Polymethylsiloxane polyhydrate (PMSPH) is used as enterosorbent for a couple of decades (nowadays under the trademark "Enterosgel"), intended for binding in the gastrointestinal tract and excretion of toxic substances of various nature, agents that can cause diseases and metabolites. Approximate matrix composition (2D) per micell looks like this:
Pharmacodynamics shows that PMSPH effectively bounds endogenous and exogenous toxic substances of various nature, including bacteria and bacterial toxins, antigens, food allergens, drugs and poisons, heavy metal salts, alcohol, metabolic products of the body (bilirubin, urea, cholesterol and lipid complexes).
What makes this gel so selective towards the adsorption of toxins only? Why nutrients (carbohydrates, fats, amino acids, vitamins) are mostly preserved and can be assimilated by the human body regardless?
I suspect it might have something to do with the pore size and geometry, involving a docking-alike behavior, but I don't have a solid enough background in biochemistry to prove it right or wrong. Manufacturer puts a warning "Protect from freezing!", so it might also have to do with the precisely controlled pore size (which is imminently changed after solidification of trapped water).