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Transdermal microneedles have captured the attention of researchers in relation to a variety of applications, and silicone-based molds required to produce these systems are now widely available and can be readily manufactured on the lab bench. The production of nanocomposite microneedle arrays through micromolding techniques is described. The formulation of nanoparticulate carbon along with pH sensitive cellulose acetate phthalate as a polymeric binder is shown to produce conductive microneedles whose swelling/dissolution properties can be controlled electrochemically. Through exploiting hydrogen evolution at the microneedle array, changes in local pH can induce swelling within the needle structure and could lay the foundations for a new approach to the smart device controlled delivery of therapeutic agents. The surface modification of the carbon needles with palladium and cysteine is critically assessed from sensing and drug delivery perspectives.

Catheter related blood stream infection is an ever present hazard for those patients requiring venous access and particularly for those requiring long term medication. The implementation of more rigorous care bundles and greater adherence to aseptic techniques have yielded substantial reductions in infection rates but the latter is still far from acceptable and continues to place a heavy burden on patients and healthcare providers. While advances in engineering design and the arrival of functional materials hold considerable promise for the development of a new generation of catheters, many challenges remain. The aim of this review is to identify the issues that presently impact catheter performance and provide a critical evaluation of the design considerations that are emerging in the pursuit of these new catheter systems.

Electrochemical anodisation techniques are regularly used to modify carbon fiber surfaces as a means of improving electrochemical performance. A detailed study of the effects of oxidation (+ 2 V) in alkaline media has been conducted and Raman, XPS and SEM analyses of the modification process have been tallied with the resulting electrochemical properties. The co-application of ultrasound during the oxidative process has also been investigated to determine if the cavitational and mass transport features influence both the physical and chemical nature of the resulting fibers. Marked discrepancies between anodisation with and without ultrasound is evident in the C1s spectra with variations in the relative proportions of the electrogenerated carbon-oxygen functionalities. Mechanisms that could account for the variation in surface species are considered. Graphic abstract

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