Molecularly Imprinted Silica Nanospheres Embedded CdSe Quantum Dots for Highly Selective and Sensitive Optosensing of Pyrethroids

Abstract

This paper reports the molecularly imprinted polymer (MIP)-based fluorescence nanosensor which is developed by anchoring the MIP layer on the surface of silica nanospheres embedded CdSe quantum dots (QDs) via a surface molecular imprinting process. The molecularly imprinted silica nanospheres (CdSe@SiO 2 @MIP) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), IR spectroscopy, and so forth, which demonstrated the formation of uniform core-shell lambda-cyhalothrin(LC)-imprinted silica nanospheres. The synthesized CdSe@SiO 2 @MIP shows higher photostability, and allows a highly selective and sensitive determination of LC via FL intensity decreasing when removal of the original templates. The CdSe@SiO 2 @MIP was applied to detect trace LC in water without the interference of other pyrethroids and ions. Under optimal conditions, the relative FL intensity of CdSe@SiO 2 @MIP decreased linearly with the increasing LC in the concentration in the range of 0.1-1000 μM with a detection limit (3σ) of 3.6 μg 3 L -1 . It is found that LC can quench the luminescence of CdSe@ SiO 2 @MIP in a concentration-dependent manner that is best described by a Stern-Volmer-type equation. The possible mechanism is discussed.Semiconductor quantum dots (QDs) as high luminescence nanocrystals has attracted considerable attention in recent years, owing to their unique optical and electronic properties, 1,2 such as sharp emission band with broad excitation, and strong resistance to photobleaching. Since Chen and Rosenzweig reported the first practical use of CdS QDs as chemical sensors to determine Zn(II) and Cu(II) ions in aqueous media, 3 a number of QD-based sensors have been reported. [4][5][6][7][8][9][10] For instance, Chen and co-workers have synthesized 15-crown-5 functionalized CdSe/ZnS QDs as a sensing unit toward K þ in aqueous solution. 4 We reported that cyclodextrin modified CdSe/ ZnS QDs allowed a highly sensitive determination of environmental pollutant phenols. 6 Recently, Johnson and coworker have developed a single QD-based aptameric sensor that is capable of sensing the presence of cocaine. 7 Owing to the sustained interest of selective chemo-sensor in environmental monitoring, the design of sensing devices based on QDs is a topic of great interest.In general, surface functionalization is a key to fabricate QD-based probes because of surface modification affording not only the excellent stability of the QDs but also the desired surface binding sites. Among the numerous modifications for QDs, the incorporation of QDs in silica has received considerable attention in the past few years. [11][12][13][14][15] Silica is a good option for the inert material,

Development of a Probe Based on Quantum Dots Embedded with Molecularly Imprinted Polymers to Detect Parathion

“…6). The analyte quenches the fl uorescence of the QD in a concentration dependence in agreement with the Stern-Volmer equation as described in the literature [14,16,25]. The Stern-Volmer formula is given as:…”

“…Parathion-imprinted silica nanosphere embedded CdTe quantum dots were synthesized by modifi ed reverse microemulsion methods [14]. 1.2 mL of Triton X-100 Fig.…”

“…Of polymeric materials, silica with a highly crosslinked rigid matrix and hydrophilic surface has a wide choice of functional precursors and structural forms [14,15]. In this work, we fabricated an imprinted silica matrix embedded with CdTe QDs, which could be adopted to monitor the target molecules by the changes of fl uorescence intensity of CdTe QDs.…”

Molecularly imprinted polymers-coated gold nanoclusters for fluorescent detection of bisphenol A

“…Compared with existing widely used fluorescent probes, especially, quantum dots (QDs) such as CdTe [2,3] and CdSe [4], AuNCs exhibit stronger and more durable fluorescence signals attributing to better resistance to photobleaching and blinking [5]. Therefore, AuNCs have attracted even more attentions and gradually become ideal fluorescent sensor candidates [6][7][8].…”

Molecularly imprinted polymer anchored on the surface of denatured bovine serum albumin modified CdTe quantum dots as fluorescent artificial receptor for recognition of target protein

“…Therefore, if we combine the high selectivity of molecular imprinting technology and excellent fluorescent characteristics of QDs, a new affinity material, with specific recognition cavity and responding to the binding event with significant fluorescence intensity change, could be prepared. However, considerable interest has been focused on the development of small molecules imprinted polymer coated QDs, producing protein imprinted polymer based QDs was still a challenge (Haupt et al, 1998;Carlson et Li et al, 2010;Lin et al, 2004Lin et al, , 2009Liu et al, 2010;Diltemiz et al, 2008;Wang et al, 2009;Zhang et al, 2011).…”