Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Analytical & Testing Centre , Sichuan University , 29 Wangjiang Road , Chengdu , Sichuan 610064 , China.
Department of Chemistry, Centre for Biotechnology , Brock University , 1812 Sir Isaac Brock Way , St. Catharines , Ontario L2S 3A1 , Canada.
Anal Chem. 2020 Feb 18;92(4):3220-3227. doi: 10.1021/acs.analchem.9b04964. Epub 2020 Jan 28.
Colloidal nanoparticle biosensors capable of on-particle biocatalysis are powerful tools for amplified detection of biomolecules. The development and practical uses of such concentric amplifiers can be complicated because of the on-particle biorecognition that involves varying interfacial factors at the biomolecule-nanoparticle interfaces. Herein, we reason that a nanoparticle biosensor equipped with an in-solution biorecognition element may be better fabricated, predicted, controlled, and performed. The in-solution biorecognition shall also be streamlined with the on-particle biocatalysis so that the overall analytical and kinetic performance is not compromised. As a testbed, we introduce a concentric DNA amplifier driven by an enzyme-powered three-dimensional DNA nanomachine, where a DNA walker can be instantly assembled onto a spherical nucleic acid (SNA) track through a polyadenosine anchor. As such, the free DNA walker can participate in reactions in a homogeneous solution before assembling to the SNA track. The instant and stable assembly enabled by both adsorption and complementary base pairing also ensures rapid on-particle biocatalysis. We demonstrate that the in-solution biorecognition effectively eliminates the binding hindrance encountered by the on-particle biorecognition and thus significantly reduced energy barriers for the detection of nucleic acids and proteins. Because of the in-solution biorecognition, our system can also be plugged readily into complex DNA strand displacement networks for rapid signal amplification.
能够进行粒子内生物催化的胶态纳米颗粒生物传感器是用于放大检测生物分子的有力工具。由于涉及到生物分子-纳米颗粒界面处变化的界面因素，这种同心放大器的开发和实际应用可能会很复杂。在此，我们认为配备溶液内生物识别元件的纳米颗粒生物传感器可能更容易制造、预测、控制和执行。溶液内生物识别也应与粒子内生物催化相协调，以确保整体分析和动力学性能不受影响。作为一个试验台，我们引入了一种由酶驱动的三维 DNA 纳米机器驱动的同心 DNA 放大器，其中 DNA walker 可以通过多腺苷酸锚瞬间组装到球形核酸 (SNA) 轨道上。因此，游离的 DNA walker 可以在组装到 SNA 轨道之前参与均相溶液中的反应。吸附和互补碱基配对所实现的即时和稳定组装也确保了快速的粒子内生物催化。我们证明，溶液内生物识别有效地消除了粒子内生物识别所遇到的结合障碍，从而显著降低了检测核酸和蛋白质的能垒。由于溶液内生物识别，我们的系统还可以轻松地插入复杂的 DNA 链置换网络中，以实现快速信号放大。
