Overview
EN ISO 29701:2010 (ISO 29701:2010) - "Nanotechnologies - Endotoxin test on nanomaterial samples for in vitro systems - Limulus amebocyte lysate (LAL) test" - defines how to apply the Limulus amebocyte lysate (LAL) test to nanomaterial samples. The standard covers LAL testing of nanomaterials dispersed in aqueous media (e.g., water, serum, reaction medium) and media incubated with nanomaterials (typically at 37 °C). It is focused on samples intended for cell‑based in vitro biological test systems, and notes that methods can be adapted for parenteral animal administration.
Key topics and requirements
- Scope and definitions: clear terminology for endotoxin (LPS), endotoxin units (EU), LAL, coagulogen/coagulin and test sample types.
- Pre-test considerations: storage and handling of nanomaterials and containers to minimise contamination; laboratory environment controls.
- Test sample preparation: guidance on preparing aqueous dispersions and aqueous extracts, dispersion and extraction methods, concentration and storage of test samples.
- Test methods and validation: principles and selection of LAL test formats (gel‑clot, chromogenic/endpoint photometric, turbidimetric/kinetic approaches are included in informative annexes), plus validation requirements and use of inhibition/enhancement controls.
- Interference assessment: identification of potential nanomaterial interferences with LAL assays and controls to detect inhibition or enhancement.
- Results and reporting: assessment of endotoxin levels (in EU/mL) and recommended test report contents to support interpretation for in vitro systems.
Practical applications
- Toxicity screening and biocompatibility: ensure endotoxin contamination does not confound cell‑based assays (macrophage and other cytokine‑responsive cells are highly sensitive to LPS).
- Quality control for nanomaterials: routine endotoxin testing of aqueous dispersions used in research, safety testing or preclinical studies.
- Regulatory and safety assessment: supports reproducible endotoxin measurement for laboratories performing in vitro biological tests and for adapting methods for parenteral product testing.
Who should use this standard
- Nanomaterials researchers and laboratories performing in vitro toxicology
- Biocompatibility and preclinical testing labs
- Medical device and nanotechnology product manufacturers managing endotoxin risk
- Quality assurance and regulatory scientists validating LAL assays for nanomaterial samples
Related standards and context
- LAL-based bacterial endotoxin test (BET) methods are described in pharmacopoeias and regulatory guidance; ISO 29701 applies those principles specifically to nanotechnologies (prepared by ISO/TC 229). Informative annexes in the standard provide practical methods (gel‑clot, photometric, kinetic) and examples of interferences to aid implementation.
Keywords: EN ISO 29701:2010, ISO 29701, LAL test, endotoxin testing, nanomaterials, in vitro, Limulus amebocyte lysate, LPS, endotoxin unit.
