Procedia Technology最新文献

The conventional microfluidic electrophoresis chip must be applied higher voltage, which limited the microminiaturization and integration. According to the principle of electrophoresis chip, a helix channel electrophoresis chip drove by low voltage was proposed. Some key techniques were researched, which include the bubble issue, optimization of the chip structure, low cost hydrophilic surface modification for the chip, design of miniaturized control and detection system. Test results shown the helix channel chip has better separation than the cross channel chip, and the sample can be successfully separated below 100 V voltage.

The objective of the present invention is to develop an ultrasensitive technique for the electro analysis of rape drug. A paper chip (EμPADs) was developed using nanocrystals (Nanocrys) of graphene-oxide and zeolites (Zeo-GO). Nanocrys modified EμPAD showed wide linear range 0.001 - 5 nM/ml and low detection limit of 0.00002 nM/ml. The developed sensor was tested in real time samples like alcoholic and non-alcoholic drinks and found good correlation (99%). Extensive development can be made for industrial translation of this fabricated device.

We theoretically study a three-layer continuum model of a surface acoustic wave sensor where the two overlayers are allowed to be viscoelastic. This case is particularly important in biosensing, where soft materials submerged in fluids are commonplace. From the general dispersion equation, we calculate the phase velocity shift and the wave attenuation. We show that there is a viscoelastic coupling between the overlayers which results in unintuitive behavior, e.g., the addition of viscous loading to a soft-film sensor can reduce the attenuation.

An amperometric sulfite biosensor was developed based on disposable screen printed electrodes (SPEs) and sulfite oxidase (SOx) enzyme. The developed biosensor shows good sensitivity (62 nA/ppm), reproducibility (RSD = 4%; n = 5) and a linear range of 15-1000 ppm. The applicability of the biosensor for the analysis of sodium metabisulfite in shrimp farm samples was demonstrated successfully.

The need for new, easy-to-use, home and decentralised diagnostics is now greater than ever and it is rapidly becoming apparent that biosensors can contribute substantially to reducing healthcare costs. New thinking is crucial to finding effective solutions that deliver the high quality of life rightly demanded by our ever ageing population while leveraging technology to deliver this in a cost-effective manner. Several key drivers are catalysing change. Personalised medicine recognises that every individual is different and needs a tailor-made health package; these differences can only be identified with an appropriate suite of diagnostics. Individuals are increasing recognising that data about their bodies should be owned by them and that they should have the choice to use and supplement this information. This generates consumer choice and drives evidence-based payment, where the success of outcomes needs to be measured. Focus on the individual and their needs drives decentralisation and the possible radical restructuring of how we deliver health management. We already see “health rooms” in pharmacies, but the next step will be health rooms in your home, in your pocket or on your wrist. These advances are underpinned by technologies facilitating mobility and data processing, but at the core are rapid, convenient and easy ways to measure our body chemistries at the genomic, proteomic and metabolomic levels. This presentation will focus on meeting these challenges using paper-based electronics, polymers and integrated electrochemical systems to deliver inexpensive instruments for a wide range of bioanalytical applications. Approaches will be illustrated by multi-parametric monitoring for the management of diabetes, chronic kidney disease and stress, reversible and label-free affinity sensors for cancer markers and heart disease, aptasensors for pathogens and cancer cells, and robust microbial-differentiation arrays. Further development will result in cost reduction and a diversity of formats such as point-of-care tests, smart packaging, telemetric strips and print-on-demand analytical devices.

Commonly immunoassay using magnetic nanoparticles (MNP) are performed under the control of permanent magnet close to the micro-tube of reaction¹. Using a magnet gives a powerful method for driving MNP but remains unreliable or insufficient, for a fully integrated immunoassay on lab-on-chip. The aim of this study is to develop a novel lab-on-chip (Figure 1.B) for high efficient immunoassays to detect pathogenic bacteria with microcoils employed for trapping MNP during the biofunctionalization steps. Studies on bacteria are mainly based on E. Coly^2,3 which is a non-pathogenic bacteria and can be find everywhere. In our case we use ovalbumin which is defined as a biodefense model protein. The objectives are essentially to optimize their efficiency for biological recognition, by assuring a better bioactivity (antibodies-ovalbumin), and detect small concentrations of the targeted protein (∼10 pg/mL).

The fluidic microsystem is made of PDMS, which is micro-molded in SU8, it had channels with 50 μm height and 500 μm width. Microfluidic conditions permit a faster biofonctionnalisation step than in test tube and allow capture and detection of biological elements integrated in lab-on-chip.

Microcoils are electrodeposited on silicon using cupper. They are microfabricated with cupper wire of 10 μm height, 10 μm width, 10 μm space between wire and 45 spires. Microcoils are encapsulated in microfluidic chip by covering them with a spin-coated thin layers of PDMS. Microcoils give a local and efficient trapping of MNP and a fully integrated device.

Biological activity is studied respecting ELISA protocol with ovalbumin as protein of interest. To graft the primary antibody and protect the free area of MNP we used carboxylic as terminal group for grafting antibodies and BSA (Bovine Serum Albumin) for passivation (Figure 1.A). We characterize this method by measuring the intensity of the antibody of detection using FITC (Fluorescein isothiocynathe). Intensity is detected by fluorescent microscope connected to the microfluidic plateform and images are processed using a home-made script.

First we studied the response of immunoassays complex function of MNP size (200 nm, 300 nm and 500 nm), we confirmed that with a lower diameter we increase the intensity detected, following specific surface formula (1), (2), (3).

Regarding the magnetic force needed (depending of several parameters including magnetic field and parameters of the particle) and the intensity detected we selected 300 nm size of NPM.

We studied the response of immunoassays complex function of ovalbumin concentration. We realized different immunoassays by controlling MNP (Figure 1.C&D) in test tube and in microfluidic device using a magnet. The comparison between these two experiments allow us to show an improved limit of detection (L.O.D. = I₀ – 3 × σ_D