Manipulation and detection of single nanoparticles and biomolecules by a photonic nanojet

Abstract

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 ∼103 and ∼30, respectively. The demonstrated approach provides a potentially powerful tool for nanostructure assembly, biosensing and single-biomolecule studies.

A Photonic Nanojet as Tunable and Polarization‐Sensitive Optical Tweezers

“…High efficiency of PNJs for nano‐object trapping was also confirmed experimentally . In these cases, dielectric microspheres attached to a microscope probe produced photonic PNJs to trap and manipulate biological objects, such as blood cells or DNA.…”

Optical Trapping and Manipulation Using Optical Fibers

“…In addition to super-resolution optical microscopy [79], photonic nanojet also finds application in optical trapping for forming a high gradient force. A simple photonic nanojet trapping system contains a tapered optical fiber tip and a dielectric polystyrene (PS) microsphere attached on the tip [80] (Fig. 4c).…”

Surface chemistry modified upconversion nanoparticles as fluorescent sensor array for discrimination of foodborne pathogenic bacteria

“…However, the traditional bacterial species identification methods heavily rely on time-consuming and low-accuracy phenotypic characterizations such as serotype by Gram staining and biochemical methods [4]. Polymerase chain reaction (PCR), gene sequencing, surface enhanced Raman scattering (SERS), and mass spectrometry as well as a series of specificity sensing methods for analysis bacteria based on the affinity reagents (including peptide, phage, antibiotic, antibody, and aptamer) have been widely employed to precise traceability analysis [8][9][10][11][12][13], the main limitations of these methods are highly reliant on expensive reagents, sophisticated costly and bulky equipment, elusive manipulations, and trained personnel and handling conditions [7,13]. Furthermore, to ensure effective treatments, timely and reliable diagnosis of pathogen infection is the primary step [14].…”