“两面神”型金纳米粒子比色检测铁离子的新方法

制备了一种聚乙二醇(PEG)和柠檬酸根不对称修饰的"两面神"型金纳米粒子(Janus AuNPs)比色传感器,并基于此建立了铁离子(Fe³⁺)比色检测的新方法。首先,利用柠檬酸钠还原法制备了粒径相对较大的金纳米粒子,随后,以玻片为基底,将大粒径金纳米粒子修饰在玻片上,利用玻片掩蔽部分柠檬酸根位点,并进一步在金纳米粒子非接触区域上修饰大量PEG链,得到柠檬酸根和PEG不对称修饰的Janus AuNPs。引入Fe³⁺后,有限区域内的柠檬酸根诱导Janus AuNPs发生定向聚集,形成金纳米粒子寡聚体并在水溶液中保持稳定。Janus AuNPs溶液吸光度比值与Fe³⁺浓度在1μmol/L～10 mmol/L范围内呈线性变化(y=0.129x+0.317),检出限为715 nmol/L。与同类方法相比,该方法操作简便、灵敏度高,且可极大拓宽检测的线性范围。

A Novel Colorimetric Detection Method for Iron Ion Based on Janus Gold Nanoparticles

A novel colorimetric method for iron ion (Fe 3+) detection was proposed by using asymmetrically modified Janus gold nanoparticles (Janus AuNPs ) in this paper.Initially,citrate-stabilized AuNPs with relatively large size were prepared through reduction reaction. Then,the large sized citrate-stabilized AuNPs were immobilized on the glass slide,through which some binding sites on the surface of AuNPs were concealed.The stabilizing agent of polyethylene glycol (PEG ) was further introduced onto the exposed surface of AuNPs to obtain the PEG and citrate asymmetrically modified Janus AuNPs.After the introduction of Fe 3+,the aggregation behavior of Janus AuNPs was adjusted in an oriented and controllable manner to form oligomers which could remain stable in aqueous solution for a long time.Such an asymmetrical modification could significantly improve the dynamic detection range (1 μmol/L-10 mmol/L ) of AuNPs based colorimetric assay.Meanwhile,a linear calibration curve,i.e. A 750 / A 536 =0.129 c (μmol/L )+0.317 was also obtained,with a detection limit of 715 nmol/L.Compared with other nanoparticle-based colorimetric system for Fe ^3+ detection,this method is simple and sensitive,and surprisingly broadens the linear range for detection.