Hybrid Zn-β-Aminoporphyrin-Carbon Nanotubes: Pyrrolidine and Direct Covalent Linkage Recognition, and Multiple-Photo Response

To unveil and shape the molecular connectivity in (metallo)porphyrin-carbon nanotube hybrids are of main relevance for the multiple medicinal, photoelectronic, catalytic, and photocatalytic applications of these materials. Multi-walled carbon nanotubes (MWCNTs) were modified through 1,3-dipolar cycloaddition reactions with azomethine ylides generated in situ and carrying pentafluorophenyl groups, followed by immobilization of the β-amino-tetraphenylporphyrinate Zn(II). The functionalities were confirmed via XPS and FTIR, whereas Raman spectroscopy showed disruptions on the graphitic carbon nanotube surface upon both steps. The functionalization extension, measured via TGA mass loss and corroborated via XPS, was 0.2 mmol·g-1. Photophysical studies attest to the presence of the different porphyrin-carbon nanotube connectivity in the nanohybrid. Significantly different emission spectra and fluorescence anisotropy of 0.15-0.3 were observed upon variation of excitation wavelength. Vis-NIR absorption and flash photolysis experiments showed energy/charge transfer in the photoactivated nanohybrid. Moreover, evidence was found for direct reaction of amino groups with a carbon nanotube surface in the presence of molecular dipoles such as the zwitterionic sarcosine amino acid.

Synthesis of Multifunctional Mn3O4-Ag2S Janus Nanoparticles for Enhanced T1-Magnetic Resonance Imaging and Photo-Induced Tumor Therapy

The global burden of cancer is increasing rapidly, and nanomedicine offers promising prospects for enhancing the life expectancy of cancer patients. Janus nanoparticles (JNPs) have garnered considerable attention due to their asymmetric geometry, enabling multifunctionality in drug delivery and theranostics. However, achieving precise control over the self-assembly of JNPs in solution at the nanoscale level poses significant challenges. Herein, a low-temperature reversed-phase microemulsion system was used to obtain homogenous Mn3O4-Ag2S JNPs, which showed significant potential in cancer theranostics. Structural characterization revealed that the Ag2S (5-10 nm) part was uniformly deposited on a specific surface of Mn3O4 to form a Mn3O4-Ag2S Janus morphology. Compared to the single-component Mn3O4 and Ag2S particles, the fabricated Mn3O4-Ag2S JNPs exhibited satisfactory biocompatibility and therapeutic performance. Novel diagnostic and therapeutic nanoplatforms can be guided using the magnetic component in JNPs, which is revealed as an excellent T1 contrast enhancement agent in magnetic resonance imaging (MRI) with multiple functions, such as photo-induced regulation of the tumor microenvironment via producing reactive oxygen species and second near-infrared region (NIR-II) photothermal excitation for in vitro tumor-killing effects. The prime antibacterial and promising theranostics results demonstrate the extensive potential of the designed photo-responsive Mn3O4-Ag2S JNPs for biomedical applications.

Guest-Driven Light-Induced Spin Change in an Azobenzene Loaded Metal-Organic Framework

Stimuli-responsive materials that can be reversibly switched by light are of immense interest. Among them, photo-responsive spin crossover (SCO) complexes have great promises to combine the photoactive inputs with multifaceted outputs into switchable materials and devices. However, the reversible control the spin-state change by photochromic guests is still challenging. Herein, we report an unprecedented guest-driven light-induced spin change (GD-LISC) in a Hofmann-type metal-organic framework (MOF), [Fe(bpn){Ag(CN)₂ }₂ ]⋅azobenzene. (1, bpn=1,4-bis(4-pyridyl)naphthalene). The reversible trans-cis photoisomerization of azobenzene guest upon UV/Vis irradiation in the solid-state results in the remarkable magnetic changes in a wide temperature range of 10-180 K. This finding not only establishes a new switching mechanism for SCO complexes, but also paves the way toward the development of new generation of photo-responsive magnetic materials.

Hierarchical Self-Assembled Photo-Responsive Tubisomes from a Cyclic Peptide-Bridged Amphiphilic Block Copolymer

Typically, the morphologies of the self-assembled nanostructures from block copolymers are limited to spherical micelles, wormlike micelles and vesicles. Now, a new generation of materials with unique shape and structures, cylindrical soft matter particles (tubisomes), are obtained from the hierarchical self-assembly of cyclic peptide-bridged amphiphilic diblock copolymers. The capacity of obtained photo-responsive tubisomes as potential drug carriers is evaluated. The supramolecular tubisomes pave an alternative way for fabricating polymeric tubular structures, and will expand the toolbox for the rational design of functional hierarchical nanostructures.

Liquid Crystal Networks on Thermoplastics: Reprogrammable Photo-Responsive Actuators

Arbitrary shape (re)programming is appealing for fabricating untethered shape-morphing photo-actuators with intricate configurations and features. We present re-programmable light-responsive thermoplastic actuators with arbitrary initial shapes through spray-coating of polyethylene terephthalate (PET) with an azobenzene-doped light-responsive liquid crystal network (LCN). The initial geometry of the actuator is controlled by thermally shaping and fixing the thermoplastic PET, allowing arbitrary shapes, including origami-like folds and left- and right-handed helicity within a single sample. The thermally fixed geometries can be reversibly actuated through light exposure, with fast, reversible area-specific actuation such as winding, unwinding and unfolding. By shape re-programming, the same sample can be re-designed and light-actuated again. The strategy presented here demonstrates easy fabrication of mechanically robust, recyclable, photo-responsive actuators with highly tuneable geometries and actuation modes.