Microbank® is a ready-to-use cryopreservation system: ~25 porous beads per vial, each bead = one viable sub-culture. Validated by peer-reviewed studies at both -20°C (24 months, 41 NCTC strains) and -70°C/-80°C (10-year anaerobe viability, UK PHLS). It eliminates glycerol-stock freeze-thaw cycling, was used on NASA's 2020 Mars Perseverance Rover mission, and is cited as the preferred commercial method in Bailey & Scott's Diagnostic Microbiology and the ASM Manual of Clinical Microbiology.
Key Facts
- ~25 cultures per vial — remove one bead, the rest stay frozen and undisturbed.
- Validated at -20°C — Manchester Metropolitan University, 24 months, all 41 NCTC/NCPF reference strains viable from a single bead.
- 10-year anaerobe viability at -80°C — UK PHLS Anaerobe Reference Unit (Cardiff), 100/100 isolates.
- 3 peer-reviewed JCM publications — PMIDs 15004063, 16455912, 18701656.
- NASA Mars Perseverance Rover (2020) — flight-hardware reference for sample-return organism storage.
- CE Marked, ISO 13485:2016 — manufactured by Pro-Lab Diagnostics, Georgetown TX.
Overview
Pro-Lab Diagnostics' Microbank® is a ready-to-use cryopreservation system designed to simplify the long-term storage and retrieval of bacterial and fungal cultures. It comprises a unique cryovial filled with treated, porous ceramic beads suspended in a proprietary cryopreservative solution.
The system addresses three problems clinical microbiology labs have struggled with for decades: disorganized stock collections, contamination risk from repeated freeze-thaw cycling, and inefficient culture recovery. Microbank® was used during NASA's 2020 Mars Perseverance Rover mission to store reference organisms for analysis of Martian sample-return material — an extreme-conditions test case for a system already used by reference labs on every continent.
What is Microbank®?
Microbank® uses pre-treated porous ceramic beads instead of glass beads for cryopreservation. Each system includes color-coded vials (blue, light blue, red, green, yellow) with GS1 2D Datamatrix barcodes for sample identification and LIS integration. The cryopreservative is the same proprietary formulation that has been used in all three peer-reviewed validation studies published in the Journal of Clinical Microbiology.
The bead's porosity is the active ingredient: each bead acts as a tiny carrier surface that adsorbs organisms during inoculation. When a single bead is removed from the frozen vial and rolled across an agar plate, it deposits a viable inoculum — without ever requiring the master stock to be thawed.
How to Use Microbank® (6-Step Protocol)
The full IFU is included in every box (PL.170C Rev. 2023-04). At a high level:
- Inoculate the broth in the Microbank vial with a fresh pure culture. Aim for a McFarland 2.0 or denser suspension.
- Invert the vial 4–5 times to emulsify the organism into the beads. Do not vortex — vortexing damages the cryopreservative coating.
- Aspirate excess cryopreservative with a sterile Pasteur pipette, leaving only the inoculated beads.
- Store the inoculated cryovial in a freezer or liquid nitrogen (see storage temperatures below).
- Retrieve a single bead at the bench when needed, using the Microbank Scoop (PL.177) or a sterile needle.
- Return the vial immediately to the freezer — no thawing is required, and the remaining beads stay frozen and undisturbed.
Storage Temperatures & Viability
Most cryopreservation systems are validated at -70°C or -80°C only. Microbank® is one of the few with independent peer-reviewed viability data at -20°C — meaning a hospital lab without a ULT freezer can still use it within its labeled performance range.
| Temperature | Validated Duration | Source |
|---|---|---|
| -20°C | 24 months, 41 NCTC/NCPF strains | Manchester Metropolitan University, independent study |
| -70°C / -80°C | 10 years, 100/100 anaerobes viable | UK PHLS Anaerobe Reference Unit, Cardiff |
| -80°C | 10 years, 97.8% yeast / 98.6% mould recovery | Espinal-Ingroff et al., JCM 2004 (PMID: 15004063) |
| -80°C | 2 years, MRSA methicillin resistance maintained | Veguilla et al., JCM 2008 (PMID: 18701656) |
| Liquid N2 | Manufacturer-stated up to 25 years | Pro-Lab Diagnostics IFU |
Each vial yields up to 25 retrievals. The optional Cryoblock™ accessory (PL.155-1) keeps the vial cold at the bench during retrieval — extending working time by approximately 30 minutes without compromising the remaining beads.
Why Reference Laboratories Choose Microbank®
- UK PHLS Anaerobe Reference Unit — ~20,000 isolates archived; sampled at 5, 7, and 10 years with no decline in viability; 100/100 anaerobes viable at 10 years.
- UK Gonococcal Reference Laboratory — 98.6% recovery rate over 2,400 retrievals of 100 N. gonorrhoeae isolates over 24 months; all antigenic types represented.
- Nottingham University Hospitals NHS Trust — 3,500 clinical isolates, 94 genera, stored on Microbank®.
- University of Liverpool — 65,000 isolates archived at -70°C, some from 2000, still routinely resuscitated.
- Bestbion DX (Germany) — 24 German reference labs supplied via Bestbion since the early 2000s.
"The advantage of using the Microbank® system over other cryogenic systems is its commercial availability and the published evidence that supports its use." — UK PHLS ARU lead
Microbank® vs Glycerol Stocks
The traditional alternative — 30% glycerol-broth aliquots at -80°C — remains in use at many labs, but it suffers from a fundamental design problem: every sub-culture requires thawing the master stock. Each freeze-thaw cycle risks viability loss and phenotypic drift, and once a glycerol vial has been thawed it should not be refrozen without re-validation.
Microbank® eliminates this entirely. The Microbank Scoop or a sterile needle removes one bead at the bench; the vial closes again immediately and goes back into the freezer with the remaining beads completely undisturbed. The 6th edition of Bailey & Scott's Diagnostic Microbiology and the ASM Manual of Clinical Microbiology both cite Microbank® as the preferred commercial method over glycerol broth.
Manufacturing & Compliance
Microbank® is manufactured under ISO 13485:2016 quality-management certification at Pro-Lab Diagnostics. The product is CE Marked for IVD use and carries a UK Authorised Representative listing. Every vial carries a GS1 2D Datamatrix barcode — the only commercial bead system with this feature, allowing direct ingestion into any LIS without manual entry.
Trusted for over 35 years, with active research studies continuing to be published, Microbank® remains the most validated organism storage system in clinical microbiology.
Frequently Asked Questions
What is the Microbank® bead system?
Microbank® is a ready-to-use cryopreservation system from Pro-Lab Diagnostics. Each vial contains ~25 pre-treated porous beads in a proprietary cryopreservative. Bacterial or fungal isolates are inoculated into the vial, the cryopreservative is aspirated, and the vial is frozen. Each bead retains one viable sub-culture, so a single vial yields up to ~25 retrievals without freeze-thawing the entire stock.
How long can organisms be stored on Microbank® beads?
At -80°C: up to 20 years (manufacturer stated; UK PHLS ARU has 100/100 anaerobic isolates viable at 10 years). At -20°C: 1–5 years (Manchester Metropolitan University: all 41 NCTC/NCPF reference strains viable at 24 months at -20°C). For best long-term results, -70°C/-80°C is recommended.
How many sub-cultures can one vial provide?
Approximately 25. Remove one bead per sub-culture using the Microbank Scoop (PL.177) or a sterile needle — the remaining beads stay frozen and undisturbed.
Has Microbank® been used by NASA?
Yes — Microbank® was used in the 2020 NASA Mars Perseverance Rover mission to store reference organisms for analysis of Martian sample-return material.
How does Microbank® compare to glycerol stocks?
Glycerol stocks require thawing the master stock for every sub-culture, and each freeze-thaw cycle risks viability loss and phenotypic drift. Microbank® lets the bench technologist remove one bead without disturbing the rest of the vial. Bailey & Scott's Diagnostic Microbiology and the ASM Manual of Clinical Microbiology both cite Microbank® as the preferred commercial method over glycerol broth.
References
- Espinal-Ingroff A, Montero D, Martin-Mazuelos E. Long-term preservation of fungal isolates in commercially prepared cryogenic Microbank vials. J Clin Microbiol. 2004;42(3):1257-9. PMID: 15004063.
- Baker J, Jeffries D. An evaluation of two commercial systems for the maintenance and recovery of clinical isolates. J Clin Microbiol. 2006;44(4):1253-9. PMID: 16455912.
- Veguilla W, Bui-Thanh NA, Maslow JN, Eckersley AM. Comparison of long-term storage of staphylococci, including methicillin-resistant Staphylococcus aureus, using glycerol broth and the Microbank system. J Clin Microbiol. 2008;46(10):3494-7. PMID: 18701656.
For more information about Microbank®, contact info@pro-lab.us or visit the Microbank® product page to order online.