We present an automated droplet microfluidic system (DMF) to generate monitored nanoliter aqueous droplets in oil and their deposition on a commercial stainless steel plate for MALDI-TOF analysis of peptides or protein digests. We demonstrate that DMF-MALDI combination focuses the analyte on the MALDI plate, increasing considerably the homogeneity of the dried material. This results in a 30times enhanced MALDI-TOF MS signal for a model peptide, allowing a significant improvement of the detection sensitivity limit (down to few tens of attomoles). Moreover, positive detection can be achieved from sub-nanomolar peptides solutions and better overall protein sequence coverages are obtained from few tens attomoles of protein digest. These results make DMF-MALDI a promising approach for the treatment of peptides samples as well as a key component for an integrated approach in the proteomic field.
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http://dx.doi.org/10.1038/s41598-017-06660-8 | DOI Listing |
Anal Chem
October 2022
Department of Bioengineering, University of Washington, Seattle, Washington 98195, United States.
A picoliter thin-layer chromatography (pTLC) platform was developed for analyzing extremely miniature specimens, such as assay of the contents of a single cell of 1 picoliter volume. The pTLC chip consisted of an array of microscale bands made from highly porous monolithic silica designed to accept picoliter-scale volume samples. pTLC bands were fabricated by combining sol-gel chemistry and microfabrication technology.
View Article and Find Full Text PDFPhys Chem Chem Phys
May 2021
Institute of Organic Synthesis and Photoreactivity (ISOF) - (CNR), via Gobetti 101, 40129 Bologna, Italy. and Department of Industrial and Materials Science, Chalmers University of Technology, Hörsalvägen 7, 41296 Gothenburg, Sweden.
It is important, but challenging, to measure the (photo)induced switching of molecules in different chemical environments, from solution through thin layers to solid bulk crystals. We compare the cis-trans conformational switching of commercial azobenzene molecules in different liquid and solid environments: polar solutions, liquid polymers, 2D nanostructures and 3D crystals. We achieve this goal by using complementary techniques: optical absorption spectroscopy, femtosecond transient absorption spectroscopy, Kelvin probe force microscopy and reflectance spectroscopy, supported by density functional theory calculations.
View Article and Find Full Text PDFLuminescence
December 2020
Hitachi Ltd, Tokyo, Japan.
Analytical techniques using ATP bioluminescence, which has a high quantum yield and substrate specificity, are widely used in various assays, such as luciferase reporter assays, in the biological sciences. Although most microplate luminometers can be used to measure ATP luminescence with 96-well or 384-well microplates, their ATP detection limits are typically several tens of amol, which is not sufficient for evaluating cell activities and variability within small samples, such as those containing only a few cells. To analyze cell activities at low ATP concentrations, a more sensitive microplate luminometer is required.
View Article and Find Full Text PDFSci Rep
July 2017
LIONS, NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif sur Yvette Cedex, France.
We present an automated droplet microfluidic system (DMF) to generate monitored nanoliter aqueous droplets in oil and their deposition on a commercial stainless steel plate for MALDI-TOF analysis of peptides or protein digests. We demonstrate that DMF-MALDI combination focuses the analyte on the MALDI plate, increasing considerably the homogeneity of the dried material. This results in a 30times enhanced MALDI-TOF MS signal for a model peptide, allowing a significant improvement of the detection sensitivity limit (down to few tens of attomoles).
View Article and Find Full Text PDFAnal Chem
August 2014
C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States.
A new instrument that couples a low-pressure drift tube with a linear ion trap mass spectrometer is demonstrated for complex mixture analysis. The combination of the low-pressure separation with the ion trapping capabilities provides several benefits for complex mixture analysis. These include high sensitivity, unique ion fragmentation capabilities, and high reproducibility.
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