Lab-on-a-chip for drug development

Integration of acoustic micromixing with cyclic olefin copolymer microfluidics for enhanced lab-on-a-chip applications in nanoscale liposome synthesis

The integration of acoustic wave micromixing with microfluidic systems holds great potential for applications in biomedicine and lab-on-a-chip technologies. Polymers such as cyclic olefin copolymer (COC) are increasingly utilized in microfluidic applications due to its unique properties, low cost, and versatile fabrication methods, and incorporating them into acoustofluidics significantly expands their potential applications. In this work, for the first time, we demonstrated the integration of polymer microfluidics with acoustic micromixing utilizing oscillating sharp edge structures to homogenize flowing fluids. The sharp edge mixing platform was entirely composed of COC fabricated in a COC-hydrocarbon solvent swelling based microfabrication process. As an electrical signal is applied to a piezoelectric transducer bonded to the micromixer, the sharp edges start to oscillate generating vortices at its tip, mixing the fluids. A 2D numerical model was implemented to determine the optimum microchannel dimensions for experimental mixing assessment. The system was shown to successfully mix fluids at flow rates up to 150µl h-1and has a modest effect even at the highest tested flow rate of 600µl h-1. The utility of the fabricated sharp edge micromixer was demonstrated by the synthesis of nanoscale liposomes.

Lab on chip for testing of repurposed drugs

The lab-on-chip technique broadly comprises of microfluidics and aims to progress multidimensionally by changing the outlook of medicine and pharmaceuticals as it finds it roots in miniaturization. Moreover, microfluidics facilitates precise physiological simulation and possesses biological system-mimicking capabilities for drug development and repurposing. Thus, organs on chip could pave a revolutionary pathway in the field of drug development and repurposing by reducing animal testing and improving drug repurposing.

Accelerating attribute-focused process and product development through the development and deployment of autonomous process analytical technology platform system

Enabling real-time monitoring and control of the biomanufacturing processes through product quality insights continues to be an area of focus in the biopharmaceutical industry. The goal is to manufacture products with the desired quality attributes. To realize this rigorous attribute-focused Quality by Design approach, it is critical to support the development of processes that consistently deliver high-quality products and facilitate product commercialization. Time delays associated with offline analytical testing can limit the speed of process development. Thus, developing and deploying analytical technology is necessary to accelerate process development. In this study, we have developed the micro sequential injection process analyzer and the automatic assay preparation platform system. These innovations address the unmet need for an automatic, online, real-time sample acquisition and preparation platform system for in-process monitoring, control, and release of biopharmaceuticals. These systems can also be deployed in laboratory areas as an offline analytical system and on the manufacturing floor to enable rapid testing and release of products manufactured in a good manufacturing practice environment.

Quercetin nanocrystals prepared using a microfluidic chip with improved in vitro dissolution

OBJECTIVE

In order to improve the dissolution property of quercetin (QCT), the quercetin nanocrystals (QNCs) were prepared in this study.

METHODS

QNCs were prepared by a 100 μm diameter Y-shape microfluidic channel. Some impact factors affecting the generation of QNCs such as concentration and flow rate were investigated. Furthermore, the fluid mixing in the microfluidic channel was simulated by fluid software.

RESULTS

XRPD and DSC analyses indicated that the prepared QNCs were amorphous. Stable QNCs with a particle size of 77.9 ± 3.63 nm and polydispersity index of 0.26 ± 0.02 were obtained. TEM showed that the as-prepared QNCs had a uniform spherical shape with an average particle size of about 100-300 nm. In the dissolution medium without cosolvent Tween -80, the dissolution of QCT was poor, its final accumulated dissolution was only 3.95%, while that of QNCs was 66%.

CONCLUSION

When QCT was changed to QNCs by microfluidic technology, its dissolution property could be obviously improved. Therefore, microfluidic technology as a new method to prepare nanocrystals has a good applying prospect in improving dissolution property for poorly water-soluble drugs.

Triboelectric Nanogenerators: Low-Cost Power Supplies for Improved Electrospray Ionization

Electrospray ionization (ESI) is one of the most popular methods to generate ions for mass spectrometry (MS). When compared with other ionization techniques, it can generate ions from liquid-phase samples without additives, retaining covalent and non-covalent interactions of the molecules of interest. When hyphenated to liquid chromatography, it greatly expands the versatility of MS analysis of complex mixtures. However, despite the extensive growth in the application of ESI, the technique still suffers from some drawbacks when powered by direct current (DC) power supplies. Triboelectric nanogenerators promise to be a new power source for the generation of ions by ESI, improving on the analytical capabilities of traditional DC ESI. In this review we highlight the fundamentals of ESI driven by DC power supplies, its contrasting qualities to triboelectric nanogenerator power supplies, and its applications to three distinct fields of research: forensics, metabolomics, and protein structure analysis.

Applications of Lab on a Chip in Antimicrobial Susceptibility of Staphylococcus aureus: A Systematic Review

Background and Objectives: Staphylococcus aureus is a prevalent bacterium capable of inducing various infections, including skin and soft tissue infections, bloodstream infections, pneumonia, and surgical site infections. The emergence of antimicrobial resistance in S. aureus, particularly methicillin-resistant S. aureus, has raised substantial concerns within global healthcare settings. Prior to antibiotic prescription, the ideal approach is antimicrobial susceptibility testing (AST); however, this is frequently perceived as excessively complex and time-intensive. Lab-on-a-chip (LOC) technology holds promise in addressing these challenges and advancing fundamental microbiological research while also aiding in the development of therapeutic strategies. This systematic review aims to evaluate the potential utility of LOC for AST of S. aureus. Materials and Methods: This study adhered to the PRISMA guidelines. Various databases, including SCOPUS, PubMed/MEDLINE, SCIELO, and LILACS, in addition to gray literature sources, were employed in the review process. Results: Sixteen studies were included in this systematic review. All these studies detailed the effectiveness, rapidity, and predictability of LOC systems for assessing S. aureus susceptibility to various antibiotics. When comparing the LOC approach to traditional manual methods, it was evident that LOC requires a minimal quantity of reagents. Furthermore, most studies reported that the entire LOC procedure took 10 min to 7 h, with results being equally accurate as those obtained through traditional AST protocols. Conclusions: The potential application of LOC for AST of S. aureus is emphasized by its ability to provide rapid access to minimum inhibitory concentration data, which can substantially aid in selecting the most suitable antibiotics and dosages for treating challenging infections caused by this microorganism. Moreover, the rapid AST facilitated by LOC holds promise for enhancing the appropriateness and efficacy of therapy in clinical settings.

Bio-Microfabrication of 2D and 3D Biomimetic Gut-on-a-Chip

Traditional goal of microfabrication was to limitedly construct nano- and micro-geometries on silicon or quartz wafers using various semiconductor manufacturing technologies, such as photolithography, soft lithography, etching, deposition, and so on. However, recent integration with biotechnologies has led to a wide expansion of microfabrication. In particular, many researchers studying pharmacology and pathology are very interested in producing in vitro models that mimic the actual intestine to study the effectiveness of new drug testing and interactions between organs. Various bio-microfabrication techniques have been developed while solving inherent problems when developing in vitro micromodels that mimic the real large intestine. This intensive review introduces various bio-microfabrication techniques that have been used, until recently, to realize two-dimensional and three-dimensional biomimetic experimental models. Regarding the topic of gut chips, two major review subtopics and two-dimensional and three-dimensional gut chips were employed, focusing on the membrane-based manufacturing process for two-dimensional gut chips and the scaffold-based manufacturing process for three-dimensional gut chips, respectively.

Prospection of Microfluidics for Local Drug Delivery

Significant endeavors can be made to develop effective drug delivery systems. Nowadays, many of these novel systems have gained attention as they focus primarily on increasing the bioavailability and bioaccessibility of several drugs to finally minimize the side effects, thus improving the treatment's efficacy. Microfluidics systems are unquestionably a superior technology, which is currently revolutionizing the current chemical and biological studies, providing diminutive chip-scale devices that offer precise dosage, target-precise delivery, and controlled release. Microfluidic systems have emerged as a promising delivery vehicle owing to their potential for defined handling and transporting of small liquid quantities. The latest microfabrication developments have been made for application to several biological systems. Here, we review the fundamentals of microfluidics and their application for local drug delivery.

Multi-objective optimization of split and recombine micromixer using grey relational analysis method

Purpose

The effective, efficient and optimal design of micromixer is the need in the field of biochemical and biomedical diagnostic systems.

Design/methodology/approach

In this paper, multi-objective optimization of split and recombine micromixer (SRM) with different geometrical configurations is carried out. The finite element method-based three-dimensional models are prepared and analyzed using COMSOL Multiphysics 5.0 Software. Taguchi’s design of experiment (DoE), main effect plot analysis, ANOVA and grey relational analysis (GRA) method are used to find out optimum condition. The five geometrical parameters with three levels, namely, angle between inlets, pillar size, pillar shape, aspect ratio and constriction height of SRM are considered as design variables. The mixing index (MXI) and pressure drop (∆P) are considered objective functions.

Findings

The MXI is significantly influenced by pillar shape and aspect ratio, whereas the pressure drop (∆P) by constriction height. Maximum MXI (0.97) with minimum pressure drop (64,587 Pa) is the optimal conditions and obtained at 180 deg angle between inlets, 50 µm of pillar size, 1.5 of aspect ratio, 100 µm of constriction height and ellipse shape pillar cross-section, respectively.

Research limitations/implications

This optimized SRM can be combined with lab-on-a-chip for biochemical and biomedical analysis.

Originality/value

This work is useful to obtain optimal geometry of SRM for getting efficient performance of micromixer.

Microfluidic chips: recent advances, critical strategies in design, applications and future perspectives

Microfluidic chip technology is an emerging tool in the field of biomedical application. Microfluidic chip includes a set of groves or microchannels that are engraved on different materials (glass, silicon, or polymers such as polydimethylsiloxane or PDMS, polymethylmethacrylate or PMMA). The microchannels forming the microfluidic chip are interconnected with each other for desired results. This organization of microchannels trapped into the microfluidic chip is associated with the outside by inputs and outputs penetrating through the chip, as an interface between the macro- and miniature world. With the help of a pump and a chip, microfluidic chip helps to determine the behavioral change of the microfluids. Inside the chip, there are microfluidic channels that permit the processing of the fluid, for example, blending and physicochemical responses. Microfluidic chip has numerous points of interest including lesser time and reagent utilization and alongside this, it can execute numerous activities simultaneously. The miniatured size of the chip fastens the reaction as the surface area increases. It is utilized in different biomedical applications such as food safety sensing, peptide analysis, tissue engineering, medical diagnosis, DNA purification, PCR activity, pregnancy, and glucose estimation. In the present study, the design of various microfluidic chips has been discussed along with their biomedical applications.

Evolution of Plant Virus Diagnostics Used in Australian Post Entry Quarantine

As part of a special edition for MDPI on plant virology in Australia, this review provides a brief high-level overview on the evolution of diagnostic techniques used in Australian government Post-Entry Quarantine (PEQ) facilities for testing imported plants for viruses. A comprehensive range of traditional and modern diagnostic approaches have historically been employed in PEQ facilities using bioassays, serological, and molecular techniques. Whilst these techniques have been effective, they are time consuming, resource intensive and expensive. The review highlights the importance of ensuring the best available science and diagnostic developments are constantly tested, evaluated, and implemented by regulators to ensure primary producers have rapid and safe access to new genetics to remain productive, sustainable and competitive.

Impact of Silanization Parameters and Antibody Immobilization Strategy on Binding Capacity of Photonic Ring Resonators

Ring resonator-based biosensors have found widespread application as the transducing principle in “lab-on-a-chip” platforms due to their sensitivity, small size and support for multiplexed sensing. Their sensitivity is, however, not inherently selective towards biomarkers, and surface functionalization of the sensors is key in transforming the sensitivity to be specific for a particular biomarker. There is currently no consensus on process parameters for optimized functionalization of these sensors. Moreover, the procedures are typically optimized on flat silicon oxide substrates as test systems prior to applying the procedure to the actual sensor. Here we present what is, to our knowledge, the first comparison of optimization of silanization on flat silicon oxide substrates to results of protein capture on sensors where all parameters of two conjugation protocols are tested on both platforms. The conjugation protocols differed in the chosen silanization solvents and protein immobilization strategy. The data show that selection of acetic acid as the solvent in the silanization step generally yields a higher protein binding capacity for C-reactive protein (CRP) onto anti-CRP functionalized ring resonator sensors than using ethanol as the solvent. Furthermore, using the BS3 linker resulted in more consistent protein binding capacity across the silanization parameters tested. Overall, the data indicate that selection of parameters in the silanization and immobilization protocols harbor potential for improved biosensor binding capacity and should therefore be included as an essential part of the biosensor development process.

Microfluidics for pharmaceutical nanoparticle fabrication: The truth and the myth

Using micro-sized channels to manipulate fluids is the essence of microfluidics which has wide applications from analytical chemistry to material science and cell biology research. Recently, using microfluidic-based devices for pharmaceutical research, in particular for the fabrication of micro- and nano-particles, has emerged as a new area of interest. The particles that can be prepared by microfluidic devices can range from micron size droplet-based emulsions to nano-sized drug loaded polymeric particles. Microfluidic technology poses unique advantages in terms of the high precision of the mixing regimes and control of fluids involved in formulation preparation. As a result of this, monodispersity of the particles prepared by microfluidics is often recognised as being a particularly advantageous feature in comparison to those prepared by conventional large-scale mixing methods. However, there is a range of practical drawbacks and challenges of using microfluidics as a direct micron- and nano-particle manufacturing method. Technological advances are still required before this type of processing can be translated for application by the pharmaceutical industry. This review focuses specifically on the application of microfluidics for pharmaceutical solid nanoparticle preparation and discusses the theoretical foundation of using the nanoprecipitation principle to generate particles and how this is translated into microfluidic design and operation.

Water Droplets Translocation and Fission in a 3D Bi-Planar Multifurcated T-Junction Microchannels

Droplet fission has gained notable interest in drug delivery applications due to its ability to perform parallel operations in single device. Hitherto, droplet flow behavior in a 3D constriction was scarcely investigated. This study aims to investigate droplets fission inside a 3D bi-planar multifurcated microfluidic device. The flow behavior and droplet size distribution were studied in trifurcated microchannels using distilled water as dispersed phase (1 mPa·s) and olive oil (68 mPa·s) as continuous phase. Various sizes of subordinate daughter droplets were manipulated passively through the modulation of flowrate ratio (Q) (0.15 < Q < 3.33). Overall, we found droplet size coefficient of variations (CV%) ranging from 0.72% to 69%. Highly monodispersed droplets were formed at the upstream T-junction (CV% < 2%) while the droplet fission process was unstable at higher flowrate ratio (Q > 0.4) as they travel downstream (1.5% < CV% < 69%) to splitting junctions. Complex responses to the non-monotonic behavior of mean droplet size was found at the downstream boundaries, which arose from the deformations under nonuniform flow condition. CFD was used as a tool to study the preliminary maximum velocity (Umax) profile for the symmetrical (0.01334 m/s < Umax < 0.0153 m/s) and asymmetrical branched channels (0.0223 m/s< Umax < 0.00438 m/s), thus complementing the experimental model studies.

A self-calibrating and multiplexed electrochemical lab-on-a-chip for cell culture analysis and high-resolution imaging

In vitro analysis requires cell proliferation in conditions close to physiological ones. Lab-on-a-chip (LoC) devices simplify, miniaturize and automate traditional protocols, with the advantages of being less expensive and faster due to their shorter diffusion distances. The main limitation of current LoCs is still the control of the culture conditions. Most LoCs employ off-chip equipment to determine cell culture activity, which confers limited monitoring capacity. The few systems integrating transducers on-chip present important functional problems mostly associated with the attachment of biomolecules to the transducer surface (i.e., biofouling) and the impossibility of re-calibrating the sensors during cell culturing. This limitation is addressed in the present LoC containing a network of micro-channels and micro-chambers, which allows (i) cell seeding and cultivation, avoiding biofouling risk, (ii) multiplexed analysis of cell culture, reactivation and recalibration of the (bio)sensors without compromising cell viability, (iii) cell imaging and (iv) reference electrode compartmentalization to guarantee stability. The activity of the culture is monitored with four independent electrochemical micro-electrodes for glucose, hydrogen peroxide, conductivity and oxidation reduction potential. Electrochemical analysis is complemented with high-resolution confocal microscopy analysis. This paper demonstrates the suitability of the current configuration for cell culture monitoring and future applications in drug screening or organ-on-a-chip development.

The Microfluidic Technique and the Manufacturing of Polysaccharide Nanoparticles

The microfluidic technique has emerged as a promising tool to accelerate the clinical translation of nanoparticles, and its application affects several aspects, such as the production of nanoparticles and the in vitro characterization in the microenvironment, mimicking in vivo conditions. This review covers the general aspects of the microfluidic technique and its application in several fields, such as the synthesis, recovering, and samples analysis of nanoparticles, and in vitro characterization and their in vivo application. Among these, advantages in the production of polymeric nanoparticles in a well-controlled, reproducible, and high-throughput manner have been highlighted, and detailed descriptions of microfluidic devices broadly used for the synthesis of polysaccharide nanoparticles have been provided. These nanoparticulate systems have drawn attention as drug delivery vehicles over many years; nevertheless, their synthesis using the microfluidic technique is still largely unexplored. This review deals with the use of the microfluidic technique for the synthesis of polysaccharide nanoparticles; evaluating features of the most studied polysaccharide drug carriers, such as chitosan, hyaluronic acid, and alginate polymers. The critical assessment of the most recent research published in literature allows us to assume that microfluidics will play an important role in the discovery and clinical translation of nanoplatforms.

Noodle based analytical devices for cost effective green chemical analysis

Noodle based analytical devices are proposed for cost effective green chemical analysis. Two noodle based analytical platforms have been examined. Conditions for flow with laminar behaviors could be established. Detection may be via a webcam camera or a flatbed scanner. Acid-base reactions were chosen as a model study. The assays of acetic acid and sodium hydroxide were investigated. Apart from bromothymol blue, simple aqueous extract of butterfly pea flower was used as a natural reagent. Another model was the assay of copper (Cu²⁺) which was based on the redox reaction of copper (Cu²⁺) with iodide to produce tri-iodide forming brown/black product with starch which already exists in the noodle platform. Demonstration to apply the noodle platforms for real samples was made.

Numerical and Experimental Study on Mixing Performances of Simple and Vortex Micro T-Mixers

Vortex flow increases the interface area of fluid streams by stretching along with providing continuous stirring action to the fluids in micromixers. In this study, experimental and numerical analyses on a design of micromixer that creates vortex flow were carried out, and the mixing performance was compared with a simple micro T-mixer. In the vortex micro T-mixer, the height of the inlet channels is half of the height of the main mixing channel. The inlet channel connects to the main mixing channel (micromixer) at the one end at an offset position in a fashion that creates vortex flow. In the simple micro T-mixer, the height of the inlet channels is equal to the height of the channel after connection (main mixing channel). Mixing of fluids and flow field have been analyzed for Reynolds numbers in a range from 1–80. The study has been further extended to planar serpentine microchannels, which were combined with a simple and a vortex T-junction, to evaluate and verify their mixing performances. The mixing performance of the vortex T-mixer is higher than the simple T-mixer and significantly increases with the Reynolds number. The design is promising for efficiently increasing mixing simply at the T-junction and can be applied to all micromixers.

Particle Manipulation by Optical Forces in Microfluidic Devices

Since the pioneering work of Ashkin and coworkers, back in 1970, optical manipulation gained an increasing interest among the scientific community. Indeed, the advantages and the possibilities of this technique are unsubtle, allowing for the manipulation of small particles with a broad spectrum of dimensions (nanometers to micrometers size), with no physical contact and without affecting the sample viability. Thus, optical manipulation rapidly found a large set of applications in different fields, such as cell biology, biophysics, and genetics. Moreover, large benefits followed the combination of optical manipulation and microfluidic channels, adding to optical manipulation the advantages of microfluidics, such as a continuous sample replacement and therefore high throughput and automatic sample processing. In this work, we will discuss the state of the art of these optofluidic devices, where optical manipulation is used in combination with microfluidic devices. We will distinguish on the optical method implemented and three main categories will be presented and explored: (i) a single highly focused beam used to manipulate the sample, (ii) one or more diverging beams imping on the sample, or (iii) evanescent wave based manipulation.

Innovative methods for biomarker discovery in the evaluation and development of cancer precision therapies

The discovery of biomarkers able to detect cancer at an early stage, to evaluate its aggressiveness, and to predict the response to therapy remains a major challenge in clinical oncology and precision medicine. In this review, we summarize recent achievements in the discovery and development of cancer biomarkers. We also highlight emerging innovative methods in biomarker discovery and provide insights into the challenges faced in their evaluation and validation.

Lab-on-a-chip device made by autohesion-bonded polymers

Polymers have the obvious advantages of flexibility in design and cost effectiveness to fabricate a lab-on-a-chip (LOC) device. Polyether ether ketone (PEEK) in particular is very attractive choice as it adds biocompatibility in addition to the possibility of hematic sealing in a 3D design. Hereby, we extend our previous successful technology of autohesive hermetic bonding of medical implants into lab-on-a-chip devices. We explore a conceptual 3D micro channels design with hermetic potential using PEEK and PS sheets. A hermetic and mechanically strong (through tensile test) 3D multilayer device was obtained using plasma treatment with oxygen and methane as precursors followed by pressing at temperature near of T_g + 20 of the polymer with the lowest T_g (PS). This nanotexturing technique is also used to facilitate thermal and mechanical stability of the microchannels for microfluidic applications. X-ray tomography measurements showed that 3D polymer made chips, at certain plasma and press bonding conditions, have structural integrity and no deformation were detected in channels shape post thermal pressing process. The dimension stability of channels and reservoirs and the rigid interfacial region at PEEK-PS make this chip design attractive and feasible for advanced lab-on-a-chip applications.

Coalescence Processes of Droplets and Liquid Marbles

The coalescence process of droplets and, more recently, of liquid marbles, has become one of the most essential manipulation schemes in digital microfluidics. This process is indispensable for realising microfluidic functions such as mixing and reactions at microscale. This paper reviews previous studies on droplet coalescence, paying particular attention to the coalescence of liquid marbles. Four coalescence systems have been reviewed, namely, the coalescence of two droplets freely suspended in a fluid; the coalescence of two sessile droplets on a solid substrate; the coalescence of a falling droplet and a sessile droplet on a solid substrate; and liquid marble coalescence. The review is presented according to the dynamic behaviors, physical mechanisms and experimental parameters of the coalescence process. It also provides a systematic overview of how the coalescence process of droplets and liquid marbles could be induced and manipulated using external energy. In addition, the practical applications of liquid marble coalescence as a novel microreactor are highlighted. Finally, future perspectives on the investigation of the coalescence process of liquid marbles are proposed. This review aims to facilitate better understanding of the coalescence of droplets and of liquid marbles as well as to shed new insight on future studies.

Rapid, Self-driven Liquid Mixing on Open-Surface Microfluidic Platforms

Self-driven surface micromixers (SDSM) relying on patterned-wettability technology provide an elegant solution for low-cost, point-of-care (POC) devices and lab-on-a-chip (LOC) applications. We present a SDSM fabricated by strategically patterning three wettable wedge-shaped tracks onto a non-wettable, flat surface. This SDSM operates by harnessing the wettability contrast and the geometry of the patterns to promote mixing of small liquid volumes (µL droplets) through a combination of coalescence and Laplace pressure-driven flow. Liquid droplets dispensed on two juxtaposed branches are transported to a coalescence station, where they merge after the accumulated volumes exceed a threshold. Further mixing occurs during capillary-driven, advective transport of the combined liquid over the third wettable track. Planar, non-wettable "islands" of different shapes are also laid on this third track to alter the flow in such a way that mixing is augmented. Several SDSM designs, each with a unique combination of island shapes and positions, are tested, providing a greater understanding of the different mixing regimes on these surfaces. The study offers design insights for developing low-cost surface microfluidic mixing devices on open substrates.

Development of an integrated microfluidic solid-phase extraction and electrophoresis device

This study focuses on the design and fabrication of a microfluidic platform that integrates solid-phase extraction (SPE) and microchip electrophoresis (μCE) on a single device. The integrated chip is a multi-layer structure consisting of polydimethylsiloxane valves with a peristaltic pump, and a porous polymer monolith in a thermoplastic layer. The valves and pump are fabricated using soft lithography to enable pressure-based fluid actuation. A porous polymer monolith column is synthesized in the SPE unit using UV photopolymerization of a mixture consisting of monomer, cross-linker, photoinitiator, and porogens. The hydrophobic, porous structure of the monolith allows protein retention with good through flow. The functionality of the integrated device in terms of pressure-controlled flow, protein retention and elution, on-chip enrichment, and separation is evaluated using ferritin (Fer). Fluorescently labeled Fer is enriched ∼80-fold on a reversed-phase monolith from an initial concentration of 100 nM. A five-valve peristaltic pump produces higher flow rates and a narrower Fer elution peak than a three-valve pump operated under similar conditions. Moreover, the preconcentration capability of the SPE unit is demonstrated through μCE of enriched Fer and two model peptides in the integrated system. FA, GGYR, and Fer are concentrated 4-, 12-, and 50-fold, respectively. The loading capacity of the polymer monolith is 56 fmol (25 ng) for Fer. This device lays the foundation for integrated systems that can be used to analyze various disease biomarkers.

Manufacturing Methods for Liposome Adjuvants

A wide range of studies have shown that liposomes can act as suitable adjuvants for a range of vaccine antigens. Properties such as their amphiphilic character and biphasic nature allow them to incorporate antigens within the lipid bilayer, on the surface, or encapsulated within the inner core. However, appropriate methods for the manufacture of liposomes are limited and this has resulted in issues with cost, supply, and wider scale application of these systems. Within this chapter we explore manufacturing processes that can be used for the production of liposomal adjuvants, and we outline new manufacturing methods can that offer fast, scalable, and cost-effective production of liposomal adjuvants.

Spontaneous transfer of droplets across microfluidic laminar interfaces

The precise manipulation of droplets in microfluidics has revolutionized a myriad of drop-based technologies, such as multiple emulsion preparation, drop fusion, drop fission, drop trapping and drop sorting, which offer promising new opportunities in chemical and biological fields. In this paper, we present an interfacial-tension-directed strategy for the migration of droplets across liquid-liquid laminar streams. By carefully controlling the interfacial energies, droplets of phase A are able to pass across the laminar interfaces of two immiscible fluids from phase B to phase C due to a positive spreading coefficient of phase C over phase B. To demonstrate this, we successfully perform the transfer of water droplets across an oil-oil laminar interface and the transfer of oil droplets across an oil-water laminar interface. The whole transfer process is spontaneous and only takes about 50 ms. We find that the fluid dynamics have an impact on the transfer processes. Only if the flowrate ratios are well matched will the droplets pass through the laminar interface successfully. This interfacial-tension-directed transfer of droplets provides a versatile procedure to make new structures and control microreactions as exemplified by the fabrication of giant unilamellar vesicles and cell-laden microgels.

Microfluidic platforms for DNA methylation analysis

In the field of genetics, epigenetics is the study of changes in gene expression without any change in DNA sequences. Chemical base modification in DNA by DNA methyltransferase, and specifically methylation, has been well studied as the main mechanism of epigenetics. Therefore, the determination of DNA methylation of, for example, 5'-methylcytosine in the CpG sequence in mammals has attracted attention because it should prove valuable in a wide range of research fields including diagnosis, drug discovery, and therapy. Methylated DNA bases and DNA methyltransferase activity are analyzed using conventional methods; however, these methods are time-consuming and require complex multiple operations. Therefore, new methods and devices for DNA methylation analysis are now being actively developed. Furthermore, microfluidic technology has also been applied to DNA methylation analysis because the microfluidic platform offers the promising advantage of making it possible to perform thousands of DNA methylation reactions in small reaction volumes, resulting in a high-throughput analysis with high sensitivity. This review discusses epigenetics and the microfluidic platforms developed for DNA methylation analysis.

Customisable 3D printed microfluidics for integrated analysis and optimisation

The formation of smart Lab-on-a-Chip (LOC) devices featuring integrated sensing optics is currently hindered by convoluted and expensive manufacturing procedures. In this work, a series of 3D-printed LOC devices were designed and manufactured via stereolithography (SL) in a matter of hours. The spectroscopic performance of a variety of optical fibre combinations were tested, and the optimum path length for performing Ultraviolet-visible (UV-vis) spectroscopy determined. The information gained in these trials was then used in a reaction optimisation for the formation of carvone semicarbazone. The production of high resolution surface channels (100-500 μm) means that these devices were capable of handling a wide range of concentrations (9 μM-38 mM), and are ideally suited to both analyte detection and process optimisation. This ability to tailor the chip design and its integrated features as a direct result of the reaction being assessed, at such a low time and cost penalty greatly increases the user's ability to optimise both their device and reaction. As a result of the information gained in this investigation, we are able to report the first instance of a 3D-printed LOC device with fully integrated, in-line monitoring capabilities via the use of embedded optical fibres capable of performing UV-vis spectroscopy directly inside micro channels.

Invited Review: Toxicoproteomics: Proteomics Applied to Toxicology and Pathology

Global measurement of proteins and their many attributes in tissues and biofluids defines the field of proteomics. Toxicoproteomics, as part of the larger field of toxicogenomics, seeks to identify critical proteins and pathways in biological systems that are affected by and respond to adverse chemical and environmental exposures using global protein expression technologies. Toxicoproteomics integrates 3 disciplinary areas: traditional toxicology and pathology, differential protein and gene expression analysis, and systems biology. Key topics to be reviewed are the evolution of proteomics, proteomic technology platforms and their capabilities with exemplary studies from biology and medicine, a review of over 50 recent studies applying proteomic analysis to toxicological research, and the recent development of databases designed to integrate -Omics technologies with toxicology and pathology. Proteomics is examined for its potential in discovery of new biomarkers and toxicity signatures, in mapping serum, plasma, and other biofluid proteomes, and in parallel proteomic and transcriptomic studies. The new field of toxicoproteomics is uniquely positioned toward an expanded understanding of protein expression during toxicity and environmental disease for the advancement of public health.

Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication

The uptake of microfluidics by the wider scientific community has been limited by the fabrication barrier created by the skills and equipment required for the production of traditional microfluidic devices. Here we present simple 3D printed microfluidic devices using an inexpensive and readily accessible printer with commercially available printer materials. We demonstrate that previously reported limitations of transparency and fidelity have been overcome, whilst devices capable of operating at pressures in excess of 2000 kPa illustrate that leakage issues have also been resolved. The utility of the 3D printed microfluidic devices is illustrated by encapsulating dental pulp stem cells within alginate droplets; cell viability assays show the vast majority of cells remain live, and device transparency is sufficient for single cell imaging. The accessibility of these devices is further enhanced through fabrication of integrated ports and by the introduction of a Lego^®-like modular system facilitating rapid prototyping whilst offering the potential for novices to build microfluidic systems from a database of microfluidic components.

The end of the (forensic science) world as we know it? The example of trace evidence

The dominant conception of forensic science as a patchwork of disciplines primarily assisting the criminal justice system (i.e. forensics) is in crisis or at least shows a series of anomalies and serious limitations. In recent years, symptoms of the crisis have been discussed in a number of reports by various commentators, without a doubt epitomized by the 2009 report by the US National Academies of Sciences (NAS 2009 Strengthening forensic science in the United States: a path forward). Although needed, but viewed as the solution to these drawbacks, the almost generalized adoption of stricter business models in forensic science casework compounded with ever-increasing normative and compliance processes not only place additional pressures on a discipline that already appears in difficulty, but also induce more fragmentation of the different forensic science tasks, a tenet many times denounced by the same NAS report and other similar reviews. One may ask whether these issues are not simply the result of an unfit paradigm. If this is the case, the current problems faced by forensic science may indicate future significant changes for the discipline. To facilitate broader discussion this presentation focuses on trace evidence, an area that is seminal to forensic science both for epistemological and historical reasons. There is, however, little doubt that this area is currently under siege worldwide. Current and future challenges faced by trace evidence are discussed along with some possible answers. The current situation ultimately presents some significant opportunities to re-invent not only trace evidence but also forensic science. Ultimately, a distinctive, more robust and more reliable science may emerge through rethinking the forensics paradigm built on specialisms, revisiting fundamental forensic science principles and adapting them to the twenty-first century.

Materiomics for Oral Disease Diagnostics and Personal Health Monitoring: Designer Biomaterials for the Next Generation Biomarkers

We live in exciting times for a new generation of biomarkers being enabled by advances in the design and use of biomaterials for medical and clinical applications, from nano- to macro-materials, and protein to tissue. Key challenges arise, however, due to both scientific complexity and compatibility of the interface of biology and engineered materials. The linking of mechanisms across scales by using a materials science approach to provide structure-process-property relations characterizes the emerging field of 'materiomics,' which offers enormous promise to provide the hitherto missing tools for biomaterial development for clinical diagnostics and the next generation biomarker applications towards personal health monitoring. Put in other words, the emerging field of materiomics represents an essentially systematic approach to the investigation of biological material systems, integrating natural functions and processes with traditional materials science perspectives. Here we outline how materiomics provides a game-changing technology platform for disruptive innovation in biomaterial science to enable the design of tailored and functional biomaterials--particularly, the design and screening of DNA aptamers for targeting biomarkers related to oral diseases and oral health monitoring. Rigorous and complementary computational modeling and experimental techniques will provide an efficient means to develop new clinical technologies in silico, greatly accelerating the translation of materiomics-driven oral health diagnostics from concept to practice in the clinic.

On-demand in situ generation of oxygen in a nanofluidic embedded planar microband electrochemical reactor

In situ generation of reagents and their subsequent use downstream presents new opportunities to amplify the utility of nanofluidic devices by exploiting the confined geometry to address mass transport limitations on reaction kinetics and efficiency. Oxygen, an inherently valuable reactant, can be produced from electrolysis of water, a process that can be conveniently integrated within a nanofluidic system. Here, we construct and characterize a nanofluidic device consisting of a planar microband electrode embedded within a nanochannel for in situ electrochemical generation and optical monitoring of O₂. Fluorescein, a dye with a pH-sensitive emission intensity, was used to monitor the spatiotemporal characteristics of the oxidation of H₂O, using the co-produced H⁺. Application of anodic potentials at the nanochannel-embedded electrode results in a decrease in fluorescence intensity, which reflects the decreasing solution pH. A combination of fluorescence intensity and chronoamperometric response was used to quantitatively determine proton generation, and the H⁺/O₂ stoichiometry was then used to determine the concentration of the O₂ in the channel. Comparison of the experimental results to finite element simulations validates the use of fluorescein emission intensity to spectroscopically determine the local oxygen concentration in the nanochannel. By varying the applied potential, spatially averaged O₂ concentrations ranging from 0.13 to 0.41 mM were generated. The results demonstrate a convenient route to in situ modulation of the dissolved O₂ level in a nanofluidic device and the use of an optical probe to monitor its spatial and temporal distribution under flow conditions.

Size Control in the Nanoprecipitation Process of Stable Iodine (¹²⁷I) Using Microchannel Reactor-Optimization by Artificial Neural Networks

In this study, nanosuspension of stable iodine ((127)I) was prepared by nanoprecipitation process in microfluidic devices. Then, size of particles was optimized using artificial neural networks (ANNs) modeling. The size of prepared particles was evaluated by dynamic light scattering. The response surfaces obtained from ANNs model illustrated the determining effect of input variables (solvent and antisolvent flow rate, surfactant concentration, and solvent temperature) on the output variable (nanoparticle size). Comparing the 3D graphs revealed that solvent and antisolvent flow rate had reverse relation with size of nanoparticles. Also, those graphs indicated that the solvent temperature at low values had an indirect relation with size of stable iodine ((127)I) nanoparticles, while at the high values, a direct relation was observed. In addition, it was found that the effect of surfactant concentration on particle size in the nanosuspension of stable iodine ((127)I) was depended on the solvent temperature. Nanoprecipitation process of stable iodine (127I) and optimization of particle size using ANNs modeling.

Blood Draw Barriers for Treatment with Clozapine and Development of a Point-of-Care Monitoring Device

BACKGROUND

While clozapine (CLZ) is the most effective antipsychotic drug for schizophrenia treatment, it remains underused. In order to understand the barriers of frequent blood draws for white blood cell counts (WBCs) and clozapine levels, we developed a psychiatrist survey and began an integrative approach of designing a point-of-care device that could eventually have real-time monitoring with immediate results.

METHODS

We ascertained barriers related to CLZ management and the acceptance of possible solutions by sending an anonymous survey to physicians in psychiatric practice (n=860). In parallel, we tested CLZ sensing using a prototype point-of-care monitoring device.

RESULTS

255 responses were included in the survey results. The two barriers receiving mean scores with the highest agreement as being a significant barrier were patient nonadherence to blood work and blood work's burden on the patient (out of 28). Among nine solutions, the ability to obtain lab results in the physician's office or pharmacy was top ranked (mean±sd Likert scale [4.0±1.0]). Physicians responded that a point-of-care device to measure blood levels and WBCs would improve care and increase CLZ use. Residents ranked point-of-care devices higher than older physicians (4.07±0.87 vs. 3.47±1.08, p<0.0001). Also, the prototype device was able to detect CLZ reliably in 1.6, 8.2, and 16.3 μg/mL buffered solutions.

DISCUSSION

Survey results demonstrate physicians' desire for point-of-care monitoring technology, particularly among younger prescribers. Prototype sensor results identify that CLZ can be detected and integrated for future device development. Future development will also include integration of WBCs for a complete detection device.

Enhanced capture of magnetic microbeads using combination of reduced magnetic field strength and sequentially switched electroosmotic flow--a numerical study

Magnetophoretic immunoassay is a widely used technique in lab-on-chip systems for detection and isolation of target cells, pathogens, and biomolecules. In this method, target pathogens (antigens) bind to specific antibodies coated on magnetic microbeads (mMBs) which are then separated using an external magnetic field for further analysis. Better capture of mMB is important for improving the sensitivity and performance of magnetophoretic assay. The objective of this study was to develop a numerical model of magnetophoretic separation in electroosmotic flow (EOF) using magnetic field generated by a miniaturized magnet and to evaluate the capture efficiency (CE) of the mMBs. A finite-volume solver was used to compute the trajectory of mMBs under the coupled effects of EOF and external magnetic field. The effect of steady and time varying (switching) electric fields (150-450 V/cm) on the CE was studied under reduced magnetic field strength. During switching, the electric potential at the inlet and outlet of the microchannel was reversed or switched, causing reversal in flow direction. The CE was a function of the momentum of the mMB in EOF and the applied magnetic field strength. By switching the electric field, CE increased from 75% (for steady electric field) to 95% for lower electric fields (150-200 V/cm) and from 35% to 47.5% for higher electric fields (400-450 V/cm). The CE was lower at higher EOF electric fields because the momentum of the mMB overcame the external magnetic force. Switching allowed improved CE due to the reversal and decrease in EOF velocity and increase in mMB residence time under the reduced magnetic field strength. These improvements in CE, particularly at higher electric fields, made sequential switching of EOF an efficient separation technique of mMBs for use in high throughput magnetophoretic immunoassay devices. The reduced size of the magnet, along with the efficient mMB separation technique of switching can lead to the development of portable device for detection of target cells, pathogens, and biomolecules.

On-chip gradient generation in 256 microfluidic cell cultures: simulation and experimental validation

A microfluidic diffusion diluter was used to create a stable concentration gradient for dose response studies.

Non-photolithographic plastic-mold-based fabrication of cylindrical and multi-tiered poly(dimethylsiloxane) microchannels for biomimetic lab-on-a-chip applications

Cylindrical and multi-tiered PDMS microchannels were fabricated from two thermoplastic molds having large difference in glass transition temperatures, and were used for constructing LOC platforms mimicking human microvasculature and liver sinusoid.