A eficiência da microscopia de força atômica no desenvolvimento de biossensores

Abstract

Today, diagnostic methods are an essential part of disease treatment and patient healing. In order to carry them out, the use of sophisticated techniques is necessary. The emergence of biosensors as equipment capable of performing such a function has revolutionised not only the way medical procedures have been carried out over the years, but also plays a key role in the quality of life of individuals who need a quick and accurate diagnosis. Biosensors can receive different classifications, depending on their transducer or biological element; from these points their main objective can be defined. One can find today electrochemical, magnetic, piezoelectric, thermal, resonance and optical biosensors. Even with such a variation of tools, the demand for greater accuracy and sensitivity continues to drive the ongoing development of other techniques. The present work used atomic force microscopy to develop a biosensor (nano immunosensor), capable of measuring antigen-antibody interactions, using as targets the Bovine Serum Albumin (BSA) and Anti-BSA, immobilized by means of the surface functionalization technique called Silanization and subsequently performing force curve measurements with the AFM equipment. The tests showed that there are significant differences in the interaction of the non-functionalised sensor tip in contact with the also non-functionalised substrate and of the adhesion force on functionalised surfaces. Not only the strength presented different values, but the shape of the curve showed steps of the interaction between antigen and antibody. The data collected were compared to the existing literature and demonstrated that there was an effective antigen-antibody interaction.