A cryopreservation result is the product of many small decisions. The cooling rate, the cryoprotectant mixture, the vial, the thawing method and the assay all influence the outcome. A statement such as "post-thaw viability was 85%" is useless to another laboratory unless it is attached to those decisions. WIA-CRYO-010 therefore treats metadata as a first-class requirement. A record that cannot say what was frozen, how, with which chemistry and on which equipment cannot be reproduced, compared or submitted to a regulator.
This chapter walks through the descriptive blocks of a WIA-CRYO-010 v2.0 record: identity, researcher, sample, protocol, temperature profile, cryoprotectant, equipment, measurements, quality control, clinical and provenance information. It explains the reason behind each requirement as well as the rule itself.
The metadata burden has increased with each release. Each addition answers a recurring weakness in published cryobiology data.
| Version | Release | Metadata emphasis |
|---|---|---|
| v1.0 | 2023-06-01 | Experiment id, type (cell or tissue), researcher, date; initial and final temperature, cooling rate; cryoprotectant type and concentration; pre-freeze and post-thaw viability |
| v1.1 | 2023-12-01 | Organ and embryo types; ORCID; structured researcher block; multi-component cryoprotectants; sample size n; equipment model and calibration date; funding, keywords, related DOIs |
| v1.2 | 2024-06-15 | Sample block; protocol method; osmolality and pH; protocol deviations; clinical trial block; data classification; license and change logging |
| v2.0 | 2025-01-01 | Mandatory manufacturer, grade and preparation date for each cryoprotectant; required sample-temperature channel; replicate counts; controlled assay vocabulary; ultra_rapid method |
v1.1 accepted data from v1.0 through a migration tool, and v1.2 provided wia-cryo-migrate-v1.1-to-v1.2. Older records can therefore be brought forward by adding the missing fields instead of being discarded.
Every record opens with the standard and version declarations, followed by an experiment block. In v2.0 this block requires four elements:
id: unique, in the format CRYO-YYYY-NNN, for example CRYO-2025-001.type: one of cell, tissue, organ or embryo.title: a human-readable name for the study.date: an ISO 8601 date-time.The year-and-sequence identifier lets a laboratory's own numbering travel with the data. The type enumeration is more than a label. A cell suspension, a tissue slice and a whole organ differ in how cryoprotectant penetrates and in how viability is measured, so downstream tools use this field to decide which checks apply. Since v1.2, legacy date formats are deprecated and ISO 8601 is the only accepted form.
The nested researcher object carries name, orcid (format 0000-0000-0000-0000), institution and email. All four are required in v2.0, whereas ORCID was only recommended in v1.1. The reasoning is practical. Cryopreservation protocols are passed between laboratories, and when a result cannot be reproduced, the first need is a verifiable person to ask. Names are ambiguous, institutions change and e-mail addresses expire, but an ORCID persists.
The Phase 1 JSON-LD experiment schema extends this idea. It models a principalInvestigator as a Person with orcid and affiliation, and an institution as an Organization with a ror identifier from the Research Organization Registry. This ties both people and institutions to external registries rather than to free-text strings.
The sample block has four required fields: type, source, quantity and unit. The type is drawn from a controlled vocabulary, so spellings like "MSC", "hMSC" and "human mesenchymal stem cells" do not fragment a search. The SDK example uses human_mesenchymal_stem_cells with source bone_marrow, quantity 5000000 and unit cells.
These fields matter because freezing tolerance depends on the biological material. Cell type, tissue origin and cell number per vial all alter the optimum protocol. The Phase 1 experiment schema adds further descriptors under scientific: subjectType (CELL_CULTURE, TISSUE, ORGAN, ORGANISM, GAMETE, EMBRYO), species as a scientific name, sampleSize, replicates and controlGroups.
The protocol block starts with method, an enumeration of slow_freeze, vitrification, directional and ultra_rapid. The specification defines two of these in its glossary. Slow freezing is controlled-rate cooling that allows gradual cellular dehydration. Vitrification achieves glass-like solidification without ice crystal formation.
The choice determines how the remaining metadata is read. For slow freezing, the cooling rate is the critical quantity. For vitrification, cryoprotectant composition and the speed of passing through the glass transition dominate. A reviewer who sees the method first knows which numbers to examine. The protocol block also requires temperature_profile, cryoprotectant and equipment_settings objects, which the next sections describe.
Temperature history is the most distinctive metadata in this field. v2.0 requires the following of any profile:
sample_temperature for every point. The optional chamber_temperature must not replace it.The separation of sample and chamber temperature is deliberate. A controlled-rate freezer reports its chamber setpoint, but the sample lags behind it, and latent heat released at ice nucleation can briefly warm the sample. The excerpt below, taken from the SDK example, shows the shape of the data.
"temperature_profile": {
"unit": "celsius",
"sampling_rate": 1,
"data_points": [
{ "time": 0, "temperature": 37, "sample_temperature": 37 },
{ "time": 60, "temperature": -80, "sample_temperature": -79 },
{ "time": 120, "temperature": -196, "sample_temperature": -196 }
],
"statistics": {
"mean_cooling_rate": -1.02,
"temperature_uniformity": 0.95
}
}The statistics object summarises the run with a mean cooling rate in degrees per minute and a temperature uniformity score on a 0 to 1 scale. Long, densely sampled traces can be exchanged in HDF5, introduced in v1.2 for large time-series.
A cryoprotectant agent protects cells from cryoinjury, but its effect depends on exactly what was in the vial. The v2.0 specification therefore describes the mixture as a list of components. Each component has name, concentration, unit (percent_v/v, percent_w/v or molar), grade and manufacturer. A lot_number is recommended. The solution as a whole carries a required preparation_date and optional osmolality (mOsm/kg) and pH.
The composition must total 100%. The SDK example satisfies this with DMSO at 10% v/v, FBS at 20% v/v and culture medium at 70% v/v. The sum check catches transcription errors, and grade, manufacturer and lot capture reagent variability that often explains unexplained batch-to-batch differences. Osmolality and pH matter because an osmotic mismatch can damage cells before freezing begins.
The Phase 1 JSON-LD formulation schema goes further for reusable recipes. It separates permeatingCPAs from nonPermeatingCPAs, records CAS numbers and catalog numbers, and allows iceBlockers, additives, glassTransitionTemp and a Vitrification Quality Index under performanceMetrics. Formulations carry their own status of EXPERIMENTAL, VALIDATED or DEPRECATED.
The equipment_settings object records the instrument model, manufacturer and calibration_date, as in the example's CryoFreeze-3000 from CryoTech Inc. Calibration also appears in the quality_control block as the required equipment_calibration date. Version 1.1 introduced a rule that calibration must fall within 12 months of the experiment.
The requirement exists because a freezer whose probe has drifted produces a temperature profile that looks plausible but is wrong. Without a calibration date, nobody can judge whether the recorded cooling rate is trustworthy.
The measurements block requires pre_freeze_viability and post_thaw_viability, each between 0 and 100, plus assessment_timepoint and assessment_method. The fuller viability_assessment object adds these elements:
method: trypan_blue, flow_cytometry, MTT, ATP or live_dead_staining.timepoint in hours post-thaw.biological_replicates and technical_replicates, each at least 3.total_cells and viable_cells, with viability_percentage.The timepoint is important because early membrane-integrity assays can overestimate survival, since cells that will die by delayed-onset mechanisms still look intact shortly after thawing. The method matters because trypan blue and metabolic assays measure different things. The glossary defines viability as the proportion of cells or tissues retaining membrane integrity and metabolic function. Recording the assay and timepoint tells the reader which of those meanings applies.
The quality_control block holds the calibration date and an optional protocol_deviations array. Real freezing runs rarely go exactly to plan. A door opened, a nitrogen supply dipped, a thaw took longer than scripted. Recording these events beside the result lets a reader decide whether a low viability reflects the protocol or an accident, and prevents a failed run from being quietly dropped.
Clinical applications add a clinical_trial block. It requires a study_id and a patient object keyed by a study-specific identifier with no protected health information. Other elements include age_range, sex (M, F or O), consent_version, consent_date, irb_approval and a data_classification of public, restricted or confidential.
The privacy rules are strict:
Cryopreserved gametes, embryos and tissue bank material are especially sensitive, and sample age and storage can span years, so consent must remain traceable for as long as the specimen exists.
Provenance metadata completes the record. The Phase 1 schema groups irbApproval, fundingSource, keywords and relatedPublications (an array of DOIs) under metadata. From v1.2, the data license (CC-BY-4.0 is recommended) and version control with change logging also appear. These items support the FAIR principles named among the normative references: findable through keywords and identifiers, reusable through an explicit license and a documented origin.
Phase 1 requires WIA-CRYO-010 data to be expressed as JSON-LD. A shared @context and vocabulary give every field a defined meaning, and unit vocabularies are referenced through QUDT. A base wrapper carries @type, an @id of the form urn:uuid:{UUID}, a version and created and modified timestamps. Experiment records use @type CryoResearchExperiment.
An experiment's lifecycle.status moves through PROPOSED, APPROVED, PREPARING, IN_PROGRESS, ANALYZING, COMPLETED and ARCHIVED, with start, expected completion and actual completion dates. This lets a registry distinguish a planned study from a finished one, and an archived study from one still collecting data.
The following excerpt, trimmed from the SDK example, shows how the blocks fit together. A complete v2.0 record would also supply the remaining required fields discussed above, such as cryoprotectant manufacturer and the full measurement set.
{
"standard": "WIA-CRYO-010",
"version": "2.0",
"experiment": {
"id": "CRYO-2025-001",
"type": "cell",
"title": "Mesenchymal Stem Cell Cryopreservation",
"researcher": { "name": "Dr. Jane Smith", "orcid": "0000-0001-2345-6789" }
},
"sample": {
"type": "human_mesenchymal_stem_cells",
"source": "bone_marrow",
"quantity": 5000000,
"unit": "cells"
},
"protocol": { "method": "slow_freeze" },
"measurements": {
"pre_freeze_viability": 98.5,
"post_thaw_viability": 85.2
},
"quality_control": { "equipment_calibration": "2025-01-01" }
}Requirements are only useful if they can be checked. The specification lists several automatable checks:
| Check | Rule |
|---|---|
| Range | Viability values between 0 and 100 |
| Logic | Post-thaw viability not greater than pre-freeze viability |
| Composition | Cryoprotectant concentrations sum to 100% |
| Format | ISO 8601 dates, valid e-mail addresses, ORCID pattern, CRYO-YYYY-NNN identifiers |
| Replication | At least 3 biological replicates |
| Profile | At least 3 temperature data points |
The logic check deserves a comment. A thawed sample showing higher viability than before freezing usually signals a counting error or mismatched samples, not a gain in survival. The v1.2 quality targets, 98% field completeness, 99% passing validation and data entry within 24 hours, give laboratories a measurable standard for their own data practices.
JSON is the primary exchange format in UTF-8. XML serves regulatory submissions, CSV serves statistical analysis, and HDF5 carries large time-series. The v1.2 interface defines RESTful endpoints: POST /experiments, GET /experiments/{id}, GET /experiments/search and PUT /experiments/{id}. The TypeScript SDK wraps submission in a single call:
const result = await client.submitExperiment(experiment);
console.log('Validation:', result.validation);The returned validation outcome is the first place a laboratory learns that a required field is missing. Clinical metadata is meant to support FDA 21 CFR Part 1271, EU Directive 2004/23/EC and the HFEA Code of Practice, so complete records are valuable well beyond the original study.
The metadata in WIA-CRYO-010 asks a cryobiology record to answer the questions a skeptical colleague would ask. The record identifies who did the work, what was frozen, by which method, at what measured sample temperatures, in which exact solution, on a calibrated instrument, and how survival was judged. Clinical records add consent and privacy safeguards, and JSON-LD plus ORCID, ROR and DOI links connect them to the wider research record. The validation rules turn these expectations into checks that can run before a record leaves the laboratory.
The next chapter moves from descriptive fields to the measurement payloads themselves: how temperature series, cooling-rate statistics and viability results are structured and handled in detail, building on the identifiers and blocks established here.