A new fluorimetric method for determination of valproic acid using TGA-capped CdTe quantum dots as proton sensor

Methotrexate (MTX), a folic acid derivative, is a potent anticancer used for treatment of different malignancies, but possible initiation of drug resistance to MTX by cancer cells has limited its applications. Nanoconjugates (NCs) of MTX to quantum dots (QDs) may favour the cellular uptake via folate receptors (FRs)-mediated endocytosis that circumvents the efflux functions of cancer cells. We synthesised MTX-conjugated l-cysteine capped CdSe QDs (MTX-QD nanoconjugates) and evaluated their internalisation and cytotoxicity in the KB cells with/without resistancy to MTX. The NCs were fully characterised by high resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and optical spectroscopy. Upon conjugation with MTX, the photoluminescence (PL) properties of QDs altered, while an obvious quenching in PL of QDs was observed after physical mixing. The MTX-QD nanoconjugates efficiently internalised into the cancer cells, and induced markedly high cytotoxicity (IC50, 12.0 µg/mL) in the MTX-resistant KB cells as compared to the free MTX molecules (IC50,105.0 µg/mL), whereas, these values were respectively about 7.0 and 0.6 µg/mL in the MTX-sensitive KB cells. Based on these findings, the MTX-QD nanoconjugates are proposed for the targeted therapy of MTX-resistant cancers, which may provide an improved outcome in the relapsed FR-overexpressing cancers.

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“…Similar phenomena were observed in a previous study for the synthesis of thioglycolic acid-capped CdTe QDs [70].…”

Section: Discussionsupporting

confidence: 89%

Methotrexate-conjugated quantum dots: synthesis, characterisation and cytotoxicity in drug resistant cancer cells

Johari-Ahar

Barar

Alizadeh

et al. 2015

Journal of Drug Targeting

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“…For this purpose analytical techniques have been used. Numerous methodologies have been described for determining VAL such as gas chromatography (GC) coupled with mass spectrometry (MS), 2,8−10 GC-flame ionization detector (FID), 11,12 liquid chromatography (LC)-MS, 13−15 high performance liquid chromatography (HPLC)-MS, 16,17 HPLC-fluorescence methods, 1,18 HPLC-electrochemical detection (ECD), 19 ultra-performance liquid chromatography (UPLC)-MS, 20 and capillary electrophoresis (CE) with a contactless conductivity detector. 21,22 Some biosensor studies were also performed to determine VAL.…”

Section: Introductionmentioning

confidence: 99%

Square wave voltammetric determination of valproic acid in pharmaceutical Preparations

Acar¹,

Onar²

2016

Turk J Chem

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The electrochemical behavior of valproic acid (VAL) was investigated using square wave voltammetry, cyclic voltammetry, and sampled direct current polarography and a new square wave voltammetric method was developed for determination of VAL in pharmaceutical preparations. VAL showed two reduction peaks at about-0.2 V and-0.8 V vs. Ag/AgCl 3 M KCl with a hanging mercury drop electrode in 0.05 M pH 3.3 Britton-Robinson (BR) buffer. These peaks were named peak I and peak II, respectively. The types of limiting current of both peaks were determined as diffusion controlled based on cyclic voltammetry studies. A linear calibration graph was obtained in the range 1.46 × 10 −4-1.0 × 10 −3 M. The limit of detection (LOD) and limit of quantification (LOQ) were 1.09 × 10 −4 M (21.05 µ g/mL) and 1.10 × 10 −4 M (144.20 µ g/mL), respectively. Recovery studies for the accuracy of the method were performed by adding known amounts of VAL and it was found to be 109.67 ± 4.85%. The proposed method was successfully applied to pharmaceutical products on the market.

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“…Introduction: Cadmium telluride (CdTe), one of the groups of II-VI compounds and with a direct bandgap of 1.54 eV, has been extensively investigated because of its excellent electronic and optical properties. CdTe quantum dots (QDs) are of special interest because of broad applications in solar cells [1], photocatalysis [2], chemo-sensing [3], bio-imaging [4] and so on. Up to now, two successful routes [5,6] for the synthesis of CdTe QDs have been developed, but each of them has its own advantages and disadvantages.…”

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confidence: 99%

Aqueous synthesis of luminescent cadmium telluride quantum dots using ascorbic acid as the reducing agent

Xie

Liu

et al. 2014

Micro & Nano Letters

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A facile method for the synthesis of highly luminescent cadmium telluride (CdTe) quantum dots (QDs) in an aqueous solution is presented. Ascorbic acid and sodium tellurite were used as the reducing agent and tellurium source, respectively, to synthesise CdTe QDs under mild conditions. In this method, the preparation of the Te precursor and the growth of CdTe QDs were achieved with a one-step synthetic route. CdTe QDs with five different emission wavelengths of 506, 517, 541, 564 and 575 nm were obtained by tuning the refluxing time. The quantum yields of these QDs were 5.4, 10.9, 37.4, 53.3 and 40.1%, respectively. The X-ray powder diffraction and transmission electron microscopy characterisation indicated that the obtained QDs had a pure cubic zinc blended structure with spherical shape. The main advantage of the present method is that both the reducing agent and tellurium precursor are stable and cheap. Furthermore, no toxic gases are released in the preparation process. It is a low cost and green method suitable for large-scale synthesis.

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A new fluorimetric method for determination of valproic acid using TGA-capped CdTe quantum dots as proton sensor

Cited by 22 publications

References 33 publications

Methotrexate-conjugated quantum dots: synthesis, characterisation and cytotoxicity in drug resistant cancer cells

Methotrexate-conjugated quantum dots: synthesis, characterisation and cytotoxicity in drug resistant cancer cells

Square wave voltammetric determination of valproic acid in pharmaceutical Preparations

Aqueous synthesis of luminescent cadmium telluride quantum dots using ascorbic acid as the reducing agent

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