Electrospinning of Poly(L-lactide) Nanofibers Encapsulated with Water-Soluble Fullerenes for Bioimaging Application

Photoluminescent fullerene nanoparticles/nanofibers have potential applications in bioimaging. A novel fluorescent nanofibrous material, consisting of fullerene nanoparticles and poly­(L-lactide) (PLLA), was fabricated via a simple electrospinning method, and the composite nanofibers were characterized by various techniques such as scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), and transmission electron microscopy (TEM). The nanofibers were uniform, and their surfaces were reasonably smooth, with the average diameters of fibers ranging from 300 to 600 nm. The fullerene nanoparticles were encapsulated within the composite nanofibers, forming a core–shell structure. The nanofiber scaffolds showed excellent hydrophilic surface due to the addition of water-soluble fullerene nanoparticles. The composite nanofibers used as substrates for bioimaging <i>in vitro</i> were evaluated with human liver carcinoma HepG2 cells, the fullerene nanoparticles signal almost displayed in every cell, implying the potential of fluorescent fullerene nanoparticles/PLLA nanofibers to be used as scaffolds for bioimaging application

Making and Remaking Dynamic 3D Structures by Shining Light on Flat Liquid Crystalline Vitrimer Films without a Mold

Making dynamic three-dimensional (3D) structures capable of reversible shape changes or locomotion purely out of dry polymers is very difficult. Meanwhile, no previous dynamic 3D structures can be remade into new configurations while being resilient to mechanical damages and low temperature. Here, we show that light-activated transesterification in carbon nanotube dispersed liquid crystalline vitrimers enables flexible design and easy building of dynamic 3D structures out of flat films upon irradiation of light without screws, glues, or molds. Shining light also enables dynamic 3D structures to be quickly modified on demand, restored from distortion, repaired if broken, in situ healed when microcrack appears, assembled for more sophisticated structures, reconfigured, and recycled after use. Furthermore, the fabrication, reconfiguration, actuation, reparation, and assembly as well as healing can be performed even at extremely low temperatures (e.g., −130 °C)

Nonspherical Liquid Crystalline Assemblies with Programmable Shape Transformation

Liquid crystalline (LC) assemblies with tailored shape and programmable shape transformation were prepared via polymerization-induced self-assembly. The influence of polymerization temperature and solvent on the shape of the LC assemblies indicated that shape of the LC assemblies could be delicately regulated by the repulsive interaction among the solvophilic chains and LC ordering. Programmable shape transformation of ellipsoidal LC assemblies was achieved, taking advantage of the smectic-to-isotropic phase transition. The ellipsoidal assemblies could remain ellipsoids or transform to faceted spheres and spheres, depending on the temperature procedure used. Besides, the generated spheres could be reshaped to ellipsoids with high shape recovery ratio. Small angle X-ray scattering study indicated that the interplay of the reversible smectic-to-isotropic phase transition and kinetic trapping underpins the programmed shape transformation. As a general approach to LC assemblies with programmable shape transformation, our strategy would provide a reliable platform for nanoactuators, nanomotors, and adaptive colloidal devices

A New Class of Red Fluorescent Organic Nanoparticles: Noncovalent Fabrication and Cell Imaging Applications

Cyano-substituted diarylethlene derivatives <b>R-OMe (-H, -CF</b>_<b>3</b><b>)</b> with different peripheral substituted groups were synthesized in high yield. Water-soluble red fluorescent organic nanoparticles (FONs) could be facilely prepared from them via hydrophobic interaction with polyoxyethylene–­polyoxypropylene–­polyoxyethylene triblock copolymer (Pluronic F127). The optical properties and surface morphology of the synthesized FONs were characterized, and their biocompatibilities as well as their applications in cell imaging were further investigated. We demonstrate that such red FONs exhibit antiaggregation-caused quenching properties, broad excitation wavelengths, excellent water dispersibilities, and biocompatibilities, making them promising for cell imaging

Dual-Responsive Controlled Drug Delivery Based on Ionically Assembled Nanoparticles

Ionically assembled nanoparticles (INPs) have been formed from poly­(ionic liquid-<i>co</i>-<i>N</i>-isopropylacrylamide) with deoxycholic acid through electrostatic interaction. The structure and properties of the INPs were investigated by using ¹H NMR, Fourier transform infrared (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and so on. Due to pH-responsive deoxycholic acid (p<i>K</i>_a = 6.2) and thermo responsive <i>N</i>-isopropylacrylamide included in the ionic complex, the INPs exhibit highly pH and thermal dual-responsive properties. The potential practical applications as drug delivery carriers were demonstrated using doxorubicin (DOX) as a model drug. With a lower pH (pH 5.2) and higher temperature (above 37 °C), structural collapse of the INPs occurred as well as release of DOX owing to protonated DA departure from the INPs and a lower LCST (lower critical solution temperature) at the pathological conditions. The result shows that 80% of DOX molecules were released from INPs within 48 h at pH 5.2, 43 °C, but only 30% of the drug was released within 48 h at 37 °C and pH 7.4. Moreover, drug-loaded INPs exhibit an inhibitory effect on cell growth

One-Step Coating toward Multifunctional Applications: Oil/Water Mixtures and Emulsions Separation and Contaminants Adsorption

Here, a method that can simultaneously separate oil/water mixtures and remove water-soluble contaminants has been developed. Various substrates with different pore size were coated by polydopamine and polyethylenepolyamine codeposition films. The as-prepared materials were superhydrophilic and under-water superoleophobic. The materials can separate a range of different oil/water mixtures (including immiscible oil/water mixtures and surfactant-stabilized emulsions) in a single unit operation, with >99.6% separation efficiency and high fluxes. Copper ion and methyl blue can be effectively absorbed from water when it permeates through the materials. This method can be applied on organic and inorganic substrates and used in preparing large-scale product. Therefore, the simple and facile method has excellent potential in practical application and creates a new field for oil/water separation materials with multifunctional applications

PLA-PEG-PLA and Its Electroactive Tetraaniline Copolymer as Multi-interactive Injectable Hydrogels for Tissue Engineering

Injectable hydrogels have served as biomimic scaffolds that provide a three-dimensional (3D) structure for tissue engineering or carriers for cell encapsulation in the biomedical field. In this study, the injectable electroactive hydrogels (IEHs) were prepared by introducing electrical properties into the injectable materials. Carboxyl-capped tetraaniline (CTA) as functional group was coupled with enantiomeric polylactide–poly­(ethylene glycol)–polylactide (PLA-PEG-PLA), and the electroactive hydrogels were obtained by mixing the enantiomeric copolymers of CTA-PLLA-PEG-PLLA-CTA and CTA-PDLA-PEG-PDLA-CTA aqueous solutions. ultraviolet–visible spectroscopy (UV–vis) and cyclic voltammetry (CV) of the complex solution showed good electroactive properties. The gelation mechanism and intermolecular multi-interactions such as stereocomplextion, hydrogen bonding, and π–π stacking were studied by Fourier transform infrared spectroscopy (FT-IR), UV–vis, and wide-angle X-ray diffraction (WAXD). Gelation properties of the complexes were also studied by rheometer. The encapsulated cells remained highly viable in the gel matrices, suggesting that the hydrogels have excellent cytocompatibility. After subcutaneous injection, the gels were formed in situ in the subcutaneous layer, and hematoxylin–eosin (H&E) staining suggested acceptable biocompatibility of our materials in vivo. Moreover, these injectable materials, when treated with pulsed electrical stimuli, were shown to be functionally active and to accelerate the proliferation of encapsulated fibroblasts, cardiomyocytes, and osteoblasts. Hence, the IEHs possessing these excellent properties would be potentially used as in vivo materials for tissue engineering scaffold

A Facile Solvent-Manipulated Mesh for Reversible Oil/Water Separation

A controllable oil/water separation mesh has been successfully developed and easily manipulated by immersion in a stearic acid ethanol solution and tetrahydrofuran with a very short period of time. The superhydrophilic and underwater superoleophobic mesh is first obtained via a one-step chemical oxidation and subsequently converts to superhydrophobic after it is immersed in an ethanol solution of stearic acid for 5 min. The surface wettability is regained to superhydrophilic quickly by immersion in tetrahydrofuran for 5 min. More importantly, the reversible superhydrophobic-and-superhydrophilic switching can be repeated multiple times with almost no visible morphology variation. Therefore, this approach provides potential application in controllable oil/water separation and opens up new perspectives in manipulation of various metallic oxide substrates

A Facile Solvent-Manipulated Mesh for Reversible Oil/Water Separation

A controllable oil/water separation mesh has been successfully developed and easily manipulated by immersion in a stearic acid ethanol solution and tetrahydrofuran with a very short period of time. The superhydrophilic and underwater superoleophobic mesh is first obtained via a one-step chemical oxidation and subsequently converts to superhydrophobic after it is immersed in an ethanol solution of stearic acid for 5 min. The surface wettability is regained to superhydrophilic quickly by immersion in tetrahydrofuran for 5 min. More importantly, the reversible superhydrophobic-and-superhydrophilic switching can be repeated multiple times with almost no visible morphology variation. Therefore, this approach provides potential application in controllable oil/water separation and opens up new perspectives in manipulation of various metallic oxide substrates

Facile Preparation of Biocompatible and Robust Fluorescent Polymeric Nanoparticles via PEGylation and Cross-Linking

Novel cross-linked copolymers of <b>PEG-IM-PhNH</b>_<b>2</b> are successfully synthesized through PEGylation via radical polymerization of 2-isocyanatoethyl methacrylate and poly­(ethylene glycol) monomethyl ether methacylate and subsequent cross-linking with an amino-terminated aggregation-induced emission fluorogen. Such obtained amphiphilic copolymers can self-assemble to form uniform fluorescent polymeric nanoparticles (FPNs) and be utilized for cell imaging. These cross-linked FPNs are demonstrated good water dispersibility with ultralow critical micelle concentration (∼0.002 mg mL^–1), uniform morphology (98 ± 2 nm), high red fluorescence quantum yield, and excellent biocompatibility. More importantly, this novel strategy of fabricating cross-linked FPNs paves the way to the future development of more robust and biocompatible fluorescent bioprobes