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Surface modified hexagonal upconversion nanoparticles for the development of competitive assay for biodetection.
Padmaja Parameswaran Nampi1, Alexander Vakurov2, Sikha Saha3
1School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom.
Researchers developed up-conversion nanoparticles (UCNPs) for detecting the antibiotic ofloxacin. These modified nanoparticles form the basis of a sensitive and rapid photoluminescent nanobiosensor.
Area of Science:
- Materials Science
- Nanotechnology
- Analytical Chemistry
Background:
- Up-conversion nanoparticles (UCNPs) offer unique optical properties for sensing applications.
- Sodium yttrium fluoride UCNPs doped with ytterbium (Yb3+) and erbium (Er3+) ions exhibit strong green luminescence.
- Surface modification is crucial for integrating UCNPs into biosensing platforms.
Purpose of the Study:
- To synthesize and characterize uniform β-NaYF4/Yb3+/Er3+ UCNPs.
- To develop a stable, aqueous-compatible UCNP platform for biomolecule detection.
- To create a photoluminescent nanobiosensor for the detection and quantification of ofloxacin.
Main Methods:
- Solvothermal synthesis of β-NaYF4/Yb3+/Er3+ UCNPs with controlled size and hexagonal phase.
- Silica coating to enhance aqueous stability.
- Surface functionalization with maleimide-polyethylene glycol-silane (mal-PEG-silane) for antibody conjugation.
- Competitive immunoassay utilizing antibody-conjugated UCNPs for ofloxacin detection.
Main Results:
- Uniform ~50 nm hexagonal UCNPs with strong green up-conversion luminescence were synthesized.
- Silica coating rendered the UCNPs stable in aqueous media.
- Maleimide-functionalized UCNPs were successfully conjugated to antibodies.
- A sensitive competitive assay detected ofloxacin down to ~10 nM.
Conclusions:
- The developed UCNP-based nanobiosensor is effective for detecting ofloxacin.
- The assay demonstrates high sensitivity and speed, suitable for veterinary antibiotic monitoring.
- This platform holds promise for developing sensors for various biomolecules.
