生物传感器法测定麦芽汁中赖氨酸含量的研究

本研究利用固定化赖氨酸氧化酶和生物传感器,建立了麦芽汁中赖氨酸含量的测定方法。研究了该方法的线性范围、检出限、最适pH值范围、稳定性及专一性。以大生产麦芽汁为样品,与其它检测方法进行了比较。结果表明,生物传感器法测定赖氨酸含量操作简单而准确,加标回收率为97．41％～103．23％,RSD为2．23％;线性范围为2～100 mg/100 mL,检出限为2 mg/100 mL;稳定性及专一性强,不受其他氨基酸的干扰,能够用于氨基酸种类复杂的麦汁赖氨酸的检测。本方法与氨基酸分析仪、DBL、HPLC等方法相比较,测定结果无显著差异（P＞0．05）。     

葡萄糖传感器在微囊化动物细胞灌注培养过程中的应用

本文提出了用葡萄糖传感器监测在灌注培养微囊化动物细胞时,培液中葡萄糖量的变化。实验过程中,葡萄糖传感器的线性检测范围为１０－５００ｍｇ／１０ｍｌ．将葡萄糖氧化酶膜贮存于４℃条件下的０．０５ｍｏｌ／Ｌ ＰＢＳ（ｐＨ７．０）中,它的活力在４０天之内保持不变,本方法操作简便,灵敏度高,耗时少,准确可靠。     

Biomarker-responsive engineered probiotic diagnoses,records, and ameliorates inflammatory bowel disease in mice

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Bioluminescent monitoring of turbulent bioconvection.

Under adjusted experimental conditions, open-to-air cultures of lux gene-engineered Ralstonia eutropha (wholecell biosensors of copper) exhibit bioconvection, which accounts for fluctuating bioluminescence. The power spectrum of bioluminescence intensity fluctuations recorded from a cylindrical sample 9 mm in diameter and approximately 10 mm in height is characterized by a dominant low-frequency oscillation (with a characteristic period of approximately 8-12 min), which is occasionally accompanied by a few weaker oscillations. The corresponding spectral peaks emerge on a high-noise background. The spectra of bioluminescence intensity fluctuations qualitatively resemble the spectra of temperature or fluid velocity fluctuations in an appropriate turbulent thermal convection system. It has been suggested that in a bioconvective system, like in thermal convection systems, the emergence of oscillation reflects the large-scale convective circulation that spans the height of the cylindrical cell. The velocity of large-scale bioconvective circulation was estimated to be 37-48 microm/s. The occasional emergence of weaker-than-dominant oscillations was explained through the coexistence and interaction of the large-scale circulation with, presumably, a gene-expression-related cyclic process (with a characteristic period of approximately 25-50 min).     

Fish scales as Biosensors for Catecholamines

Certain fish scales contain specialized cells (chromatophores) with pigment granulas, which can be dispersed or aggregated in the cells. The degree of aggregation is determined by a transmitter substance, nonadrenaline, released by the sympathetic nerve endings in the skin. Isolated scales from, for example, cuckoo wrasse (Labrus ossifagus) retain a large sensitivity to externally applied nonadrenaline (or more generally catecholamines) for several weeks. The degree of aggregation in isolated scales can be measured objectively by simple photometric techniques. We demonstrate in this paper how fish scales can be used to monitor catecholamine levels in human blood plasma. A discussion of other potential biosensor applications of this intact biological receptor-effector system is also given.     

综述与专论: 基于核酸适配体传感器的即时检测（POCT）技术

即时检测（point-of-care testing，POCT）是一种检测成本低、检测速度快、准确度高、能自我采样获得临床诊断结果的新型诊断技术。该技术在临床诊断、病情监控与疫情防控等领域发挥了重要作用。核酸适配体是一种能够特异性识别多种靶标的分子探针，具有易合成、批间差异小、易实现信号放大等突出优势，是生物医学传感器中重要的分子识别元件。本文概述了核酸适配体探针的现有筛选方法和进展，总结了核酸适配体POCT传感器信号放大策略，着重介绍了各类核酸适配体传感器在POCT领域的应用现状，并对核酸适配体POCT传感器的发展前景进行了展望。     

构建冻干无细胞生物传感器快速检测临床铜绿假单胞菌感染北大核心

【目的】铜绿假单胞菌(Pseudomonas aeruginosa)是常见于医院感染的条件致病革兰氏阴性细菌,其群体感应信号3-氧代十二烷酰基高丝氨酸内酯(3-oxo-dodecanoyl-homoserine lactone,3OC12-HSL)可作为铜绿假单胞菌感染的生物标志物。本研究期望开发针对3OC12-HSL的冻干无细胞生物传感器,以实现临床铜绿假单胞菌感染的快速诊断。【方法】首先构建报告质粒以重建3OC12-HSL的应答过程,而后将该质粒加入冻干无细胞表达系统中以实现生物传感器的制备;接着利用梯度浓度的3OC12-HSL表征该传感器的灵敏度与动力学特征,并测试其底物特异性;最后通过临床样本测试验证其效果,并优化临床样本的预处理方法。【结果】本研究构建的冻干无细胞生物传感器能够在60 min内实现对临床呼吸道样本中铜绿假单胞菌感染的诊断,具有高灵敏度和高特异性。【结论】本研究构建了针对3OC12-HSL的冻干无细胞生物传感器,并借助RNase抑制蛋白预表达的策略提升了其对体液样本的耐受性,最终证明其具备开发成临床铜绿假单胞菌感染的快速检测方法的潜力。     

Development of bifunctional biosensors for sensing and dynamic control of glycolysis flux in metabolic engineering

Glycolysis is the primary metabolic pathway in all living organisms. Maintaining the balance of glycolysis flux and biosynthetic pathways is the crucial matter involved in the microbial cell factory. Few regulation systems can address the issue of metabolic flux imbalance in glycolysis. Here, we designed and constructed a bifunctional glycolysis flux biosensor that can dynamically regulate glycolysis flux for overproduction of desired biochemicals. A series of positive-and negative-response biosensors were created and modified for varied thresholds and dynamic ranges. These engineered glycolysis flux biosensors were verified to be able to characterize in vivo fructose-1,6-diphosphate concentration. Subsequently, the biosensors were applied for fine-tuning glycolysis flux to effectively balance the biosynthesis of two chemicals: mevalonate and N-acetylglucosamine. A glycolysis flux-dynamically controlled Escherichia coli strain achieved a 111.3 g/L mevalonate titer in a 1L fermenter.     

基于纳米酶的比色生物传感器在生物医学检测中的应用

比色生物传感技术由于具有灵敏度高、方法简单并且容易操作等优点，已广泛应用于生物环境中污染物检测、生物体内重要标志物的检测以及癌症筛查等多个领域。基于纳米酶的比色生物传感器主要是借助纳米酶自身所具有的催化能力，模拟类过氧化物酶活性，将显色剂氧化生成有色溶液，从而实现可视化检测，并通过对有色溶液吸光度的检测得到相关物质的含量。与无纳米酶的比色生物传感器相比，基于纳米酶的比色生物传感器具有选择性更高、检测更快以及灵敏度更高等优点。纳米酶在具有天然酶活性的同时还具有成本低、稳定性好的、易于合成等优点，其相关研究越来越广泛。目前，基于纳米酶的比色生物传感器已成为辅助相关医学检测的重要方法，同时也广泛应用于便携和实时性相关检测当中，为医学检测提供了重要的支持和保障。为了提高比色生物传感器的灵敏度以及应用范围，研究人员也在致力于增加可检测物质的种类以及纳米酶种类的多样化等。本文主要介绍基于纳米酶的比色生物传感器的检测原理、几类典型的纳米酶，以及基于纳米酶的比色生物传感器在生物医学检测领域中的应用情况和研究进展。