Materials Research Science and Engineering Center
Calendar of MRSEC Events
2018 Events
August 11, 2018 2018 Research Experiences for Undergraduates (REU)
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June 4, 2018 2018 Research Experiences for Undergraduates (REU)
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March 30, 2018 74th New England Complex Fluids Workshop at Yale University
February 28, 2018 Squishy Physics Seminar
Prof. Carlos Hidrovo, Mechanical and Industrial Engineering Department, Northeastern University

5:30pm | Pearce Hall, Room 209

Gas-Liquid Droplet Microfluidics: Fundamentals and Applications

Over the past two decades microfluidics has quickly morphed from an emerging field to a mature technology that is widely used in biotechnology and healthcare. One specific field that has thrived extensively in its adoption and development has been droplet microfluidics. The ability to compartmentalize reactions and processes into multiple individual droplets has made these systems extremely attractive in multiple and varied applications. However, most of the focus has centered on liquid-liquid systems, where dispersed droplets of a liquid are formed on another continuous, immiscible one.

This talk will focus on the relatively untapped field of gas-liquid droplet microfluidics, where liquid droplets are formed in a continuous, gaseous flow. The fundamentals of droplet formation and transport will be explored. Due to the lower viscosity of the carrier fluid, these systems tend to operate at much higher Re than those encountered in typical microfluidic systems. As such, the role of inertial forces on the dynamics of these systems will be addressed. Applications geared towards the creation of monodisperse aerosols and the sampling of gaseous targets will be discussed. A specific example on the sampling and detection of gaseous ammonia will be presented. The talk will finish with an outlook on the future of these systems.
February 21, 2018 Squishy Physics Seminar
Lisa Tran, Department of Physics, University of Pennsylvania

5:20pm | Pearce Hall, Room 209

A change in stripes for liquid crystal shells — controlling elasticity to order nanomaterials

Liquid crystals are ubiquitous in modern society. Whenever we text, use a calculator, or check our emails, we are interacting with LCDs — liquid crystal displays. These materials are the basis of the modern display industry because of their unique properties. They can be manipulated with electric fields and can alter light. They are also deformable because they are elastic: their rod-like molecules tend to align with one another. These properties allow for liquid crystals to be engineered into a pixel. Despite these advances in their technological applications so far, the structures that liquid crystals can form are yet to be completely understood. Current research aims to elucidate these structures to develop liquid crystals as biological sensors and as blue prints for assembling nanomaterials in energy applications.

Since liquid crystal molecules tend to order with one another, they can respond to geometrical confinement. Geometrical constraints can create patterned molecular structures and defects — localized, "melted" areas of disorder that can lower the distortion in the system and that can drive the assembly of objects. I will present recent work in which defects are controlled by using microfluidics to create liquid crystal double emulsion droplets — confining the liquid crystal into spherical shells. Molecular configurations are controlled by the topology and geometry of the system and by varying the concentration of surfactants. Defect structures are examined through experiments and simulations, and the surfactant concentration is altered to transition between different defect types. I will then present ongoing experiments where nanoparticles are used in place of traditional surfactants to pattern them at the liquid crystal-water interface. This work has the potential to dynamically template nanomaterials for the enhancement of liquid crystal-based optical devices and sensors.
February 14, 2018 Squishy Physics Seminar
Prof. Thomas C. Pochapsky, Department of Chemistry, Brandeis University

5:20pm | Pearce Hall, Room 209

Some surprising implications of NMR-directed simulations of substrate recognition and binding by cytochromes P450

Cytochromes P450 are a superfamily of heme-containing monooxygenases that typically catalyze the oxidation of unactivated C-H and C=C bonds by molecular oxygen, often with high regio- and stereospecificity. Over 450,000 members of the superfamily have been tentatively identified, from all genera of life, suggesting a vast range of possible substrates and even larger one of potential products. However, little is yet known about the relationship between sequence, structure and substrate/product specificity in P450s. Residual dipolar couplings (RDCs) measured for backbone amide 1H-15N correlations in substrate-free and bound forms of two P450s, the camphor 5-exo hydroxylase CYP101A1 and macrolide antibiotic biosynthetic MycG were used as restraints in soft annealing molecular dynamics (MD) simulations in order to identify average conformations of these enzymes with and without substrate bound. Multiple substrate-dependent conformational changes remote from the enzyme active site were identified in both enzymes. Perturbation response scanning (PRS) and umbrella sampling MD of the RDC-derived CYP101A1 structures are used to probe the roles of remote structural features in enforcing the regio- and stereospecific nature of the hydroxylation reaction catalyzed by CYP101A1. An improper dihedral angle Ψ was used to maintain substrate orientation in the CYP101A1 active site, and it different values of Ψ result in different PRS response maps. Umbrella sampling methods show that the free energy of the system is sensitive to Ψ, and bound substrate forms an important mechanical link in the transmission of mechanical coupling through the enzyme structure. Finally, a qualitative approach to interpreting PRS maps in terms of the roles of secondary structural features is proposed.
February 7, 2018 Squishy Physics Seminar
Prof. Yujun Song, Department of Physics, University of Science and Technology Beijing

5:20pm | Pearce Hall, Room 301

Microfluidic Synthesis of Nanomaterials and their Application for Tumor Diagnosis and Therapy

Great progresses in the coupling of nanomaterials and biomedicines have been achieved in the disease diagnosis and therapy, leading to the brand-new field in nanomedicines by conjugating nanoparticles with bio-molecules in the past decades. However, the controlled synthesis of varieties of nanoparticles and their surface modification and conjugation with desired medicines (particularly small organics with inorganic nanoparticles) are still much challenging. Here we developed a programmed microfluidic process in the controlled synthesis of varieties of hybrid nanoparticles and versatile surface modification and functionalization processes based on comprehensive coupling reactions, fulfilling these issues. Thus, surfaces of noble metal, metal@metal-oxide or ceramic nanoparticles can be conveniently modified and conjugated with biomolecules with –NHx, -COOH or –OH ligands. Using breast cancer and hepatocellular carcinoma as disease model, and noble metal and magnetic-metal@metal-oxide as nanoparticle model, several nanomedicines have been successfully synthesized based on the invented conjugation process. Their applications as molecule imaging enhancers (MRI or CT), targeting nanoprobes and anti-tumor nanomedicines were evaluated, showing excellent clinical potentials.
February 1, 2018 2018 Research Experiences for Undergraduates (REU)
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2017 Events
December 13, 2017 Squishy Physics Seminar
Prof. Jeff Gelles, Department of Biochemistry, Brandeis University

5:20pm | Pearce Hall, Room 209

Non-equilibrium control of DNA transcription

Cells in all forms of life regulate the actions of their genes by controlling the production of messenger RNAs. The regulatory molecular machinery is complex, often involving a dozen or more different proteins that may interact with each other, with RNA polymerase, with template DNA and with nascent RNA. I'll discuss projects in which we used in vitro multi-wavelength single-molecule fluorescence approaches to elucidate dynamic mechanisms by which bacterial transcript elongation is regulated. The studies show that quasi-equilibrium models are not adequate to explain these regulatory processes — they are kinetically controlled — and they reveal unexpected features of regulation, including a new transcription cycle for bacterial RNA polymerase.
December 10, 2017 Holiday Lecture Series

Hold Your Temper: Celebrating the Science of Chocolate

11:00am - 12:00pm, and 2:00pm - 3:00pm sessions | Science Center Lecture Hall B
Where does chocolate come from? Why does some chocolate melt in your mouth but not in your hand? What makes a chocolate bar smooth and creamy?
December 1, 2017 73rd New England Complex Fluids Workshop at Harvard University
September 22, 2017 72nd New England Complex Fluids Workshop at Brandeis University
June 16, 2017 71st New England Complex Fluids Workshop at Tufts University
March 24, 2017 70th New England Complex Fluids Workshop at Brandeis University
2016 Events
November 30, 2016 69th New England Complex Fluids Workshop at Harvard University
September 21, 2016 68th New England Complex Fluids Workshop at Brandeis University
June 6, 2016 67th New England Complex Fluids Workshop at Tufts University
March 23, 2016 66th New England Complex Fluids Workshop at Brandeis University
2015 Events
February 28, 2015 Research Experience for Undergraduates (REU) Program, applications and transcripts due.
December 4, 2015 65th New England Complex Fluids Workshop at Harvard University
September 18, 2015 64th New England Complex Fluids Workshop at Brandeis University
June 5, 2015 63rd New England Complex Fluids Workshop at Tufts University
March 20, 2015 62nd New England Complex Fluids Workshop at Brandeis University

Prior Events