Imperial College London

DrGuidoBolognesi

Faculty of Natural SciencesDepartment of Chemistry

Visiting Researcher
 
 
 
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Contact

 

+44 (0)20 7594 1173g.bolognesi

 
 
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Location

 

542ChemistrySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

49 results found

Chen M, Farooqi ZH, Bolognesi G, Vladisavljević GTet al., 2023, Microfluidic Fabrication of Monodisperse and Recyclable TiO2-Poly(ethylene glycol) Diacrylate Hybrid Microgels for Removal of Methylene Blue from Aqueous Medium., Langmuir, Vol: 39, Pages: 18784-18796

Nearly monodisperse titanium oxide-polyethylene glycol diacrylate [TiO2-P(EGDA)] hybrid microbeads containing 0.5 wt % TiO2 nanoparticles entrapped within a P(EGDA) cross-linked polymeric network were synthesized using a modular Lego-inspired glass capillary microfluidic device. TiO2-P(EGDA) hybrid microgels were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and thermogravimetric analysis. The fabricated TiO2-P(EGDA) hybrid microgel system showed 100% removal efficiency of methylene blue (MB) from its 1-3 ppm aqueous solutions after 4 h of UV light irradiation at 0.2 mW/cm2 at the loading of 25 g/L photocatalyst beads in the reaction mixture, corresponding to the loading of naked TiO2 of just 0.025 g/L. No decrease in photocatalytic efficiency was observed in 10 repeated runs with recycled photocatalyst using a fresh 1 ppm MB solution in each cycle. The rate of photocatalytic degradation was controlled by the UV light irradiance, catalyst loading, and the initial dye concentration. Physical adsorption of MB onto the surface of composite microgel was also observed. The adsorption data was best fitted with the Langmuir adsorption isotherm and the Elovich kinetic model. TiO2-P(EGDA) microgel beads are biocompatible, can be prepared with a tunable size in the microfluidic device, and can easily be separated from the reaction mixture by gravity settling. The TiO2-P(EGDA) system can be used for the removal of other toxic dyes and micropollutants from industrial wastewater.

Journal article

Chen M, Kumrić KR, Thacker C, Prodanović R, Bolognesi G, Vladisavljević GTet al., 2023, Selective Adsorption of Ionic Species Using Macroporous Monodispersed Polyethylene Glycol Diacrylate/Acrylic Acid Microgels with Tunable Negative Charge., Gels, Vol: 9

Monodispersed polyethylene glycol diacrylate (PEGDA)/acrylic acid (AA) microgels with a tuneable negative charge and macroporous internal structure have been produced using a Lego-inspired droplet microfluidic device. The surface charge of microgels was controlled by changing the content of AA in the monomer mixture from zero (for noncharged PEGDA beads) to 4 wt%. The macroporosity of the polymer matrix was introduced by adding 20 wt% of 600-MW polyethylene glycol (PEG) as a porogen material into the monomer mixture. The porogen was successfully leached out with acetone after UV-crosslinking, which resulted in micron-sized cylindrical pores with crater-like morphology, uniformly arranged on the microgel surface. Negatively charged PEGDA/AA beads showed improved adsorption capacity towards positively charged organic dyes (methylene blue and rhodamine B) compared to neutral PEGDA beads and high repulsion of negatively charged dye molecules (methyl orange and congo red). Macroporous microgels showed better adsorption properties than nonporous beads, with a maximum adsorption capacity towards methylene blue of 45 mg/g for macroporous PEGDA/AA microgels at pH 8.6, as compared to 23 mg/g for nonporous PEGDA/AA microgels at the same pH. More than 98% of Cu(II) ions were removed from 50 ppm solution at pH 6.7 using 2.7 mg/mL of macroporous PEGDA/AA microgel. The adsorption of cationic species was significantly improved when pH was increased from 3 to 9 due to a higher degree of ionization of AA monomeric units in the polymer network. The synthesized copolymer beads can be used in drug delivery to achieve improved loading capacity of positively charged therapeutic agents and in tissue engineering, where a negative charge of scaffolds coupled with porous structure can help to achieve improved permeability of high-molecular-weight metabolites and nutrients, and anti-fouling activity against negatively charged species.

Journal article

Chakra A, Singh N, Vladisavljevic GT, Nadal F, Cottin-Bizonne C, Pirat C, Bolognesi Get al., 2023, Continuous Manipulation and Characterization of Colloidal Beads and Liposomes via Diffusiophoresis in Single- and Double-Junction Microchannels, ACS NANO, Vol: 17, Pages: 14644-14657, ISSN: 1936-0851

Journal article

Parvate S, Vladisavljevic GT, Leister N, Spyrou A, Bolognesi G, Baiocco D, Zhang Z, Chattopadhyay Set al., 2023, Lego-Inspired Glass Capillary Microfluidic Device: A Technique for Bespoke Microencapsulation of Phase Change Materials, ACS APPLIED MATERIALS & INTERFACES, Vol: 15, Pages: 17195-17210, ISSN: 1944-8244

Journal article

Singh N, Vladisavljevic GT, Nadal F, Cottin-Bizonne C, Pirat C, Bolognesi Get al., 2022, Enhanced Accumulation of Colloidal Particles in Microgrooved Channels via Diffusiophoresis and Steady-State Electrolyte Flows, LANGMUIR, Vol: 38, Pages: 14053-14062, ISSN: 0743-7463

Journal article

Singh N, Chakra A, Vladisavljevic GT, Cottin-Bizonne C, Pirat C, Bolognesi Get al., 2022, Composite Norland Optical Adhesive (NOA)/silicon flow focusing devices for colloidal particle manipulation and synthesis, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 652, ISSN: 0927-7757

Journal article

Zhang Z, Ekanem EE, Nakajima M, Bolognesi G, Vladisavljevic GTet al., 2022, Monodispersed Sirolimus-Loaded PLGA Microspheres with a Controlled Degree of Drug-Polymer Phase Separation for Drug-Coated Implantable Medical Devices and Subcutaneous Injection, ACS APPLIED BIO MATERIALS, Vol: 5, Pages: 3766-3777, ISSN: 2576-6422

Journal article

Chen M, Aluunmani R, Bolognesi G, Vladisavljevic GTet al., 2022, Facile Microfluidic Fabrication of Biocompatible Hydrogel Microspheres in a Novel Microfluidic Device, MOLECULES, Vol: 27

Journal article

Deydier T, Bolognesi G, Vladisavljevic GT, 2022, Scaled-up droplet generation in parallelised 3D flow focusing junctions, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 641, ISSN: 0927-7757

Journal article

Slavkovic-Beskoski L, Ignjatovic L, Bolognesi G, Maksin D, Savic A, Vladisavljevic G, Onjia Aet al., 2022, Dispersive Solid-Liquid Microextraction Based on the Poly(HDDA)/Graphene Sorbent Followed by ICP-MS for the Determination of Rare Earth Elements in Coal Fly Ash Leachate, METALS, Vol: 12

Journal article

Chen M, Bolognesi G, Vladisavljevic GT, 2021, Crosslinking Strategies for the Microfluidic Production of Microgels, MOLECULES, Vol: 26

Journal article

Chen M, Bolognesi G, Vladisavljević GT, 2021, Crosslinking Strategies for Microfluidic Production of Microgels

<jats:p>This article provides a systematic review of the crosslinking strategies used to produce microgel particles in microfluidic chips. Various ionic crosslinking methods for gelation of charged pol-ymers are discussed, including external gelation via crosslinkers dissolved or dispersed in the oil phase, internal gelation methods using crosslinkers added to the dispersed phase in their non-active forms, such as chelating agents, photo-acid generators, sparingly soluble or slowly hydrolyzing compounds, and methods involving competitive ligand exchange, rapid mixing of polymer and crosslinking streams, and merging polymer and crosslinker droplets. Covalent crosslinking methods using enzymatic oxidation of modified biopolymers, photo-polymerization of crosslinkable monomers or polymers, and thiol-ene “click” reactions are also discussed, as well as the methods based on sol-gel transitions of stimuli responsive polymers triggered by pH or temperature change. In addition to homogeneous microgel particles, the production of structurally heterogeneous particles such as composite hydrogel particles entrapping droplet interface bi-layers, core-shell particles, organoids, and Janus particles are also discussed. Microfluidics offers the ability to precisely tune chemical composition, size, shape, surface morphology, and internal structure of microgels by bringing in contact multiple fluid streams in a highly controlled fashion using versatile channel geometries and flow configurations and allowing controlled crosslinking.</jats:p>

Journal article

Zhang S, Contini C, Hindley J, Bolognesi G, Elani Y, Ces Oet al., 2021, Engineering motile aqueous phase-separated droplets via liposome stabilisation, Nature Communications, Vol: 12, Pages: 1-11, ISSN: 2041-1723

There are increasing efforts to engineer functional compartments that mimic cellular behaviours from the bottom-up. One behaviour that is receiving particular attention is motility, due to its biotechnological potential and ubiquity in living systems. Many existing platforms make use of the Marangoni effect to achieve motion in water/oil (w/o) droplet systems. However, most of these systems are unsuitable for biological applications due to biocompatibility issues caused by the presence of oil phases. Here we report a biocompatible all aqueous (w/w) PEG/dextran Pickering-like emulsion system consisting of liposome-stabilised cell-sized droplets, where the stability can be easily tuned by adjusting liposome composition and concentration. We demonstrate that the compartments are capable of negative chemotaxis: these droplets can respond to a PEG/dextran polymer gradient through directional motion down to the gradient. The biocompatibility, motility and partitioning abilities of this droplet system offers new directions to pursue research in motion-related biological processes.

Journal article

Singh N, Vladisavljevic GT, Nadal F, Cottin-Bizonne C, Pirat C, Bolognesi Get al., 2020, Reversible Trapping of Colloids in Microgrooved Channels via Diffusiophoresis under Steady-State Solute Gradients, PHYSICAL REVIEW LETTERS, Vol: 125, ISSN: 0031-9007

Journal article

Al Nuumani R, Smoukov SK, Bolognesi G, Vladisavljevic GTet al., 2020, Highly Porous Magnetic Janus Microparticles with Asymmetric Surface Topology, LANGMUIR, Vol: 36, Pages: 12702-12711, ISSN: 0743-7463

Journal article

Zhang S, Contini C, Hindley J, Bolognesi G, Elani Y, Ces Oet al., 2020, Engineering motile aqueous phase-separated droplets via liposome stabilisation

<jats:title>Abstract</jats:title> <jats:p>There are increasing efforts to engineer functional compartments that mimic aspects of cellular behaviour in a drive to construct an artificial cell from the bottom-up. One behaviour that is receiving particular attention is motility, due to its biotechnological potential and the fact that movement of discrete cells is a ubiquitous feature of living systems. Many existing platforms make use of the Marangoni effect to achieve motion in water/oil (w/o) droplet systems. However, most of these systems are unsuitable for biological applications due to issues with biocompatibility caused by the presence of oil phases. Here we report a biocompatible all aqueous (w/w) PEG/dextran Pickering-like emulsion system consisting of liposome-stabilized cell-sized droplets, where the stability can be easily tuned by adjusting liposome composition and concentration. We demonstrate that the compartments are capable of negative chemotaxis: if water is introduced into the emulsion system, these droplets can respond through directional motion away from PEG in the continuous phase and down to the polymer gradient with a velocity change proportional to the rearrangement of liposome stabilisers in the PEG/dextran interface. The biocompatibility, motility and partitioning abilities of this novel droplet system offers new directions to pursue research in motion-related biological processes.</jats:p>

Working paper

Vivek A, Bolognesi G, Elani Y, 2020, Fusing artificial cell compartments and lipid domains using optical traps: a tool to modulate membrane composition and phase behaviour, Micromachines, Vol: 11, ISSN: 2072-666X

New technologies for manipulating biomembranes have vast potential to aid the understanding of biological phenomena, and as tools to sculpt novel artificial cell architectures for synthetic biology. The manipulation and fusion of vesicles using optical traps is amongst the most promising due to the level of spatiotemporal control it affords. Herein, we conduct a suite of feasibility studies to show the potential of optical trapping technologies to (i) modulate the lipid composition of a vesicle by delivering new membrane material through fusion events and (ii) manipulate and controllably fuse coexisting membrane domains for the first time. We also outline some noteworthy morphologies and transitions that the vesicle undergoes during fusion, which gives us insight into the mechanisms at play. These results will guide future exploitation of laser-assisted membrane manipulation methods and feed into a technology roadmap for this emerging technology.

Journal article

Ogunyinka O, Wright A, Bolognesi G, Iza F, Bandulasena HCHet al., 2020, An integrated microfluidic chip for generation and transfer of reactive species using gas plasma, MICROFLUIDICS AND NANOFLUIDICS, Vol: 24, ISSN: 1613-4982

Journal article

Friddin M, Bolognesi G, Salehi-Reyhani A, Ces O, Elani Yet al., 2019, Direct manipulation of liquid ordered lipid membrane domains using optical traps, Communications Chemistry, Vol: 2, Pages: 1-7, ISSN: 2399-3669

Multicomponent lipid bilayers can give rise to coexisting liquid domains that are thought to influence a host of cellular activities. There currently exists no method to directly manipulate such domains, hampering our understanding of their significance. Here we report a system that allows individual liquid ordered domains that exist in a liquid disordered matrix to be directly manipulated using optical tweezers. This allows us to drag domains across the membrane surface of giant vesicles that are adhered to a glass surface, enabling domain location to be defined with spatiotemporal control. We can also use the laser to select individual vesicles in a population to undergo mixing/demixing by locally heating the membrane through the miscibility transition, demonstrating a further layer of control. This technology has potential as a tool to shed light on domain biophysics, on their role in biology, and in sculpting membrane assemblies with user-defined membrane patterning.

Journal article

Balzamo G, Singh N, Wang N, Vladisavljevic GT, Bolognesi G, Mele Eet al., 2019, 3D Arrays of Super-Hydrophobic Microtubes from Polypore Mushrooms as Naturally-Derived Systems for Oil Absorption, MATERIALS, Vol: 12

Journal article

Trantidou T, Friddin M, Gan KB, Han L, Bolognesi G, Brooks N, Ces Oet al., 2018, Mask-free laser lithography for rapid and low-cost microfluidic device fabrication, Analytical Chemistry, Vol: 90, Pages: 13915-13921, ISSN: 0003-2700

Microfluidics has become recognized as a powerful platform technology associated with a constantly increasing array of applications across the life sciences. This surge of interest over recent years has led to an increased demand for microfluidic chips, resulting in more time being spent in the cleanroom fabricating devices using soft lithography—a slow and expensive process that requires extensive materials, training and significant engineering resources. This bottleneck limits platform complexity as a byproduct of lengthy delays between device iterations and affects the time spent developing the final application. To address this problem, we report a new, rapid, and economical approach to microfluidic device fabrication using dry resist films to laminate laser cut sheets of acrylic. We term our method laser lithography and show that our technique can be used to engineer 200 μm width channels for assembling droplet generators capable of generating monodisperse water droplets in oil and micromixers designed to sustain chemical reactions. Our devices offer high transparency, negligible device to device variation, and low X-ray background scattering, demonstrating their suitability for real-time X-ray-based characterization applications. Our approach also requires minimal materials and apparatus, is cleanroom free, and at a cost of around $1.00 per chip could significantly democratize device fabrication, thereby increasing the interdisciplinary accessibility of microfluidics.

Journal article

Al Nuumani R, Bolognesi G, Vladisavljevic GT, 2018, Microfluidic Production of Poly(1,6-hexanediol diacrylate)-Based Polymer Microspheres and Bifunctional Microcapsules with Embedded TiO<sub>2</sub> Nanoparticles, LANGMUIR, Vol: 34, Pages: 11822-11831, ISSN: 0743-7463

Journal article

Bolognesi G, Friddin MS, Salehi-Reyhani S, Barlow N, Brooks NJ, Ces O, Elani Yet al., 2018, Sculpting and fusing biomimetic vesicle networks using optical tweezers, Nature Communications, Vol: 9, Pages: 1-11, ISSN: 2041-1723

Constructing higher-order vesicle assemblies has discipline-spanning potential from responsive soft-matter materials to artificial cell networks in synthetic biology. This potential is ultimately derived from the ability to compartmentalise and order chemical species in space. To unlock such applications, spatial organisation of vesicles in relation to one another must be controlled, and techniques to deliver cargo to compartments developed. Herein, we use optical tweezers to assemble, reconfigure and dismantle networks of cell-sized vesicles that, in different experimental scenarios, we engineer to exhibit several interesting properties. Vesicles are connected through double-bilayer junctions formed via electrostatically controlled adhesion. Chemically distinct vesicles are linked across length scales, from several nanometres to hundreds of micrometres, by axon-like tethers. In the former regime, patterning membranes with proteins and nanoparticles facilitates material exchange between compartments and enables laser-triggered vesicle merging. This allows us to mix and dilute content, and to initiate protein expression by delivering biomolecular reaction components.

Journal article

Karamdad K, Hindley J, Friddin MS, Bolognesi G, Law RV, Brooks NJ, Ces O, Elani Yet al., 2018, Engineering thermoresponsive phase separated vesicles formed via emulsion phase transfer as a content-release platform, Chemical Science, Vol: 9, Pages: 4851-4858, ISSN: 2041-6520

Giant unilamellar vesicles (GUVs) are a well-established tool for the study of membrane biophysics and are increasingly used as artificial cell models and functional units in biotechnology. This trend is driven by the development of emulsion-based generation methods such as Emulsion Phase Transfer (EPT), which facilitates the encapsulation of almost any water-soluble compounds (including biomolecules) regardless of size or charge, is compatible with droplet microfluidics, and allows GUVs with asymmetric bilayers to be assembled. However, the ability to control the composition of membranes formed via EPT remains an open question; this is key as composition gives rise to an array of biophysical phenomena which can be used to add functionality to membranes. Here, we evaluate the use of GUVs constructed via this method as a platform for phase behaviour studies and take advantage of composition-dependent features to engineer thermally-responsive GUVs. For the first time, we generate ternary GUVs (DOPC/DPPC/cholesterol) using EPT, and by compensating for the lower cholesterol incorporation efficiencies, show that these possess the full range of phase behaviour displayed by electroformed GUVs. As a demonstration of the fine control afforded by this approach, we demonstrate release of dye and peptide cargo when ternary GUVs are heated through the immiscibility transition temperature, and show that release temperature can be tuned by changing vesicle composition. We show that GUVs can be individually addressed and release triggered using a laser beam. Our findings validate EPT as a suitable method for generating phase separated vesicles and provide a valuable proof-of-concept for engineering content release functionality into individually addressable vesicles, which could have a host of applications in the development of smart synthetic biosystems.

Journal article

Barlow NE, Bolognesi G, Haylock S, Flemming AJ, Brooks NJ, Barter LMC, Ces Oet al., 2017, Rheological Droplet Interface Bilayers (rheo-DIBs): Probing the Unstirred Water Layer Effect on Membrane Permeability via Spinning Disk Induced Shear Stress, Scientific Reports, Vol: 7, ISSN: 2045-2322

A new rheological droplet interface bilayer (rheo-DIB) device is presented as a tool to apply shear stress on biological lipid membranes. Despite their exciting potential for affecting high-throughput membrane translocation studies, permeability assays conducted using DIBs have neglected the effect of the unstirred water layer (UWL). However as demonstrated in this study, neglecting this phenomenon can cause significant underestimates in membrane permeability measurements which in turn limits their ability to predict key processes such as drug translocation rates across lipid membranes. With the use of the rheo-DIB chip, the effective bilayer permeability can be modulated by applying shear stress to the droplet interfaces, inducing flow parallel to the DIB membranes. By analysing the relation between the effective membrane permeability and the applied stress, both the intrinsic membrane permeability and UWL thickness can be determined for the first time using this model membrane approach, thereby unlocking the potential of DIBs for undertaking diffusion assays. The results are also validated with numerical simulations.

Journal article

Barlow NE, Bolognesi G, Flemming AJ, Brooks N, Barter LMC, Ces Oet al., 2016, Multiplexed droplet Interface bilayer formation, Lab on a Chip, Vol: 16, Pages: 4653-4657, ISSN: 1473-0197

We present a simple method for the multiplexed formation ofdroplet interface bilayers (DIBs) using a mechanically operatedlinear acrylic chamber array. To demonstrate the functionality ofthe chip design, a lipid membrane permeability assay is performed.We show that multiple, symmetric DIBs can be created andseparated using this robust low-cost approach.

Journal article

Chan CL, Bolognesi G, Bhandarkar A, Friddin M, Brooks NJ, Seddon J, Law R, Barter L, Ceset al., 2016, DROPLAY: laser writing of functional patterns within biological microdroplet displays, Lab on a Chip, Vol: 16, Pages: 4621-4627, ISSN: 1473-0197

In this study, we introduce an optofluidic method for the rapid construction of large-area cell-sized droplet assemblieswith user-defined re-writable two-dimensional patterns of functional droplets. Light responsive water-in-oil dropletscapable of releasing fluorescent dye molecules upon exposure were generated and self-assembled into arrays in amicrofluidic device. This biological architecture was exploited by the scanning laser of a confocal microscope to ‘write’ userdefined patterns of differentiated (fluorescent) droplets in a network of originally undifferentiated (non-fluorescent)droplets. As a result, long lasting images were produced on a droplet fabric with droplets acting as pixels of a biologicalmonitor, which can be erased and re-written on-demand. Regio-specific light-induced droplet differentiation within a largepopulation of droplets provides a new paradigm for the rapid construction of bio-synthetic systems with potential as tissuemimics and biological display materials.

Journal article

Friddin MS, Bolognesi G, Elani Y, Brooks N, Law R, Seddon J, Neil M, ces Oet al., 2016, Optically assembled droplet interface bilayer (OptiDIB) networks from cell-sized microdroplets, Soft Matter, Vol: 12, Pages: 7731-7734, ISSN: 1744-6848

We report a new platform technology to systematically assemble droplet interface bilayer (DIB) networks in user-defined 3D architectures from cell-sized droplets using optical tweezers. Our OptiDIB platform is the first demonstration of optical trapping to precisely construct 3D DIB networks, paving the way for the development of a new generation of modular bio-systems.

Journal article

Friddin MS, Bolognesi G, Elani Y, Brooks N, Law R, Seddon J, Neil M, Ces Oet al., 2016, The optical assembly of bilayer networks from cell-sized droplets for synthetic biology, Systems and Synthetic Biology

Conference paper

Friddin MS, Bolognesi G, Elani Y, Brooks N, Law R, Seddon J, Neil M, Ces Oet al., 2016, Optical tweezers to assemble 2D and 3D droplet interface bilayer networks from cell-sized droplets, EMBL Microfluidics

Conference paper

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