Professional Education


  • Doctor of Philosophy, Columbia University (2016)
  • Master of Science, Columbia University, Biomedical Engineering (2012)
  • Bachelor of Science, California Institute of Technology (2010)

Stanford Advisors


All Publications


  • Biophysics of Collective Phototaxis of Euglena gracilis Tsang, A. H., Lam, A. T., Riedel-Kruse, I. H. CELL PRESS. 2018: 650A
  • Versatile Phototactic Behaviors of the Chiral Microswimmer Euglena gracilis Tsang, A., Lam, A., Riedel-Kruse, I. H. CELL PRESS. 2018: 653A
  • Reversibly Bound Kinesin-1 Motor Proteins Propelling Microtubules Demonstrate Dynamic Recruitment of Active Building Blocks NANO LETTERS Lam, A., Tsitkov, S., Zhang, Y., Hess, H. 2018; 18 (2): 1530–34

    Abstract

    Biological materials and systems often dynamically self-assemble and disassemble, forming temporary structures as needed and allowing for dynamic responses to stimuli and changing environmental conditions. However, this dynamic interplay of localized component recruitment and release has been difficult to achieve in artificial molecular-scale systems, which are usually designed to have long-lasting, stable bonds. Here, we report the experimental realization of a molecular-scale system that dynamically assembles and disassembles its building blocks while retaining functionality. In our system, filaments (microtubules) recruit biomolecular motors (kinesins) to a surface engineered to allow for the reversible binding of the kinesin-1 motors. These recruited motors work to propel the cytoskeletal filaments along the surface. After the microtubules leave the motors behind, the trail of motors disassembles, releasing the motors back into solution. Engineering such dynamic systems may allow us to create materials that mimic the way in which biological systems achieve self-healing and adaptation.

    View details for DOI 10.1021/acs.nanolett.7b05361

    View details for Web of Science ID 000425559700126

    View details for PubMedID 29318877

  • Device and programming abstractions for spatiotemporal control of active micro-particle swarms LAB ON A CHIP Lam, A. T., Samuel-Gama, K. G., Griffin, J., Loeun, M., Gerber, L. C., Hossain, Z., Cira, N. J., Lee, S. A., Riedel-Kruse, I. H. 2017; 17 (8): 1442-1451

    Abstract

    We present a hardware setup and a set of executable commands for spatiotemporal programming and interactive control of a swarm of self-propelled microscopic agents inside a microfluidic chip. In particular, local and global spatiotemporal light stimuli are used to direct the motion of ensembles of Euglena gracilis, a unicellular phototactic organism. We develop three levels of programming abstractions (stimulus space, swarm space, and system space) to create a scripting language for directing swarms. We then implement a multi-level proof-of-concept biotic game using these commands to demonstrate their utility. These device and programming concepts will enhance our capabilities for manipulating natural and synthetic swarms, with future applications for on-chip processing, diagnostics, education, and research on collective behaviors.

    View details for DOI 10.1039/c7lc00131b

    View details for Web of Science ID 000399213700006

    View details for PubMedID 28322404

  • Cytoskeletal motor-driven active self-assembly in in vitro systems SOFT MATTER Lam, A. T., VanDelinder, V., Kabir, A. R., Hess, H., Bachand, G. D., Kakugo, A. 2016; 12 (4): 988–97

    Abstract

    Molecular motor-driven self-assembly has been an active area of soft matter research for the past decade. Because molecular motors transform chemical energy into mechanical work, systems which employ molecular motors to drive self-assembly processes are able to overcome kinetic and thermodynamic limits on assembly time, size, complexity, and structure. Here, we review the progress in elucidating and demonstrating the rules and capabilities of motor-driven active self-assembly. We focus on the types of structures created and the degree of control realized over these structures, and discuss the next steps necessary to achieve the full potential of this assembly mode which complements robotic manipulation and passive self-assembly.

    View details for DOI 10.1039/c5sm02042e

    View details for Web of Science ID 000369747900001

    View details for PubMedID 26576824

  • Controlling self-assembly of microtubule spools via kinesin motor density SOFT MATTER Lam, A. T., Curschellas, C., Krovvidi, D., Hess, H. 2014; 10 (43): 8731–36

    Abstract

    Active self-assembly, in which non-thermal energy is consumed by the system to put together building blocks, allows the creation of non-equilibrium structures and active materials. Microtubule spools assembled in gliding assays are one example of such non-equilibrium structures, capable of storing bending energies on the order of 10(5) kT. Although these structures arise spontaneously in experiments, the origin of microtubule spooling has long been debated. Here, using a stepwise kinesin gradient, we demonstrate that spool assembly can be controlled by the surface density of kinesin motors, showing that pinning of microtubules due to dead motors plays a dominant role in spool initiation.

    View details for DOI 10.1039/c4sm01518e

    View details for Web of Science ID 000343992100016

    View details for PubMedID 25269076

    View details for PubMedCentralID PMC4198420

  • Modeling Negative Cooperativity in Streptavidin Adsorption onto Biotinylated Microtubules LANGMUIR He, S., Lam, A. T., Jeune-Smith, Y., Hess, H. 2012; 28 (29): 10635–39

    Abstract

    The nanoscale architecture of binding sites can result in complex binding kinetics. Here, the adsorption of streptavidin and neutravidin to biotinylated microtubules is found to exhibit negative cooperativity due to electrostatic interactions and steric hindrance. This behavior is modeled by a newly developed kinetic analogue of the Fowler-Guggenheim adsorption model. The complex adsorption kinetics of streptavidin to biotinylated structures needs to be considered when these intermolecular bonds are employed in self-assembly and nanobiotechnology.

    View details for DOI 10.1021/la302034h

    View details for Web of Science ID 000306674000002

    View details for PubMedID 22765377

  • Nanoscale Transport Enables Active Self-Assembly of Millimeter-Scale Wires NANO LETTERS Idan, O., Lam, A., Kamcev, J., Gonzales, J., Agarwal, A., Hess, H. 2012; 12 (1): 240–45

    Abstract

    Active self-assembly processes exploit an energy source to accelerate the movement of building blocks and intermediate structures and modify their interactions. A model system is the assembly of biotinylated microtubules partially coated with streptavidin into linear bundles as they glide on a surface coated with kinesin motor proteins. By tuning the assembly conditions, microtubule bundles with near millimeter length are created, demonstrating that active self-assembly is beneficial if components are too large for diffusive self-assembly but too small for robotic assembly.

    View details for DOI 10.1021/nl203450h

    View details for Web of Science ID 000298943100042

    View details for PubMedID 22111572