This work describes the design and development process of an immunosensor. The creation of such devices goes through various steps, which complement each other, and choosing an efficient immobilization method that binds to a specific target is essential to achieve satisfactory diagnostic results. In this perspective, the emphasis here is on developing biosensors based on binding antigens/antibodies on particular surfaces of magneto-elastic sensors. Different aspects leading to the improvement of these sensors, such as the antibody structure, the chemical functionalization of the surface, and cross-linking antibody reticulation were summarized and discussed. This paper deals with the progress of magneto-elastic immunosensors to detect bacterial pathogens and associated toxins. Biologically modified surface characterization methods are further considered. Thus, research opportunities and trends of future development in these areas are finally discussed.