Mohammed Saleem, Ali2025-08-052025-08-052025-08-05http://hdl.handle.net/10393/50730https://doi.org/10.20381/ruor-31298Over the years, methods to preserve biological samples, such as red blood cells, have been explored and researched. Currently, cryopreservation of biological samples is the most commonly used method for long-term storage of cells and tissues. Cryopreservation stores samples at very low temperatures, typically ranging between -80 °C to -196 °C - temperatures at which biochemical processes are effectively halted. However, at this temperature, cellular damage due to cryoinjury is a major concern. The causes of cryoinjury are mainly due to two major factors, osmotic pressure and mechanical damage due to ice formation. Both issues can be mitigated with the use of cryoprotectants, chemical additives that are added to a sample prior to preserving it at -80 °C to -196 °C. Moreover, some cryoprotectants exhibit properties of ice recrystallization inhibitors (IRIs), which reduce the growth rate of ice crystals and lead to a decrease in cellular damage due to the aforementioned factors. In this thesis, the IRI activity of Wang and PEGA resins was evaluated, finding no IRI activity when compared with 2FA, a well-known IRI. As Wang and PEGA resins are commonly coupled with amino acids during solid phase synthesis, the IRI activity of the resins functionalized with different amino acids was also tested. To determine which amino acid to couple with the resin, the IRI activity of various amino acids was tested, along with some of their β-amino acid counterparts. Among the amino acids tested, L-phenylalanine exhibited the highest IRI active, with an IC₅₀ = 14.0 mM [12.3, 15.6], while L-glycine showed the lowest IRI active, with an IC₅₀ = 287.1 mM [242.3, 316.2]. Moreover, all the tested β-amino acids had less IRI activity compared to their α-amino acid isomer. Using this information, the IRI activity of functionalized Wang and PEGA resin - Wang-Gly, Wang-Gly-Phe, Wang-Gly-Lys, PEGA-Phe, and PEGA-Lys - was evaluated, finding no IRI activity when compared with 2FA. In order to enhance the IRI activity of amino acids, the most IRI active amino acid tested, L-phenylalanine, was used as the starting material to synthesize and evaluate the IRI activity of acylated and alkylated amino acid derivatives. N-acyl-L-phenylalanine showed either low solubility, a decrease in IRI activity, or both when compared with L-phenylalanine. On the other hand, N-isopropyl-phenylalanine showed enhanced IRI activity, with an IC₅₀ = 1.3 mM [0.9, 1.7] compared to L-phenylalanine’s IC₅₀ = 14.0 mM [12.3, 15.6]. As the IRI activity of some amino acids was tested, L-phenylalanine showed the best IRI activity compared with the other tested amino acids. However, the IRI active amino acids showed no discernable IRI activity when conjugated to insoluble organic resins, Wang and PEGA. Derivatives of L-phenylalanine, such as N-isopropyl-phenylalanine, showed high IRI activity with an IC₅₀ = 1.3 mM [0.9, 1.7], which could potentially be conjugated to the insoluble organic beads such as Wang and PEGA resins to test whether that would cause the resins to exhibit IRI activity.enIce recrystallization inhibitorCryopreservationThesis