- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effective dielectric tensor of deformed-helix ferroelectric liquid crystals with subwavelength pitch and large tilt angle
摘要： Short pitch deformed helix ferroelectric liquid crystals have numerous applications as active materials in displays, optical telemetry, and biomedical devices. In this paper, we derive convenient analytical formulas to calculate the effective dielectric tensor of these materials beyond the space average approximation. By comparison with exact numerical calculations, we show that our formulas are remarkably accurate in predicting optical properties in virtually all practical situations, including the important case of large tilt angles, where the space average approximation breaks down. We also present a comparison between the two complementary approaches of expanding the mesoscopic dielectric tensor versus the mesoscopic transfer matrix, by deriving an expression for the effective transfer matrix as an in?nite expansion and explicitly calculating the corresponding effective dielectric tensor for the ?rst time. Our results demonstrate that both methods give accurate predictions when two-photon scattering terms are taken into account.
关键词： deformed-helix ferroelectric liquid crystals,space average approximation,effective dielectric tensor,two-photon scattering,optical properties
更新于2025-09-10 09:29:36
-
Nonlinear optical microscopy for label-freely detecting gastric intestinal metaplasia
摘要： Intestinal metaplasia has been widely considered as a precursor of gastric cancer. As a result, early detection and accurate diagnosis will have important clinical significance. Therefore, nonlinear optical microscopy using two-photon excited fluorescence combined with second harmonic generation was used for investigating gastric mucosal intestinal metaplasia in this work. The imaging results showed that this microscope has the ability to directly identify this lesion from normal tissues in the absence of labels, and to further differentiate the subtyping of intestinal metaplasia. Furthermore, nuclear areas from normal gastric mucosa and intestinal metaplasia subtypes were measured, respectively, to show the cell changes while gastric mucosa developed from normal to intestinal metaplasia. This study may provide an approach for further researching these diseases in the future, and highlights the potential of nonlinear optical microscopy as a diagnostic tool for label-free identification of gastric intestinal metaplasia.
关键词： second harmonic generation,gastric intestinal metaplasia,nonlinear optical microscopy,two-photon excited fluorescence
更新于2025-09-10 09:29:36
-
Intravitreal AAV-Delivery of Genetically Encoded Sensors Enabling Simultaneous Two-Photon Imaging and Electrophysiology of Optic Nerve Axons
摘要： Myelination of axons by oligodendrocytes is a key feature of the remarkably fast operating CNS. Oligodendrocytes not only tune axonal conduction speed but are also suggested to maintain long-term axonal integrity by providing metabolic support to the axons they ensheath. However, how myelinating oligodendrocytes impact axonal energy homeostasis remains poorly understood and difficult to investigate. Here, we provide a method of how to study electrically active myelinated axons expressing genetically encoded sensors by combining electrophysiology and two-photon imaging of acutely isolated optic nerves. We show that intravitreal adeno-associated viral (AAV) vector delivery is an efficient tool to achieve functional sensor expression in optic nerve axons, which is demonstrated by measuring axonal ATP dynamics following AAV-mediated sensor expression. This novel approach allows for fast expression of any optical sensor of interest to be studied in optic nerve axons without the need to go through the laborious process of producing new transgenic mouse lines. Viral-mediated biosensor expression in myelinated axons and the subsequent combination of nerve recordings and sensor imaging outlines a powerful method to investigate oligodendroglial support functions and to further interrogate cellular mechanisms governing axonal energy homeostasis under physiological and pathological conditions.
关键词： genetically encoded sensors,myelinated axons,intravitreal AAV injection,ATP-sensor ATeam1.03YEMK,optic nerve recording,two-photon imaging
更新于2025-09-10 09:29:36
-
Designing luminescent ruthenium prodrug for precise cancer therapy and rapid clinical diagnosis
摘要： The effective design of a targeted drug delivery system could improve the therapeutic efficacy of anticancer drugs by reducing their undesirable adsorption and toxic side effects. Here, an RGD-peptide functionalized and bioresponsive ruthenium prodrug (Ru-RGD) was designed for both cancer therapy and clinical diagnosis. This prodrug can be selectively delivered to cervical tumor sites to enhance theranostic efficacy. The benzimidazole-based ligand of the complex is susceptible to acidic conditions so, after reaching the tumor microenvironment, ligand substitution occurs and the therapeutic drug is released. The deep-red emissions produced by both one-photon and two-photon excitation increases the potential of Ru-RGD for use in the deep tissue imaging of 3D tumor spheroids. The specific accumulation of the Ru prodrug in tumor sites allows for precise tumor diagnosis and therapy in vivo. Luminescence staining of 38 clinical patient specimens shows that Ru-RGD exhibits differences in binding capability between cervical cancer and normal tissue, with a sensitivity of 95% and a specificity of 100%. This study thus provides an approach for the effective design and application of targeted metal complexes in cancer therapy and clinical diagnosis.
关键词： targeted drug delivery,cancer theranosis,rapid clinical diagnosis,two-photon imaging,tumor microenvironment
更新于2025-09-10 09:29:36
-
Phase control of plasmon enhanced two-photon photoluminescence in resonant gold nanoantennas
摘要： Plasmonic nanoantennas emit two-photon photoluminescence, which is much stronger than their second harmonic generation. Unfortunately, luminescence is an incoherent process and therefore generally not explored for nanoscale coherent control of the antenna response. Here, we demonstrate that, in resonant gold nanoantennas, the two-photon absorption process can be coherent, provided that the excitation pulse duration is shorter than the dephasing time of plasmon mode oscillation. Exploiting this coherent response, we show the pure spectral phase control of resonant gold nanoantennas, with effective read-out of the two-photon photoluminescence.
关键词： two-photon photoluminescence,gold nanoantennas,plasmonic nanoantennas,spectral phase control,coherent control
更新于2025-09-10 09:29:36
-
High Optical Energy Storage and Two-Photon Luminescence from Solution-Processed Perovskite-Polystyrene Composite Microresonators
摘要： Optical green emitting microresonators with high values of nonlinearity are desired for high optical up-conversion energy storage and lasing applications. Here we report on the synthesis of benzylammonium lead iodide (BALI) perovskite microcrystals made via anti-solvent diffusion method. The use of polystyrene (PS) matrix helps the growth of environmentally stable BALI nanocrystals as a result of polymer capping. Optimization of the ratio of BALI-PS during the self-assembly process leads to the formation of defect-free composite microspheres. Further, these BALI crystals act as an active material within the microsphere resonators that display whispering gallery modes (WGM). These WGMs are responsible for high optical storage energy of resonators evidenced by their Q-factor as high as ~1180. Two-dimensional finite difference time-domain calculation shows the concentration of the electric field near the microspheres boundary within a small mode volume of 1.83 μm3. Remarkably, BALI-PS composite microresonators and their neat crystals exhibit brilliant two-photon luminescence upon excitation by the infrared fundamental radiation. This simplistic microresonators fabrication technique provides a route towards low-cost non-linear optical microlasers and other optical energy devices useful for various applications.
关键词： non-linear optical properties,perovskite,optical microresonators,polymer microspheres,two-photon emission
更新于2025-09-10 09:29:36
-
Isomeric Effect of Mercaptobenzoic Acids on the Synthesis, Stability, and Optical Properties of Au <sub/>25</sub> (MBA) <sub/>18</sub> Nanoclusters
摘要： We report a simple size focusing, two-step “bottom-up” protocol to prepare water-soluble Au25(MBA)18 nanoclusters, using the three isomers of mercaptobenzoic acids (p/m/o-MBA) as capping ligands and Me3NBH3 as a mild reducing agent. The relative stability of the gas-phase multiply deprotonated Au25(MBA)18 ions was investigated by collision-induced dissociation. This permitted us to evaluate the possible isomeric effect on the Au?S interfacial bond stress. We also investigated their optical properties. The absorption spectra of Au25(MBA)18 isomers were very similar and showed bands at 690, 470, and 430 nm. For all Au25(MBA)18 isomeric clusters, no measurable one-photon excited fluorescence under UV?vis light was found, in neither solid- nor solution-state. The two-photon excited emission spectra and first hyperpolarizabilities of the clusters were also determined. The results are discussed in terms of the possible isomeric effect on excitations within the metal core and the possibility of charge transfer excitations from the ligands to the metal nanocluster.
关键词： Au25(MBA)18 nanoclusters,first hyperpolarizabilities,collision-induced dissociation,isomeric effect,optical properties,two-photon excited emission,mercaptobenzoic acids
更新于2025-09-10 09:29:36
-
Micro-Dumbbells—A Versatile Tool for Optical Tweezers
摘要： Manipulation of micro- and nano-sized objects with optical tweezers is a well-established, albeit still evolving technique. While many objects can be trapped directly with focused laser beam(s), for some applications indirect manipulation with tweezers-operated tools is preferred. We introduce a simple, versatile micro-tool operated with holographic optical tweezers. The 40 μm long dumbbell-shaped tool, fabricated with two-photon laser 3D photolithography has two beads for efficient optical trapping and a probing spike on one end. We demonstrate fluids viscosity measurements and vibration detection as examples of possible applications.
关键词： direct laser writing,3D lithography,optical tweezers,viscosity,two-photon polymerization,micro-tool,optical trapping
更新于2025-09-10 09:29:36
-
Visualizing Endogenous Sulfur Dioxide Derivatives in Febrile Seizure-Induced Hippocampal Damage by a Two-Photon Energy Transfer Cassette
摘要： Febrile seizure (FS), a frequently encountered seizure disorder in pediatric populations, can cause hippocampus damage. It has been elucidated that sulfur dioxide (SO2) content is overproduced during the development of FS and related brain injury. Thus, in situ monitoring the level of endogenous SO2 in FS-related models is helpful to estimate the pathogenesis of FS-induced brain injury, but effect detection method remains to be explored. Herein, we developed a two-photon energy transfer cassette based on acedan-anthocyanidin scaffold, TP-Ratio-SO2, enabling to achieve this purpose. TP-Ratio-SO2 specifically responds to SO2 derivatives (HSO3-/SO32-) in ultrafast fashion (less than 3s), and HSO3-/SO32- can be sensitively determined with a detection limit of 26 nM. Moreover, it exhibits significant changes in two well-resolved ?uorescence emission (?λ = 140 nm) by reacting with HSO3-/SO32-, behaving as a ratiometric fluorescent sensor. Importantly, ratiometric imaging of endogenous SO2 derivatives generation in hyperpyretic U251 cells and as well as in rat model of FS-treated hippocampus damage were successfully carried out by TP-Ratio-SO2, demonstrating that it may be a promising tool for studying the role of SO2 in FS-associated neurological diseases.
关键词： Two-photon fluorescence probe,Febrile seizure,Sulfur dioxide,Ratiometric imaging,Hippocampus damage
更新于2025-09-09 09:28:46
-
Automatic Graph-based Modeling of Brain Microvessels Captured with Two-Photon Microscopy
摘要： Graph models of cerebral vasculature derived from 2-photon microscopy have shown to be relevant to study brain microphysiology. Automatic graphing of these microvessels remain problematic due to the vascular network complexity and 2-photon sensitivity limitations with depth. In this work, we propose a fully automatic processing pipeline to address this issue. The modeling scheme consists of a fully-convolution neural network to segment microvessels, a 3D surface model generator and a geometry contraction algorithm to produce graphical models with a single connected component. Quantitative assessment using NetMets metrics, at a tolerance of 60 μm, false negative and false positive geometric error rates are 3.8% and 4.2%, respectively, whereas false negative and false positive topological error rates are 6.1% and 4.5%, respectively. Our qualitative evaluation confirms the efficiency of our scheme in generating useful and accurate graphical models.
关键词： segmentation,graph,Cerebral microvasculature,deep learning,convolution neural networks,two-photon microscopy
更新于2025-09-09 09:28:46