This version is available at https://strathprints.strath.ac.uk/59696/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. conditions. The results shown here pave the way for using the proposed methodology to discern the role of target enzymes in intracellular signaling pathways. 3Enzymes are biological catalysts involved in crucial cellular processes such as signaling pathways, DNA replication, and protein expression. In biotechnology, enzymes are used for manufacturing biosensors, [1] medicines, [2] fuels [3] and foodstuffs. [4] A methodology for inactivating a target enzyme on demand could be useful for discerning the role of the biocatalyst in a particular cell function. [5] A light-triggered inactivation mechanism would be ideal for these applications since it would enable turning off the enzyme activity noninvasively and on demand. Current methods for controlling the activity of enzymes with light require the synthesis of photoresponsive enzyme substrates, i.e. a molecule that changes its conformation upon irradiation at a particular wavelength. [6] While this approach allows a fine control over the activity of a given enzyme, it can only be applied to those enzymes whose substrate can be synthesized in a laboratory. Furthermore, enzymes show exquisite specificity for the conversion of a particular substrate. This means that different lightresponsive molecules must be synthesized for each specific enzyme, which is very timeconsuming. Moreover, supplying synthetic substrates may be cumbersome in intracellular or in vivo studies, in which the photoresponsive molecules may need to permeate cell membranes and compete with naturally occurring substrates in order to inactivate the enzymes. In this context it would be highly desirable to find a generic methodology that allowed inactivating any target enzyme remotely regardless of its substrate specificity and in different biological scenarios, such as in the presence of other enzym...

Gold nanorods (NRs) have attracted a great deal of interest for a variety of biomedical and sensing applications. However, developing robust methods for biofunctionalizing NRs has continued to be challenging, especially for NR-DNA conjugates. This is due to the presence of cetyltrimethylammonium bromide (CTAB), which plays an essential role in controlling the anisotropic particle growth. In this article, we systematically explore the growth of a polydopamine (PDA) layer on a range of NR surfaces, comparing different polyelectrolyte and alkanethiol coatings as well as direct CTAB displacement. This revealed that the PDA layer thickness and growth rate is strongly dependent on the underlying nanorod functionalization chemistry and allowed us to establish a preferred route for the creation of stable, non-aggregated suspensions of PDA-coated NRs. The utility of this platform was then demonstrated by self-assembling packed monolayers of single-stranded DNA on the outer surface. Both the surface attachment and bioactivity of the resulting NR-DNA conjugates was then demonstrated by performing bulk solution and single nanoparticle imaging fluorescence measurements.

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