Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Potsdam, Germany.
Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Potsdam, Germany.
ACS Sens. 2023 Nov 24;8(11):4143-4151. doi: 10.1021/acssensors.3c01385. Epub 2023 Nov 7.
We demonstrate a novel, rapid, and cost-effective biosensing paradigm that is based on an in situ visualization of bacterial exoenzyme activity using biphasic Janus emulsion droplets. Sensitization of the droplets toward dominant extracellular enzymes of bacterial pathogens is realized via selective functionalization of one hemisphere of Janus droplets with enzyme-cleavable surfactants. Surfactant cleavage results in an interfacial tension increase at the respective droplet interface, which readily transduces into a microscopically detectable change of the internal droplet morphologies. A macroscopic fluorescence read-out of such morphological transitions is obtained via ratiometrically recording the angle-dependent anisotropic emission signatures of perylene-containing droplets from two different angles. The optical read-out method facilitates detection of marginal morphological responses of polydisperse droplet samples that can be easily produced in any environment. The performance of Janus droplets as powerful optical transducers and signal amplifiers is highlighted by rapid (<4 h) and cost-effective antibody and DNA-free identification of three major foodborne pathogens, with detection thresholds of below 10 CFU mL for and <10 to 10 CFU mL for and .
我们展示了一种新颖、快速且具有成本效益的生物传感范例，该范例基于使用双相反相乳液液滴原位可视化细菌外切酶活性。通过用可被酶裂解的表面活性剂选择性地功能化 Janus 液滴的一个半球，实现了对细菌病原体主要细胞外酶的敏化。表面活性剂的裂解导致相应的液滴界面处的界面张力增加，这很容易转化为内部液滴形态的微观可检测变化。通过从两个不同角度对含有苝的液滴的角度依赖性各向异性发射特征进行比率记录，获得这种形态转变的宏观荧光读出。光学读出方法有利于检测多分散液滴样品的微小形态响应，这些样品可以在任何环境中轻松制备。Janus 液滴作为强大的光学传感器和信号放大器的性能通过快速（<4 小时）和经济高效的抗体和 DNA 免费方法得到了突出体现，可用于鉴定三种主要食源性病原体，其检测限分别为 <10 CFU mL 用于 、<10 至 10 CFU mL 用于 和 。
