Image 1 of 1 Pro Bi-Est + Quicksilver Scientific $40.00 Nanoemulsified topical serum using estriol and estradiol derived from phytosterols, natural compounds used to synthesize bioidentical estrogens. Add To Cart Added! Nanoemulsified topical serum using estriol and estradiol derived from phytosterols, natural compounds used to synthesize bioidentical estrogens.