Phosphatidylcholine determination in dietary supplement by coupled enzymes immobilized in a single bioreactor

A photoelectrochemical biosensor based on SnO2 nanoparticles for phosphatidylcholine detection in soybean oil

A photoelectrochemical (PEC) biosensor based on SnO₂ nanoparticles (SnO₂ NPs) was developed and applied for phosphatidylcholine (PC) detection in soybean oil. SnO₂ NPs were grown on an indium tin oxide (ITO) electrode, polythionine (PTh) was electropolymerized on the surface of ITO/SnO₂ NPs, and choline oxidase (ChO_x) was immobilized to prepare the ITO/SnO₂ NPs/PTh/ChO_x electrode. The developed PEC biosensor can detect PC under visible light irradiation. The experimental conditions for PC detection were as follows: 1.8 mg mL^-1 ChO_x concentration, 0.5 V bias voltage, 18 mW cm^-2 light intensity, and pH 6. The PEC biosensor had a detection limit of 0.005 mM (S/N = 3) and a detection range from 0.03 mM to 4 mM. This PEC biosensor based on SnO₂ NPs was applied to detect PC in soybean oil. The recovery rate tested by the standard addition method was 95.2-107.4%. These findings were consistent with the results obtained by high-performance liquid chromatography (HPLC). Therefore, the proposed PEC biosensor based on SnO₂ NPs has excellent reproducibility, stability, and great potential applications in the PEC analysis of PC in soybean oil.

Visualization analysis of lecithin in drugs based on electrochemiluminescent single gold microbeads

Fast and high-throughput determination of drugs is a key trend in clinical medicine. Single particles have increasingly been adopted in a variety of photoanalytical and electroanalytical applications, and microscopic analysis has been a hot topic in recent years, especially for electrochemiluminescence (ECL). This paper describes a simple ECL method based on single gold microbeads to image lecithin. Lecithin reacts to produce hydrogen peroxide under the successive enzymatic reaction of phospholipase D and choline oxidase. ECL was generated by the electrochemical reaction between a luminol analog and hydrogen peroxide, and ECL signals were imaged by a camera. Despite the heterogeneity of single gold microbeads, their luminescence obeyed statistical regularity. The average luminescence of 30 gold microbeads is correlated with the lecithin concentration, and thus, a visualization method for analyzing lecithin was established. Calibration curves were constructed for ECL intensity and lecithin concentration, achieving detection limits of 0.05 mM lecithin. This ECL imaging platform based on single gold microbeads exhibits outstanding advantages, such as high throughput, versatility and low cost, and holds great potential in disease diagnostics, environmental monitoring and food safety.

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The ECL imaging strategy reflected the advantage of spatial resolution and high-throughput analysis of lecithin in drugs.

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Micrometer-scale gold microbeads were easily synthesized by adding H₂SO₄ in Na₃Au(SO₃)₂ solution.

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The ECL spots exhibited the heterogeneity of single gold microbeads in ECL reaction.

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ECL microscopic quantitative analysis for lecithin was established via single gold microbeads with PLD and COD.