DEV Community: Cryolab Global

Oocyte Vitrification: The Engineering Behind Egg Freezing (And Why Storage Infrastructure Matters More Than Most People Think)

Cryolab Global — Fri, 14 Aug 2026 14:38:12 +0000

This isn't a coding post. But for anyone interested in precision engineering applied to biology, oocyte vitrification is genuinely fascinating territory.

The core problem vitrification solves

Water crystallises when it freezes. Ice crystals are physically destructive to cell membranes. For decades, slow-cooling methods attempted to manage this by cooling eggs gradually while using cryoprotective agents to draw water out of the cell beforehand. The results were inconsistent: survival rates below 50 percent, significant damage, poor clinical outcomes.

Vitrification solves the ice crystal problem differently. Rather than managing the crystallisation process, it eliminates it. By dropping temperature faster than 15,000 degrees Celsius per minute, water molecules have no time to organise into a crystalline structure. Instead they transition directly from liquid to an amorphous glass-like solid. No crystals. No physical damage.

The engineering challenge: achieving that cooling rate reliably, in a clinical setting, on a biological sample loaded in less than one microlitre of solution, every time.

The storage engineering problem

Post-vitrification, eggs are held at -196 degrees Celsius in liquid nitrogen storage tanks. The engineering here is less glamorous but arguably more consequential.

A clinical-grade LN2 storage dewar is a double-walled vacuum-insulated vessel. The vacuum between the walls minimises heat transfer by conduction and convection. Performance depends entirely on vacuum integrity, which degrades over time through age, mechanical stress, and manufacturing variance.

If the vacuum fails, insulation performance collapses. Liquid nitrogen boil-off rate accelerates. Temperature rises above the critical -130 degree Celsius threshold (the glass transition temperature, below which all molecular motion ceases). Biological processes resume. Damage accumulates in stored samples before anyone notices.

For a clinical egg storage facility, this is not a theoretical failure mode. HFEA regulations require continuous LN2 level monitoring and alarm systems in all licensed UK facilities. Equipment decisions made at procurement have consequences measured in years.

The numbers

Post-warming survival rates for vitrified oocytes in experienced labs: above 90 percent consistently. NYU Langone outcome data: 70 percent live birth rate for women who froze before age 38 and thawed at least 20 eggs. UK FET cycles: 39 percent live birth rate per transfer cycle, all-time high.

Age at freezing is falling: from a mean of 36.9 to 35.0 years in one 8-year study of 4,659 cycles.

The warming engineering

Warming is as technically demanding as the freeze. The egg must pass through the -130 to 0 degree transition zone fast enough to prevent ice recrystallisation. Cryoprotective agents must be progressively diluted in a stepwise protocol while the cell rehydrates. Timing precision matters: an error that takes seconds to make can destroy an egg that survived years of storage without incident.

Full article here

How Long Can Embryos Be Stored? The Science Behind Cryogenic Preservation

Cryolab Global — Fri, 14 Aug 2026 13:35:56 +0000

This isn't a software engineering post, but it is a fascinating deep-dive into a field where precision engineering, biology, and regulatory compliance intersect in life-changing ways.

The short answer: at -196 degrees Celsius, biological time stops. Embryos stored at this temperature show no measurable degradation over time. The longest successful pregnancy from a frozen embryo involved one stored for 27 years.

The longer answer involves the glass transition temperature (-130°C, the threshold below which all molecular motion ceases), vacuum insulation engineering, UK HFEA regulatory limits, and the storage infrastructure that makes it all possible.

Key facts:

A 2020 study in Human Reproduction found no statistically significant difference in live birth rates between embryos stored for one year versus nine years. In the UK, the HFEA now permits storage up to 55 years in defined circumstances. Vapour phase storage (holding samples above the liquid nitrogen surface rather than submerged in it) has become standard practice to eliminate cross-contamination risk.

The engineering side of this is genuinely interesting. A clinical-grade liquid nitrogen storage dewar is a double-walled vessel with a vacuum drawn between the walls to minimise heat transfer by conduction and convection. Over time, that vacuum degrades. A dewar holding irreplaceable patient embryos needs monitoring, servicing, and periodic replacement across a potential 55-year storage period. The engineering decisions made when purchasing a storage tank in 2026 have consequences that extend to 2081.

Paul Hague, Director of Cryolab and a 40-year veteran of cryogenic equipment supply: "A liquid nitrogen storage tank is a promise. And in reproductive medicine, that promise has to hold for years, sometimes decades."

Full article: Read here

Cryolab at ESHRE 2026 and the International Symposium on Spermatology

Cryolab Global — Fri, 07 Aug 2026 08:36:56 +0000

Cryolab attended two of the most consequential events in reproductive medicine and sperm biology in 2026 - ESHRE in London in July, and the XVth International Symposium on Spermatology at the University of Birmingham the same month.

For a company that has operated at the intersection of IVF clinical practice and andrology science for over 40 years, both events matter for different reasons.

ESHRE 2026 - Stand D08, ExCeL London

ESHRE is the annual reference point for the European IVF community. Cryolab has exhibited at every ESHRE Annual Meeting since Bonn in 1985 - 42 consecutive meetings. At this year's ExCeL London event (5-8 July), Cryolab exhibited at stand D08, presenting the CryoStork dry shipper range, CryoNest liquid nitrogen storage vessels, controlled rate freezers, and cryogenic consumables to clinicians, embryologists, and procurement professionals from NHS trusts, private clinics, and research institutions.

Paul Hague on 42 consecutive ESHRE meetings:

"ESHRE has grown from a small gathering of specialists into the central forum for reproductive medicine in Europe. What has not changed in 42 years is the fundamental purpose: people who care about outcomes for patients, comparing notes, challenging assumptions, and raising the standard of what is possible."

International Symposium on Spermatology - University of Birmingham

The ISS meets every four years. The XVth edition (29 July to 2 August) was the first time the symposium has been held in the United Kingdom since it was founded in 1969. Cryolab attended as a sponsor, with particular relevance given the company's 40-year history of supplying andrology laboratories globally.

The four-day programme covered spermatogenesis and genetics, ejaculation and the fertilisation environment, sperm function, and broader questions in sperm biology. Chaired by Professor Jackson Kirkman-Brown MBE of the University of Birmingham.

The product range on display

CryoNest liquid nitrogen storage vessels

CryoStork V3 and V10 dry shippers

CBS DigitCool controlled rate freezers

CryoGPT for immediate technical queries:

Full range here

The Consumables Mistake That Puts IVF Samples at Risk

Cryolab Global — Thu, 06 Aug 2026 14:44:28 +0000

In an IVF laboratory, the equipment gets the attention. Storage vessels are specified carefully. Controlled rate freezers are calibrated. Dry shippers are verified before every transfer. And then the consumables order goes through on autopilot.

Cryocanes, cryosleeves, visotubes, and goblets are small, inexpensive, and ordered in bulk. They do not have service intervals. They are, in the language of laboratory procurement, consumables - implying that one is as good as another.

That assumption is wrong, and in a licensed clinical setting, it carries real consequences.

The chain of custody that most labs treat as afterthought

Every cryopreserved sample in an IVF laboratory passes through a chain of consumables before it reaches the storage vessel. A goblet holds the visotube or straw carrying the sample. The goblet loads onto a cryocane. The cryocane, protected by a cryosleeve, is suspended inside the vessel.

The failure modes are quiet: a cryosleeve that becomes brittle at -195.8 degrees C and cracks during retrieval. A goblet that does not seat correctly on the cryocane. A cryocane incompatible with the vessel's canister system, sitting at an angle and exposing samples to slightly warmer temperatures near the neck.

None of these failures announce themselves.

Cryocane material and size: not interchangeable

Aluminium cryocanes offer better thermal conductivity than stainless steel - relevant when the rate of heat extraction at the point of liquid nitrogen plunge affects freeze quality. Stainless steel offers greater mechanical rigidity for high-access environments.

Half-size cryocanes serve high-density storage configurations. Using a half-size cane in a full-size system creates canister fit problems that manifest as sample movement, labelling misalignment, and retrieval errors.

The cryosleeve failure nobody logs

At -195.8 degrees C, some PVC sleeve formulations lose flexibility and crack at handling stress points - the open end gripped during retrieval. A cracked sleeve means a compromised label. A compromised label in a liquid nitrogen vessel, where condensation forms instantly on retrieval, means a sample whose identity cannot be confirmed with certainty.

Biological sample sleeves maintain flexibility at cryogenic temperature and provide a labelling surface that remains legible after extended storage periods.

"The laboratories that get consumables right treat them as part of the storage system, not as a separate purchasing decision. A cryocane that does not fit the canister correctly, or a cryosleeve that fails at cryogenic temperature, does not just create a practical problem - it creates a traceability problem." - Paul Hague, Cryolab (40 years supplying IVF laboratories)

Goblet and visotube compatibility is not guaranteed

Goblet sizing varies between manufacturers. A goblet specified for one cane system may not seat correctly on a cane from a different supplier. Visotubes must be compatible with goblet dimensions to allow accurate visual inspection without opening the vessel.

Consumables compatibility must be verified - ideally by sourcing from a supplier who confirms that components are tested to work together as a system.

The practical fix

Select cryocane size based on vessel configuration. Verify canister compatibility. Specify cryosleeves for temperature performance, not unit price. Confirm goblet and visotube dimensional compatibility. Document the full specification in the quality management system.

Treat consumables as a specification decision rather than a purchasing decision.

Full article and consumables range here

Originally published at cryolab

The Lab Infrastructure Behind IVF Vitrification Success Rates

Cryolab Global — Fri, 31 Jul 2026 14:26:43 +0000

IVF vitrification looks deceptively simple on paper: dehydrate the cell, plunge to liquid nitrogen, store at -195.8 degrees C, reverse the process at thaw. In practice, four variables determine whether post-thaw survival sits at 82% or 97%.

The consumable system Matched vitrification kits -- where equilibration, vitrification, and warming solutions are from the same manufacturer and validated together -- consistently outperform mix-and-match approaches. Osmotic mismatch at thaw is cytotoxic.
Open vs closed carriers Open carriers achieve faster cooling rates. Closed high-security straws eliminate the cross-contamination pathway through shared liquid nitrogen. HFEA accepts both. For programmes treating patients with transmissible infections, closed systems are the appropriate default.
Protocol execution The vitrification solution exposure window is 60-90 seconds. Exceed it and cryoprotectant toxicity damages the cell. Miss it and the cell is insufficiently dehydrated for glassy-state transition. Audit survival rates per operator.
Storage vessel quality A narrow-neck vessel with a low static evaporation rate keeps the vapour phase stable during access events. A wide-neck vessel opened frequently in a busy lab creates repeated temperature excursions in the upper canister positions.

Full article here

Equipment Maintenance Protocols for Cryogenic Systems in Clinical Settings

Cryolab Global — Fri, 31 Jul 2026 13:45:23 +0000

If you work in biotech infrastructure, clinical lab management, or any environment where long-term biological sample storage is involved, the maintenance principles for cryogenic equipment are worth understanding - even if your work sits adjacent to IVF rather than inside it.
This post walks through the core maintenance and validation requirements for liquid nitrogen storage vessels, dry shippers, and controlled rate freezers in UK IVF laboratories. The source is a detailed Cryolab article covering HFEA compliance and best practice:
https://cryolab.co.uk/cryogenic-equipment-maintenance-validation-uk-ivf-laboratory/
The Core Problem: Silent Failure Modes
Cryogenic equipment tends to fail gradually. Storage vessels do not have moving parts to seize or belts to snap. What fails is the vacuum insulation layer - and it fails by degrading, not by breaking. The symptom is increased liquid nitrogen consumption, tracked against the vessel's rated static evaporation rate.
Performance monitoring approach:
• Record LN2 level at each fill or check
• Track against rated static evaporation rate (specified per vessel)
• Flag significant deviation for investigation
• Frost on outer wall = late-stage vacuum failure
By the time frost is visible on the outer wall, the vessel's performance has already substantially deteriorated. Regular consumption logging is the early warning system.
Dry Shipper Verification: Why Specs Are Not Enough
Published hold time figures for dry shippers are measured under controlled conditions. Actual hold time in service depends on:
• Age and condition of the vacuum insulation
• Ambient temperature during transit
• How many times the vessel is opened
• Thoroughness of the charging process
Verification protocol:
• Charge vessel to manufacturer specification
• Record time of charge completion
• Monitor with calibrated temperature probe or data logger
• Record time at which internal temperature exceeds threshold
• Compare against acceptable hold time for the transfer in question
Minimum frequency: annually, plus after any impact event.
Controlled Rate Freezer Calibration: Two Separate Exercises
Temperature calibration and profile validation are not the same thing.
Calibration - verifies that the instrument's sensor readings match a calibrated reference thermometer across the operational temperature range.
Profile validation - verifies that the executed cooling profile matches the specified protocol within defined tolerances.
Both require documentation: date, result, name of person performing the work, and calibration certificate reference for any reference instruments used.
Full clinical context and product-level guidance:

Validation Study Design: What the SpermScope vs Makler Study at Spermatology 2026 Gets Right Methodologically

Cryolab Global — Mon, 27 Jul 2026 14:04:29 +0000

The study presented by Dr Bryan Woodward of X&Y Fertility at the XVth International Symposium on Spermatology (University of Birmingham, 29 July to 2 August 2026) is worth examining on its methodological merits.

The reference samples came from UKNEQAS RS (Manchester University NHS Foundation Trust, UKAS-accredited against ISO/IEC 17043:2023), with pre-established target concentration values. That avoids the circular reference problem common in instrument validation - both instruments were tested against an independent, externally verified standard rather than against each other as mutual ground truth.

Results summary

SpermScope R squared vs UKNEQAS targets: 0.77
Makler R squared vs UKNEQAS targets: 0.68
Direct comparison between chambers: no significant difference (p greater than 0.05)
Both differed significantly from UKNEQAS targets (p less than 0.05)

Conclusion

The SpermScope could be used instead of the Makler, with a slightly higher correlation to externally validated target values in this study.

Full coverage including methodology and clinical implications: Cryolab study article

Cryogenic PPE in IVF Labs: The Technical Specifications That Determine Whether Staff Are Actually Protected

Cryolab Global — Thu, 23 Jul 2026 08:35:14 +0000

For anyone building clinical systems, digital checklists or training platforms for fertility medicine, understanding why cryogenic PPE specification is so technically specific helps you build tools that reflect clinical reality rather than generic health and safety templates.

The specification problem

Standard laboratory PPE is not rated for cryogenic work. This distinction is not a technicality. A nitrile glove at -195.8 degrees C provides no protection against liquid nitrogen contact. A standard polycarbonate safety goggle does not account for the pressure and velocity of a nitrogen splash the way a rated cryogenic face shield does.

Every item of cryogenic PPE has a specific temperature rating and a specific application context. A training system or digital checklist that simply records "gloves worn: yes" without capturing glove length and task type is not capturing the clinically relevant data.

The task-to-specification matrix

Cryogenic glove length maps directly to task type:

Wrist-length: surface handling, brief contact, vitrification procedures with controlled hand position
Mid-arm or elbow-length: reaching into working dewars to 20 to 30 centimetre depth
Elbow or shoulder-length: deep storage vessel access, neck depths of 40 centimetres or more

Face protection maps to liquid nitrogen in motion vs static:

Safety goggles: baseline for all work near cryogenic vessels
Full-face shield: any task involving active nitrogen transfer, vessel filling, dry shipper charging

A clinical checklist system that captures this level of task-specific PPE assignment is significantly more useful than a binary PPE confirmation field.

The oxygen depletion variable

Oxygen depletion is the environmental hazard that PPE cannot address. Liquid nitrogen venting displaces oxygen in enclosed spaces. The HSE threshold is 19.5% minimum oxygen concentration in workplaces. Cognitive impairment at sub-threshold concentrations occurs without the affected person noticing in time to self-evacuate.

An oxygen depletion monitoring system is an expected control in any HFEA-licensed UK IVF storage environment. Any digital safety monitoring system for IVF laboratories should include oxygen depletion alarm status as a tracked variable, not just temperature and liquid nitrogen level.

Full PPE range here
CryoGPT for lab equipment queries: cryolab.co.uk/cryogpt

IVF Lab Consumables: What the Supply Chain Decisions Actually Mean for Clinical Outcomes

Cryolab Global — Wed, 22 Jul 2026 15:13:35 +0000

If you work in health tech, clinical systems, or laboratory informatics, understanding why IVF consumable selection is so technically demanding helps you build better tools for the clinicians using them.

The traceability problem is a data problem

HFEA requires that every biological sample in a UK IVF laboratory can be positively identified at any point during a storage period that now extends to 55 years under the Health and Care Act 2022. The physical identification system — straws, visotubes, goblets, canisters, cryocanes — maps to a digital inventory system that must accurately reflect physical storage reality at all times.

A mismatch between physical state and digital record is not a minor data quality issue. It is a regulatory incident. If a straw label fails in storage (standard permanent markers do not hold at -195.8°C), the physical identifier is gone. If the digital record does not provide the failsafe, the sample may be unidentifiable.

The cold chain constraint

Vitrification reagents — the matched set of equilibration solution, vitrification solution and warming solution used in embryo cryopreservation — are temperature sensitive. They require cold chain integrity from manufacture to delivery. A supplier who cannot guarantee storage and delivery conditions is a failure point in the protocol.

Temperature excursion in a reagent that cannot be visually inspected for degradation is an invisible risk. Clinical outcomes data does not immediately flag it. Only consistent post-thaw survival rate monitoring over time would surface it — by which point the damage is historical.

Why standardisation matters at scale

CBS High Security Straws work for both sperm cryopreservation and closed-system vitrification. One format, one sealer calibration, one training protocol. In a lab where multiple embryologists handle multiple sample types across multiple shifts, format consistency reduces the error surface significantly.

This is the same principle behind any good API design — minimise the number of ways a consumer can use a system incorrectly.

Full product range here
CryoGPT for lab equipment queries: cryolab.co.uk/cryogpt

The Science Behind Sperm Survival: What Happens to Semen at 196 C

Cryolab Global — Wed, 15 Jul 2026 09:27:20 +0000

This article is cross-posted from the Cryolab knowledge base. Cryolab has supplied cryopreservation and semen storage equipment to IVF clinics, sperm banks, and biobanks for over 40 years.

Most people know that sperm can be frozen. Far fewer understand what that actually means at a cellular level — and why the storage vessel is as important as the freezing protocol itself.
Sperm cryopreservation has been practised since the 1950s. The first human birth from frozen sperm was reported in 1953. Seventy years later, semen storage tanks hold the genetic material of millions of men worldwide.

What Freezing Does to a Sperm Cell
A human sperm cell is approximately 50 micrometres long and contains very little cytoplasm — an advantage during cryopreservation, as less intracellular water means reduced ice crystal formation risk.
Without cryoprotective agents, ice crystals form within and around the cell at temperatures between 0 and −15°C, puncturing membranes and destroying motility. The acrosome — the cap that enables sperm to penetrate an egg — is particularly vulnerable.
Cryoprotective agents such as glycerol:

Enter the cell and displace intracellular water
Lower the freezing point of the remaining solution
Dramatically reduce ice crystal formation during cooling

The sample is then cooled at a controlled rate before transfer to a semen storage tank at −196°C.

Why −196°C Is the Critical Threshold
TemperatureBiological StateAbove −130°CActive molecular motion, cellular degradation possible−130°CGlass transition — biological processes cease−196°CComplete biological stasis — no metabolism, no degradation
Any temperature excursion above −130°C during storage or transport reactivates biological processes. A semen storage tank that allows LN2 levels to drop does not just create an administrative problem. It potentially destroys irreplaceable genetic material.

What Happens at Thaw
Sperm straws are warmed rapidly — typically in a 37°C water bath for 30 to 60 seconds. Rapid warming minimises time in the dangerous intermediate temperature zone where ice recrystallisation can occur.
A well-optimised freeze-thaw protocol in a properly maintained cryogenic storage vessel should recover 50 percent or more of pre-freeze progressive motility.
Lower recovery rates are a signal to review:

Cryoprotectant protocol
Cooling rate
Storage conditions — particularly the semen storage tank

The Storage Variable Most Clinics Underweight
Freeze protocol optimisation receives enormous attention in the andrology literature. Storage vessel selection receives comparatively little.
Temperature fluctuations during long-term storage — caused by inadequate holding time or poor vacuum integrity in the dewar — cause progressive damage to cryopreserved sperm. That damage manifests not at the point of thaw but in reduced fertilisation rates and embryo quality downstream. By the time it is visible, it has been accumulating for months or years.

How Long Can Sperm Be Stored?
The scientific answer: indefinitely. At −196°C, there is no measurable degradation over time.
The practical answer is governed by regulation. In the UK, the HFEA sets initial storage limits with provisions for extension. Successful pregnancies have been reported from sperm stored for over 20 years.
What matters is not the calendar. It is the consistency of storage conditions throughout that period.

Why the Liquid Nitrogen Tank Is the Most Overlooked Piece of Kit in an IVF Lab

Cryolab Global — Wed, 15 Jul 2026 09:03:42 +0000

This post is a cross-post from the Cryolab blog. Cryolab has supplied cryopreservation equipment to IVF clinics and biobanks for over 40 years.

Every IVF clinic obsesses over the freezing protocol. The vitrification kit. The warming solutions. The embryologist's technique.
But here is what keeps the most experienced cryogenic engineers awake at night: the tank.
The liquid nitrogen storage tank sits in the corner of every IVF laboratory, every sperm bank, every biobank on the planet. It does not beep. It does not flash. It does not demand attention. And that quiet reliability is exactly why it gets overlooked — until the day it fails.

What the Tank Is Actually Doing
At −196°C, biological time stops. A cryopreserved embryo stored correctly today could be transferred in twenty years and achieve a healthy live birth. That has already happened — multiple times, in multiple countries.
The liquid nitrogen tank is what makes that possible. Its job: maintain a stable cryogenic environment, without interruption, for as long as the samples inside it need to be stored.
One failure is not a laboratory incident. It is the loss of something that cannot be replaced.

The Four Mistakes IVF Labs Make

Choosing on price alone
Underestimating holding time
Ignoring vapour phase vs liquid phase storage
No continuous LN2 monitoring integration Holding time is particularly misunderstood. It is the number of days a tank maintains operating temperature without a top-up. Clinics with irregular LN2 delivery schedules, bank holiday closures, or out-of-hours emergencies need tanks built for the longest possible holding times. Vapour phase vs liquid phase matters for HFEA compliance. Most modern IVF programmes have moved to vapour phase storage to eliminate cross-contamination risk.

Specs to Evaluate Before Price
SpecificationWhy It MattersHolding timeDays at temp without top-upCanister configurationCompatibility with your straw/cane systemNeck diameterThermal efficiency vs accessVacuum integrityCore insulation performanceSupplier support11pm Sunday alarm response

The Bottom Line
The cryopreservation workflow receives intense scrutiny at the point of the freeze. The cryogenic freezer that holds those embryos for the next decade receives a fraction of that attention.
That imbalance is worth correcting.

→ Explore Cryolab's liquid nitrogen tank range
→ Biobanking storage solutions
→ Complete guide to cryopreservation

The Tech Behind IVF Labs: Cryogenic Equipment Explained

Cryolab Global — Thu, 09 Jul 2026 09:55:45 +0000

Most people think IVF is about doctors and operating theatres. The reality is that the outcome of every IVF cycle depends heavily on what happens in the laboratory, specifically on the precision of the cryogenic equipment used to freeze, store, and transport genetic material.

Here is a plain English breakdown of the core equipment stack.

Controlled rate freezers vs vitrification

Two approaches to cryopreservation. Controlled rate freezers cool samples on a programmable temperature curve, slow and precise. Vitrification is ultra rapid cooling, dropping samples to a glassy state before ice crystals can form. Both are used in clinical IVF. Vitrification has become the dominant method for oocytes and embryos.

Storage dewars

Cryogenic dewars hold samples at minus 196 degrees Celsius using liquid nitrogen. No electricity required for temperature maintenance, which removes power failure as a risk factor. The engineering challenge is minimising liquid nitrogen evaporation while maximising storage capacity and organisation.

Dry shippers

For transport, dry shippers are insulated vessels that hold liquid nitrogen in absorbent material, releasing vapour phase nitrogen to maintain ultra low temperatures without free liquid. CryoStork dry shippers from Cryolab are used by IVF clinics and sperm banks worldwide for specimen transport.

The consumables layer

On top of hardware sits a consumables layer. Vitrification straws (open or closed high security systems), cryocanes, goblets, canisters, and labelling systems. Every item must be quality assured and traceable. All Cryolab consumables are UKCA and CE marked, backed by ISO 9001 certification.

Bringing it together

Equipping an IVF laboratory requires a coherent approach where every link in the cryogenic chain, from freeze to storage to transport, maintains unbroken ultra low temperature. Cryolab has spent over 40 years helping UK fertility clinics build and maintain that chain.

Full equipment guide: https://cryolab.co.uk/ivf-lab-equipment-explained-first-freeze-long-term-storage