Daniel Cohen recently escaped graduate school at UC Berkeley/UCSF (Bioengineering) with most of his fingers intact and a Ph.D. This still surprises him, especially as his doctoral work spanned inkjet printers, nanotube sensors, dinosaurs, Frankenstein, and swarming. He is now a post-doc at Stanford where he is applying his questionable skills to building cell-scale sheepdogs and electric bandages, and to making waterbears the new cupcake.
Daniel loves science outreach and is available for talks and demonstrations. He has participated in numerous panels, public lectures, and school workshops.
He is also available for consulting and can provide assistance with applications in mechanical, bio-, and materials engineering. Specialties in medical device design and lab automation tools. Services offered: microscopy (biological light/laser, SEM), soft lithography, microfluidics, rapid prototyping (CAD/CAM/CNC/3DP).
Honors & Awards
LSRF Research Fellow, Life Science Research Foundation (2014-2017)
NIH NRSA Fellowship Finalist (opted-out), NIH-NIBIB (2014)
NSF PRFB--Quantitative Biology Fellow (declined), NSF (2014)
NSF Graduate Research Fellow, NSF (2011-2013)
NDSEG Graduate Fellow, ASEE and DoD (2008-2011)
Boards, Advisory Committees, Professional Organizations
Advisory Board, Bay Area Arts and Science Interdisciplinary Collaborative Sessions (2014 - Present)
Fellow, Odd Salon (2016 - Present)
Advisor, DiAssess, Inc. (2014 - Present)
B.S.E., Princeton University, Mechanical Engineering (concentrations: materials science, engineering biology) (2008)
Doctor of Philosophy, University of California Berkeley (2013)
W James Nelson, Postdoctoral Faculty Sponsor
- Cell division orientation is coupled to cell-cell adhesion by the E-cadherin/LGN complex Nature Communications (in press) 2016
Epithelial self-healing is recapitulated by a 3D biomimetic E-cadherin junction
View details for DOI 10.1073/pnas.1612208113
- Galvanotactic control of collective cell migration in epithelial monolayers NATURE MATERIALS 2014; 13 (4): 409-417
A Highly Elastic, Capacitive Strain Gauge Based on Percolating Nanotube Networks
2012; 12 (4): 1821-1825
We present a highly elastic strain gauge based on capacitive sensing of parallel, carbon nanotube-based percolation electrodes separated by a dielectric elastomer. The fabrication, relying on vacuum filtration of single-walled carbon nanotubes and hydrophobic patterning of silicone, is both rapid and inexpensive. We demonstrate reliable, linear performance over thousands of cycles at up to 100% strain with less than 3% variability and the highest reported gauge factor for a device of this class (0.99). We further demonstrate use of this sensor in a robotics context to transduce joint angles.
View details for DOI 10.1021/nl204052z
View details for Web of Science ID 000302524600014
View details for PubMedID 22409332
Tail-assisted pitch control in lizards, robots and dinosaurs
2012; 481 (7380): 181-?
In 1969, a palaeontologist proposed that theropod dinosaurs used their tails as dynamic stabilizers during rapid or irregular movements, contributing to their depiction as active and agile predators. Since then the inertia of swinging appendages has been implicated in stabilizing human walking, aiding acrobatic manoeuvres by primates and rodents, and enabling cats to balance on branches. Recent studies on geckos suggest that active tail stabilization occurs during climbing, righting and gliding. By contrast, studies on the effect of lizard tail loss show evidence of a decrease, an increase or no change in performance. Application of a control-theoretic framework could advance our general understanding of inertial appendage use in locomotion. Here we report that lizards control the swing of their tails in a measured manner to redirect angular momentum from their bodies to their tails, stabilizing body attitude in the sagittal plane. We video-recorded Red-Headed Agama lizards (Agama agama) leaping towards a vertical surface by first vaulting onto an obstacle with variable traction to induce a range of perturbations in body angular momentum. To examine a known controlled tail response, we built a lizard-sized robot with an active tail that used sensory feedback to stabilize pitch as it drove off a ramp. Our dynamics model revealed that a body swinging its tail experienced less rotation than a body with a rigid tail, a passively compliant tail or no tail. To compare a range of tails, we calculated tail effectiveness as the amount of tailless body rotation a tail could stabilize. A model Velociraptor mongoliensis supported the initial tail stabilization hypothesis, showing as it did a greater tail effectiveness than the Agama lizards. Leaping lizards show that inertial control of body attitude can advance our understanding of appendage evolution and provide biological inspiration for the next generation of manoeuvrable search-and-rescue robots.
View details for DOI 10.1038/nature10710
View details for Web of Science ID 000298981200035
View details for PubMedID 22217942
- In-vivo study of adhesion and bone growth around implanted laser groove/RGD-functionalized Ti-6Al-4V pins in rabbit femurs MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 2011; 31 (5): 826-832
A Modified Consumer Inkjet for Spatiotemporal Control of Gene Expression
2009; 4 (9)
This paper presents a low-cost inkjet dosing system capable of continuous, two-dimensional spatiotemporal regulation of gene expression via delivery of diffusible regulators to a custom-mounted gel culture of E. coli. A consumer-grade, inkjet printer was adapted for chemical printing; E. coli cultures were grown on 750 microm thick agar embedded in micro-wells machined into commercial compact discs. Spatio-temporal regulation of the lac operon was demonstrated via the printing of patterns of lactose and glucose directly into the cultures; X-Gal blue patterns were used for visual feedback. We demonstrate how the bistable nature of the lac operon's feedback, when perturbed by patterning lactose (inducer) and glucose (inhibitor), can lead to coordination of cell expression patterns across a field in ways that mimic motifs seen in developmental biology. Examples of this include sharp boundaries and the generation of traveling waves of mRNA expression. To our knowledge, this is the first demonstration of reaction-diffusion effects in the well-studied lac operon. A finite element reaction-diffusion model of the lac operon is also presented which predicts pattern formation with good fidelity.
View details for DOI 10.1371/journal.pone.0007086
View details for Web of Science ID 000269970400014
View details for PubMedID 19763256