Bioluminescent enzymatic biosensors: ways to manage their characteristics

Enzymatic biosensors have been lately gaining popularity in various areas of human life, from medicine to agriculture, owing to their effectiveness and selectivity towards the tested substances. Bioluminescent enzymatic biosensors attract special attention because of the light produced by the enzyme reaction. Researchers designing bioluminescent enzymatic sensors face a number of challenges, mainly associated with the low stability and/or sensitivity of the enzymes used as a biological recognition element of the biosensor. Herein we describe strategies of improving the analytical performance of bioluminescent enzymatic biosensors based on luciferase enzymes. We, first, discuss the increase in biosensors' sensitivity by optimizing the composition of the biological recognition element, including enzyme and substrate variations and addition of nanoparticles or stabilizing agents. Then, we provide insights into improving the stability of luciferases by immobilization or by the presence of chaperones and via directed mutagenesis. And the last section deals with projections for the future. We give special consideration to results of using these approaches in developing biosensors based on bioluminescent enzyme systems of fireflies and bacteria. Yet, the approaches described in the review are universal and can be effectively used to develop other enzymatic biosensors.