Barriers to therapeutic transport in biological systems can prevent accumulation of drugs at the intended site, thus limiting the therapeutic effect against various diseases. Advances in synthetic chemistry techniques have recently increased the accessibility of complex polymer architectures for drug delivery systems, including branched polymer architectures. This article first outlines drug delivery concepts, and then defines and illustrates all forms of branched polymers including highly branched polymers, hyperbranched polymers, dendrimers, and branched–linear hybrid polymers. Many new types of branched and dendritic polymers continue to be reported; however, there is often confusion about how to accurately describe these complex polymer architectures, particularly in the interdisciplinary field of nanomedicine where not all researchers have in‐depth polymer chemistry backgrounds. In this context, the present review describes and compares different branched polymer architectures and their application in therapeutic delivery in a simple and easy‐to‐understand way, with the aim of appealing to a multidisciplinary audience.

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.

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Sébastien. (2016) Hyperbranched polymers with high degrees of branching and low dispersity values : pushing the limits of thiol-yne chemistry. Macromolecules, 49 (4). pp. 1296-1304. Permanent WRAP URL:http://wrap.warwick.ac.uk/83847 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher.To access the final edited and published work see http://dx.doi.org/10.1021/acs.macromol.6b00132 A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription.

to the surface of the liquid and rapidly oxidizes forming oxides and suboxides of Ga with some hydroxyls present. The instantaneous oxide formation on GaLMAs provides unmatched capabilities to create self-supporting liquid structures in free space [14,15] and prevent material loss in the case of a microchannel damage [6] unlike any other class of fluids. The oxide skin also enables the liquid to remain within small diameter, high aspect ratio microchannels [15] at ambient pressure and does not contribute noticeably to the interface resistance between the liquid metal and solid electrical contacts. [16] While the rapid oxidation of GaLMA surfaces can be extremely advantageous, the lack of control over this reactive gallium interface has been the primary cause of the fluids' poor implementation into flexible and reconfigurable electronics. The two critical obstacles are as follows:1. GaLMAs tend to be very "sticky" because the surface oxide adheres to various substrates [17] and microchannel walls, [18] resulting in deposition of fluid onto random surface areas and in detrimental locations. 2. Gallium aggressively alloys with every metal used in electronics, [19] resulting in unwanted phase transitions, embrittlement of solid metal circuitry, and general lack of control of fluid location.The main approach reported to date to circumvent the negative "sticky" effects of the GaLMA fluids has been to use strong acids or bases to continuously etch away the oxide skin. [17,18] While these methods have resulted in temporary removal of the "sticky oxide" problem, they have not yet led to practical integration of GaLMAs into useful applications for several reasons. In addition to introducing highly corrosive materials into an otherwise benign system, etching away the oxide forfeits all the beneficial attributes of GaLMAs detailed above. While under normal circumstances the diffusion of gallium into solid metals is slow (obstacle #2 above), the acidic or basic environment substantially accelerates this diffusion process. Other approaches have shown that water can provide a slip layer to enable GaLMA movement, [20] however residue still builds up over time as seen by our group and others. To prevent the diffusion of gallium into other solid metal contacts, barrier layers are needed, introducing additional contact resistive losses and processing steps. [19,21] Better rheological control of the liquid Gallium liquid metal alloys are room temperature fluidic conductors that are used to create a variety of paradigm shifting concepts in stretchable and reconfigurable electronics. A viscoelastic solid oxide skin encases the bulk liquid metal alloy which allows remarkably unprecedented 3D fluidic structures to be constructed. This oxide also has detrimental effects to fluidic behavior in microchannels because it adheres to the channel walls. The work mitigates these detrimental effects in flow behavior through surface modification of the gallium oxide with phosphonic acids to control interfacial chemistry. This results in no adhesio...

Gallium-based metal alloys have high electrical conductivity in the liquid state at room temperature. These liquid metal conductors inspire unique electronic applications such as reconfigurable circuits and stretchable components with extremely high strain tolerance. Previously, liquid metals have been successfully patterned via direct-writing, yielding metallically conductive features on-demand at room temperature that do not require post-processing, down to a resolution of %10 μm. While most direct-write processes extrude materials from a nozzle via pressure or volumetric displacement, liquid metal is instead printed here by a shear-driven mechanism that occurs when the oxide-coated meniscus of the metal adheres to the printing substrate and is "pulled" from the nozzle at pressures that are well-below that needed to extrude the metal in the absence of shear. Herein, the key operating parameters that enable shear-driven printing of liquid metals including dispensing pressure, choice of substrate, print height, the surrounding environmental conditions, and the speed and acceleration of the print head are elucidated. A guide to the best practices as well as limitations for implementing shear-driven printing of liquid metals at room temperature is provided in these studies.

The complexation and sustained release of dsRNA from highly branched polymers prepared via RAFT polymerisation and copolymerisation of the monomers DMAEA, DMAPA, and DMAEMA, is reported.

Synthesis of long-chain hyperbranched poly(ethylenimine-co-oxazoline)s by AB2 thiol–yne chemistry is reported, and their application as pDNA transfection agents studied.