Effective Cryopreservation and Recovery of Living Cells Encapsulated in Multiple Emulsions.

Background: The ability to preserve living cells or stem cells is critical for their use in cell therapy, especially for regenerative, reproductive, and transfusion medicine. This article addresses the low survival rates of cells and their loss of function during traditional freezing and banking (cells in a liquid medium with cryoprotectants). Aim: In this article, we developed multiple emulsions (water-in-oil-in-water type) for the effective encapsulation and cryopreservation of cells. In multiple emulsions, the oil drops, acting as a protective membrane, contain even smaller water droplets with encapsulated living cells, dispersed in the continuous water phase. Materials and Methods: The multiple emulsions with HEK293 cells encapsulated in the internal alginate droplets were successfully prepared in a Couette-Taylor flow biocontactor. The cryoprotectants (sucrose/dimethyl sulfoxide-DMSO) were located within the internal or external or both water phases of the emulsions. Encapsulated and non-encapsulated cells were frozen to -80°C (cooling rate: -1°C/min) and then transferred to liquid nitrogen (-196°C) for 24 hours. The standard rapid warming procedure was applied to thaw samples. Cell proliferation and viability were measured by using the AlamarBlue™ assay after recovery of cells. Results: The results showed that the viability of cells encapsulated in the internal droplets of multiple emulsions, and then cryopreserved, was significantly higher, up to 27.9%, than that observed for cells conventionally cryopreserved (non-encapsulated cells in water). Moreover, the effective cell-loaded multiple emulsions-based banking method allowed DMSO-toxic cryoprotectant-to be eliminated from the cryopreservation system. Conclusion: The proposed approach of the cryoprotection of cells encapsulated in multiple emulsions could minimize cell damage, degradation, and their loss during freezing-thawing processes.

Multiple emulsions as effective platforms for controlled anti-cancer drug delivery.

AIM: Developing pH-responsive multiple emulsion platforms for effective glioblastoma multiforme therapy with reduced toxicity, a drug release study and modeling. MATERIALS & METHODS: Cancer cell line: U87 MG, multiple emulsions with pH-responsive biopolymer and encapsulated doxorubicin (DOX); preparation of multiple emulsions in a Couette-Taylor flow biocontactor, in vitro release study of DOX (fluorescence intensity analysis), in vitro cytotoxicity study (alamarBlue cell viability assay) and numerical simulation of DOX release rates. RESULTS: The multiple emulsions offered a high DOX encapsulation efficiency (97.4 ± 1%) and pH modulated release rates of a drug. Multiple emulsions with a low concentration of DOX (0.02 µM) exhibited broadly advanced cell (U87 MG) cytotoxicity than free DOX solution used at the same concentration. CONCLUSION: Emulsion platforms could be explored for potential delivery of chemotherapeutics in glioblastoma multiforme therapy.

Cryoprotection and banking of living cells in a 3D multiple emulsion-based carrier.

The ability to preserve stem cells/cells with minimal damage for short and long periods of time is essential for advancements in biomedical therapies and biotechnology. New methods of cell banking are continuously needed to provide effective damage prevention to cells. This paper puts forward a solution to the problem of the low viability of cells during cryopreservation in a traditional suspension and storage by developing innovative multiple emulsion-based carriers for the encapsulation and cryopreservation of cells. During freezing-thawing processes, irreversible damage to cells occurs as a result of the formation of ice crystals, cell dehydration, and the toxicity of cryoprotectant. The proposed method was effective due to the "flexible" protective structure of multiple emulsions, which was proven by a high cell survival rate, above 90%. Results make new contributions in the fields of cell engineering and biotechnology and contribute to the development of methods for banking biological material.