The invention relates to a dextran functionalized by at least one hydrophobic alpha-amino acid radical, said alpha-amino acid being grafted or bonded to the dextran by a bonding arm and a functional group. The tremolo assembly consists of in addition to the base mounting plate, an adjustable spring tension block, extension springs, a string anchor bar, a cross member attachment bar, eyebolts, hex nuts, flat head machine screws, shoulder screws, flat washers, set screws, adhesive backed felt, and a tremolo arm. The connections may be direct or indirect. The body is formed with a first surface and a second surface which are opposite to each other, and includes a terminal mounting hole penetrating through the first surface and the second surface.