Diamour®, a newly vitrification device for human blastocysts, provides the same efficient perinatal outcomes as the commonly used Cryotop®.

OBJECTIVE: The purpose of this study was to investigate the effectiveness of Diamour®, a newly developed vitrification device, for the ultra-rapid frozen storage of human blastocysts. MATERIALS AND METHODS: Surplus blastocysts obtained using assisted reproductive technology at our clinic during a 2-year period (2018-2019) were assigned for vitrification with the Diamour® device in 2019 or a comparator device in 2018. We retrospectively compared outcomes (clinical pregnancy rate, abortion rate, live birth rate, and perinatal outcomes) between the two vitrification devices. RESULTS: We obtained 228 blastocysts from 178 patients, and 118 blastocysts were cryopreserved using the Diamour® vitrification device and the other 110 were cryopreserved using a Cryotop®, the comparator device. We found no significant difference between the Diamour®-vitrified and comparator-vitrified blastocysts in clinical pregnancy rate (32.2% vs. 30.9%; p = 0.83), abortion rate (17.0% vs. 9.1%; p = 0.08), and live birth rate (25.4% vs. 26.4%; p = 0.87). The Diamour®-vitrified blastocysts yielded 30 live births, and the comparator-vitrified blastocysts 29. The two devices yielded no significant difference in birth weight (Diamour®: 3049 ± 337 g, comparator: 3008 ± 340 g; p = 0.65) and congenital abnormalities, with just 1 case (cleft lip) noted with Diamour® vitrification (p = 0.33). The devices also showed no significant differences in the incidence of gestational diabetes mellitus, hypertensive disorders of pregnancy, placenta previa, preterm birth, macrosomia, low birth weight, and delivery method. CONCLUSION: The Diamour® device achieves outcomes similar to those of the currently widely used Cryotop® device for clinical pregnancy with frozen-thawed human blastocysts.

Efficient vitrification of mouse embryos using the Kitasato Vitrification System as a novel vitrification device.

BACKGROUND: Currently, the cryopreservation of embryos and oocytes is essential for assisted reproductive technology (ART) laboratories worldwide. This study aimed to evaluate the efficacy of the Kitasato Vitrification System (KVS) as a vitrification device for the cryopreservation of mouse embryos to determine whether this novel device can be adapted to the field of ART. METHODS: In Experiment 1, blastocysts were vitrified using the KVS. Vitrified blastocysts were warmed and subsequently cultured for 72 h. In Experiment 2, 2-cell-stage embryos were vitrified using the KVS, and vitrified embryos were warmed and subsequently cultured for 96 h. In Experiment 3, we evaluated the in vivo developmental potential of vitrified 2-cell-stage embryos using the KVS, and in Experiment 4, we evaluated the cooling and warming rates for these devices using a numerical simulation. RESULTS: In Experiment 1, there were no significant differences between the survival rates of the KVS and a control device. However, re-expanded (100%) and hatching (91.8%) rates were significantly higher for blastocysts vitrified using the KVS. In Experiment 2, there were no significant differences between the survival rates, or rates of development to the blastocyst stage, of vitrified and fresh embryos. In Experiment 3, after embryo transfer, 41% of the embryos developed into live offspring. In Experiment 4, the cooling and warming rates of the KVS were 683,000 and 612,000 °C/min, respectively, exceeding those of the control device. CONCLUSIONS: Our study clearly demonstrates that the KVS is a novel vitrification device for the cryopreservation of mouse embryos at the blastocyst and 2-cell stage.

Cyclopolymerization of Cleavable Acrylate-Vinyl Ether Divinyl Monomer via Nitroxide-Mediated Radical Polymerization: Copolymer beyond Reactivity Ratio.

Cyclopolymerization of a divinyl monomer, where two different vinyl groups, that is, acrylate and vinyl ether, are connected via an ester bond, was performed under diluted condition with nitroxide-meditated radical polymerization (NMP). Both vinyl groups were consumed at almost same rate under suitable condition, although the inherent cross-propagation ability between the two vinyl groups are pretty low in radical copolymerization. Furthermore, the polymerization was controlled to some extent to give polymers of unimodal molecular weight distributions. The results obviously differed from copolymerization and homopolymerization with vinyl monomers that constitutes the divinyl monomer, 2-methoxyethyl acrylate and 2-acetoxyethyl vinyl ether. Structural analyses indicated formation of the cyclopolymer but the cyclo-efficiency was imperfect indicating that some units of olefinic dangling were incorporated. Eventually, the ester bonds of the cyclo units were cleaved to convert into the copolymer consisting of acrylic acid and 2-hydroxy ethyl vinyl ether and the composition ratio (DPacryl/DPVE) was 55:45. The copolymer showed higher glass transition temperature than that estimated from the composition ratio and Tg values of the homopolymers, which is likely due to the formation of quasi-cyclopolymer between carboxylic acid and hydroxy groups aligned in alternating fashion.

Alternating Sequence Control for Carboxylic Acid and Hydroxy Pendant Groups by Controlled Radical Cyclopolymerization of a Divinyl Monomer Carrying a Cleavable Spacer.

By utilizing features of the hemiacetal ester (HAE) bond: easy formation from vinyl ether and carboxylic acid and easy cleavage into different functional groups (-COOH and -OH), we achieved control of the alternating sequence of two functional pendant groups of a vinyl copolymer. Methacrylate- and acrylate-based vinyl groups were connected through HAE bonds to prepare a cleavable divinyl monomer, which was cyclo-polymerized under optimized conditions in a ruthenium-catalyzed living radical polymerization. Subsequent cleavage of the HAE bonds in the resultant cyclo-pendant led to a copolymer consisting of alternating methacrylic acid and 2-hydroxyethyl acrylate units as analyzed by 13 C NMR spectroscopy. The alternating sequence of -COOH and -OH pendants specifically provided a lower critical solution temperature (LCST) in an ether solvent, which was not observed with the random copolymer of same composition ratio.