Light-induced Patterning of Electroactive Bacterial Biofilms

Electroactive bacterial biofilms can function as living biomaterials that merge the functionality of living cells with electronic components. However, the development of such advanced living electronics has been challenged by the inability to control the geometry of electroactive biofilms relative to solid-state electrodes. Here, we developed a lithographic strategy to pattern conductive biofilms of Shewanella oneidensis by controlling aggregation protein CdrAB expression with a blue light-induced genetic circuit. This controlled deposition enabled S. oneidensis biofilm patterning on transparent electrode surfaces and measurements demonstrated tunable biofilm conduction dependent on pattern size. Controlling biofilm geometry also enabled us, for the first time, to quantify the intrinsic conductivity of living S. oneidensis biofilms and experimentally confirm predictions based on simulations of a recently proposed collision-exchange electron transport mechanism. Overall, we developed a facile technique for controlling electroactive biofilm formation on electrodes, with implications for both studying and harnessing bioelectronics.

Hybrid Supercapacitor Electrode Materials via Molecular Imprinting of Nitrogenous Ligands and Iron Complexes into Carbon Support

Novel hybrid supercapacitor materials were made by the covalent immobilization of nitrogenous ligands onto the surface of commercial carbon support (Vulcan XC-72), then coordinated to iron. The covalent attachment of the nitrogenous ligands allows for the controlled deposition of nitrogen functionalities on the surface of the carbon. The supercapacitor tests in acidic media showed significant growth of the capacitance as a result of the nitrogenous ligands on the support. Notably, the increase of the capacitance values directly correlates with the molecular loading on the surface. Following coordination of the iron to the ligands on the surface further elevated the capacitance via Faradaic reactions of the metal center. Remarkably, the overall capacitance of materials significantly increased after the course of long-term cycling tests (ca. 110% or higher). At the beginning of durability studies, a small decline in capacitance was observed, due to some extent of molecular decomposition on the surface of the electrode. However, the intense cycling further propagates a steady growth of the overall capacitance. This could be attributed to the process of polymerization of physisorbed molecules/ radicals that result in the formation of a 3D network structure that eventually boosts the overall capacitance and charge storage of the electrode.

Wide Range Responsivity Photodetector of Zr-Au-Ag Oxide NPs Prepared By Pulsed Laser Ablation

Metal-ceramic composite particles are of increasing interest due to their potential applications in photodetectors as well as next-generation catalysts. The zirconium-gold system has received little attention due to the lack of controllable preparation methods. Well-known methods for the deposition of gold Nano shells on zirconium spheres, however, should be adaptable for similar zirconium-based materials. Here, we present a method to synthetic approach to the well-controlled deposition of gold on the surface by laser ablation. The results shed light on the parameters governing the preparation of zirconium _ gold composite particles and our synthetic approach provides a promising tool for future developments in complex nanomaterials design. As well as studying the structural and optical properties of gold, silver and zirconium nanoparticles by preparing those particles in the above method and studying the properties of the resulting materials as a photodetector. The surface morphology, structure, and composition of the layer were studied using a variety of spectroscopic diffraction and real-space imaging techniques, including SEM, EDX and AFM.

Combining Nanotechnology and Gas Plasma as an Emerging Platform for Cancer Therapy: Mechanism and Therapeutic Implication

Nanomedicine and plasma medicine are innovative and multidisciplinary research fields aiming to employ nanotechnology and gas plasma to improve health-related treatments. Especially cancer treatment has been in the focus of both approaches because clinical response rates with traditional methods that remain improvable for many types of tumor entities. Here, we discuss the recent progress of nanotechnology and gas plasma independently as well as in the concomitant modality of nanoplasma as multimodal platforms with unique capabilities for addressing various therapeutic issues in oncological research. The main features, delivery vehicles, and nexus between reactivity and therapeutic outcomes of nanoparticles and the processes, efficacy, and mechanisms of gas plasma are examined. Especially that the unique feature of gas plasma technology, the local and temporally controlled deposition of a plethora of reactive oxygen, and nitrogen species released simultaneously might be a suitable additive treatment to the use of systemic nanotechnology therapy approaches. Finally, we focus on the convergence of plasma and nanotechnology to provide a suitable strategy that may lead to the required therapeutic outcomes.

Electrochemical and photoluminescence response of laser-induced graphene/electrodeposited ZnO composites

The inherent scalability, low production cost and mechanical flexibility of laser-induced graphene (LIG) combined with its high electrical conductivity, hierarchical porosity and large surface area are appealing characteristics for many applications. Still, other materials can be combined with LIG to provide added functionalities and enhanced performance. This work exploits the most adequate electrodeposition parameters to produce LIG/ZnO nanocomposites. Low-temperature pulsed electrodeposition allowed the conformal and controlled deposition of ZnO rods deep inside the LIG pores whilst maintaining its inherent porosity, which constitute fundamental advances regarding other methods for LIG/ZnO composite production. Compared to bare LIG, the composites more than doubled electrode capacitance up to 1.41 mF cm−2 in 1 M KCl, while maintaining long-term cycle stability, low ohmic losses and swift electron transfer. The composites also display a luminescence band peaked at the orange/red spectral region, with the main excitation maxima at ~ 3.33 eV matching the expected for the ZnO bandgap at room temperature. A pronounced sub-bandgap tail of states with an onset absorption near 3.07 eV indicates a high amount of defect states, namely surface-related defects. This work shows that these environmentally sustainable multifunctional nanocomposites are valid alternatives for supercapacitors, electrochemical/optical biosensors and photocatalytic/photoelectrochemical devices.

Electrochemical and Photoluminescence Response of Laser-induced Graphene/Electrodeposited ZnO Composites

The inherent scalability, low production cost and mechanical flexibility of laser-induced graphene (LIG) combined with its high electrical conductivity, hierarchichal porosity and large surface area are appealing characteristics for many applications. Still, other materials can be combined with LIG to provide added functionalities and enhanced performance. This work exploits the most adequate electrodeposition parameters to produce LIG/ZnO nanocomposites. Low-temperature pulsed electrodeposition allowed the conformal and controlled deposition of ZnO rods deep inside the LIG pores whilst maintaining its inherent porosity, which constitute fundamental advances regarding other methods for LIG/ZnO composite production. Compared to bare LIG, the composites more than doubled electrode capacitance up to 1.41 mF.cm-2 in 1 M KCl, whilst maintaining long-term cycle stability, low ohmic losses and swift electron transfer. The composites also display a luminescence band peaked at the orange/red spectral region, with main excitation maxima at ~3.33 eV matching the expected for the ZnO bandgap. A pronounced sub-bandgap tail of states with an onset absorption near 3.07 eV indicates a high amount of surface states. This work shows that these environmentally sustainable multifunctional nanocomposites are valid alternatives for supercapacitors, electrochemical/optical biosensors and photocatalytic/photoelectrochemical devices.