个人简介

B.S., 1989, Brigham Young Univ. M.S., 1990, Brigham Young Univ. Ph.D., 1995, The Weizmann Institute of Science NIH Postdoctoral Fellow, 1995-1997, Texas A&M Univ. AwardOrganizationDivisionLevel CodeType CodeStart DateEnd Date Teacher-Scholar AwardMichigan State UniversityCollege of Natural ScienceProfessionalHonors2003 Junior Faculty AwardSigma Xi Honor SocietyMichigan State UniversityProfessionalHonors2002 Young Investigator AwardSociety for Electroanalytical ChemistryProfessionalHonors2000 Ph.D.The Weizmann Institute of Science, Rehovot, IsraelGraduateDegree1995 NIH Postdoctoral FellowTexas A&M UniversityPostdoctoralFellowship19951997 M.S.Brigham Young University, Provo, UTGraduateDegree1990 Bachelor of Science Magna Cum LaudeBrigham Young University, Provo, UTUndergraduateDegree1989

研究领域

Analytical Biological Materials

(Research Description PDF - 1714 kb) Alternating adsorption of polyanions and poly-cations creates an ultrathin skin on a porous alumina support (top). The skin allows selective removal of multivalent ions for water softening (bottom). Because the skin is ultrathin, the separation can occur at low pressure. Functional polymer films are attractive for applications in catalysis, water treatment, and protein purification, and our research focuses on polymer adsorption or growth of polymers from surfaces to create functional coatings for these applications. One area of this work involves alternating adsorption of polycations and polyanions to form ultrathin separation membranes on highly porous supports. Judicious selection of the constituent polyelectrolytes in these films affords membranes that are selectively permeable to specific ions and small neutral molecules such as sugars. Target applications include water softening and salt purification, and the ultrathin films allow these separations to occur at low pressures and reduce energy costs. Current research focuses on the combination of electrical potentials and ultrathin films to enhance ion separations and better understand desalination. In a second area, we grow polymer brushes and swollen polyelectrolyte films in the pores of membranes. When derivatized with metal-ion complexes, these coatings selectively bind multilayers of polyhistidine-tagged proteins to facilitate protein purification. The films greatly increase protein binding capacity, and the small pores in the membranes reduce diffusion distances to allow rapid protein adsorption. Purification with such membranes can occur in a few minutes, and this is especially attractive for isolating therapeutic proteins. SEM image of a porous membrane coated with catalytically active gold nanoparticles. The final focus of our research is synthesis of films or membranes containing catalytic enzymes. Layer-by-layer adsorption of polyanions and positively charged enzymes creates membranes that rapidly digest proteins prior to their analysis by mass spectrometry. Variation of the flow rate through an enzyme-containing membrane controls the size of the resulting proteolytic peptides, with larger peptides appearing at high flow rates due to limited digestion. Large peptides are particularly attractive for obtaining high sequence coverages in the study of posttranslational protein modifications such as phosphorylation, which regulates many cell processes. Additionally, limited digestion can provide information on protein structure by demonstrating which regions of a protein are most accessible to an enzyme. All of these projects require thorough surface characterization. To investigate ultrathin films and their properties, we employ atomic force microscopy, field-emission scanning electron microscopy, ellipsometry, electrochemical techniques, grazing angle reflectance infrared spectroscopy, X-ray photoelectron spectroscopy, contact-angle measurements, and permeation experiments. Rapid flow of proteins through enzyme-containing membranes leads to missed cleavage sites and produces large peptides that are attractive for analysis by mass spectrometry. All of these projects require thorough surface characterization. To investigate ultrathin films and their properties, we employ atomic force microscopy, field-emission scanning electron microscopy, ellipsometry, electrochemical techniques, grazing angle reflectance infrared spectroscopy, X-ray photoelectron spectroscopy, contact-angle measurements, and permeation experiments.

近期论文

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C. Sheng, S. Wijeratne, C. Cheng, G.L. Baker, and M.L. Bruening, "Facilitated Ion Transport Through Polyelectrolyte Multilayer Films Containing Metal-Binding Ligands" J. Membrane Sci. 459, 169-176 (2014). C. Cheng, N. White, H. Shi, M. Robson, and M.L. Bruening, "Cation Separations in Electrodialysis through Membranes Coated with Polyelectrolyte Multilayers" Polymer 55, 1397-1403 (2014). S. Wijeratne, M.L. Bruening, and G.L. Baker, "Layer-by-Layer Assembly of Thick, Cu2+-Chelating Films" Langmuir, 29, 12720-12729 (2013). J.A. Armstrong, E.E.L. Bernal, A. Yaroshchuk, and M.L. Bruening, "Separation of Ions Using Polyelectrolyte-Modified Nanoporous Track-Etched Membranes" Langmuir 29, 10287-10296 (2013). A. Yaroshchuk, M.L Bruening, and E.E.L. Bernal, "Solution-Diffusion-Migration Model and its Uses for Analysis of Nanofiltration, Pressure-Retarded Osmosis and Forward Osmosis in Multi-ionic Solutions" J. Membrane Sci.447, 463-476 (2013). Y.-J. Tan, D. Sui, W-H. Wang, M.-H. Kuo, G. E. Reid, and M.L. Bruening, "Phosphopeptide Enrichment with TiO2-Modified Membranes and Investigation of Tau Protein Phosphorylation" Anal. Chem. 85, 5699-5706 (2013). Y. Ma, J. Dong, S. Bhattacharjee, S. Wijeratne, M.L. Bruening, and G. L. Baker, "Increased Protein Sorption in Poly(acrylic acid)-Containing Films Through Incorporation of Comb-like Polymers and Film Adsorption at Low pH and High Ionic Strength" Langmuir, 29, 1946-2954 (2013). C. Cheng, A. Yaroshchuk, and M.L. Bruening, "Fundamentals of Selective Ion Transport through Multilayer Polyelectrolyte Membranes" Langmuir, 29, 1885-1892 (2013). S. Saha, M.L. Bruening, and G.L. Baker, "Surface-Initiated Polymerization of Azidopropyl Methacrylate and Its Film Elaboration via Click Chemistry" Macromolecules 45, 9063-9069 (2012). Y.-J. Tan, W.-H. Wang, Y. Zheng, J. Dong, G. Stefano, F. Brandizzi, R.M. Garavito, G.E. Reid, and M.L. Bruening, "Limited Proteolysis via Millisecond Digestions in Protease-Modified Membranes" Anal. Chem. 84, 8357–8363 (2012). S. Bhattacharjee, J. Dong, Y. Ma, S. Hovde, J.H. Geiger, G.L. Baker, and M.L. Bruening, "Formation of High-Capacity Protein-Adsorbing Membranes through Simple Adsorption of Poly(acrylic acid)-Containing Films at Low pH" Langmuir 28, 6885–6892 (2012). S.R. Hogg, S. Muthu, M. O’Callaghan, J.-F. Lahitte, and M.L. Bruening, "Wet-Air Oxidation of Formic Acid Using Nanoparticle-Modified Polysulfone Hollow Fibers as Gas-Liquid Contactors" ACS Appl. Mater. Interfaces 4, 1440-1448 (2012). N. Anuraj, S. Bhattacharjee, J.H. Geiger, G.L. Baker, and M.L. Bruening "An All-aqueous Route to Polymer Brush-modified Membranes with Remarkable Permeabilites and Protein Capture Rates" J. Membrane Sci. 389, 117-125 (2012). S. Saha, M.L. Bruening, and G.L. Baker, "Facile Synthesis of Thick Films of Poly(methyl methacrylate), Poly(styrene), and Poly(vinyl pyridine) from Au Surfaces" ACS Appl. Mat. & Interfaces 3, 3042-3048 (2011). W-H. Wang, J.-L. Dong, G.L. Baker, and M.L. Bruening, "Bifunctional Polymer Brushes for Low-bias Enrichment of Mono- and Multi-phosphorylated Peptides" Analyst 136, 3595-3598 (2011). F. Xu, J.H. Geiger, G.L. Baker, and M.L. Bruening, "Polymer Brush-Modified Magnetic Nanoparticles for His-Tagged Protein Purification" Langmuir 27, 3106-3112 (2011). F. Xu, W.-H. Wang, Y.-J. Tan, and M.L. Bruening, "Facile Trypsin Immobilization in Polymeric Membranes for Rapid, Efficient Protein Digestion" Anal. Chem. 82, 10045-10051 (2010). Y. Zheng, M.L. Bruening, and G.L. Baker, "Crystallization Kinetics of Polymer Brushes with Poly(ethylene oxide) Side Chains" J. Polymer Sci. B. Polymer Phys. 48, 1955-1959 (2010). S.T. Grajales, X. Dong, Y. Zheng, G.L. Baker, and M.L. Bruening, "Effects of Monomer Composition on CO2-Selective Polymer Brush Membranes" Chem. Mater. 22, 4026–4033 (2010). W.-H. Wang, A.M. Palumbo, Y.-J. Tan, G.E. Reid, J.J. Tepe, and M.L. Bruening, "Identification of p65-associated Phosphoproteins by Mass Spectrometry after On-plate Phosphopeptide Enrichment Using Polymer-oxotitanium Films" J. Proteome Res. 9, 3005–3015 (2010).