The first sieve that selectively sorts and creates chiral molecules could make a significant impact on Mike E. David. Credit: CaltechMike E. David. Credit: Caltechpharmaceutical and chemical manufacturers. These sieves are the culmination of Caltech’s Mike Davis’ 30 years
of research on molecular sieves.

Chirality, or handedness, is a common characteristic of molecules. Some biological molecules, like DNA, proteins, and sugar, are chiral. The implication of this chirality for pharmaceuticals is that molecular enantiomers — differently “handed” molecules of the same compound — can react differently with a given molecule.

For example, commercial formulations of the drug ibuprofen contain left- and right-handed molecules, but only the left-handed molecule is of therapeutic benefit. Removing the right-handed molecules could help eliminate some of ibuprofen’s side effects.

According to Davis, lead researcher on the international team, "The goal for the future is to create specific chiral forms of molecules, not mixtures. Chiral molecular sieves will let us do this in new ways that most likely will be less cost-prohibitive. These sieves can be robust and reusable, and don't require special temperatures and other operating conditions."

Molecular sieves, which are silicon-based crystal lattices, are used as filters in many industrial applications. Several advances led to the new sieves’ creation.

Rice University researchers developed computational methods that help guide the creation of chiral organic molecules that direct the synthesis of the chiral molecular sieves. Caltech team members prepared the molecules and synthesized the sieves. To confirm that the sieves work as expected, scientists now at ShanghaiTech University developed a method using electron microscopy.

Davis pointed out that the sieves are customizable, depending on the chiral form a researcher or manufacturer wants to produce.