As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Polydopamine and Its Derivative Materials: Synthesis and Promising Applications in Energy, Environmental, and Biomedical Fields

Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform in which various physiochemical interactions with the encapsulated drugs control their release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel-drug interactions across the network, mesh, and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over the drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems, and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.

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Designing hydrogels for controlled drug delivery.

The combination of nanotechnology and molecular biology has developed into an emerging research area: nanobiotechnology. Magnetic nanoparticles are well-established nanomaterials that offer controlled size, ability to be manipulated externally, and enhancement of contrast in magnetic resonance imaging (MRI). As a result, these nanoparticles could have many applications in biology and medicine, including protein purification, drug delivery, and medical imaging. Because of the potential benefits of multimodal functionality in biomedical applications, researchers would like to design and fabricate multifunctional magnetic nanoparticles. Currently, there are two strategies to fabricate magnetic nanoparticle-based multifunctional nanostructures. The first, molecular functionalization, involves attaching antibodies, proteins, and dyes to the magnetic nanoparticles. The other method integrates the magnetic nanoparticles with other functional nanocomponents, such as quantum dots (QDs) or metallic nanoparticles. Because they can exhibit several features synergistically and deliver more than one function simultaneously, such multifunctional magnetic nanoparticles could have unique advantages in biomedical applications. In this Account, we review examples of the design and biomedical application of multifunctional magnetic nanoparticles. After their conjugation with proper ligands, antibodies, or proteins, the biofunctional magnetic nanoparticles exhibit highly selective binding. These results indicate that such nanoparticles could be applied to biological medical problems such as protein purification, bacterial detection, and toxin decorporation. The hybrid nanostructures, which combine magnetic nanoparticles with other nanocomponents, exhibit paramagnetism alongside features such as fluorescence or enhanced optical contrast. Such structures could provide a platform for enhanced medical imaging and controlled drug delivery. We expect that the combination of unique structural characteristics and integrated functions of multicomponent magnetic nanoparticles will attract increasing research interest and could lead to new opportunities in nanomedicine.

Multifunctional Magnetic Nanoparticles: Design, Synthesis, and Biomedical Applications

Control of stem cell fate by physical interactions with the extracellular matrix.

We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.

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Mussel-Inspired Surface Chemistry for Multifunctional Coatings

Mimicking Stem Cell Niches to Increase Stem Cell Expansion

Mimicking the in vivo stem cell niche to increase stem cell expansion will likely require the presentation of multiple ligands. Presenting ligands in fluid-supported lipid monolayers (SLMs) or bilayers (SLBs) allows for ligand diffusion to complement the arrangement of cell receptors as well as cell-mediated ligand rearrangement and clustering. Cells in tissues interact with ligands presented by other cells and the extracellular matrix (ECM), so it will likely be beneficial to present both cell-associated and ECM-derived ligands. A number of investigators have incorporated cell-membrane-associated ligands within fluid surfaces, and several groups have shown that these ligands cluster beneath the cells. However, few studies have investigated cell adhesion to ECM-derived ligands in fluid surfaces. Fibronectin is an important ECM component in many tissues, including the hematopoietic stem cell niche. We examined the adhesion of the M07e and THP-1 hematopoietic progenitor cell lines to fibronectin-derived pep...

Effects of Supported Lipid Monolayer Fluidity on the Adhesion of Hematopoietic Progenitor Cell Lines to Fibronectin-Derived Peptide Ligands for α5β1 and α4β1 Integrins

Background: Respiratory syncytial virus (RSV) vaccine is an unmet medical need. The virus reduction neutralization test (VRNT) was developed to replace the LI-COR microneutralization assay to measure RSV neutralization titers. Methods: A bridging study using selected V171 phase I samples and calibration studies using the WHO international standard antiserum to RSV were performed to compare VRNT and LI-COR. Results: From the bridging study, we showed good concordance between VRNT and LI-COR titers, and similar post-/pre-vaccination titer ratios. From the calibration studies, we can convert VRNT and LI-COR titers into similar IU/ml. Conclusion: The VRNT and LI-COR microneutralization assay correlate well and the titers can be standardized as similar IU/ml, enabling direct comparison of titers from different assays.

Virus reduction neutralization test and LI-COR microneutralization assay bridging and WHO international standard calibration studies for respiratory syncytial virus.

Shara M. Dellatore

Papers

Mussel-Inspired Surface Chemistry for Multifunctional Coatings

Mimicking Stem Cell Niches to Increase Stem Cell Expansion

Effects of Supported Lipid Monolayer Fluidity on the Adhesion of Hematopoietic Progenitor Cell Lines to Fibronectin-Derived Peptide Ligands for α5β1 and α4β1 Integrins

Virus reduction neutralization test and LI-COR microneutralization assay bridging and WHO international standard calibration studies for respiratory syncytial virus.