Fluorescent pH-Sensitive Nanoparticles in an Agarose Matrix for Imaging of Bacterial Growth and Metabolism

摘要

Bacteria distribute all over the biota and are present almost everywhere in our daily life. Some (such as Lactobacillus and Steptomyces) are beneficial to mankind. Others do more harm than good, especially in terms of food storage and health. The growth of bacteria causes enormous food spoil and—even worse—threatens food safety and the health of consumers. More than 20 % of food all over the world is being wasted because of spoilage. This waste causes economic losses, is not acceptable in times of widespread starvation, and also induces health and environmental problems. Thus, real-time monitoring of bacterial metabolism and growth is essential for food storage and also for monitoring food freshness. Optical sensors possess the unique feature of enabling imaging of parameters such as hydrogen peroxide, carbon dioxide, cations, temperature, oxygen and pH value. To enable optimal spatial resolution in case of bacteria with their typical diameters between 2 and 10 μm, it is, however, mandatory to design nanosized sensors rather than using conventional imaging sensor layers or microsized sensor particles.