7 research outputs found
Hierarchical-Multiplex DNA Patterns Mediated by Polymer Brush Nanocone Arrays That Possess Potential Application for Specific DNA Sensing
This
paper provides a facile and cost-efficient method to prepare single-strand
DNA (ssDNA) nanocone arrays and hierarchical DNA patterns that were
mediated by polyÂ(2-hydroxyethyl methacrylate) (PHEMA) brush. The PHEMA
brush nanocone arrays with different morphology and period were fabricated
via colloidal lithography. The hierarchical structure was prepared
through the combination of colloidal lithography and traditional photolithography.
The DNA patterns were easily achieved via grafting the amino group
modified ssDNA onto the side chain of polymer brush, and the anchored
DNA maintained their reactivity. The as-prepared ssDNA nanocone arrays
can be applied for target DNA sensing with the detection limit reaching
1.65 nM. Besides, with the help of introducing microfluidic ideology,
the hierarchical-multiplex DNA patterns on the same substrate could
be easily achieved with each kind of pattern possessing one kind of
ssDNA, which are promising surfaces for the preparation of rapid,
visible, and multiplex DNA sensors
Autonomous Control of Fluids in a Wide Surface Tension Range in Microfluidics
In this paper, we report the preparation
of anisotropic wetting
surfaces that could control various wetting behaviors of liquids in
a wide surface tension range (from water to oil), which could be employed
as a platform for controlling the flow of liquids in microfluidics
(MFs). The anisotropic wetting surfaces are chemistry-asymmetric “Janus”
silicon cylinder arrays, which are fabricated via selecting and regulating
the functional groups on the surface of each cylinder unit. Liquids
(in a wide surface tension range) wet in a unidirectional manner along
the direction that was modified by the group with large surface energy.
Through introducing the Janus structure into a T-shaped pattern and
integrating it with an identical T-shaped polyÂ(dimethylsiloxane) microchannel,
the as-prepared chips can be utilized to perform as a surface tension
admeasuring apparatus or a one-way valve for liquids in a wide surface
tension range, even oil. Furthermore, because of the excellent ability
in controlling the flowing behavior of liquids in a wide surface tension
range in an open system or a microchannel, the anisotropic wetting
surfaces are potential candidates to be applied both in open MFs and
conventional MFs, which would broaden the application fields of MFs
Tunable Polymer Brush/Au NPs Hybrid Plasmonic Arrays Based on Host–guest Interaction
The fabrication of versatile gold
nanoparticle (Au NP) arrays with tunable optical properties by a novel
host–guest interaction are presented. The gold nanoparticles
were incorporated into polymer brushes by host–guest interaction
between β-cyclodextrin (β-CD) ligand of gold nanoparticles
and dimethylamino group of polyÂ(2-(dimethylamino)Âethyl methacrylate)
(PDMAEMA). The gold nanoparticle arrays were prepared through the
template of PDMAEMA brush patterns which were fabricated combining
colloidal lithography and surface-initiated atom-transfer radical
polymerization (SI-ATRP). The structure parameters of gold nanoparticle
patterns mediated by polymer brushes such as height, diameters, periods
and distances, could be easily tuned by tailoring the etching time
or size of colloidal spheres in the process of colloidal lithography.
The change of optical properties induced by different gold nanoparticle
structures was demonstrated. The direct utilization of PDMAEMA brushes
as guest avoids a series of complicated modification process and the
PDMAEMA brushes can be grafted on various substrates, which broaden
its applications. The prepared gold naoparticle arrays are promising
in applications of nanosensors, memory storage and surface enhanced
spectroscopy
Morphology-Patterned Anisotropic Wetting Surface for Fluid Control and Gas–Liquid Separation in Microfluidics
This
article shows morphology-patterned stripes as a new platform for directing
flow guidance of the fluid in microfluidic devices. Anisotropic (even
unidirectional) spreading behavior due to anisotropic wetting of the
underlying surface is observed after integrating morphology-patterned
stripes with a Y-shaped microchannel. The anisotropic wetting flow
of the fluid is influenced by the applied pressure, dimensions of
the patterns, including the period and depth of the structure, and
size of the channels. Fluids with different surface tensions show
different flowing anisotropy in our microdevice. Moreover, the morphology-patterned
surfaces could be used as a microvalve, and gas–water separation
in the microchannel was realized using the unidirectional flow of
water. Therefore, benefiting from their good performance and simple
fabrication process, morphology-patterned surfaces are good candidates
to be applied in controlling the fluid behavior in microfluidics
Modulate the Morphology and Spectroscopic Property of Gold Nanoparticle Arrays by Polymer-Assisted Thermal Treatment
In
this article, we report the morphology modulation of gold nanoparticle
(NP) arrays by polymer-assisted thermal treatment. Simultaneously,
localized surface plasmon resonance (LSPR) UV–vis extinction
(absorption plus scattering) of gold NP arrays was monitored and analyzed.
First, through horizontal lifting, gold NP monolayers were transferred
from a water/hexane interface to glass slides. After thin polymer
films were spin-coated on the gold NP monolayers, thermal treatment
was carried out, which results in apparent color changes in the obtained
samples. The color changes could be attributed to the shift of the
surface plasmon band (SPB), along with increasing gold NP size and
interparticle distance. We found that different polymers show different
effects on the modulation of gold NPs’ morphology, accompanied
by different shifts of the SPB. Polymers with relatively lower glass
transition temperatures (<i>T</i><sub>g</sub>), such as
polyÂ(methyl methacrylate), promoted gold NPs to merge into spheres,
while polymers with relatively higher <i>T</i><sub>g</sub>, such as polyphenylene sulfone resins, inhibited the fusion of gold
NPs, which collapsed as a whole slice. We believe that the difference
should be attributed to the polymer chain’s ability to move
during heating. Therefore, the temperature of thermal treatment and
the <i>T</i><sub>g</sub> of the polymer play critical roles
in the merging process of gold NPs. Moreover, through combining colloidal
lithography technology, patterned gold NP monolayers have been fabricated.
The current strategy is simple and facile to control the morphology
of gold NP arrays, as well as to control their optical properties
Elliptical Polymer Brush Ring Array Mediated Protein Patterning and Cell Adhesion on Patterned Protein Surfaces
This paper presents
a novel method to fabricate elliptical ring arrays of proteins. The
protein arrays are prepared by covalently grafting proteins to the
polymer brush ring arrays which are prepared by the techniques combining
colloidal lithography dewetting and surface initiated atom-transfer
radical polymerization (SI-ATRP). Through this method, the parameters
of protein patterns, such as height, wall thickness, periods, and
distances between two elliptical rings, can be finely regulated. In
addition, the sample which contains the elliptical protein ring arrays
can be prepared over a large area up to 1 cm<sup>2</sup>, and the
protein on the ring maintains its biological activity. The as-prepared
ring and elliptical ring arrays (ERAs) of fibronectin can promote
cell adhesion and may have an active effect on the formation of the
actin cytoskeleton
Unidirectional Wetting of Liquids on “Janus” Nanostructure Arrays under Various Media
We report the unidirectional
wetting behavior of liquids (water
and oil) on Janus silicon cylinder arrays (Si-CAs) under various media
(air, water, and oil). The Janus cylinders were prepared by chemical
modification of nanocylinders with different molecules on two sides.
Through adjusting surface energies of the modified molecules, the
as-prepared surfaces could control the wetting behavior of different
types of liquids under various media. We discuss the regularity systematically
and propose a strategy for preparing anisotropic wetting surfaces
under arbitrary media. That is, to find two surface modification molecules
with different surface energies, one of the molecules is easy to be
wetted by the liquid under the corresponding media, while the other
one is difficult. Additionally, by introducing thermal-responsive
polymer brushes onto one part of Janus Si-CAs, the surfaces show thermal-responsive
anisotropic wetting property under various media. We believe that
due to the excellent unidirectional wettability under various media,
the Janus surfaces could be applied in water/oil transportation, oil-repellent
and self-cleaning coatings, water/oil separation, microfluidics, and
so on