Enzyme microencapsulation platform for bioelectrocatalytic systems

氧化还原酶是一种非常强大的催化剂，可以克服电化学过程的基本限制，即大多数裸电极缺乏选择性和低催化性能。为了使用这种酶作为有效的电催化剂，必须将酶置于电极表面。酶是由大自然设计的，在特定的环境中工作，如活细胞和生物液体，而不是在电极表面。固定酶的方式，保持其活性，同时允许有效的电子转移与电极代表了一个挑战，刺激了四十多年来该领域的研究（自1962年Clark和Lyons首次报道酶电极以来）。我们的研究提出使用微胶囊作为一种方法来固定酶在电极表面的生物电催化系统的发展。微胶囊化是将一种敏感剂封闭在微米范围内大小可变的中空半透性球体中。微胶囊的空心核心在水环境中含有酶，因此非常有利于保持酶的活性和稳定性。微胶囊可以由大量材料制成，其性质取决于目标应用；一种生物相容性聚合物可用于酶电极的体内应用。微胶囊可以共价结合到电极表面以实现固定化。这样，酶（包含在胶囊中）在物理上保留在表面而不降低它们的活性。通过开发生物传感器（环境和生物医学领域的监测）和生物燃料电池（微型和纳米电子设备和传感器的便携式电源），这里描述的酶固定化平台将在许多高科技领域得到应用。

Redox enzymes are very powerful catalysts to circumvent the fundamental limitations of electrochemical processes which are the lack of selectivity and low catalytic properties of most bare electrodes. In order to use such enzymes as efficient electrocatalysts, one must place the enzyme on the surface of an electrode. Enzymes were designed by Nature to work in specific environments such as living cells and biological fluids rather than on the surface of an electrode Immobilizing enzymes in a way that preserves their activity while allowing efficient electron transfer with the electrode represents a challenge that has stimulated research in this field for over forty years (since the first reported enzyme electrode by Clark and Lyons in 1962). Our research proposes the use of microencapsulation as a way to immobilize enzymes on the surface of electrodes for the development of bioelectrocatalytic systems. Microencapsulation consists in the confinement of a delicate agent in a hollow, semi-permeable sphere of variable size in the microns range. The hollow core of microcapsules contains the enzyme in an aqueous environment which is therefore very favorable to retain enzymatic activity and stability. The microcapsules can be made from a large array of materials, the nature of which depends on the targeted application; a biocompatible polymer can be used for in-vivo application of enzyme electrodes. The microcapsules can be covalently bound to the surface of electrodes to achieve immobilization. That way, the enzymes (contained in the capsules) are physically retained on the surface without decreasing their activity. The enzyme immobilization platform described here will find application in many high-technology sectors through the development of biosensors (monitoring in environmental and biomedical fields) and bio-fuel cells (portable power sources for micro and nanoelectronic devices and sensors).