Poly(l -Ala- co- l -Lys) Exhibits Excellent Ice Recrystallization Inhibition Activity

Zhengyu Piao, Jin Kyung Park, Madhumita Patel, Hyun Jung Lee, Byeongmoon Jeong

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The control of ice recrystallization is very important in cryo-technological fields such as the food industry, biopharmaceuticals, and cell storage. Ice recrystallization inhibition (IRI) compounds are therefore designed to limit the growth of ice crystals, decrease the crystal size, and control the crystal shape. To improve the IRI activity of cryo-systems, various synthetic polymers such as biomimetic polypeptides from polar fish, facially amphiphilic polymers, polyampholytes, poly(vinyl alcohol) derivatives, and block copolymers with hydrophilic-hydrophobic balance have been developed. Except for graphene oxide, poly(vinyl alcohol) has thus far exhibited the best performance among these polymers. Herein, poly(l-alanine-co-l-lysine) (PAK) was shown to exhibit a similar IRI activity to that of poly(vinyl alcohol). Moreover, in contrast to the needle-shaped ice crystals generated by the aqueous PVA solution, the PAK solution was shown to generate cubic-to-spherical shaped ice crystals. Furthermore, neither poly(l-alanine-co-l-aspartic acid) (PAD) nor poly(ethylene glycol) (PEG) with a similar molecular weight provided any significant IRI activity. Examination by FTIR and circular dichroism spectroscopies indicated that the PAK forms α-helices, whereas the PAD forms random coils in water. Further, a dynamic ice shaping study suggested that PAK strongly interacts with ice crystals, whereas PAD and PEG only weakly interact. These results suggest that PAK is an important compound with superior IRI activity and that this activity is dependent upon the functional groups and secondary structure of the polypeptides.

Original languageEnglish
Pages (from-to)1436-1442
Number of pages7
JournalACS Macro Letters
Volume10
Issue number11
DOIs
StatePublished - 16 Nov 2021

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (2020R1A2C2007101, 2017R1A5A1015365) and Korea Basic Science Institute (National Research Facilities and Equipment Center) Grant funded by the Ministry of Education (2020R1A6C 101B194).

Publisher Copyright:
© 2021 American Chemical Society.

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