Devitrification and recrystallization of nanoparticle-containing glycerol and PEG-600 solutions

De novo design of a nanoregulator for the dynamic restoration of ovarian tissue in cryopreservation and transplantation

The cryopreservation and transplantation of ovarian tissue underscore its paramount importance in safeguarding reproductive capacity and ameliorating reproductive disorders. However, challenges persist in ovarian tissue cryopreservation and transplantation (OTC-T), including the risk of tissue damage and dysfunction. Consequently, there has been a compelling exploration into the realm of nanoregulators to refine and enhance these procedures. This review embarks on a meticulous examination of the intricate anatomical structure of the ovary and its microenvironment, thereby establishing a robust groundwork for the development of nanomodulators. It systematically categorizes nanoregulators and delves deeply into their functions and mechanisms, meticulously tailored for optimizing ovarian tissue cryopreservation and transplantation. Furthermore, the review imparts valuable insights into the practical applications and obstacles encountered in clinical settings associated with OTC-T. Moreover, the review advocates for the utilization of microbially derived nanomodulators as a potent therapeutic intervention in ovarian tissue cryopreservation. The progression of these approaches holds the promise of seamlessly integrating nanoregulators into OTC-T practices, thereby heralding a new era of expansive applications and auspicious prospects in this pivotal domain.

Starch nanoparticles as a new ice crystal nucleator in Lactobacillus bulgaricus CICC 6097 cryoprotection

This work aimed at studying the cryoprotective effect of starch nanoparticles (SNPs) as ice nucleators on Lactobacillus bulgaricus CICC 6097 and exploring the protective mechanism. SNPs with a diameter of 363 nm were obtained, which possessed special properties to enhance ice nucleation and blunt ice crystals edges, and can be wrapped around the surface of bacteria form a protective barrier, thus maintaining the integrity of cell membranes and improving the survivability of L. bulgaricus CICC 6097 from 36.09% to 75.56%. However, SNCs solution formed ice crystals with obvious spikes during freezing, which was harmful to bacteria survival. Therefore, SNPs addition is a possible strategy for increasing viable cell counts during freezing. To the best of our knowledge, this report is the first to demonstrate the cryoprotective effect of ice nucleator on lactic acid bacteria.

Ovarian tissue cryopreservation and transplantation for fertility preservation

Background: As the number of cancer survivors has increased with advancements in cancer treatment, fertility preservation has become a treatment goal. Ovarian tissue cryopreservation (OTC) and transplantation (OTT) has made great progress over the past few decades. It has become the treatment of choice for fertility preservation in adolescents or patients in urgent need of chemotherapy. However, it is considered to be experimental compared with oocyte or embryo cryopreservation in some countries. Nevertheless, OTC and OTT is regarded as the more ideal method for fertility preservation in that it can also restore hormonal functions.Current Concepts: Currently, over 200 live births have been reported worldwide after OTC and OTT, proving the excellence of the technology. However, before its application in clinical settings, some challenges, including cryoinjury, ischemic injury, and cancer cell reimplantation, should be overcome. For cryoinjury, studies are underway on protocol improvement with the addition of agents such as antifreeze protein during cryopreservation. For ischemic injury, various agents have been studied to promote angiogenesis or revascularization. Furthermore, studies are underway on artificial ovary or xenotransplantation for fertility preservation in an effort to avoid cancer cell metastasis.Discussion and Conclusion: OTC and OTT is a clinically applicable option for fertility preservation. To set OTC and OTT as an established method for fertility preservation, further research is necessary to overcome the current challenges.

Cryoprotectant-dependent control of intracellular ice recrystallization in hepatocytes using small molecule carbohydrate derivatives

To promote the recovery of cells that undergo intracellular ice formation (IIF), it is imperative that the recrystallization of intracellular ice is minimized. Hepatocytes are more prone to IIF than most mammalian cells, and thus we assessed the ability of novel small molecule carbohydrate-based ice recrystallization inhibitors (IRIs) to permeate and function within hepatocytes. HepG2 monolayers were treated with N-(4-chlorophenyl)-d-gluconamide (IRI 1), N-(2-fluorophenyl)-d-gluconamide (IRI 2), or para-methoxyphenyl-β-D-glycoside (IRI 3) and fluorescent cryomicroscopy was used for real time visualization of intracellular ice recrystallization. Both IRI 2 and IRI 3 reduced rates of intracellular recrystallization, whereas IRI 1 did not. IRI 2 and IRI 3, however, demonstrated a marked reduction in efficiency in the presence of the most frequently used permeating cryoprotectants (CPAs): glycerol, propylene glycol (PG), dimethyl sulfoxide (DMSO), and ethylene glycol (EG). Nevertheless, IRI 3 reduced rates of intracellular recrystallization relative to CPA-only controls in the presence of glycerol, PG, and DMSO. Interestingly, IRI preparation in trehalose, a commonly used non-permeating CPA, did not impact the activity of IRI 3. However, trehalose did increase the activity of IRI 1 while decreasing that of IRI 2. While this study suggests that each of these compounds could prove relevant in hepatocyte cryopreservation protocols where IIF would be prominent, CPA-mediated modulation of intracellular IRI activity is apparent and warrants further investigation.

Cryopreservation of Human Ovarian Tissue: A Review

BACKGROUND

Cryopreservation of human ovarian tissue has been increasingly applied worldwide to safeguard fertility in cancer patients, notably in young girls and women who cannot delay the onset of their treatment. Moreover, it has been proposed to patients with benign pathologies with a risk of premature ovarian insufficiency. So far, more than 130 live births have been reported after transplantation of cryopreserved ovarian tissue, and almost all patients recovered their ovarian function after tissue reimplantation.

SUMMARY

This review aims to summarize the recent results described in the literature regarding human ovarian tissue cryopreservation in terms of methods and main results obtained so far. To cryopreserve human ovarian tissue, most studies describe a slow freezing/rapid thawing protocol, which is usually an adaptation of a protocol developed for sheep ovarian tissue. Since freezing has been shown to have a deleterious effect on ovarian stroma and granulosa cells, various research groups have been vitrifying ovarian tissue. Despite promising results, only 2 babies have been born after transplantation of vitrified/warmed ovarian tissue. Optimization of both cryopreservation strategies as well as thawing/warming protocols is therefore necessary to improve the survival of follicles in cryopreserved ovarian tissue.

KEY MESSAGES

Human ovarian tissue cryopreservation has been successfully applied worldwide to preserve fertility in patients with malignant or nonmalignant pathologies that have a detrimental effect on fertility. Human ovarian tissue cryopreservation could also be applied as an alternative to postpone pregnancy or menopause in healthy women. Slow freezing and vitrification procedures have been applied to cryopreserve human ovarian tissue, but both alternatives require optimization.

Analysis of polarized-light effects in glass-promoting solutions with applications to cryopreservation and organ banking

This study presents experimental results and an analysis approach for polarized light effects associated with thermomechanical stress during cooling of glass promoting solutions, with applications to cryopreservation and tissue banking in a process known as vitrification. Polarized light means have been previously integrated into the cryomacroscope-a visualization device to detect physical effects associated with cryopreservation success, such as crystallization, fracture formation, and contamination. The experimental study concerns vitrification in a cuvette, which is a rectangular container. Polarized light modeling in the cuvette is based on subdividing the tridimensional (3D) domain into a series of planar (2D) problems, for which a mathematical solution is available in the literature. The current analysis is based on tracking the accumulated changes in light polarization and magnitude, as it passes through the sequence of planar problems. Results of this study show qualitative agreement in light intensity history and distribution between experimental data and simulated results. The simulated results help explaining differences between 2D and 3D effects in photoelasticity, most notably, the counterintuitive observation that high stress areas may correlate with low light intensity regions based on the particular experimental conditions. Finally, it is suggested that polarized-light analysis must always be accompanied by thermomechanical stress modeling in order to explain 3D effects.

Topical delivery of TRPsiRNA-loaded solid lipid nanoparticles confer reduced pain sensation via TRPV1 silencing, in rats

Present work describes a novel composition for encapsulating TRPsiRNA (TRPV1-targeting siRNA) within lipid-matrix (4:1::glyceryl behnate:stearic acid) of SLNs, using suitably modified cold high-pressure homogenisation technique. Optimisation of the method and composition conducted using calf-thymus DNA (ctDNA), to avoid cost of TRPsiRNA molecules, resulted in small size (d₅₀ = 50-100 nm) and high entrapment (77.22-98.5%). Complete masking of extreme negative charge of both ctDNA (-34.50 mV) and TRPsiRNA (-23.98 mV) upon encapsulation in SLNs without employing cationic components is reported herein for the first time. Diffusion-controlled release (90.17% at 72 h) from a rigid matrix shifted to porous matrix (at 24 h) due to solubilisation of stearic acid at 37 °C. Efficient in vitro (HEK293 T cells) and in vivo transfection and expression established the proof-of-concept. PEG600 as supporting-surfactant and vitrifying agent promoted small size, effective transfection and rupture of endosomal membrane to affect endosomal escape. Physiological efficacy in terms of significant increase (p < .0001) in paw-withdrawal-latency, following topical and intradermal application of TRPsiRNA-loaded SLNs, in rats, exposed to thermal hyperalgesia (145 and 182%, respectively) and capsaicin-induced pain (155 and 182%, respectively) indicate effective silencing of skin TRPV1. Significant decrease in intensity and duration (one-fifth) of capsaicin-induced nocifensive behaviour was also observed. Naked TRPsiRNA, however, did not show any effect.

Magnetic induction heating of superparamagnetic nanoparticles during rewarming augments the recovery of hUCM-MSCs cryopreserved by vitrification

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.

Effect of iron oxide nanoparticles on the permeability properties of Sf21 cells

It was recently reported that nanoparticles could significantly modulate the thermal properties of solutions at subzero temperatures, and as a result, nanoparticles have been widely used in both cryopreservation and cryosurgery. In cryopreservation, the water permeability coefficient of cell membrane is an essential parameter for quantitative investigation of cell dehydration and intracellular ice formation. However, few studies were focused on the effects of nanoparticles on the permeability properties of cell membrane. In order to optimize the processes of cryopreservation with nanoparticles, we measured the permeability properties of Sf21 cells in the presence of iron oxide nanoparticles in this study. The responses of Sf21 cells with iron oxide nanoparticles were obtained by the microperfusion system at -2, 5, 15 and 25 °C, respectively. The osmotically inactive cell volume (Vb), the cell membrane hydraulic conductivity (Lp) and it's activation energy (ELp), and the reference value of Lp at the reference temperature (Lpg) with 0.02%, 0.1% and 0.5% (w/w) iron oxide nanoparticles were determined by 2-parameter (2-p) model at -2, 5, 15 and 25 °C. We analyzed the effects of iron oxide nanoparticles on the permeability properties of the Sf21 cells. The results indicated that iron oxide nanoparticles have a significant influence on membrane permeability properties (Lpg and ELp) of Sf21 cells. The introduction of iron oxide nanoparticles tends to increase the values of Vb and Lpg, while decrease the value of ELp. These findings may provide a new route to optimize the biomaterial cryopreservation.

Effect of Hydroxyapatite Nanoparticles on Biotransport Phenomena in Freezing HeLa Cells

The effect of nanoparticles on subzero biotransport phenomena of living cells is very rare in the literature, although the information is of great importance for the application of nanotechnology in the field of cryobiology. In this study, subzero water transport phenomena in freezing HeLa cells in 1 × phosphate buffered saline (PBS) containing 0%, 0.05%, and 0.1% (w/w) hydroxyapatite (HA) nanoparticles with and without pre-incubation at 37 °C was quantitatively investigated. The results reveal that the presence of HA nanoparticles slightly facilitates the subzero water transport of HeLa cells.

Influence of hydroxyapatite nanoparticles on the viscosity of dimethyl sulfoxide-H2O-NaCl and glycerol-H2O-NaCl ternary systems at subzero temperatures

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.

Effect of hydroxyapatite nanoparticles on osmotic responses of pig iliac endothelial cells

In order to fully explore the potential applications of nanoparticles in biopreservation, it is necessary to study the effect of nanoparticles on cell membrane permeabilities. The aim of this study is therefore to comparatively evaluate the osmotic responses of pig iliac endothelial cells in the absence and presence of commercially available hydroxyapatite nanoparticles. The results indicate that, after the introduction of 0.0 1 wt% hydroxyapatite nanoparticles, the dependence of cell membrane hydraulic conductivity (Lp) on temperature still obeys the Arrhenius relationship, while the reference value of the hydraulic conductivity of the cell membrane at 273.15K (Lpg) and the activation energy for water transport across cell membrane (ELp) change from 0.77 × 10(-14)m/Pa/s and 15.65 kJ/mol to 0.65 × 10(-14)m/Pa/s and 26.14 kJ/mol. That is to say, the reference value of the hydraulic conductivity of the cell membrane has been slightly decreased while the activation energy for water transport across cell membrane has been greatly enhanced, and thus it implies that the hydraulic conductivity of cell membrane are more sensitive to temperature in the presence of nanoparticles. These findings are of potential significance to the optimization of nanoparticles-aided cryopreservation.