An improved method to convert nitrogen to nitrogen-vacancy (NV) color centers in diamond has been reported by CNBP researchers in a paper published in the journal Carbon. Lead author of the paper was CNBP student Marco Capelli (pictured).
Authors: M. Capelli, A.H. Heffernan, T. Ohshima, H. Abe, J. Jeske, A. Hope, A.D. Greentree, P. Reineck, B.C. Gibson.
Abstract: The nitrogen-vacancy (NV) centre is a fluorescent defect in diamond that is of critical importance for applications from ensemble sensing to biolabelling. Hence, understanding and optimising the creation of NV centres in diamond is vital for technological progress in these areas. We demonstrate that simultaneous
electron irradiation and annealing of a high-pressure high-temperature diamond sample increases the NV centre creation efficiency from substitutional nitrogen defects by up to 117 % with respect to a sample where the processes are carried out consecutively, but using the same process parameters. This increase in fluorescence is supported by visible and infrared absorption spectroscopy experiments. Our results pave the way for a more efficient creation of NV centres in diamond as well as higher overall NV densities in the future.
A new CNBP research publication (lead author Dr Roman Kostecki, University of Adelaide) describes how molecular interactions can be modulated by defining the local nano-environment to give a specific chemical outcome.
Journal: ACS Applied Materials and Interfaces.
Publication title: Control of Molecular Recognition via Modulation of the Nanoenvironment.
Authors: Roman Kostecki, Sabrina Heng, Adrian M. Mak, Heike Ebendorff-Heidepriem, Tanya M. Monro, and Andrew D. Abell.
Abstract: Many biological processes are driven by the interaction of a host with a guest molecule. We show such interactions can be modulated by carefully defining the local molecular environment to give a specific chemical outcome. Particularly, the selectivity of a host toward two different ions (Ca2+ and Al3+) is defined by it being in solution or the physisorbed state. In solution, the host displays greater selectivity toward Ca2+. When physisorbed, the selectivity profile of the host is reversed with enhanced binding of Al3+. This demonstrates a single host molecule can be tailored to selectively bind multiple guests by altering its nanoenvironment.
An immunosensor created on an optical fiber surface has been developed by CNBP researchers that has successfully detected cytokine proteins in a rat’s spinal cord. The result indicates that such fiber sensors can be used as an effective and sensitive tool for localised detection of cytokines in vivo, in a range of research and clinical applications. Lead author on the published research paper was CNBP’s Kaixin Zhang.
Journal: Sensors and Actuators B: Chemical.
Publication title: An optical fiber based immunosensor for localized detection of IL-1 in rat spinal cord.
Authors: Kaixin Zhang, Azim Arman, Ayad G. Anwer, Mark R. Hutchinson, Ewa M. Goldys.
Abstract: Sensitive and localized measurements of cytokines is important in biomedicine as cytokines are produced locally where needed to induce an immune reaction. Here, we present a novel immunosensor deposited on the optical fiber surface. The sensor is capable of localized detection of interleukin-1beta (IL-1β) in the rat spinal cord. In this immunosensor, a stable immunocapture surface was formed via a biotin-streptavidin coupling strategy and fluorescent carboxylated supermagnetic iron oxide (SPIO)-IL-1β detection antibody conjugates were used for signal amplification. Under the optimal condition, the proposed immunosensor can be used for the estimation of IL-1β in vitro in the range from 3.13 pg.mL-1 to 400 pg.mL-1 with a detection limit of 1.12 pg.mL-1. Furthermore, the performance of the fiber sensor was firstly assessed by ex-vivo monitoring the secretions of the rat macrophages stimulated by lipopolysaccharide (LPS), and the results demonstrated significant correlations with a commercial ELISA kit. Furthermore, the fiber sensor was successfully utilized to carry out a localized measurement of IL-1β in a spinal cord of an anesthetized rat. The result indicates that such fiber sensors can be used as an effective and sensitive tool for localised detection of IL-1β in vivo, in a range of research and clinical applications.
CNBP researchers have published a new science paper reporting on a new zinc responsive delivery system with real-time intracellular sensing capabilities. Lead author of the publication is Dr Sabrina Heng (pictured).
Authors: Sabrina Heng, Xiaozhou Zhang, Jinxin Pei, Alaknanda Adwal, Philipp Reineck, Brant Gibson, Mark Hutchinson, Andrew Abell.
Abstract: A new spiropyran‐based stimuli‐responsive delivery system is presented that encapsulates and then releases an extraneous compound in response to elevated levels of Zn2+, a critical factor in cell apoptosis. A C12‐alkyl substituent on the spiropyran promotes self‐assembly into a micelle‐like nanocarrier in aqueous media, with nanoprecipitation and encapsulation of added payload. Zn2+ binding occurs to an appended bis(2‐pyridylmethyl)amine group at biologically relevant micromolar concentration. This leads to switching of the spiropyran (SP) isomer to the strongly fluorescent ring opened merocyanine‐Zn2+ (MC‐Zn2+) complex, with associated expansion of the nanocarriers to release the encapsulated payload. Payload release is demonstrated in solution and in HEK293 cells by encapsulation of a blue fluorophore, 7‐hydroxycoumarin, and monitoring its release using fluorescence spectroscopy and microscopy. Furthermore, we demonstrate the use of the nanocarriers to deliver a caspase inhibitor, Azure B, into apoptotic cells in response to an elevated Zn2+ concentration. This then inhibits intracellular caspase activity, as evidenced by confocal microscopy and in real‐time by time‐lapsed microscopy. Finally, the nanocarriers are shown to release an encapsulated proteasome inhibitor (5) in Zn2+‐treated breast carcinoma cell line models. This then inhibits intracellular proteasome and induces cytotoxicity to the carcinoma cells.