Bulk optical components are conventionally used to control light. However, bulk optical components are limited by optical loss and ability for miniaturization. To address this problem, we developed soft multimaterial photonic devices. The theoretical predictions and experimental results are compared with the device characterization. Plasmonic super-resolution imaging based on this device is presented as an example. We find the result of plasmonic super-resolution imaging enabled by the compact design is comparable to commercial devices.
A vision system is a critical element to develop the driver assistance systems for improved mobility, semi-automated or fully automated driving functions, and enhancing safety. However, vision systems in the developing autonomous vehicles have been plagued by poor visibility conditions caused by glare. We demonstrate a miniaturized integrative electrical polarizer system allowing for rapid correction of multimodal glare to reveal hidden objects. We show our method enables classification of glare, fast response time and adaptability to multimodal glare.
Actin, as microfilaments in the cytoskeleton, is essential biological structure and mechanical properties for cell migration and division. These processes require new probes for visualization of actin. Fluorescent labeling as a traditional method accompanies photo bleaching and formation of free radicals that are harmful for live cells, resulting to hardly find a balance between more signals of observation and less light exposure. Here, we present new nanoparticle probes for continuous visualization of actin. We demonstrate continuous imaging of different cell division phases to reveal actin biological and mechanical properties.
Cell migration is an essential cellular process that help cells to develop complex organisms, organs, and tissues, arrange cells into specialized architecture and help organize the nervous system. Nanoscale imaging has the potential to provide new insight into the mechanics of cell migration. However, quantification over time in nanoscale imaging remains difficult. Here, we visualize cell migration by non-bleaching nanoscale imaging. We present a set of quantitative metrics - length, branching, gaps, distribution, and curvature - to quantitatively analyze cell migration at the nanoscale over time.
The method of delivery is considered to be one of the significant hurdles for CRISPR technologies. Conventional delivery of CRISPR by viral vectors are subject to their immunogenicity. Non-viral vectors methods are preferable but are limited by their biocompatibility and precision. Nano-plasmonic particles have shown great potential as noninvasive and spatiotemporally controllable vehicles for biomacromolecule delivery. Hereby, as a safe and precise way to delivery of CRISPR, we propose a remote optically manipulating method based on gold nanorods carrier. We have characterized gold nano-plasmonic carriers on single particle level by imaging spectroscopy. Then we have demonstrated the precise manipulation of individual nano plasmonic carriers on cells using optical trapping system. Lastly, the biocompatibility of the method is shown.
The distribution and morphology of cortical actin filaments are essential in cell dynamics, such as cell division. In this work, we propose a plasmonic approach for long term imaging to study the specifications of actin dynamics in live cells. Here, we employ a new imaging setup which can acquire a set of images with spatial sparsity. Long-term and super-resolution imaging can be achieved by our imaging setup. We demonstrate examples of different morphologies of cortical actin filaments during cell division.
CRISPR-Cas9 is an efficient and reliable tool to cleave targeted portions of DNA. Once the DNA been cut by the tool, genes are ready to be cut, inserted or modified as desired. Conventionally, CRISPR is carried by a virus into cells. However, potential safety issues exists, as the cell can physiologically respond to viral invasion, or its genome can be inserted with unwanted virus genes. Here, we show that gold nanoparticles serves as preferable successful vectors of CRISPR-Cas9, with extra benefit to allow stable imaging. This toxicity-free alternative method avoids the aforementioned issues and introduces the CRISPR-Cas9 complex safely
Fluorescence super-resolution imaging relies on fluorophores as contrast agents. As a result of the inevitable photobleaching and thus a limited photon budget, they put fundamental limitations on the temporal resolution. We propose non-bleaching, plasmonic nanoparticles as non-bleaching contrast agents with an unlimited photon budget such that both the temporal and spatial resolution can be pursued at the same time. We demonstrated a continuous observation of fine structural features in resolved actin networks. We believe the non-bleaching nanoscale imaging will open new doors for observing biological processes on a much longer timescales with higher spatial and temporal details.
Actin dynamics plays an important role in cell activities and drives a large range of cellular process such as cell division and cell motility. To visualize the actin dynamics, we introduce non-bleaching nanoscale imaging to capture actin dynamics over long time scales. Here, we demonstrate the high resolution quantification of actin dynamics by non-bleaching nanoscale imaging for the purpose of revealing resulting mechanical properties. Through this method, we visualized and quantified actin twisting dynamics through disassembly process by actin binding proteins.
CRISPR-Cas9 is a gene editing tool which has promise for the treatment and prevention of many complex diseases. Together with a short guide RNA, CRISPR-Cas9 can recognize and cut the corresponding DNA at a targeted location. Viruses are traditionally used as carriers of CRISPR-Cas9 into target cells. However, viruses may cause
immunogenic complications. Alternatively, gold nanoparticles can be utilized as carriers of CRISPR-Cas9.
Gold nanoparticles in the near infrared regime exhibit unique optical properties. In this work, we show gold nanoparticles can be stably and efficiently crosslinked to the CRISPR complex.These alternative carriers are toxicity free to and allow effective and efficient introduction of the CRISPR system.
Plasmonic nanoparticles are excellent nonbleaching probes for bio-imaging. Due to their anisotropic properties, polarization analysis of individual nanoparticles allows for revealing orientational information, plasmon mode assignment, and the local microenvironment. Previous implementations utilize mechanical rotation of conventional polarizers to align the polarization angles with specific axes of nanoparticles. However, the manufacturing defects of the polarizer (e.g., non-parallelism) limit the measurement stability (e.g., beam wobbling) in polarimetric imaging, while the mechanical rotation limits the measurement speed, and thus hinders accurate, real-time acquisition of individual nanoparticles.
Here, we demonstrate a high-speed nano-polarimetric system for stable plasmonic bio-imaging by integrating our voltage-tunable polarizer (VTP) into a microscope. The angular rotation of the polarization (0∼π) can be realized by applying voltage on the VTP. We show that our voltage-tunable system offers high extinction ratio (∼up to 250), and uniform transmission (∼55%) over a large input power range (<5% deviation for input power from 50 μW to ∼20 mW). Meanwhile, the transmission polarization can be rapidly tuned with a response time up to 50 ms. Compared to conventional polarizers, our system is able to provide reproducible and high-speed polarimetric images of individual nanoparticles with sub-pixel spatial precision. Such a polarimetric nanoimaging system could be a useful tool for real-time single nanoparticle bio-imaging with both high stability and time resolution.
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