An open-hardware platform for conservation of amphibian genetic resources based on gelatin capsules.

Amphibian biodiversity is declining worldwide, and accessible cryopreservation tools are needed to support germplasm repositories, especially in low-resource settings. We developed a platform that integrates 3D-printed open-hardware components with gelatin capsules as containers for amphibian sperm cryopreservation, using Xenopus laevis as a model. We compared a 3D-printed platform (CryoKit) to a computer-controlled freezer and evaluated capsule thawing strategies. The CryoKit reached -80 °C faster than the computer-controlled freezer (4.0 vs. 6.6 min) and produced similar post-thaw viability (54% vs. 50%), forward motility (11% vs. 9%), and twitching movement (21% vs. 22%). Capsules showed comparable thermal performance to straws (5.5 vs. 4.3 min), and produced similar viability (37% vs. 38%), forward motility (5% vs. 9%), twitching (23% vs. 20%), and fertilization (16% vs. 37%). The dry-thawing method prevented capsule dissolution while preserving fertilization capacity. Our open-hardware designs and practical thawing protocol provide an accessible, reproducible approach to amphibian sperm cryopreservation suitable for resource-limited settings.