**Acknowledgements**

caused by the medium weight. With the evaporation of medium, the influence factors of weight and reflex became smaller and the signals increased again. The active signals shown by lines 3 and 4 were achieved when20µl medium with living and with dead E. coli (1.7 ×

cells/µl)was loaded into the reservoirs, respectively. The primary deflections also came from the weight and the reflex of E. coli medium, so at the loading point the active signals

**Figure 11.** The comparative signals between only medium and the medium containing living or dead E. coli[88]

For E.coli detection, the experimental results show that the conditions of E. coli can be de‐ tected based on the deflection tests. For the biological and medical applications, other kinds of cells or molecules can also be detected based on the biosensor test systems. The analysis of some pathological changes of cells or molecules can be carried out based on the alteration of membrane deflection. Furthermore, the deflection signal can be translated into electric signal though adding an electrode on the substrate, which is still promoting for portable

Labeling of biomolecules with fluorescent or other similar tags for detection can result in sample losses during the labeling and purification process and occasional loss of functionali‐ ty, especially in proteins and other small molecules. Label-free detection technique can con‐ quer the disadvantage, and the optical interference method is easy and simply to operate and high precision to detect the deflection of membrane for getting the information/proper‐ ties of the biological analytes. Label-free detection measurements of biosensors are becom‐ ing a promising alternative approach to traditional label-based methods. Surface stressbased micro membrane biosensor is a relatively new class of sensor, this kind of biosensor

103

became smaller as well.

104 State of the Art in Biosensors - General Aspects

sensitive biosensor by us.

**4. Conclusion**

This work was financially supported by the National Natural Science Foundation of China (Grant 51105267 and Grant No. 91123036) and the National Research Foundation for the Doctoral Program of Higher Education of China (Grant No.20111402120007).
