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1.
Talanta ; 193: 44-50, 2019 Feb 01.
Article in English | MEDLINE | ID: mdl-30368296

ABSTRACT

Polydimethylsiloxane (PDMS) is a well-known biocompatible polymer employed for many applications in the biomedical field. In this study, the biocompatibility and versatility of PDMS was tested setting up a microdevice devoted to the purification and analysis of nucleic acids. The PDMS microdevice was demonstrated to successfully fulfill all requirements of genetic analyses such as genotyping and pathogen DNA identification both in multiplex and real-time PCR, suggesting the possibility to carry out a molecular test directly on-chip. Moreover, the PDMS microdevice was successfully applied to the purification and detection of disease biomarkers, such as microRNAs related to cancer or heart disease. On-chip microRNA purification was demonstrated starting from clinically relevant samples, i.e. plasma, serum, tissue biopsies. Significantly, the purification and the transcription of microRNA into cDNA occur in the same PDMS chamber, saving time and labor for the overall analysis. Again, the PDMS microdevice was confirmed as a notable candidate for compact, rapid, easy-to-use molecular tests.


Subject(s)
DNA/analysis , Dimethylpolysiloxanes/chemistry , Lab-On-A-Chip Devices , MicroRNAs/analysis , Biomarkers/analysis , Genotyping Techniques/instrumentation , Genotyping Techniques/methods , Humans , MicroRNAs/isolation & purification , Multiplex Polymerase Chain Reaction/instrumentation , Multiplex Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/instrumentation , Real-Time Polymerase Chain Reaction/methods , Staphylococcus aureus/genetics , Streptococcus pneumoniae/genetics
2.
Biophys Chem ; 229: 142-150, 2017 10.
Article in English | MEDLINE | ID: mdl-28465106

ABSTRACT

A reliable clinical assay based on circulating microRNAs (miRNAs) as biomarkers is highly required. Microdevices offer an attractive solution as a fast and inexpensive way of concentrating these biomarkers from a low sample volume. A previously developed polydimethylsiloxane (PDMS) microdevice able to purify and detect circulating miRNAs was here optimized. The optimization of the morphological and chemical surface properties by nanopatterning and functionalization is presented. Surfaces were firstly characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), fluorescamine assay and s-SDTB (sulphosuccinimidyl-4-o-(4,4-dimethoxytrityl) butyrate) assay and subsequently tested for their capacity to adsorb a fluorescent miRNA. From our analysis, modification of surface charge with 0.1% APTMS ((3-Aminopropyl)trimethoxysilane) and 0.9% PEG-s (2-[Methoxy-(polyethyleneoxy)propyl]trimethoxysilane) performed at 60°C for 10min was identified as the best purification condition. Our optimized microdevice integrated with real-time PCR detection, was demonstrated to selectively purify both synthetic and natural circulating miRNAs with a sensitivity of 0.01pM.


Subject(s)
Biomarkers/blood , Dimethylpolysiloxanes/chemistry , MicroRNAs/isolation & purification , Microfluidic Analytical Techniques/methods , Fluorescent Dyes/chemistry , Humans , Isocyanates/chemistry , MicroRNAs/blood , MicroRNAs/chemistry , Microfluidic Analytical Techniques/instrumentation , Microscopy, Atomic Force , Photoelectron Spectroscopy , Real-Time Polymerase Chain Reaction , Silanes/chemistry , Surface Properties
3.
Nanotechnology ; 27(38): 385503, 2016 Sep 23.
Article in English | MEDLINE | ID: mdl-27532770

ABSTRACT

A new method, which is easily scalable to large scale production, has been developed to obtain gas sensor devices based on zinc oxide (ZnO) nanostructures with a 'tetrapod' shape. The method can be easily extended to other kinds of nanostructures and is based on the deposition of ZnO nanostructures through polymeric masks by centrifugation, directly onto properly designed MEMS micro-hotplates. The micromachined devices, after the mask is peeled off, are ready for electrical bonding and sensing test. Sensor response has been successfully measured for some gases and volatile organic compounds with different chemical properties (ethanol, methane, nitrogen dioxide, hydrogen sulfide).

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