Colorimetric determination of p-nitrophenol by using ELISA microwells modified with an adhesive polydopamine nanofilm containing catalytically active gold nanoparticles

Abstract

A microplate method is described for the quantification of p-nitrophenol (p-NPh) in urine samples where it can be found after exposure to certain insecticides such as methyl parathion or paraoxon. The assay is based on the use of a polydopamine (PDA) film doped with gold nanoparticles (AuNPs). The latter exerts a catalytic effect on the reduction of nitrophenols by NaBH4. PDA has adhesive properties and can be used to fix the AuNPs on several solid substrates, here ELISA polystyrene microwells. The optical and catalytic properties of different populations of AuNPs spontaneously grown on PDA films were investigated, mainly in terms of the relationship between AuNPs@PDA nanocomposite preparation and its catalytic activity and stability. The reduction of o-, m-, and p-nitrophenols by NaBH4 in aqueous solution was exploited as model study. The approach demonstrates that useful kinetic information on the catalytic effect can be obtained on 96-wells simultaneously by a conventional ELISA reader at a fixed wavelength of 415 nm. The method was successfully applied to the quantification of p-NPh in (spiked) urine samples and gave high reproducibility (RSD = 3.5%) and a 6.30 µM (836 µg/L) detection limit.

Fluorescence-Based Sensing of Pesticides Using Supramolecular Chemistry

“…Metal-containing organic polymers, or organometallic polymers (Nguyen et al, 2018), have a long history for use in sensing (Kumar et al, 2020a), optoelectronics (Onge et al, 2020), and catalysis (Joshi et al, 2020). They have been used as sensors for a variety of analytes (Xu et al, 2017), including pesticides, using a range of transduction mechanisms, including electrochemical (Wang et al, 2020g), colorimetric (Scarano et al, 2019), and Raman spectroscopybased detection (Yan et al, 2019).…”

Hierarchical drug release designed Au @PDA-PEG-MTX NPs for targeted delivery to breast cancer with combined photothermal-chemotherapy

“…To make AuNPs an ideal drug carrier, they should be modified to achieve targeted delivery and controlled release [ 18 ]. The strong adhesion of polydopamine (PDA) is conductive to its deposition on AuNPs, which can improve the drug loading capacity and biocompatibility, and AuNPs internalisation by mammalian cells [ 19 ]. Moreover, PDA shell can prevent the leakage of loaded drugs during delivery, simultaneously achieving an on-demand drug release in the targeted location, such as NIR stimuli responsive drug release under high temperature or acidic conditions [ 19 – 21 ].…”

Hierarchical Drug Release Designed Au @PDA-PEG-MTX NPs for Targeted Delivery to Breast Cancer with Combined Photothermal-chemotherapy

“…To make AuNPs into perfect drug carriers, modi cation should be performed for targeted delivery and controlled release [18]. The strong adhesion of polydopamine (PDA) is conducive to its deposition in AuNPs, which can improve the drug loading and endow biocompatibility and the ability of AuNPs to enter mammalian cells [19]. Moreover, PDA shell can prevent the leakage of loading drugs during delivery, while achieve an on-demand drug release in the targeted location, such as NIR stimuli responsive drug release under high temperature or acidic conditions [19][20][21].…”

“…The strong adhesion of polydopamine (PDA) is conducive to its deposition in AuNPs, which can improve the drug loading and endow biocompatibility and the ability of AuNPs to enter mammalian cells [19]. Moreover, PDA shell can prevent the leakage of loading drugs during delivery, while achieve an on-demand drug release in the targeted location, such as NIR stimuli responsive drug release under high temperature or acidic conditions [19][20][21]. PEG can also improve the ability of cells to take up gold nanocomposite and prolong the cycle times in plasma [22][23][24].…”