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We propose an ultracompact parallel label-free biosensor based on concentric silicon-on-insulator microring resonators. Our numerical studies show that the proposed biosensor offers higher sensitivity and a larger detection area than conventional single-ring-based sensors. We analyze the detection sensitivity of the DNA hybridization by immobilizing the probe on top of the double concentric ring resonators and in the ring-ring air gap. For a concentric double-ring system with an area of 27.646 [micro][m.sup.2], the bulk detection sensitivity is 683 nm [RIU.sup.-1]. The sensitive uniformity of the system related to the optical field distribution is also studied. OCIS codes: 130.6010, 230.4555.

Multifunctional hydrogels with good stretchability and self‐healing properties have attracted considerable attention in the field of flexible electronic devices. However, hydrogels constructed by traditional chemical crosslinking usually have poor mechanical properties and lack self‐healing, adhesion, and biocompatibility, which cannot meet the requirements of flexible wearable devices. This work introduced multiple dynamic crosslinking, including borate ester bond, Schiff‐base, and host–guest interaction, into polymer networks to fabricate triple‐network gelatin/polyvinyl alcohol/carbon nanotube composite hydrogels with good self‐healing ability (healing efficiency of 95.0%), mechanical strength (54.6 kPa), stretchability (778%), biocompatibility, conductivity, adhesion, and remodeling properties. Carbon nanotubes can serve as the filler to improve the electrical conductivity of the triple‐network hydrogels. The resulting hydrogel can be made into a strain sensor with high strain sensitivity (gauge factor up to 16.0). More importantly, the strain sensor can be used to monitor various human and organ movements. Owing to its good self‐healing ability, the self‐healed hydrogel sensor also can detect human movements with almost the same electrical signal strength as the original one. This study gives novel insights for the design of multifunctional self‐healing hydrogels that have great potential in various application fields such as electronic skins, soft robots, and wearable devices. [ABSTRACT FROM AUTHOR]

Due to their unique physical and chemical features, dendronized polymers (DPs) have received increasing attention in various fields such as hierarchically structured materials, stimuli-responsive materials, catalysis, biosciences, optoelectronic devices, and so on. A large number of synthetic strategies also have been reported to prepare various functionalized DPs. Among these strategies, ring-opening metathesis polymerization (ROMP) and metathesis cyclopolymerization (MCP) using highly active and group-tolerant Ru-based catalysts as initiators were used as living and controlled techniques to fabricate well-defined DPs. The two efficient techniques present a promising prospect in the design and preparation of functional DPs. In this review, we focus on the synthesis of various classes of DPs by ROMP and MCP of dendritic macromonomers, and describe their characteristic structures and properties, as well as various functional applications. [ABSTRACT FROM AUTHOR]

Owing to their unique broken symmetry, amphiphilic Janus dendrimers and dendons provide fascinating properties for material, biological, pharmaceutical and biomedical applications. The integration of various organometallic moieties into these macromolecules will further offer the opportunity to form complex and intelligent architectures and materials. Here, we report a novel, simple and multifunctional Janus dendron containing redox‐reversible hydrophobic ferrocene (Fc) unit, complexing‐effective 1,2,3‐triazole ligand and biocompatible hydrophilic triethylene glycol termini. Silver and gold nanoparticles were firstly successfully prepared by using the Janus dendron as the reducing agent of Au(III) and Ag(I), and the stabilizer of the corresponding nanoparticles. The redox response of the Fc moiety was then employed to trigger the release of model drug, rhodamine B, encapsulated in supramolecular micelles formed by the self‐assembly of the Janus dendron. Finally, the precise and excellent metal‐complexing ability of the triazole group in this dendron was fully utilized to stabilize a water‐soluble Cu(I) catalyst, forming supramolecular nanoreactors for the catalysis of the copper(I)‐catalyzed azide alkyne cycloaddition click reaction in only water. The multifunctional characteristics of this dendron highlight the potential for organometallic Janus dendrimers and dendrons in the fields of functional materials and nanomedicines. [ABSTRACT FROM AUTHOR]