Microneedle-based ocular drug delivery systems – recent advances and challenges

• Piotr Gadziński,
• Anna Froelich,
• Monika Wojtyłko,
• Antoni Białek,
• Julia Krysztofiak and
• Tomasz Osmałek

Beilstein J. Nanotechnol. 2022, 13, 1167–1184, doi:10.3762/bjnano.13.98

• such as blinking and nasolacrimal drainage, anatomical barriers, efflux pumps, and metabolism in ocular tissues are responsible for drug elimination [38]. It is noteworthy that the tear film is completely replaced with a new one by the tear fluid secreted at a rate of 1.2 mL/min. The eye is also

Nanogenerator-based self-powered sensors for data collection

• Yicheng Shao,
• Maoliang Shen,
• Yuankai Zhou,
• Xin Cui,
• Lijie Li and
• Yan Zhang

Beilstein J. Nanotechnol. 2021, 12, 680–693, doi:10.3762/bjnano.12.54

• pressure sensor that can detect situations such as the driver stepping on the accelerator or blinking. In 2020, Lu et al. [11] further proposed a transparent stretchable self-powered sensor based on a polyacrylamide TENG (PL-TENG), which is used to detect driver fatigue and distraction while driving and

Toward graphene textiles in wearable eye tracking systems for human–machine interaction

• Ata Jedari Golparvar and
• Murat Kaya Yapici

Beilstein J. Nanotechnol. 2021, 12, 180–189, doi:10.3762/bjnano.12.14

• contrast, slow eye movements control the cursor motion in vertical directions. Finally, voluntary blinking mimics the mouse click action. When swift or slow eye movements occur, the cursor starts to move in the defined direction at a preconfigured speed until it reaches the edge of the display or until a

• movements (EMs) allow one to steer the robot in different directions as follows: (i) swift left EM or blinking trigger forward motion (↑), (ii) swift right EM triggers backward motion (↓), (iii) slow left EM triggers rotation to the left (←), (iv) slow right EM triggers rotation to the right (→). Insets

Paper-based triboelectric nanogenerators and their applications: a review

• Jing Han,
• Nuo Xu,
• Yuchen Liang,
• Mei Ding,
• Junyi Zhai,
• Qijun Sun and
• Zhong Lin Wang

Beilstein J. Nanotechnol. 2021, 12, 151–171, doi:10.3762/bjnano.12.12

• design and to be low cost and lightweight. TENGs have also shown the pivotal ability to convert low-frequency mechanical energy from walking, waving, and eye-blinking into electricity. TENGs can readily serve as a sustainable power supply based on four basic operation modes [29], including vertical

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• criteria to benchmark the performance of a solid-state SPS to be considered suitable for applications in quantum technology [7][8][80]. These include the following: photo-stable emission without blinking or photo-bleaching; narrow bandwidth with most of the emission in the zero phonon line (ZPL), which is

• energy in each group (±20 meV) was attributed to variations of the strain in the h-BN matrix, as well as photo-conversion to a dark state that may be responsible for the blinking. Only 5% of the emitters were photostable. The photo-dynamics indicates the presence of a metastable state (3-level system

• at 675 nm, and emitters with ZPLs of 760 nm were found with a much shorter lifetime and a saturation count rate in the 200 kcts/s. The photo-dynamics of these emitters indicate the presence of a multilevel system with three metastable states with long decay rates of 480 ns, 5 µs and 31 ms. Blinking

Small protein sequences can induce cellular uptake of complex nanohybrids

• Jan-Philip Merkl,
• Malak Safi,
• Christian Schmidtke,
• Fadi Aldeek,
• Johannes Ostermann,
• Tatiana Domitrovic,
• Sebastian Gärtner,
• John E. Johnson,
• Horst Weller and
• Hedi Mattoussi

Beilstein J. Nanotechnol. 2019, 10, 2477–2482, doi:10.3762/bjnano.10.238

• for the staining of cell membranes [4]. In two separate studies, Chan and co-workers described two interesting hybrid systems. In the first, a charge driven self-assembly of AuNPs and different-colour QDs into multicolour, non-blinking nanohybrids was introduced. These nanohybrids were then coupled to

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

• ultrashort 10 ms acquisition times in sub-nanomolar amounts of Gd spins. The photobleaching and blinking issues of NV are addressed in [27] by use of fluorescent ND (FND), which has an extremely high NV center concentration. Their lifetimes are longer than fluorescent biomolecules, and the emission can be

• -manipulated nanoscopy has been set up for nanoscale resolution imaging of collectively blinking NV centers when they are confined within the diffraction-limited region [61]. Collective spontaneous emission in nanomaterials is a common feature and relates to fundamental photophysical properties. Multiple NV

• emission in 45 nm or less is often subject to collective emission. Using wide-field localization microscopy combined with nanoscale spin manipulation based on a microwave source tuned to the ODMR frequency, two collectively blinking NV centers could be resolved within the diffraction limit. Here

Correlation of surface-enhanced Raman scattering (SERS) with the surface density of gold nanoparticles: evaluation of the critical number of SERS tags for a detectable signal

• Vincenzo Amendola

Beilstein J. Nanotechnol. 2019, 10, 1016–1023, doi:10.3762/bjnano.10.102

• the absence of blinking or bleaching, and the possibility to excite in the red or near infrared spectral range, where most matrixes and substrates have low fluorescence background [13][17]. Therefore, due to the increasing demand for ultrasensitive identification and quantification of specific

Room-temperature single-photon emitters in titanium dioxide optical defects

• Kelvin Chung,
• Yu H. Leung,
• Chap H. To,
• Aleksandra B. Djurišić and
• Snjezana Tomljenovic-Hanic

Beilstein J. Nanotechnol. 2018, 9, 1085–1094, doi:10.3762/bjnano.9.100

• thin films and commercial nanoparticles. Three-level defects were identified because the g(2) correlation data featured prominent shoulders around the antibunching dip. Stable and blinking photodynamics were observed for the single-photon emitters. These results reveal a new room-temperature single

• with no obvious fluorescence intermittency, i.e., blinking. Subsequent measurements of D1 could not be conducted beyond 118 μW due to the defect photobleaching. This was confirmed by re-scanning the area of interest during which the original bright spot on the confocal image, indicative of a

• histogram observed for D2 at 99.0 ± 0.5 μW pump power exhibiting relative photostability. When the power is increased to 148.0 ± 0.5 μW, the defect exhibits blinking between two distinct levels of an “off” and an “on” state, i.e., a ground state and a bright state, which can be seen in Figure 5d. D2 showed

Photobleaching of YOYO-1 in super-resolution single DNA fluorescence imaging

• Joseph R. Pyle and
• Jixin Chen

Beilstein J. Nanotechnol. 2017, 8, 2296–2306, doi:10.3762/bjnano.8.229

• spread function (PSF) by fitting it to, for example, a Gaussian function (Figure 1). Then all the frames are overlaid to construct the super-resolved image. The difference between each technique is how the single molecules are visualized, typically through blinking, photobleaching, binding activation

• density under our experimental conditions (Figure 6). Lower laser power densities can be used with the help of data analysis methods that tolerate a higher active-dye density and slight overlap of the PSFs, such as SHRIMP [34][54], Bayesian analysis of the blinking and bleaching (3B) [37][55], compressed

Evaluation of quantum dot conjugated antibodies for immunofluorescent labelling of cellular targets

• Jennifer E. Francis,
• David Mason and
• Raphaël Lévy

Beilstein J. Nanotechnol. 2017, 8, 1238–1249, doi:10.3762/bjnano.8.125

• spectra and smaller Qdots in the blue region [1]. Qdots are also an ideal probe choice for super-resolution imaging techniques that require stochastic optical fluctuation, as they exhibit well-characterised blinking between fluorescent and non-fluorescent states [10][11]. Despite these favourable

Single-molecule mechanics of protein-labelled DNA handles

• Vivek S. Jadhav,
• Dorothea Brüggemann,
• Florian Wruck and
• Martin Hegner

Beilstein J. Nanotechnol. 2016, 7, 138–148, doi:10.3762/bjnano.7.16

• out of focus or the known blinking of fluorescing quantum dots [32] (Figure 8). This single molecule fluorescence experiment clearly visualizes the specific binding of a protein to the biotinylated end of the dsDNA. Since the dsDNA was not labelled with intercalating dyes in this fluorescence

Probing the local environment of a single OPE3 molecule using inelastic tunneling electron spectroscopy

• Riccardo Frisenda,
• Mickael L. Perrin and
• Herre S. J. van der Zant

Beilstein J. Nanotechnol. 2015, 6, 2477–2484, doi:10.3762/bjnano.6.257

• local environment. A similar conclusion has been drawn by Ward et al. for the Raman response of single-molecule junctions [27], in which spectral diffusion and blinking were reported. To relate the peaks in the IETS spectra to the vibrational modes, we used the Amsterdam Density Functional (ADF) package

Conductance through single biphenyl molecules: symmetric and asymmetric coupling to electrodes

• Karthiga Kanthasamy and
• Herbert Pfnür

Beilstein J. Nanotechnol. 2015, 6, 1690–1697, doi:10.3762/bjnano.6.171

• to changes in bonding sites of the molecule on the electrodes, which have a great impact on conductance. The pronounced switching in conductance at times between 36–46 h has been characterized earlier as blinking of the thiol–gold bond, a characteristic of any molecule bonded to gold surface via

Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

• Jes Ærøe Hyllested,
• Marta Espina Palanco,
• Nicolai Hagen,
• Klaus Bo Mogensen and
• Katrin Kneipp

Beilstein J. Nanotechnol. 2015, 6, 293–299, doi:10.3762/bjnano.6.27

• luminescent light shows strong fluctuations (see movie in Supporting Information File 1). These blinking hints to surface-enhanced emission of individual single emitters made from small silver clusters on the surface of plasmonic silver nanoparticles. Conclusion Silver nanoparticles can be prepared in a

Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• differences are clearly outside of the error margins for cysteamine- and DPA-coated QDs. QDs are exceptionally bright and show intermittent emission (“blinking”), and one must take great care to avoid optical saturation, which results in an overestimation of the actual size [47][48]. HSA binding to QDs with

Photoactivation of luminescence in CdS nanocrystals

• Valentyn Smyntyna,
• Bogdan Semenenko,
• Valentyna Skobeeva and
• Nikolay Malushin

Beilstein J. Nanotechnol. 2014, 5, 355–359, doi:10.3762/bjnano.5.40

• fluorescence enhancement (PFE) [1][2][3][4][5], intermittency or blinking of photoluminescence [6][7][8], and a blue- or red-shift of the exciton PL of nanocrystals [5][9]. Despite the large number of works devoted to the surface interactions in II–IV QDs [2][3][4][5][10] the mechanisms responsible for the

A nano-graphite cold cathode for an energy-efficient cathodoluminescent light source

• Alexander N. Obraztsov,
• Victor I. Kleshch and
• Elena A. Smolnikova

Beilstein J. Nanotechnol. 2013, 4, 493–500, doi:10.3762/bjnano.4.58

• estimation. However, the observed emission was very unstable in time with blinking and moving spots in the FE image and with a variation of the FE current. The averaged total value of the field emission current at constant applied voltage significantly decreased with time within a few minutes. Black traces

Combining nanoscale manipulation with macroscale relocation of single quantum dots

• Francesca Paola Quacquarelli,
• Richard A. J. Woolley,
• Martin Humphry,
• Jasbiner Chauhan,
• Philip J. Moriarty and
• Ashley Cadby

Beilstein J. Nanotechnol. 2012, 3, 324–328, doi:10.3762/bjnano.3.36

• [13]. The gold nanoparticle was shown to dramatically quench the optical lifetime of the QD and to completely suppress its blinking. Experimental In this work, we position a single fluorophore, a CdSe QD, with nanometre precision on a macroscopic registration template, using automated atomic force

• manipulated QD is centred at 608 nm, and luminescence at this wavelength is completely absent elsewhere in the cell. The full-width at half-maximum (FWHM) of the QD spectra is 108 meV, which corresponds well to the previously studied emission from single colloidal quantum dots, for which PL blinking was

• recorded to optically identify the emission as being that from a single QD [20][21]. Due to limitations in the collection optics it was not possible to see blinking in our sample. The PL contamination, caused by chromium defects in the sapphire, limits the use of this substrate to QDs with peak emission

Distance dependence of near-field fluorescence enhancement and quenching of single quantum dots

• Volker Walhorn,
• Jan Paskarbeit,
• Heinrich Gotthard Frey,
• Alexander Harder and
• Dario Anselmetti

Beilstein J. Nanotechnol. 2011, 2, 645–652, doi:10.3762/bjnano.2.68

• suffer from the typical intermittent fluorescence emission of quantum dots, often referred to as blinking, but the effect on the results was reduced by binning three distance steps together. The integrated fluorescence intensity shows a pronounced distance dependence for gap sizes below 75 nm (Figure 2

Room temperature excitation spectroscopy of single quantum dots

• Christian Blum,
• Frank Schleifenbaum,
• Martijn Stopel,
• Sébastien Peter,
• Marcus Sackrow,
• Vinod Subramaniam and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2011, 2, 516–524, doi:10.3762/bjnano.2.56

• . Keywords: blinking; excitation spectrum; quantum dots; single molecule spectroscopy; supercontinuum laser; Introduction Since the first demonstration of single molecule fluorescence spectroscopy over two decades ago, techniques to detect and characterize the emission from single emitters have become

• recorded excitation spectra of 48 individual CdSe/ZnS core–shell quantum dots at room temperature. Since the occurrence of emission intermittencies (blinking) is a clear indication for the observation of a single emitter, and because blinking of quantum dots is still not fully understood, we did not apply

• any measures to suppress or minimize blinking. The single quantum dot excitation spectra recorded exhibited the main characteristics of a declining slope from shorter to longer wavelengths, and a peak close to the band edge transition, which we identify as the 1S(e)-2S3/2(h) transition [39]. However