Highly sensitive and selective two-photon sensing of cartap using Au@Ag core-shell nanoparticles

A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles.Cartap was found to induce the aggregation of Au@Ag nanoparticles and up to 700-fold enhancement in two-photon photoluminescence.Huge enhancement in two-photon photoluminescence allows achieving a detection limit of as low as 0.0062 mg/kg,which is better than the conventional colorimetric methods.This two-photon sensing scheme has a broad dynamic range and displays excellent selectivity in detection of cartap against over other ten kinds of commonly used insecticides.

Recent advances in hydrogel-based anti-infective coatings

Bacterial infections associated with biomedical devices and implants have posed a great challenge to global healthcare systems.These infections are mainly caused by bacterial biofilm formed on the surface of biomaterials,protecting the encapsulated bacteria from conventional antibiotic treatment and attack of the immune system.As the bacterial biofilm is difficult to eradicate,bactericidal and antifouling coatings have emerged as promising strategies to prevent biofilm fo rmation and subsequent infections.Hydrogels with three-dimensional crosslinked hydrophilic networks,tunable mechanical property and large drugloading capacity are desirable coating materials,which can kill bacteria and/or prevent bacterial adhesion on the surface,inhibiting biofilm formation.Herein,we review recent developments of hydrogels as anti-infective coatings.Particularly,we highlight two chemical approaches(graft-from and graft-to),which have been used to immobilize hydrogels on surfaces,and present advances in the development of bactericidal(contact-killing and antimicrobial-releasing),antifouling(hydrophilic polymer network)and bifunctional hydrogel coatings with both bactericidal and antifouling activities.In addition,the challe nges of hydrogel coatings for clinical applications are discussed,and future research directions of anti-infective hydrogel coatings are proposed.

Disjoint-Path Routing Mechanism in Mobile Opportunistic Networks

The prevalent multi-copy routing algorithms in mobile opportunistic networks(MONs)easily cause network congestion.This paper introduces a disjoint-path(DP)routing algorithm,where each node can only transmit packets once except the source node,to effectively control the number of packet copies in the network.The discrete continuous time Markov chain(CTMC)was utilized to analyze the state transition between nodes,and the copy numbers of packets with the DP routing algorithm were calculated.Simulation results indicate that DP has a great improvement in terms of packet delivery ratio,average delivery delay,average network overhead,energy and average hop count.