The chemical structure of the dicyanogen photopolymer (CN)x, also known as paracyanogen, prepared in different solvents from dicyanogen (CN)2 photopolymerization under the action of ultraviolet light, is shown to be very similar to the polymer derived from hydrogen cyanide (HCN) and from certain tholins obtained from a simulated Jovian atmosphere. The implications of dicyanogen and its polymer as a precursor of some organic molecules already detected in cometary comas and tails and in meteorites are discussed. In particular, paracyanogen may be present in the cometary nuclei and in the surface of certain low-albedo objects in the Solar system.

This article is based on the Outstanding Young Investigator Award presentation given by Kristi S. Anseth at the 2001 MRS Spring Meeting on April 17, 2001, in San Francisco. Anseth was recognized for “innovative work in polymeric biomaterials for drug delivery, bone and cartilage repair, and tissue engineering, and for outstanding leadership potential in this interdisciplinary field of materials research.”

Photopolymerization provides many advantages as a technique for the fabrication of biomaterials. Temporal and spatial control, along with the diversity in material properties found with photopolymerizable materials, are advantageous in the biomaterials industry. For instance, multifunctional anhydride monomers form highly cross-linked surface-eroding networks directly in bone defects. These networks have good mechanical properties that are maintained with degradation and have the potential to restore tissue-like properties to bone during the healing process. Additionally, cartilage-forming cells photoencapsulated in hydrogel networks secrete an extracellular matrix as the hydrogel is resorbed and may provide a treatment alternative for cartilage defects that do not heal spontaneously. Finally, transdermal polymerization (photopolymerization through the skin) of multifunctional monomers is a noninvasive technique that is being developed for tissue regeneration and wound-healing applications.