Glossary - Viral Nanoparticles: Tools for Materials Science and Biomedicine - page 254

Density gradient
ultracentrifugation

A separation or purification method, in which
molecules are separated based on their density
(density = mass per volume).

Diazonium coupling Diazonium coupling or azo coupling is the reaction

between a diazonium salt and a phenol; the phenol
could be derived from a tyrosine side chain.

Dip-pen
nanolithography

An AFM tip is used as a “pen,” which is coated with
chemical linkers, the “ink.” The tip (or “pen”) is
brought into contact with the substrate, which can
be regarded as the “paper.” The molecules (that is the
“ink”) are transferred onto the surface (the “paper”)
using solvent meniscus effects. Structures on the
nanoscale can be written using this technique.

DNA microarray DNA microarray technology allows analysis or

screening of several thousand DNA molecules on a
chip. DNA molecules are first bound on a chip; the
immobilized DNA is referred to as target DNA. The
DNA chip or DNA array is then probed with RNA or
cDNA samples, the probes. If the sequences match,
the probe binds the target via base pairing. Detection
of hybridization events is typically carried out using
fluorescent-labeled probes.

Dynamic light
scattering

A spectroscopy technique that utilizes scattered
light to determine the size and radius of small
particles or proteins.

Electron microscopy Electron microscopes fire high-energy electrons

instead of photons (optical microscopes) toward
the sample and create an electronically magnified
image that can reach a magnification of 1,000,000 ×
and allows visualization of objects in the nanometer-
size scale.

Electrospinning Electrospinning uses high voltage to draw fibers

from a liquid.

Electrostatic
interactions

These are ionic interactions between oppositely
charged molecules. Positively and negatively
charged molecules are attracted to each other
(opposites attract).