Materials scientists, biologist, chemists, physicists and engineers all find a home in the Martinez laboratory. Part of the team is focused on gold and silver nanoclusters. Noble metal nanoclusters, containing a few to several hundred metal atoms with sizes ranging from sub-nanometer to ∼2 nm, constitute a special class of nanomaterial.Unlike their larger counterparts (e.g., plasmonic nanoparticles), the ultrasmall size induces strong quantum confinement effects, which leads to molecule-like properties such as discrete energy levels with sizable band gap, strong optical absorption characterized by multiple single electron transitions, and size and surface dependent photoluminescence.As a bridge between molecular materials and nanoparticles, metal nanoclusters have attracted increasing research interest and hold promising applications in optics, catalysis, and biomedicine. The Martinez group creates superlattices of clusters protected by small molecules and creation of fluorescent clusters protected by DNA. Compared to other ligands on protected metal nanoclusters, DNA-templated metal nanoclusters manifest intriguing physical and chemical properties that are heavily influenced by the design of DNA templates. For example, DNA-templated silver nanoclusters can show bright fluorescence, tunable emission colors, and enhanced stability by tuning the sequence of encapsulating DNA template. We are interested in cluster synthesis, their photophysical characterization by fluorescence correlation spectroscopy and other single-molecule techniques, and their application as cocatalysts and fluorescent probes for bioimaging and sensing.
The Martinez lab also creates soft materials and their assemblies to create materials for application in regenerative medicine to opto-electronics. One side of our group is interested in genetic encoding of polymers. Genetically encoded polymers, like their synthetic relatives, have repeating units of blocks that give the polymer its materials properties like tensile strength, moduli, etc. In particular we are interested in elastin-like polymer (ELP) where we are creating vaccine carriers, libraires of ELPS for the facile selection of active materials and ELPs that have defined optoelectronic properties.
Balog, E.R.M.+, Ghosh, K., Park, Y.-I., Hartung, V., Sista, P., Rocha, R.C., Wang, H.-L., Martinez, J.S. “Stimuli-responsive genetically engineered polymer hydrogel demonstrates emergent optical responses” ACS Biomat. Sci. & Eng.2 (7), 1135-1142(2016)
Phipps, M.L.+, Lillo, A.M., Shou Y., Schmidt, E.N., Paavola, C.D., Swanson, B.I., Bradbury, A.R.M., Martinez, J.S. “Affinity Ligands From “Helper Cell” Peptide Libraries”PLOS One 11 (9), e0160940(2016)
Chakraborty, S.+, Babanova, S., Rocha, R.C., Desireddy, A., Artyushkova, K., Atanassov, P.*, Martinez, J.S*. “A DNA-Hosted Gold Nanocluster Enhances Enzymatic Reduction of Oxygen by Facilitating Efficient Electron Transfer”J. Amer. Chem. Soc., 137(36), 11678-11687 (2015) *corresponding authors (highlighted in Science Daily, EurekaAlert, Los Alamos Daily Post, Santa Fe New Mexican, Nanotechnology News, Phys.Org, Clean Technica, Fuel Cell Works, Biofuels International).
Park, Y.-I.+,Postupna, O., Zhugayevych, A., Kyu, S.-W., Park, Y.-S., Park, B., Park, J., Martinez, J.S., Tretiak, S., Wang, H.-L. “A New pH Sensitive Fluorescent and White Emission Material through Controlled Intermolecular Charge Transfer” Chem. Sci., 6, 789 (2015)
J.K. Sharma+, M.L. Phipps, H.-C. Yeh, J.H. Werner, J.S. Martinez “Evolution of highly fluorescent silver nanocluster” Nanoscale, 4(14), 4107-4110 (2012)
S.H. Yeu, N. Abeyasinghe, M. Orr, H.-C. Yeh, J.K. Sharma, J.H. Werner, A.P. Shreve, O. Varnavski, J.S. Martinez, and T. Goodson III “Bright two-photon emission and multi-atom excitation in a DNA-templated fluorescent silver nanoclusters investigated by ultra-fast spectroscopy” Nanoscale, 4(14) 4247-4254 (2012)
Yeh, H.-C.+, Sharma, J. ,Shih, I.-M., Vu, D.M. Martinez, J.S.*, Werner, J.H.*“Colorimetric detection of single-nucleotide variations using silver nanoclusters” J. Amer. Chem. Soc., 134(28) 11550-11558 (2012) *corresponding authors (highlighted in C&EN “Silver nanoclusters spot single-base mutations in DNA” July, 2012)
ZR Stromberg, ML Phipps, HD Magurudeniya, CA Pedersen, T Rajale, …“Formulation of stabilizer-free, nontoxic PLGA and elastin-PLGA nanoparticle delivery systems” International Journal of Pharmaceutics(2021) 597, 120340
E Perillo, ML Phipps, JS Martinez, A Efimov “Femtosecond third-order sum frequency and four-wave mixing imaging” Multiscale Imaging and SpectroscopyI (2020) 11216, 1121610
Elkin, T., Copp, S.M., Hamblin, R.L., Martinez, J.S., Montaño, G.A., Rocha, R.C. “Synthesis of Terpyridine-terminated Amphiphilic Block Copolymers and their Self-assembly in to Metallopolymer Nanovesicles” Materials(2019) 12(4) 601.
Chen, Y., Phipps, M.L., Werner, J.H., Chakraborty, S., Martinez, J.S. “DNA Templated Metal Nanoclusters: From Emergent Properties to Unique Applications” Accounts of Chemical Research(2018), 51,11, 2756-2763.
Lillo, A.M., Lopez, C.L., Rajale, T., Yen, H.J., Magurudeniya, H.D., Phipps, M.L., Balog. E.R.M., Sanchez, T.C., Iyer, S., Wang, H.-L., MIchalczyk, R., Rocha, R., Martinez, J.S. “Conjugation of Amphiphilic Proteins to Hydrophobic Ligands in Organic Solvent”Bioconjugate Chemistry(2018) 29, 8, 2654-2664