Biomimetic channels based on carbon nanotubes (CNTs) with fast and selective transport have attractive applications in many fields. In this work, a remarkable and modulated enhancement in the ion transport rate through CNTs is facilitated by means of lipid decoration, by a factor of up to 20 times. A type of CNT membrane is firstly prepared, composed of well aligned multi-wall carbon nanotubes with an inner size of ∼10 nm. An inter-diffusion method is used to efficiently incorporate lipids within the CNTs. It is found that the lipid phase state as well as the surface property of the tubes' inner walls corporately determine the assembly behavior, such as location and stability of lipids, which further influence the ion transport rate through the tubes. For example, the incorporation and self-assembly of liquid-phase DOPC and polymerized Diyne-PC within the tubes induces an enhancement in steady ion transport rate through CNTs by a factor of 5 and 20 times, respectively. In contrast, the gel-phase DPPC prefers to stay at tube tips, which increases the ion transport rate during the initial stage only. This work provides a practical guide to regulate the ion transport behaviors through CNTs for versatile applications.

The quick response of magnetic nanoparticles (MNPs) to an external field provides a unique way for cellular manipulation in a remote and non-contact mode. In this work, we demonstrate the modulation of cellular behaviors including orientation and migration based on internalized Fe3O4 nanoparticles in a particle-concentration dependent manner. After being treated with MNPs at low concentrations (e.g. 0.277 μg mL−1), the internalized particles separately distributed around the nuclei, and somewhat influenced the orientation of the cells along the direction of the external magnetic field. In contrast, when the concentration of MNPs was high enough (e.g. 2.770 μg mL−1), the particles formed clusters within the cells and moved towards the edges of the cell in the direction of the magnetic field, leading to an obvious morphological change and subsequently a directed migration of the cells. This result shows a facile way to manipulate cell behaviors with excellent biocompatibility and its potential application in the biomedical field such as in tissue engineering.

Cellular uptake of materials plays a key role in their biomedical applications. In this work, based on the cell-mimic giant unilamellar vesicles (GUVs) and a novel type of microscale materials consisting of stimuli-responsive poly(N-isopropylacrylamide) microgel particles and the incorporated lipids, the influence of particle surface chemistry, including hydrophobic/hydrophilic property and lipid decorations, on the adsorption and consequent internalization of particles into GUVs was investigated. It is found that the decoration of particle surface with lipids facilitates the adsorption of particles on GUV membrane. After that, the hydrophobic property of particle surface further triggers the internalization of particles into GUVs. These results demonstrate the importance of surface properties of particles on their interactions with lipid membranes and are helpful to the understanding of cellular uptake mechanism.

•A type of plasmonic Ag@Si chips composing of Si supported Ag film was fabricated.•The chips show viable integration into fluorescent immunoassays for enhancement.•The chips show up to 57 times enhancement at 800 nm in fluorescence protein assay.•The chips show up to 4.1 times fluorescence enhancement for cell and tissue imaging.Metal-enhanced fluorescence shows great potential for improving the sensitivity of fluoroscopy, which has been widely used in protein and nucleic acid detection for biosensor and bioassay applications. In comparison with the traditional glass-supported metal nanoparticles (MNPs), the introduction of a silicon substrate has been shown to provide an increased surface-enhanced Raman scattering (SERS) effect due to the coupling between the MNPs and the semiconducting silicon substrate. In this work, we further study the fluorescence-enhanced effect of the silicon-supported silver-island (Ag@Si) plasmonic chips. In particular, we investigate their practical application of improving the traditional immunoassay such as the biotin-streptavidin-based protein assay and the protein-/nucleic acid-labeled cell and tissue samples. The protein assay shows a wavelength-dependent enhancement effect of the Ag@Si chip, with an enhancement factor ranging from 1.2 (at 532 nm) to 57.3 (at 800 nm). Moreover, for the protein- and nucleic acid-labeled cell and tissue samples, the Ag@Si chip provides a fluorescence enhancement factor of 3.0–4.1 (at 800 nm) and a significant improvement in the signal/background ratio for the microscopy images. Such a ready accommodation of the fluorescence-enhanced effect for the immunoassay samples with simple manipulations indicates broad potential for applications of the Ag@Si chip not only in biological studies but also in the clinical field.

The quick response of magnetic nanoparticles (MNPs) to an external field provides a unique way for cellular manipulation in a remote and non-contact mode. In this work, we demonstrate the modulation of cellular behaviors including orientation and migration based on internalized Fe3O4 nanoparticles in a particle-concentration dependent manner. After being treated with MNPs at low concentrations (e.g. 0.277 μg mL−1), the internalized particles separately distributed around the nuclei, and somewhat influenced the orientation of the cells along the direction of the external magnetic field. In contrast, when the concentration of MNPs was high enough (e.g. 2.770 μg mL−1), the particles formed clusters within the cells and moved towards the edges of the cell in the direction of the magnetic field, leading to an obvious morphological change and subsequently a directed migration of the cells. This result shows a facile way to manipulate cell behaviors with excellent biocompatibility and its potential application in the biomedical field such as in tissue engineering.