Optical Nonlinearity Enabled Super-Resolved Multiplexing Microscopy.

Optical multiplexing for nanoscale object recognition is of great significance within the intricate domains of biology, medicine, anti-counterfeiting, and microscopic imaging. Traditionally, the multiplexing dimensions of nanoscopy are limited to emission intensity, color, lifetime, and polarization. Here, a novel dimension, optical nonlinearity, is proposed for super-resolved multiplexing microscopy. This optical nonlinearity is attributable to the energy transitions between multiple energy levels of the doped lanthanide ions in upconversion nanoparticles (UCNPs), resulting in unique optical fingerprints for UCNPs with different compositions. A vortex beam is applied to transport the optical nonlinearity onto the imaging point-spread function (PSF), creating a robust super-resolved multiplexing imaging strategy for differentiating UCNPs with distinctive optical nonlinearities. The composition information of the nanoparticles can be retrieved with variations of the corresponding PSF in the obtained image. Four channels multiplexing super-resolved imaging with a single scanning, applying emission color and nonlinearity of two orthogonal imaging dimensions with a spatial resolution higher than 150 nm (1/6.5λ), are demonstrated. This work provides a new and orthogonal dimension - optical nonlinearity - to existing multiplexing dimensions, which shows great potential in bioimaging, anti-counterfeiting, microarray assays, deep tissue multiplexing detection, and high-density data storage.

In vitro evaluation of a hybrid drug-delivery nanosystem for fibrosis prevention in cell therapy for Type 1 diabetes.

Background: Implantation of insulin-secreting cells has been trialed as a treatment for Type 1 diabetes mellitus; however, the host immunogenic response limits their effectiveness. Methodology: The authors developed a core-shell nanostructure of upconversion nanoparticle-mesoporous silica for controlled local delivery of an immunomodulatory agent, MCC950, using near-infrared light and validated it in in vitro models of fibrosis. Results: The individual components of the nanosystem did not affect the proliferation of insulin-secreting cells, unlike fibroblast proliferation (p < 0.01). The nanosystem is effective at releasing MCC950 and preventing fibroblast differentiation (p < 0.01), inflammation (IL-6 expression; p < 0.05) and monocyte adhesion (p < 0.01). Conclusion: This MCC950-loaded nanomedicine system could be used in the future together with insulin-secreting cell implants to increase their longevity as a curative treatment for Type 1 diabetes mellitus.

This work describes a new drug-delivery system that can release an immunomodulatory drug in a controlled manner and prevent fibrosis, which is part of the immune response when a foreign body is implanted. This system can be particularly useful for insulin-secreting cell implants, used to replace multiple daily injections of insulin and improve the quality of life of people with Type 1 diabetes mellitus. By preventing the immune response that leads to fibrosis, the longevity of these cellular implants can be extended without the need for frequent replacement procedures. This innovative nanosystem can release the required amount of immunomodulatory drug, which could be stimulated with the use of special light, hence showing the ability for local and extended delivery. This type of system has the potential to reduce the side effects associated with oral daily administration of immunomodulatory agents in people with Type 1 diabetes mellitus.

Lanthanide Ion Resonance-Driven Rayleigh Scattering of Nanoparticles for Dual-Modality Interferometric Scattering Microscopy.

Light scattering from nanoparticles is significant in nanoscale imaging, photon confinement. and biosensing. However, engineering the scattering spectrum, traditionally by modifying the geometric feature of particles, requires synthesis and fabrication with nanometre accuracy. Here it is reported that doping lanthanide ions can engineer the scattering properties of low-refractive-index nanoparticles. When the excitation wavelength matches the ion resonance frequency of lanthanide ions, the polarizability and the resulted scattering cross-section of nanoparticles are dramatically enhanced. It is demonstrated that these purposely engineered nanoparticles can be used for interferometric scattering (iSCAT) microscopy. Conceptually, a dual-modality iSCAT microscopy is further developed to identify different nanoparticle types in living HeLa cells. The work provides insight into engineering the scattering features by doping elements in nanomaterials, further inspiring exploration of the geometry-independent scattering modulation strategy.

Exploiting Dynamic Nonlinearity in Upconversion Nanoparticles for Super-Resolution Imaging.

Single-beam super-resolution microscopy, also known as superlinear microscopy, exploits the nonlinear response of fluorescent probes in confocal microscopy. The technique requires no complex purpose-built system, light field modulation, or beam shaping. Here, we present a strategy to enhance this technique's spatial resolution by modulating excitation intensity during image acquisition. This modulation induces dynamic optical nonlinearity in upconversion nanoparticles (UCNPs), resulting in variations of nonlinear fluorescence response in the obtained images. The higher orders of fluorescence response can be extracted with a proposed weighted finite difference imaging algorithm from raw fluorescence images to generate an image with higher resolution than superlinear microscopy images. We apply this approach to resolve single nanoparticles in a large area, improving the resolution to 132 nm. This work suggests a new scope for the development of dynamic nonlinear fluorescent probes in super-resolution nanoscopy.

How Wealth Inequality Affects Happiness: The Perspective of Social Comparison.

Since Easterlin pointed out that economic growth in nations does not guarantee increasing happiness for the average citizen, the underlying reason has remained controversial. The present study focuses on income inequality to explain the "Easterlin Paradox," ignoring the permanent inequality that long-term wealth accumulation brings. Based on social comparison theory, the literature aims to determine how wealth inequality, which accompanies economic growth, diminishes one's happiness (inequality aversion). Specifically, we conduct this study in which we split the wealth inequality into the upward wealth inequality and the downward wealth inequality as measures of upward comparison and downward comparison, respectively. The upward wealth inequality measures the average gap between one and the better-off in wealth while the downward wealth inequality measures the average gap between one and the worse-off in wealth. Furthermore, the heterogeneity of the area of respondent is analyzed and the family life cycle is tested as a moderator. The main findings of the paper are as follows: (1) The empirical test results of hypothesis 1 indicate that the upward wealth inequality aversion (jealousy effect: people envy who is richer than themselves) is stronger than the downward wealth inequality inclination (proud effect: people enjoy having a superior position in the wealth hierarchy). It is due to the psychological preference: loss aversion. As an increase in upward distance implies a loss in relative status and an increase in downward distance implies a gain in relative status, people focus more on loss rather than gain. (2) The empirical test results of hypothesis 2 indicate that residents who live in rural areas do not have a proud effect as much as those who live in urban areas. There is a huge urban-rural wealth gap in China. With the expansion of the social network, people living in rural areas realize that even he is almost the rich in rural areas but still the lower classes in the whole society. It is hard for rural residents to have a proud effect. (3) The empirical test results of hypothesis 3 indicate that family members have the strongest upward inequality aversion in the middle-stage phase of the life cycle (when the family head is approximately 50). During the family life cycle, inequality aversion will be different in different life stages due to the changes in economic status expectations. At the beginning of the family life cycle, family members assume their life has limitless possibilities, and they have high expectations for the future. Logically, they can be easily satisfied by achieving a little more than their peers. In later periods, with increasing age, the members will pay more attention to health instead of wealth. The results shed light on how macroeconomics influence changes in individual psychology.

Fabrication and characterization of ZnO nanofilms using extracted pectin of Premna microphylla Turcz leaves and carboxymethyl cellulose.

The current study sought to fabricate pectin nano-films from Premna microphylla Turcz (PMTP) leaves using a combination of ZnO-carboxymethyl cellulose. The rheological and physical properties of fabricated nano-ZnO films were studied. Spectroscopy FT-IR, microscopic study (SEM), thermogravimetry (TG), and XRD were applied to characterize the fabricated film. The antibacterial activity of the nanofilm was determined using the antibacterial circle method. The findings showed that the addition of PMTP can reduce the nanofilm color, water solubility/hydrophilicity, air permeability, and ultraviolet light permeability of the nanofilm. Treatment CPN0.5 achieved the optimized Tensile strength (TS) of 4.50 Mpa, significant differences compared to CPN2 (3.99 Mpa) and CPN1 (3.65 Mpa). In addition, treatment CPN1 achieved the lowest WVP value (29.35) compared to the highest value (41.62) achieved by CPN0.5 treatment with no significant differences with CPN3 (29.7) and CPN1 (30.98) treatments. Elongation (E%) at break was the best for each CP10 (74.9) and CPN0.5 (73.03). Moreover, ZnO can enhance the nanofilm activity and the nanofilm water swelling ratio. Furthermore, adding ZnO to the nano-formula improved the antibacterial activity of the fabricated film against Staphylococcus aureus. In sum, nanofilms fabricated of PMTP and ZnO possess promising prospects as antibacterial agents in packaging applications.

Smart Drug-Delivery System of Upconversion Nanoparticles Coated with Mesoporous Silica for Controlled Release.

Drug-delivery vehicles have garnered immense interest in recent years due to unparalleled progress made in material science and nanomedicine. However, the development of stimuli-responsive devices with controllable drug-release systems (DRSs) is still in its nascent stage. In this paper, we designed a two-way controlled drug-release system that can be promoted and prolonged, using the external stimulation of near-infrared light (NIR) and protein coating. A hierarchical nanostructure was fabricated using upconversion nanoparticles (UCNPs)-mesoporous silica as the core-shell structure with protein lysozyme coating. The mesoporous silica shell provides abundant pores for the loading of drug molecules and a specific type of photosensitive molecules. The morphology and the physical properties of the nanostructures were thoroughly characterized. The results exhibited the uniform core-shell nanostructures of ~four UCNPs encapsulated in one mesoporous silica nanoparticle. The core-shell nanoparticles were in the spherical shape with an average size of 200 nm, average surface area of 446.54 m2/g, and pore size of 4.6 nm. Using doxorubicin (DOX), a chemotherapy agent as the drug model, we demonstrated that a novel DRS with capacity of smart modulation to promote or inhibit the drug release under NIR light and protein coating, respectively. Further, we demonstrated the therapeutic effect of the designed DRSs using breast cancer cells. The reported novel controlled DRS with dual functionality could have a promising potential for chemotherapy treatment of solid cancers.

Characterization of Upconversion Nanoparticles by Single-Particle ICP-MS Employing a Quadrupole Mass Filter with Increased Bandpass.

This work introduces new methods to characterize dispersions of small-diameter or low-mass-fraction nanoparticles (NPs) by single-particle inductively coupled plasma-mass spectrometry (SP ICP-MS). The optimization of ion extraction, ion transport, and the operation of the quadrupole with increased mass bandwidth improved the signal-to-noise ratios significantly and decreased the size detection limits for all NP dispersions investigated. As a model system, 10.9 ± 1.0 nm Au NPs were analyzed to demonstrate the effects of increasing ion transmission. Specifically, increasing the mass bandwidth of the quadrupole improved the size detection limit to 4.2 nm and enabled the resolution of NP signals from ionic background and noise. Subsequently, the methods were applied to the characterization of lanthanide-doped upconversion nanoparticles (UCNPs) by SP ICP-MS. Three different types of UCNPs (90 nm NaYF4: 20% Yb, 2% Er; 20 nm NaGdF4: 20% Yb, 1% Er; 15 nm NaYF4: 20% Yb, 2% Er) were investigated. Y showed the best signal-to-noise ratios with optimized ion extraction and transport parameters only, whereas the signal-to-noise ratios of Gd, Er, and Yb were further improved by increasing the mass bandwidth of a quadrupole mass filter. The novel methods were suitable for detailed characterization of diluted UCNP dispersions including particle stoichiometries and size distributions. A Poisson model was further applied to assess particle-particle interactions in the aqueous dispersions. The methods have considerable potential for the characterization of small-diameter and/or low-mass-fraction nanoparticles.

Photonic Nanobeam Cavities with Nanopockets for Efficient Integration of Fluorescent Nanoparticles.

Integrating fluorescent nanoparticles with high-Q, small mode volume cavities is indispensable for nanophotonics and quantum technologies. To date, nanoparticles have largely been coupled to evanescent fields of cavity modes, which limits the strength of the interaction. Here, we developed both a cavity design and a fabrication method that enable efficient coupling between a fluorescent nanoparticle and a cavity optical mode. The design consists of a fishbone-shaped, one-dimensional photonic crystal cavity with a nanopocket located at the electric field maximum of the fundamental optical mode. Furthermore, the presence of a nanoparticle inside the pocket reduces the mode volume substantially and induces subwavelength light confinement. Our approach opens exciting pathways to achieve tight light confinement around fluorescent nanoparticles for applications in energy, sensing, lasing, and quantum technologies.