Microencapsulation and nanowarming enables vitrification cryopreservation of mouse preantral follicles

Abstract

Preantral follicles are often used as models for cryopreservation and in vitro culture due to their easy availability. As a promising approach for mammalian fertility preservation, vitrification of preantral follicles requires high concentrations of highly toxic penetrating cryoprotective agents (up to 6 M). Here, we accomplish low-concentration-penetrating cryoprotective agent (1.5 M) vitrification of mouse preantral follicles encapsulated in hydrogel by nanowarming. We find that compared with conventional water bath warming, the viability of preantral follicles is increased by 33%. Moreover, the cavity formation rate of preantral follicles after in vitro culture is comparable to the control group without vitrification. Furthermore, the percentage of MII oocytes developed from the vitrified follicles, and the birth rate of offspring following in vitro fertilization and embryo transfer are also similar to the control group. Our results provide a step towards nontoxic vitrification by utilizing the synergistic cryoprotection effect of microencapsulation and nanowarming.

Cryopreservation of organoids: Strategies, innovation, and future prospects

“…For smaller systems like droplets, photothermal rewarming can achieve heating rates as high as 10 7• C per min, making it particularly suitable for ultrafast rewarming of small-volume biological samples such as mouse oocytes, zebrafish embryos, coral larvae, and stem cells [60,200,201] However, limited laser penetration necessitates combining photothermal rewarming with other techniques for more significant volume samples. Tian et al [202] successfully combined magnetothermal and laser rewarming, resulting in a substantial increase in heating rate and suppression of devitrification. This synergistic approach significantly enhanced cell survival and embryonic development rates.…”

“…Requires additional ice inhibition methods; Complex rewarming process; Unable to completely avoid ice crystal damage; [188,202] High-concentration vitrification Avoids ice crystal damage; Enables preservation of larger sample volumes;…”

“…Tian et al. [ 202 ] successfully combined magnetothermal and laser rewarming, resulting in a substantial increase in heating rate and suppression of devitrification. This synergistic approach significantly enhanced cell survival and embryonic development rates.…”

“…(C) Combining laser heating with magnetic field heating to achieve rapid rewarming of biological samples. (D) The temperature change curve and rewarming rate of different rewarming methods [ 202 ] Copyright 2022, Springer Nature. (E) Rapid rewarming of biological samples by applying a pulsed electric field.…”

Engineering Magnetic Nanoclusters for Highly Efficient Heating in Radio-Frequency Nanowarming

“…Magnetic nanoparticles have emerged as a promising platform for nanowarming, a technique that leverages these nanoparticles to generate heat under an alternating magnetic field, thereby facilitating rapid and uniform heating of cryopreserved biological samples. − Their potential to overcome the limitations of traditional convective rewarming methods has been demonstrated across tissues and organs, including rat hearts, livers, and kidneys. − While previous work mainly focused on establishing the fundamental principles, feasibility, and initial protocols for nanowarming, the work used commercially available iron oxide nanoparticle cores and rational optimization of intrinsic nanoparticle properties such as size, assembly states, and surface coating to boost their heating performance remains less investigated. − …”