400
Z. Wang and B. Luk’yanchuk
probe [119]; the generated PNJ focus was used for real-time manipulation (trapping
and releasing) and detection of 85 nm objects like nanoparticles and biomolecules,
as shown in Fig. 15.20d, e. A multifunctional Lab-on-Chip (LoC) device capable of
delivering real-time trapping, detection and super-resolution imaging functionalities
was recently proposed and partially experimentally demonstrated by Yan et al., where
a coverslip-style microsphere superlens was bonded onto a microfluidic chip on silicon. The trapping function was realized by dielectrophoretic (may also with PNJ
effect). When bio-samples flowing through the channel, the objects will be trapped
by the dielectrophoretic force at locations beneath the particles, super-resolution
images were then obtained through microsphere imaging. The successful realization
of proposed device may lead to fundamental changes to biomedical analysis with
accuracy in nanometre scales.
15.7 Outlook and Conclusions
Compared to other super-resolution techniques, the microsphere nanoscopy technique has several distinct features—simple, easy to implement, label-free, highresolution and compatible with conventional white-lighting imaging. The scanning
superlens system has generated possible opportunities for commercialization, a few
start-up companies were recently setup using first-generation dielectric superlenses
(PS or BTG particles) technology. These systems are likely to suffer from low imaging contrast and quality compared to second-generation particle superlenses based
on metamaterials. Development of commercially viable prototype of metamaterial
dielectric superlens is of considerable interests in the next-step development of the
technique.
For microsphere imaging, one possible way to further improve the system resolution is to use microfiber to evanescently illustrate the specimen [120]. Imaging
contrast in this case can be greatly improved owing to the limited illumination depth
(typical < 200 nm) of the evanescent waves; sharp and clear images of nanostructures
have been achieved [120]. This idea may worth further exploration for sub-50 nm
resolution imaging in the future, by extending the evanescence wave illumination
approach to microspheres; either prism-style or objective-style TIRM (Total Internal
Reflection microscopy) setup can be used [121].
On application side, the breakthrough is likely to come from in vivo endoscopy
application where other super-resolution techniques (STED) cannot be applied. The
super-resolution endoscope can provide real-time high-resolution image of internal
cells and tissues for the early diagnostics of cancers and other diseases.
On the other hand, studies on new effects generated by particles are emerging
and growing, including nanoparticle super-resolution, microsphere super-resonance,
microsphere array Talbot effect [122], and micro-prism ‘photonic hook’ [123], etc.
The ‘photonic hook’ effect may be used for nanoscale light switching and guiding
in a Photonic Integrated Chip. The factual Talbot effect of a microsphere lens array
may be used to develop a far-field particle-lens super-resolution imaging system.
Z. Wang and B. Luk’yanchuk
probe [119]; the generated PNJ focus was used for real-time manipulation (trapping
and releasing) and detection of 85 nm objects like nanoparticles and biomolecules,
as shown in Fig. 15.20d, e. A multifunctional Lab-on-Chip (LoC) device capable of
delivering real-time trapping, detection and super-resolution imaging functionalities
was recently proposed and partially experimentally demonstrated by Yan et al., where
a coverslip-style microsphere superlens was bonded onto a microfluidic chip on silicon. The trapping function was realized by dielectrophoretic (may also with PNJ
effect). When bio-samples flowing through the channel, the objects will be trapped
by the dielectrophoretic force at locations beneath the particles, super-resolution
images were then obtained through microsphere imaging. The successful realization
of proposed device may lead to fundamental changes to biomedical analysis with
accuracy in nanometre scales.
15.7 Outlook and Conclusions
Compared to other super-resolution techniques, the microsphere nanoscopy technique has several distinct features—simple, easy to implement, label-free, highresolution and compatible with conventional white-lighting imaging. The scanning
superlens system has generated possible opportunities for commercialization, a few
start-up companies were recently setup using first-generation dielectric superlenses
(PS or BTG particles) technology. These systems are likely to suffer from low imaging contrast and quality compared to second-generation particle superlenses based
on metamaterials. Development of commercially viable prototype of metamaterial
dielectric superlens is of considerable interests in the next-step development of the
technique.
For microsphere imaging, one possible way to further improve the system resolution is to use microfiber to evanescently illustrate the specimen [120]. Imaging
contrast in this case can be greatly improved owing to the limited illumination depth
(typical < 200 nm) of the evanescent waves; sharp and clear images of nanostructures
have been achieved [120]. This idea may worth further exploration for sub-50 nm
resolution imaging in the future, by extending the evanescence wave illumination
approach to microspheres; either prism-style or objective-style TIRM (Total Internal
Reflection microscopy) setup can be used [121].
On application side, the breakthrough is likely to come from in vivo endoscopy
application where other super-resolution techniques (STED) cannot be applied. The
super-resolution endoscope can provide real-time high-resolution image of internal
cells and tissues for the early diagnostics of cancers and other diseases.
On the other hand, studies on new effects generated by particles are emerging
and growing, including nanoparticle super-resolution, microsphere super-resonance,
microsphere array Talbot effect [122], and micro-prism ‘photonic hook’ [123], etc.
The ‘photonic hook’ effect may be used for nanoscale light switching and guiding
in a Photonic Integrated Chip. The factual Talbot effect of a microsphere lens array
may be used to develop a far-field particle-lens super-resolution imaging system.