Recent advances in the area of quantum dots (QDs) have shown their wide range of applications that extend from sensing [50] and bioimaging to catalytic water splitting owing to their remarkable electronic,e lectrochemical, optical, and catalytic properties. [51, 52] Thes ynthesis of QDs can be Alain R. Puente Santiago received his PhD degree in Physical Chemistry with distinction from the University of Cordova, Spain in 2017. He is currently apostdoctoral fellow in Prof. Luis Echegoyen's group in the Chemistry Department of the University of Texas at El Paso. His research interests focus on the developmento flow-dimensional nanohybrids for electrocatalysis. Olivia Fernandez-Delgado was born in Cuba (Havana) in 1993. She obtained her B.S. in Chemistry from the University of Havana in 2016. She is currently pursuing her Ph.D. in the group of Prof. Luis Echegoyen in the University of Texas at El Paso. Her research interests include the synthesis and characterization of new fullerene and carbon nanoonion derivativesf or photovoltaic, catalytic, and biological applications.

Polymersomes are being widely explored as synthetic analogs of lipid vesicles based on their enhanced stability and potential uses in a wide variety of applications in (e.g., drug delivery, cell analogs, etc.). Controlled formation of giant polymersomes for use in membrane studies and cell mimetic systems, however, is currently limited by low-yield production methodologies. Here, we describe for the first time, how the size distribution of giant poly(ethylene glycol)-poly(butadiene) (PEO-PBD) polymersomes formed by gel-assisted rehydration may be controlled based on membrane fluidization. We first show that the average diameter and size distribution of PEO-PBD polymersomes may be readily increased by increasing the temperature of the rehydration solution. Further, we describe a correlative relationship between polymersome size and membrane fluidization through the addition of sucrose during rehydration, enabling the formation of PEO-PBD polymersomes with a range of diameters, including giant-sized vesicles (>100 μm). This correlative relationship suggests that sucrose may function as a small molecule fluidizer during rehydration, enhancing polymer diffusivity during formation and increasing polymersome size. Overall the ability to easily regulate the size of PEO-PBD polymersomes based on membrane fluidity, either through temperature or fluidizers, has broadly applicability in areas including targeted therapeutic delivery and synthetic biology.

This article describes the three-dimensional self-assembly of monodisperse colloidal magnetite nanoparticles (NPs) from a dilute water-based ferrofluid onto a silicon surface and the dependence of the resultant magnetic structure on the applied field. The NPs assemble into close-packed layers on the surface followed by more loosely packed ones. The magnetic field-dependent magnetization of the individual NP layers depends on both the rotational freedom of the layer and the magnetization of the adjacent layers. For layers in which the NPs are more free to rotate, the easy axis of the NP can readily orient along the field direction. In more dense packing, free rotation of the NPs is hampered, and the NP ensembles likely build up quasi-domain states to minimize energy, which leads to lower magnetization in those layers. Detailed analysis of polarized neutron reflectometry data together with model calculations of the arrangement of the NPs within the layers and input from small-angle scattering measurements provide full characterization of the core/shell NP dimensions, degree of chaining, arrangement of the NPs within the different layers, and magnetization depth profile.

Hydrogels have been extensively used for regenerative medicine strategies given their tailorable mechanical and chemical properties. Gene delivery represents a promising strategy by which to enhance the bioactivity of the hydrogels, though the efficiency and localization of gene transfer have been challenging. Here, we functionalized porous poly(ethylene glycol) hydrogels with heparin-chitosan nanoparticles to retain the vectors locally and enhance lentivirus delivery while minimizing changes to hydrogel architecture and mechanical properties. The immobilization of nanoparticles, as compared to homogeneous heparin and/or chitosan, is essential to lentivirus immobilization and retention of activity. Using this gene-delivering platform, we over-expressed the angiogenic factors sonic hedgehog (Shh) and vascular endothelial growth factor (Vegf) to promote blood vessel recruitment to the implant site. Shh enhanced endothelial recruitment and blood vessel formation around the hydrogel compared to both Vegf-delivering and control hydrogels. The nanoparticle-modified porous hydrogels for delivering gene therapy vectors can provide a platform for numerous regenerative medicine applications.

Self-assembled giant polymer vesicles prepared from double-hydrophilic diblock copolymers, poly(ethylene oxide)-b-poly(acrylic acid) (PEO-PAA) show significant degradation in response to pH changes. Because of the switching behavior of the diblock copolymers at biologically-relevant pH environments (2 to 9), these polymer vesicles have potential biomedical applications as smart delivery vehicles.

We describe for the first time how biological nanomotors may be used to actively self-assemble mesoscale networks composed of diblock copolymer nanotubes. The collective force generated by multiple kinesin nanomotors acting on a microtubule filament is large enough to overcome the energy barrier required to extract nanotubes from polymer vesicles comprised of poly(ethylene oxide-b-butadiene) in spite of the higher force requirements relative to extracting nanotubes from lipid vesicles. Nevertheless, large-scale polymer networks were dynamically assembled by the motors. These networks displayed enhanced robustness, persisting more than 24 h post-assembly (compared to 4-5 h for corresponding lipid networks). The transport of materials in and on the polymer membranes differs substantially from the transport on analogous lipid networks. Specifically, our data suggest that polymer mobility in nanotubular structures is considerably different from planar or 3D structures, and is stunted by 1D confinement of the polymer subunits. Moreover, quantum dots adsorbed onto polymer nanotubes are completely immobile, which is related to this 1D confinement effect and is in stark contrast to the highly fluid transport observed on lipid tubules.

Defect passivation and tailoring of perovskite–charge transport layer interfaces are critical strategies to minimize the recombination losses and improve the power conversion efficiency (PCE) in perovskite solar cells (PSCs). Herein, we use titanium carbide MXene (Ti3C2T x ) to tailor the electronic properties of the electron transport layer (ETL) and ETL/perovskite interface in inverted (p–i–n) PSCs and correlate them to the observed PCE. MXene doping in a [6,6]-phenyl-C61-butyric acid methyl ester (M-PC61BM)-based ETL results in an improved electrical conductivity and ETL/perovskite interface band alignment. A red shift in the Ag(2) peak in the Raman spectrum and a localized upshift of the Fermi level calculated using scanning Kelvin probe force microscopy (SKPFM) confirm the n-doping of PC61BM. Consequently, PSC devices with M-PC61BM as the ETL show a higher PCE of 18% than PC61BM ETL-based control devices (PCE = 15.2%). Importantly, our study proves that the improvement in the open-circuit voltage (V OC) and fill factor (FF) depends on how MXene is integrated into the PSC, i.e., as a dopant in the PC61BM ETL, an interfacial layer between the perovskite and ETL, or a standalone ETL. Through comprehensive photoluminescence, electrochemical impedance spectroscopy, space-charge limited current, and scanning Kelvin probe force microscopy-based analyses, we establish that the introduction of MXene in PSCs has multiple benefits, including improvement in carrier transport, passivation and trap state reduction, and better interfacial energy alignment. Further, we unravel the most prominent factor influencing device performance in each mode of MXene introduction. Hence, the study reinforces the potential of Ti3C2T x MXene as a versatile material for high-performance electronic and optoelectronic devices.

Extremely high magnetic blocking temperatures (∼7.3 K) were observed for DyScS endohedral fullerene single-molecule magnets.