Mechanical Engineering MS Thesis Defense by Mr. Alexander N. Sinkevich
When: Friday,
July 24, 2015
11:00 AM
-
1:00 PM
Where: Textiles Building 101E
Description: Mechanical Engineering MS THESIS DEFENSE by
Mr. Alexander N. Sinkevich
DATE:
July 24, 2015
TIME:
11:00 a.m. – 1:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Strategies for Overcoming Transport Limitations of Convective Desiccation of Trehalose Solutions for Ambient Temperature Preservation of Biologics
ABSTRACT:
Lyopreservation is the preservation of complex biologics inside water-disaccharide solutions (trehalose being the disaccharide) by convectively drying the solutions at ambient temperatures. As an aqueous trehalose solution dries to a water content below 10 wt.%, a glassy skin forms at the solution-vapor interface and preserves the stored biologic. Recovery of viable biologics in the literature has been limited, leading to a repeated conjecture that water transport limitations prevent uniform glass formation at the cellular level. In addition, solute transport during the desiccation process may also prevent uniform glass formation at the solution surface. This thesis work utilizes commercial finite element software COMSOL Multiphysics to investigate ways to allow rapid formation of a uniform glassy layer around a mammalian cell. It first explores in a one-dimensional thin film model various boundary conditions to see if glass formation at the cellular level can be accelerated for both natural and forced convective cases. A sessile droplet model is also developed to investigate how different droplet profiles influence solute transport. Results show that using higher substrate or environmental temperatures helps remove water but is too dangerous for cellular survival and also lowers the water content necessary to form glass. Heating the substrate in a controlled, sinusoidal manner circumvents this issue by always periodically returning to room temperature. Increasing the wave frequency helps rapidly form glass at the cellular layer. However, obtaining a water content necessary for complete glass formation within the cell requires either increased amounts of intracellular trehalose or post-desiccation storage temperatures lower than room temperature. Using sinusoidal heating on substrates with hydrophobic surfaces strengthens Marangoni flow and results in enhanced heat transfer within the solution and cooler temperatures at the cellular layer. The solute transport while using hydrophobic surfaces results in a top-down glass formation pattern, which may be more beneficial for encapsulating biologics.
CO-ADVISOR:
Dr. Sankha Bhowmick
(sbhowmick@umassd.edu, 508-999-8619)
CO-ADVISOR:
Dr. Mehdi Raessi
(mraessi@umassd.edu, 508-999-8496)
COMMITTEE MEMBER:
Dr. Amit Tandon
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Sankha Bhowmick or Dr. Mehdi Raessi at the E-mail and/or telephone number above.
Thank you,
Sue Cunha, Administrative Assistant
scunha@umassd.edu
508-999-8492
Mr. Alexander N. Sinkevich
DATE:
July 24, 2015
TIME:
11:00 a.m. – 1:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Strategies for Overcoming Transport Limitations of Convective Desiccation of Trehalose Solutions for Ambient Temperature Preservation of Biologics
ABSTRACT:
Lyopreservation is the preservation of complex biologics inside water-disaccharide solutions (trehalose being the disaccharide) by convectively drying the solutions at ambient temperatures. As an aqueous trehalose solution dries to a water content below 10 wt.%, a glassy skin forms at the solution-vapor interface and preserves the stored biologic. Recovery of viable biologics in the literature has been limited, leading to a repeated conjecture that water transport limitations prevent uniform glass formation at the cellular level. In addition, solute transport during the desiccation process may also prevent uniform glass formation at the solution surface. This thesis work utilizes commercial finite element software COMSOL Multiphysics to investigate ways to allow rapid formation of a uniform glassy layer around a mammalian cell. It first explores in a one-dimensional thin film model various boundary conditions to see if glass formation at the cellular level can be accelerated for both natural and forced convective cases. A sessile droplet model is also developed to investigate how different droplet profiles influence solute transport. Results show that using higher substrate or environmental temperatures helps remove water but is too dangerous for cellular survival and also lowers the water content necessary to form glass. Heating the substrate in a controlled, sinusoidal manner circumvents this issue by always periodically returning to room temperature. Increasing the wave frequency helps rapidly form glass at the cellular layer. However, obtaining a water content necessary for complete glass formation within the cell requires either increased amounts of intracellular trehalose or post-desiccation storage temperatures lower than room temperature. Using sinusoidal heating on substrates with hydrophobic surfaces strengthens Marangoni flow and results in enhanced heat transfer within the solution and cooler temperatures at the cellular layer. The solute transport while using hydrophobic surfaces results in a top-down glass formation pattern, which may be more beneficial for encapsulating biologics.
CO-ADVISOR:
Dr. Sankha Bhowmick
(sbhowmick@umassd.edu, 508-999-8619)
CO-ADVISOR:
Dr. Mehdi Raessi
(mraessi@umassd.edu, 508-999-8496)
COMMITTEE MEMBER:
Dr. Amit Tandon
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Sankha Bhowmick or Dr. Mehdi Raessi at the E-mail and/or telephone number above.
Thank you,
Sue Cunha, Administrative Assistant
scunha@umassd.edu
508-999-8492
Topical Areas: University Community, College of Engineering, Mechanical Engineering