2 research outputs found
Asymmetric Colloidal Janus Particle Formation Is Core-Size-Dependent
Colloidal particles with asymmetric
surface chemistry (Janus particles)
have unique bifunctional properties. The size of these particles is
an important determinant for their applications in diverse fields
from drug delivery to chemical catalysis. The size of Janus particles,
with a core surface coated with carboxylate and a partially encapsulating
silica shell, depends upon several factors, including the core size
and the concentration of carboxylate coating. The role of the carboxylate
coating on the Janus particle size is well-understood; however, the
role of the core size is not well defined. The role of the carboxylated
polystyrene (cPS) core size on the cPS–silica Janus particle
morphology (its size and shape) was examined by testing two different
silica sizes and five different cPS core sizes. Results from electron
microscopy (EM) and dynamic light scattering (DLS) analysis indicate
that the composite cPS–silica particle acquires two distinct
shapes: (i) when the size of the cPS core is much smaller than the
non-cPS silica (b-SiO<sub>2</sub>) sphere, partially encapsulated
Janus particles are formed, and (ii) when the cPS core is larger than
or equal to the b-SiO<sub>2</sub> sphere, a raspberry-like structure
rather than a Janus particle is formed. The cPS–silica Janus
particles of ∼100–500 nm size were obtained when the
size of the cPS core was much smaller than the non-cPS silica (b-SiO<sub>2</sub>) sphere. These scalable nanoscale Janus particles will have
wide application in a multifunctional delivery platform and catalysis
Dual-Functionalized Theranostic Nanocarriers
Nanocarriers
with the ability to spatially organize chemically distinct multiple
bioactive moieties will have wide combinatory therapeutic and diagnostic
(theranostic) applications. We have designed dual-functionalized,
100 nm to 1 μm sized scalable nanocarriers comprising a silica
golf ball with amine or quaternary ammonium functional groups located
in its pits and hydroxyl groups located on its nonpit surface. These
functionalized golf balls selectively captured 10–40 nm charged
gold nanoparticles (GNPs) into their pits. The selective capture of
GNPs in the golf ball pits is visualized by scanning electron microscopy.
ζ
potential measurements and analytical modeling indicate that the GNP
capture involves its proximity to and the electric charge on the surface
of the golf balls. Potential applications of these dual-functionalized
carriers include distinct attachment of multiple agents for multifunctional
theranostic applications, selective scavenging, and clearance of harmful
substances