Light-field microscopy with temporal focusing multiphoton illumination for scanless volumetric bioimaging.

A temporal focusing multiphoton illumination (TFMI) method is proposed for achieving selective volume illumination (SVI) (i.e., illuminating only the volume of interest) in light-field microscopy (LFM). The proposed method minimizes the background noise of the LFM images and enhances the contrast, and thus improves the imaging quality. Three-dimensional (3D) volumetric imaging is achieved by reconstructing the LFM images using a phase-space deconvolution algorithm. The experimental results obtained using 100-nm fluorescent beads show that the proposed TFMI-LFM system achieves lateral and axial resolutions of 1.2 µm and 1.1 µm, respectively, at the focal plane. Furthermore, the TFMI-LFM system enables 3D images of the single lobe of the drosophila mushroom body with GFP biomarker (OK-107) to be reconstructed in a one-snapshot record.

Xenon blunts NF-κB/NLRP3 inflammasome activation and improves acute onset of accelerated and severe lupus nephritis in mice.

Xenon, an inert anesthetic gas, is increasingly recognized to possess desirable properties including cytoprotective and anti-inflammatory effects. Here we evaluated the effects of xenon on the progression of lupus nephritis (LN) in a mouse model. A two hour exposure of either 70% xenon or 70% nitrogen balanced with oxygen was administered daily for five weeks to female NZB/W F1 mice that had been induced to develop accelerated and severe LN. Xenon treatment improved kidney function and renal histology, and decreased the renal expression of neutrophil chemoattractants, thereby attenuating glomerular neutrophil infiltration. The effects of xenon were mediated primarily by deceasing serum levels of anti-double stranded DNA autoantibody, inhibiting reactive oxygen species production, NF-κB/NLRP3 inflammasome activation, ICAM-1 expression, glomerular deposition of IgG and C3 and apoptosis, in the kidney; and enhancing renal hypoxia inducible factor 1-α expression. Proteomic analysis revealed that the treatment with xenon downregulated renal NLRP3 inflammasome-mediated cellular signaling. Similarly, xenon was effective in improving renal pathology and function in a spontaneous LN model in female NZB/W F1 mice. Thus, xenon may have a therapeutic role in treating LN but further studies are warranted to determine applicability to patients.

The Making of a Flight Feather: Bio-architectural Principles and Adaptation.

The evolution of flight in feathered dinosaurs and early birds over millions of years required flight feathers whose architecture features hierarchical branches. While barb-based feather forms were investigated, feather shafts and vanes are understudied. Here, we take a multi-disciplinary approach to study their molecular control and bio-architectural organizations. In rachidial ridges, epidermal progenitors generate cortex and medullary keratinocytes, guided by Bmp and transforming growth factor ß (TGF-ß) signaling that convert rachides into adaptable bilayer composite beams. In barb ridges, epidermal progenitors generate cylindrical, plate-, or hooklet-shaped barbule cells that form fluffy branches or pennaceous vanes, mediated by asymmetric cell junction and keratin expression. Transcriptome analyses and functional studies show anterior-posterior Wnt2b signaling within the dermal papilla controls barbule cell fates with spatiotemporal collinearity. Quantitative bio-physical analyses of feathers from birds with different flight characteristics and feathers in Burmese amber reveal how multi-dimensional functionality can be achieved and may inspire future composite material designs. VIDEO ABSTRACT.

Rapid single-wavelength lightsheet localization microscopy for clarified tissue.

Optical super-resolution microscopy allows nanoscale imaging of protein molecules in intact biological tissues. However, it is still challenging to perform large volume super-resolution imaging for entire animal organs. Here we develop a single-wavelength Bessel lightsheet method, optimized for refractive-index matching with clarified specimens to overcome the aberrations encountered in imaging thick tissues. Using spontaneous blinking fluorophores to label proteins of interest, we resolve the morphology of most, if not all, dopaminergic neurons in the whole adult brain (3.64 × 107 µm3) of Drosophila melanogaster at the nanometer scale with high imaging speed (436 µm3 per second) for localization. Quantitative single-molecule localization reveals the subcellular distribution of a monoamine transporter protein in the axons of a single, identified serotonergic Dorsal Paired Medial (DPM) neuron. Large datasets are obtained from imaging one brain per day to provide a robust statistical analysis of these imaging data.

Lightsheet localization microscopy enables fast, large-scale, and three-dimensional super-resolution imaging.

Recent advances in super-resolution microscopy allow the localization of single molecules within individual cells but not within multiple whole cells due to weak signals from single molecules and slow acquisition process for point accumulation to reconstruct super-resolution images. Here, we report a fast, large-scale, and three-dimensional super-resolution fluorescence microscope based on single-wavelength Bessel lightsheet to selectively illuminate spontaneous blinking fluorophores tagged to the proteins of interest in space. Critical parameters such as labeling density, excitation power, and exposure time were systematically optimized resulting in a maximum imaging speed of 2.7 × 104 µm3 s-1. Fourier ring correlation analysis revealed a reconstructed image with a lateral resolution of ~75 nm through the accumulation of 250 image volumes on immobilized samples within 15 min. Hence, the designed system could open new insights into the discovery of complex biological structures and live 3D localization imaging.

Construction of single fluorophore ratiometric pH sensors using dual-emission Mn(2+)-doped quantum dots.

We present a novel ratiometric pH sensor design using water-soluble, dual-emission, Mn(2+)-doped quantum dots (Qdots) decorated with D-penicillamine (DPA-MnQdots). In contrast to more commonly used ratiometric pH sensors that rely on the coupling of two fluorophores, our design uses only a single emitter, which simplifies ratiometric sensing and broadens the applications of the sensor. Our single-emitter DPA-MnQdots exhibit two emission bands, at 510nm (green) and 610nm (red), which are, respectively, attributable to exciton recombination and emission of the Mn(2+) dopants. The emission intensity ratio (I510/I610) of the DPA-MnQdots depends linearly on surrounding pH values within physiological conditions (from pH 4.5 to 8.5). Moreover, the biocompatible DPA-MnQdots were used for long-term monitoring of local pH values in HeLa cells.

Evaluation of the intracellular uptake and cytotoxicity effect of TiO2 nanostructures for various human oral and lung cells under dark conditions.

Titanium dioxide (TiO2) nanomaterials (NMs) have been widely used to develop commercial products such as sunscreen cosmetics because of their unique optical properties to provide complete protection from ultraviolet (UV) light. The most dangerous type of UV radiation is UVA, which comprises nearly 97% of the UV radiation that reaches the Earth. This type of radiation is also the major cause of skin damage. As the most beneficial content of sunscreen cosmetics, TiO2 NMs exhibit immense capability to protect the human skin from UVA exposure through their scattering and reflecting physical properties. Therefore, investigating the factors involved in using TiO2 NMs in cosmetics is necessary. In this study, various human oral and lung cell lines were selected to evaluate the cytotoxicity of treatment using different sizes and shapes of TiO2 NMs, including spheres (AFDC and AFDC300) and rods (M212 and cNRs). The morphology, size, and crystalline phase of the selected TiO2 NMs were studied to characterize each physical property. Based on cell viability and endocytic behavior results, treatment with all the selected TiO2 NMs were nearly non-toxic to the oral cell lines. However, high cytotoxicity was obviously observed in lung cells with M212 and AFDC treatments at 50 µg mL-1, which was larger by approximately 20% than with ADC300 and cNRs treatments because the smaller the TiO2 NMs, the larger their specific surface area. This condition resulted in the progress of apoptosis from the considerable aggregation of TiO2 NMs in the cytoplasm. Moreover, compared with those of TiO2 NMs with a similar structure (e.g., cNRs) and size (e.g., M212), the cellular uptake of AFDC was evidently low, which resulted in the approximated non-toxicity. Moreover, the similar sizes and different shapes of AFDC and cNRs were considered to treat lung cells to investigate further the influence of morphology on the cell cycle and the apoptosis effect. Consequently, AFDC and cNRs could inhibit the growth of lung cells and allow a considerable proportion of the cells to remain in the G1/G0 phase. Furthermore, a high-dose treatment would directly induce the apoptosis pathway, whereas a low-dose treatment might decrease cell regeneration.

Optimizing cationic and neutral lipids for efficient gene delivery at high serum content.

BACKGROUND: Cationic liposome (CL)-DNA complexes are promising gene delivery vectors with potential application in gene therapy. A key challenge in creating CL-DNA complexes for application is that their transfection efficiency (TE) is adversely affected by serum. In particular, little is known about the effects of a high serum content on TE, even though this may provide design guidelines for application in vivo. METHODS: We prepared CL-DNA complexes in which we varied the neutral lipid [1,2-dioleoyl-sn-glycerophosphatidylcholine, glycerol-monooleate (GMO), cholesterol], the headgroup charge and chemical structure of the cationic lipid, and the ratio of neutral to cationic lipid; we then measured the TE of these complexes as a function of serum content and assessed their cytotoxicity. We tested selected formulations in two human cancer cell lines (M21/melanoma and PC-3/prostate cancer). RESULTS: In the absence of serum, all CL-DNA complexes of custom-synthesized multivalent lipids show high TE. Certain combinations of multivalent lipids and neutral lipids, such as MVL5(5+)/GMO-DNA complexes or complexes based on the dendritic-headgroup lipid TMVLG3(8+) exhibited high TE both in the absence and presence of serum. Although their TE still dropped to a small extent in the presence of serum, it reached or surpassed that of benchmark commercial transfection reagents, particularly at a high serum content. CONCLUSIONS: Two-component vectors (one multivalent cationic lipid and one neutral lipid) can rival or surpass benchmark reagents at low and high serum contents (up to 50%, v/v). We propose guidelines for optimizing the serum resistance of CL-DNA complexes based on a given cationic lipid.

Photothermal cancer therapy via femtosecond-laser-excited FePt nanoparticles.

FePt nanoparticles (NPs) have recently been revealed to be significant multifunctional materials for the applications of biomedical imaging, drug delivery and magnetic hyperthermia due to their novel magnetic properties. In this study, a newly discovered photothermal effect activated by the near infrared (NIR) femtosecond laser for FePt NPs was demonstrated. The threshold laser energy to destroy cancer cells was found to be comparable to that of gold nanorods (Au NRs) previously reported. Through the thermal lens technique, it was concluded that the temperature of the FePt NPs can be heated up to a couple of hundreds degree C in picoseconds under laser irradiation due to the excellent photothermal transduction efficiency of FePt NPs. This finding boosts FePt NPs versatility in multifunctional targeted cancer therapy.

Functionalized polymer spheres via one-step photoinduced synthesis for antimicrobial activity and gene delivery.

Despite the fact that polystyrene (PS) spheres have been developed as polymeric carriers or matrices for various biomedical applications, the synthesis of PS spheres is time-consuming. This work describes the fabrication of a uniform PS sphere, coated with silver nanoparticles (Ag-PS), by simultaneous photoinduced polymerization and reduction fabricated using x-rays in aqueous solution without any initiator. The solution contains only styrene, silver ions (Ag(+)), and poly(vinyl pyrrolidone) (PVP) as a stabilizer. The proposed mechanism of the formation of the Ag-PS nanocomposite spheres involves the generation of radicals in the aqueous solution to induce PS polymerization and the reduction of Ag. The distribution of the sizes of the core PS spheres in the Ag-PS nanocomposite spheres was systematically examined as a function of irradiation time, concentration of styrene, and amount of PVP. Ag-PS nanocomposite spheres exhibit antimicrobial activity against bacteria (Escherichia coli and Staphylococcus aureus). Additionally, the cationic (vinylbenzyl)trimethylammonium (TMA) monomer was photopolymerized to form positively charged TMA-PS spheres as gene carriers with uniquely low cytotoxicity. Given these design advantages, the method proposed herein is simpler than typical approaches for synthesizing PS spheres with functionalized groups and PS spheres coated with Ag nanoparticles.

Biocompatible transferrin-conjugated sodium hexametaphosphate-stabilized gold nanoparticles: synthesis, characterization, cytotoxicity and cellular uptake.

The feasibility of using gold nanoparticles (AuNPs) for biomedical applications has led to considerable interest in the development of novel synthetic protocols and surface modification strategies for AuNPs to produce biocompatible molecular probes. This investigation is, to our knowledge, the first to elucidate the synthesis and characterization of sodium hexametaphosphate (HMP)-stabilized gold nanoparticles (Au-HMP) in an aqueous medium. The role of HMP, a food additive, as a polymeric stabilizing and protecting agent for AuNPs is elucidated. The surface modification of Au-HMP nanoparticles was carried out using polyethylene glycol and transferrin to produce molecular probes for possible clinical applications. In vitro cell viability studies performed using as-synthesized Au-HMP nanoparticles and their surface-modified counterparts reveal the biocompatibility of the nanoparticles. The transferrin-conjugated nanoparticles have significantly higher cellular uptake in J5 cells (liver cancer cells) than control cells (oral mucosa fibroblast cells), as determined by inductively coupled plasma mass spectrometry. This study demonstrates the possibility of using an inexpensive and non-toxic food additive, HMP, as a stabilizer in the large-scale generation of biocompatible and monodispersed AuNPs, which may have future diagnostic and therapeutic applications.

Real time observation of mouse fetal skeleton using a high resolution X-ray synchrotron.

The X-ray synchrotron is quite different from conventional radiation sources. This technique may expand the capabilities of conventional radiology and be applied in novel manners for special cases. To evaluate the usefulness of X-ray synchrotron radiation systems for real time observations, mouse fetal skeleton development was monitored with a high resolution X-ray synchrotron. A non-monochromatized X-ray synchrotron (white beam, 5C1 beamline) was employed to observe the skeleton of mice under anesthesia at embryonic day (E)12, E14, E15, and E18. At the same time, conventional radiography and mammography were used to compare with X-ray synchrotron. After synchrotron radiation, each mouse was sacrificed and stained with Alizarin red S and Alcian blue to observe bony structures. Synchrotron radiation enabled us to view the mouse fetal skeleton beginning at gestation. Synchrotron radiation systems facilitate real time observations of the fetal skeleton with greater accuracy and magnification compared to mammography and conventional radiography. Our results show that X-ray synchrotron systems can be used to observe the fine structures of internal organs at high magnification.

A single-monomer derived linear-like PEI-co-PEG for siRNA delivery and silencing.

Polyethylenimines (PEIs) are commonly used as a vehicle to deliver and protect siRNA, but the strong interaction still remains to be modulated for efficient siRNA release and silencing. Herein, a single-monomer derived linear-like PEI-co-PEG (LPEI-co-PEG, P(2)) was synthesized to substantially enhance the siRNA release, but not affect the efficiency of protection. The linear-like copolymer (P(2)) was only synthesized from a single-monomer by intensive synchrotron X-ray irradiation within 5 min, randomly producing both PEI and PEG segments. The counterpart vehicle, LPEI (P(1)), was also synthesized for comparison. We found that the P(1) and P(2) were able to prevent siRNA against enzymatic degradation. Most importantly, efficient siRNA release (52%) was only observed in the siRNA/P(2) complexes and not in the siRNA/P(1) complexes (<5%), suggesting that the PEG segment may modulate the interaction between siRNA and P(2) segment. Specifically, P(2) as well as P(1) can emit photoluminescence; cancer cells exhibited a detectable photoluminescence after treatment with P(1) and P(2), indicative of their excellent transfection efficiency. Subsequently, the siGFP/P(2) complexes knocked down GFP with excellent efficiency (75%) above the siGFP/P(1) complexes (19%) and siGFP/Lipofectamine complexes (20%). Importantly, the siRNA with anti-VEGF function being associated with P(2) have been demonstrated an excellent efficiency in the suppression of tumor growth.

One-pot synthesis of linear-like and photoluminescent polyethylenimines for intracellular imaging and siRNA delivery.

Linear-like and photoluminescent polyethylenimines (LPEIs) were synthesized through a one-pot reaction within 5 min using synchrotron radiation for intracellular imaging and siRNA delivery.

In situ real-time investigation of cancer cell photothermolysis mediated by excited gold nanorod surface plasmons.

The photothermolysis of living EMT-6 breast tumor cells triggered by gold nanorods (AuNRs) with two-photon irradiation was conducted in situ and under real-time observation. The morphology and plasma membrane permeability of the cells were key indicators to the phenomena. AuNRs with an aspect ratio of 3.92, and a longitudinal absorption peak at 800 nm were synthesized with a seed-mediated method. The nanorods surfaces were further modified with polystyrenesulfonate (PSS) for biocompatibility. The prepared nanorods displayed excellent two-photon photoluminescence imaging. In situ real-time results revealed cavities internal to the cells were created from thermal explosions triggered by AuNRs localized photothermal effect. The cavitation dynamic is energy dependent and responsible for the perforation or sudden rupture of the plasma membrane. The energy threshold for cell therapy depended significantly on the number of nanorods taken up per cell. For an ingested AuNR cluster quantity N approximately 10-30 per cell, it is found that energy fluences E larger-than 93 mJ/cm(2) led to effective cell destruction in the crumbled form within a very short period. As for a lower energy level E = 18 mJ/cm(2) with N approximately 60-100, a non-instant, but progressive cell deterioration, is observed.

X-ray beamlines for structural studies at the NSRRC superconducting wavelength shifter.

Using a superconducting-wavelength-shifter X-ray source with a photon flux density of 10(11)-10(13) photons s(-1) mrad(-1) (0.1% bandwidth)(-1) (200 mA)(-1) in the energy range 5-35 keV, three hard X-ray beamlines, BL01A, BL01B and BL01C, have been designed and constructed at the 1.5 GeV storage ring of the National Synchrotron Radiation Research Center (NSRRC). These have been designed for structure-related research using X-ray imaging, absorption, scattering and diffraction. The branch beamline BL01A, which has an unmonochromatized beam, is suitable for phase-contrast X-ray imaging with a spatial resolution of 1 microm and an imaging efficiency of one frame per 10 ms. The main beamline BL01B has 1:1 beam focusing and a medium energy resolution of approximately 10(-3). It has been designed for small-angle X-ray scattering and transmission X-ray microscopy, used, respectively, in anomalous scattering and nanophase-contrast imaging with 30 nm spatial resolution. Finally, the branch beamline BL01C, which features collimating and focusing mirrors and a double-crystal monochromator for a high energy resolution of approximately 10(-4), has been designed for X-ray absorption spectroscopy and high-resolution powder X-ray diffraction. These instruments, providing complementary tools for studying multiphase structures, have opened up a new research trend of integrated structural study at the NSRRC, especially in biology and materials. Examples illustrating the performances of the beamlines and the instruments installed are presented.

Phosphatized polar lobe-forming embryos from the Precambrian of southwest China.

In developing embryos of some extant spiralian animals, polar lobe formation is one of the symmetry-breaking mechanisms for segregation of maternal cytoplasmic substances to certain blastomeres and not others. Polar lobe formation leads to unique early cleavage morphologies that include trilobed, J-shaped, and five-lobed structures. Fossil embryos similar to modern lobeforming embryos are recognized from the Precambrian Doushantuo Formation phosphates, Weng'an, Guizhou Province, China. These embryos are abundant and form a developmental sequence comparable to different developing stages observed in lobe-forming embryos of extant spiralians. These data imply that lobe formation is an evolutionarily ancient process of embryonic specification.

The fabrication and application of Zernike electrostatic phase plate.

The Zernike electrostatic phase plate (ZEPP) consisting of three ring electrodes and two insulating rings has been fabricated using Micro Electro-Mechanical System processes. The electrostatic field produced in the phase plate was measured by electrostatic force microscopy. The electrostatic field and focal length of the phase plate is calculated using electron optics principles. The comparison of the experimental electrostatic field and the theoretical calculated is discussed. Finally, we report the application of ZEPP to enhance contrast of the SiON(x)/SiO(2) interface in an NMOS semiconductor device. The quantitative analysis of the contrast enhancement versus the applied bias is discussed in detail.

Synchrotron radiation imaging of internal structures in live animals.

Ionizing radiation has long been used in medicine since the discovery of X-rays. Diagnostic imaging using synchrotron radiation has been under investigation since Rubenstein et al. reported dual-energy iodine-K-edge subtraction coronary angiography. Recently, computed tomography (CT) and magnetic resonance imaging (MRI) have provided better quality results than conventional radiology, providing important information on human internal structures. However, such techniques are unable to detect fine micron sized structures for the early diagnosis of tumors, vascular diseases and other medical objectives. Third generation synchrotron X-rays are well known for their superiority in coherence and energy tunability with respect to conventional X-rays. Consequently, new contrast mechanisms with a superior spatial resolution are becoming available. Here we present the extremely fine details of live animal internal structures using unmonochromatized synchrotron X-rays (white beam) and a simple detector system. Natural movements of the internal organs are also shown. The results indicate that this imaging technique can be applied to investigating microstructures and evaluating the function of the internal organs. Furthermore, this imaging system may be applied to humans as the next tool beyond CT and MRI.