Point-of-Care (POC) diagnostics often fail to meet the market requirements of low cost and advanced functionality, and are often limited to lateral flow based serological diagnostics with reduced sensitivity and specificity. We report here on an integrated microfluidic absorbance measurement device fabricated by roll-to-roll (R2R) compatible manufacturing processes, suitable for low cost POC systems. It is a device exclusively made of foils and takes external light from a low cost LED and converts the point light source to a homogeneous light via a foil based optical filter at the bottom of the device. The light is converted to an electrical signal by an amorphous organic semiconductor (OSC) material, integrated with screen-printed carbon finger on top of the device for electrical measurement. As a proof of principle, we demonstrate DNA hybridization assay, where the target DNA is coupled to magnetic beads for absorbance measurement. The device successfully distinguishes between matched and mismatched DNA hybridization and can differentiate between 1 μM, 50 nM and 2.5 nM DNA target concentrations. The inherent characteristics of the substrates and R2R fabrication concept significantly reduce the cost, making it suitable for POC applications at resource-limited settings. 

Ultrasensitive measurements of intracellular ATP (intATP) based on the firefly luciferase reactions are frequently used to enumerate bacterial or mammalian cells. During clinical applications, extracellular ATP (extATP) should be depleted in biological samples since it interferes with intATP and affects the quantification of bacteria. The extATP can be eliminated by ATP-degrading enzymes but complete hydrolysis of extATP remains a challenge for today's commercial enzymes. The catalytic efficiency of ATP-degrading enzymes depends on enzyme characteristics, sample composition and the ability to deplete diphosphates, triphosphates and their complexes generated during the reaction. This phenomenon restricts the usage of bioluminescence-based ATP methods in clinical diagnostics. In light of this, we have developed a recombinant Shigella flexneri apyrase (RSFA) enzyme and analysed its ATP depletion potential with five commercial biochemical sources including potato apyrase, acid phosphatase, alkaline phosphatase, hexokinase and glycerol kinase. The RSFA revealed superior activity by completely eliminating the extracellular ATP and ATP-complexes, even in biological samples like urine and serum. Therefore, our results can potentially unwrap the chemical and bio-analytical applications of ATP-based bioluminescence tests to develop highly sensitive point-of-care diagnostics.

There is a growing demand for simple, affordable, reliable and quality-assured point-of-care (POC) diagnostics for use in resource-limited settings. Among the top ten leading causes of death worldwide, three are infectious diseases, namely, respiratory infections, HIV/AIDS and diarrheal diseases (World Health Organization 2012). Although high-quality diagnostic tests are available, these are often not available to patients in developing countries. While recent development in microfluidics and “lab-on-a-chip” devices has the potential to spur the development of protocols and affordable instruments for diagnosis of infectious disease at POC, integration of complex sample preparation and detection into automated molecular and cellular systems remain a bottleneck for implementation of these systems at resource-limited settings. Towards this, we describe here how low-cost optical drives can, with minor modifications, be turned into POC diagnostic platforms. A DVD drive is essentially a highly advanced and low-cost optical laser-scanning microscope, with the capability to deliver high-resolution images for biological applications. Furthermore, the inherent centrifugal force on rotational discs is elegantly used for sample preparation and integration. Hence, the merging of low-cost optical disc drives with centrifugal microfluidics is feasible concept for POC diagnostics, specifically designed to meet the needs at resource-limited settings.

Bioparticles such as mammalian cells and bacteria can be manipulated directly or indirectly for multiple applications such as sample preparation for diagnostic applications mainly up-concentration, enrichment & separation as well as immunoassay development. There are various active and passive microfluidic particle manipulation techniques where Acoustophoresis is a powerful technique showing high cell viability. The use of disposable glass capillaries for acoustophoresis, instead of cleanroom fabricated glass-silicon chip can potentially bring down the cost factor substantially, aiding the realization of this technique for real-world diagnostic devices. Unlike available chips and capillary-based microfluidic devices, we report milliliter-scale platform able to accommodate 1ml of a sample for acoustophoresis based processing on a market available glass capillary. Although it is presented as a generic platform but as a demonstration we have shown that polystyrene suspending medium sample can be processed with trapping efficiency of 87% and the up-concentration factor of 10 times in a flow through manner i.e., at 35µl/min. For stationary volume accommodation, this platform practically offers 50 times more sample handling capacity than most of the microfluidic setups. Furthermore, we have also shown that with diluted blood (0.6%) in a flow-through manner, 82% of the white blood cells (WBCs) per ml could be kept trapped. This milliliter platform could potentially be utilized for assisting in sample preparation, plasma separation as well as a flow-through immunoassay assay development for clinical diagnostic applications.

A small subset of HIV-1 infected individuals, the "Elite Controllers" (EC), can control viral replication and restrain progression to immunodeficiency without antiretroviral therapy (ART). In this study, a cross-sectional transcriptomics and targeted proteomics analysis were performed in a well-defined Swedish cohort of untreated EC (n = 19), treatment naive patients with viremia (VP, n = 32) and HIV-1-negative healthy controls (HC, n = 23). The blood transcriptome identified 151 protein-coding genes that were differentially expressed (DE) in VP compared to EC. Genes like CXCR6 and SIGLEC1were downregulated in EC compared to VP. A definite distinction in gene expression between males and females among all patient-groups were observed. The gene expression profile between female EC and the healthy females was similar but did differ between male EC and healthy males. At targeted proteomics analysis, 90% (29/32) of VPs clustered together while EC and HC clustered separately from VP. Among the soluble factors, 33 were distinctive to be statistically significant (False discovery rate = 0.02). Cell surface receptor signaling pathway, programmed cell death, response to cytokine and cytokine-mediated signaling seem to synergistically play an essential role in HIV-1 control in EC.

A fiber probe traps single micrometer-particles by fluid suction into a hollow microstructure and enables optical identification by the fluorescence light collected in a fiber core. The probe finds applications in life-science and environmental monitoring.

Aims: Chronic kidney disease (CKD) leads to impairment of immune cell function. Given the potential role of basophils in the pathogenesis of CKD, we aimed to study the basophil responsiveness towards microbial antigen exposure, judged as adhesion molecule expression and degranulation, in CKD patients on hemodialysis. Materials and methods: We selected markers linked to two crucial biological phases: the transmigration and degranulation processes, respectively. For the transmigration process, we selected the adhesion molecules CD11b, active CD11b epitope, and CD62L and for the degranulation process CD203c (piecemeal degranulation marker), CD63 (degranulation marker), and CD300a (inhibitory marker of degranulation). We measured basophil responsiveness after stimulation of different activation pathways in basophils using lipopolysaccharide (LPS), peptidoglycan (PGN), formyl-methyinoyl-leucyl-phenylalanine (fMLP), and anti-FceRI-ab. Results: The expression of CD63 in basophils following activation by fMLP was significantly higher in the patient group compared to matched healthy controls, but no differences were observed after activation by anti-Fc.RI. CD300a expression was significantly higher in patients following activation by fMLP and anti-Fc.RI, and the active epitope CD11b expression was significantly higher in patients after LPS activation. In addition, we found that CD62L was not shed from the cell surface after activation with LPS and fMLP. A slight downregulation was noted after activation with anti-Fc.RI in healthy controls. Conclusion: Together, these data demonstrate that basophil functions related to adhesion and degranulation are altered in CKD patients on hemodialysis, which indicates a potential role for the basophil in the pathogenesis of complications related to infections.

Background: Bloodstream infections (BSI) remain a major challenge with high mortality rate, with an incidence that is increasing worldwide. Early treatment with appropriate therapy can reduce BSI-related morbidity and mortality. However, despite recent progress in molecular based assays, complex sample preparation steps have become critical roadblock for a greater expansion of molecular assays. Here, we report a size based, label-free, bacteria separation from whole blood using elasto-inertial microfluidics.

Results: In elasto-inertial microfluidics, the viscoelastic flow enables size based migration of blood cells into a non- Newtonian solution, while smaller bacteria remain in the streamline of the blood sample entrance and can be sepa- rated. We first optimized the flow conditions using particles, and show continuous separation of 5 μm particles from 2 μm at a yield of 95% for 5 μm particle and 93% for 2 μm particles at respective outlets. Next, bacteria were continu- ously separated at an efficiency of 76% from undiluted whole blood sample.

Conclusion: We demonstrate separation of bacteria from undiluted while blood using elasto-inertial microfluidics. The label-free, passive bacteria preparation method has a great potential for downstream phenotypic and molecular analysis of bacteria. 

Flow cytometry is currently the gold standard for analysis of cells in the medical laboratory and biomedical research. Fuelled by the need of point-of-care diagnosis, a significant effort has been made to miniaturize and reduce cost of flow cytometers. However, despite recent advances, current microsystems remain less versatile and much slower than their large-scale counterparts. In this work, an all-silica fibre microflow cytometer is presented that measures fluorescence and scattering from particles and cells. It integrates cell transport in circular capillaries and light delivery by optical fibres. Single-stream cell focusing is performed by Elasto-inertial microfluidics to guarantee accurate and sensitive detection. The capability of this technique is extended to high flow rates (up to 800 mu l/min), enabling a throughput of 2500 particles/s. The robust, portable and low-cost system described here could be the basis for a point-of-care flow cytometer with a performance comparable to commercial systems.

Bacterial blood stream infection (BSI) potentially leads to life-threatening clinical conditions and medical emergencies such as severe sepsis, septic shock, and multi organ failure syndrome. Blood culturing is currently the gold standard for the identification of microorganisms and, although it has been automated over the decade, the process still requires 24–72 h to complete. This long turnaround time, especially for the identification of antimicrobial resistance, is driving the development of rapid molecular diagnostic methods. Rapid detection of microbial pathogens in blood related to bloodstream infections will allow the clinician to decide on or adjust the antimicrobial therapy potentially reducing the morbidity, mortality, and economic burden associated with BSI. For molecular-based methods, there is a lot to gain from an improved and straightforward method for isolation of bacteria from whole blood for downstream processing. We describe a microfluidic-based sample-preparation approach that rapidly and selectively lyses all blood cells while it extracts intact bacteria for downstream analysis. Whole blood is exposed to a mild detergent, which lyses most blood cells, and then to osmotic shock using deionized water, which eliminates the remaining white blood cells. The recovered bacteria are 100% viable, which opens up possibilities for performing drug susceptibility tests and for nucleic-acid-based molecular identification. © Springer Science+Business Media LLC 2017.