@article{ortiz_zoellner_hong_jo_wang_liu_maggard_wang_2017, title={Harnessing Hot Electrons from Near IR Light for Hydrogen Production Using Pt-End-Capped-AuNRs}, volume={9}, ISSN={["1944-8244"]}, DOI={10.1021/acsami.7b05064}, abstractNote={Gold nanorods show great potential in harvesting natural sunlight and generating hot charge carriers that can be employed to produce electrical or chemical energies. We show that photochemical reduction of Pt(IV) to Pt metal mainly takes place at the ends of gold nanorods (AuNRs), suggesting photon-induced hot electrons are localized in a time-averaged manner at AuNR ends. To use these hot electrons efficiently, a novel synthetic method to selectively overgrow Pt at the ends of AuNRs has been developed. These Pt-end-capped AuNRs show relatively high activity for the production of hydrogen gas using artificial white light, natural sunlight, and more importantly, near IR light at 976 nm. Tuning of the surface plasmon resonance (SPR) wavelength of AuNRs changes the hydrogen gas production rate, indicating that SPR is involved in hot electron generation and photoreduction of hydrogen ions. This study shows that gold nanorods are excellent for converting low-energy photons into high-energy hot electrons, which can be used to drive chemical reactions at their surfaces.}, number={31}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Ortiz, Nathalia and Zoellner, Brandon and Hong, Soung Joung and Jo, Yue and Wang, Tao and Liu, Yang and Maggard, Paul A. and Wang, Gufeng}, year={2017}, month={Aug}, pages={25962–25969} }
 @article{liu_franzen_2008, title={Factors determining the efficacy of nuclear delivery of antisense oligonucleotides by gold nanoparticles}, volume={19}, ISSN={["1520-4812"]}, DOI={10.1021/bc700421u}, abstractNote={The present study investigates the applicability of nanoparticle delivery vectors for two-stage targeting that involves both cell entry by endocytosis and nuclear targeting using viral peptide signals. A nanoparticle vector consists of four components: a carrier nanoparticle, a stabilizer, targeting peptides, and a therapeutic cargo. Extensive study of bovine serum albumin (BSA)-peptide stabilized nanoparticle conjugates demonstrated limitations of these systems due to colloidal instability when oligonucleotides and multiple peptides were attached to the BSA protein. We found that the widely used protein streptavidin (SA) was an appropriate alternative to BSA for cell-targeting experiments. Targeting peptides and gene splicing oligonucleotides were attached to SA-nanoparticles using biotin labels. The present study uses a gene-splicing assay as a test for oligonucleotide delivery to the cell nucleus. Successful modification of gene splicing by an antisense oligonucleotide indicates that the latter must have crossed the plasma membrane, entered the nucleus, found the target sequence in the newly transcribed pre-mRNA, and hybridized to it in the spliceosome strongly enough to displace the splicing factors designed to interact with the target sequence. Targeting nanoparticles that carry gene-splicing oligonucleotides were compared with a control experiment that used lipofectamine (LF). While enhanced activity was observed in the control experiment, in the presence of LF, no gene splicing was observed for the nanoparticle targeting vectors without LF. We conclude that sequestration of cargo from the harsh conditions of the endosome is a desirable strategy for cell-targeting nanoparticles.}, number={5}, journal={BIOCONJUGATE CHEMISTRY}, author={Liu, Yanli and Franzen, Stefan}, year={2008}, month={May}, pages={1009–1016} }
 @article{liu_shipton_ryan_kaufman_franzen_feldheim_2007, title={Synthesis, stability, and cellular internalization of gold nanoparticles containing mixed peptide-poly(ethylene glycol) monolayers}, volume={79}, ISSN={["0003-2700"]}, DOI={10.1021/ac061578f}, abstractNote={Gold nanoparticles have shown great promise as therapeutics, therapeutic delivery vectors, and intracellular imaging agents. For many biomedical applications, selective cell and nuclear targeting are desirable, and these remain a significant practical challenge in the use of nanoparticles in vivo. This challenge is being addressed by the incorporation of cell-targeting peptides or antibodies onto the nanoparticle surface, modifications that frequently compromise nanoparticle stability in high ionic strength biological media. We describe herein the assembly of poly(ethylene glycol) (PEG) and mixed peptide/PEG monolayers on gold nanoparticle surfaces. The stability of the resulting bioconjugates in high ionic strength media was characterized as a function of nanoparticle size, PEG length, and monolayer composition. In total, three different thiol-modified PEGs (average molecular weight (MW), 900, 1500, and 5000 g mol-1), four particle diameters (10, 20, 30, and 60 nm), and two cell-targeting peptides were explored. We found that nanoparticle stability increased with increasing PEG length, decreasing nanoparticle diameter, and increasing PEG mole fraction. The order of assembly also played a role in nanoparticle stability. Mixed monolayers prepared via the sequential addition of PEG followed by peptide were more stable than particles prepared via simultaneous co-adsorption. Finally, the ability of nanoparticles modified with mixed PEG/RME (RME = receptor-mediated endocytosis) peptide monolayers to target the cytoplasm of HeLa cells was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). Although it was anticipated that the MW 5000 g mol-1 PEG would sterically block peptides from access to the cell membrane compared to the MW 900 PEG, nanoparticles modified with mixed peptide/PEG 5000 monolayers were internalized as efficiently as nanoparticles containing mixed peptide/PEG 900 monolayers. These studies can provide useful cues in the assembly of stable peptide/gold nanoparticle bioconjugates capable of being internalized into cells.}, number={6}, journal={ANALYTICAL CHEMISTRY}, author={Liu, Yanli and Shipton, Mathew K. and Ryan, Joseph and Kaufman, Eric D. and Franzen, Stefan and Feldheim, Daniel L.}, year={2007}, month={Mar}, pages={2221–2229} }
 @article{tkachenko_xie_liu_coleman_ryan_glomm_shipton_franzen_feldheim_2004, title={Cellular trajectories of peptide-modified gold particle complexes: Comparison of nuclear localization signals and peptide transduction domains}, volume={15}, ISSN={["1520-4812"]}, DOI={10.1021/bc034189q}, abstractNote={Gold nanoparticles modified with nuclear localization peptides were synthesized and evaluated for their subcellular distribution in HeLa human cervical epithelium cells, 3T3/NIH murine fibroblastoma cells, and HepG2 human hepatocarcinoma cells. Video-enhanced color differential interference contrast microscopy and transmission electron microscopy indicated that transport of nanoparticles into the cytoplasm and nucleus depends on peptide sequence and cell line. Recently, the ability of certain peptides, called protein transduction domains (PTDs), to transclocate cell and nuclear membranes in a receptor- and temperature-independent manner has been questioned (see for example, Lundberg, M.; Wikstrom, S.; Johansson, M. (2003) Mol. Ther. 8, 143−150). We have evaluated the cellular trajectory of gold nanoparticles carrying the PTD from HIV Tat protein. Our observations were that (1) the conjugates did not enter the nucleus of 3T3/NIH or HepG2 cells, and (2) cellular uptake of Tat PTD peptide−gold nanoparticle conjugates was temperature dependent, suggesting an endosomal pathway of uptake. Gold nanoparticles modified with the adenovirus nuclear localization signal and the integrin binding domain also entered cells via an energy-dependent mechanism, but in contrast to the Tat PTD, these signals triggered nuclear uptake of nanoparticles in HeLa and HepG2 cell lines.}, number={3}, journal={BIOCONJUGATE CHEMISTRY}, author={Tkachenko, AG and Xie, H and Liu, YL and Coleman, D and Ryan, J and Glomm, WR and Shipton, MK and Franzen, S and Feldheim, DL}, year={2004}, pages={482–490} }