24 research outputs found
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Injectable Interpenetrating Network Hydrogels via Kinetically Orthogonal Reactive Mixing of Functionalized Polymeric Precursors
The enhanced mechanics, unique chemistries,
and potential for domain
formation in interpenetrating network (IPN) hydrogels have attracted
significant interest in the context of biomedical applications. However,
conventional IPNs are not directly injectable in a biological context,
limiting their potential utility in such applications. Herein, we
report a fully injectable and thermoresponsive interpenetrating polymer
network formed by simultaneous reactive mixing of hydrazone cross-linked
poly(<i>N</i>-isopropylacrylamide) (PNIPAM), and thiosuccinimide
cross-linked poly(<i>N</i>-vinylpyrrolidone) (PVP). The
resulting IPN gels rapidly (<1 min) after injection without the
need for heat, UV irradiation, or small-molecule cross-linkers. The
IPNs, cross-linked by kinetically orthogonal mechanisms, showed a
significant synergistic enhancement in shear storage modulus compared
to the individual component networks as well as distinctive pore morphology,
degradation kinetics, and thermal swelling; in particular, significantly
lower hysteresis was observed over the thermal phase transition relative
to single-network PNIPAM hydrogels
A New Method for the Preparation of Concentrated Translucent Polymer Nanolatexes from Emulsion Polymerization
Mass Transport Limitations and Their Effect on the Control of the Molecular Weight Distribution in Catalytic Chain Transfer Mediated Emulsion Polymerization
pH-Ionizable <i>in Situ</i> Gelling Poly(oligo ethylene glycol methacrylate)-Based Hydrogels: The Role of Internal Network Structures in Controlling Macroscopic Properties
The incorporation
of charge within <i>in situ</i> covalently
gelling poly(oligo ethylene glycol methacrylate) (POEGMA) precursor
polymers enables the fabrication of hydrogels that exhibit both pH-responsive
swelling and tunable network structures due to multimechanism cross-linking
interactions. The gelation times, swelling responses, degradation
kinetics, and mechanics of the resulting gels were strongly influenced
by both the type of charge(s) incorporated and pH, with both amphoteric
gels and anionic gels showing clear evidence of dual network formation.
While the amphoteric dual network was anticipated due to charge interactions,
the mechanism of the 5-fold enhancement in mechanical properties observed
with the anionic gel relative to the neutral gel was revealed by isothermal
titration calorimetry and small-angle neutron scattering to relate
to the formation of a zippered chain structure based on dipole–dipole
interactions. Consequently, rational design of the chemistry and the
microscopic network structure results in controllable macroscopic
properties amenable to potential biomedical applications
Probing the Internal Morphology of Injectable Poly(oligoethylene glycol methacrylate) Hydrogels by Light and Small-Angle Neutron Scattering
While
injectable, <i>in situ</i> gelling hydrogels have
attracted increasing attention in the biomedical literature due to
their minimally invasive administration potential, little is known
about the internal morphology of these hydrogels and thus how to engineer
precursor polymer compositions to achieve desired hydrogel properties.
In this paper, the internal morphology of injectable <i>in situ</i> gelling hydrogels based on hydrazide and aldehyde-functionalized
poly(oligoethylene glycol methacrylate) precursors with varying lower
critical solution temperatures (LCSTs) is investigated using a combination
of spectrophotometry, small-angle neutron scattering, and light scattering.
If two precursor polymers with similar LCSTs are used to prepare the
hydrogel, relatively homogeneous hydrogels are produced (analogous
to conventional step-growth polymerized hydrogels); this result is
observed provided that gelation is sufficiently slow for diffusional
mixing to compensate for any incomplete mechanical mixing in the double-barrel
syringe and the volume phase transition temperature (VPTT) of the
hydrogel is sufficiently high that phase separation does not occur
on the time scale of gelation. Hydrogels prepared from precursor polymers
with different LCSTs (1 polymer/barrel) also retain transparency,
although their internal morphology is significantly less homogeneous.
However, if functionalized polymers with different LCSTs are mixed
in each barrel (i.e., 2 polymers/barrel, such that a gelling pair
of precursors with both low and high LCSTs is present), opaque hydrogels
are produced that contain significant inhomogeneities that are enhanced
as the temperature is increased; this suggests phase separation of
the hydrogel into lower and higher LCST domains. Based on this work,
the internal morphology of injectable hydrogels can be tuned by engineering
the gelation time and the physical properties (i.e., miscibility)
of the precursor polymers, insight that can be applied to improve
the design of such hydrogels for biomedical applications
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
Injectable On-Demand Pulsatile Drug Delivery Hydrogels Using Alternating Magnetic Field-Triggered Polymer Glass Transitions
Remote-controlled pulsatile or staged
release has significant potential in a wide range of therapeutic treatments.
However, most current approaches are hindered by the low resolution
between the on- and off-states of drug release and the need for surgical
implantation of larger controlled-release devices. Herein, we describe
a method that addresses these limitations by combining injectable
hydrogels, superparamagnetic iron oxide nanoparticles (SPIONs) that
heat when exposed to an alternating magnetic field (AMF), and polymeric
nanoparticles with a glass transition temperature (Tg) just above physiological temperature. Miniemulsion
polymerization was used to fabricate poly(methyl methacrylate-co-butyl methacrylate) (p(MMA-co-BMA))
nanoparticles loaded with a model hydrophobic drug and tuned to have
a Tg value just above physiological temperature
(∼43 °C). Co-encapsulation of these drug-loaded nanoparticles
with SPIONs inside a carbohydrate-based injectable hydrogel matrix
(formed by rapid hydrazone cross-linking chemistry) enables injection
and immobilization of the nanoparticles at the target site. Temperature
cycling facilitated a 2.5:1 to 6:1 on/off rhodamine release ratio
when the nanocomposites were switched between 37 and 45 °C; release
was similarly enhanced by exposing the nanocomposite hydrogel to an
AMF to drive heating, with enhanced release upon pulsing observed
even 1 week after injection. Coupled with the apparent cytocompatibility
of all of the nanocomposite components, these injectable nanocomposite
hydrogels are promising as minimally invasive but remotely actuated
release delivery vehicles capable of complex release kinetics with
high on–off resolution
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