Create biobased peptides and determine their mechanisms as ice recrystallization inhibitors

摘要：冰重结晶是大冰晶取代小冰晶的过程，是影响食品、生物医学组织和细胞培养物等生物材料在冷冻储存过程中质量和功能特性的关键问题。冰再结晶抑制作用是指冻结温度的波动对冰晶生长的抑制作用。虽然合成化学品可以用作冰生长抑制剂，但由于其毒性，其广泛应用受到限制。这项研究基于令人兴奋的初步发现，旨在了解从食物蛋白质水解（由于与水反应而分解）中获得的肽如何作为IRI剂，以及微小的结构修饰如何增强这种效果。本研究将探讨分子结构与IRI活性之间的关系，以便更好地了解其作用机制。这些生物基肽预计具有足够的IRI活性和低毒性。它们将在食品工业（提高冷冻食品的质量），农业（提高植物对冷冻温度的抵抗力），医学（细胞和组织的冷藏）和材料技术（除冰道路或飞机和气候控制）中有广泛的应用。从本研究中获得的知识和建立的评估工具将为未来的基础生物材料化学研究提供见解。该项目将为代表性不足的研究生和本科生提供STEM教育。通过解决当前的挑战和需求，培训将增加学生对基础化学在推动科学发展中的作用的理解。这将对学生运用基础知识解决问题的能力产生持久的影响。学生还将通过领导力培训、介绍FDA和EPA关于新型生物基化合物的法规、知识产权保护和技术采用，培养成为未来生物材料研究人员的关键技能。少数族裔学生的成功招募和培训将使系和学院的学生构成多样化，并为所有人创造一个包容和丰富的环境。技术摘要：冰在冷冻储存过程中的再结晶和生长是一个亟待解决的关键问题。为了避免合成防冻剂的毒性，迫切需要生物基和安全的化合物。基于研究小组令人兴奋的早期发现，该项目旨在研究通过生物催化水解和酰胺化反应从常见食物蛋白质中提取的肽对冰重结晶抑制（IRI）的作用。建立多肽的结构、理化性质与IRI活性之间的关系。对多肽的氢键能力及其两亲性如何影响IRI活性的基本理解将获得。利用一种新的振动和频率产生谱方法研究了多肽对冰-水界面行为的影响。因此，本研究解决了目前该领域未知的问题，即生物基肽的分子特征与IRI活性之间的关系。虽然IRI理论已经对一些纯化合物进行了测试，但对普通蛋白质的肽混合物知之甚少。蛋白质和多肽的结构多样性使得结构-功能研究具有挑战性，这需要在本工作中通过研究群体特征来解决。将氢键和两亲性作为IRI活性的关键因素是IRI研究的一个新角度，先进光谱学的应用将为研究IRI的作用机制提供新的见解。因此，本研究展示了使用创新的方法来识别生物相容性材料，以在冷冻条件下保持生物系统的质量和完整性。这项研究将为研究生和本科生研究助理提供变革性的经验，帮助他们了解如何利用化学原理解决问题。成功招募和培训具有不同背景的学生将为学院和当地社区的学术团体提供丰富的环境。学生对批判性思维、解决问题、团队合作和领导能力的基本技能的练习将导致未来生物材料研究人员的发展和一支能力强、适应性强的劳动力队伍。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract: Ice recrystallization, where large ice crystals replace small ones, is a critical problem that impacts quality and functional property of biomaterials, such as food, biomedical tissues, and cell cultures during freezing storage. Ice recrystallization inhibition (IRI) is the restriction of the growth of ice crystals caused by fluctuations in freezing temperature. Although synthetic chemicals can be used as ice growth inhibitors, their wide application is limited due to toxicity. This research, based on exciting preliminary findings, aims to understand how peptides obtained from hydrolysis (breakdown due to reaction with water) of food proteins can act as an IRI agent and how minor structural modification will enhance such effect. The research will address the relationship between molecular structure and IRI activity so that the mechanism of action can be better understood. These bio-based peptides are expected to have adequate IRI activity and low toxicity. They will have a wide range of applications in the food industry (increasing quality of frozen foods), agriculture (increasing resistance of plant to freezing temperatures), medicine (cold storage of cells and tissues), and material technology (deicing road or aircraft and climate control). The knowledge gained and evaluation tools established from this study will provide insights to future fundamental biomaterial chemistry research. This project will provide STEM education to underrepresented graduate and undergraduate students. The training will increase students’ understanding of the role of fundamental chemistry in advancing science through addressing the current challenges and needs. It will have a long-lasting impact on the students’ appreciation of applying basic knowledge in problem-solving. The students will also grow in key skills to become future biomaterial researchers through leadership training, and introduction to FDA and EPA regulations of new bio-based compounds and intellectual property protection and technology adoption. Successful recruitment and training of minority students will diversify student profile in the department and college and create an inclusive and enriching environment for all. Technical Abstract: Ice recrystallization and growth during freezing storage is a critical challenge that remains to be addressed. Bio-based and safe compounds are urgently needed to avoid the toxicity of synthetic anti-freezing agents. Based on the exciting earlier findings of the investigators’ group, this project aims to investigate ice recrystallization inhibition (IRI) using peptides that are derived from common food proteins through biocatalyzed hydrolysis and amidation reactions. The relationship among peptides’ structure, physicochemical properties, and IRI activity will be established. The fundamental understanding of how peptides’ H-bonding ability and their amphiphilicity affect IRI activity will be gained. The ice-water interfacial behaviors influenced by peptides will be studied using a novel vibrational sum frequency generation spectroscopic method. Therefore, this research addresses what is currently unknown in the field, i.e., how the bio-based peptides’ molecular characteristics relate to their IRI activity. Although theories of IRI have been tested for some pure compounds, little is known about peptide mixtures from common proteins. The structural diversity of proteins and peptides has made the structure-function studies challenging, and this is to be addressed by studying group characteristics in this work. The proposed quantification of H-bond and amphiphilicity as the key factors for IRI activity is a novel angle for IRI research, and the use of advanced spectroscopy will provide new insights on mechanisms of action. Hence, this research demonstrates the use of innovative approaches to identify bio-compatible materials for maintaining quality and integrity of biological systems under freezing conditions. This research will provide transformative experience for graduate students and undergraduate research assistants in their appreciation of how chemistry principles are used in problem-solving. Successful recruitment and training of students with diverse backgrounds will provide an enriching environment in the academic communities within the college and in the local community. Students’ practice of essential skills of critical thinking, problem solving, teamwork, and leadership will lead to the development of future biomaterial researchers and an highly capable and adaptable workforce.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.