8 research outputs found
Fabrication of a Molecularly-Imprinted-Polymer-Based Graphene Oxide Nanocomposite for Electrochemical Sensing of New Psychoactive Substances
As new psychoactive substances (commonly known as âthe third generation drugsâ) have characteristics such as short-term emergence, rapid updating, and great social harmfulness, there is a large gap in the development of their detection methods. Herein, graphite oxide (GO) was first prepared and immobilized with a reversible addition-fragmentation chain transfer (RAFT) agent, then a new psychoactive substance (4-MEC) was chosen as a template, and then the surface RAFT polymerization of methacrylamide (MAAM) was carried out by using azobisisobutyronitrile (AIBN) as an initiator and divinylbenzene (DVB) as a cross-linker. After the removal of the embedded template, graphene oxide modified by molecularly imprinted polymers (GO-MIPs) was finally obtained. Owing to the specific imprinted cavities for 4-MEC, the satisfactory selectivity and stability of the GO-MIP nanocomposite have been demonstrated. The GO-MIP nanocomposite was then used to fabricate the electrochemical sensor, which displayed a high selectivity in detecting 4-MEC over a linear concentration range between 5 and 60 ÎŒg mLâ1 with a detection limit of 0.438 ÎŒg mLâ1. As a result, the GO-MIPs sensor developed an accurate, efficient, convenient, and sensitive method for public security departments to detect illicit drugs and new psychoactive substances
Adversarial Counterfactual Environment Model Learning
A good model for action-effect prediction, named environment model, is
important to achieve sample-efficient decision-making policy learning in many
domains like robot control, recommender systems, and patients' treatment
selection. We can take unlimited trials with such a model to identify the
appropriate actions so that the costs of queries in the real world can be
saved. It requires the model to handle unseen data correctly, also called
counterfactual data. However, standard data fitting techniques do not
automatically achieve such generalization ability and commonly result in
unreliable models. In this work, we introduce counterfactual-query risk
minimization (CQRM) in model learning for generalizing to a counterfactual
dataset queried by a specific target policy. Since the target policies can be
various and unknown in policy learning, we propose an adversarial CQRM
objective in which the model learns on counterfactual data queried by
adversarial policies, and finally derive a tractable solution GALILEO. We also
discover that adversarial CQRM is closely related to the adversarial model
learning, explaining the effectiveness of the latter. We apply GALILEO in
synthetic tasks and a real-world application. The results show that GALILEO
makes accurate predictions on counterfactual data and thus significantly
improves policies in real-world testing
Programmable Photoswitchable Microcapsules Enable Precise and Tailored Drug Delivery from Microfluidics
The
development of precision personalized medicine poses a significant
need for the next generation of advanced diagnostic and therapeutic
technologies, and one of the key challenges is the development of
highly time-, space-, and dose-controllable drug delivery systems
that respond to the complex physiopathology of patient populations.
In response to this challenge, an increasing number of stimuli-responsive
smart materials are integrated into biomaterial systems for precise
targeted drug delivery. Among them, responsive microcapsules prepared
by droplet microfluidics have received much attention. In this study,
we present a UV-visible light cycling mediated photoswitchable microcapsule
(PMC) with dynamic permeability-switching capability for precise and
tailored drug release. The PMCs were fabricated using a programmable
pulsed aerodynamic printing (PPAP) technique, encapsulating an aqueous
core containing magnetic nanoparticles and the drug doxorubicin (DOX)
within a poly(lactic-co-glycolic acid) (PLGA) composite shell modified
by PEG-b-PSPA. Selective irradiation of PMCs with ultraviolet (UV)
or visible light (Vis) allows for high-precision time-, space-, and
dose-controlled release of the therapeutic agent. An experimentally
validated theoretical model was developed to describe the drug release
pattern, holding promise for future customized programmable drug release
applications. The therapeutic efficacy and value of patternable cancer
cell treatment activated by UV radiation is demonstrated by our experimental
results. After in vitro transcatheter arterial chemoembolization (TACE),
PMCs can be removed by external magnetic fields to mitigate potential
side effects. Our findings demonstrate that PMCs have the potential
to integrate embolization, on-demand drug delivery, magnetic actuation,
and imaging properties, highlighting their immense potential for tailored
drug delivery and embolic therapy