Layer-by-Layer Assembled Smart Antibacterial Coatings via Mussel-Inspired Polymerization and Dynamic Covalent Chemistry

Bacterial colonization on the surface of medical implanted devices and bacterial infection-induced biofilm have been a lethal risk for patients of clinical treatment. While antibacterial coatings fabricated by layer-by-layer (LBL) assembly techniques have been well explored, the facile preparation of substrate-independent smart antibacterial coatings with on-demand antibiotics release profile and excellent antibacterial performance is still urgently needed. In this work, this goal is addressed by LBL assembly fabrication of robust antibacterial coatings using naturally occurring and commercially available building blocks (i.e., aminoglycosides, 5,6-dihydroxyindole, and formylphenylboronic acid) via the subsequentially performed mussel-inspired polymerization and dynamic covalent chemistries. The resulting antibacterial coatings on different substates all presente a dynamic feature (i.e., pH-responsive), on-demand antibiotics release properties, and highly effective antibacterial performance both in vitro and in vivo. It is envisioned that this work can expand the scope of LBL assembly technique toward the next generation of robust and universal antibacterial coating materials by using natural building blocks and readily available chemistries.

Cucurbit-Like Polymersomes with Aggregation-Induced Emission Properties Show Enzyme-Mediated Motility

Polymersomes that incorporate aggregation-induced emission (AIE) moieties are attractive inherently fluorescent nanoparticles with biomedical application potential for cell/tissue imaging and tracking, as well as phototherapeutics. An intriguing feature that has not been explored yet is their ability to adopt a range of asymmetric morphologies. Structural asymmetry allows nanoparticles to be exploited as active (motile) systems. Here, we present the design and preparation of AIE fluorophore integrated (AIEgenic) cucurbit-shaped polymersome nanomotors with enzyme-powered motility. The cucurbit scaffold was constructed via morphology engineering of biodegradable fluorescent AIE-polymersomes, followed by functionalization with enzymatic machinery via a layer-by-layer (LBL) self-assembly process. Because of the enzyme-mediated decomposition of chemical fuel on the cucurbit-like nanomotor surface, enhanced directed motion was attained, when compared with the spherical counterparts. These cucurbit-shaped biodegradable AIE-nanomotors provide a promising platform for the development of active delivery systems with potential for biomedical applications.

Plasmon-Enhanced Energy Transfer in Photosensitive Nanocrystal Device

Förster resonance energy transfer (FRET) interacted with localized surface plasmon (LSP) gives us the ability to overcome inadequate transfer of energy between donor and acceptor nanocrystals (NCs). In this paper, we show LSP-enhanced FRET in colloidal photosensors of NCs in operation, resulting in substantially enhanced photosensitivity. The proposed photosensitive device is a layered self-assembled colloidal platform consisting of separated monolayers of the donor and the acceptor colloidal NCs with an intermediate metal nanoparticle (MNP) layer made of gold interspaced by polyelectrolyte layers. Using LBL assembly, we fabricated and comparatively studied seven types of such NC-monolayer devices (containing only donor, only acceptor, Au MNP-donor, Au MNP-acceptor, donor-acceptor bilayer, donor-Au MNP-acceptor trilayer, and acceptor-Au MNP-donor reverse trilayer). In these structures, we revealed the effect of LSP-enhanced FRET and exciton interactions from the donor NCs layer to the acceptor NCs layer. Compared to a single acceptor NC device, we observed a significant extension in operating wavelength range and a substantial photosensitivity enhancement (2.91-fold) around the LSP resonance peak of Au MNPs in the LSP-enhanced FRET trilayer structure. Moreover, we present a theoretical model for the intercoupled donor-Au MNP-acceptor structure subject to the plasmon-mediated nonradiative energy transfer. The obtained numerical results are in excellent agreement with the systematic experimental studies done in our work. The potential to modify the energy transfer through mastering the exciton-plasmon interactions and its implication in devices make them attractive for applications in nanophotonic devices and sensors.

Layer-by-Layer Assembled 2D Montmorillonite Dielectrics for Solution-Processed Electronics

Layer-by-layer assembled 2D montmorillonite nanosheets are shown to be high-performance, solution-processed dielectrics. These scalable and spatially uniform sub-10 nm thick dielectrics yield high areal capacitances of ≈600 nF cm(-2) and low leakage currents down to 6 × 10(-9) A cm(-2) that enable low voltage operation of p-type semiconducting single-walled carbon nanotube and n-type indium gallium zinc oxide field-effect transistors.

Layer-by-Layer Assembly of Stable Aqueous Quantum Dots for Luminescent Planar Plate

This work reports the fabrication of a luminescent planar plate based on stable aqueous quantum dots (QDs) and poly(diallyldimethylammonium chloride) (PDDA) via a layer-by-layer (LBL) assembly technique. Preparation of aqueous QDs with facile monoalkyl maleate amphiphilic surfactants as the coating agent is conducted by a robust and efficient phase-transfer method. The as-prepared aqueous QDs exhibit bright emission, and their surface has very large negative zeta potential values, which are useful for electrostatic LBL assembly. Red, green, and blue luminescent planar plates are successfully fabricated via LBL assembly of the monocolor QDs, respectively. Through accurately adjusting the relative proportion of each monocolor luminescent component, we obtain an inspiring luminescent planar plate, which emits bright white light with a color coordinate of (0.3509, 0.3483), a correlated color temperature (CCT) of 4766 K, and a high color rendering index (CRI, Ra) of 89.5 under the irradiation of UV light. Therefore, this paper reports a facile process for the design and preparation of luminescent planar plates, which have potential applications in display and solid-state lighting devices.