Biological relevance of oxidative debris present in as-prepared graphene oxide.
Biological relevance of oxidative debris present in as-prepared graphene oxide.
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DOI：
10.1039/c5ra10306a
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发表时间：
2015-01-01
期刊：
影响因子：
3.9
通讯作者：
Kumar CV
中科院分区：
文献类型：
--
作者：
Pattammattel A;Williams CL;Pande P;Tsui WG;Basu AK;Kumar CV
本文报道了氧化石墨烯（GO）悬浮液中存在的氧化碎片（OD）对蛋白质的影响及其对人胚肾细胞（HEK-293 T）的毒性。通过用氨水重复洗涤除去OD以产生相应的碱洗GO（bwGO）。碱洗后牛血清白蛋白（BSA）的载量（w/w）增加了85%，而血红蛋白（Hb）和溶菌酶（Lyz）的载量分别下降了160%和100%。用紫外圆二色谱法比较了13种不同的结合到bwGO的蛋白质与相应的结合到GO的蛋白质的二级结构。与结合到GO的蛋白质相比，bwGO的蛋白质二级结构有一致的损失，但没有观察到蛋白质的等电点或疏水性与结构损失的程度之间的相关性。所有与bwGO和GO结合的酶均表现出显着的活性，并且无论是否存在OD，酶活性与结构保留程度之间都存在强相关性。在低载量（<100 μg/mL）下，GO和bwGO均显示出优异的细胞活力，但在高载量（>100 μg/mL）下观察到显著的细胞毒性（约40%细胞死亡）。在对照研究中，OD本身并没有改变生长速率，即使在48小时的孵育。因此，GO中OD的存在在控制蛋白质-GO界面的化学和生物学性质方面起着非常重要的作用，并且与bwGO相比，GO中OD的存在改善了其生物相容性。
The influence of oxidative debris (OD) present in as-prepared graphene oxide (GO) suspensions on proteins and its toxicity to human embryonic kidney cells (HEK-293T) are reported here. The OD was removed by repeated washing with aqueous ammonia to produce the corresponding base-washed GO (bwGO). The loading (w/w) of bovine serum albumin (BSA) was increased by 85% after base washing, whereas the loading of hemoglobin (Hb) and lysozyme (Lyz), respectively, was decreased by 160% and 100%. The secondary structures of 13 different proteins bound to bwGO were compared with the corresponding proteins bound to GO using the UV circular dichroism spectroscopy. There was a consistent loss of protein secondary structure with bwGO when compared with proteins bound to GO, but no correlation between either the isoelectric point or hydrophobicity of the protein and the extent of structure loss was observed. All enzymes bound to bwGO and GO indicated significant activities, and a strong correlation between the enzymatic activity and the extent of structure retention was noted, regardless of the presence or absence of OD. At low loadings (<100 μg/mL) both GO and bwGO showed excellent cell viability but substantial cytotoxicity (~40% cell death) was observed at high loadings (>100 μg/mL). In control studies, OD by itself did not alter the growth rate even after a 48-h incubation. Thus, the presence of OD in GO played a very important role in controlling the chemical and biological nature of the protein-GO interface and the presence of OD in GO improved its biological compatibility when compared to bwGO.