Seed mediated one-pot growth of versatile heterogeneous upconversion nanocrystals for multimodal bioimaging

© 2016 SPIE. The rapid development of a variety of molecular contrast agents makes the multimodality bioimaging highly attractive towards higher resolution, more sensitive, informative diagnosis. The key lies in the development of facile material synthesis that allows the integration of multiple contrast agents, ideally in a way that each of the components should be logically assembled to maximize their performances. Here, we report the one-pot programmable growth of multifunctional heterogeneous nanocrystal with tunable size, shape, composition, and properties. We demonstrated a facile one-pot hot-injection method to enable the highly selectively controlled growth of different sodium lanthanide fluoride nanomaterials in either longitudinal or transversal directions with atomic scale precision. This technique allows the upconversion luminescence signal, MRI signal and x-ray signal logically integrated and optimized within one single versatile nanoplatform for multimode bioimaging. These findings suggest that the facile strategy developed here have the promising to get the desired heterogeneous nanocrystals as an all-in-one contrast agent for integrated and self-correlative multimodal bioimaging

Gravitating Global k-monopole

A gravitating global k-monopole produces a tiny gravitational field outside the core in addition to a solid angular deficit in the k-field theory. As a new feature, the gravitational field can be attractive or repulsive depending on the non-canonical kinetic term.Comment: 9 pages, 2 figures, references added, typos corrected, accepted by Class. Quantum Gra

Hepatitis B virus subgenotype C2 is the most prevalent subgenotype in northeast China

AbstractThe geographical distribution of hepatitis B virus (HBV) subgenotypes and their clinical implications in patients with acute and chronic hepatitis B in the Heilung-kiang province of northeast China were investigated. Nested PCR and multiplex PCR were performed with genotype-specific primers and with subgenotype-specific primers to identify genotypes and subgenotypes from serum samples of 412 HBV infections including 69 with acute self-limited hepatitis (ASH) and 343 with chronic hepatitis (CH). A total of 361 samples were genotyped and 304 were further subgenotyped. The most common HBV genotype was C (93.63%, 338/361), with subgenotype group C2 (83.73%, 283/338) predominating. Genotype B was also found and subgenotype B2 predominated within this genotype. Out of 69 infected patients with ASH, 48 were identified as genotype C and all belonged to subgenotype C2. Of 343 infected patients with CH, 313 were genotyped and 256 were subgenotyped; amongst these, C2 (91.80%, 235/256), B2 (7.42%, 19/256) and mixed subgenotypes B2 and C2 (0.78%, 2/256) were found. In HBV subgenotype C2 infections, ASH had a higher ratio of women than CH patients. These results show that HBV subgenotypes C2 and B2 were found in Heilung-kiang province of northeast China. In ASH and CH groups, the distributions of subgenotypes were coincident with C2, the predominant subgenotype. Analysis of the association between subgenotype and the outcomes of HBV infection was inconclusive in our study

High-dimensional super-resolution imaging reveals heterogeneity and dynamics of subcellular lipid membranes.

Lipid membranes are found in most intracellular organelles, and their heterogeneities play an essential role in regulating the organelles' biochemical functionalities. Here we report a Spectrum and Polarization Optical Tomography (SPOT) technique to study the subcellular lipidomics in live cells. Simply using one dye that universally stains the lipid membranes, SPOT can simultaneously resolve the membrane morphology, polarity, and phase from the three optical-dimensions of intensity, spectrum, and polarization, respectively. These high-throughput optical properties reveal lipid heterogeneities of ten subcellular compartments, at different developmental stages, and even within the same organelle. Furthermore, we obtain real-time monitoring of the multi-organelle interactive activities of cell division and successfully reveal their sophisticated lipid dynamics during the plasma membrane separation, tunneling nanotubules formation, and mitochondrial cristae dissociation. This work suggests research frontiers in correlating single-cell super-resolution lipidomics with multiplexed imaging of organelle interactome

Gold-viral particle identification by deep learning in wide-field photon scattering parametric images

The ability to identify virus particles is important for research and clinical applications. Because of the optical diffraction limit, conventional optical microscopes are generally not suitable for virus particle detection, and higher resolution instruments such as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are required. In this paper, we propose a new method for identifying virus particles based on polarization parametric indirect microscopic imaging (PIMI) and deep learning techniques. By introducing an abrupt change of refractivity at the virus particle using antibody-conjugated gold nanoparticles (AuNPs), the strength of the photon scattering signal can be magnified. After acquiring the PIMI images, a deep learning method was applied to identify discriminating features and classify the virus particles, using electron microscopy (EM) images as the ground truth. Experimental results confirm that gold-virus particles can be identified in PIMI images with a high level of confidence

Highly Doped Upconversion Nanoparticles for In Vivo Applications Under Mild Excitation Power.

One of the major challenges in using upconversion nanoparticles (UCNPs) is to improve their brightness. This is particularly true for in vivo studies, as the low power excitation is required to prevent the potential photo toxicity to live cells and tissues. Here, we report that the typical NaYF4:Yb0.2,Er0.02 nanoparticles can be highly doped, and the formula of NaYF4:Yb0.8,Er0.06 can gain orders of magnitude more brightness, which is applicable to a range of mild 980 nm excitation power densities, from 0.005 W/cm2 to 0.5 W/cm2. Our results reveal that the concentration of Yb3+ sensitizer ions plays an essential role, while increasing the doping concentration of Er3+ activator ions to 6 mol % only has incremental effect. We further demonstrated a type of bright UCNPs 12 nm in total diameter for in vivo tumor imaging at a power density as low as 0.0027 W/cm2, bringing down the excitation power requirement by 42 times. This work redefines the doping concentrations to fight for the issue of concentration quenching, so that ultrasmall and bright nanoparticles can be used to further improve the performance of upconversion nanotechnology in photodynamic therapy, light-triggered drug release, optogenetics, and night vision enhancement

Bcl-2 inhibitor uploaded upconversion nanophotosensitizers to overcome the photodynamic therapy resistance of cancer through adjuvant intervention strategy

Similar to many other anticancer therapies, photodynamic therapy (PDT) also suffers from the intrinsic cancer resistance mediated by cell survival pathways. These survival pathways are regulated by various proteins, among which anti-apoptotic protein Bcl-2 plays an important role in regulation of programmed cell death and has been proved to involve in protecting against oxidative stimuli. Confronted by this challenge, we propose and validate here a novel upconversion photosensitizing nanoplatform which enables significant reduction of cancer resistance and improve PDT efficacy. The upconversion nano-photosensitizer contains the photosensitizing molecules - Zinc phthalocyanine (ZnPc) and Bcl-2 inhibitor - ABT737 small molecules, denoted as ABT737@ZnPc-UCNPs. ABT737 molecules were encapsulated, in a pH sensitive way, into the nanoplatform through Poly (ethylene glycol)-Poly (L-histidine) diblock copolymers (PEG-b-PHis). This nanosystem exhibits the superiority of sensitizing tumor cells for PDT through adjuvant intervention strategy. Upon reaching to lysosomes, the acidic environment changes the solubility of PEG-b-PHis, resulting in the burst-release of ABT737 molecules which deplete the Bcl-2 level in tumor cells and leave the tumor cells out from the protection of anti-apoptotic survival pathway in advance. Owing to the sensitization effect of ABT737@ZnPc-UCNPs, the PDT therapeutic efficiency of cancer cells can be significantly potentiated in vitro and in vivo

Super-resolution imaging of fluorescent dipoles via polarized structured illumination microscopy

© 2019, The Author(s). Fluorescence polarization microscopy images both the intensity and orientation of fluorescent dipoles and plays a vital role in studying molecular structures and dynamics of bio-complexes. However, current techniques remain difficult to resolve the dipole assemblies on subcellular structures and their dynamics in living cells at super-resolution level. Here we report polarized structured illumination microscopy (pSIM), which achieves super-resolution imaging of dipoles by interpreting the dipoles in spatio-angular hyperspace. We demonstrate the application of pSIM on a series of biological filamentous systems, such as cytoskeleton networks and λ-DNA, and report the dynamics of short actin sliding across a myosin-coated surface. Further, pSIM reveals the side-by-side organization of the actin ring structures in the membrane-associated periodic skeleton of hippocampal neurons and images the dipole dynamics of green fluorescent protein-labeled microtubules in live U2OS cells. pSIM applies directly to a large variety of commercial and home-built SIM systems with various imaging modality