嗅觉和味觉图象传感技术的研究进展

本文介绍了嗅觉和味觉图象传感技术的基本原理、嗅觉和味觉图象传感器的研制，介绍了表面光伏技术ＳＰＴ及半导体技术在嗅觉和味觉图象传感器中的应用，阐述了这种化学图象检测方法一些独特的优点和它在人工嗅觉和味觉及其它生物化学传感技术方面的应用，最后本文简要地讨论了基于化学图象的一些信息处理和模式识别方法以及这种新技术的发展前景。     

嗅觉和味觉图象传感技术的研究进展

本文介绍了嗅觉和味觉图象传感技术的基本原理、嗅觉和味觉图象传感器的研制。介绍了表面光伏技术ＳＰＴ（ＳｕｒｆａｃｅＰｈｏｔｏｖｏｌｔａｇｅＴｅｃｈｎｏｌｏｇｙ）及半导体技术在嗅觉和味觉图象传感器中的应用，阐述了这种化学图象检测方法一些独特的优点和它在人工嗅觉和味觉及其它生物化学传感技术方面的应用。最后本文简要地讨论了基于化学图象的一些信息处理和模式识别方法以及这种新技术的发展前景。     

仿生嗅觉与味觉传感技术及其应用的研究进展

动物的化学感受系统具有惊人的能力,能够在极低的浓度下识别数千种分子结构各异的化学物质,其灵敏性、选择性和响应速度都远高于当前的人工识别系统.近年来,研究者致力于利用完善的天然分子识别机制,开发出一种与传统嗅觉/味觉传感器相比更具仿生意义的新型化学探测系统,即仿生嗅觉/味觉传感器.仿生嗅觉/味觉传感器通常将动物嗅觉味觉的受体、细胞和组织作为敏感材料,然后使用多种人工检测方法,如光学、电化学和声波检测器件等,实现对化学物质的检测和识别.文中概述了动物嗅觉/味觉感受系统对化学物质的信息处理机制,并结合本实验室的工作,综述了目前仿生嗅觉/味觉传感器的常用技术及其未来发展趋势,并展望了其在医疗、工业和军事等领域的应用前景.     

仿生嗅觉神经芯片的研究进展

嗅觉神经芯片是在电子鼻和细胞传感器研究的基础上，在芯片表面培养嗅觉感受神经元所构成的一种神经芯片。该技术是通过用微电极阵列等芯片技术记录气体分子作用于神经元膜表面嗅觉受体产生的动作电位而达到气体检测的一种更具仿生意义的生物电子鼻技术。在嗅觉生物学研究的基础上对嗅觉芯片的研究进行了综合论述，重点介绍了嗅觉细胞的培养和神经芯片技术等嗅觉芯片相关技术的研究进展。并对该领域的应用前景进行了展望。     

味觉电生理建模和仿真的研究进展

味质的结构和化学多样性决定了味觉有基于不同味觉物质的多种传导机制。近年来，随着分子生物学、细胞电生理研究方法的发展，有关味觉受体细胞电生理特性、味觉传导机制及味觉编码的研究取得了很大进展。综述了目前国际上味觉受体细胞电生理特性及其建模仿真方法的研究进展，同时评述目前味觉电生理建模仿真的几种主要方法的特点，最后论述了建模仿真方法对味觉机理以及味觉临床病理学研究的重要意义。     

仿生嗅觉神经芯片的研究进展

嗅觉神经芯片是在电子鼻和细胞传感器研究的基础上,在芯片表面培养嗅觉感受神经元所构成的一种神经芯片。该技术是通过用微电极阵列等芯片技术记录气体分子作用于神经元膜表面嗅觉受体产生的动作电位而达到气体检测的一种更具仿生意义的生物电子鼻技术。在嗅觉生物学研究的基础上对嗅觉芯片的研究进行了综合论述,重点介绍了嗅觉细胞的培养和神经芯片技术等嗅觉芯片相关技术的研究进展。并对该领域的应用前景进行了展望。     

人工味觉及其模式识别

本文探讨了生物味觉的机理，研究了模拟生物味觉构造的人工味觉系统和用于对味觉物质敏感的生物类脂材料的特性、选择性及用生物类脂材料构成的多通道电极阵列式味觉传感器。针对基本的五种味觉物质，给出了有关测试结果以及一些有意义的结论。实验表明，上述方案可用于开发一种实用的新型味觉传感系统     

基于BIOMEMS技术的细胞电阻抗传感器的研究进展

细胞一电阻抗传感器是基于BIOMEMS技术的研究细胞电生理和临床药理研究的新兴工具,主要应用于细胞等微生物体的形态和功能研究.近年来,它以其新颖简单的设计和长时程的无损测试等优点一直受到国内外学者和企业的广泛关注.首先分析细胞一电极阻抗界面模型并加以细化,然后介绍生物阻抗传感器在国际上研究的最新进展.在此基础上,结合实验室当前的研究工作,介绍了自制的基于叉指型细胞电阻抗传感器,最后提出了未来主要发展方向.     

基于细胞三维受控组装技术的细胞芯片构建

如何将细胞准确装配于细胞芯片的设计位置,是制约细胞芯片向组织和生理系统细胞芯片方向发展的关键问题之一。本研究用细胞组装技术将细胞装配到细胞芯片的设计位置并检测的理论和方法。首先设计构建了含多组传感器阵列的细胞芯片;选取输送和固定细胞的明胶-海藻酸钠复合水凝胶材料,探讨用细胞组装技术在芯片上精确装配细胞的方法;测试复合材料和多种电解溶液对电阻抗的影响,并用芯片对细胞增殖进行检测。结果显示:复合材料能输送并将细胞固定在芯片上超过4周;细胞组装技术可精确将细胞装配到指定传感器,组装的细胞/材料微丝直径100～120μm。复合材料对芯片基础电阻抗影响小,在大于103Hz的高频段,基础阻抗为小于102.6Ω;PBS和DMEM溶液在103.5～105Hz高频段可替代氰铁化钾溶液作为电解液;芯片上的传感器在103.5Hz可准确测出Hela细胞增殖引起的电阻抗变化。研究证明了用细胞组装技术构建复杂细胞芯片的可行性。     

基于LAPS芯片的味觉感受细胞敏感和传导的研究

味觉感受细胞为味觉感受器,表达了酸、甜、苦、咸和鲜味感受受体或离子通道。在味质刺激下,味觉感受细胞发放动作电位并释放神经递质。其时域放电模式编码了味觉信息。最常用的膜片钳技术不利于对味觉细胞的时域放电进行长期无损记录。本研究利用LAPS芯片,对味质刺激下味觉细胞的胞外电位进行无损的长时程记录。另外,利用LAP芯片可寻址的优点,在芯片表面沉积对5-HT敏感的PVC膜,对味觉组织在味质刺激下释放的神经递质5-HT进行测量。实验结果发现,不同类型的味觉细胞对相应味质刺激的响应是可以区分开的,且味觉组织在酸或苦甜鲜刺激下,有神经递质5-HT释放。另外,LAPS芯片为味觉细胞的味觉敏感和传导的研究提供了一种新的方法。     

Gustation as a factor in the ingestion of sweet and fat emulsions by the rat

This paper was written to pay honor to Professor Gerard P. Smith because of his strong influence on me to study the ingestion of sweet and fat mixtures. Three experiments are reported here, in which the laboratory rat was given an emulsion of a glucose+saccharin mixture with corn oil. In the first experiment, a two-bottle, 24-h test was given comparing the emulsion with water. Over 6 weeks, the concentration of the corn oil was gradually increased. When given only food and water, or the glucose/saccharin solution, the rats regulated their caloric intake and grew at a normal rate. In contrast, when the corn oil was present, the rats significantly increased their caloric intake, resulting in a marked increase in body weight. In the second experiment, a detailed analysis of the ingestion revealed that the rate of licking the emulsion during drinking bouts increased in a linear manner as the concentration of the corn oil was increased. In the third experiment, a conditioned taste aversion to the sweet/fat emulsion generalized to the fat more than to the sweet solutions. The implications for a gustatory input are discussed.     

A study of olfaction and gustatory senses in sheep after olfactory bulbectomy

The importance of taste and smell in discrimination of sodium salts was examined in normal and anosmic sheep. To test for anosmia, faeces of pig, calf and sheep were used as noxious odours. Intact sheep, and sheep with one olfactory bulb removed avoided the aversive stimulus whereas following total bulbectomy, the faecal odour was no longer a deterrent. Olfactory bulbectomy did not affect food intake but changes in fluid intake, urinary loss and electrolyte excretion were apparent. In two-choice preference tests, normal sheep showed a marked aversion for 0.48 M NaHCO3 and 0.51 M NaCl when compared to water. Following either unilateral or bilateral olfactory bulbectomy the aversion for sodium salts persisted but was less extreme. This suggests that in the final discrimination of sodium salts the sense of taste is dominant but olfaction or the olfactory bulb may have a minor role.     

Effects of olfactory and gustatory stimuli on neural excitability for swallowing

This project evaluated the effects of olfactory and gustatory stimuli on the amplitude and latency of motor-evoked potentials (MEPs) from the submental muscles when evoked by transcranial magnetic stimulation (TMS). Sixteen healthy volunteers (8 males; age range 19-43) participated in the study. Lemon concentrate at 100% and diluted in water to 25% were presented separately as odor and tastant stimuli. Tap water was used as control. 15 trials of TMS-evoked MEPs triggered by volitional contraction of the submental muscles and volitional swallowing were measured at baseline, during control condition, during stimulus presentation, and immediately, 30-, 60-, and 90-min poststimulation for each of the four stimulus presentations. Experiments were repeated using the combined odor and tastant concentrations that most influenced the MEP independently. Differences in MEP amplitude measured during swallowing were seen at 30-, 60-, and 90-min poststimulation for simultaneous olfactory and gustatory stimulation as opposed to no differences seen at any point for stimuli presented separately. This study has shown that combined odor and tastant stimulation (i.e., flavor) can increase MEP amplitude during swallowing and that this enhancement of MEP can persist for at least 90 min following stimulation. As increased MEP amplitude has been associated with improved swallowing performance, a follow-up study is underway to determine the biomechanical changes produced by altered MEPs to facilitate translation of these data to clinical dysphagia management.     

钙黏素超家族的研究进展

钙黏素是一类介导Ca~(2 )依赖的细胞间黏附的跨膜糖蛋白,主要参与同型细胞间的黏附作用,可与质膜下细胞骨架系统相结合或与信号传导系统相联系,直接或间接影响细胞的活动,参与很多生物学过程,包括细胞识别、细胞骨架排列、细胞增殖、分化、细胞黏附、细胞迁移以及信号传导等。在调节胚胎发育、机体形态发生等方面具有重要作用。钙黏素家族成员的异常表达可能与多种遗传疾病相关。     

现代电子技术对神经电生理学研究的推动

电子信息科学、计算机科学和生物医学工程等学科的飞速发展,对神经电生理实验手段起到了巨大的推动作用.长期以来神经电生理的研究手段是记录麻醉动物的单神经元放电活动.当今,现代先进技术能用长期植入的细胞外电极同时记录清醒、活动动物大量神经元,从而对神经电生理的研究起到了巨大的推动作用.本文就近阶段神经电生理学研究技术进展状况作一综述.     

磁性纳米线的制备及在生物传感器中的应用研究进展

磁性纳米线除了具有表面效应、量子尺寸效应、体积效应和宏观量子隧道效应等优异的纳米特性,更具有特异的磁学性能,尤其是多层纳米线的巨磁电阻效应,使其在生物医学领域具有广阔的应用前景。综述了目前阶段磁性纳米线的常规制备方法——模板合成法,包括高分子模板、多孔阳极氧化铝模板、碳纳米管模板等几种常用模板,以及磁性纳米线在模板中的...     

Olfaction in the psychosis prodrome: Electrophysiological and behavioral measures of odor detection

Smell identification deficits (SIDs) are relatively specific to schizophrenia and its negative symptoms, and may predict transition to psychosis in clinical high-risk (CHR) individuals. Moreover, event-related potentials (ERPs) to odors are reduced in schizophrenia. This study examined whether CHR patients show SIDs and abnormal olfactory N1 and P2 potentials. ERPs (49 channels) were recorded from 21 CHR and 20 healthy participants (13 males/group; ages 13–27 years) during an odor detection task using three concentrations of hydrogen sulfide (H₂S) or blank air presented unilaterally by a constant-flow olfactometer. Neuronal generator patterns underlying olfactory ERPs were identified and measured by principal components analysis (unrestricted Varimax) of reference-free current source densities (CSD). Replicating previous findings, CSD waveforms to H₂S stimuli were characterized by an early N1 sink (345 ms, lateral–temporal) and a late P2 source (600 ms, mid-frontocentroparietal). N1 and P2 varied monotonically with odor intensity (strong > medium > weak) and did not differ across groups. Patients and controls also showed comparable odor detection and had normal odor identification and thresholds (Sniffin' Sticks). However, olfactory ERPs strongly reflected differences in odor intensity and detection in controls, but these associations were substantially weaker in patients. Moreover, severity of negative symptoms in patients was associated with reduced olfactory ERPs and poorer odor detection, identification and thresholds. Three patients who developed psychosis had poorer odor detection and thresholds, and marked reductions of N1 and P2. Thus, despite the lack of overall group differences, olfactory measures may be of utility in predicting transition to psychosis among CHR patients.     

单核苷酸多态性分析技术的应用及其最新进展

单核苷酸多态性（single nucleotide polymorphisms, SNPs）技术既可用于包括多基因遗传病在内的疾病相关基因的定位，又能够满足基因连锁、突变评估和生物遗传进化的研究，是继限制性酶切片断长度多态分析（restriction fragment length polymorphism, RFLP）和微卫星多态分析（micro-satellite polymorphism）之后的又一新的遗传多态性分析技术，具有广泛的应用前景。本文对SNPs的特点方法及其最新进展进行综述。     

Hypoxia-induced therapeutic neovascularization in a mouse model of an ischemic limb using cell aggregates composed of HUVECs and cbMSCs

Cell transplantation for therapeutic neovascularization holds great promise for treating ischemic diseases. This work prepared three-dimensional aggregates of human umbilical vein endothelial cells (HUVECs) and cord-blood mesenchymal stem cells (cbMSCs) with different levels of internal hypoxia by a methylcellulose hydrogel system. We found that few apoptosis occurred in these cell aggregates, despite developing a hypoxic microenvironment in their inner cores. Via effectively switching on the hypoxia-inducible factor-1α-dependent angiogenic mechanisms, culturing the internally hypoxic HUVEC/cbMSC aggregates on Matrigel resulted in formation of extensive and persistent tubular networks and significant upregulation of pro-angiogenic genes. As the level of internal hypoxia created in cell aggregates increased, the robustness of the tubular structures developed on Matrigel increased, and expression levels of the pro-angiogenic genes also elevated. Transplantation of hypoxic HUVEC/cbMSC aggregates into a mouse model of an ischemic limb significantly promoted formation of functional vessels, improved regional blood perfusion, and attenuated muscle atrophy and bone losses, thereby rescuing tissue degeneration. Notably, their therapeutic efficacy was clearly dependent upon the level of internal hypoxia established in cell aggregates. These analytical results demonstrate that by establishing a hypoxic environment in HUVEC/cbMSC aggregates, their potential for therapeutic neovascularization can be markedly enhanced.     

The neuropeptides CCK and NPY and the changing view of cell-to-cell communication in the taste bud

The evolving view of the taste bud increasingly suggests that it operates as a complex signal processing unit. A number of neurotransmitters and neuropeptides and their corresponding receptors are now known to be expressed in subsets of taste receptor cells in the mammalian bud. These expression patterns set up hard-wired cell-to-cell communication pathways whose exact physiological roles still remain obscure. As occurs in other cellular systems, it is likely that neuropeptides are co-expressed with neurotransmitters and function as neuromodulators. Several neuropeptides have been identified in taste receptor cells including cholecystokinin (CCK), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and glucagon-like peptide 1 (GLP-1). Of these, CCK and NPY are the best studied. These two peptides are co-expressed in the same presynaptic cells; however, their postsynaptic actions are both divergent and antagonistic. CCK and its receptor, the CCK-1 subtype, are expressed in the same subset of taste receptor cells and the autocrine activation of these cells produces a number of excitatory physiological actions. Further, most of these cells are responsive to bitter stimuli. On the other hand, NPY and its receptor, the NPY-1 subtype, are expressed in different cells. NPY, acting in a paracrine fashion on NPY-1 receptors, results in inhibitory actions on the cell. Preliminary evidence suggests the NPY-1 receptor expressing cell co-expresses T1R3, a member of the T1R family of G-protein coupled receptors thought to be important in detection of sweet and umami stimuli. Thus the neuropeptide expressing cells co-express CCK, NPY, and CCK-1 receptor. Neuropeptides released from these cells during bitter stimulation may work in concert to both modulate the excitation of bitter-sensitive taste receptor cells while concurrently inhibiting sweet-sensitive cells. This modulatory process is similar to the phenomenon of lateral inhibition that occurs in other sensory systems.