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Wang J.,University of Electronic Science and Technology of China | Zhao G.,University of Electronic Science and Technology of China | Zhao G.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs | Zhang Z.,Anhui Huien Biotechnology Corporation | And 2 more authors.
Acta Biomaterialia | Year: 2016

Cryopreservation by vitrification has been recognized as a promising strategy for long-term banking of living cells. However, the difficulty to generate a fast enough heating rate to minimize devitrification and recrystallization-induced intracellular ice formation during rewarming is one of the major obstacles to successful vitrification. We propose to overcome this hurdle by utilizing magnetic induction heating (MIH) of magnetic nanoparticles to enhance rewarming. In this study, superparamagnetic (SPM) Fe3O4 nanoparticles were synthesized by a chemical coprecipitation method. We successfully applied the MIH of Fe3O4 nanoparticles for rewarming human umbilical cord matrix mesenchymal stem cells (hUCM-MSCs) cryopreserved by vitrification. Our results show that extracellular Fe3O4 nanoparticles with MIH may efficiently suppress devitrification and/or recrystallization during rewarming and significantly improve the survival of vitrified cells. We further optimized the concentration of Fe3O4 nanoparticles and the current of an alternating current (AC) magnetic field for generating the MIH to maximize cell viability. Our results indicate that MIH in an AC magnetic field with 0.05% (w/v) Fe3O4 nanoparticles significantly facilitates rewarming and improves the cryopreservation outcome of hUCM-MSCs by vitrification. The application of MIH of SPM nanoparticles to achieve rapid and spatially homogeneous heating is a promising strategy for enhanced cryopreservation of stem cells by vitrification. Statement of Significance: Here we report the successful synthesis and application of Fe3O4 nanoparticles for magnetic induction heating (MIH) to enhance rewarming of vitrification-cryopreserved human umbilical cord matrix mesenchymal stem cells (hUCM-MSCs). We found that MIH-enhanced rewarming greatly improves the survival of vitrification-cryopreserved hUCM-MSCs. Moreover, the hUCM-MSCs retain their intact stemness and multilineage potential of differentiation post cryopreservation by vitrification with the MIH-enhanced rewarming. Therefore, the novel MIH-enhanced cell vitrification is valuable to facilitate the long-term storage of hUCM-MSCs and possibly many other important cells to meet their ever-increasing demand by the burgeoning cell-based medicine. © 2016 Acta Materialia Inc. Source


Yi J.,University of Electronic Science and Technology of China | Tang H.,University of Electronic Science and Technology of China | Zhao G.,University of Electronic Science and Technology of China | Zhao G.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs
Cryobiology | Year: 2014

The viscosity, at subzero temperatures, of ternary solutions commonly used in cryopreservation is tremendously important for understanding ice formation and molecular diffusion in biopreservation. However, this information is scarce in the literature. In addition, to the best of our knowledge, the effect of nanoparticles on the viscosity of these solutions has not previously been reported. The objectives of this study were thus: (i) to systematically measure the subzero viscosity of two such systems, dimethyl sulfoxide (Me2SO)-H2O-NaCl and glycerol-H2O-NaCl; (ii) to explore the effect of hydroxyapatite (HA) nanoparticles on the viscosity; and (iii) to provide models that precisely predict viscosity at multiple concentrations of cryoprotective agent (CPA) in saline solutions at subzero temperatures. Our experiments were performed in two parts. We first measured the viscosity at multiple CPA concentrations [0.3-0.75 (w/w)] in saline solution with and without nanoparticles at subzero temperatures (0 to -30 °C). The data exhibited a good fit to the Williams-Landel-Ferry (WLF) equation. We then measured the viscosity of residual unfrozen ternary solutions with and without nanoparticles during equilibrium freezing. HA nanoparticles made the solution more viscous, suggesting applications for these nanoparticles in preventing cell dehydration, ice nucleation, and ice growth during freezing and thawing in cryopreservation. © 2014 Elsevier Inc. All rights reserved. Source


Wang Z.,University of Electronic Science and Technology of China | Zhao G.,University of Electronic Science and Technology of China | Zhao G.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs | Wang T.,University of Electronic Science and Technology of China | And 3 more authors.
Applied Thermal Engineering | Year: 2015

A three-dimensional cell-to-tissue multiscale model for quantitative evaluation of the influences of vascular network on the treatment outcome of combined cancer therapy of cryosurgery and hyperthermia was developed, where the bioheat transfer equation was used to predict the thermal history in both the tumor and normal tissues, the Navier-Stokes equations were used to calculate the temperature and flow fields in the vascular network generated using fractal theory based on MRI images, and the thermal and cryo damage functions together with the injury caused by intracellular ice formation were used for evaluating the killing effect. The effects of the vascular tree on both the thermal history and intracellular ice formation in the tissues were investigated. For a tumor located at the first level of vascular network, the vascular network is significant only when the distance between the tumor and blood vessel is less than three times of the radius (R) of the tumor and this critical distance decreases to 2R for the second level of the vascular tree. For a fixed distance between tumor and blood vessel, the first level of vascular network was found to be thermally significant while the third or lower levels of vascular tree are not. © 2015 Elsevier Ltd. Source


Wang T.,University of Electronic Science and Technology of China | Wang T.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs | Zhao G.,University of Electronic Science and Technology of China | Zhao G.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs | And 6 more authors.
Applied Thermal Engineering | Year: 2015

Abstract The most challenging issue in cryopreservation of mass biomaterials is to rewarm the frozen sample in a fast and uniform manner, so that the dangerous devitrification and recrystallization may be avoided. In this study, a conceptual innovation is the design of a novel cryovial, and we investigate the effects of the microwave heating after embedding superparamagnetic nanoparticles on the rewarming processes of the cell suspensions encapsulated in the cryovial. The electromagnetic field and the heat transfer during the hybrid rewarming processes of frozen EC2 solution with temperature-dependent properties were calculated. During the rewarming process of the sample in the cryovial in a traditional 37 C water bath, the rewarming rate was 72.15 C/min and the maximum temperature gradient in the sample was 20.5 C/mm. After a slot antenna was included in the cryovial, the rewarming rate was 83.71 C/min without nanoparticles and 106.41 C/min after nanoparticles are embedded, the maximum temperature gradient in the sample was 40.2 C/mm without nanoparticles and 28.7 C/mm after nanoparticles embedded, respectively. This indicates that the rewarming rate and the uniformity of the temperature distribution increased after embedding nanoparticles. This could be because nanoparticles homogeneously generate heat in the sample and improve the time-dependent parameters of the sample. © 2015 Elsevier Ltd. Source


Tian T.,Anhui Medical University | Zhao G.,Anhui Provincial Engineering Technology Research Center for Biopreservation and Artificial Organs | Zhao G.,University of Electronic Science and Technology of China | Han D.,Anhui Medical University | And 11 more authors.
Human Reproduction | Year: 2015

Study Question Is sucrose more effective than trehalose in human ovarian tissue cryopreservation? Summary Answer The effect of sucrose as a cryoprotective agent (CPA) was not significantly different from that of trehalose in human ovarian tissue cryopreservation. What is Known Already Sugars have the ability to keep the cell membrane intact and can decrease the toxicity of CPAs. Sucrose is the most commonly used non-permeable CPA, while trehalose is rarely used in human ovarian tissue cryopreservation. Although various methods are utilized to evaluate the efficiency of human ovarian tissue cryopreservation, few studies have evaluated the effect of cryopreservation from the viewpoint of biomechanics. Study Design, Size, Duration A total of 15 ovarian tissue samples were collected from 15 patients (20-41 years old) with benign ovarian tumors or malignancies, and each was dissected into six slices. Two slices were taken as the fresh control group. The remaining four slices were vitrified using different vitrification protocols. After warming, samples in each group were either fixed for histological evaluation or destined for stress relaxation test. Participants/Materials, Setting, Methods The CPA solutions for the control and vitrified groups were composed of EDS and EDT (E, ethylene glycol; D, dimethylsulphoxide; S, sucrose; T, trehalose). The stress relaxation experiments were carried out at room temperature using a dynamic mechanical analyzer. Ovarian tissue samples were assessed for both their morphology and viscoelasticity. Stress relaxation data (SRD) were calculated as a percentage, representing the ability to maintain the initial stress after stretching. The percentage of morphologically normal follicles was compared between groups, which was represented by morphologic preservation ratio. Main Results and The Role of Chance The morphologic preservation ratio of the primordial follicles in the fresh control group (87.58%) was higher than that in group S (72.33%) (P = 0.000) and group T (79.56%) (P = 0.002). Although not statistically significant, compared with the S group, vitrification with T suggested a trend toward a higher morphologic preservation ratio of the primordial follicles. The SRD in the fresh control group (0.6433 ± 0.7233) was significantly different from that in group S (0.5200 ± 0.8331, P = 0.000) or in group T (0.5667 ± 0.6415, P = 0.000). However, no significant difference was found between groups S and T. Limitations, Reasons For Caution Experimental samples were directly exposed to the air, which will result in a discrepancy in the viscoelastic properties between experimental tissues and in vivo tissues. Wider Implications of The Findings Our study suggested a trend toward a higher morphologic preservation ratio of the primordial follicles after vitrification in trehalose compared with sucrose, which may provide a basis for further optimizing human ovarian tissue vitrification. In addition, it was possible to evaluate the effect of ovarian tissue cryopreservation from a biomechanics perspective. Study Funding/Competing Interest(S) This study was supported by the grants from the Medical Scientific Research Subject, Health Ministry of Anhui Province (2010B014) and National Basic Research Program of China (973 Program) (2012CB944704), and the National Natural Science Foundation of China (Nos. 51276179 and 51476160). The authors declare that there is no conflict of interests regarding the publication of this original paper. © 2015 The Author. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. Source

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