This invention introduces a new class of devices for detecting the presence of biological molecules. The construction principle of the device involves the direct introduction of small monomers of macromolecules into the surface layer of a semiconductor, for example by doping at the gate-area of a field effect transistor (or any other similar suitable electronic device, also on carbon basis). There are a few biological monomers which pair specifically enough for a selective measurement, such as nucleotides (or portions thereof, e.g. adenine, thymine, guanine, cytosine and uracil). This invention leads to substantial improvement of biosensors, as there should be: Better signal to noise ratio, and options for: reading of nucleotide sequences, better process control, and new synthesis possibilities (e.g. modified Merrifield Synthesis). The invention also offers the potential to construct cybernetic systems and true biochips.