Life time ( m s)

1. Detection of Isozymes by Polymerized LiposomesSanku Mallik (North Dakota State University)DMR 0705767 Chemically differentiating enzymes which catalyze the same reaction is very challenging. Usually biological antibodies are used to structurally differentiate such enzymes. In contrast to the marked similarity of the active sites, the distribution of solvent-exposed amino acid residues are different for these enzymes. Fluorescent probes which interact with the surface pattern of amino acids can be used to distinguish between closely-related enzymes, without the use of sensitive biological antibodies. We have demonstrated the proof-of-concept for this principle by employing the recombinant human carbonic anhydrases as the model isozymes and polymerized liposome-incorporated Eu3+ ions as the luminescent probes. Life time (ms) Lanthanide luminescence lifetimes of polymerized liposome incorporated Eu3+ ions for different isozymes of carbonic anhydrases.

2. Detection of Isozymes by Polymerized LiposomesSanku Mallik (North Dakota State University) DMR 0705767 • Broader Impacts: • NDSU has started a summer internship program with Mississippi Valley State University (MVSU, an undergraduate institution in Itta Bena, MS). An Afro-American undergraduate student (Edna Lampkin) is working under Mallik’s supervision this summer. She will graduate from MVSU in 2009. She is also being mentored to enroll in the Graduate Program of the Pharmaceutical Sciences Department at NDSU following her graduation from MVSU. • Mallik has set-up collaborative and materials transfer agreements with Abiomed Inc. (Danvers, MA). The collaboration will explore the use of the luminescent polymerized liposomes developed by Mallik in detecting high shear flow in Abiomed’s artificial hearts.

3. Detection of Isozymes by Polymerized LiposomesSanku Mallik (North Dakota State University),DMR 0705767 Composition of the liposomes: Liposomes were prepared in 25 mM HEPES buffer, pH = 7.0 with total lipid concentration of 1 mg/mL. The liposomes were extruded through 100 nm membranes and then photo-polymerized. The structures of the lipids used in the liposomes are shown below. Lipid 1 is commercially available; the other lipids were synthesized in Mallik’s laboratory. Elegbede et al., J. Chem. Soc. Chem. Comm.2007, 4495 – 4498.