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Compact benchtop centrifugation The operating principle of this compact benchtop centrifugation unit is based on a miniature brushless DC motor driving the rotor to rotate at high speed, thereby generating a centrifugation force field far greater than gravitational force. This accelerates the sedimentation and stratification of components of different densities within the mixture, enabling highly efficient separation of trace amounts specimen within a compact footprint.

The physics of separation

By utilising inertial forces centrifugation in place of gravity, the settling process—which would otherwise take several hours under the influence of gravity—is completed in a matter of seconds to minutes, resulting in a several-hundred-fold increase in separation efficiency.

The formula for calculating the relative centrifugal force (RCF) is: RCF = 1.118 × 10⁻⁵ × r × (RPM)², where r is the rotor rotation radius (in cm) and RPM is the rotational speed ( The formula for calculating the force (RCF) is: RCF = 1.118 × 10⁻⁵ × r × (RPM)², where r is the rotational radius of the rotor (in cm) and RPM is the rotational speed per minute. This directly reflects the actual separation efficiency and serves as the core basis for standardising the experiment.

Components of different densities and particle sizes exhibit significant differences in their settling rates in the centrifugation force field: particles with higher density and larger particle size settle rapidly to the bottom of the tube to form a precipitate, whilst components with lower density remain in the upper layer to form a supernatant, thereby achieving stratification.

How a mini centrifuge is built

Drive system: Utilises a miniature brushless DC motor, accelerating to maximum speed in 13–20 seconds, with extremely rapid start-stop response and an operating noise level of ≤60 dB, making it suitable for deployment close to a desk.

Rotor system: Mostly tool-free, quick-release composite rotors, compatible with the full range of laboratory micro-volume consumables, including 0.2 mL PCR tube, 1.5 mL/2 mL microcentrifuge tube and other laboratory microvolume consumables across the entire range; some models can be adapted for use with 96-well plates PCR plate via adapters.

Safety control system: Features a built-in automatic imbalance detection module which automatically stops the machine and triggers an alarm when the weight difference between the symmetrical tubes exceeds the threshold; this works in conjunction with the electronic lid lock interlock to prevent safety risks caused by operation with an imbalance.

Chamber structure: Features a stainless steel sealed centrifugation chamber with no hygiene dead zones; after experiments, it can be wiped down directly with 75 per cent ethanol to prevent specimen cross-contamination.

How separation runs in practice

centrifugation Sedimentation mode: This is a mode commonly used in small benchtop centrifugation machines. The drum wall is solid, and the mixture rotates with the rotor; particles with higher density settle directly to the bottom of the tube. It is widely used in nucleic acid extraction, serum separation, and instantaneous centrifugation in PCR systems, amongst other applications.

Microfiltration mode‌: When used in conjunction with spin column and centrifugation, which contain filter media, a force drives the liquid through the filter membrane, whilst solid particles are retained on the membrane, enabling nucleic acid, adsorption and protein ultrafiltration and other micro-purification operations, serving as a core support mode for molecular biology experiments.

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PCR consumables get treated as commodities, but two decisions determine whether a run works: whether the plate physically and thermally fits your instrument, and whether the seal survives 40 cycles at 95 °C. Everything else is packaging.

Skirt style decides what the plate fits

• Non-skirted — the cheapest, and compatible with the metal block of traditional PCR instruments. It flexes, so it is a poor choice for robotic handling.
• Semi-skirted — fits the large majority of qPCR instruments and automated workstations. This is the practical default if you are unsure.
• Fully skirted — rigid, with a raised tab that robotic grippers can locate, which prevents misalignment during high-throughput handling. Also the most stable choice if the same plate is used as a storage index.

Material and well volume

Medical-grade polypropylene is the standard because it is thin-walled and thermally uniform. Thin walls matter more than they sound: they transfer heat faster, and a well-made thin-walled plate cycles roughly 30 % faster than a thick-walled one, which shortens the run and reduces non-specific amplification.

Choose 96-well for routine work and 384-well only when you genuinely need the throughput — the working volume drops and pipetting tolerance becomes tighter. Well volume must match the instrument’s thermal module: 0.1 mL and 0.2 mL formats are not interchangeable.

Biosafety labels that matter

Confirm the plate is stated as DNase-free, RNase-free and pyrogen-free. On a qPCR plate these are not marketing terms: exogenous nucleic acid produces false positives, and nuclease contamination causes Ct drift that looks like a biological effect and is not.

Matching the sealing film to the application

The film exists to stop evaporation and contamination, but the wrong film can also block the optics or fail at temperature. Match it to the run, not to what is in the cupboard.

Application	Film type	What it must do
Standard PCR	PP adhesive or aluminium foil heat seal	−40 to 120 °C, hold pressure through 95 °C cycling
qPCR	Optical pressure-sensitive film	Transmission above 90 %, low autofluorescence
Storage at −80 °C	Thickened adhesive film	Very low water-vapour transmission, no embrittlement
Automated workstations	Heat-seal film	Thickness tolerance ≤ ±0.02 mm for automated sealers
Culture-adjacent PCR	Breathable film	Gas exchange without spillage or cross-contamination

A sealing procedure that survives thermal cycling

1. Prepare the bench. UV the work surface for 30 minutes and wear powder-free gloves. Reseal the bag immediately after removing one film — the rest of the pack has to stay nuclease-free.
2. Apply at an angle. Peel the backing along the tangent, align one end with the plate edge, and smooth the film down at about 30° so you are pushing air ahead of the adhesive rather than trapping it.
3. Do not touch the adhesive. Contact anywhere on the glue layer is how bubbles and creases start.
4. Press evenly. Using a smooth-edged applicator or card, press twice horizontally and twice vertically, working the edges and the gaps between wells. Firm, not brutal — excessive pressure pushes liquid out of the wells.
5. Inspect every well. No gaps at the edge, no creases across the surface.
6. Let it set, then spin. Leave the sealed plate for 10 minutes so the adhesive bond strengthens, then brief-centrifuge at 500 ×g for one minute to bring liquid and bubbles down before the run.

Common failure modes

• Film lifting at one corner after 30 cycles — usually a plate that was not dry at the rim, or the wrong film for the temperature.
• High fluorescence background in qPCR — an opaque or high-autofluorescence film instead of an optical one.
• Film delaminating in the freezer — an adhesive film not rated for −80 °C.
• Evaporation from edge wells — an incomplete seal that only shows up in the outer columns.

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The BUNSEN BUNSEN 96-well round-bottom deep well plate is a specialist laboratory consumable designed for high-throughput experiments. Its key advantage lies in the combination of a round-bottom design and a large-volume structure, which ensures both efficient sample processing and experimental stability.

What these plates are for

High-throughput specimen storage ‌: Can replace standard 1.5 mL tubes centrifuge tube, allowing for the neat storage of samples such as DNA, RNA, protein substances and compounds, thereby significantly saving storage space in -80°C freezers and facilitating specimen batch management of collections.

Molecular biology experiments: These are core consumables for experiments such as automated magnetic bead-based nucleic acid extraction, plasmid extraction, NGS library preparation and immunoprecipitation, supporting high-throughput operations throughout the entire process—from lysis to washing and elution.

Drug R&D Screening: Used for the storage, dilution and dispensing of compound libraries, supporting experiments such as high-throughput drug activity screening, siRNA library screening and hybridoma cell screening, thereby significantly improving screening efficiency.

Sample preparation procedure: Working in conjunction with multi-channel pipettes or automated equipment, this system enables the batch processing of protein preparation steps—including precipitation, liquid–liquid extraction and solid-phase extraction. Following preparation, samples can be fed directly into a liquid chromatography autosampler, eliminating the need for tedious operations such as transferring samples between vials.

Suspension cell and microbial culture: The round-bottomed design facilitates the growth of suspension cells, bacterial culture and subculturing; it ensures uniform mixing during shaking, thereby preventing dead zones residue.

Design and performance

Exclusive round-bottom design: The U-shaped round-bottom structure promotes the efficient resuspension of sedimented cells or magnetic beads, ensuring uniform mixing during shaking and incubation, whilst eliminating the sharp corners found in V-bottom designs that are prone to residue liquid leakage; it is also compatible with the vast majority of pipette tips and automated liquid handling probe.

Material and Resistance Properties: Manufactured from medical-grade polypropylene (PP), it is resistant to acids, alkalis, alcohols, DMSO and most other organic solvents. It can withstand prolonged exposure to temperatures ranging from -80℃ to storage, and is also suitable for high-temperature, high-pressure sterilisation at 121℃ sterilized.

Compatible with high-throughput and automated systems: The entire plate can process 96 samples simultaneously; its dimensions strictly comply with the ANSI/SBS international standard, enabling seamless integration with liquid-handling workstations, robotic arms, multi-channel pipette guns and other equipment to achieve a fully automated experimental workflow.

Biosafety assurance: Manufactured in a Class 100,000 cleanroom; third-party testing confirms the product is free from DNase, RNase, pyrogen-free, endotoxin-free; available in two versions—gamma-irradiated sterilized and non-irradiated sterilized—to meet sterile experimental requirements.

Flexible sealing solutions: Supports a variety of sealing methods, including heat-sealable film (excellent airtightness, suitable for long-term cryopreservation), silicone gaskets (permeable for sampling) and specialised snap-on lids (convenient for repeated opening and closing), to suit different experimental scenarios.

Excellent mechanical strength: it can withstand forces of 3,000–4,000 g centrifugation without breaking or deforming; the sheet is free from bubbles, streaks and liquid leakage, the wall thickness of the holes is uniform, and specimen the distribution is highly consistent.

Note: The product information above is for reference only!

BUNSEN BUNSEN offers a product range of over 10,000 items, which are widely used in research institutions, central laboratories and the field of molecular biology. The company’s extensive product range not only meets the specific requirements of R&D clients regarding product variety and packaging, but also caters to the comprehensive needs of manufacturing enterprises at every stage, from small-scale and pilot-scale trials through to large-scale production.

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15ml centrifuge tube is a staple consumable in the fields of biopharmaceuticals, chemistry and scientific research. Thanks to its moderate capacity, high compatibility and safe, stable performance, it is suitable for the vast majority of routine experimental scenarios, ranging from cell culture to molecular testing.

Cell biology

The 15 ml centrifuge tube is a frequently used consumable in cell-related procedures and is suitable for the vast majority of standard cell processing workflows:

Collection and concentration of cell suspensions: After pancreatic enzyme digestion of adherent cells, centrifuge the suspension directly at a low speed of 1000–1500 rpm centrifugation, replace culture medium or resuspend the cells to avoid the risk of contamination from repeated aliquot use of 1.5 ml tubes.

sterile System operation: DNase/RNase-free The pyrogen-free sterilized variant can be used directly in intermediate steps of cell passaging, primary cell isolation and immune cell culture, and is compatible with standard rotors for the vast majority of benchtop centrifugation machines.

Mild specimen Protection: U-shaped base centrifugation Cell sediment at the back is distributed in a thin layer and is not excessively compacted by the pointed base structure, significantly reducing mechanical damage during resuspension and better maintaining cell viability.

Molecular biology

15ml centrifuge tube We undertake end-to-end processing for small and medium-sized specimen:

protein Purification and processing: Following on from protein crude extraction and antibody purification, separation of the supernatant from immunoprecipitation, buffer elution and other steps; some ultrafiltration units with a 15 ml capacity centrifuge tube can also directly achieve protein rapid concentration by a factor of 25–50.

enzyme Preparation of reaction mixtures: suitable for medium-scale PCR systems; enzyme preparation of premixes to facilitate reactions and brief incubation; the clear graduations on the tube body facilitate rapid volume adjustment.

Sample collection and transport

In testing and biological specimen library work, 15 ml centrifuge tube is the tool of choice for batch specimen pre-processing:

specimen Separation: Directly performs the separation of plasma and blood cells from blood specimen, serum separation, and the precipitation of impurities in urine, cerebrospinal fluid and other fluids specimen, suitable for standard clinical centrifugation conditions of 3000–5000 x g centrifugation.

specimen Short-term storage: PP material can withstand temperatures as low as -80°C; the markings on the walls of the frosted tubes will not become blurred or peel off even after repeated freeze-thaw, thus preventing specimen confusion.

Multiple batches specimen aliquot : Batch aliquot culture medium, buffer, test reagents; the scale error on the tube body is controlled within ±2 per cent, enabling rapid quantification without the need for an additional measuring cylinder.

Chemistry and general lab support

In addition to biology experiments, it also meets a wide range of basic requirements for standard chemistry experiments:

Handling of corrosive reagents: High-purity PP material is resistant to corrosion by the vast majority of acids, alkalis and common organic solvents, and is used for the temporary storage, mixing and low-speed centrifugation purification of small to medium volumes of chemical reagents.

General-purpose specimen centrifugation Centrifugation: Used for the precipitation of impurities in environmental water samples, the separation of layers in soil leachates, and phase separation following the extraction of small-molecule compounds; suitable for standard centrifugation centrifugation forces of 7500xg or higher.

Universal compatibility with laboratory consumables: the standard outer diameter is compatible with rotors for almost all brands of benchtop centrifugation centrifuges, eliminating the need for additional adapters for specialised equipment and significantly reducing the cost of purchasing laboratory consumables.

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A 10 mL round-bottom tube and a 10 mL conical-bottom tube hold the same volume. They are not interchangeable, because the shape of the base decides what the tube is good at: one is built for volume and force, the other for recovering a pellet.

The difference is the base

A round base spreads stress evenly, so it tolerates higher g-force and larger volumes without cracking. A conical base concentrates solids into a tip, so you can pipette off supernatant without disturbing what you want to keep. Everything else — caps, material, graduations — is secondary to that one geometric choice.

Round-bottom, screw cap: volume and force

With a smooth base and uniform wall stress, round-bottom tubes tolerate higher centrifugation forces. That makes them the right choice for density-gradient work and for spinning down large sample volumes where a conical tube would concentrate everything into a tip you cannot easily resuspend.

The wide base also helps in less obvious ways. Solids are less likely to lodge in a corner, so cleaning is easier, and mixing is more effective because there is no dead zone at the bottom.

In PP they autoclave at 121 °C, and the one-piece design including the cap makes them convenient for routine biochemistry, batch pre-treatment of environmental water samples, and temporary storage. They also handle −80 °C, so short-term cryopreservation of standards and reagents works without extra sealing hardware.

Conical bottom: pellets you can actually see

The pointed base does one job extremely well: it collects the pellet at a single point. For nucleic acid purification, protein precipitation and cell pelleting, that concentration is the difference between recovering most of your sample and losing it against a large flat surface.

It also makes aspiration cleaner. The pipette tip can reach the supernatant above a compact pellet without dragging through it, which is what you want for cell culture work, microorganism collection and isolation from clinical or environmental samples.

The screw cap with an internal gasket seals harder than a push cap, so conical tubes are the better choice for extracting or transporting volatile reagents and for sample shipment where the seal has to hold for days.

The tip is also useful at the bench: it fits into narrow openings, so liquid can be drawn out of the tube directly, which suits assays and micro-chemical work where recovery of a small volume matters.

Side by side

	Round-bottom, screw cap	Conical bottom
Best at	Volume, high g-force, mixing	Pellet recovery, clean aspiration
Weak at	Recovering small pellets	Very high g-force, large-volume mixing
Typical use	Density gradients, water samples, reagent storage	Nucleic acid and protein prep, cell pelleting
Seal	Good	Better — gasket screw cap

Choosing in practice

If the experiment ends with “remove the supernatant and keep the pellet”, use conical. If it ends with “keep the liquid” or “spin a large volume fast”, use round-bottom. If you are storing rather than separating, round-bottom gives you more usable volume for the same tube length, and the flat base stands up on its own.

The common mistake is buying one type for the whole lab to simplify ordering. It works until someone tries to pellet 10⁶ cells in a round-bottom tube and wonders where the pellet went.

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Choosing a disposable culture dish comes down to three things: the material, the size, and how it was sterilised. Get those right and the rest — surface treatment, stacking, packaging — usually sorts itself out.

Material: polystyrene is the default

Polystyrene (PS) is the standard for a reason. It is highly transparent, has a smooth surface that is easy to read under a microscope, and most dishes receive a TC (tissue culture) hydrophilic treatment that makes it suitable for adherent cell culture and routine microbiology at a reasonable price.

Its limits are absolute: PS does not tolerate ethanol, acetone or other organic solvents, and it cannot be autoclaved. If the experiment involves either, you need a different material.

Polypropylene and the speciality plastics

Polypropylene (PP) is chemically resistant, survives 121 °C autoclaving, and is tough enough that it rarely cracks in handling. It suits organic solvents, work that needs high- or low-temperature storage, and suspension culture. The trade-off is optical quality — PP is noticeably hazier, so it is a poor choice for high-magnification observation.

Beyond those two, materials become purpose-specific. Polycarbonate (PC) offers high toughness with good clarity and appears in optical work. Cycloolefin copolymer (COC) has low protein adsorption and high light transmission, which makes it the right answer for fluorescence imaging and other high-sensitivity detection. Both cost considerably more, so specify them only when the assay needs them.

Standard sizes and working volumes

Round dishes follow a small number of standard diameters. The working volume matters as much as the diameter: too little medium and the culture dries at the edges, too much and gas exchange suffers.

Diameter	Growth area	Working volume	Typical use
35 mm	~8 cm²	2–3 mL	Small-scale observation, single-cell cloning
60 mm	~21 cm²	4–6 mL	Routine passaging, preliminary drug screening
90 mm	~64 cm²	15–20 mL	Microbial colony counting, settle plates
100 mm	~55 cm²	10–15 mL	Larger-scale expansion, virus culture
150 mm	~145 cm²	25–30 mL	High-throughput culture, strain expansion

Multi-well plates (6-, 12-, 24- and 96-well) and square dishes cover the cases where you need many parallel conditions in one footprint.

Sterilisation: gamma versus ethylene oxide

Gamma irradiation suits almost every plastic used for dishes, penetrates the packaging, leaves no residue and does not degrade the polymer at normal dose levels. It is the default for cell culture.

Ethylene oxide (EO) is reserved for materials that cannot take gamma. It works, but you must confirm that residual EO is within the limits set by the relevant standard — residue that stays on the plastic can affect cell growth just as surely as contamination would.

What the labels should say

A compliant single-use dish carries a sterility assurance level (SAL) of 10⁻⁶, meaning a theoretical probability of one non-sterile unit in a million. For cell culture you also want DNase-free, RNase-free and pyrogen-free stated on the certificate, not just on the box — those three are what stop a dish from quietly changing your results.

Choosing in one minute

1. Adherent cells, routine work → PS, TC-treated, gamma sterilised.
2. Organic solvents or autoclaving → PP.
3. Fluorescence or low-adsorption work → COC.
4. Pick the diameter from the growth area you need, then set the medium volume from the table above.

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PETG square bottles

Feature 1: High transparency

PETG is a highly transparent plastic with a translucent ice-blue undertone that is in line with global trends, and its surface is exceptionally smooth. It boasts excellent optical properties, a high-gloss surface and low turbidity; its light transmittance is close to 90 per cent, which is very similar to that of acrylic (PMMA) and superior to that of polycarbonate (PC).

High impact resistance

Low-temperature performance

The physical and mechanical properties of PETG remain virtually unchanged at low temperatures, and it is one of the few environmentally friendly plastic materials available to date. It is considered an environmentally friendly material because, when burnt, it produces only CO₂ and water, thereby helping to protect the natural environment; furthermore, containers made from it are non-cytotoxic and pyrogen-free.

Bottles with an integrated straw tube

Highly adaptable transfer caps, standard Luer connectors and TPE thermoplastic tubing, all produced using single-piece injection moulding, provide sterile transfer solutions for the pharmaceutical, biotechnology and laboratory sectors, enabling the sealed transfer of liquids.

PET square bottles

In fact, PETG is a type of PET; both are classified as ‘No. 1’ in the plastic classification system. Compared with PET, PETG simply replaces the hydroxyl group on the ethylene glycol chain with CHDM.

Consequently, both share very similar material advantages:

1. It has excellent mechanical properties, with an impact strength 3 to 5 times that of other films, and good resistance to creasing.

2. Resistant to oils, fats, dilute acids, dilute alkalis and most solvents.

3. It can be used within a temperature range of 55–60 °C; it can withstand temperatures of up to 65 °C for short periods and temperatures as low as –70 °C, and its mechanical properties are only minimally affected by high or low temperatures.

4. It has low permeability to gases and water vapour, whilst offering excellent resistance to gas, water, oil and odours.

5. It is highly transparent, blocks UV rays and has a good gloss.

6. As the most affordable engineering plastic, PET offers excellent value for money.

HDPE bottles

HDPE stands for high-density polyethylene

1. As the polymerisation of ethylene is catalysed, very few branches are formed, resulting in a highly robust and dense structure that enables it to be used at 105 °C.

2. High-density polyethylene resin is milky white in colour and has poor transparency.

3. High-density polyethylene resin has good stiffness, tensile strength, mechanical strength and heat resistance; however, products made from it may only be used at temperatures not exceeding 80 °C.

4. High-density polyethylene products also offer good electrical insulation, toughness and cold resistance, and can withstand low temperatures of down to –80 °C in cold storage.

5. It has extremely low water absorption (no more than 0.03 per cent) and good chemical stability.

Note: The product information above is for reference only!

BUNSEN An explanation of: PET, PETG and HDPE reagent bottle ? BUNSEN The company’s product range now exceeds 10,000 items and is widely used in research institutions, central laboratories, molecular biology and other scientific fields. The company’s extensive product range not only meets the specific requirements of R&D clients regarding product variety and packaging, but also caters to the comprehensive needs of manufacturing enterprises at every stage, from small-scale and pilot-scale trials through to large-scale production.

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