Danielle J. Mai joined the Department of Chemical Engineering at Stanford in January 2020. She earned her B.S.E. in Chemical Engineering from the University of Michigan and her M.S. and Ph.D. in Chemical Engineering from the University of Illinois at Urbana-Champaign under the guidance of Prof. Charles M. Schroeder. Danielle was an Arnold O. Beckman Postdoctoral Fellow in Prof. Bradley D. Olsen's group at MIT, where she engineered materials with selective biomolecular transport properties, elucidated mechanisms of toughness and extensibility in entangled associative hydrogels, and developed high-throughput methods for the discovery of polypeptide materials. The Mai Research Group integrates precise biopolymer engineering with multiscale experimental characterization to advance biomaterials development and to enhance fundamental understanding of soft matter physics.
Honors & Awards
AIChE 35 Under 35, American Institute of Chemical Engineers (2020)
1st Place Poster Prize, Division of Polymer Physics, American Physical Society (2018)
Future Faculty Scholar, Polymeric Materials Science and Engineering, American Chemical Society (2018)
MIT IMPACT Fellow, Massachusetts Institute of Technology (2018)
Arnold O. Beckman Postdoctoral Fellowship, Arnold and Mabel Beckman Foundation (2017)
Outstanding Graduate Student Award, Lam Research Corporation (2015)
NSF Graduate Research Fellowship, National Science Foundation (2013)
Illinois Distinguished Fellowship, University of Illinois (2011)
Boards, Advisory Committees, Professional Organizations
Chair, Polymer Physics Gordon Research Seminar (2016 - 2018)
Postdoc, Massachusetts Institute of Technology, Chemical Engineering
PhD, University of Illinois, Chemical Engineering (2016)
MS, University of Illinois, Chemical Engineering (2014)
BSE, University of Michigan, Chemical Engineering (2011)
- Fundamentals and Applications of Spectroscopy
CHEMENG 345 (Win)
- Graduate Practical Training
CHEMENG 299 (Sum)
- Introduction to Chemical Engineering Thermodynamics
CHEMENG 110A (Aut)
Independent Studies (5)
- Graduate Research Rotation in Chemical Engineering
CHEMENG 399 (Aut, Win, Sum)
- Graduate Research in Chemical Engineering
CHEMENG 600 (Aut, Win, Spr, Sum)
- Ph.D. Research
MATSCI 300 (Aut, Win)
- Undergraduate Honors Research in Chemical Engineering
CHEMENG 190H (Aut, Win, Spr, Sum)
- Undergraduate Research in Chemical Engineering
CHEMENG 190 (Aut, Win, Spr, Sum)
- Graduate Research Rotation in Chemical Engineering
- Prior Year Courses
Doctoral Dissertation Advisor (AC)
Tuning Selective Transport of Biomolecules through Site-Mutated Nucleoporin-like Protein (NLP) Hydrogels.
Natural selective filtering systems (e.g., the extracellular matrix, nuclear pores, and mucus) separate molecules selectively and efficiently, and the detailed understanding of transport mechanisms exploited in these systems provides important bioinspired design principles for selective filters. In particular, nucleoporins consist of consensus repeat sequences that are readily utilized for engineering repeat proteins. Here, the consensus repeat sequence of Nsp1, a yeast nucleoporin, is polymerized to form a nucleoporin-like protein (NLP) and mutated to understand the effect of sequence on selective transport. The hydrophilic spacers of the NLPs were redesigned considering net charge, charge distribution, and polarity. Mutations were made near to and far from the FSFG interacting domain to explore the role of highly conserved residues as a function of spatial proximity. A nuclear transport receptor-cargo complex, nuclear transport factor 2-green fluorescent protein (NTF2-GFP), was used as a model for changes in transport. For mutations of the charged spacer, some mutations of highly conserved charged residues were possible without knocking out selective transport of the NTF2, but the formation of regions of clustered negative charge has an unfavorable effect on nuclear transporter permeation. Thus, positive net charge and alternating positive and negative charge within the hydrophilic spacer are advantageous for recognition and selective transport. In the polarity panel, mutations that increased the interaction between NTF2-GFP and the gel led to decreased permeation of the NTF2-GFP due to blocking of the interface and inability of the NTF2-GFP to transport into the gel. Therefore, these results provide a strategy for tuning selective permeability of biomolecules using the artificially designed consensus repeat-based hydrogels.
View details for DOI 10.1021/acs.biomac.0c01083
View details for PubMedID 33428378
- 100th Anniversary of Macromolecular Science Viewpoint: Single-Molecule Studies of Synthetic Polymers ACS MACRO LETTERS 2020; 9 (9): 1332–41
- Molecular anisotropy and rearrangement as mechanisms of toughness and extensibility in entangled physical gels PHYSICAL REVIEW MATERIALS 2020; 4 (1)
Glycoprotein Mimics with Tunable Functionalization through Global Amino Acid Substitution and Copper Click Chemistry.
Glycoproteins and their mimics are challenging to produce because of their large number of polysaccharide side chains that form a densely grafted protein-polysaccharide brush architecture. Herein a new approach to protein bioconjugate synthesis is demonstrated that can approach the functionalization densities of natural glycoproteins through oligosaccharide grafting. Global amino acid substitution is used to replace the methionine residues in a methionine-enriched elastin-like polypeptide with homopropargylglycine (HPG); the substitution was found to replace 93% of the 41 methionines in the protein sequence as well as broaden and increase the thermoresponsive transition. A series of saccharides were conjugated to the recombinant protein backbones through copper(I)-catalyzed alkyne-azide cycloaddition to determine reactivity trends, with 83-100% glycosylation of HPGs. Only an acetyl-protected sialyllactose moiety showed a lower level of 42% HPG glycosylation that is attributed to steric hindrance. The recombinant glycoproteins reproduced the key biofunctional properties of their natural counterparts such as viral inhibition and lectin binding.
View details for DOI 10.1021/acs.bioconjchem.9b00601
View details for PubMedID 32078297
- Stretching Dynamics of Single Comb Polymers in Extensional Flow MACROMOLECULES 2018; 51 (4): 1507–17
Nucleopore-Inspired Polymer Hydrogels for Selective Biomolecular Transport.
2018; 19 (10): 3905–16
Biological systems routinely regulate biomolecular transport with remarkable specificity, low energy input, and simple mechanisms. Here, the biophysical mechanisms of nuclear transport inspire the development of gels for recognition and selective permeation (GRASP). GRASP presents a new paradigm for specific transport and selective permeability, in which binding interactions between a biomolecule and a hydrogel lead to faster penetration of the gel. A molecular transport theory identifies key principles for selective transport: entropic repulsion of noninteracting molecules and affinity-mediated diffusion of multireceptor biomolecules through a walking mechanism. The ability of interacting molecules to walk through hydrogels enables enhanced permeability in polymer networks. To realize this theoretical prediction in a novel material, GRASP is engineered from a poly(ethylene glycol) network (entropic barrier) containing antibody-binding oligopeptides (affinity domains). GRASP is synthesized using simultaneous bioconjugation and polycondensation reactions. The elastic modulus, characteristic pore size, biomolecular diffusivity, and selective permeability are measured in the resulting materials, which are applied to regulate the transport of equally sized molecules by preferentially transporting a monoclonal antibody from a polyclonal mixture. Overall, this work presents rationally designed, nucleopore-inspired hydrogels that are capable of controlling biomolecular transport.
View details for DOI 10.1021/acs.biomac.8b00556
View details for PubMedID 30183264
- Single polymer dynamics of topologically complex DNA CURRENT OPINION IN COLLOID & INTERFACE SCIENCE 2016; 26: 28–40
- Topology-Controlled Relaxation Dynamics of Single Branched Polymers ACS Macro Letters 2015; 4 (4): 446–52
- Template-Directed Synthesis of Structurally Defined Branched Polymers MACROMOLECULES 2015; 48 (5): 1296–1303
Microfluidic systems for single DNA dynamics
2012; 8 (41): 10560–72
Recent advances in microfluidics have enabled the molecular-level study of polymer dynamics using single DNA chains. Single polymer studies based on fluorescence microscopy allow for the direct observation of non-equilibrium polymer conformations and dynamical phenomena such as diffusion, relaxation, and molecular stretching pathways in flow. Microfluidic devices have enabled the precise control of model flow fields to study the non-equilibrium dynamics of soft materials, with device geometries including curved channels, cross-slots, and microfabricated obstacles and structures. This review explores recent microfluidic systems that have advanced the study of single polymer dynamics, while identifying new directions in the field that will further elucidate the relationship between polymer microstructure and bulk rheological properties.
View details for DOI 10.1039/c2sm26036k
View details for Web of Science ID 000310829300005
View details for PubMedID 23139700
View details for PubMedCentralID PMC3489478
Influence of Polyethyleneimine Graftings of Multi-Walled Carbon Nanotubes on their Accumulation and Elimination by and Toxicity to Daphnia magna
ENVIRONMENTAL SCIENCE & TECHNOLOGY
2011; 45 (3): 1133–38
Modifications of carbon nanotubes (CNTs) for different applications may change their physicochemical properties such as surface charge. Assessments of the extent to which such modifications influence CNT ecotoxicity, accumulation, and elimination behaviors are needed to understand potential environmental risks these variously modified nanoparticles may pose. We have modified carbon-14 labeled multi-walled carbon nanotubes (MWNTs) with polyethyleneimine (PEI) surface coatings to increase their aqueous stability and to give them positive, negative, or neutral surface charges. Uptake and elimination behaviors of Daphnia magna exposed to PEI-coated and acid-modified MWNTs at concentrations of approximately 25 and 250 μg/L were quantified. PEI surface coatings did not appear to substantially impact nanotube accumulation or elimination rates. Although the PEI-modified nanotubes exhibited enhanced stability in aqueous solutions, they appeared to aggregate in the guts of D. magna in a manner similar to acid-treated nanotubes. The MWNTs were almost entirely eliminated by Daphnia fed algae during a 48 h elimination experiment, whereas elimination without feeding was typically minimal. Finally, PEI coatings increased MWNT toxicities, though this trend corresponded to the size of the PEI coatings, not their surface charges.
View details for DOI 10.1021/es1030239
View details for Web of Science ID 000286577100045
View details for PubMedID 21182278
Response of Sinorhizobium meliloti to elevated concentrations of cadmium and zinc
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
2008; 74 (13): 4218–21
Whole-genome transcriptional profiling was used to identify genes in Sinorhizobium meliloti 1021 that are differentially expressed during exposure to elevated concentrations of cadmium and zinc. Mutant strains with insertions in metal-regulated genes and in genes encoding putative metal efflux pumps were analyzed for their metal sensitivities, revealing a crucial role for the SMc04128-encoded P-type ATPase in the defense of S. meliloti against cadmium and zinc stress.
View details for DOI 10.1128/AEM.02244-07
View details for Web of Science ID 000257446900032
View details for PubMedID 18469129
View details for PubMedCentralID PMC2446505