5 research outputs found
Poly(oligoethylene glycol methacrylate) Dip-Coating: Turning Cellulose Paper into a Protein-Repellent Platform for Biosensors
The
passivation of nonspecific protein adsorption to paper is a
major barrier to the use of paper as a platform for microfluidic bioassays.
Herein we describe a simple, scalable protocol based on adsorption
and cross-linking of poly(oligoethylene glycol methacrylate) (POEGMA)
derivatives that reduces nonspecific adsorption of a range of proteins
to filter paper by at least 1 order of magnitude without significantly
changing the fiber morphology or paper macroporosity. A lateral-flow
test strip coated with POEGMA facilitates effective protein transport
while also confining the colorimetric reporting signal for easier
detection, giving improved performance relative to bovine serum albumin
(BSA)-blocked paper. Enzyme-linked immunosorbent assays based on POEGMA-coated
paper also achieve lower blank values, higher sensitivities, and lower
detection limits relative to ones based on paper blocked with BSA
or skim milk. We anticipate that POEGMA-coated paper can function
as a platform for the design of portable, disposable, and low-cost
paper-based biosensors
A Highly Sensitive Immunosorbent Assay Based on Biotinylated Graphene Oxide and the Quartz Crystal Microbalance
A high-sensitivity
flow-based immunoassay is reported based on a gold-coated quartz crystal
microbalance (QCM) chip functionalized directly in the QCM without
requiring covalent conjugation steps. Specifically, the irreversible
adsorption of a biotinylated graphene oxide-avidin complex followed
by loading of a biotinylated capture antibody is applied to avoid
more complex conventional surface modification chemistries and enable
chip functionalization and sensing all within the QCM instrument.
The resulting immunosensors exhibit significantly lower nonspecific
protein adsorption and stronger signal for antigen sensing relative
to simple avidin-coated sensors. Reproducible quantification of rabbit
IgG concentrations ranging from 0.1 ng/mL to 10 μg/mL (6 orders
of magnitude) can be achieved depending on the approach used to quantify
the binding with simple mass changes used to detect higher concentrations
and a horseradish peroxidase-linked detection antibody that converts
its substrate to a measurable precipitate used to detect very low
analyte concentrations. Sensor fabrication and assay performance take
∼5 h in total, which is on par with or faster than other techniques.
Quantitative sensing is possible in the presence of complex protein
mixtures, such as human plasma. Given the broad availability of biotinylated
capture antibodies, this method offers both an easy and flexible platform
for the quantitative sensing of a variety of biomolecule targets
“Click” Chemistry-Tethered Hyaluronic Acid-Based Contact Lens Coatings Improve Lens Wettability and Lower Protein Adsorption
Improving the wettability
of and reducing the protein adsorption to contact lenses may be beneficial
for improving wearer comfort. Herein, we describe a simple “click”
chemistry approach to surface functionalize poly(2-hydroxyethyl methacrylate)
(pHEMA)-based contact lenses with hyaluronic acid (HA), a carbohydrate
naturally contributing to the wettability of the native tear film.
A two-step preparation technique consisting of laccase/TEMPO-mediated
oxidation followed by covalent grafting of hydrazide-functionalized
HA via simple immersion resulted in a model lens surface that is significantly
more wettable, more water retentive, and less protein binding than
unmodified pHEMA while maintaining the favorable transparency, refractive,
and mechanical properties of a native lens. The dipping/coating method
we developed to covalently tether the HA wetting agent is simple,
readily scalable, and a highly efficient route for contact lens modification
Supplemental material for Silk fibroin/chitosan thin film promotes osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells
<p>Supplemental material for Silk fibroin/chitosan thin film promotes osteogenic and adipogenic differentiation of rat bone marrow-derived mesenchymal stem cells by Da-Wei Li, Jin He, Feng-Li He, Ya-Li Liu, Yang-Yang Liu, Ya-Jing Ye, Xudong Deng and Da-Chuan Yin in Journal of Biomaterials Applications</p
Autonomously Self-Adhesive Hydrogels as Building Blocks for Additive Manufacturing
We
report a simple method of preparing autonomous and rapid self-adhesive
hydrogels and their use as building blocks for additive manufacturing
of functional tissue scaffolds. Dynamic cross-linking between 2-aminophenylboronic
acid-functionalized hyaluronic acid and poly(vinyl alcohol) yields
hydrogels that recover their mechanical integrity within 1 min after
cutting or shear under both neutral and acidic pH conditions. Incorporation
of this hydrogel in an interpenetrating calcium-alginate network results
in an interfacially stiffer but still rapidly self-adhesive hydrogel
that can be assembled into hollow perfusion channels by simple contact
additive manufacturing within minutes. Such channels withstand fluid
perfusion while retaining their dimensions and support endothelial
cell growth and proliferation, providing a simple and modular route
to produce customized cell scaffolds