Microfluidics offers a way to generate consistent, monodisperse particles in a wide range of materials. Almost any type of particle can be produced by these methods: from liposomes to multiple emulsions; from hydrogels to polymers. However, these methods have generally been limited to low throughput, and been more suited to lab-scale development work. Dolomite Microfluidics is addressing this limitation by focusing on higher throughput techniques and highly parallel approaches.  We have developed new microfluidic methods and real time quality control tools, and we can now cover the range from a lab-scale development tool to ton-scale production-scale systems. This talk will explain our approach and give examples from a range of application areas.

A nucleic acid test (NAT) is a technique used to detect a particular nucleic acid, virus, or bacteria. In recent years, it has been applied to many applications such as clinical diagnoses, species identification, and food safety. However, in the conventional testing operation, the testing procedure for NAT is usually labor-intensive and time-consuming. It also required well-trained technician and the transfer of testing sample could result in nucleic acid contamination. Therefore, a user-friendly and automated assay process to conduct NAT is of great importance.

The major assay process for the NAT includes extraction, amplification, and detection. In the past few years, many microfluidic functions were developed for sample preparation and process automation. Kido et al. developed a cell-lysing approach by grinding the cell with beads. To control the movement of magnetic beads, Strohmeier et al. developed a Gas-phase transition magnetophoresis to transfer the magnetic beads through the liquid/air interface. To purify the nucleic acid, Berry et al. proposed an immiscible filtration assisted by surface tension technique.

In this work, an integrated and automated nucleic acid testing platform was developed using the centrifugal microfluidics. The microfluidic disk is able to lyse the cells, purified the nucleic acid through immiscible phases, and eluted the nucleic acid from the complex into the elution buffer. The eluted buffer can be used for amplification and quantification. A magnetic module was developed to transfer magnetic beads in the above-mentioned processes. This work provides an automated and user-friendly solution for the nucleic acid testing

This paper describes new and exciting applications for a  technology developed by Poly Pico ltd. We describe how this pico litre sample handling system is being developed for  time resolved pico litre protein crystallography investigations. The studies are planned for LCLS II at Stanford University and the European XFEL in Hamburg.

The standard Poly Poco system can deliver discreet droplets of fluid or in our case, fluid containing nano dimensional protein crystals at a rate up to 10KHz. The system currently being developed will deliver at a rate up to 50KHz and can be externally triggered so sample can be delivered when pulses of X rays are present and timed with the detector rate. Current sample delivery systems deliver a jet of protein crystals continuously and data collection is only a few percent from the total crystals supplied. Our new approach is even more important when using X-rays at the European XFEL as their X-rays are delivered with an unusual time structure. The beam has a repeating signature repeating  every 10HZ. It is off for 98% of the time  and then delivers up to 2700 pulses before going dark again. These discrete pulses are ideally positioned to study chemistry reactions in real time. For clarity, the pico system could use 16 of these tightly packed pulses, the only system in the world capable of doing so. The Poly Pico system  almost eliminates the sample wastage that is synonymous with continuous jetting. Other developments will also be described including temperature control for delivering viscous  material and alignment using electro-steering.

In vitro 3D tumor model has been sought to mimic critical in vivo pathological features that could be used for discovery of therapeutic treatment. Fabricating microwells based on existing lithography/cleanroom-based approaches are often costly and time-consuming that requires laborious process. Based on our previous work, this study presented a rapid and economical microwell fabrication methodology aimed to be conveniently incorporated with conventional workflow from biological and medical laboratories for generating in vitro 3D tumor spheroids. Ablation of CO₂ laser system was capable of easily incorporating z-axis adjustment to generate microwells with wide-rage size flexibilities, the side view of microwells revealed the depth and width fabricated under different laser power and focusing plane. Evaluation of tumor spheroid generated from different size of microwells was performed by CMFDA live cell staining, and hoechst nuclear staining indicated good cell viability and illustrated the shape of the tumor spheroids harvested from different size of microwells. To evaluate the preliminary therapeutic response on in vitro hepatocarcinoma tumor spheroid, photo-thermal treatment through bound ConA-Silicon Carbon Hollow Spheres (SCHS) was investigated, live/dead cell staining on tumor spheroid showed the photo-thermal effect could induce cancer cell death via exposure to NIR laser, resulting in higher red fluorescence under photo-thermal therapy. Preliminary therapeutic response from the hepatic 3D tumor spheroids with binding of ConA-SCHSs suggesting the current methodology combining this in vitro tumor model could serve as an effective tool for discovery of therapeutic motilities for cancer treatment.

The design and manufacturing of functional soft structures, based on multiple compartments delimited and interconnected by lipid-stabilised or surfactant-stabilised interfaces, are attracting an increasing level of attention. These soft constructs have shown a great potential as minimal cells in synthetic biology, simplified model systems for biophysical and biochemical studies and smart containers for drug delivery and microreactor technologies.

In recent years, microfluidic and optical methods for the manipulation of such soft interfaces have provided a substantial contribution to the design and development of novel artificial systems exhibiting interesting cell-like behaviours and functions. In this talk, I will present a number of optical and microfluidic techniques we developed for the construction and characterisation of artificial soft structures, including droplet interface bilayer architectures and soft nanotube networks. More specifically, I will discuss how accurate flow and particle handling operations within a microfluidic environment can be used to build artificial model systems from soft interfaces, such as lipid bilayer membranes and surfactant-stabilised oil-water interfaces. The resulting architectures can display biochemical and structural properties and functionalities, similar to those seen in living cell systems.

Synergistic combination of two or more drugs has been a major avenue targeting cancers. This regimen not only improves the therapeutic efficacy by triggering synthetic lethality in target cells but also minimizes the side effects by reducing drug doses. Therefore, the identification of optimal combination of various possible concentrations from a set of drugs presents a substantial challenge. Several approaches to optimize the selection regime have been demonstrated by various approaches; however, challenges still remain. For example, the time adopted for cell/drug preparation among the total independent screenings would last for days. In addition, the usage of standard multi-well plate assays would counter the feasibility for personalized medicine, which is inherently subject to a limited cell count from patient tumors. To address the technology gap described above, we herein present a bioinspired nanodroplet processing (BioNDP) platform for facilitating the high-throughput screening of optimal drug combinations. The platform was fabricated by a novel wax-imprinted laser direct writing, which is inspired from Stenocara gracilipes beetle’s bumpy back surfaces. Leveraging on advantages of utilizing customized liquid dispensing, cell counts and drugs adopted can be retained down to 50 cells and 200 nl for each test, respectively. We demonstrated an approximate 500-fold miniaturization of drug volumes does not impact both the in vitro and in vivo outcomes. In addition, such platform could present in vivo predictions more accurate than standard drug screening assays. Taken together, our results highlight the BioNDP platform could serve a cost-effective and high-throughput toolkit for improving pre-clinical drug screenings.

Micromixing is a crucial component of microfluidic systems which require mixing reagent molecules, fluids, or species for chemical reactions, which has applications in biomedical systems, chemical reactors, and polymerization . In this study, three curved serpentine micromixers consisting of ten segments with curvature angles of 180°, 230°, and 280° were fabricated to investigate the effects of curvature angle on inertial micromixing of two fluids. In this regard, water and diluted Rhodamine B solution were pumped into the micromixers over flow rates of 400-3000μL/min. To characterize and compare the mixing performance of the micromixers and to understand the underlying mechanisms, fluorescent intensity maps and mixing indeces were utilized. According to the results, up to the Reynolds number of 150, the mixing performance of the micromixers with curvature angles of 180° and 230° was similar to each other. While the micromixer having segments with 280° curvature angle showed higher mixing index values and thus outperformed the other two micromixers. This was due to severe distortion of flow streamlines by Dean vortices and occurrence of chaotic advection.

Double emulsions (DE) are complex fluid systems, with a core droplet (e.g. aqueous) surrounded by a liquid shell (e.g. of oil) and suspended in an external phase (e.g. aqueous).The thinner the shell is, the higher stability is shown by the DE. They found use in various fields of life sciences, from production of polymerosomes to screening rare cells via flow-cytometry.

Microfluidic production of emulsions is thoroughly investigated, both single and complex emulsions. Double emulsions, however, are mainly produced by active methods, i.e. by shearing off a core droplet (creating feed, single emulsion) and shearing off the feed emulsion into double emulsion. Passive methods, such as step emulsification, offer higher level of monodispersity of produced emulsions as well as greater ease of use and parallelization than active methods.