Ligand Equilibrium Influences Photoluminescence Blinking in CsPbBr3: A Change Point Analysis of Widefield Imaging Data.

Photoluminescence intermittency remains one of the biggest challenges in realizing perovskite quantum dots (QDs) as scalable single photon emitters. We compare CsPbBr3 QDs capped with different ligands, lecithin, and a combination of oleic acid and oleylamine, to elucidate the role of surface chemistry on photoluminescence intermittency. We employ widefield photoluminescence microscopy to sample the blinking behavior of hundreds of QDs. Using change point analysis, we achieve the robust classification of blinking trajectories, and we analyze representative distributions from large numbers of QDs (Nlecithin = 1308, Noleic acid/oleylamine = 1317). We find that lecithin suppresses blinking in CsPbBr3 QDs compared with oleic acid/oleylamine. Under common experimental conditions, lecithin-capped QDs are 7.5 times more likely to be nonblinking and spend 2.5 times longer in their most emissive state, despite both QDs having nearly identical solution photoluminescence quantum yields. We measure photoluminescence as a function of dilution and show that the differences between lecithin and oleic acid/oleylamine capping emerge at low concentrations during preparation for single particle experiments. From experiment and first-principles calculations, we attribute the differences in lecithin and oleic acid/oleylamine performance to differences in their ligand binding equilibria. Consistent with our experimental data, density functional theory calculations suggest a stronger binding affinity of lecithin to the QD surface compared to oleic acid/oleylamine, implying a reduced likelihood of ligand desorption during dilution. These results suggest that using more tightly binding ligands is a necessity for surface passivation and, consequently, blinking reduction in perovskite QDs used for single particle and quantum light experiments.

Rapid Voluntary Blinking as a Clinical Marker of Parkinson's Disease.

Reduced spontaneous blinking is a recognized Parkinson's disease (PD) feature. In contrast, voluntary blinking has been less studied and might serve as a measurable marker of facial bradykinesia. We tested 31 PD patients and 31 controls. Participants were filmed during conversation and a rapid blinking task. Both tasks were videorecorded to count the number of blinks per second. PD patients had lower blink rates. Rapid blinking accurately discriminated between groups with 77% sensitivity and 71% specificity. To conclude, rapid blinking may be a simple and quantifiable task of facial bradykinesia.

Decreased blinking without conscious effort is a well-known characteristic of Parkinson's disease (PD). However, voluntary blinking, which is blinking on purpose, has not been studied as much and could be a sign of slower facial movements. We studied a group of people with PD and another one without the disease. We recorded videos of them talking and doing a task where they blinked quickly. Then, we counted how many times they blinked per second in each video. We found that people with PD blinked less often. The rapid blinking task accurately distinguished between those with PD and those without it, being correct about 77% of the time for spotting PD and 71% for spotting non-PD. In conclusion, the rapid blinking task could be a simple and measurable way to identify slower facial movements in PD.

Photo-uncaging Triggers on Self-Blinking to Control Single-Molecule Fluorescence Kinetics for Super-resolution Imaging.

Super-resolution imaging, especially a single-molecule localization approach, has raised a fluorophore engineering revolution chasing sparse single-molecule dark-bright blinking transforms. Yet, it is a challenge to structurally devise fluorophores manipulating the single-molecule blinking kinetics. In this pursuit, we have developed a triggering strategy by innovatively integrating the photoactivatable nitroso-caging strategy into self-blinking sulfonamide to form a nitroso-caged sulfonamide rhodamine (NOSR). Our fluorophore demonstrated controllable self-blinking events upon phototriggered caging unit release. This exceptional blink kinetics improved the super-resolution imaging integrity on microtubules compared to self-blinking analogues. With the aid of paramount single-molecule fluorescence kinetics, we successfully reconstructed the ring structure of nuclear pores and the axial morphology of mitochondrial outer membranes. We foresee that our synthetic approach of photoactivation and self-blinking would facilitate rhodamine devising for super-resolution imaging.

Enhanced fluorescence blinking of AF647 fluorophores in Mowiol via violet and UV light induced recovery for superior localization microscopy.

Blinking of fluorophores is essential in the context of single molecule localization-based optical super-resolution microscopy methods. To make the fluorescence molecule undergo blinking specific complex chemical mounting buffer systems, combined with suitable oxygen scavengers, and reducing agents are required. For instance to realise blinking in widely used fluorescence tags, like Alexa Fluor 647 (AF647), they are to be mounted on anti-fading buffer such as Mowiol and reducing agent such as Beta (ß) - ME. However, the quality of the super-resolved images is decided by the total number of blinking events or in other words net duration for which the fluorescence blinking persists. In this paper we investigate how a violet and UV light induced fluorescence recovery mechanism can enhance the duration of fluorescence blinking. Our study uses AF647 dye conjugated with Phalloidin antibody in U87MG cell line mounted on Mowiol andß- ME. On the basis of the investigation we optimize the intensity, at the sample plane, of fluorescence excitation laser at 638 nm and fluorescence recovery beam at 405 nm or in the UV giving the maximum possible fluorescence blinking duration. We observe that the longer blinking duration, using the optimized illumination scheme, has brought down the resolution in the super-resolved image, as given by Fourier Ring Correlation method, from 168 nm to 112 nm, while the separation between two nearby resolvable filaments has been brought down to ≤ 60 nm.

Weakly Confined Organic-Inorganic Halide Perovskite Quantum Dots as High-Purity Room-Temperature Single Photon Sources.

Colloidal perovskite quantum dots (PQDs) have emerged as highly promising single photon emitters for quantum information applications. Presently, most strategies have focused on leveraging quantum confinement to increase the nonradiative Auger recombination (AR) rate to enhance single-photon (SP) purity in all-inorganic CsPbBr3 QDs. However, this also increases the fluorescence intermittency. Achieving high SP purity and blinking mitigation simultaneously remains a significant challenge. Here, we transcend this limitation with room-temperature synthesized weakly confined hybrid organic-inorganic perovskite (HOIP) QDs. Superior single photon purity with a low g(2)(0) < 0.07 ± 0.03 and a nearly blinking-free behavior (ON-state fraction >95%) in 11 nm FAPbBr3 QDs are achieved at room temperature, attributed to their long exciton lifetimes (τX) and short biexciton lifetimes (τXX). The significance of the organic A-cation is further validated using the mixed-cation FAxCs1-xPbBr3. Theoretical calculations utilizing a combination of the Bethe-Salpeter (BSE) and k·p approaches point toward the modulation of the dielectric constants by the organic cations. Importantly, our findings provide valuable insights into an additional lever for engineering facile-synthesized room-temperature PQD single photon sources.

Squaraine Dyes Exhibit Spontaneous Fluorescence Blinking That Enables Live-Cell Nanoscopy.

Hampered by their susceptibility to nucleophilic attack and chemical bleaching, electron-deficient squaraine dyes have long been considered unsuitable for biological imaging. This study unveils a surprising twist: in aqueous environments, bleaching is not irreversible but rather a reversible spontaneous quenching process. Leveraging this new discovery, we introduce a novel deep-red squaraine probe tailored for live-cell super-resolution imaging. This probe enables single-molecule localization microscopy (SMLM) under physiological conditions without harmful additives or intense lasers and exhibits spontaneous blinking orchestrated by biological nucleophiles, such as glutathione or hydroxide anion. With a low duty cycle (∼0.1%) and high-emission rate (∼6 × 104 photons/s under 400 W/cm2), the squaraine probe surpasses the benchmark Cy5 dye by 4-fold and Si-rhodamine by a factor of 1.7 times. Live-cell SMLM with the probe reveals intricate structural details of cell membranes, which demonstrates the high potential of squaraine dyes for next-generation super-resolution imaging.

A Novel Ex Vivo Blinking Method for Comparing the Corneal Residence Time of New Shampoo Formulations.

In the cosmetics sector, many products such as shampoos have a probability of accidental ocular exposure during their routine use. One very specific safety parameter is the residence time of the substance on the corneal surface, as prolonged exposure may cause injury. In this study, we developed a system that simulates corneal exposure to blinking and tear flow, for comparing the corneal clearance times of viscous detergent formulations. The Ex Vivo Eye Irritation Test (EVEIT), which uses corneal explants from discarded rabbit eyes from an abattoir, was used as the basis for the new system. To simulate blinking, we developed a silicone wiping membrane to regularly move across the corneal surface, under conditions of constant addition and aspiration of fluid, to mimic tear flow. Six shampoo formulations were tested and were shown to differ widely in their corneal clearance time. Three groups could be identified according to the observed clearance times (fast, intermediate and slow); the reference shampoo had the shortest clearance time of all tested formulations. With this new system, it is now possible to investigate an important physicochemical parameter, i.e. corneal clearance time, for the consideration of ocular safety during the development of novel cosmetic formulations.

Simultaneous Recording of Remote Domain Dynamics in Membrane Proteins Using the Double-Labeled DXB/DXT Technique.

Protein dynamics play important roles in biological functions, which accompany allosteric structure changes. Diffracted X-ray blinking (DXB) uses monochromatic X-rays and nanocrystal probes. The intramolecular motion of target proteins is analyzed from the intensity changes in detector signals at the diffraction rings. In contrast, diffracted X-ray tracking (DXT) elucidates molecular dynamics by analyzing the trajectories of Laue spots. In this study, we have developed a dual-labeling technique for DXB and DXT, allowing the simultaneous observation of motions at different domains in proteins. We identified zinc oxide (ZnO) crystals as promising candidates for the second labeling probes due to their excellent diffraction patterns, high chemical stability, and favorable binding properties with proteins. The diffraction spots from the ZnO crystals are sufficiently separated from those of gold, enabling independent motion analysis at different domains. Dual-labeling DXB was employed for the motion analysis of the 5-HT2A receptor in living cells. Simultaneous motion recording of the N-terminus and the second extracellular loop demonstrated ligand-induced motion suppression at both domains. The dual-labeling DXT technique demonstrated a capsaicin-induced peak shift in the two-dimensional motion maps at the N-terminus of the TRPV1 protein, but the peak shift was not obvious in the C-terminus. The capsaicin-induced motion modulation was recovered by the addition of the competitive inhibitor AMG9810.

Video-based analysis of the blink reflex in Parkinson's disease patients.

We developed a video-based tool to quantitatively assess the Glabellar Tap Reflex (GTR) in patients with idiopathic Parkinson's disease (iPD) as well as healthy age-matched participants. We also video-graphically assessed the effect of dopaminergic medication on the GTR in iPD patients, as well as the frequency and blinking duration of reflex and non-reflex blinks. The Glabellar Tap Reflex is a clinical sign seen in patients e.g. suffering from iPD. Reliable tools to quantify this sign are lacking. METHODS: We recorded the GTR in 11 iPD patients and 12 healthy controls (HC) with a consumer-grade camera at a framerate of at least 180 images/s. In these videos, reflex and non-reflex blinks were analyzed for blink count and blinking duration in an automated fashion. RESULTS: With our setup, the GTR can be extracted from high-framerate cameras using landmarks of the MediaPipe face algorithm. iPD patients did not habituate to the GTR; dopaminergic medication did not alter that response. iPD patients' non-reflex blinks were higher in frequency and higher in blinking duration (width at half prominence); dopaminergic medication decreased the median frequency (Before medication-HC: p < 0.001, After medication-HC: p = 0.0026) and decreased the median blinking duration (Before medication-HC: p = 0.8594, After medication-HC: p = 0.6943)-both in the direction of HC. CONCLUSION: We developed a quantitative, video-based tool to assess the GTR and other blinking-specific parameters in HC and iPD patients. Further studies could compare the video data to electromyogram (EMG) data for accuracy and comparability, as well as evaluate the specificity of the GTR in patients with other neurodegenerative disorders, in whom the GTR can also be present. SIGNIFICANCE: The video-based detection of the blinking parameters allows for unobtrusive measurement in patients, a safer and more comfortable option.

Temporal-Focusing Multiphoton Excitation Single-Molecule Localization Microscopy Using Spontaneously Blinking Fluorophores.

Single-molecule localization microscopy (SMLM) based on temporal-focusing multiphoton excitation (TFMPE) and single-wavelength excitation is used to visualize the three-dimensional (3D) distribution of spontaneously blinking fluorophore-labeled subcellular structures in a thick specimen with a nanoscale-level spatial resolution. To eliminate the photobleaching effect of unlocalized molecules in out-of-focus regions for improving the utilization rate of the photon budget in 3D SMLM imaging, SMLM with single-wavelength TFMPE achieves wide-field and axially confined two-photon excitation (TPE) of spontaneously blinking fluorophores. TPE spectral measurement of blinking fluorophores is then conducted through TFMPE imaging at a tunable excitation wavelength, yielding the optimal TPE wavelength for increasing the number of detected photons from a single blinking event during SMLM. Subsequently, the TPE fluorescence of blinking fluorophores is recorded to obtain a two-dimensional TFMPE-SMLM image of the microtubules in cancer cells with a localization precision of 18±6 nm and an overall imaging resolution of approximately 51 nm, which is estimated based on the contribution of Nyquist resolution and localization precision. Combined with astigmatic imaging, the system is capable of 3D TFMPE-SMLM imaging of brain tissue section of a 5XFAD transgenic mouse with the pathological features of Alzheimer's disease, revealing the distribution of neurotoxic amyloid-beta peptide deposits.

Interpersonal eye-tracking reveals the dynamics of interacting minds.

The human eye is a rich source of information about where, when, and how we attend. Our gaze paths indicate where and what captures our attention, while changes in pupil size can signal surprise, revealing our expectations. Similarly, the pattern of our blinks suggests levels of alertness and when our attention shifts between external engagement and internal thought. During interactions with others, these cues reveal how we coordinate and share our mental states. To leverage these insights effectively, we need accurate, timely methods to observe these cues as they naturally unfold. Advances in eye-tracking technology now enable real-time observation of these cues, shedding light on mutual cognitive processes that foster shared understanding, collaborative thought, and social connection. This brief review highlights these advances and the new opportunities they present for future research.

Facet Dependent Photoluminescence Blinking from Perovskite Nanocrystals.

Photoluminescence (PL) blinking of nanoparticles, while detrimental to their imaging applications, may benefit next-generation displays if the blinking is precisely controlled by reversible electron/hole injections from an external source. Considerable efforts are made to create well-characterized charged excitons within nanoparticles through electrochemical charging, which has led to enhanced control over PL-blinking in numerous instances. Manipulating the photocharging/discharging rates in nanoparticles by surface engineering can represent a straightforward method for regulating their blinking behaviors, an area largely unexplored for perovskite nanocrystals (PNCs). This work shows facet engineering leading to different morphologies of PNCs characterized by distinct blinking patterns. For instance, examining the PL intensity trajectories of single PNCs, representing the instantaneous photon count rate over time, reveals that the OFF-state population significantly increases as the number of facets increases from six to twenty-six. This study suggests that extra-faceted PNCs, owing to their polar facets and expanded surface area, render them more susceptible to photocharging, which results in larger OFF-state populations. Furthermore, the fluorescence correlation spectroscopy (FCS) study unveils that the augmented propensity for photocharging in extra-faceted PNCs can also originate from their greater tendency to form complexes with neighboring molecules.

Blinking Carbon Dots as a Super-resolution Imaging Probe.

Single-molecule localization microscopy (SMLM) emerges as a powerful approach for super-resolution imaging that provides unprecedented resolution at the nanometer length scale. However, the development of appropriate probes with specific photophysical traits and characteristics is crucial for this approach. This study demonstrates two different fluorescent carbon dots (CDs) derived from the same molecular precursor─one emitting in red and the other in green─as a SMLM-based super-resolution imaging probe for different applications with an average localization precision of 20 nm and a resolution of 60 nm. Both the CDs exhibit spontaneous blinking with high photon count and low duty cycle but with different blinking cycles. The red emissive CDs with a lower blinking cycle are ideal for quantitative analysis, whereas green emissive CDs with a higher blinking cycle are ideal for high-resolution imaging. We show that the difference in blinking features is linked to their chemical compositions, and the presence of much denser trap states in red emitting CDs is responsible for the reduction of its blinking cycle. This study shows that CDs can be designed as a potential probe for SMLM-based super-resolution imaging for diverse bioimaging applications.

Neural control of blinking.

Blinking is a motor act characterized by the sequential closing and opening of the eyelids, which is achieved through the reciprocal activation of the orbicularis oculi and levator palpebrae superioris muscles. This stereotyped movement can be triggered reflexively, occur spontaneously, or voluntarily initiated. During each type of blinking, the neural control of the antagonistic interaction between the orbicularis oculi and levator palpebrae superioris muscles is governed by partially overlapping circuits distributed across cortical, subcortical, and brainstem structures. This paper provides a comprehensive overview of the anatomical and physiological foundations underlying the neural control of blinking. We describe the infra-nuclear apparatus, as well as the supra-nuclear control mechanisms, i.e., how cortical, subcortical, and brainstem structures regulate and coordinate the different types of blinking.

End-of-day assessment of asymptomatic versus highly symptomatic soft contact lens wearers.

PURPOSE: To investigate differences in key clinical parameters between asymptomatic and highly symptomatic soft contact lens (CL) wearers after 14 h of wear. METHODS: In this pilot investigation, Phase 1 identified asymptomatic (CLDEQ-8 score ≤ 7) and highly symptomatic (CLDEQ-8 score ≥ 20) subjects after fitting with nelfilcon A CLs. Phase 2 investigated the following over a single nelfilcon A CL-wearing day (14 ± 2 h): blinking characteristics, tear meniscus height (TMH), non-invasive tear break-up time (NIBUT), tear film osmolarity and eyelid margin staining. Parameters for the two groups were compared using linear mixed models and post-hoc testing. The relationship between comfort scores and the clinical parameters was also investigated. RESULTS: Overall, 161 and 42 subjects were enrolled into Phase 1 and 2, respectively. Twenty-five asymptomatic and 17 symptomatic subjects completed Phase 2. Lower eyelid TMH was decreased after 14 h in symptomatic compared with asymptomatic subjects (least square mean [LSM] difference -0.04 mm, 95% CI: -0.07, -0.01). Osmolarity was lower in symptomatic than in asymptomatic subjects at fitting (LSM difference -9.89, 95% CI: -18.91, -0.86). Upper eyelid margin staining was greater after 14 h in symptomatic than in asymptomatic subjects (LSM difference 0.53, 95% CI: 0.01, 1.05) and greater after 14 h than baseline in the symptomatic group (LSM difference 0.61, 95% CI: 0.16, 1.07). There was a significant relationship between comfort and upper eyelid margin staining (r = -0.40, 95% CI: -0.63, -0.11) and blink rate (r = -0.31, 95% CI: -0.57, -0.003). CONCLUSION: The potential parameters most effective in differentiating asymptomatic from symptomatic wearers were upper eyelid margin staining and lower TMH. The parameter with the strongest relationship to comfort was upper eyelid margin staining, where higher comfort scores were associated with lower levels of staining.

Ocular effects of exposure to low-humidity environment with contact lens wear: A pilot study.

PURPOSE: To compare the ocular effects of exposure to a low-humidity environment with and without contact lens (CL) wear using various non-invasive tests. METHODS: Fourteen habitual soft CL wearers were exposed to controlled low humidity (5% relative humidity [RH]) in an environmental chamber for 90 min on two separate occasions. First, when wearing their habitual spectacles and then, on a separate visit, when wearing silicone hydrogel CLs that were fitted specifically for this purpose. All participants had adapted to the new CL prior to data collection. Three non-invasive objective measurements were taken at each visit: blinking rate, objective ocular scatter (measured using the objective scatter index) and ocular surface cooling rate (measured using a long-wave infrared thermal camera). At each visit, measurements were taken before the exposure in comfortable environmental conditions (RH: 45%), and after exposure to environmental stress (low humidity, RH: 5%). RESULTS: CL wearers showed increased blinking rate (p < 0.005) and ocular scatter (p = 0.03) but similar cooling rate of the ocular surface (p = 0.08) when compared with spectacle wear in comfortable environmental conditions. The exposure to low humidity increased the blinking rate significantly with both types of corrections (p = 0.01). Interestingly, ocular scatter (p = 0.96) and cooling rate (p = 0.73) were not significantly different before and after exposure to low humidity. There were no significant two-way interactions between correction and exposure in any of the measurements. CONCLUSIONS: CLs significantly increased the blinking rate, which prevented a quick degradation of the tear film integrity as it was refreshed more regularly. It is hypothesised that the increased blinking rate in CL wearers aids in maintaining ocular scatter quality and cooling rate when exposed to a low-humidity environment. These results highlight the importance of blinking in maintaining tear film stability.

Power Scavenging Microsystem for Smart Contact Lenses.

On-the-eye microsystems such as smart contacts for vision correction, health monitoring, drug delivery, and displaying information represent a new emerging class of low-profile (≤ 1 mm) wireless microsystems that conform to the curvature of the eyeball surface. The implementation of suitable low-profile power sources for eye-based microsystems on curved substrates is a major technical challenge addressed in this paper. The fabrication and characterization of a hybrid energy generation unit composed of a flexible silicon solar cell and eye-blinking activated Mg-O2 metal-air harvester capable of sustainably supplying electrical power to smart ocular devices are reported. The encapsulated photovoltaic device provides a DC output with a power density of 42.4 µW cm-2 and 2.5 mW cm-2 under indoor and outdoor lighting conditions, respectively. The eye-blinking activated Mg-air harvester delivers pulsed power output with a maximum power density of 1.3 mW cm-2. A power management circuit with an integrated 11 mF supercapacitor is used to convert the harvesters' pulsed voltages to DC, boost up the voltages, and continuously deliver ≈150 µW at a stable 3.3 V DC output. Uniquely, in contrast to wireless power transfer, the power pack continuously generates electric power and does not require any type of external accessories for operation.

Comparison of deep learning-assisted blinking analysis system and Lipiview interferometer in dry eye patients: a cross-sectional study.

BACKGROUND: Abnormal blinking pattern is associated with ocular surface diseases. However, blink is difficult to analyze due to the rapid movement of eyelids. Deep learning machine (DLM) has been proposed as an optional tool for blinking analysis, but its clinical practicability still needs to be proven. Therefore, the study aims to compare the DLM-assisted Keratograph 5M (K5M) as a novel method with the currently available Lipiview in the clinic and assess whether blinking parameters can be applied in the diagnosis of dry eye disease (DED). METHODS: Thirty-five DED participants and 35 normal subjects were recruited in this cross-sectional study. DED questionnaire and ocular surface signs were evaluated. Blinking parameters including number of blinks, number of incomplete blinking (IB), and IB rate were collected from the blinking videos recorded by the K5M and Lipiview. Blinking parameters were individually collected from the DLM analyzed K5M videos and Lipiview generated results. The agreement and consistency of blinking parameters were compared between the two devices. The association of blinking parameters to DED symptoms and signs were evaluated via heatmap. RESULTS: In total, 140 eyes of 70 participants were included in this study. Lipiview presented a higher number of IB and IB rate than those from DLM-assisted K5M (P ≤ 0.006). DLM-assisted K5M captured significant differences in number of blinks, number of IB and IB rate between DED and normal subjects (P ≤ 0.035). In all three parameters, DLM-assisted K5M also showed a better consistency in repeated measurements than Lipiview with higher intraclass correlation coefficients (number of blinks: 0.841 versus 0.665; number of IB: 0.750 versus 0.564; IB rate: 0.633 versus 0.589). More correlations between blinking parameters and DED symptoms and signs were found by DLM-assisted K5M. Moreover, the receiver operating characteristic analysis showed the number of IB from K5M exhibiting the highest area under curve of 0.773. CONCLUSIONS: DLM-assisted K5M is a useful tool to analyze blinking videos and detect abnormal blinking patterns, especially in distinguishing DED patients from normal subjects. Large sample investigations are therefore warranted to assess its clinical utility before implementation.

Interventional device tracking under MRI via alternating current controlled inhomogeneities.

PURPOSE: To introduce alternating current-controlled, conductive ink-printed marker that could be implemented with both custom and commercial interventional devices for device tracking under MRI using gradient echo, balanced SSFP, and turbo spin-echo sequences. METHODS: Tracking markers were designed as solenoid coils and printed on heat shrink tubes using conductive ink. These markers were then placed on three MR-compatible test samples that are typically challenging to visualize during MRI scans. MRI visibility of markers was tested by applying alternating and direct current to the markers, and the effects of applied current parameters (amplitude, frequency) on marker artifacts were tested for three sequences (gradient echo, turbo spin echo, and balanced SSFP) in a gel phantom, using 0.55T and 1.5T MRI scanners. Furthermore, an MR-compatible current supply circuit was designed, and the performance of the current-controlled markers was tested in one postmortem animal experiment using the current supply circuit. RESULTS: Direction and parameters of the applied current were determined to provide the highest conspicuity for all three sequences. Marker artifact size was controlled by adjusting the current amplitude, successfully. Visibility of a custom-designed, 20-gauge nitinol needle was increased in both in vitro and postmortem animal experiments using the current supply circuit. CONCLUSION: Current-controlled conductive ink-printed markers can be placed on custom or commercial MR-compatible interventional tools and can provide an easy and effective solution to device tracking under MRI for three sequences by adjusting the applied current parameters with respect to pulse sequence parameters using the current supply circuit.

Bright Nonblinking Photoluminescence with Blinking Lifetime from a Nanocavity-Coupled Quantum Dot.

Colloidal quantum dots (QDs) are excellent luminescent nanomaterials for many optoelectronic applications. However, photoluminescence blinking has limited their practical use. Coupling QDs to plasmonic nanostructures shows potential in suppressing blinking. However, the underlying mechanism remains unclear and debated, hampering the development of bright nonblinking dots. Here, by deterministically coupling a QD to a plasmonic nanocavity, we clarify the mechanism and demonstrate unprecedented single-QD brightness. In particular, we report for the first time that a blinking QD could obtain nonblinking photoluminescence with a blinking lifetime through coupling to the nanocavity. We show that the plasmon-enhanced radiative decay outcompetes the nonradiative Auger process, enabling similar quantum yields for charged and neutral excitons in the same dot. Meanwhile, we demonstrate a record photon detection rate of 17 MHz from a colloidal QD, indicating an experimental photon generation rate of more than 500 MHz. These findings pave the way for ultrabright nonblinking QDs, benefiting diverse QD-based applications.