Nanomedicine is a promising strategy for improving clinical outcomes for cancer therapies, by improving drug efficacy through enhanced delivery to disease sites. It is of importance for ultimate ...clinical success to consider the contributing factors to achieving this goal, such as size, chemistry, and functionality of nanoparticle delivery systems, and how these parameters influence tumor localization and uptake. This Topical Review will first discuss the evolution and progress of nanoparticles for cancer drug delivery and the current challenges that remain to be addressed. Strategies for overcoming the limitations of passive targeting through active targeting approaches, and the current state of such nanomedicines in the clinic will be highlighted. Finally, novel approaches toward the design of active targeted nanoparticles building on our growing understanding of nanobio interactions are considered, in order to shed light on future design considerations for accelerating clinical translation of nanomedicines.
The past decades have seen significant research effort in the field of polymers for a range of biomedical applications, driven by the promising prospect of these materials for realizing next ...generation therapeutics in the clinic. In this regard, it is widely accepted that polymer properties such as chemistry, charge, and block composition, as well as properties of their self-assemblies including size, shape, surface chemistry, and biodegradation, all influence and direct their interactions with cells and biological membranes. In particular, polymer hydrophobicity is a property of interest, with growing evidence demonstrating the significant impact that hydrophobic interactions with lipid membranes and proteins can have on biomaterial application efficacy within the body. However, to date, this phenomenon has been relatively underexplored, and therefore there exists no clear universal understanding to direct polymer design. In this Perspective, we highlight important contributions to this field, focusing on seminal studies which investigate experimentally and theoretically how incorporation of hydrophobic moieties within polymer systems can influence their ultimate properties when used in biomedical applications. In this way, we aim to signify future directions in the design of highly performing polymers for biomedicine, making a case for the importance of standardized computational modeling to achieve widely applicable conclusions and facilitate future translational efforts.
Over the past few decades, advanced polymeric materials have gained popularity in the development of sustainable agricultural applications. Smart polymeric systems have extensively contributed to the ...agricultural industry by increasing the efficiency of pesticides, herbicides, and fertilizers by facilitating controlled release systems and, therefore, enabling lower doses to be used. Superabsorbent polymeric materials have been used as soil conditioners to control the impact of drought, whereas polycationic polymers have been utilized for plant bioengineering. These functions in the environment are complemented by applications within plants as part of the developing range of tools for genetically transforming plants in order to increase productivity and disease resistance. This Review will summarize and discuss the recent developments in the design and application of advanced polymeric systems for precision agriculture related applications. The design criteria of the polymers employed to date, such as polymer structure, as well as the properties of polymer nanoparticles including shape and size will be discussed, and the key findings in the related area will be highlighted. Finally, we will identify future directions for the exploration of functional polymers with the ultimate aim of advancing sustainable agriculture.
Polymer–drug conjugates have received considerable attention over the last decades due to their potential for improving the clinical outcomes for a range of diseases. It is of importance to develop ...methods for their preparation that have simple synthesis and purification requirements but maintain high therapeutic efficacy and utilize macromolecules that can be cleared via natural excretory pathways upon breakdown. Herein, the combination of ring‐opening polymerization (ROP) and reversible addition−fragmentation chain‐transfer (RAFT) polymerization is described for the straightforward synthesis of amphiphilic, stimuli‐responsive, biodegradable, and highly functionalizable hyperbranched polymers. These unimolecular nanoparticles demonstrate a versatile platform for the synthesis of polymer–drug conjugates owing to the inclusion of a Boc‐protected polycarbonate moiety in either a block or random copolymer formation. A proof‐of‐concept study on the complexation of the poorly water‐soluble antimicrobial drug usnic acid results in polymer‐drug complexes with powerful antimicrobial properties against gram‐positive bacteria. Therefore, this work highlights the potential of amphiphilic and biodegradable hyperbranched polymers for antimicrobial applications.
This work describes the combination of ring‐opening and reversible addition−fragmentation chain‐transfer polymerizations for the straightforward synthesis of amphiphilic, biodegradable, and highly functionalizable hyperbranched polymers. These unimolecular nanoparticles could complex the poorly water‐soluble antimicrobial drug usnic acid, resulting in polymer–drug complexes with powerful antimicrobial properties against gram‐positive bacteria, highlighting the potential of amphiphilic and biodegradable hyperbranched polymers for antimicrobial applications
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Shape and size play powerful roles in determining the properties of a material; controlling these aspects with precision is therefore an important, fundamental goal of the chemical sciences. In ...particular, the introduction of shape anisotropy at the nanoscale has emerged as a potent way to access new properties and functionality, enabling the exploration of complex nanomaterials across a range of applications. Recent advances in DNA and protein nanotechnology, inorganic crystallization techniques, and precision polymer self-assembly are now enabling unprecedented control over the synthesis of anisotropic nanoparticles with a variety of shapes, encompassing one-dimensional rods, dumbbells and wires, two-dimensional and three-dimensional platelets, rings, polyhedra, stars, and more. This has, in turn, enabled much progress to be made in our understanding of how anisotropy and particle dimensions can be tuned to produce materials with unique and optimized properties. In this Review, we bring these recent developments together to critically appraise the different methods for the bottom-up synthesis of anisotropic nanoparticles enabling exquisite control over morphology and dimensions. We highlight the unique properties of these materials in arenas as diverse as electron transport and biological processing, illustrating how they can be leveraged to produce devices and materials with otherwise inaccessible functionality. By making size and shape our focus, we aim to identify potential synergies between different disciplines and produce a road map for future research in this crucial area.
The seemingly simple notion of the hydrophobic effect can be viewed from multiple angles involving theory, simulation, and experiments. This viewpoint examines five attributes of predictive models to ...enhance synthetic efforts as well as experimental methods to quantify hydrophobicity. In addition, we compare existing predictive models against experimental data for polymer surface tension, lower critical solution temperature, solution self-assembly morphology, and degradation behavior. Key conclusions suggest that both the Hildebrand solubility parameters (HSPs) and surface area-normalized Log P (Log P SA–1) values provide unique and complementary insights into polymer phenomena. In particular, HSPs appear to better describe bulk polymer phenomena for thermoplastics such as surface tension, while Log P SA–1 values are well-suited for describing and predicting the behavior of polymers in solution.
The thermoresponsive behaviour of cross-linked poly(
N
-isopropylacrylamide) (pNIPAm) nanogels makes these materials particularly attractive for a variety of applications. Literature data report the ...use of different methodologies for preparing nanogels, which can be divided into heterogeneous and homogeneous polymerisation approaches. Heterogeneous polymerisation occurs above the volume phase transition temperature (VPTT) of pNIPAm due to water expulsion from the network of the forming polymer. On the contrary, homogeneous polymerisation is conducted below the VPTT, so that the nanogel is in the swollen state during the polymerisation process. Here, we study the effect of phase separation during polymerisation, which reveals a significant influence on the particle size and internal structure, as well as on the thermoresponsive and interfacial behaviour of pNIPAm nanomaterials. We propose that heterogeneous polymerisation leads to preferential localisation of hydrophilic initiator residues on the particle surface, while during homogeneous polymerisation, the initiator groups are distributed within the nanogel network. These results highlight the importance of the choice of polymerisation temperature as well as initiator for the synthesis of pNIPAm gels, as this significantly affects their characteristics and application.
The choice of the polymerisation temperature and initiator in the synthesis of poly(
N
-isopropylacrylamide)-based nanogels can significantly influence their structure, morphology and thermoresponsive properties.
Polymersomes are a class of synthetic vesicles composed of a polymer membrane surrounding an aqueous inner cavity. In addition to their overall size, the thickness and composition of polymersome ...membranes determine the range of potential applications in which they can be employed. While synthetic polymer chemists have made great strides in controlling polymersome membrane parameters, measurement of their permeability to various analytes including gases, ions, organic molecules, and macromolecules remains a significant challenge. In this Outlook, we compare the general methods that have been developed to quantify polymersome membrane permeability, focusing in particular on their capability to accurately measure analyte flux. In addition, we briefly highlight strategies to control membrane permeability. Based on these learnings, we propose a set of criteria for designing future methods of quantifying membrane permeability such that the passage of a variety of molecules into and out of their lumens can be better understood.
Hydrogels based on biopolymers, such as alginate, are commonly used as scaffolds in tissue engineering applications as they mimic the features of the native extracellular matrix (ECM). However, in ...their native state, they suffer from drawbacks including poor mechanical performance and a lack of biological functionalities. Herein, we have exploited a crystallization-driven self-assembly (CDSA) methodology to prepare well-defined one-dimensional micellar structures with controlled lengths to act as a mimic of fibrillar collagen in native ECM and improve the mechanical strength of alginate-based hydrogels. Poly(ε-caprolactone)-b-poly(methyl methacrylate)-b-poly(N, N-dimethyl acrylamide) triblock copolymers were self-assembled into 1D cylindrical micelles with precise lengths using CDSA epitaxial growth and subsequently combined with calcium alginate hydrogel networks to obtain nanocomposites. Rheological characterization determined that the inclusion of the cylindrical structures within the hydrogel network increased the strength of the hydrogel under shear. Furthermore, the strain at flow point of the alginate-based hydrogel was found to increase with nanoparticle content, reaching an improvement of 37% when loaded with 500 nm cylindrical micelles. Overall, this study has demonstrated that one-dimensional cylindrical nanoparticles with controlled lengths formed through CDSA are promising fibrillar collagen mimics to build ECM scaffold models, allowing exploration of the relationship between collagen fiber size and matrix mechanical properties.
Analysis of social media using digital methods is a flourishing approach. However, the relatively easy availability of data collected via platform application programming interfaces has arguably led ...to the predominance of single-platform research of social media. Such research has also privileged the role of text in social media analysis, as a form of data that is more readily gathered and searchable than images. In this paper, we challenge both of these prevailing forms of social media research by outlining a methodology for visual cross-platform analysis (VCPA), defined as the study of still and moving images across two or more social media platforms. Our argument contains three steps. First, we argue that cross-platform analysis addresses a gap in research methods in that it acknowledges the interplay between a social phenomenon under investigation and the medium within which it is being researched, thus illuminating the different affordances and cultures of web platforms. Second, we build on the literature on multimodal communication and platform vernacular to provide a rationale for incorporating the visual into cross-platform analysis. Third, we reflect on an experimental cross-platform analysis of images within social media posts (n = 471,033) used to communicate climate change to advance different modes of macro- and meso-levels of analysis that are natively visual: image-text networks, image plots and composite images. We conclude by assessing the research pathways opened up by VCPA, delineating potential contributions to empirical research and theory and the potential impact on practitioners of social media communication.
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