Synthesis of dendrimer antifreezes and applications in cryopreservations
Standing
Undergraduate
Type of Proposal
Oral Presentation
Faculty
Faculty of Science
Proposal
Nature uses carbohydrates for many different important roles in biological systems. Certain organisms, including Antarctic teleost fish, have evolved carbohydrate-containing biomolecules that act as antifreezes, antifreeze glycoproteins (AFGPs), helping the fish survive their sub-zero environments. The biological antifreezes act through two different mechanisms: thermal hysteresis (TH) which is the selective depression of the freezing point without changing the melting point of water (this prevents the formation of ice crystals in the hysteretic gap); and ice recrystallization inhibition (IRI), where the compounds prevent the growth of large crystals at the expense of small crystals during the thawing process. Natural AFGPs show IRI activity, and this could be useful for the cryopreservation of organs and tissue; however, they also have potent TH activity that leads to damage during freezing. These two effects must be decoupled in any useful cryopreservative, otherwise organs will be damaged as they are frozen. We aim to make dendron-based cryopreservatives (Figures 1) which feature varying numbers of branch heads containing galactose, a sugar previously shown to exhibit very potent IRI effects due to its unique ability to disrupt water deposition onto a growing ice crystal. Dendrons are predicted to be very effective due to their multi-valency and their large hydrophobic body in combination with hydrophilic head portion, structural features thought to greatly aid IRI capabilities. Many different diseases and terminal conditions cannot be cured unless through organ replacement. The eventual goal of this project is to develop a means by which whole organs can be stored for longer durations of time allowing for increased chance of survival for people faced with debilitating health circumstances. In this presentation, the theory underlying biological antifreezes and their potential for applications in biomedicine, the synthesis of our materials, and the assays carried out to investigate the levels of IRI shown by our novel compounds will be shown.
Location
University of Windsor
Grand Challenges
Viable, Healthy and Safe Communities
Synthesis of dendrimer antifreezes and applications in cryopreservations
University of Windsor
Nature uses carbohydrates for many different important roles in biological systems. Certain organisms, including Antarctic teleost fish, have evolved carbohydrate-containing biomolecules that act as antifreezes, antifreeze glycoproteins (AFGPs), helping the fish survive their sub-zero environments. The biological antifreezes act through two different mechanisms: thermal hysteresis (TH) which is the selective depression of the freezing point without changing the melting point of water (this prevents the formation of ice crystals in the hysteretic gap); and ice recrystallization inhibition (IRI), where the compounds prevent the growth of large crystals at the expense of small crystals during the thawing process. Natural AFGPs show IRI activity, and this could be useful for the cryopreservation of organs and tissue; however, they also have potent TH activity that leads to damage during freezing. These two effects must be decoupled in any useful cryopreservative, otherwise organs will be damaged as they are frozen. We aim to make dendron-based cryopreservatives (Figures 1) which feature varying numbers of branch heads containing galactose, a sugar previously shown to exhibit very potent IRI effects due to its unique ability to disrupt water deposition onto a growing ice crystal. Dendrons are predicted to be very effective due to their multi-valency and their large hydrophobic body in combination with hydrophilic head portion, structural features thought to greatly aid IRI capabilities. Many different diseases and terminal conditions cannot be cured unless through organ replacement. The eventual goal of this project is to develop a means by which whole organs can be stored for longer durations of time allowing for increased chance of survival for people faced with debilitating health circumstances. In this presentation, the theory underlying biological antifreezes and their potential for applications in biomedicine, the synthesis of our materials, and the assays carried out to investigate the levels of IRI shown by our novel compounds will be shown.