Abstract：
BACKGROUND: The aggregation of isotropic particles through interparticle reactions poses a challenge in control due to the ability of all surfaces to bind to each other, rendering the quantitative detection of such interparticle reactions based on particle size difficult. Here, we proposed a novel detection scheme for DNA utilizing an assembly of Janus particles (JPs) employing dynamic light scattering (DLS). DNA molecules are tethered on one hemisphere of the JP, while the other hemisphere retains its hydrophobic properties.
RESULTS: Aggregation of JPs was induced by the sandwich hybridization of target DNA between them. The assembly of JPs was effectively monitored by the changes in hydrodynamic diameter detected by DLS, revealing that aggregation peaks at 2-3 particles and further reaction was hindered due to the inability of one hemisphere of the JP to interact with another JP. The target DNA demonstrated detectability at concentrations as low as several tens of pM to several nM using a digital sensing method. The two types of target DNA, such as simple (14 base pairs) and HIV-2 specific sequences (20 base pairs) were detectable at nM and pM levels, respectively. Moreover, we substantiated the robustness of our detection scheme through stoichiometric calculations based on an equilibrium model. The present detection mechanism was well explained based on the binding affinity of DNA hybridization.
CONCLUSIONS: This detection method harnesses the anisotropic nature of JPs and represents the first detection approach based on aggregation. By altering the modification molecules on JPs to match target molecules, such as proteins and organic compounds, a wide range of versatile molecules can be detected using this scheme with high sensitivity. This underscores the broad applicability of the present method.
RESULTS: Aggregation of JPs was induced by the sandwich hybridization of target DNA between them. The assembly of JPs was effectively monitored by the changes in hydrodynamic diameter detected by DLS, revealing that aggregation peaks at 2-3 particles and further reaction was hindered due to the inability of one hemisphere of the JP to interact with another JP. The target DNA demonstrated detectability at concentrations as low as several tens of pM to several nM using a digital sensing method. The two types of target DNA, such as simple (14 base pairs) and HIV-2 specific sequences (20 base pairs) were detectable at nM and pM levels, respectively. Moreover, we substantiated the robustness of our detection scheme through stoichiometric calculations based on an equilibrium model. The present detection mechanism was well explained based on the binding affinity of DNA hybridization.
CONCLUSIONS: This detection method harnesses the anisotropic nature of JPs and represents the first detection approach based on aggregation. By altering the modification molecules on JPs to match target molecules, such as proteins and organic compounds, a wide range of versatile molecules can be detected using this scheme with high sensitivity. This underscores the broad applicability of the present method.
摘要：
背景：由于所有表面彼此结合的能力，各向同性颗粒通过颗粒间反应的聚集对控制提出了挑战，使基于颗粒大小的这种颗粒间反应的定量检测变得困难。这里,我们提出了一种新颖的DNA检测方案，利用动态光散射（DLS）的Janus颗粒（JP）组装。DNA分子束缚在JP的一个半球上，而另一个半球保持其疏水特性。
结果：目标DNA的夹心杂交诱导了JPs的聚集。通过DLS检测到的流体动力学直径的变化，有效地监控了JP的组装。揭示了2-3个颗粒处的聚集峰和进一步的反应由于JP的一个半球不能与另一个JP相互作用而受到阻碍。使用数字传感方法，靶DNA在低至几十pM至几nM的浓度下显示出可检测性。目标DNA的两种类型,例如简单的（14个碱基对）和HIV-2特异性序列（20个碱基对）在nM和pM水平是可检测的，分别。此外，我们通过基于平衡模型的化学计量计算证实了我们的检测方案的鲁棒性。基于DNA杂交的结合亲和力，可以很好地解释本检测机制。
结论：该检测方法利用了JP的各向异性性质，代表了基于聚集的第一种检测方法。通过改变JP上的修饰分子以匹配目标分子，如蛋白质和有机化合物，使用该方案可以高灵敏度地检测到多种通用分子。这强调了本方法的广泛适用性。
结果：目标DNA的夹心杂交诱导了JPs的聚集。通过DLS检测到的流体动力学直径的变化，有效地监控了JP的组装。揭示了2-3个颗粒处的聚集峰和进一步的反应由于JP的一个半球不能与另一个JP相互作用而受到阻碍。使用数字传感方法，靶DNA在低至几十pM至几nM的浓度下显示出可检测性。目标DNA的两种类型,例如简单的（14个碱基对）和HIV-2特异性序列（20个碱基对）在nM和pM水平是可检测的，分别。此外，我们通过基于平衡模型的化学计量计算证实了我们的检测方案的鲁棒性。基于DNA杂交的结合亲和力，可以很好地解释本检测机制。
结论：该检测方法利用了JP的各向异性性质，代表了基于聚集的第一种检测方法。通过改变JP上的修饰分子以匹配目标分子，如蛋白质和有机化合物，使用该方案可以高灵敏度地检测到多种通用分子。这强调了本方法的广泛适用性。
