Molecular Lego of knots

Trefoil, Savoy, or simple ... how do you fashion a "molecular" knot that has one of these shapes? Or better still, what are the most suitable "building blocks" for enabling the knot to assemble itself? A team of scientists has studied and catalogued the shapes that molecular building blocks should have so as to be able to assemble spontaneously into knots having specific forms, each with a possible utility in nanotechnology.