Publications by authors named "Lance T Dockery"

3 Publications

  • Page 1 of 1

Set of Highly Stable Amine- and Carboxylate-Terminated Dendronized Au Nanoparticles with Dense Coating and Nontoxic Mixed-Dendronized Form.

Langmuir 2019 03 18;35(9):3391-3403. Epub 2019 Feb 18.

Department of Chemistry and Biochemistry , University of Maryland Baltimore County (UMBC) , Baltimore , Maryland 21250 , United States.

The synthesis of a novel poly(propyleneimine) (PPI) dendron in gram scale as well as its use in the formation of a highly stable, dendronized gold nanoparticle (AuNP)-based drug delivery platform is described herein. The AuNP-based platform is composed of three complementary parts: (i) a 15 nm AuNP core, (ii) a heterofunctional thioctic acid-terminated tetraethylene glycol spacer, and (iii) a third-generation PPI dendron with a unique protonation profile and diverse end-group functionalization that allows for further derivatization. The prepared dendronized AuNPs are able to withstand several rounds of lyophilization cycles with no sign of aggregation, are stable in phosphate-buffered saline and Hanks' buffer as well as in serum, and are resistant to degradation by glutathione exchange reactions. This nanocarrier platform displays a dense coating, with >1400 dendrons/AuNPs, which will enable very high payload. Furthermore, while amine-terminated AuNPs expectedly showed cytotoxicity against the MCF-7 breast cancer cell line from a NP concentration of 1 nM, the mixed monolayer AuNPs (coated with 40/60 amine/carboxylate dendrons) interestingly did not exhibit any sign of toxicity at concentrations as high as 15 nM, similar to the carboxylate-terminated AuNPs. The described dendronized AuNPs address the current practical need for a stable NP-based drug delivery platform which is scalable and easily conjugable, has long-term stability in solution, and can be conveniently formulated as a powder and redispersed in desired buffer or serum.
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http://dx.doi.org/10.1021/acs.langmuir.8b03196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6499480PMC
March 2019

Dehydrative glycosylation with cyclic phosphonium anhydrides.

Org Biomol Chem 2016 Dec;15(1):51-55

Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.

Cyclic phosphonium anhydrides generated from bis-phosphine oxides and trifluoromethanesulfonic anhydride are shown as general coupling reagents in a dehydrative glycosylation reaction of C1-hemiacetals. This reaction protocol is characterized by a broad substrate scope and high yields, including reactions of O-, C-, N-, and S-based nucleophiles with furanose, pyranose, and deoxysugar donors.
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http://dx.doi.org/10.1039/c6ob01812bDOI Listing
December 2016

Packing density of rigid aggregates is independent of scale.

Proc Natl Acad Sci U S A 2014 Jun 9;111(25):9037-41. Epub 2014 Jun 9.

Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899; andDepartment of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742.

Large planetary seedlings, comets, microscale pharmaceuticals, and nanoscale soot particles are made from rigid, aggregated subunits that are compacted under low compression into larger structures spanning over 10 orders of magnitude in dimensional space. Here, we demonstrate that the packing density (θf) of compacted rigid aggregates is independent of spatial scale for systems under weak compaction. The θf of rigid aggregated structures across six orders of magnitude were measured using nanoscale spherical soot aerosol composed of aggregates with ∼ 17-nm monomeric subunits and aggregates made from uniform monomeric 6-mm spherical subunits at the macroscale. We find θf = 0.36 ± 0.02 at both dimensions. These values are remarkably similar to θf observed for comet nuclei and measured values of other rigid aggregated systems across a wide variety of spatial and formative conditions. We present a packing model that incorporates the aggregate morphology and show that θf is independent of both monomer and aggregate size. These observations suggest that the θf of rigid aggregates subject to weak compaction forces is independent of spatial dimension across varied formative conditions.
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http://dx.doi.org/10.1073/pnas.1403768111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4078842PMC
June 2014