Recyclable metal nanoparticle-immobilized polymer dot on montmorillonite for alkaline phosphatase-based colorimetric sensor with photothermal ablation of Bacteria

• Published in: Analytica chimica acta Vol. 1082; pp. 152 - 164
• Main Authors: Robby, Akhmad Irhas, Park, Sung Young
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2019
• Subjects: Alkaline phosphatase; Alkaline Phosphatase - chemistry; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Bentonite - chemistry; beta-Cyclodextrins - chemistry; Cesium - chemistry; Cesium - radiation effects; Cesium tungsten oxide; Colorimetric detection; Colorimetry - instrumentation; Colorimetry - methods; Equipment Reuse; Escherichia coli - drug effects; Escherichia coli - isolation & purification; Heating; Infrared Rays; Iron oxide; Limit of Detection; Magnetite Nanoparticles - chemistry; Magnetite Nanoparticles - radiation effects; Microbial Sensitivity Tests - instrumentation; Microbial Sensitivity Tests - methods; Montmorillonite; Nanocomposites - chemistry; Nitrophenols - chemistry; Organophosphorus Compounds - chemistry; Polymer dot; Polymers - chemistry; Quantum Dots - chemistry; Staphylococcus aureus - drug effects; Staphylococcus aureus - isolation & purification; Tungsten Compounds - chemistry; Tungsten Compounds - radiation effects; Alkaline phosphatase; Polymer dot; Iron oxide; Montmorillonite; Cesium tungsten oxide; Colorimetric detection
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2019.07.053

Development of simultaneous bacteria detection and eradication with simple, rapid, and reusable material is important in addressing bacterial contamination issues. In this study, we utilized the expression of alkaline phosphatase (ALP) from bacteria to design fluorescence ON/OFF system for bacteria detection, also using metal oxide nanoparticle for obtaining antibacterial activity and recyclability. The fluorescent-based biosensor with antibacterial activity was prepared by intercalating ALP-sensitive polymer dot (PD) containing β-cyclodextrin (β-CD) onto montmorillonite (MMT) as loading matrix via ionic exchange reaction, followed by immobilization of magnetic iron oxide (Fe3O4) and NIR-responsive cesium tungsten oxide (CsWO3). The PD-βCD-MMT/Fe3O4–CsWO3 nanocomposite exhibited strong fluorescence intensity, which was quenched in the presence of bacterial ALP (0–1000 U/L) due to hydrolysis of p-nitrophenyl phosphate (NPP) into p-nitrophenol (NP) in the hydrophobic site of β-CD. Furthermore, the nanocomposite could detect both gram-negative Escherichia coli and gram-positive Staphylococcus aureus in the range of 101–107 CFU/mL (LOD 5.09 and 4.62 CFU/mL, respectively), and showed high antibacterial activity against bacteria by generating photothermal heat under 5 min NIR irradiation, causing damage to bacterial cells. This material also demonstrated recyclability via magnetic field exposure due to the presence of Fe3O4. In addition, the fluorescence can be recovered following pH shock and re-conjugation of β-CD molecules. After 4 cycles, nanocomposite still showed stable photothermal effects and fluorescence-based bacteria detection. Thus, this reusable material offers promising approach for simultaneous bacteria detection and killing, which is simple, rapid, and effective. [Display omitted] •Reusable material was designed for fluorometric sensing and photothermolysis of bacteria.•The fluorescence ON/OFF sensing system was depended on the bacterial ALP activity.•The LOD of fluorescence-based bacteria detection showed below 101 CFU/mL.•Hybrid nanocomposite showed ±100% killing efficiency after 5 min NIR irradiation.•Antibacterial/bacteria sensing showed excellent performance even after 4 cycles.