The present invention relates to a bifunctional material which comprises copper and which is capable of storing nitric oxide (NO), as well as catalytically producing nitric oxide from a suitable precursor. The material typically includes a zeolite and the copper may be part of, or separate from the zeolite. In this manner the material may include a single bifunctional material； that is, a material which is capable of both storing NO and catalytically producing NO, such as Cu-MFI or Cu-X. Alternatively the material may include at least two components, a first component to store NO, such as a zeolite Zn-LTA, and a further component including Cu(I), such as Cu2O, to catalytically produce NO from a suitable precursor. The bifunctional material may be used in a pharmaceutical, neutraceutical or cosmetic preparation, or comprised in a medical article, a cosmetic and/or personal hygiene product.
