Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

https://iopscience.iop.org/article/10.1088/0957-4484/22/29/292001/pdf

Nanostructured materials for water desalination.

One strategy in modern medicine is the development of new platforms that combine multifunctional compounds with stable, safe carriers in patient-oriented therapeutic strategies. The simultaneous detection and treatment of pathological events through interactions manipulated at the molecular level offer treatment strategies that can decrease side effects resulting from conventional therapeutic approaches. Several types of nanocarriers have been proposed for biomedical purposes, including inorganic nanoparticles, lipid aggregates, including liposomes, and synthetic polymeric systems, such as vesicles, micelles, or nanotubes.Polymeric vesicles—structures similar to lipid vesicles but created using synthetic block copolymers—represent an excellent candidate for new nanocarriers for medical applications. These structures are more stable than liposomes but retain their low immunogenicity. Significant efforts have been made to improve the size, membrane flexibility, and permeability of polymeric vesicles and to ...

Polymeric vesicles: from drug carriers to nanoreactors and artificial organelles.

Biological membranes play an essential role in living organisms by providing stable and functional compartments, preserving cell architecture, whilst supporting signalling and selective transport that are mediated by a variety of proteins embedded in the membrane. However, mimicking cell membranes – to be applied in artificial systems – is very challenging because of the vast complexity of biological structures. In this respect a highly promising strategy to designing multifunctional hybrid materials/systems is to combine biological molecules with polymer membranes or to design membranes with intrinsic stimuli-responsive properties. Here we present supramolecular polymer assemblies resulting from self-assembly of mostly amphiphilic copolymers either as 3D compartments (polymersomes, PICsomes, peptosomes), or as planar membranes (free-standing films, solid-supported membranes, membrane-mimetic brushes). In a bioinspired strategy, such synthetic assemblies decorated with biomolecules by insertion/encapsulation/attachment, serve for development of multifunctional systems. In addition, when the assemblies are stimuli-responsive, their architecture and properties change in the presence of stimuli, and release a cargo or allow “on demand” a specific in situ reaction. Relevant examples are included for an overview of bioinspired polymer compartments with nanometre sizes and membranes as candidates in applications ranging from drug delivery systems, up to artificial organelles, or active surfaces. Both the advantages of using polymer supramolecular assemblies and their present limitations are included to serve as a basis for future improvements.

/pdf/bioinspired-polymer-vesicles-and-membranes-for-biological-3d546sxrk4.pdf

Bioinspired polymer vesicles and membranes for biological and medical applications

https://www.materialstoday.com/download/50891/

Block copolymer nanostructures

Emerging Applications of Polymersomes in Delivery: from Molecular Dynamics to Shrinkage of Tumors.

Functional groups and their associated charges are responsible for the binding and release of molecules from the surfaces of particles in nanodiamond colloids. In this work, we describe a combined set of experimental and computational techniques that are used to characterize these functional groups quantitatively. The surfaces of the particles examined during this study are amphoteric, as one would expect for surfaces made of carbon, with high concentrations of phenols, pyrones, and sulfonic acid groups; the average 50-nm-diameter nanodiamond aggregate has approximately 22000 phenols, 7000 pyrones, and 9000 sulfonic acids. The aggregates also have at least 2000 fixed positive charges, stabilized within pyrones and/or chromenes. No evidence for a significant concentration of carboxylic acid groups was found, although some are probably present. Hydroxyl and epoxide groups are present on some areas of the surfaces. The surfaces are graphitized, so the presence of phenols and pyrones is not surprising because...

Understanding the Surfaces of Nanodiamonds

Block copolymer-based membrane technology enables the development of a versatile class of nanoscale materials in which biomolecules, such as membrane proteins, can be reconstituted. These active materials possess a broad applicability in areas such as the enhancement of existing technologies or production of current-generating films for power sources. For example, these active materials can be integrated with fuel cell ion transport membranes such as Nafion® in order to improve the ability of Nafion® to retain leaking protons. Also, the demonstration of protein-driven current production across these membranes represents a possible alternative power source that is both highly efficient and light in weight. Our work has demonstrated the fabrication of large-area copolymer biomembranes that are functionalized by bacteriorhodopsin (BR) and cytochrome c oxidase (COX) ion transport proteins. Among their many advantages over conventional lipid-based membrane systems, block copolymers can mimic natural cell biomembrane environments in a single chain, enabling large-area membrane fabrication using methods such as Langmuir–Blodgett (LB) deposition. Following the large-scale insertion of proteins into block copolymer LB films, we have demonstrated significant pH changes based upon light-actuated proton pumping. Protein activity across the BR and COX-functionalized membrane has also been observed using impedance spectroscopy as well as direct current measurement.

https://iopscience.iop.org/article/10.1088/0957-4484/15/8/038/pdf

Protein-driven energy transduction across polymeric biomembranes

Magnetic nanomaterials with multimodal functionalities have emerged as a versatile platform for biomedical applications that range from basic cellular interrogation to clinical nanomedicine. In this work, we have prepared electrodeposited ferromagnetic nickel nanowires for efficient internalization into 3T3 fibroblasts. Agitation of the nanowires by a low external field induced cell death, as assessed by MTT viability assays. The response of the interleukin-6 (IL-6) gene expression of the fibroblasts to nanowire-mediated cellular manipulation was examined by quantitative real-time polymerase chain reaction (qRT-PCR). These nanowires exhibited significant potential as therapeutic and interrogative platforms for biomedicine.

Induction of Cell Death by Magnetic Actuation of Nickel Nanowires Internalized by Fibroblasts

Protein-functionalized polymers retain dramatically increased stability over lipid membranes and the unique ability to be deposited on solid substrates in the ABA complex. Furthermore, since these polymers can mimic hydrophilic/hydrophobic biological environments in a single molecular chain, direct adsorption of protein-functionalized biomembrane films is enabled, which is a significant advantage over conventional lipid systems. Following the demonstration of protein mutagenesis and nanoscale biomimetic membrane fabrication, monolayer arrays of pore proteins have been deposited onto silicon wafers for applications in sensing nanomolecules such as conjugated quantum dots and colloidal gold beads. Furthermore, we have characterized monolayer surface properties of custom tailored polymers with varied block length for biomimetic membrane applications, as well as developed a multiwell microelectromechanical-system-based membrane testing platform for enhanced versatility in film deposition. We have successfully demonstrated the reconstitution of a genetically engineered OmpF porin in block copolymer-based biomembranes, fabrication of large-area hybrid protein-polymer Langmuir-Blodgett films, as well as protein insertion via macromolecule detection using protein-polymer active materials with the goal of buildup toward a multicomponent microsystem while preserving inherent molecular function.

Hybrid protein-polymer biomimetic membranes

This work demonstrates the integration of the energy-transducing proteins bacteriorhodopsin (BR) from Halobacterium halobium and cytochrome c oxidase (COX) from Rhodobacter sphaeroides into block copolymeric vesicles towards the demonstration of coupled protein functionality. An ABA triblock copolymer-based biomimetic membrane possessing UV-curable acrylate endgroups was synthesized to serve as a robust matrix for protein reconstitution. BR-functionalized polymers were shown to generate light-driven transmembrane pH gradients while pH gradient-induced electron release was observed from COX-functionalized polymers. Cooperative behaviour observed from composite membrane functionalized by both proteins revealed the generation of microamp-range currents with no applied voltage. As such, it has been shown that the fruition of technologies based upon bio-functionalizing abiotic materials may contribute to the realization of high power density devices inspired by nature.

/pdf/fabrication-of-biomolecule-copolymer-hybrid-nanovesicles-as-2w5cmpv1v8.pdf

Dean Ho

Papers

Understanding the Surfaces of Nanodiamonds

Protein-driven energy transduction across polymeric biomembranes

Induction of Cell Death by Magnetic Actuation of Nickel Nanowires Internalized by Fibroblasts

Hybrid protein-polymer biomimetic membranes

Fabrication of biomolecule–copolymer hybrid nanovesicles as energy conversion systems