Oxidized Quasi‐Carbon Nitride Quantum Dots Inhibit Ice Growth

Abstract

Antifreeze proteins (AFPs), a type of high-efficiency but expensive and often unstable biological antifreeze, have stimulated substantial interest in the search for synthetic mimics. However, only a few reported AFP mimics display thermal hysteresis, and general criteria for the design of AFP mimics remain unknown. Herein, oxidized quasi-carbon nitride quantum dots (OQCNs) are synthesized through an up-scalable bottom-up approach. They exhibit thermal-hysteresis activity, an ice-crystal shaping effect, and activity on ice-recrystallization inhibition. In the cryopreservation of sheep red blood cells, OQCNs improve cell recovery to more than twice that obtained by using a commercial cryoprotectant (hydroxyethyl starch) without the addition of any organic solvents. It is shown experimentally that OQCNs preferably bind onto the ice-crystal surface, which leads to the inhibition of ice-crystal growth due to the Kelvin effect. Further analysis reveals that the match of the distance between two neighboring tertiary N atoms on OQCNs with the repeated spacing of O atoms along the c-axis on the primary prism plane of ice lattice is critical for OQCNs to bind preferentially on ice crystals. Here, the application of graphitic carbon nitride derivatives for cryopreservation is reported for the first time.

Production, structure–function relationships, mechanisms, and applications of antifreeze peptides

“…The temperatures at which slow growth or decrease of ice crystals are induced by increasing or decreasing the temperature are regarded as the freezing point and melting point, respectively, and the temperature gap between the freezing and melting points is referred to as the THA of the sample (Braslavsky & Drori, 2013). In addition, the nanoliter osmometer method can be used to observe the morphology of single ice crystals, as well as to analyze the effect of AFPs on the morphology of ice crystals (Bai et al., 2017; Caoet al., 2016b; Meister, DeVries, Bakker, & Drori, 2018).…”

Bio-inspired Ice-controlling Materials for Cryopreservation of Cells and Tissues

“…二维碳纳米材料, 例如氧化石墨烯(GO) [54,146] 、氮化 碳量子点(OQCNs) [147][148] 等 [149][150] , 具有高效控制冰晶 成核与生长的作用. 该类纳米材料具有官能团可控、二 维结构稳定、尺寸精确可调控等优点, 是一类全新的仿 生控冰冻存材料 [146] .…”

“…GO 平面由重复的蜂窝状六边形碳环构成; 这种蜂窝状结构可以将 GO 上的羟基排列成与冰晶格匹 配(如图 7A, 7B 所示), 因而可以吸附在冰晶表面, 表现 出明显的抑制冰重结晶、修饰冰晶形貌及热滞后特性, 如图 7C 所示 [146] . 氮化碳量子点(OQCNs)也可以通过类 似的机理与冰晶表面相互作用, 起到抑制冰晶生长的作 用 [147] . 进一步的机理研究表明, 暴露于水中的 OQCNs 上匹配位点的数量决定了其在冰晶上的吸附量, 是影响 其 TH 值的关键因素(图 7D).…”

The Use of Fullerene C60 to Preserve Testicular Tissue after Cryopreservation

“…Some properties of nanoparticles can be useful in solving these problems. For example, oxidized quasicarbon nitride quantum dots can inhibit ice growth/recrystallization through the density of hydrogen bonds formed with ice [2].…”