Imperial College London

PROFESSOR NICHOLAS LONG

Faculty of Natural SciencesDepartment of Chemistry

Sir Edward Frankland BP Chair -Inorganic Chemistry
 
 
 
//

Contact

 

+44 (0)20 7594 5781n.long Website CV

 
 
//

Location

 

501jMolecular Sciences Research HubWhite City Campus

//

Summary

 

Publications

Publication Type
Year
to

243 results found

Mundil R, Wilson LE, Schaarschmidt D, Císařová I, Merna J, Long NJet al., 2019, Redox-switchable α-diimine palladium catalysts for control of polyethylene topology, Polymer, Vol: 179, Pages: 121619-121619, ISSN: 0032-3861

Journal article

Wang L, Long NJ, Li L, Lu Y, Li M, Cao J, Zhang Y, Zhang Q, Xu S, Yang Z, Mao C, Peng Met al., 2019, Multi-functional bismuth-doped bioglasses: combining bioactivity and photothermal response for bone tumor treatment and tissue repair (vol 7, 1, 2018), LIGHT-SCIENCE & APPLICATIONS, Vol: 8, ISSN: 2047-7538

Journal article

Miller P, Apps S, Long N, 2019, Cobalt(-I) triphos dinitrogen complexes: activation and silyl-functionalisation of N2, Chemical Communications, Vol: 55, Pages: 6579-6582, ISSN: 1359-7345

The cobalt dinitrogen complexes [{(EP3Ph)Co(μ-N2)}2Mg(THF)4], with triphos ligand scaffolds (EP3Ph, E = N or CMe), were prepared via two electron reductions of the Co(I) precursors [CoCl(EP3Ph)]. Both complexes showed high degrees of N2 activation owing to the formation of a rare M–NN–Mg–NN–M bridging-magnesium core. These systems showed further N2 functionalisation reactivity by silylation, forming silyldiazenido complexes [(EP3Ph)Co(NNSiMe3)].

Journal article

Hernandez-Gil J, Braga M, Harriss B, Carroll LS, Leow CH, Tang M-X, Aboagye EO, Long NJet al., 2019, Development of Ga-68-labelled ultrasound microbubbles for whole-body PET imaging, CHEMICAL SCIENCE, Vol: 10, Pages: 5603-5615, ISSN: 2041-6520

Journal article

McCluskey S, Haslop A, Coello C, Gunn R, Tate E, Southworth R, Plisson C, Long NJ, Wells Let al., 2019, Imaging chemotherapy induced acute cardiotoxicity with 18F-labelled lipophilic cations, Journal of Nuclear Medicine, ISSN: 1535-5667

Many chemotherapy agents are toxic to the heart, such that increasing numbers of cancer survivors are now living with the potentially lethal cardiovascular consequences of their treatment. Earlier and more sensitive detection of chemotherapy-induced cardiotoxicity may allow improved treatment strategies and increase long-term survival. Lipophilic cation positron emission tomography (PET) tracers may be suitable for early detection of cardiotoxicity. This study aims to evaluate an 18F-labelled lipophilic phosphonium cation e.g. 18F-Mitophos, as a cardiac imaging agent, comparing it to leading PET and SPECT lipophilic cationic tracers before further assessing its potential for imaging cardiotoxicity in an acute doxorubicin (DOX) model.

Journal article

Mann PB, Afzal K, Long NJ, Thanou M, Green Met al., 2019, A glassware- free combinatorial synthesis of green quantum dots using bubble wrap, RSC ADVANCES, Vol: 9, Pages: 16851-16855, ISSN: 2046-2069

Journal article

Morse SV, Pouliopoulos AN, Chan TG, Copping MJ, Lin J, Long NJ, Choi JJet al., 2019, Rapid short-pulse ultrasound delivers drugs uniformly across the murine blood-brain barrier with negligible disruption, Radiology, Vol: 291, Pages: 459-466, ISSN: 0033-8419

Background Previous work has demonstrated that drugs can be delivered across the blood-brain barrier by exposing circulating microbubbles to a sequence of long ultrasound pulses. Although this sequence has successfully delivered drugs to the brain, concerns remain regarding potentially harmful effects from disrupting the brain vasculature. Purpose To determine whether a low-energy, rapid, short-pulse ultrasound sequence can efficiently and safely deliver drugs to the murine brain. Materials and Methods Twenty-eight female wild-type mice underwent focused ultrasound treatment after injections of microbubbles and a labeled model drug, while three control mice were not treated (May-November 2017). The left hippocampus of 14 mice was exposed to low-energy short pulses (1 MHz; five cycles; peak negative pressure, 0.35 MPa) of ultrasound emitted at a rapid rate (1.25 kHz) in bursts (0.5 Hz), and another 14 mice were exposed to standard long pulses (10 msec, 0.5 Hz) containing 150 times more acoustic energy. Mice were humanely killed at 0 (n = 5), 10 (n = 3), or 20 minutes (n = 3) after ultrasound treatment. Hematoxylin-eosin (H-E) staining was performed on three mice. The delivered drug dose and distribution were quantified with the normalized optical density and coefficient of variation. Safety was assessed by H-E staining, the amount of albumin released, and the duration of permeability change in the blood-brain barrier. Statistical analysis was performed by using the Student t test. Results The rapid short-pulse sequence delivered drugs uniformly throughout the parenchyma. The acoustic energy emitted from the microbubbles also predicted the delivered dose (r = 0.97). Disruption in the blood-brain barrier lasted less than 10 minutes and 3.4-fold less albumin was released into the brain than with long pulses. No vascular or tissue damage from rapid short-pulse exposure was observable using H-E staining. Conclusion The rapid short-pulse ultrasound sequence is a minimally

Journal article

Cooper S, Yue T, Miller P, Ma M, Long Net al., 2019, Tripodal N-centred phosphine ligands: Towards a novel donor set for Tc-99m and Re-186/188 radiopharmaceutical formulation, Publisher: WILEY, Pages: S295-S296, ISSN: 0362-4803

Conference paper

Pensa E, Karpowicz R, Jabaoński A, Trzybiński D, Woźniak K, Šakić D, Vrček V, Long NJ, Albrecht T, Kowalski Ket al., 2019, Gold-Induced Desulfurization in a Bis(ferrocenyl) Alkane Dithiol, Organometallics, ISSN: 0276-7333

© 2019 American Chemical Society. Thiol-modified ferrocenes on gold have been archetypical model systems for many fundamental charge transfer and other studies, since both thiol-gold and ferrocene redox chemistry are considered to be well-understood. Thus unexpectedly, we found that for a representative of a new class of flexibly linked bis-ferrocenyl compounds, namely, 1-10-bis(1-ferrocenyl)decane dithiol, surface immobilization on gold failed. Instead, in the presence of gold, molecular decomposition took place, resulting in sulfur-based adlayers and well-defined molecular elimination products, for which we provide spectroscopic evidence. Careful control experiments and comparison with related ferrocene compounds provide insight into the mechanism of the observed elimination reactions, as a combined effect of the molecular structure and the nature of the gold/sulfur bond. These findings, thus, have a broader impact on the design of molecular adlayers, for example, in the context of surface functionalization in sensing or the synthesis of gold nanoparticles.

Journal article

Clough TJ, Jiang L, Wong K-L, Long NJet al., 2019, Ligand design strategies to increase stability of gadolinium-based magnetic resonance imaging contrast agents, NATURE COMMUNICATIONS, Vol: 10, ISSN: 2041-1723

Journal article

Leow CH, Bush N, Stanziola A, Braga M, Shah A, Hernández-Gil J, Long NJ, Aboagye E, Bamber J, Tang Met al., 3D microvascular imaging using high frame rate ultrasound and ASAP without contrast agents: development and initial in vivo evaluation on non-tumour and tumour models, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN: 0885-3010

Three-dimensional imaging is valuable to non-invasively assess angiogenesis given the complex 3D architecture of vascular networks. The emergence of high frame rate (HFR) ultrasound, which can produce thousands of images per second, has inspired novel signal processing techniques and their applications in structural and functionalimaging of blood vessels. Although highly sensitive vascular mapping has been demonstrated using ultrafast Doppler, the detectability of microvasculature from the background noise may be hindered by the low signal to noise ratio (SNR) particularly in deeper region and without the use of contrast agents. We have recently demonstrated a coherence based technique, acoustic sub-aperture imaging (ASAP), for super-contrast vascular imaging and illustrated the contrast improvement using HFR contrast-enhanced ultrasound. In this work, we provide a feasibility study for microvascular imaging using ASAP without contrast agents, and extend its capability from 2D to volumetric vascular mapping. Using an ultrasound research system and a pre-clinical probe, we demonstrated the improved visibility of microvascular mapping using ASAP in comparison to ultrafast Power Doppler (PD) on a mouse kidney, liver and tumour without contrast agent injection. The SNR of ASAP images improves in average by 10dB when compared to PD. Besides, directional velocity mappings were also demonstrated by combining ASAP with the phase information extracted from lag-1 autocorrelation. Three-dimensional vascular and velocity mapping of the mouse kidney, liver and tumour were demonstrated by stackingthe ASAP images acquired using 2D ultrasound imaging and a trigger-controlled linear translation stage. The 3D results depicted clear micro-vasculature morphologies and function

Journal article

Hau Leow C, Bush NL, Stanziola A, Braga M, Shah A, Hemández-Gil J, Long NJ, Aboagye EO, Bamber JC, Tang MXet al., 2019, High-Contrast 3D in Vivo Microvascular Imaging Using Scanning 2D Ultrasound and Acoutic Sub-Aperture Processing (ASAP), IEEE International Ultrasonics Symposium, IUS. 2018, ISSN: 1948-5719

© 2018 IEEE. Non-invasive techniques for microvascular environment assessment are invaluable for clinical diagnosis and treatment monitoring. We recently developed a super contrast processing to suppress noise background in ultrafast Power Doppler, known an acoustic sub-aperture processing (ASAP), and demonstrate using 2D contrast enhance ultrasound. However, 2D imaging is insufficient to represent the 3D complex vascular environment. We therefore extend our study to demonstrate the feasibility of our technique for volumetric imaging. A pseudo-3D imaging technique was developed and demonstrated using a research system and preclinical transducer. A mouse liver was scanned using 2D ultrafast ultrasound and a mechanical translation stage. Initial results not only demonstrated a substantial noise reduction in 2D vascular images using ASAP, but also a high contrast volumetric rendering of a mouse liver. Our technique is ready for clinical use to provide better evaluation of angiogenesis.

Conference paper

Leow CH, Braga M, Bush NL, Stanziola A, Shah A, Hernández-Gil J, Long NJ, Aboagye EO, Bamber JC, Tang MXet al., 2019, Contrast vs Non-Contrast Enhanced Microvascular Imaging Using Acoustic Sub-Aperture Processing (ASAP): In Vivo Demonstration, IEEE International Ultrasonics Symposium, IUS. 2018, ISSN: 1948-5719

© 2018 IEEE. Angiogenesis plays a vital role in the progression of cancer. Non-invasive imaging techniques capable of assessing the microenvironment are therefore of clinical interest. Although highly sensitive vascular mapping has been demonstrated using ultrafast Power Doppler (PD), the detectability of microvasculature from the background noise may be hindered by the low signal-to-noise ratio (SNR) in deeper region and without the use of contrast agents. We recently developed acoustic sub-aperture processing (ASAP) processing for super-contrast vasculature imaging. This technique relies on the spatial coherence of the backscattered echoes over different acquisitions to substantially reduce the noise floor compared to the power Doppler (PD) technique. In this study, we demonstrate the feasibility of applying ASAP processing for non-contrast enhanced microvascular imaging in preclinical condition, and compare it with contrast enhanced ASAP as well as ultrafast PD. Comparing to PD, ASAP exhibit SNR improvement up to 12 dB. Higher SNR and extra visibility of smaller vessel are also demonstrated in contrast enhanced images in comparison to the non-contrast images. In conclusion, we have demonstrated the feasibility of using ASAP in vivo for non-contrast microvascular imaging, and the added benefit of using contrast agents in microvascular imaging.

Conference paper

Jantan KA, McArdle J, Mognon L, Fiorini V, Wilkinson LA, White AJP, Stagni S, Long NJ, Wilton-Ely Jet al., 2019, Heteromultimetallic compounds based on polyfunctional carboxylate linkers, New Journal of Chemistry, Vol: 43, Pages: 3199-3207, ISSN: 1144-0546

A series of homo- and hetero-nuclear, bi- and trimetallic compounds are accessible using polyfunctional linkers with carboxylic acid and alkynyl or pyridyl donor combinations. This versatile approach affords reaction at a specific donor site in each case, to accommodate both ruthenium(II) or osmium(II) units and also rhenium and gold centres. Due to the orientation of the nitrogen donors of the bipyridyl moiety in 2,2′-bipyridine-4,4′-dicarboxylic acid, the metal addition must be performed in a certain sequence due to steric considerations. One example was investigated crystallographically to add to the spectroscopic and analytical characterisation performed for all complexes. Photophysical investigations reveal the effect of incorporating second or third row transition metal centres. This approach was expanded through the use of a linker bearing both carboxylic acid and alkynyl functionalities, 1,1′-ethynylferrocene carboxylic acid. This allows initial coordination of the carboxylate donors to be followed by the formation of either an acetylide or a vinyl bridge to another metal, providing access to heterotrimetallic (FeRuOs and FeRuAu) compounds as well as a heteroheptametallic Fe3Ru2Au2 example. Preliminary electrochemical studies were performed on the latter compound.

Journal article

Rains JGD, ODonnelly K, Oliver T, Woscholski R, Long NJ, Barter LMCet al., 2019, Bicarbonate inhibition of carbonic anhydrase mimics hinders catalytic efficiency: Elucidating the mechanism and gaining insight toward improving speed and efficiency, ACS Catalysis, Vol: 9, Pages: 1353-1365, ISSN: 2155-5435

Carbonic anhydrase (CA) mimics are often studied with a focus on the hydration of CO2 for atmospheric carbon capture. Consequently, the reverse reaction (dehydration of HCO3–) has received minimal attention, so much so that the rate-limiting step of the dehydration reaction in CA mimics is currently unknown. The rate-limiting step of the hydration reaction is reported to be the bicarbonate-bound intermediate step, and thus is susceptible to product inhibition. It is not, however, clear if this inhibition is a consequence of an increase in the rate of the competing dehydration reaction or resulting from the strong affinity of bicarbonate to the mimic. To address this, insight into the dehydration reaction kinetics is needed. We therefore report the most comprehensive study of a CA mimic to date. The dehydration profile of the fastest small-molecule CA mimic, ZnL1S, was characterized, and consequently evidence for the rate-limiting step for the dehydration reaction was seen to be the bicarbonate-bound intermediate step, much like the hydration reaction. This experimental validation of the rate-limiting step was achieved through a variety of methods including NMR experiments and the effect of inhibitors, substrate concentration, and metal center on activity. With this understanding, an improvement in the favorability of the rate-limiting step was achieved, resulting in decreased bicarbonate inhibition. Thus, an increase in the mimic’s kcat for both reactions was observed, resulting in the largest rate constants of any small-molecule CA mimic reported to date (28 093 and 579 M–1 s–1 for hydration and dehydration, respectively). Enzyme-like kcat/km values were obtained for ZnL1S (5.9 × 105 M–1 s–1 for CO2 hydration), and notably there is only a difference of 2.5 orders of magnitude from the enzyme, the closest of any CA mimic reported in the literature. The results from this work can be applied to the development and improvement

Journal article

Zhang G, Lin S, Leow CH, Pang KT, Hernandez Gil J, Long N, Eckersley R, Tang M, Matsunaga Tet al., Quantification of vaporized targeted nanodroplets using high frame rate ultrasound and optics, Ultrasound in Medicine and Biology, ISSN: 0301-5629

Owing to their ability to efficiently deliver biological cargo and sense the intracellular milieu, vertical arrays of high aspect ratio nanostructures, known as nanoneedles,are being developed as minimally invasive tools for cell manipulation. However, little is known of the mechanisms of cargo transfer across the cell membrane-nanoneedle interface. Particularly,the contributions of membrane piercing, modulation of membrane permeability and endocytosis to cargo transfer remain largelyunexplored. Here, combining state-of-the-art electron and scanning ion conductance microscopy with molecular biology techniques, we show that porous silicon nanoneedle arrays concurrently stimulate independent endocytic pathways which contribute to enhanced biomolecule delivery into human mesenchymal stem cells. Electron microscopy of the cell membrane at nanoneedle sites shows an intact lipid bilayer, accompanied by an accumulation of clathrin-coated pits and caveolae. Nanoneedles enhance the internalisation of biomolecular markers of endocytosis, highlighting the concurrent activation of caveolae-and clathrin-mediated endocytosis, alongside macropinocytosis. These events contribute to the nanoneedle-mediated delivery (nanoinjection) of nucleic acids into human stem cells, which distribute across the cytosol and the endolysosomal system. This data extends the understanding of how nanoneedles modulate biological processes to mediate interaction with the intracellular space, providing indications for the rational design of improved cell-manipulation technologies.

Journal article

Wilkinson L, Massey E, Yue T, White A, Long Net al., 2019, Cyanoferrocenes as redox-active metalloligands for coordination-driven self-assembly, Dalton Transactions, Vol: 48, Pages: 72-78, ISSN: 1477-9234

Ferrocene-based Lewis bases have found utility as metalloligands in a wide variety of applications. The coordination chemistry of cyanoferrocenes however, is underexplored. Herein, we describe a new synthetic protocol for the generation of cyanoferrocenes. The coordination chemistry of these metalloligands to [Cu(NCMe)4][PF6], [(PPh3)2Cu(NCMe)2][PF6] and [(dppf)Cu(NCMe)2][PF6] salts has been explored, providing crystallographic evidence of cluster and polymeric forms of 1,1′- and 1,2-dicyanoferrocene complexes. The stability of the complexes and ligand dissociation were found to be strongly solvent-dependent.

Journal article

Smith A, Blower P, Southworth R, Ma M, Long Net al., 2018, Synthesis, gallium-68 radiolabelling and biological evaluation of a series of triarylphosphonium-functionalized DO3A chelators, Dalton Transactions, Vol: 47, Pages: 15448-15457, ISSN: 1477-9234

Radiolabelled lipophilic cations that accumulate in mitochondria according to the magnitude of the mitochondrial membrane potential can be used to report non-invasively on mitochondrial dysfunction in cardiovascular disease, cardiotoxicity, and cancer. While several such cations are already commercially available for SPECT imaging, PET offers greater promise in terms of sensitivity, resolution, and capacity for dynamic imaging and pharmacokinetic modelling. We have therefore synthesised a series of three triarylphosphonium-functionalised DO3A chelators for positron emitter gallium-68, with differing alkyl-functionalisation motifs to provide opportunities for tunable lipophilicity as a means of optimising their pharmacokinetics. To assess their capacity to report on mitochondrial membrane potential, we assessed their pharmacokinetic profiles in isolated tumour cells and isolated perfused rat hearts before and after mitochondrial depolarisation with the ionophore CCCP. All three compounds radiolabelled with over 97% RCY and exhibited log D values of between −3.12 and −1.81. In vitro assessment of the uptake of the radiotracers in cultured tumour cells showed a three-fold increase in uptake compared to unchelated [68Ga]Ga(III). However, each complex exhibited less than 1% retention in healthy hearts, which was not significantly diminished by mitochondrial depolarisation with CCCP. This preliminary work suggests that while this approach is promising, the lipophilicity of this class of tracers must be increased in order for them to be useful as cardiac or cancer imaging agents.

Journal article

Li B, Famili M, Pensa E, Grace I, Long NJ, Lambert C, Albrecht T, Cohen LFet al., 2018, Cross-plane conductance through a graphene/molecular monolayer/Au sandwich, Nanoscale, Vol: 10, Pages: 19791-19798, ISSN: 2040-3364

The functionalities offered by single-molecule electrical junctions are yet to be translated into monolayer or few-layer molecular films, where making effective and reproducible electrical contact is one of the challenging bottlenecks. Here we take a significant step in this direction by demonstrating that excellent electrical contact can be made with a monolayer biphenyl-4,4′-dithiol (BPDT) molecular film, sandwiched between gold and graphene electrodes. This sandwich device structure is advantageous, because the current flows through the molecules to the gold substrate in a ‘cross-plane’ manner, perpendicular to the plane of graphene, yielding high-conductance devices. We elucidate the nature of the cross-plane graphene/molecule/Au transport using quantum transport calculations and introduce a simple analytical model, which captures generic features of the current–voltage characteristic. Asymmetry in junction properties results from the disparity in electrode electrical properties, the alignment of the BPDT HOMO–LUMO energy levels and the specific characteristics of the graphene electrode. The experimental observation of scalability of junction properties within the junction area, in combination with a theoretical description of the transmission probability of the thiol–graphene contact, demonstrates that between 10% and 100% of the molecules make contact with the electrodes, which is several orders of magnitude greater than that achieved to date in the literature.

Journal article

Wilson LE, Jian X, White AJP, Long NJet al., 2018, Synthesis and characterisation of linear and towards cyclic diferrocenes with alkynyl spacers, Inorganics, Vol: 6, ISSN: 2304-6740

Ferrocenediyl systems offer a motif that incorporates multiple functionality and redox-active centers, enabling these units to be used as molecular scaffolds in linear and cyclic compounds. Herein, we discuss a new modular methodology for the synthesis and incorporation of ferrocenediyl motifs within extended conjugated systems. We have synthesized a family of compounds featuring ferrocenediyl-ethynyl units with various para-substituted aromatic linkages. Extended linear, open-chain species have been isolated and understanding towards the analogous cyclic compounds gained. The new compounds have been probed using NMR, mass spectrometry, cyclic voltammetry and X-ray crystallography to gain further understanding of their structural and electronic properties.

Journal article

Apps SL, White AJP, Miller PW, Long NJet al., 2018, Synthesis and reactivity of an N-triphos Mo(0) dinitrogen complex, Dalton Transactions, Vol: 47, Pages: 11386-11396, ISSN: 1477-9234

The preparation and reactivity of a novel molybdenum dinitrogen complex supported by a nitrogen-centred tripodal phosphine ligand (N-triphos, N(CH2PPh2)3, NP3Ph) are reported. Reaction of N-triphos with [MoX3(THF)3] (X = Cl, Br, I) gave the Mo(III) complex [MoX3(κ2-NP3Ph)(THF)] (1), where bidentate N-triphos coordination was observed. Reduction of this complex in the presence of dppm (bis(diphenylphosphino)methane) gave the dinitrogen complex [Mo(N2)(dppm)(κ3-NP3Ph)] (2), which exhibits moderate dinitrogen activation. An additional hydride complex, [Mo(H)2(dppm)(κ3-NP3Ph)] (4), was produced either as a minor side product during the reduction step, or as a major product by direct hydrogenation of the dinitrogen complex 2. The reactivity of the dinitrogen complex 2 with a range of Lewis acids was also investigated. At low temperatures, protic or borane Lewis acids (H+, BBr3 and tris(pentafluorophenyl)borane (BCF)) were found to coordinate to the apical nitrogen atom of the N-triphos ligand, with no conclusive evidence of any functionalisation of the dinitrogen ligand. Alkali metal Lewis acid addition to 2 resulted in the unexpected rearrangement of the N-triphos ligand to form [Mo(dppm)(PMePh2)(PCP)][B(C6F5)4] (7), where PCP, [Ph2PCNHCH2PPh2] is the carbenic ligand formed upon rearrangement from the reaction of 2 with M[B(C6F5)4] (M = Li, Na or K). Single crystal X-ray diffraction of complexes 1, 2, 4 and 7 provided structural confirmation of the N-triphos molybdenum complexes described.

Journal article

Evans RJ, Hernandez-Gil J, Mohri Z, Chooi KY, Lavin-Plaza B, Phinikaridou A, Pease JE, Krams R, Botnar R, Long NJet al., 2018, DEVELOPING NEW TARGETED MOLECULAR CONTRAST AGENTS FOR IMAGING INFLAMMATION OF VULNERABLE PLAQUES, Annual Meeting of the British-Atherosclerosis-Society (BAS), Publisher: OXFORD UNIV PRESS, Pages: S3-S4, ISSN: 0008-6363

Conference paper

Gawne P, Man F, Fonslet J, Radia R, Bordoloi J, Cleveland M, Jimenez-Royo P, Gabizon A, Blower PJ, Long N, de Rosales RTMet al., 2018, Manganese-52: applications in cell radiolabelling and liposomal nanomedicine PET imaging using oxine (8-hydroxyquinoline) as an ionophore, DALTON TRANSACTIONS, Vol: 47, Pages: 9283-9293, ISSN: 1477-9226

Journal article

Wang L, Long NJ, Li L, Lu Y, Li M, Cao J, Zhang Y, Zhang Q, Xu S, Yang Z, Mao C, Peng Met al., 2018, Multi-functional bismuth-doped bioglasses: combining bioactivity and photothermal response for bone tumor treatment and tissue repair, LIGHT-SCIENCE & APPLICATIONS, Vol: 7, ISSN: 2047-7538

Journal article

Zeng F, Wu Y, Li X, Ge X, Guo Q, Lou X, Cao Z, Hu B, Long NJ, Mao Y, Li Cet al., 2018, Custom-made ceria nanoparticles show a neuroprotective effect by modulating phenotypic polarization of the microglia, Angewandte Chemie International Edition, Vol: 57, Pages: 5808-5812, ISSN: 1521-3757

The neuroprotective effect of ceria nanoparticles in the context of brain disorders has been explained by their antioxidant effect. However, the in-depth mechanism remains unknown. As resident immune cells in the brain, microglia exert a variety of functional reprogramming termed as polarization in response to stress stimuli. Herein, custom-made ceria nanoparticles were developed and found to scavenge multiple reactive oxygen species with extremely high efficiency. These nanoparticles drove microglial polarization from a pro-inflammatory phenotype to an anti-inflammatory phenotype under pathological conditions. Pretreatment of these nanoparticles changed the microglial function from detrimental to protective for the neuronal cells by blocking the pro-inflammatory signaling. This work not only helps to elucidate the mechanism of ceria-nanoparticle-mediated neuroprotection but also provides a new strategy to rebalance the immuno-environment by switching the equilibrium of the phenotypic activation of microglia.

Journal article

Price TW, Firth G, Eling CJ, Kinnon M, Long NJ, Sturge J, Stasiuk GJet al., 2018, A F-18 radiolabelled Zn(II) sensing fluorescent probe, CHEMICAL COMMUNICATIONS, Vol: 54, Pages: 3227-3230, ISSN: 1359-7345

Journal article

Bamber J, Shah A, Bush N, Costa M, Harris-Birtill D, Lin S, Singh M, Scienti O, Darabara D, Elson D, ter Haar G, Rivens I, Long N, Tang Met al., Photoacoustic imaging and contrast agents in cancer research, Leeds Microbubble Symposium

Conference paper

Leow CH, Marta B, Stanziola A, Hernandez-Gil J, Long NJ, Aboagye EO, Tang M-Xet al., 2017, Multi-Frame Rate Plane Wave Contrast-Enhance Ultrasound Imaging for Tumour Vasculature Imaging and Perfusion Quantification, IEEE International Ultrasonics Symposium (IUS), Publisher: IEEE, ISSN: 1948-5719

A multi-frame rate plane wave imaging strategy is developed to simultaneously image tumor vasculature and quantify tumor perfusion. Customised imaging sequences interleaving a short but high frame rate (HFR) plane wave imaging sequence with a long but low frame rate imaging (LFR) sequence were implemented using a programmable ultrasound research platform. The results from a spatio-temporal coherence processing technique of ours demonstrated a significant improvement in the SNR and vasculature contrast when compared with the existing ultrafast Power Doppler (PD) using the same data. Initial perfusion quantification using LFR imaging was also demonstrated. Mean time intensity curve and some parametric measures were generated. Combining both structural and functional perfusion imaging using the multiframe rate sequences, a better evaluation of the tumour angiogenesis can be assessed.

Conference paper

Morse SV, Pouliopoulos AN, Chan T, Lin J, Copping M, Long NJ, Choi JJet al., 2017, Rapid short-pulse (RaSP) sequences improve the distribution of drug delivery to the brain in vivo, IEEE UFFC, Publisher: IEEE, ISSN: 1948-5719

Focused ultrasound and microbubbles have been shown to locally and noninvasively open the blood-brain barrier. Despite encouraging results in human patients, several performance and safety features, such as poor drug distribution, high drug accumulation along vessels and small sites of red blood cell extravasation, have been unavoidable. We have recently developed a new ultrasound sequence - rapid short-pulse (RaSP) sequence - designed to suppress these adverse features by promoting safer modes of cavitation activity throughout capillaries. In our RaSP sequences, low-pressure short ultrasonic pulses are emitted at kHz pulse repetition frequencies (PRF) and grouped into bursts. We have shown in vitro that RaSP sequences prolong microbubble lifetime and increase their mobility, enhancing the distribution of acoustic cavitation activity. Here we evaluate the ability of RaSP sequences to improve the in vivo performance and safety of ultrasound-mediated drug delivery to the brain.

Conference paper

Leow CH, Braga M, Hernandez-Gil J, Long NJ, Aboagye EO, Tang MXet al., 2017, Multi-frame rate plane wave contrast-enhanced ultrasound imaging for tumour vascular imaging and perfusion quantification, IEEE International Ultrasonics Symposium, IUS, Publisher: IEEE, ISSN: 1948-5719

Angiogenesis and blood flow dynamics play an important role in the development of malignant tumours and their response to treatment. While contrast enhanced ultrasound (CEUS) imaging with microbubble contrast agents as a tool for imaging angiogenesis and flow dynamics has shown great potential [1], recent development of plane wave high frame-rate (HFR) CEUS has offered new opportunities in such applications. In this study, we demonstrate an interleaved multi-frame rate plane wave CEUS imaging to quantify perfusion and to image vascular structure with improved resolution and contrast.

Conference paper

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00154586&limit=30&person=true