Guido Bolognesi

Loughborough University | Lough · Department of Chemical Engineering

The delivery of colloidal particles in dead-end microstructures is very challenging, since these geometries do not allow net flows of particle-laden fluids; meanwhile, diffusive transport is slow and inefficient. Recently, we introduced a novel particle manipulation strategy, based on diffusiophoresis, whereby the salt concentration gradient betwee...

Monodispersed sirolimus (SRL)-loaded poly(lactic-co-glycolic acid) microspheres with a diameter of 1.8, 3.8, and 8.5 μm were produced by high-throughput microfluidic step emulsification─solvent evaporation using single crystal silicon chips consisted of 540-1710 terraced microchannels with a depth of 2, 4, or 5 μm arranged in 10 parallel arrays. Un...

Microfluidic flow focusing devices are widely used to generate steep chemical concentration gradients at the interface between miscible or partially miscible streams. In this study, first we present an optimised protocol for the manufacturing of composite flow focusing devices, consisting of a micropatterned layer of Norland Optical Adhesive (NOA)...

Poly(ethylene glycol) diacrylate (PEGDA) microgels with tuneable size and porosity find applications as extracellular matrix mimics for tissue-engineering scaffolds, biosensors, and drug carriers. Monodispersed PEGDA microgels were produced by modular droplet microfluidics using the dispersed phase with 49–99 wt% PEGDA, 1 wt% Darocur 2959, and 0–50...

Monodispersed organic phase droplets with an average diameter from 20 to 200 µm were produced at the rate of up to 20,000 droplets per second in a glass microfluidic chip composed of 7 parallel 3D flow focusing junctions with 100 μm-deep channels. The continuous phase was 2 wt% polyvinyl alcohol solution, while the dispersed phase was dichlorometha...

This article provides a systematic review of the crosslinking strategies used to produce microgel particles in microfluidic chips. Various ionic crosslinking methods for the gelation of charged polymers are discussed, including external gelation via crosslinkers dissolved or dispersed in the oil phase; internal gelation methods using crosslinkers a...

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 adde...

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) drop...

Supplementary video for the paper: "Highly porous magnetic Janus microparticles with asymmetric surface topology"

The controlled transport of colloids in dead-end structures is a key capability that can enable a wide range of applications, such as biochemical analysis, drug delivery, and underground oil recovery. This Letter presents a new trapping mechanism that allows the fast (i.e., within a few minutes) and reversible accumulation of submicron particles wi...

Monodispersed magnetic Janus particles composed of a porous polystyrene portion and a nonporous poly(vinyl acetate) portion with embedded oleic acid-coated magnetic nanoparticles were generated using microfluidic emulsification followed by two distinct phase separation events triggered by solvent evaporation. The template droplets were composed of...

The controlled transport of colloids in dead-end structures is a key capability that can enable a wide range of applications, such as bio-chemical analysis, drug delivery and underground oil recovery. This letter presents a new trapping mechanism that allows the fast (i.e., within a few minutes) and reversible accumulation of sub-micron particles w...

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 livin...

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...

Reactive species produced by atmospheric-pressure plasma (APP) are useful in many applications including disinfection, pretreatment, catalysis, detection and chemical synthesis. Most highly reactive species produced by plasma, such as ·OH, ¹O2 and \( {\text{O}}_{2}^{ \cdot - } \), are short-lived; therefore, in situ generation is essential to trans...

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 di...

Porous materials derived from natural resources, such as Luffa sponges, pomelo peel and jute fibres, have recently emerged as oil adsorbents for water purification, due to their suitability, low environmental impact, biodegradability and low cost. Here we show, for the first time, that the porosity of the fruiting body of polypore mushrooms can be...

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 -...

Application of TiO2 as a photocatalyst and UV protector is restricted by the difficulties in the recovery of TiO2 nanoparticles after water treatment. In this work, TiO2 nanoparticles (Degussa P25) were immobilised within easily recoverable poly(1,6-hexanediol diacrylate)-based polymer microspheres produced by on-the-fly photopolymerisation of micr...

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 relatio...

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 almos...

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 dem...

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

In this study, we introduce an optofluidic method for the rapid construction of large-area cell-sized droplet assemblies with user-defined, re-writable, two-dimensional patterns of functional droplets. Light responsive water-in-oil droplets capable of releasing fluorescent dye molecules upon exposure were generated and self-assembled into arrays in...

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 o...

Measurements of the ultralow interfacial tension and surfactant film bending rigidity for micron-sized heptane droplets in AOT-NaCl aqueous solutions were performed in a microfluidic device through the analysis of thermally-driven droplet interface fluctuations. The Fourier spectrum of the stochastic droplet interface displacement was measured thro...

This talk will outline novel microfluidic strategies for biomembrane engineering that are capable of fabricating vesicles [1], droplet interface bilayer networks [2], multisomes [3] and artificial tissues [4] where parameters such as membrane asymmetry, membrane curvature, compartment connectivity and individual compartment contents can be controll...

We present a microfluidic platform for the generation, characterization and optical manipulation of monodisperse oil droplets in water with equilibrium interfacial tensions on the order of 0.1-1μN/m. An oil-in-water emulsion containing the surfactant Aerosol OT, heptane, water and sodium chloride under conditions close to the microemulsion phase tr...

We present a novel microfluidic approach for the generation of monodisperse oil droplets in water with interfacial tensions of the order of 1µN/m. Using an oil-in-water emulsion containing the surfactant Aerosol OT, heptane, water and sodium chloride under conditions close to the microemulsion phase transition, we actively controlled the surface te...

The usual boundary condition for liquids at macroscale is the no-slip condition. In micro and nanofluidic systems often liquid slippage at solid wall is observed. Nanoscale rough hydrophobic surfaces induce large liquid slippage due to entrapment of air pockets in the surface asperities (super-hydrophobic Cassie state). In this contribution we disc...

We present a novel microfluidic approach for the generation of monodisperse oil droplets in water with ultra-low interfacial tensions. Using an oil-water-surfactant formulation under conditions close to the microemulsion phase transition, we actively controlled the surface tension at the liquid-liquid interface within the microfluidic device in ord...

A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air...

A full characterization of the water flow past a silicon superhydrophobic surface with longitudinal micro-grooves enclosed in a microfluidic device is presented. Fluorescence microscopy images of the flow seeded with fluorescent passive tracers were digitally processed to measure both the velocity field and the position and shape of the liquid-air...

Nanoscale roughness in combination with surface chemistry modification can achieve large liquid slippage due to entrapment of air pockets in the surface asperities (superhydrophobic Cassie state). However, pressure increase may result in the collapse of the gaseous enclaves into the fully wet Wenzel state, and in the irreversible loss of the desira...

Structured hydrophobic surfaces may present high wall slippage due to the microscopic details of wetting. This behavior can be exploited for reducing wall slippage in micro- and nanofluidic devices. In this work we focus on the influence of meniscus curvature and pressure on the slip length. We use realistic atomistic potentials in order to simulat...

We discuss the design, implementation and performance of a novel platform for the production and optical control of ultra-low interfacial tension droplets in the 1-10 micron regime. A custom-designed, integrated microfluidic system allows the production of oil-in-water emulsion droplets of controllable size. This provides an optimised physical plat...

We present a novel approach which allows simultaneous measurement of the velocity field and the interface profile close to a composite liquid–gas and solid–gas interface. The proposed scheme is the method of choice for the characterization of those flows where the velocity field is highly dependent on the actual shape and position assumed by liquid...

Microbubbles are often used as ultrasound contrast agents for sonography. However, polymer-shelled microbubbles have the potential to support also additional functionalities such as, for example, targeted drug delivery. Using digital holographic micros- copy we demonstrate that structural information on individual bubbles can be retrieved with high...

The development and the success of microfluidics in the last 15 years is mainly due to the concept of lab-on-a-chip. Those miniaturized devices, integrating one or more laboratory functions, have aroused great interest among several research areas as physics, chemistry, biology and bioengineering. The high hydrodynamic resistance the liquid experie...

Microfluidics is a very recent branch of science and technology. The development and the success, it has had in the last 15 years, is mainly due to the concept of lab-on-a-chip. Those miniaturized devices, integrating one or more laboratory functions, have aroused great interest among several research areas as physics, chemistry, biology and bioeng...

Microbubbles are often used as ultrasound contrast agents for sonography. However, polymer-shelled microbubbles have the potential to support also additional functionalities such as, for example, targeted drug delivery. Using digital holographic microscopy we demonstrate that structural information on individual bubbles can be retrieved with high p...

In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet attack to produce p...

Digital holographic microscopy provides an ideal tool for 3D tracking of microspheres while simultaneously allowing a full and accurate characterization of their main physical properties such as: radius and refractive index. We demonstrate that the combination of high resolution multipoint tracking and accurate optical sizing of tracers provides an...

Digital holographic microscopy is used to numerically refocus a recorded hologram at an arbitrary axial distance. However, as a straightforward property of coherent light fields, image reconstruction on an arbitrary tilted plane could be directly obtained by a rotation in k-space. We demonstrate that this property allows the real-time microscopic i...

Moving micron-scale objects are strongly coupled to each other by hydrodynamic interactions. The strength of this coupling decays with the inverse particle separation when the two objects are sufficiently far apart. It has been recently demonstrated that the reduced dimensionality of a thin fluid layer gives rise to longer-ranged, logarithmic coupl...

Moving micron scale objects are strongly coupled to each other by hydrodynamic interactions. The strength of this coupling decays as the inverse particle separation when the two objects are sufficiently far apart. It has been recently demonstrated that the reduced dimensionality of thin fluid layer gives rise to longer ranged, logarithmic coupling....

In this paper, we present an inexpensive technique to produce superhydrophobic surfaces from porous silicon. Superhydrophobic surfaces are a key technology for their ability to reduce friction losses in microchannels and their self cleaning properties. The morphology of a p-type silicon wafer is modified by a electrochemical wet etch to produce por...