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Whole mount zebrafish antibody staining (ABS) is a common staining technique used to localize protein information in a zebrafish embryo or larva. Like most biological assays, the whole mount zebrafish ABS is still largely conducted manually through labor intensive and time-consuming steps which affect both consistency and throughput of the assay. In this work, we develop a milli fluidic device that can automatically trap and immobilize the fixed chorion-less zebrafish embryos for the whole mount ABS. With just a single loading step, the zebrafish embryos can be trapped by the milli fluidic device through a chaotic hydrodynamic trapping process. Moreover, a consistent body orientation (i.e., head point inward) for the trapped zebrafish embryos can be achieved without additional orientation adjustment device. Furthermore, we employed a consumer-grade SLA 3D printer assisted method for device prototyping which is ideal for labs with limited budgets. Notably, the milli fluidic device has enabled the optimization and successful implementation of whole mount zebrafish Caspase-3 ABS. We demonstrated our device can accelerate the overall procedure by reducing at least 50% of washing time in the standard well-plate-based manual procedure. Also, the consistency is improved, and manual steps are reduced using the milli fluidic device. This work fills the gap in the milli fluidic application for whole mount zebrafish immunohistochemistry. We hope the device can be accepted by the zebrafish community and be used for other types of whole mount zebrafish ABS procedures or expanded to more complicated in situ hybridization (ISH) procedure.

Fluorescence lifetime imaging has been a powerful tool for biomedical research. Recently, fluorescence lifetime‐based multiplexing imaging has expanded imaging channels by using probes that harbor the same spectral channels and distinct excited state lifetime. While it is desirable to control the excited state lifetime of any given fluorescent probes, the rational control of fluorescence lifetimes remains a challenge. Herein, we chose boron dipyrromethene (BODIPY) as a model system and provided chemical strategies to regulate the fluorescence lifetime of its derivatives with varying spectral features. We find electronegativity of structural substituents at the 8′ and 5′ positions is important to control the lifetime for the green‐emitting and red‐emitting BODIPY scaffolds. Mechanistically, such influences are exerted via the photo‐induced electron transfer and the intramolecular charge transfer processes for the 8′ and 5′ positions of BODIPY, respectively. Based on these principles, we have generated a group of BODIPY probes that enable imaging experiments to separate multiple targets using fluorescence lifetime as a signal. In addition to BODIPY, we envision modulation of electronegativity of chemical substituents could serve as a feasible strategy to achieve rational control of fluorescence lifetime for a variety of small molecule fluorophores. [ABSTRACT FROM AUTHOR]

In order to solve the problems of the difficulty of determining the principal stiffness directions of industrial robots due to asymmetric structures and mode coupling chatters occurred in robotic milling processes caused by poor rigidly, a stiffness orientation method was proposed. Moreover, the stability of milling processes was improved by controlling the robot functional redundancy and optimizing the posture. Firstly, the stiffness ellipsoid in Cartesian coordinate system at the end of industrial robots was calculated to determine robotic principal stiffness directions in the cutting planes. Then, the stability criterion of mode coupling chatters was obtained by establishing the dynamics model of the machining system. Further, based on the stiffness orientation method, a posture optimi-zation algorithm was proposed for robotic milling. Cutting experiments confirm that stability in robotic milling along the given trajectory may be guaranteed through the optimization of industrial robot configurations without changing other parameters. [ABSTRACT FROM AUTHOR]

Molecular rotor‐based fluorophores (RBFs) have been widely used in many fields. However, the lack of control of their viscosity sensitivity limits their application. Herein, this problem is resolved by chemically installing extended π‐rich alternating carbon‐carbon linkages between the rotational electron donors and acceptors of RBFs. The data reveal that the length of the linkage strongly influences the viscosity sensitivity, likely resulting from varying height of the energy barriers between the fluorescent planar and the dark twisted configurations. Three RBF derivatives that span a wide range of viscosity sensitivities were designed. These RBFs demonstrated, through a dual‐color imaging strategy, that they can differentiate misfolded protein oligomers and insoluble aggregates, both in test tubes and live cells. Beyond RBFs, it is envisioned that this chemical mechanism might be generally applicable to a wide range of photoisomerizable and aggregation‐induced emission fluorophores. [ABSTRACT FROM AUTHOR]