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碳点-纳米凝胶复合物（PNIPAM-CDs）如何合成？基于增强现实视觉刺激的脑机接口又是什么？如何在芯片上实现模拟血脑屏障？

本期线上博士领航活动为大家邀请到了三位澳门大阳城集团2138网站的博士，将通过文献领读的方式来给大家解答这几个问题。

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赵晨

随着科学技术的发展，越来越多的药物和治疗方法被应用于癌症治疗，即使如此，癌症依然是威胁人类生命健康的主要疾病之一。因此，开发全新的抗肿瘤治疗方法，有效提升治疗效率，提高治疗的靶向性逐渐发展成为该领域的研究热点。碳点作为新型荧光纳米材料，近些年来在生物医学领域中有着广泛的应用。目前报道的碳点治疗功能有限，且无法在肿瘤部位有效累积，容易通过肾脏清除的方式快速排出体外，最终影响治疗效果。因此，开发兼具成像及多模式治疗功能的碳点，提升其协同治疗效率，并通过简便复合的方式提高其在肿瘤部位的有效累积十分必要。

博士生赵晨报道了一种具有程序化刺激响应性的碳点-纳米凝胶复合物（PNIPAM-CDs）。PNIPAM-CDs具有以下特点：（1）开发了碳点的深红色荧光、光声成像能力、光热和光动力治疗功能；(2)与单独的碳点相比，碳点与纳米凝胶的复合物由于粒径增大，生物相容性提高，血液循环时间更长，更有利于材料在肿瘤部位的累积；(3)PNIPAM-CDs可以通过单波长的激光照射触发光热和光动力治疗效果，不仅可以诱导癌细胞凋亡，而且可以减小复合物的粒径，促进功能成分在肿瘤部位的深度渗透；(4)通过PNIPAM-CDs的pH响应电荷翻转和温度依赖性亲水/疏水转换能力增强材料被细胞的摄取；（5）由于谷胱甘肽（GSH）的过表达，部分降解的PNIPAM-CDs进入肿瘤细胞后会发生进一步的裂解，这有利于它们从体内快速清除。这些特性使PNIPAM-CDs成为优异的程序化荧光/光声成像引导的光热/光动力协同肿瘤治疗纳米平台。

相关研究成果以“Programmed Stimuli-Responsive Carbon Dot-Nanogel Hybrids for Imaging-Guided Enhanced Tumor Phototherapy”为题发表在 ACS Applied Materials & Interfaces 上。

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刘思宇

Objective:Brain machine interfaces (BMIs) interpret human intent into machine reaction, while visual stimulation(VS) paradigm is one of the most wildly used approach on this aspect. Although VS based BMIs perform relatively high information transfer rate (ITR), it is still hard for BMIs’ subject to control machines in dynamic environment(for example, catching a moving object or targeting a walking person). In this study, we utilized a brain machine interface based on augmented reality (AR) visual stimulation (AR-VS), the proposed visual stimulation was dynamically generated based on machine vision, and the human intent was interpreted by dynamic decision time interval(DTI) approach. A robot based on the coordination of task and self-motion (CTS) system was controlled by the proposed paradigm in a fast and flexible state.

Methods: Objects in scene was firstly recognized and tracked by machine vision. AR-VS was generated based on neural network recognition and light stream tracking. The number and distribution of visual stimulation was confirmed by recognized objects. Electroencephalogram (EEG) features corresponding to VS and human intent was collected by dry-electrode EEG cap, and figured out by filter bank canonical correlation analysis(fb-CCA) method. Key parameters in the AR-VS, including the effect of VS size, frequency, dynamic object moving speed, ITR and the performance of BMI controlled robot was analyzed, respectively.

Conclusion&Significance: the online accuracy and ITR of the proposed AR-VS paradigm over 9 healthy subjects were 92±5% and 36.3±20.1bits/min within 6 dynamic targets. In online robot control experiment, Brain controlled hybrid tasks including self-moving and grabbing objects was achieved 64% faster than traditional SSVEP paradigm.  The proposed paradigm based on AR-VS could be optimized and adopted in other kinds of VS based BMIs, such as P-300, omitted stimulus potential(OSP), and Miniature Event Related Potential  (Miniature-ERPs) paradigm, and better result in dynamic environment.

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闫然然

Studies of neonatal neural pathologies and development of appropriate therapeutics are hampered by a lack of relevant in vitro models of neonatal blood-brain barrier (BBB). To establish such a model, we have developed a novel blood-brain barrier on a chip (B3C) that comprises a tissue compartment and vascular channels placed side-by-side mimicking the three-dimensional morphology, size and flow characteristics of microvessels in vivo. Rat brain endothelial cells (RBEC) isolated from neonatal rats were seeded in the vascular channels of B3C and maintained under shear flow conditions, while neonatal rat astrocytes were cultured under static conditions in the tissue compartment of the B3C. RBEC formed continuous endothelial lining with a central lumen along the length of the vascular channels of B3C and exhibited tight junction formation, as measured by the expression of zonula occludens-1 (ZO-1). ZO-1 expression significantly increased with shear flow in the vascular channels and with the presence of astrocyte conditioned medium (ACM) or astrocytes cultured in the tissue compartment. Consistent with in vivo BBB, B3C allowed endfeet-like astrocyte-endothelial cell interactions through a porous interface that separates the tissue compartment containing cultured astrocytes from the cultured RBEC in the vascular channels. The permeability of fluorescent 40 kDa dextran from vascular channel to the tissue compartment significantly decreased when RBEC were cultured in the presence of astrocytes or ACM (from 41.0±0.9 x 10−6 cm/s to 2.9±1.0 x 10−6 cm/s or 1.1±0.4 x 10−6 cm/s, respectively). Measurement of electrical resistance in B3C further supports that the addition of ACM significantly improves the barrier function in neonatal RBEC. Moreover, B3C exhibits significantly improved barrier characteristics compared to the transwell model and B3C permeability was not significantly different from the in vivo BBB permeability in neonatal rats. In summary, we developed a first dynamic in vitro neonatal BBB on a chip (B3C) that closely mimics the in vivo microenvironment, offers the flexibility of real time analysis, and is suitable for studies of BBB function as well as screening of novel therapeutics.

时间：2022年5月8日（周日）上午10:00

地点：腾讯会议：871-932-940

会议链接：

https://meeting.tencent.com/dm/OlSaswn41Cou