Engineering topics
Mai, Junyu
Publications and source records attributed to Mai, Junyu.
Functionalized Polyacrylamide Monolith for Rapid Bacteria Pathogen Detection in Human Blood.
Abstract not provided.
Selective Field-Biased Gating of Biopolymers at Confining Nanopores.
Abstract not provided.
Spatiotemporal Mapping of Concentration Polarization Induced pH Changes at Nanoconstrictions
Under an applied electric field, concentration polarization (CP) arises from ion permselectivity of most nanoporous materials and biological ion channels. We present novel methods to quantitatively assess CP-induced spatiotemporal changes of pH that may significantly impact transport dynamics, device functionality, and physicochemical properties of molecular analytes in devices with nanofluidic constrictions. We measured pH fluctuations of >1.5 pH units and changes extending over 100's of micrometers from nanoconstrictions. The degree of change depends on key system parameters including buffer composition, surface charge, and strength of electric field. The results highlight the importance of neglected contributions of pH changes, and the approach can aid characterization and manipulation of mass transport in nanofluidic systems.
Microfluidic Digital Isoelectric Fractionation for Rapid Multi-dimensional Glycoprotein Analysis.
Abstract not provided.
Biotechnology development for biomedical applications.
Sandia's scientific and engineering expertise in the fields of computational biology, high-performance prosthetic limbs, biodetection, and bioinformatics has been applied to specific problems at the forefront of cancer research. Molecular modeling was employed to design stable mutations of the enzyme L-asparaginase with improved selectivity for asparagine over other amino acids with the potential for improved cancer chemotherapy. New electrospun polymer composites with improved electrical conductivity and mechanical compliance have been demonstrated with the promise of direct interfacing between the peripheral nervous system and the control electronics of advanced prosthetics. The capture of rare circulating tumor cells has been demonstrated on a microfluidic chip produced with a versatile fabrication processes capable of integration with existing lab-on-a-chip and biosensor technology. And software tools have been developed to increase the calculation speed of clustered heat maps for the display of relationships in large arrays of protein data. All these projects were carried out in collaboration with researchers at the University of Texas M. D. Anderson Cancer Center in Houston, TX.
Microscale isoelectric fractionation using immobilized pH-specific membranes for multi-dimensional analysis.
We report on advancements of our microscale isoelectric fractionation ({mu}IEFr) methodology for fast on-chip separation and concentration of proteins based on their isoelectric points (pI). We establish that proteins can be fractionated depending on posttranslational modifications into different pH specific bins, from where they can be efficiently transferred to downstream membranes for additional processing and analysis. This technology can enable on-chip multidimensional glycoproteomics analysis, as a new approach to expedite biomarker identification and verification.
Microscale isoelectric fractionation using immobilized pH-specific membranes for multi-dimensional analysis.
Abstract Not Provided