A molecularly imprinted dual-emission carbon dot-quantum dot mesoporous hybrid for ratiometric determination of anti-inflammatory drug celecoxib

Accepted Manuscript A molecularly imprinted dual-emission carbon dot-quantum dot mesoporous hybrid for ratiometric determination of antiinflammatory drug celecoxib

Mohammad Amjadi, Roghayeh Jalili PII: DOI: Reference:

S1386-1425(17)30824-7 doi:10.1016/j.saa.2017.10.026 SAA 15532

To appear in:

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Received date: Revised date: Accepted date:

24 May 2017 20 September 2017 9 October 2017

Please cite this article as: Mohammad Amjadi, Roghayeh Jalili , A molecularly imprinted dual-emission carbon dot-quantum dot mesoporous hybrid for ratiometric determination of anti-inflammatory drug celecoxib. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Saa(2017), doi:10.1016/ j.saa.2017.10.026

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ACCEPTED MANUSCRIPT A Molecularly Imprinted Dual-Emission Carbon Dot-Quantum Dot Mesoporous Hybrid for Ratiometric Determination of Anti-inflammatory Drug Celecoxib

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Mohammad Amjadi and Roghayeh Jalili*

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Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz

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5166616471, Iran

* Corresponding author Email: [email protected] Tel: +984133393109; Fax: +984133340191

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ACCEPTED MANUSCRIPT Abstract We report on a ratiometric fluorescent sensor based on dual-emission molecularly imprinted mesoporous silica embedded with carbon dots and CdTe quantum dots (mMIP@CDs/QDs) for celecoxib (CLX) as target molecule. The fluorescence of the embedded CDs is insensitive to the

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analyte while the green emissive QDs are selectively quenched by it. This effect is much stronger for the MIP than for the non-imprinted polymer, which indicates a good recognition ability of the

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mesoporous MIP. The hybrid sensor also exhibited good selectivity to CLX over other substances.

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The ratio of the intensity at two wavelengths (F550/F440) proportionally decreased with the increasing of CLX concentration in the range of 0.08- 0.90 µM. A detection limit as low as 57 nM

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the detection of CLX in human serum samples.

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was achieved. Experimental results testified that this sensor was highly sensitive and selective for

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inhibitor Mesoporous silica.

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Keywords: Molecularly imprinted polymer, Quantum dots, Carbon dots, Celecoxib, Cox-2

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ACCEPTED MANUSCRIPT 1. Introduction

As a matter of principle, sensing primarily strives to selectively recognize the target analyte in the presence of interferences. Molecularly imprinted polymers (MIP) and nanomaterials usually

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possess outstanding recognition capabilities. They are generally assembled by polymerization of

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a mixture of functional monomers and cross-linkers in the presence of a template. After

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extraction of the template, cavities which are complimentary in shape, size, and electronic or

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hydrogen-bonding demand remain in the crosslinked polymer matrix, ready to selectively recognize and bind the target molecule [1,2]. MIP has been widely applied in separation[3,4],

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electrochemical sensors [5,6] and biomimetic sensors [7,8].

Colloidal semiconductor quantum dots (QDs) are nanomaterials that exhibit a strong quantum

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confinement effect, which results in size-dependent optical properties. Compared with traditional

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organic dyes, QDs have unique optical advantages such as narrow and symmetric fluorescence peaks with high quantum yield, high resistance to photo- and chemical degradation and

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negligible photobleaching. Furthermore, they have broad and intense absorption bands, which

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allow the excitation of QDs of various sizes or different types at a common wavelength for achieving ratiometric fluorescence detection [9–12]. Carbon dos (CDs) have recently attracted

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considerable attention because of a series of merits such as water solubility, biocompatibility, simple synthesis route, high photo- and chemical stability and tunable excitation and emission spectra. These features make CDs especially useful for fluorescent probes or imaging [13–15]. The hyphenation of QDs and CDs with MIP technology expands the use of fluorescent nanomaterials in sensing and recognition. Currently, most of the reported MIP-modified QD sensors are single wavelength intensity modulation type sensors [16–19]. These sensors are

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ACCEPTED MANUSCRIPT usually affected by some factors, such as concentration change and inhomogeneous distribution of sensors, instrument efficiency, and environmental conditions of the complex samples, which prevent the precise and quantitative determination. In contrast, ratiometric measurement, which involves the simultaneous measurement of fluorescence signals at two or more well-resolved

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wavelengths followed by calculation of their intensity ratio, was devised to circumvent these

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unfavorable effects[20,21]. However, few papers have been reported on the development of

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ratiometric MIP based sensors [22,23] .

Celecoxib (CLX, Fig. 1) is a nonsteroidal anti-inflammatory drug (NSAID) which is a specific

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cyclooxygenase 2 (cox-2) inhibitor approved for relief of the signs and symptoms of

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inflammation associated with rheumatoid arthritis and osteoarthritis [24]. A survey of literature reveals that several analytical methods have been utilized for the quantitative determination of

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CLX in pharmaceutical formulation, human plasma and other samples. These methods include

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voltammetry [25], spectrophotometry[26,27] and chromatography[28,29]. Herein, we use molecularly imprinted mesoporous silica together with QDs and CDs to design

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the ratiometric probe for CLX. The imprinted mesoporous silica hybrid probe shows dual

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emission bands centered at 440 and 550 nm, respectively. Under single wavelength excitation of 360 nm, blue-emitting CDs embedded in silica core, produce reference signals for providing

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built-in correction to avoid environmental effects. Meanwhile green-emitting CdTe QDs embedded in imprinted mesoporous silica shell are selectively quenched by CLX resulting in a ratiometric fluorescent sensor. In the presence of different amounts of CLX, the probe displays continuous color changes from green to blue due to the variations of the dual emission intensity ratios, which can be easily observed by the bare eyes under a UV lamp. By the dual signal

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ACCEPTED MANUSCRIPT amplification method, the sensitivity of mMIP@CD/QD sensor was highly improved and the detection limit was down to nM level.

2. Experimental

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2.1. Materials and apparatus

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All chemicals were of analytical reagent grade and used as-received without further purification.

acid

(TGA,

98%),

sodium

borohydride

(NaBH4,

99%)

and

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thioglycollic

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3-Aminopropyltriethoxysilane (APTES), trisodium citrate, tellurium (reagent powder, 99.999%),

cetyltrimethylammonium bromide (CTAB) were purchased from Merck (Darmstadt, Germany).

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Tetraethoxysilane (TEOS) and cadmium chloride (CdCl2·2H2O, 99.9%) were obtained from Sigma-Aldrich (US). Celecoxib, indomethacin (IND) and meloxicam (MLX) were kindly

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provided by Zahravi Pharmaceutical Co (Tabriz, Iran). CLX stock solution with concentration of

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1.0× 10-3 M was prepared in methanol and stored at 4 °C. Working solutions were prepared daily

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by further dilution of the standard stock solution with water. Britton-Robinson buffer was prepared by mixing phosphoric acid (0.1 M), acetic acid (0.1 M) and boric acid (0.1 M). Buffer

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solutions were adjusted by adding the necessary amount of NaOH in order to obtain the

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appropriate pH. Doubly distilled de-ionized water was used for all the preparations. Fluorescence spectra were recorded using a Shimadzu RF-540 fluorescence spectrophotometer (Kyoto, Japan) equipped with a quartz cell (1 cm×1 cm). The slit widths of the excitation and emission monochromators were both set at 10 nm. UV-vis absorption spectra were obtained by a Cary-100 spectrophotometer (Varian, Sydney, Australia). All optical measurements were carried out under ambient temperature. The size and structure of nanoparticles were characterized by Transmission electron microscopy (TEM) (BioTwin and CM 120, Philips, Netherlands) and

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ACCEPTED MANUSCRIPT scanning electron microscope (SEM) (Mira 3 FEG, Tescan Co., Czech Republic). Fourier transform infrared (FT-IR) measurement was carried out with a Tensor-27 FT-IR spectrometer (Bruker Co., Germany).

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2.2 Synthesis of CdTe QDs and CDs

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CdTe QDs and silane functionalized CDs were synthesized as described in our previous works

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[30, 31]. The details were given in Electronic Supplementary Materials (ESM).

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2.3. One-pot synthesis of dual emission mMIP@CD/QD and mNIP@CD/QD

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Dual emission mMIP@CD/QD nanoparticles were prepared by a sol-gel based method. In a typical process, 20 mL of ethanol and 25 mL of ultrapure water were added to a 250-mL round-

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bottom flask. Under vigorous stirring, 100 µL of CDs and 100 μL of ammonia aqueous solution

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(25%) were injected to the solution. Then, 50 µL of TEOS and 20 mL of ethanol were added drop wise with a constant-pressure dropping funnel, and then the resultant mixture solution was

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stirred for 8 h. 2.0 mL of CdTe QDs, 40 μL of APTES and 10 mg of CLX were dispersed in 30

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mL ethanol and injected to the reaction system and stirred for 20 min. Subsequently, 1.6 mL of CTAB (0.2 M), 0.2 mL of NaOH (0.2 M) and 100 μL of TEOS were added to the above mixture

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and kept stirring for 12 h in darkness at room temperature. The product was collected by centrifugation and washed with water and ethanol several times with the aid of sonication to remove CLX and CTAB. The obtained mMIP@CDs/QDs were re-dispersed in ethanol (100 mL) and stored at 4◦C. Non-imprinted particles (mNIP@CD/QD) as a control to evaluate the molecular recognition properties of imprinted materials were prepared identically, except that the template (CLX) was omitted.

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ACCEPTED MANUSCRIPT 2.4. Analytical procedure

To a 4.0-mL standard cuvette, 200 μL of stock solution of mMIP@CDs/QDs, 300 μL of BrittonRobinson buffer solution (pH=9, 0.12 M), and an appropriate amount of CLX standard or sample

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solution were added and the volume was reached to 3.5 mL with deionized water. After

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incubation for 5 min, the ratios of fluorescence intensities at 550 and 440 nm (F550/F440) were

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2.5. Sample preparation

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measured using excitation wavelength of 360 nm.

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Human serum sample was obtained from Blood Transfusion Center (Tabriz, Iran). A 1.0-mL

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aliquot of each sample was placed into a centrifuge tube and spiked by adding appropriate volumes of CLX standard solution. Then, 0.4 mL of trichloroacetic acid (10% w/w) was added

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into the tube in order to precipitate proteins. After centrifugation for 15 min, the clear

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supernatant was diluted to 10 mL in a volumetric flask and analyzed according to the general

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procedure.

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3. Results and discussion 3.1. Spectral characteristics and structure of mMIP@CDs/QDs Mesoporous silica nanocomposites have suitable structural properties as an imprinting matrix, since their rigid structure is highly suitable for the formation of a delicate recognition site. In addition, their high pore volume and nanosized pore wall thickness guarantee the generation of recognition sites near to the surface and thereby offer high accessibility for target molecules[32]. Herein, the embedding process is carried out by sequential addition of CDs and QDs so that they 7

ACCEPTED MANUSCRIPT were separated in the different spaces of the nanosensor, which prevent the potential energy or electron transfer between them. As shown in Scheme 1, first, the CDs were coated by silica via Stober method to obtain the CD-embedded silica nanoparticles. The silica shell of the CDs prevents their direct contact with CLX, thus providing a reliable reference signal for the

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ratiometric detection. Then the imprinted mesoporous silica shell was prepared on the silica layer

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of the CDs by the co-condensation reaction between TEOS and APTES (functional monomers)

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in the presence of the pore-generating template (CTAB), analyte template (CLX) and CdTe QDs. Subsequently, CTAB and analyte template were removed and mMIP@CD/QD particles were

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obtained. CTAB molecules were used as the template for high yield generation of mesoporous

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structure in silica shell.

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CLX can bind to the imprinted sites on the surface of the hybrid sensor and quenches the green fluorescence intensity of the CdTe QDs probably through photoinduced electron transfer (PET)

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which results in the color change of the total emission from green to blue. To understand the

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possible quenching mechanism, the UV-Vis absorption spectra of QDs and CLX were recorded (Fig. S 1, Electronic Supplementary Material, ESM). As can be seen, the absorption band of

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CLX is close to the band gap of the CdTe QDs, therefore, electrons of the conduction band of

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QDs can transfer to the lowest unoccupied molecular orbital of CLX molecules. Fig. 2 shows the fluorescence emission spectra of CdTe QDs, CDs and mMIP@CD/QD hybrid sensor. The purified CdTe QDs have a symmetric emission peak located at ∼550 nm with a full width at half-maximum (FWHM) of 30 nm (Fig. 2a). When excited at 360 nm, CDs exhibit a strong photoluminescence centered at 440 nm with a FWHM of 80 nm (Fig. 2b). As shown in Fig. 2c, mMIP@CDs/QDs exhibited well resolved dual emission bands under a single wavelength excitation at 360 nm and displayed blue-green fluorescence color (Fig. 2d). 8

ACCEPTED MANUSCRIPT Fig. S2 shows the transmission electron microscope (TEM) image of the prepared CDs, revealing a uniform dispersion without apparent aggregation and a size distribution between 3 and 4 nm. Furthermore, the TEM image in Fig. S3 shows that original CdTe QDs are spherical

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and monodispersed in nanometer scale (estimated average diameter of 2.4).

The TEM image of mMIP@CDs/QD is shown in Fig. 3a. From this image, the uniform quasi-

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spherical particle structure with an average diameter about 200 nm could be observed. SEM

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results (Fig. 3b) provide further support for uniform structure and spherical morphology of

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3.2. Optimization of synthesis conditions

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mMIP@CDs/QD. The porous structure is also seen from this picture.

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In order to achieve a successful molecular imprinting, the suitable polymerization conditions,

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such as loading quantity of QDs and amounts of TEOS and APTES should be selected. As seen in Table 1 the polymers that employed 100 μL of TEOS as the cross-linker have relatively better

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imprinting factor for CLX. The doping ratio of QDs and CDs had important influence to the

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ratiometric detection, so MIPs with different doping ratios were prepared. The results indicated that both the linear range and detection limit varies with variation of the CdTe QDs proportion. When QDs were in a large proportion, the linear range was limited because the strong intensity of QDs masked the emission of CDs (reference peak). In the meanwhile, overmuch increase of CDs also narrowed the linear range because of low intensity of CdTe QDs. The probe is the most sensitive when 2-3 mL QDs solution and 100 μL of CDs were used.

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ACCEPTED MANUSCRIPT The effect of APTES amount on the selectivity of probe was also investigated within the range of 10-80 μL. As shown in Fig. 4 optimum selectivity (IF) was obtained with 40 μL of APTES. Small amounts of monomer could not react adequately with the template and would not create enough recognition sites, while excessive monomer may cause homogeneous self-condensation

3.3. Analytical performance of mMIP@CD/QD sensor

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and leads to the formation of fewer recognition sites [33].

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The response of the dual-emission fluorescent probe towards CLX was investigated. Firstly,

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assay conditions such as the dispersion medium, response time, pH value, buffer system, and amount of probe which may affect the fluorescence quenching efficiency, were optimized using

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quenching ratio defined as F550/F440 (or FQDs/FCDs).

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The dispersion medium was first studied and water, water-ethanol and ethanol were tested. As shown seen in Fig. S4. The quenching ratio increased with the increase of ethanol. Therefore,

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ethanol was selected as the dispersion medium.

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The fluorescence of the dual-emission mMIP@CDs/QDs at different pH was also tested. The fluorescence intensity ratio (F550/F440) in the absence of CLX was not affected by pH changes in

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the range of 6.0−9.0. The effect of pH on the fluorescence intensity ratio in the presence of CLX (0.5 µM) was then studied. The highest fluorescence quenching (Table 2) was observed at pH 9, therefore, this pH was selected for further experiments and Britton-Robinson buffer was used to adjust the pH. The pH value affected not only the charge of the binding sites on MIP but also the charge of CLX.

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ACCEPTED MANUSCRIPT To ensure the completion of binding between CLX and the recognition sites of mMIP@CDs/QDs, the effect of incubation time between CLX and mMIP@CDs/QDs was investigated. As shown in Fig. S5, when the CLX concentration was fixed at 0.5 µM the fluorescence intensity ratio decreased rapidly with increasing time in the initial 5 min, after

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which the reaction reached equilibrium and the curve became flat. Therefore, 5 min was selected

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as a suitable incubation time for next experiments. Compared to non-mesoporous surface

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imprinted QDs which normally need 15–60 min to reach adsorption equilibrium, this sensor has an extraordinary rapid response [34-36]. This is attributed to the generation of recognition sites

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between the pores of the mesoporous silica which offered high accessibility of template

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molecules.

The effect of amount of mMIP@CD/QD naoparticles was also studied by changing their volume

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from 100 to 400 µL. The results indicated that the amount of mMIP@CD/QD in the solution

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greatly affects the detection sensitivity and linear range for CLX assay. The fluorescence intensity of the solution changed very slightly, when a small amount of CLX was added to the

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solution with high amount of mMIP@CD/QD. A wider concentration range and lower detection

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limit appeared at 200 µL (Fig. S6). Therefore, the amount of mMIP@CD/QD was fixed at 200 µL throughout the work.

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As shown in Fig. 5a, the fluorescence intensity of the CdTe QDs at 550 nm gradually decreased upon addition of CLX whereas the blue fluorescence of CDs remained constant. As the intensity ratio of the two emissions decreased, the fluorescence color of the probe solution changed from green to blue, which was easily observed. The ratio of the fluorescence intensity is closely related to the amount of CLX. (Fig. 5b). There is a good linear relationship (R = 0.9959) between the logarithm of the intensity ratios and the concentrations of CLX in the range from 0.08 to 0.9

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ACCEPTED MANUSCRIPT μM with a 57 nM detection limit (signal-to-noise ratio of 3). The dose response of the mesoporous structured ratiometric NIPs to CLX also has been examined. From Fig. 5b, we can see that fluorescence intensity of NIPs also can be quenched by CLX. But, the sensitivity was much lower and the linear range was narrower (0.2−0.8 μM with a detection limit of 115nM).

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Comparison of the proposed method with some other reported analytical methods for the CLX

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quantification is shown in Table 2. As can be seen the developed sensor has better or comparable

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analytical performance compared with most of other reported methods. High sensitivity of this sensor is due to the using the ratimetric fluorescence technique and mesoporous silica as

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imprinting matrices. And also in proposed ratiometric sensor, the changes of fluorescence color

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ratios can be used for visual sensing applications for CLX (Fig. 5c).

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3.4. Selectivity and interferences study

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The selectivity of mMIP@CDs/QDs was demonstrated by comparing its response to CLX with that obtained for two other NSAID drugs, namely meloxicam and indomethacin (Fig. 1). The

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fluorescence intensity ratios of NIP and MIP are presented in Fig. 6. For NIP, the fluorescence

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intensity ratios in all cases were nearly identical. The different fluorescence intensity ratios of MIP could be due to the functional group variation from the molecular imprinted cavities. So the imprinted cavity of mMIP@CDs/QDs is not suitable to accommodate other NSAID drugs, which results in the selective response to CLX. Furthermore, to demonstrate the selectivity of this proposed sensor for analysis of complex biological samples, an extensive interference study was carried out. The tolerable limits of coexisted species were taken as a concentration that produces a relative error not larger than 5%. 12

ACCEPTED MANUSCRIPT As seen from Table 4, the mMIP@CD/QD sensor showed high selectivity to CLX against not only metal ions but also amino acids and some other bioactive substances. The negligible interference from other substances suggests the applicability of the probe for detection of CLX in

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biological samples.

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3.5. Analysis of real samples

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The application of the mMIP@CD/QD as an optosensing material was further demonstrated for

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the detection of CLX in human serum samples. Recovery studies were carried out by spiking the samples with CLX in the concentration range of 1.0-5.0 µM. A summary of the calculated mean

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CLX concentration for each sample is shown in Table 5. The obtained recoveries ranged from

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96.9 % to 102.3 %, which indicated the usefulness of the mMIP@CD/QD for the determination

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of CLX in real samples.

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6. Conclusions

A simple and effective strategy for designing ratiometric and imprinted fluorescent nanosensor for CLX has been described. CDs were loaded into the core and CdTe QDs were encapsulated in the outer molecularly imprinted mesoporous shell. Fluorescence of CDs serve as reference signal while the fluorescence of CdTe QDs embedded in imprinted silica shell is selectively quenched by CLX. Indeed, by combining the excellent selectivity of MIP, the efficient properties of ratiometric technique and sensitivity of mesoporous silica, a new sensor for selective recognition 13

ACCEPTED MANUSCRIPT and quantitative determination of target analyte has been developed. This dual emission hybrid sensor has good selectivity to CLX over other species and similar drugs. Moreover, the sensor was successfully applied for the detection of CLX in spiked serum samples.

W. Wan, M. Biyikal, R. Wagner, B. Sellergren, K. Rurack, Angew. Chemie - Int. Ed. 52

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ACCEPTED MANUSCRIPT Table 1. Effect of composition of mMIP@CDs/QD on imprinting factor.

Polymer

CDs(µL)

CdTe QDs(mL)

TEOS (µL)

(F0/F)

100

1

50

1.13

II

100

1

100

1.24

III

100

2

50

IV

100

2

V

100

3

VI

100

3

IP US

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100

AN M ED PT CE AC

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1.36 1.9

50

1.5

100

1.69

ACCEPTED MANUSCRIPT Table 2. Effect of pH on the quenching efficiency. The concentration of CLX is 0.5 µM. F550/F440

6

0.95

7

0.9

8

0.89

9

0.83

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pH

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ACCEPTED MANUSCRIPT Table3. Analytical characteristics of some published methods for determination CLX. LOD (μM)

Linear range (μM)

Ref.

0. 027

0.1-3.4

[37]

spectrophotometry

1.5

15.7-57.7

UV spectrophotometry

0.68

2.6-52

[38]

LC–MS/MS

0.01

0.01-10.49

[39]

Spectrofluorimetry

0.019

0.26-10.5

[40]

mMIP@CD/QD sensor

0.057

0.08-0.90

This work

Method

Excitation–Emission Matrix

AC

CE

PT

ED

M

AN

US

CR

IP

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Fluorescence Spectroscopy

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[26]

ACCEPTED MANUSCRIPT Table4. Tolerance limits of some potentially interfering species in the determination of 0.5 µM CLX under optimum condition Interfering species

Tolerance limit (interfering to analyte ratio)

100

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Sucrose, Glucose, Lactose, Uric acid, Ascorbic acid, Tryptophan, Alanine,

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L-Cysteine, Glycine, Creatinine, Vitamin B1,

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Dopamine, Epinephrine, Na+, K+,Mg2+, Zn2+,

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Ca2+, NH4 +, Cl-, SO42- ,PO43-

50

M

Zn2+ , Se2+, Fe3+, Al3+, Vitamin B2

10

AC

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Cu2+

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ACCEPTED MANUSCRIPT Table 5. Results for the determination of CLX in serum samples.

Added (μM)

Samples

Found (μM)

Recovery (%)

Human serum(II)

3.0

3.1±2.1

5.0

5.0±0.6

1.0

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0.99 ± 0.7

98.8

CR

1.0

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Human serum(I)

AN

T

Mean ± RSD (n=3)

98

3.06±2.8

101.8

4.84 ±2.6

AC

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PT

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5.0

99.3

0.98 ± 0.5

M

3.0

102.3

22

96.9

ACCEPTED MANUSCRIPT Captions to figures Scheme 1 Schematic illustration of the architecture of the mMIP@CDs/QDs Hybrid sensor and the working principle for the detection of CLX. Fig.1. Chemical structure of (a) Celecoxib, (b) Indomethacin, (c) Meloxicam

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Fig. 2. Fluorescence emission spectra of (a) CdTe QDs, (b) CDs and (c) mMIP@CDs/QDs under

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a single wavelength excitation at 360 nm. (d) Fluorescence color of mMIP@CDs/QDs under a

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UV lamp.

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Fig.3 (a) TEM image and (b) SEM image of mMIP@CDs/QDs.

Fig. 4. Effect of the amounts of APTES on the imprinting factor of mMIP@CDs/QDs. (Error

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bars represent one standard deviation for three measurements)

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Fig.5. (a). Fluorescence spectra of mMIP@CDs/QDs at different concentrations of CLX; (b) The linear calibration graph between Log [(F550/F440)0 / (F550/F440)] and the CLX concentration using

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mMIP@CDs/QDs and mNIP@CDs/QDs; (Error bars represent one standard deviation for three

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measurements) (c) The color changes of the dual emission mMIP@CDs/QDs upon the addition of CLX under a UV lamp.

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Fig.6. Quenching constant of mMIP@CDs/QDs and mNIP@CDs/QDs for CLX, IND, MLX.

AC

(Error bars represent one standard deviation for three measurements)

23

ACCEPTED MANUSCRIPT

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Scheme 1

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ACCEPTED MANUSCRIPT Fig. 1 CH3 H2N

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N

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(a)

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F

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F

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Cl

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N O OH

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O

S N

AC

CE

(b)

OH

O

NH N O

S O

(c)

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Fig.2

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Fig.3a

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Fig.4

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Fig.5a

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Fig. 5b

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Fig. 5c

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Fig.6

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ACCEPTED MANUSCRIPT

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Graphical abstract

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ACCEPTED MANUSCRIPT Highlights

A ratiometric fluorescent probe was developed for celecoxib.

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Excellent selectivity was guaranteed by molecular imprinting.

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CE

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M

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IP

The probe showed high sensitivity and rapid response towards celecoxib.

33