile product is required.

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Note: The information on the scientific research products above is for reference only!