The progress of olfactory transduction and biomimetic olfactory-based biosensors

Olfaction is a very important sensation for all animals. Recently great progress has been made in the research of olfactory transduction. Especially the novel finding of the gene superfamily encoding olfactory receptors has led to rapid advances in olfactory transduction. These advances also promoted the research of biomimetic olfactory-based biosensors and some obvious achievements have been obtained due to their potential commercial prospects and promising industrial applications. This paper briefly introduces the biological basis of olfaction, summarizes the progress of olfactory signal transduction in the olfactory neuron, the olfactory bulb and the olfactory cortex, outlines the latest devel- opments and applications of biomimetic olfactory-based biosensors. Finally, the olfactory biosensor based on light addressable potentiometric sensor (LAPS) is addressed in detail based on our recent work and the research trends of olfactory biosensors in future are discussed.     

揭开嗅觉之奥秘

简要介绍了2004年诺贝尔生理学或医学奖得主和获奖成就,并阐述了嗅觉与生活和体育运动的密切关系.     

Mice cloned from olfactory sensory neurons

Cloning by nuclear transplantation has been successfully carried out in various mammals, including mice. Until now mice have not been cloned from post-mitotic cells such as neurons. Here, we have generated fertile mouse clones derived by transferring the nuclei of post-mitotic, olfactory sensory neurons into oocytes. These results indicate that the genome of a post-mitotic, terminally differentiated neuron can re-enter the cell cycle and be reprogrammed to a state of totipotency after nuclear transfer. Moreover, the pattern of odorant receptor gene expression and the organization of odorant receptor genes in cloned mice was indistinguishable from wild-type animals, indicating that irreversible changes to the DNA of olfactory neurons do not accompany receptor gene choice.     

Olfaction: mosquito receptor for human-sweat odorant

Female Anopheles mosquitoes, the world's most important vector of Plasmodium falciparum malaria, locate their human hosts primarily through olfactory cues, but the molecular mechanisms that underlie this recognition are a mystery. Here we show that the Anopheles gambiae protein AgOr1, a female-specific member of a family of putative odorant receptors, responds to a component of human sweat. Compounds designed to activate or block receptors of this type could function as attractants for trapping mosquitoes or as insect repellents in helping to control Anopheles and other insect pests.     

嗅蛋白对铕纳米颗粒荧光增强效应的研究

以单宁酸做还原剂,在表面活性剂十二烷基苯磺酸钠（sodium dodecylbenzene sulfonate,SDBS）形成的微乳环境中将硝酸铕还原成铕（europium,Eu）纳米颗粒,通过修饰剂硫辛酸与嗅蛋白结合,分析铕纳米颗粒结合嗅蛋白前后的荧光变化与嗅蛋白含量的关系及机制。结果发现铕纳米颗粒与嗅蛋白结合后荧光强度明显增强,在优化条件下,荧光强度与嗅蛋白的浓度在0.020～8.0mg/L范围内呈良好的线性关系,检出限为0.012mg/L,对5.0mg/L 嗅蛋白进行11次平行测定,其相对标准偏差为2.4%。嗅蛋白主要通过分子间能量转移使铕纳米颗粒的荧光强度增强,利用该变化测定嗅蛋白含量,结果灵敏、准确,令人满意。     

A single population of olfactory sensory neurons mediates an innate avoidance behaviour in Drosophila

All animals exhibit innate behaviours in response to specific sensory stimuli that are likely to result from the activation of developmentally programmed neural circuits. Here we observe that Drosophila exhibit robust avoidance to odours released by stressed flies. Gas chromatography and mass spectrometry identifies one component of this 'Drosophila stress odorant (dSO)' as CO2. CO2 elicits avoidance behaviour, at levels as low as 0.1%. We used two-photon imaging with the Ca2+-sensitive fluorescent protein G-CaMP to map the primary sensory neurons governing avoidance to CO2. CO2 activates only a single glomerulus in the antennal lobe, the V glomerulus; moreover, this glomerulus is not activated by any of 26 other odorants tested. Inhibition of synaptic transmission in sensory neurons that innervate the V glomerulus, using a temperature-sensitive Shibire gene (Shi(ts)), blocks the avoidance response to CO2. Inhibition of synaptic release in the vast majority of other olfactory receptor neurons has no effect on this behaviour. These data demonstrate that the activation of a single population of sensory neurons innervating one glomerulus is responsible for an innate avoidance behaviour in Drosophila.     

基于Gabor纹理增强的人脸活体检测算法

针对人脸信息认证系统中存在的欺骗攻击问题,利用色彩空间转换信息丢失的特性,提出一种人脸活体检测算法。通过Gabor滤波器组多尺度、多方向地增强关键人脸图像纹理特征,抑制人脸图像的一般特征。高斯径向基函数分类器分类SURF(speeded up robust features)算子提取特征描述子,区分人脸活体与非法用户的欺骗攻击。利用类间方差衡量特征改进前后的可分性,计算图像原始特征与纹理增强后特征的类间方差、类内方差大小以及可分性判据J。在公开数据集Replay-Attack,CASIA-FASD数据库进行测试,彩色纹理图像增强后,人脸关键特征被增强而一般特征被抑制,背景与目标的类间方差增大,类内方差减小,特征可分性增强从而更具鲁棒性,使得纹理细节能被有效利用。实验结果表明,该算法能有效、实时地判断人脸活体与欺骗攻击。     

A high-sensitive detection method for carvone odor by implanted electrodes in rat olfactory bulb

Mammalian olfactory systems have extraordi- nary ability to sense and identify various trace odorants. Taking advantages of cell culture and micro-fabrication technologies, olfactory cell- or tissue-based biosensor represent a promising platform for in vitro odorant detec- tion. However, in vitro conditions lead to shortened cell/ tissue survivals, and the working life of neuron chips is short. The purpose of this study is to develop an in vivo recording and analyzing method for long-term and repeatable detection of odor stimulation. In this study, we implanted penetrating micro-wire array electrode into the olfactory bulb of conscious rats to obtain odor-evoked electrophysiological activities. Then, we investigated the response of ensembles of mitral/tufted cells to stimulation with carvone at a number of concentrations in time and frequency domains. The stable, repeatable odorant responses from up to 16 neural regions could be obtained for at least 3 weeks. Further, we explored the concentration detection sensitivity limitation of developed method, and found the detection low limit of carvone was below 10-a~ mol/L. The result demonstrates that the concentra- tion range of in vivo odorant detection method is much wider than in vitro method.     

纳米金生物传感器的制备及其在汞离子检测中应用

基于T-Hg²⁺-T结构,在纳米金修饰电极(AuNPs/Au)表面构建了一种灵敏检测Hg²⁺的电化学生物传感器.首先,在金(Au)表面电沉积AuNPs作为基底,增加ssDNA的引入量,50℃下硫堇(Th)依靠T和Hg²⁺的特异性结合迅速嵌入ssDNA双螺旋内部,基于插入的电化学信号测定Hg²⁺.在最佳条件下,传感器对Hg²⁺检测的线性范围为10～100 nmol·L^-1,检出限低至7.4 nmol·L^-1.传感器展现出良好的选择性.     

基于高频加强变换的焊接缺陷检测方法

根据X射线线阵实时成像检测压力容器的特点,提出焊缝图像处理及快速发现焊接缺陷的方法。利用自适应中值滤波方法和类间、类内方差比分割法及数学形态学方法对原始焊缝图像进行降噪和提取焊缝区域,并对提取的焊缝内部进行频域锐化的高频加强变换.仿真结果表明,自适应中值滤波能够有效去除噪声,并保持焊缝和缺陷的边缘细节;类间、类内方差比分割方法增强了图像目标与背景的对比,与数学形态学方法并用能准确地提取焊缝区域;高频加强变换能够为焊缝缺陷提供清晰的视觉效果,从而根据其显示的特点对焊接缺陷进行提取.     

银纳米颗粒溶胶表面增强红外基底对低浓度福美双农药的快速检测

采用水热法制备了一种银纳米颗粒溶胶,通过乙醇洗涤后得到银纳米颗粒表面增强红外基底,用于检测低浓度福美双农药。结果表明,该增强基底可检测低至10^-7mol/L的福美双农药,且不同浓度下福美双溶液的表面增强红外光谱强度呈现良好的线性关系,该基底对福美双分子的红外光谱增强能力高达150倍。银纳米颗粒的富集作用、电荷转移机制和电磁增强机制的共同作用使福美双的红外光谱得到显著增强。     

基于一种新模糊增强算子的图像边缘检测算法

借鉴广义模糊集的特性,提出了一种新的模糊边缘检测算法:利用一个简单的隶属度函数将空域图像转换到[0,1]的普通模糊域;然后通过一个简单的增强算子先将其扩展到[-1,2];由于一般情况下物体域(物体内部区域)主要以高灰度为主,背景域(物体背景区域)主要以低灰度为主,而过渡域(物体边缘区域)则以高梯度为主,本算法目的是对图像进行边缘检测,先不对它进行转换或截断,而将其转换到图像准灰度域,相当于把图像的物体域和背景域放到了[0,255]的区域以外;然后采用"min"或"max"算子进行所谓的边缘提取,最后将提取的"边缘"数据进行截断处理,从而将图像数据转换到图像的空间域,即图像的灰度域。从边缘检测结果来看,本算法更适合于低对比度、含有较精细部分以及纹理丰富的图像检测,且耗时较小。     

Conditional modulation of spike-timing-dependent plasticity for olfactory learning

Mushroom bodies are a well-known site for associative learning in insects. Yet the precise mechanisms that underlie plasticity there and ensure their specificity remain elusive. In locusts, the synapses between the intrinsic mushroom body neurons and their postsynaptic targets obey a Hebbian spike-timing-dependent plasticity (STDP) rule. Although this property homeostatically regulates the timing of mushroom body output, its potential role in associative learning is unknown. Here we show in vivo that pre-post pairing causing STDP can, when followed by the local delivery of a reinforcement-mediating neuromodulator, specify the synapses that will undergo an associative change. At these synapses, and there only, the change is a transformation of the STDP rule itself. These results illustrate the multiple actions of STDP, including a role in associative learning, despite potential temporal dissociation between the pairings that specify synaptic modification and the delivery of reinforcement-mediating neuromodulator signals.     

光学生物传感器的医学应用及进展

本文介绍了光纤生物传感器、椭偏光学生物传感器、纳米级PEBBLE传感器三种光学生物传感器的发展及在医学上的应用情况,并讨论了光学生物传感器的研究进展.     

光学生物传感器的医学应用及进展

本文介绍了光纤生物传感器、椭偏光学生物传感器、纳米级PEBBLE传感器三种光学生物传感器的发展及在医学上的应用情况,并讨论了光学生物传感器的研究进展.     

Applications of polymer single nanochannels in biosensors

There are many elaborate masterpieces exist in natural world. Learning from nature, people developed serial intelligent biomimetic devices. Biomimetic smart nanochannels received widespread attention for mimicking biological processes in bodies. Excellent stability, tailorable surface characteristics and nano-size effects rend polymer single nanochannel an ideal candidate for constructing sensitive and reproducible biosensors. Nanochannels are responsive for special analytes while appropriate recognition elements are modified in channels wall. In this review, we summarized recent works in contructing biosensors that are using polymer single nanochannels for detecting various analytes.     

光学生物传感器的医学应用及进展

本文介绍了光纤生物传感器、椭偏光学生物传感器、纳米级PEBBLE传感器三种光学生物传感器的发展及在医学上的应用情况,并讨论了光学生物传感器的研究进展。