Wu Rong, Peng Huaping, Zhu Jun-Jie, Jiang Li-Ping, Liu Juewen
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada.
Front Chem. 2020 Feb 25;8:121. doi: 10.3389/fchem.2020.00121. eCollection 2020.
DNA-functionalized gold nanoparticles (AuNPs) have been widely used in directed assembly of materials, biosensors, and drug delivery. This conjugate may encounter proteins in these applications and proteins may affect not only DNA adsorption but also the function of the attached DNA. Bovine serum albumin (BSA) with many cysteine residues can strongly adsorb on AuNPs and this conjugate showed high colloidal stability against salt, acid and base. Similar protection effects were also observed with a few other common proteins including catalase, hemoglobin, glucose oxidase, and horseradish peroxidase. DNA oligonucleotides without a thiol label can hardly displace adsorbed BSA, and BSA cannot displace pre-adsorbed DNA either, indicating a strongly kinetically controlled system. Thiolated DNA can be attached at a low density on the AuNPs with a BSA corona. The BSA corona did not facilitate the hybridization of the conjugated DNA, while a smaller peptide, glutathione allowed faster hybridization. Overall, proteins increase the colloidal stability of AuNPs, and they do not perturb the gold-thiol bond in the DNA conjugate, although a large protein corona may inhibit the hybridization function of DNA.
DNA功能化金纳米颗粒（AuNPs）已广泛应用于材料的定向组装、生物传感器及药物递送领域。在这些应用中，这种共轭物可能会遇到蛋白质，而蛋白质不仅可能影响DNA的吸附，还会影响附着DNA的功能。具有许多半胱氨酸残基的牛血清白蛋白（BSA）能够强烈吸附在AuNPs上，并且这种共轭物对盐、酸和碱表现出高胶体稳定性。在包括过氧化氢酶、血红蛋白、葡萄糖氧化酶和辣根过氧化物酶在内的其他一些常见蛋白质中也观察到了类似的保护作用。没有硫醇标签的DNA寡核苷酸很难取代吸附的BSA，并且BSA也不能取代预先吸附的DNA，这表明这是一个受动力学强烈控制的体系。硫醇化DNA可以以低密度附着在带有BSA冠层的AuNPs上。BSA冠层不利于共轭DNA的杂交，而较小的肽谷胱甘肽则能使杂交更快进行。总体而言，蛋白质增加了AuNPs的胶体稳定性，并且它们不会干扰DNA共轭物中的金-硫醇键，尽管大的蛋白质冠层可能会抑制DNA的杂交功能。
