Originally the development of microfluidic MEMS devices was based entirely on silicon. The close coupling between electronics and fluid control would provide new platforms for advanced biomedical applications. It was assumed that large production volumes would reduce the cost of the silicon-based devices enough so that they could be used for single-use medical applications. Unfortunately, this has not happened and silicon MEMS are too expensive (~$0.05/mm2) to be disposable. As a result, we have refocused our Bio-MEMS research to use plastics made using 3-D printing and hot-embossing. The talk will describe how we can imbed microelectrodes in plastic devices. Early applications include cell cytometry, lysis, and electroporation. CMOS chips and graphene-based sensors can also be incorporated into the plastic microfluidic devices and connected to the electronic interconnects, thus making biomedical sensors with increased functionality possible. The second project involves a needle-free, microjet-based drug delivery system for oral delivery of protein drugs that we fabricate using 3-D printing. The ‘pill’ uses a solid-to-gas phase change to generate high internal pressure to create a liquid jet that can penetrate mucosal layers inside the cheek or in the intestine.

Fused silica glass is the material of choice whenever high chemical and thermal resilience combined with high optical transparency is needed. However structuring of fused silica is difficult and upscaling of microfluidic concepts in glass from laboratory scale prototypes to mass market manufacturing remains a problem. Here we present high-throughput thermal replication of fused silica glass using hot embossing, thermoforming and roll-to-roll replication. Therefore, thermoplastic nanocomposites are structured using classical polymer molding processes at moderate temperatures of 100 °C and pressures of 27 °MPa. The structured thermoplastic nanocomposites are then turned into fused silica glass in final heat treatment.

We demonstrate femtosecond laser direct writing (fs-LDW) of 3D proteinaceous microstructures of three different variants of serum albumin, which are human serum albumin (HSA), mouse serum albumin (MSA) and bovine serum albumin (BSA). Fs-LDW of proteinaceous 3D microstructures employs the direct exposure of a focused fs laser into aqueous solution containing protein molecules enabling fabrication of solid protein structure by cross-linking protein molecules along the exposure pathway. We examine the fabricated high-aspect-ratio structures by scanning electron microscopy and use finite element analysis to demonstrate material deformation.

In point of care diagnostics microfluidic paper-based analytical devices (µPADs) are promising to be a method that is cost efficient and simple and that they can be carried out without the need of high standard laboratories. Hydrophobic barriers are a key element for µPADs. However state of the art high resolution structuring methods mostly create barriers which easily break. Here we present a method which is able to generate hydrophobic barriers by a photoinduced silanization which are bendable, chemically resistant and autoclavable. Structuring of these barriers can be done via stereolithography printers or mask-based photolithography

Recently developed Laser Induced Deep Etching (LIDE) combines the advantage of high precision material manipulation by laser processing with high throughput characteristics of chemical etching. This opens the way for affordable mass production of glass microfluidics. LIDE is an unrivaled glass processing technology for microfluidics that allows the creation of various structural elements such as through holes, cutouts, grooves or breaking points without introducing any stress. Further directed functionalization by introducing chemical anchor groups for the binding of biomolecules or metallized areas for sensory functions in combination with glass welding techniques expand the fields of potential applications for LIDE considerably.

Polydimethyldisiloxane (PDMS) remains the polymer of choice for many microfluidic applications. Standard soft lithographic methods are based on channel molding and consecutive bonding of a lid. We have recently shown the production of smooth, circular three dimensional channels by zero-gravity printing of surfactant liquid threads into PDMS matrices, a technique we term “Suspended liquid subtractive Lithography SLSL”.We show the biocompatibility of the PDMS and developed novel matrices for SLSL such as room temperature curing systems like methacrylate gels to extend the applicability of the method to hydrophilic matrices.

Volumetric additive manufacturing can address many of the limitations that render other techniques, including fused deposition modeling, inkjetting, and projection stereolithography, challenging for the fabrication of microfluidic chips. Computed axial lithography (CAL) enables volumetric 3D-printing by illuminating a rotating container of photosensitive fluid with a 3D intensity map constructed from the angular superposition of many 2D projections. Since the uncured material provides mechanical support, the need for solid support structures is eliminated, chips remain intact during printing, and post-processing is greatly simplified. We report the use of CAL to fabricate transparent 3D fluidic networks in compliant hydrogels and stiffer polymers.

The raising importance of stereolithography (STL) printers for rapid prototyping of microfluidic chips is due to the combination of affordable machinery and high resolution. However most commercial printing materials have low chemical resistance to solvents and strong acids. Perfluoropolyethers (PFPE) are a class of materials which show a high chemical resistance. Here we present a new resin formulation which allows 3D printing of microfluidic structures with a channel size of 200 µm and a transparency of 90 % in the visible light region using PFPE methacrylates. We further show that using adapted PFPE resin formulations superhydrophobic surfaces can be printed.

Multiple materials are required to meet the needs of complex functionalities needed in biomedical applications, robotics and optoelectronics. The interface between materials is a source of failure and needs to be addressed. The solution needs to be able to incorporate both gradual and sharp transitions for a wide range of applications as demonstrated by examples in nature like mussels, squid beaks and osteochondral tissue. This work demonstrates the ability to control integration in 3D that ranges from 10s of microns to a couple millimeters.

We developed and advanced a next-generation method for chemical in situ biomolecule array synthesis. This allows for an unprecedented combinatorial freedom in the automated chemical synthesis of molecule arrays with very high spot densities. Key feature of this method is a laser transfer process: Tiny solid polymer material spots, incorporating different chemicals, are rapidly transferred from a donor film to an acceptor surface. In a separate heating step, the polymer becomes viscous and chemicals can diffuse within the polymer and couple to the acceptor surface. We employ such arrays for proteomics and infectious disease research (e.g. malaria, dengue fever).

Microfluidic technology enables the manipulation of liquids with nanoliter accuracy resulting in a wide variety of applications including rapid mixing and the ability to create free-standing liquid jets. This combination of properties has made microfluidics an attractive option for studying chemical dynamics at third-generation synchrotron and X-ray free electron laser sources (XFEL). The aim of this study is to develop an optimised microfluidic device for collecting chemically triggered molecular movie data at intense, femtosecond, XFEL sources. The results presented here will thus form a platform for developing future rapid mixing and jetting devices and help with the planning and execution of real-time molecular movie experiments.

A confocal Raman microscopy technique has been designed and demonstrated that measures the temperature rise and profile in microfluidic devices. The temperature rise in electrotrofluidic devices was studied showing that the temperature increase depended on the power used to move the sample along the channel (electroosmotic flow) and the particular design and structure of the device that determines the heat dissipation mechanism. No specific temperature sensitive particle needs to be added to the fluid, and has the additional virtue of allowing spatial scans in 3D.

Acoustophoresis devices are being proposed as tools for manipulation and diagnostic in microfluidic environments. We demonstrate that their wide use can be supported and enhanced by Digital Holography. Indeed, this technique covers all the current imaging needs and can stimulate the development of novel applications thanks to its unique features. We exploit the 3D tracking capabilities to measure tracer beads trajectories, which are then compared to theoretical models to calibrate the acoustic field. Furthermore, this technique provides quantitative phase maps, so it can be used to study the effect of ultrasounds on the position and morphology of cells.

Droplet based microfluidic platforms are attractive methods to move and manipulate discrete samples. The actuation of discrete droplets can be performed by generating electrostatic forces on an array of electrodes coated with an insulating dielectric i.e. electrowetting on dielectric, or alternatively through magnetic based actuation. Droplet-based systems rely on a hydrophobic (superhydrophobic) layer to minimize surface interaction/friction between the droplet and surface. As a result droplets can be made to slide across the surface with forces less than a microNewton. We examine the use of fluorinated (polymer silica nanoparticle based) coatings and slippery liquid infused porous surfaces (SLIPS) to manipulate droplets to carry out droplet actions such as dispensing, splitting, merging and mixing using gravity, magnetic actuation and Laplace pumping . Microfabricated and 3-D printed devices are utilized to carry out proof of principal assays with traditional detection (e.g. mass spectrometry and fluorescence) as well as cell phone based sensing through image analysis. Furthermore a laser micromachining approach is used to pattern “wettability” enabling the generation of droplet arrays and interconnected fluidic networks through discontinuous de-wetting.

We report a novel solution to allow multiplexed detection using a multi-path LFD fabricated via the precise partitioning of the single flow-path of a standard LFD using a laser direct-write technique. The multiple flow-paths allow individual detection of different analytes in each of the separated channels. We have successfully demonstrated the use of these multi-path LFDs for simultaneous detection of a biomarker panel comprising CRP and SAA-1, commonly used for the diagnosis of bacterial infections. In addition, clinical human samples have also been tested and the results show a high consistency with those acquired using the gold-standard ELISA test.

In this paper we describe the components of a portable point-of-analysis system prototype capable of simultaneously controlling the operation of integrated electrodes in the channels of a capillary-driven microfluidics device used to manipulate microbeads flowing with the fluid, and the detection and analysis of the fluorescent signal captured microbeads surface. A mobile device application manages the platform operation via Bluetooth and connects to a Cloud service for further data storage and analysis. We demonstrate the operation of the analysis device by measuring the fluorescent emission of functionalized 3µm microbeads trapped via dielectrophoresis above the integrated electrodes.

In previous work, a model has been developed to find the thermo-capillary force on a microbubble. When the microbubble is in the vicinity of a focused laser beam, it is attracted toward the focus due to the thermo-capillary force. Microbubbles are generated inside a thick cuvette through thermal blooming. The heat equation has been solved separately in the transverse and longitudinal directions to determine the corresponding components of the thermo-capillary forces. Here, the thermo-capillary force on a microbubble is determined by directly solving the 3D heat equation using COMSOL® and compared with numerical results obtained by 3D Fourier transform methods, as well as existing numerical results.

Circulating tumor cell (CTC) is found to be responsible for cancer metastases, and CTCs’ detection can serve as an important stage for cancer diagnosis. Deformation-based separation technique, which utilizes differences in deformability of the cells, has shown promising results in CTC detection and manipulation due to its simplicity, high performance and low cost. In the current work, we employed numerical simulations to study the pressure-deformability behavior of a single cell passing through a cylindrical microfilter. Our study provides an insight into the cell squeezing process and its characteristics, which can be used for designing the next-generation deformation-based CTC microfilters.

Most lab-on-a-chip systems still have to be considered as stationary, typically desktop-sized instruments. While the actual microfluidic cartridge often is comparatively compact, the associated instrument to operate this cartridge remains large. Two main aspects contribute to this situation: Detection systems remain relatively large and the fluidic control elements contribute to the system size and weight. We have tried to circumvent these problems by integrating both the detection system as well as all required liquid reagents into the disposable cartridge by using inkjet-printing of organic semiconductor materials and integrating reagents using blisters which can be easily actuated either manually or by a simple linear actuator.

Light irradiation is effective to control gel-sol transition spatially and the method enables cell arrangement by shaping gels. In this study, we propose a patterning method of DNA hydrogels by optical decomposition with visible-light. The property of DNA hydrogels can be changed by design of DNA sequences and modification of molecules. For photodecomposition of DNA hydrogels, an optical method for denaturing double-stranded DNA using a non-radiative relaxation process of excited quenchers is employed. The experiments demonstrated the decomposition of DNA hydrogels according to visible-light patterns and the control of the shape without changing the environment.

In this work we report fast and efficient synthesis of ZnO-NWs in situ within microfluidic chamber taking all the advantages of microfluidic devices. The growth done in dynamic mode involving flow of the growth solution inside the microchamber. Good quality and well-oriented ZnO-NWs are achieved having similar properties to the synthesized NWs in 2-3 hours growth time using the static method in just 8-16 minutes in dynamic mode. The quality of the NWs characterized using SEM and UV-Vis spectroscopy. This method opens the door for fast, cheap and localized growth of NWs to be used within microfluidics platforms

We report the use of a laser-based direct-writing technique to pattern paper-based microfluidic devices with unique fluid-filtration capabilities that enables separation of the various constituents of complex liquid sample input onto the device. For our first example we demonstrate the selective separation of differently sized Au-nanoparticles and latex microbeads from a water-based suspension using an in-line porous barrier laid across the fluid flow path. In another example we show the separation of plasma from red blood cells within whole blood using a partially-permeable flow-through filter created at the front end of the flow-channel.

Despite the recent advancement in 3D bioprinting technology, current commercial bioprinters are costly and restricted to limited axes of movement as well as design-specific extrusion methods. Hence, we developed a cost-effective robotic 3D bioprinting system compatible with peptide bioink, developed at KAUST’s Laboratory for Nanomedicine. The custom-designed system comprises of a bioprinting extruder, 3D-printed microfluidic pumps, a programmable robotic arm and a Graphical User Interface. Printed cellular 3D structures were found to be alive for three weeks. The success of the system highlights the potential of peptide bioink in facilitating human-like tissue and organ engineering for medical regenerative applications.

Chemotherapeutic drugs can penetrate healthy tissues by diffusion and convection. In a healthy tissue, the interstitial fluid is composed of an influx of nutrients and oxygen from blood vessels. In the case of cancerous tissue, the interstitial fluid is poorly drained due to the lack of lymphatic vasculature, resulting in an increase in interstitial pressure. Also, cancer cells invade a healthy tissue by pressing and pushing the surrounding environment, creating an increase in pressure inside the tumor and resulting in a large differential pressure between the tumor and the healthy tissue, resulting in an increase of extracellular matrix (ECM) stiffness. Therefore, due to high interstitial pressure in addition to matrix stiffening, penetration and distribution of systemic therapies are limited to diffusion, decreasing the efficacy of the cancer treatment. In the proposed work, different types of hydrogels were injected inside of a microfluidic device in order to mimic the extracellular matrix of a cancerous tissue. In addition to developing a microfluidic system that mimics a tumor microenvironment in vitro, this work systematically explored the transport of gold nanoparticles inside the microfluidic system, by tracking fluorescence. By tuning the hydrogel composition and concentration and by changing the surface charge of the gold nanoparticles, the impact in diffusion coefficient was evaluated.

A predominant challenge in tissue engineering is the need of a robust technique for producing structures with precise three-dimensional control of mechanical properties. This study focuses on the development of a model that allows for orthogonally programmable elastic modulus and geometry in a 3D hydrogel structure. We use pediatric physeal tissue engineering as a model application. A challenge related to physeal tissue regeneration is the presence of three distinct zones within the physis or growth plate, where cells evolve differently and are known to be sensitive to the mechanical environment. This work enables the fabrication of mechanically biomimetic tissue engineering microstructures.

In global healthcare and point-of-care diagnostics there is an increasing request of medical equipment with devices able to provide fast and reliable testing for clinical diagnosis. We show the recent advancements of Digital Holography microscopy applied to microfluidics to yield 3D imaging capabilities. Holographic flow cytometry through quantitative phase imaging and in-flow tomography for the analysis and manipulation of micro-particles and cells will be shown. Medical diagnostic applications based on DH will be also presented. Moreover, we introduce a portable common-path holographic microscope embedded onboard a microfluidic device that paves the way to the application of DH on the field

Platelets aggregations are critically involved in both normal hemostasis at the vascular injury. Here, we introduce an evaluation method of platelets aggregation when blood flows through a microchannel based on the measurement of laser speckle decorrelation time. In this study of speckle decorrelation time measurements by the blood flow in the microfluidic system, we monitored the presence or absence of platelets. This approach provides quick and quantitative evaluation of blood clotting. This finding provides a unique opportunity for fast and cost-effective detection of bleeding disorder prior to invasive surgery and quantitative monitoring anti-platelets therapies with only a drop of blood.

We developed a system for screening particles by means of optical scattering force in a micro fluidic channel. We created laminar flow of micro/nano particles aqueous suspension in the channel. Simultaneously, we launched laser light into the channel orthogonal to the flow. The particles experienced optical scattering force, hence, the particles deviated the flowing position from the original train. Depending on the optical cross-section, only the particles experiencing strong optical force were introduced to the one of the exit channels, however, the rest flew into another. We will show experimental results of screening particles by their size, shape, and color.

This work presents the development of a 3D printed micro-electro-fluidic probe (MeFP) for single cell electroporation. The MeFP builds on the concept of hydrodynamic flow confinement (HFC) -- that was originally introduced by the injection-aspiration configuration of the microfluidic probe (MFP) -- to eliminate the need for passing cells through closed microfluidic conduits during the process [2]. This novel tool builds on our developed framework for manufacturing MFPs using 3D printing [3]. The setup constitutes of an MeFP -- gold coated MFP with a single pin shaped micro-electrodes integrated on its tip -- and an ITO coated glass slide.

A novel method for sensitivity enhancement based on utilization of an optomechanical feedback loop is proposed for biosensing applications. One dimensional slot mode Photonic Crystal nanobeam cavity (PCNC) biosensor is designed and analyzed in terms of performance factors such as sensitivity and Q-factor. Inverse dependency of sensitivity and Q-factor on slot width is eliminated with the help of optomechanical positive feedback mechanism. Triggered by analyte introduction, feedback loop controls the optomechanical pump power through interference phenomenon, resulting in enhancement in the sensitivity of the device, without causing any degradation of the Q-factor.

In this work, a ring resonator is designed and analyzed for the spectral properties. A ring and a bus waveguide is designed with a core width of 0.2µm and cladding width of 2µm respectively. The structure is simulated with a wavelength of 1.55µm. An increase in the transmittance is observed by reducing the radius of the ring, various ring circumference is considered for the analysis. A small ring structure is taken for consideration, as the smaller ring will be useful in the bio-sensing application, which can further be fabricated for a point of care devices.

We present a novel sensor with unique surface modification technique to detect arsenic contamination of water by measuring the diffraction intensities induced by laser illumination. This approach involves usage of self-assembled patterns of glutathione on the gold-coated glass and an optical detection system. These self-assembled patterns are obtained through a micro-contact printing procedure. We demonstrate the potential use of Au-S and Au-O linkages to produce self-assembled thiol patterns that can be used for arsenic detection. Our findings recommend that this method can also be used for detection of a variety of other metallic and pathogenic contaminants like E.coli for water quality monitoring.

An optofluidic on-chip platform exploits a micro-jet waveguide for both Raman and fluorescence spectroscopy. Total internal reflection in a liquid waveguide with diameter of 150 µm efficiently collects Raman or fluorescence signal towards an optical fiber bundle connected to a mini-spectrometer. The chip (size 26 mm × 28 mm) allows horizontal ejection of the micro-jet waveguide and take advantage of a solution recirculation. The sensor versatility has been demonstrated by applying the platform in pharmaceutical analysis (riboflavin detection at 0.21 ng/ml level by means of fluorescence spectroscopy) and in Raman spectroscopy (ethanol limit of detection of 0.18% in water solutions).

We present the fabrication and characterization of optics integrated microfluidics, realized through a custom built resin-based additive manufacturing (or 3D priming) process. The resin chemistry is selected/altered to allow the fabrication of functionally graded sections of the parts by adding the resin, to the selected areas, with different properties than the rest of the layer. The process is repeated till the desired number of layers is achieved and the sections thus produced are used for focusing of light/laser beams inside the fluidic channels. We demonstrate application of the fabricated devices for visualization of nano/micro particles in the channels.

In the past years wearables have changed how we gather biometrics (e.g. activity, heart rate, sleep patterns). This is transforming expectations about what should be possible for health monitoring. To contribute, microfluidics must continue to provide on chip fluid handling, sensor miniaturization and robust material engineering. But also, and importantly, microfluidics must provide advances in existing technology to create seamless user experiences that will allow easy sample collection and preparation (i.e. sweat, saliva, blood, urine or tears). I will review a few historical examples and will provide a thinking framework for those interested in developing microfluidics for consumer electronics health applications.

We show a micro ring resonator (MRR) measurement platform that consists of a micro ring resonator chip, a liquid handling module and an optical signal read-out module. The MRR sensors were modified with thrombin binding aptamer and then used for detection of thrombin. The magnitude of the shift induced by the incubation with thrombin was concentration-dependent and revealed a dynamic range of roughly about 1-500 nM. Results from the thrombin binding experiment show a very stable performance during the course of multiple binding and regeneration cycles.

Fast liquid jets (<150 m/s) are used as a needle-free fluid injection into elastomeric tissue such as skin. Because the fluid droplets are smaller than a typical needle diameter, there is less collateral damage caused by the jets in the intervened body. We have implemented a laser-driven jetting system capable of generating supersonic liquid microjets. We have innovated the method to allow jetting in a repetitive regime with rates of up to 6 Hz, diameters of 10, 15 and 30 µm and velocities over 550 m/s. We investigate the potential of the method to deliver liquids into biological tissues with higher stiffness than a skin on hydrogel models (8-1000kPa).

In ovarian cancer patients, the ascitic currents, present in peritoneal cavity, play an important role in modulating the biology of the ovarian cancer as well as drug delivery. Permeability of tumor defines the flow dynamics over and through the tumor nodule. We propose to use experimental optical observations and mathematical descriptions of flow and mass transport for estimation of (i) the flow pattern around and through 3D porous cancer nodule surrogate, and (ii) the surrogate permeability. In this presentation, we show the feasibility of using particle image velocimetry (PIV) for estimating the permeability of a tumor surrogate by an optimization technique.

This invited talk will present an overview of my team's research in integrated photonics and automated, integrated microfluidics for various applications in biosensing. This will include our previous work in collaboration with Prof Laura Lechuga on automated sensing of antibiotics in sea water, more recent work in collaboration with Prof Hatice Altug on sustaining and monitoring the signalling of single cells and our most recent work on point of care diagnosis of cardio biomarkers for the rapid and conclusive assessment of heart attack.

A need exists for a portable instrument capable of in-field quantification of picoplankton in northern environments. To achieve this, we are developing a new cytometry technology using holographic spatial encoding which allows for multiplexed, single detector, intensity measurements of fluorescence from different photosynthetic pigments despite their overlapping fluorescence emission spectrums and that without the use of filtering is applied. In time, optofluidic integration of this technology will allow to reduce the instrument’s weight and size as well as eliminate the troublesome need for optical alignment providing a robust instrument for northern field research.

Droplet based microfluidic technology is a miniaturized platform for massive microbial analysis in picoliter scale. Scattered-light-based microbial detection provides a contact-free and label-free, yet sensitive measuring solution, since the angular-dependent scattered light delivers an elaborate interpretation of the appearance morphology and the physical properties of the microbial samples. In this paper, a novel approach of light scattering measurement in microfluidic chips is presented, engaging an optical fiber bundle for an angle-resolved, on-chip microbial detection. The optical fiber bundle has the advantage of combing both the sensitivity of angular-resolved light scattering measurement and the easy integration possibility of optical fibers.

Nowadays, high-speed video microscopy is used in many applications like microrheology [1,2] or flow cytometry [3] to measure mechanical properties of cells or to identify their type. Typically, high-speed cameras use buffering to reach very high frame rates due to the limited bandwidth of the interface to a PC like Ethernet. Additionally, analysis of large data is compute-intense and in many cases difficult to do online. We developed a system that consists of a high speed CMOS image sensor combined with a field programmable gate array (FPGA) and a pulsed LED illumination system. Due to an image transformation that is done on the FPGA, the dimensionality of the data is reduced without loss of important information. This leads to a significant reduction of the data as well as to noise reduction as a side effect. Furthermore, we developed a modular analysis toolkit that can be used to do the whole analysis directly on the same FPGA online so that buffering is not required and measurements can run continuously on high frame rates. Hence, we can analyze a large total number of objects at very high throughput rates in microfluidic devices. We present the analysis of diluted whole blood in a microfluidic system with our device as well as a sorting application that uses multiple regions of interest that are observed simultaneously so that particles can be analyzed before and after a manipulation or gate. [1] A. D. Wessel, M. Gumalla, J. Grosshans, Ch. F. Schmidt; Biophysical Journal, 108-8, 1899-1907; 2015. [2] I. Martin, M. Moch, T. Neckernuss, S. Paschke, H. Herrmann and O. Marti; Both monovalent cations and plectin are potent modulators of mechanical properties of keratin K8/K18 networks; Soft Matter, 12-33, 6964; 2016. [3] N. Toepfner et al.; Detection of human disease conditions by single-cell morpho-rheological phenotyping of blood; eLife, 7, e29213; 2018.

Caenorhabditis elegans nematodes are traditionally cultured on agar plates seeded with E. coli bacteria as food. Microfluidics promises precise spatio-temporal handling of biological reagents for more controlled manipulation and culture of worms and embryos. I will first discuss reversible worm immobilization protocols for high-resolution on-chip imaging. We have also realized worm bio-communication assays on-chip, microfluidic chips for automated embryo arraying, phenotyping, and long-term live imaging, as well as for drug studies performed during early embryogenesis. Microfluidic chips have allowed to study worm populations at individual animal resolution and to investigate individualized multi-phenotypic responses to drugs and genetic cues.

World Health Organization has identified antimicrobial resistance as one of the most serious global threat that require urgent actions. Therefore, we report on the fabrication of novel paper-based culture devices that allow prompt detection of bacterial pathogens and their antimicrobial resistance at the point-of-care. These unique devices were fabricated using a laser direct-write technique that relies on light-induced polymerization. Multiple well-like structures, laser-patterned in the paper-devices, and impregnated with agar (containing different antibiotics in various doses) allowed the selective growth/inhibition and thus detection/susceptibility-testing of E.coli/Pa (primary causes of urinary and upper respiratory tract infections) via a simple visually observable colour-change.

Recently, interest in the biophysics of cells has been stimulated by evidence from many studies that external force applied to a cell generates signals that are as potent as those of biochemical stimuli for cell growth, differentiation, migration and function. Furthermore, living cells as open systems maintain their homeostasis, i.e. the internal condition necessary for physiological functioning, by exchanging substances with their environments including energy substrate, ions and water across their membrane. Consequently, the objective of this project is to develop flow assays to study the biophysical properties of human cells with quantitative-phase digital holographic microscopy (QP-DHM).

Photoacoustic imaging has enabled researchers to study vascular profiles and dynamics in small animal tumor models in vivo. However, there is a need for cross-validation of the results and development of simulation platforms to accurately study the flow-dynamics in vitro. We have used low cost shrinky dinks (pre-stretched Polystyrene sheets) to fabricate microfluidic chips that mimic blood vessels, and used them to study flow profiles and blood- contrast agent mixing. Results were corroborated with in vivo small animal (kidney) perfusion imaging using hybrid photoacoustic/ultrasound imaging.

A novel centrifugal microfluidic platform for solid-phase-extraction (SPE) and fluorescence detection of oil in water is designed, fabricated, and tested. Mechanical pinch valves were used to manipulate flows of the sample and reagents. The valving system was simply controlled by the rotation frequency of the centrifugal platform. The prototype of the proposed system was 3D printed with PLA as the material. The test was conducted with 10ppm standard oil-water sample. Different stationary sorbent were used and compared. The experiment results showed that the fluorescence intensity of the sample was significantly increased. This platform can be potentially used as a portable on-situ enrichment and detection device for various of pollutant in environment water.