Abstract：
DNA aptamer superparamagnetic photonic crystals (DSPCs), enriched with a highly selective cytosine-rich mismatched single-stranded DNA aptamer (CRDA), were successfully employed in a novel visual detection strategy for the detection of silver ions (Ag+). The technologies of superparamagnetic colloidal nanospheres (SCNs), DNA aptamer, and photonic crystals were combined to fabricate DPSCs. The aptamer was immobilized via electrostatic adsorption with amino groups that were chemically introduced on the surface of the SCNs, forming D-NH-SCNs. The detection is achieved by forming an Ag+ complex (C-Ag+-C) between Ag+ and D-NH-SCN. The DSPCs assembled under a magnetic field by D-NH-SCNs effectively detected Ag+ in the range of 1 μg/L to 5 mg/L, corresponding to the critical concentration range for heavy metals in drinking water. During the detection, the DSPC exhibited a wavelength blueshift from 652.8 nm to 626.4 nm (26.4 nm), as well as changes in reflection intensity. Notably, when detecting Ag+, a change in DSPC color from orange to yellow was observed. In summary, the developed visual detection material facilitates direct Ag + sensing. In the future, different DNA aptamers will be modified further to detect various targets in the fields of medicine, environmental monitoring, and food safety.
摘要：
DNA适体超顺磁性光子晶体(DSPCs),富含高度选择性的富含胞嘧啶的错配单链DNA适体（CRDA），已成功用于检测银离子（Ag）的新型视觉检测策略。超顺磁性胶体纳米球（SCN）的技术，DNA适体,和光子晶体组合以制造DPSC。适体通过静电吸附与化学引入SCN表面的氨基固定，形成D-NH-SCN。通过在Ag+和D-NH-SCN之间形成Ag+络合物(C-Ag+-C)来实现检测。通过D-NH-SCNs在磁场下组装的DSPCs有效地检测到1μg/L至5mg/L范围内的Ag。与饮用水中重金属的临界浓度范围相对应。在检测过程中,DSPC显示波长从652.8nm到626.4nm（26.4nm）的蓝移，以及反射强度的变化。值得注意的是,当检测Ag+时，观察到DSPC颜色从橙色到黄色的变化。总之,开发的视觉检测材料有助于直接Ag+传感。在未来,不同的DNA适体将被进一步修饰，以检测医学领域的各种靶标，环境监测,和食品安全。
