skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search for: All records

Creators/Authors contains: "Nielsen, Steven"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Qβ VLP simplified assembly approach uses the positively charged Rev tag to interact electrostatically with the negatively charged RNAs. This system exploits the known hairpins produced in the coat protein sequence to template the assembly of the full viral capsid. 
    more » « less
  2. null (Ed.)
  3. Many contrast agents for magnetic resonance imaging are based on gadolinium, however side effects limit their use in some patients. Organic radical contrast agents (ORCAs) are potential alternatives, but are reduced rapidly in physiological conditions and have low relaxivities as single molecule contrast agents. Herein, we use a supramolecular strategy where cucurbit[8]uril binds with nanomolar affinities to ORCAs and protects them against biological reductants to create a stable radical in vivo . We further overcame the weak contrast by conjugating this complex on the surface of a self-assembled biomacromolecule derived from the tobacco mosaic virus. 
    more » « less
  4. Abstract Plasmonic vesicle consists of multiple gold nanocrystals within a polymer coating or around a phospholipid core. As a multifunctional nanostructure, it has unique advantages of assembling small nanoparticles (<5 nm) for rapid renal clearance, strong plasmonic coupling for ultrasensitive biosensing and imaging, and near‐infrared light absorption for drug release. Thus, understanding the interaction of plasmonic vesicles with light is critically important for a wide range of applications. In this paper, a combined experimental and computational study is presented on the nanocrystal transformation in colloidal plasmonic vesicles induced by the ultrafast picosecond pulsed laser. Experimentally observed merging and transformation of small nanocrystals into larger nanoparticles when treated by laser pulses is first reported. The underlying mechanisms responsible for the experimental observations are investigated with a multiphysics computational approach featuring coupled electromagnetic/molecular dynamics simulation. This study reveals for the first time that combined nanoparticle heating and laser‐enhanced Brownian motion is responsible for the observed nanocrystal merging. Correspondingly, laser fluence, interparticle distance, and presence of water are identified as the most important factors governing the nanocrystal transformation. The guidelines established from this study can be employed to design a host of biomedical and nanomanufacturing applications involving laser interaction with plasmonic nanoparticles. 
    more » « less