Manipulation and detection of single nanoparticles and biomolecules by a photonic nanojet
Optical methods to manipulate and detect nanoscale objects are highly desired in both nanomaterials and molecular biology fields. Optical tweezers have been used to manipulate objects that range in size from a few hundred nanometres to several micrometres. The emergence of near-field methods that ov...
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Veröffentlicht in: | Light, science & applications science & applications, 2016-12, Vol.5 (12), p.e16176-e16176 |
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Zusammenfassung: | Optical methods to manipulate and detect nanoscale objects are highly desired in both nanomaterials and molecular biology fields. Optical tweezers have been used to manipulate objects that range in size from a few hundred nanometres to several micrometres. The emergence of near-field methods that overcome the diffraction limit has enabled the manipulation of objects below 100 nm. A highly free manipulation with signal-enhanced real-time detection, however, remains a challenge for single sub-100-nm nanoparticles or biomolecules. Here we show an approach that uses a photonic nanojet to perform the manipulation and detection of single sub-100-nm objects. With the photonic nanojet generated by a dielectric microlens bound to an optical fibre probe, three-dimensional manipulations were achieved for a single 85-nm fluorescent polystyrene nanoparticle as well as for a plasmid DNA molecule. Backscattering and fluorescent signals were detected with the enhancement factors up to ∼10
3
and ∼30, respectively. The demonstrated approach provides a potentially powerful tool for nanostructure assembly, biosensing and single-biomolecule studies.
Optical manipulation: moving single nanoparticles and biomolecules
By using photonic nanojets, a team in China has succeeded in simultaneously manipulating and detecting single nanoparticles and biomolecules. Optical tweezers are well known for their ability to manipulate small objects down to several hundred nanometres, but optical manipulation techniques capable of shifting even smaller objects are highly desired. Now, Baojun Li at Jinan University in Guangzhou and co-workers have used tiny light beams known as photonic nanojets to move a 85-nm polystyrene nanoparticle and a plasmid DNA molecule. Their technique can also simultaneously detect the particles due to the large signal enhancement generated by the nanojets. The nanojets were obtained from the near-field generated by a spherical polystyrene microlens attached to an optical fibre. Unlike other near-field techniques, this one does not require complex nanofabrication processes or bulky optical elements. |
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ISSN: | 2047-7538 2095-5545 2047-7538 |
DOI: | 10.1038/lsa.2016.176 |