Currently, fluidic control in microdevices is mainly achieved either by external pumps and valves, which are expensive and bulky, or by valves integrated in the chip. Numerous types of internal valves or actuation methods have been proposed, but they generally impose difficult compromises between performance and fabrication complexity. We propose here a new paradigm for actuation in microfluidic devices based on rigid or semi-rigid walls with transversal dimensions of hundreds of micrometres that are able to slide within a microfluidic chip and to intersect microchannels with hand-driven or translation stage-based actuation.
View Article and Find Full Text PDFAn original method of monolith impregnation in microsystem for the analysis of radionuclides in nitric acid is reported. Three microcolumns made of monolith poly(AMA-co-EDMA) were impregnated in COC microsystems. The robustness of the microsystems in nitric acid media until 8 M was demonstrated.
View Article and Find Full Text PDFVolume is an important parameter regarding physiological and pathological characteristics of neurons at different time scales. Neurons are quite unique cells regarding their extended ramified morphologies and consequently raise several methodological challenges for volume measurement. In the particular case of in vitro neuronal growth, the chosen methodology should include sub-micrometric axial resolution combined with full-field observation on time scales from minutes to hours or days.
View Article and Find Full Text PDFThe use of a centrifugal microfluidic platform is an alternative to classical chromatographic procedures for radiochemistry. An ion-exchange support with respect to the light-addressable process of elaboration is specifically designed to be incorporated as a radiochemical sample preparation module in centrifugal microsystem devices. This paper presents a systematic study of the synthesis of the polymeric porous monolith poly(ethylene glycol methacrylate-co-allyl methacrylate) used as a solid-phase support and the versatile and robust photografting process of the monolith based on thiol-ene click chemistry.
View Article and Find Full Text PDFThe nanofabrication of a nanomachined holed structure localized on the free end of a microcantilever is here presented, as a new tool to design micro-resonators with enhanced mass sensitivity. The proposed method allows both for the reduction of the sensor oscillating mass and the increment of the resonance frequency, without decreasing the active surface of the device. A theoretical analysis based on the Rayleigh method was developed to predict resonance frequency, effective mass, and effective stiffness of nanomachined holed microresonators.
View Article and Find Full Text PDFIn this work a polymer lab-on-a-chip (LOC), fabricated through MEMS technology, was employed to execute a genetic protocol for the Single Nucleotide Polymorphisms (SNPs) detection. The LOC was made in Poly (methyl methacrylate) (PMMA) and has two levels: the lower one for the insertion and mixing of the reagents, the upper one for the interfacing with the DNA microarray chip. The hereditary hearing loss was chosen as case of study, since the demand for testing such a particular disorder is high and genetics behind the condition is quite clear.
View Article and Find Full Text PDFMiniaturization of analytical procedures has a significant impact on diagnostic testing since it provides several advantages such as: reduced sample and reagent consumption, shorter analysis time and less sample handling. Lab-on-a-chip (LoC), usually silicon, glass, or silicon-glass, or polymer disposable cartridges, which are produced using techniques inherited from the microelectronics industry, could perform and integrate the operations needed to carry out biochemical analysis through the mechanical realization of a dedicated instrument. Analytical devices based on miniaturized platforms like LoC may provide an important contribution to the diagnosis of high prevalence and rare diseases.
View Article and Find Full Text PDFTo date control strategies in detecting anabolic agents for promoting growth of food producing animals are mainly related to screening techniques based on immunochemical and physiochemical methods, whose major limit is represented by relative low analytical sensitivity. As a consequence, consumers are currently exposed to molecules with potential carcinogenic effects such as 17β-estradiol, the most powerful substance with estrogenic effect. Therefore, high analytical sensitivity screening and confirmatory methods are required, coupling easiness of use and efficiency.
View Article and Find Full Text PDFMycotoxins, such as aflatoxins and ochratoxin A, are presently considered as the most important chronic dietary risk factor, more than food additives or pesticide residues. Therefore, the serious health and economic consequences of mycotoxin contamination have created the need for rapid, sensitive, and reliable techniques to detect such dangerous molecules within foodstuffs. We here report on the development of an innovative immunosensing method for mycotoxin detection, based on antibody-immobilized microcantilever resonators, a promising label free biosensing technique.
View Article and Find Full Text PDFMicrocantilever based oscillators have shown the possibility of highly sensitive label-free detection by allowing the transduction of a target mass into a resonant frequency shift. Most of such measurements were performed in air or vacuum environment, since immersion in liquid dramatically deteriorates the mechanical response of the sensor. Besides, the integration of microcantilever detection in a microfluidic platform appears a highly performing technological solution to exploit real time monitoring of biomolecular interactions, while limiting sample handling and promoting portability and automation of routine diagnostic tests (Point-Of-Care devices).
View Article and Find Full Text PDFLab-on-chips (LOCs) are critical systems that have been introduced to speed up and reduce the cost of traditional, laborious and extensive analyses in biological and biomedical fields. These ambitious and challenging issues ask for multi-disciplinary competences that range from engineering to biology. Starting from the aim to integrate microarray technology and microfluidic devices, a complex multilevel analysis platform has been designed, fabricated and tested (All rights reserved-IT Patent number TO2009A000915).
View Article and Find Full Text PDFMicrocantilever biosensors have been proposed in the last years as very sensitive mass detectors, but few works focused on the precision and specificity of such tools. We measured the repeatability and reproducibility of our cantilever-based system, proponing the combination of results coming from both the first and second mode of vibration. Then, we optimized two biodesigns (a receptor-based and an antibody-based) to the detection of Angiopoietin-1, a possible marker in tumor progression.
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