Bio


We are a curiosity driven research group working in the field of physical biology. Our approach brings together experimental and theoretical techniques from soft-condensed matter physics, fluid dynamics, theory of computation and unconventional micro and nano-fabrication to open problems in biology: from organismal to cellular and molecular scale. We design and build precision instrumentation including droplet microfluidic tools to probe and perturb biological machines and their synthetic analogues. Along the way, we invent novel technologies in global health context with clinical applications in extreme resource poor settings.

Academic Appointments


Honors & Awards


  • MIT Ideas Sustainability Prize, MIT (2003)
  • Lemelson MIT Student Finalist Award, Lemelson Foundation (2008)
  • Junior Fellow (Physics), Harvard Society of Fellows (2008-2011)
  • TED Senior Fellow, Technology, Entertainment and Design (TED) (2011-2013)
  • Frederick E. Terman Fellow, Stanford University (2011-2013)
  • Pew Scholar, Pew Foundation (2013-2017)
  • TR35, MIT Technology Review (2014)
  • Brilliant 10, Popular Science Brilliant 10 (2014)

Professional Education


  • Ph.D., Massachusetts Institute of Technology, Field of Study: Applied Physics (MAS) (2008)
  • M.S., Massachusetts Institute of Technology, Field of Study: Applied Physics (MAS) (2004)
  • B.Tech, Indian Institute of Technology, Field of Study: Computer Science and Engineering (2002)

Community and International Work


  • Foldscope, India

    Topic

    Low-cost scientific instruments

    Partnering Organization(s)

    India Dept of Biotechnology

    Populations Served

    All

    Location

    International

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    No

  • Low-cost scanning of oral cavity, Kenya and India

    Topic

    oral cancer

    Location

    International

    Ongoing Project

    Yes

    Opportunities for Student Involvement

    Yes

2015-16 Courses


Stanford Advisees


Graduate and Fellowship Programs


All Publications


  • Wetting: Bumps lead the way. Nature materials Prakash, M. 2016; 15 (4): 378-379

    View details for DOI 10.1038/nmat4612

    View details for PubMedID 27005915

  • Surface tension dominates insect flight on fluid interfaces JOURNAL OF EXPERIMENTAL BIOLOGY Mukundarajan, H., Bardon, T. C., Kim, D. H., Prakash, M. 2016; 219 (5): 752-766

    Abstract

    Flight on the 2D air-water interface, with body weight supported by surface tension, is a unique locomotion strategy well adapted for the environmental niche on the surface of water. Although previously described in aquatic insects like stoneflies, the biomechanics of interfacial flight has never been analysed. Here, we report interfacial flight as an adapted behaviour in waterlily beetles (Galerucella nymphaeae) which are also dexterous airborne fliers. We present the first quantitative biomechanical model of interfacial flight in insects, uncovering an intricate interplay of capillary, aerodynamic and neuromuscular forces. We show that waterlily beetles use their tarsal claws to attach themselves to the interface, via a fluid contact line pinned at the claw. We investigate the kinematics of interfacial flight trajectories using high-speed imaging and construct a mathematical model describing the flight dynamics. Our results show that non-linear surface tension forces make interfacial flight energetically expensive compared with airborne flight at the relatively high speeds characteristic of waterlily beetles, and cause chaotic dynamics to arise naturally in these regimes. We identify the crucial roles of capillary-gravity wave drag and oscillatory surface tension forces which dominate interfacial flight, showing that the air-water interface presents a radically modified force landscape for flapping wing flight compared with air.

    View details for DOI 10.1242/jeb.127829

    View details for Web of Science ID 000371134700024

    View details for PubMedID 26936640

  • Synchronous universal droplet logic and control NATURE PHYSICS Katsikis, G., Cybulski, J. S., Prakash, M. 2015; 11 (7): 588-596

    View details for DOI 10.1038/NPHYS3341

    View details for Web of Science ID 000357197300026

  • Diagnosis of Schistosoma haematobium Infection with a Mobile Phone-Mounted Foldscope and a Reversed-Lens CellScope in Ghana AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE Ephraim, R. K., Duah, E., Cybulski, J. S., Prakash, M., D'Ambrosio, M. V., Fletcher, D. A., Keiser, J., Andrews, J. R., Bogoch, I. I. 2015; 92 (6): 1253-1256

    Abstract

    We evaluated two novel, portable microscopes and locally acquired, single-ply, paper towels as filter paper for the diagnosis of Schistosoma haematobium infection. The mobile phone-mounted Foldscope and reversed-lens CellScope had sensitivities of 55.9% and 67.6%, and specificities of 93.3% and 100.0%, respectively, compared with conventional light microscopy for diagnosing S. haematobium infection. With conventional light microscopy, urine filtration using single-ply paper towels as filter paper showed a sensitivity of 67.6% and specificity of 80.0% compared with centrifugation for the diagnosis of S. haematobium infection. With future improvements to diagnostic sensitivity, newer generation handheld and mobile phone microscopes may be valuable tools for global health applications.

    View details for DOI 10.4269/ajtmh.14-0741

    View details for Web of Science ID 000355785400028

    View details for PubMedID 25918211

  • Vapour-mediated sensing and motility in two-component droplets. Nature Cira, N. J., Benusiglio, A., PRAKASH, M. 2015; 519 (7544): 446-450

    Abstract

    Controlling the wetting behaviour of liquids on surfaces is important for a variety of industrial applications such as water-repellent coatings and lubrication. Liquid behaviour on a surface can range from complete spreading, as in the 'tears of wine' effect, to minimal wetting as observed on a superhydrophobic lotus leaf. Controlling droplet movement is important in microfluidic liquid handling, on self-cleaning surfaces and in heat transfer. Droplet motion can be achieved by gradients of surface energy. However, existing techniques require either a large gradient or a carefully prepared surface to overcome the effects of contact line pinning, which usually limit droplet motion. Here we show that two-component droplets of well-chosen miscible liquids such as propylene glycol and water deposited on clean glass are not subject to pinning and cause the motion of neighbouring droplets over a distance. Unlike the canonical predictions for these liquids on a high-energy surface, these droplets do not spread completely but exhibit an apparent contact angle. We demonstrate experimentally and analytically that these droplets are stabilized by evaporation-induced surface tension gradients and that they move in response to the vapour emitted by neighbouring droplets. Our fundamental understanding of this robust system enabled us to construct a wide variety of autonomous fluidic machines out of everyday materials.

    View details for DOI 10.1038/nature14272

    View details for PubMedID 25762146

  • Vapour-mediated sensing and motility in two-component droplets NATURE Cira, N. J., Benusiglio, A., Prakash, M. 2015; 519 (7544): 446-?
  • Punch Card Programmable Microfluidics PLOS ONE Korir, G., Prakash, M. 2015; 10 (3)
  • Punch card programmable microfluidics. PloS one Korir, G., Prakash, M. 2015; 10 (3)

    Abstract

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. A paper tape encodes information as a series of punched holes. A mechanical reader/actuator reads these paper tapes and correspondingly executes operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. Enabled by the complexity of codes that can be represented by a series of holes in punched paper tapes, we demonstrate independent control of 15 on-chip pumps with enhanced mixing, normally-closed valves and a novel on-demand impact-based droplet generator. We demonstrate robustness of operation by encoding a string of characters representing the word "PUNCHCARD MICROFLUIDICS" using the droplet generator. Multiplexing is demonstrated by implementing an example colorimetric water quality assays for pH, ammonia, nitrite and nitrate content in different water samples. With its portable and robust design, low cost and ease-of-use, we envision punch card programmable microfluidics will bring complex control of microfluidic chips into field-based applications in low-resource settings and in the hands of children around the world.

    View details for DOI 10.1371/journal.pone.0115993

    View details for PubMedID 25738834

  • Emergent mechanics of biological structures MOLECULAR BIOLOGY OF THE CELL Dumont, S., Prakash, M. 2014; 25 (22): 3461-3465
  • Emergent mechanics of biological structures. Molecular biology of the cell Dumont, S., Prakash, M. 2014; 25 (22): 3461-3465

    Abstract

    Mechanical force organizes life at all scales, from molecules to cells and tissues. Although we have made remarkable progress unraveling the mechanics of life's individual building blocks, our understanding of how they give rise to the mechanics of larger-scale biological structures is still poor. Unlike the engineered macroscopic structures that we commonly build, biological structures are dynamic and self-organize: they sculpt themselves and change their own architecture, and they have structural building blocks that generate force and constantly come on and off. A description of such structures defies current traditional mechanical frameworks. It requires approaches that account for active force-generating parts and for the formation of spatial and temporal patterns utilizing a diverse array of building blocks. In this Perspective, we term this framework "emergent mechanics." Through examples at molecular, cellular, and tissue scales, we highlight challenges and opportunities in quantitatively understanding the emergent mechanics of biological structures and the need for new conceptual frameworks and experimental tools on the way ahead.

    View details for DOI 10.1091/mbc.E14-03-0784

    View details for PubMedID 25368421

  • Foldscope: Origami-Based Paper Microscope PLOS ONE Cybulski, J. S., Clements, J., Prakash, M. 2014; 9 (6)
  • Probing the Mechanical Coupling of the Cell Membrane to the Nucleus with Vertical Nanopillar Arrays Hanson, L., Urzay, J., Lin, Z., Zhao, W., Prakash, M., Cui, B. CELL PRESS. 2013: 546A-546A
  • Hydraulic stress induced bubble nucleation and growth during pupal metamorphosis Prakash, M. OXFORD UNIV PRESS INC. 2012: E140-E140
  • Flying in two dimensions Prakash, M., Donald, K. OXFORD UNIV PRESS INC. 2012: E141-E141
  • The hungry fly: Hydrodynamics of feeding in the common house fly PHYSICS OF FLUIDS Prakash, M., Steele, M. 2011; 23 (9)

    View details for DOI 10.1063/1.3640023

    View details for Web of Science ID 000295621800010

  • Face-selective electrostatic control of hydrothermal zinc oxide nanowire synthesis NATURE MATERIALS Joo, J., Chow, B. Y., Prakash, M., Boyden, E. S., Jacobson, J. M. 2011; 10 (8): 596-601

    Abstract

    Rational control over the morphology and the functional properties of inorganic nanostructures has been a long-standing goal in the development of bottom-up device fabrication processes. We report that the geometry of hydrothermally grown zinc oxide nanowires can be tuned from platelets to needles, covering more than three orders of magnitude in aspect ratio (~0.1-100). We introduce a classical thermodynamics-based model to explain the underlying growth inhibition mechanism by means of the competitive and face-selective electrostatic adsorption of non-zinc complex ions at alkaline conditions. The performance of these nanowires rivals that of vapour-phase-grown nanostructures, and their low-temperature synthesis (<60 °C) is favourable to the integration and in situ fabrication of complex and polymer-supported devices. We illustrate this capability by fabricating an all-inorganic light-emitting diode in a polymeric microfluidic manifold. Our findings indicate that electrostatic interactions in aqueous crystal growth may be systematically manipulated to synthesize nanostructures and devices with enhanced structural control.

    View details for DOI 10.1038/NMAT3069

    View details for Web of Science ID 000293000000019

    View details for PubMedID 21743451

  • Hydraulic stress induced bubble nucleation and growth during pupal metamorphosis PRAKASH, M. AMER SOC CELL BIOLOGY. 2011
  • Face-selective electrostatic control of nanowire synthesis Nature Materials Joo, J., Chow, B., Prakash, M., Boyden, E., Jacobson, J. 2011; 10: 596-601
  • Interfacial Propulsion by Directional Adhesion International Journal of Non-Linear Mechanics Manu Prakash, John W. M. Bush 2011; 46 (4): 607-615
  • On a tweezer for droplets Advances in Colloid and Interface Science Bush, J., Peaudecerf, F., Prakash, M., Quere, D. 2010; 161: 10-14
  • Drop propulsion in tapered tubes Euro Physics Letters, Renvoise, P., Bush, J., Prakash, M., Quere, D. 2009; 86: 1-5
  • Surface tension transport of prey by feeding shorebirds: The capillary ratchet SCIENCE Prakash, M., Quere, D., Bush, J. W. 2008; 320 (5878): 931-934

    Abstract

    The variability of bird beak morphology reflects diverse foraging strategies. One such feeding mechanism in shorebirds involves surface tension-induced transport of prey in millimetric droplets: By repeatedly opening and closing its beak in a tweezering motion, the bird moves the drop from the tip of its beak to its mouth in a stepwise ratcheting fashion. We have analyzed the subtle physical mechanism responsible for drop transport and demonstrated experimentally that the beak geometry and the dynamics of tweezering may be tuned to optimize transport efficiency. We also highlight the critical dependence of the capillary ratchet on the beak's wetting properties, thus making clear the vulnerability of capillary feeders to surface pollutants.

    View details for DOI 10.1126/science.1156023

    View details for Web of Science ID 000255868300042

    View details for PubMedID 18487193

  • Microfluidic bubble logic SCIENCE Prakash, M., Gershenfeld, N. 2007; 315 (5813): 832-835

    Abstract

    We demonstrate universal computation in an all-fluidic two-phase microfluidic system. Nonlinearity is introduced into an otherwise linear, reversible, low-Reynolds number flow via bubble-to-bubble hydrodynamic interactions. A bubble traveling in a channel represents a bit, providing us with the capability to simultaneously transport materials and perform logical control operations. We demonstrate bubble logic AND/OR/NOT gates, a toggle flip-flop, a ripple counter, timing restoration, a ring oscillator, and an electro-bubble modulator. These show the nonlinearity, gain, bistability, synchronization, cascadability, feedback, and programmability required for scalable universal computation. With increasing complexity in large-scale microfluidic processors, bubble logic provides an on-chip process control mechanism integrating chemistry and computation.

    View details for DOI 10.1126/science.1136907

    View details for Web of Science ID 000244069000065

    View details for PubMedID 17289994

  • The Integument of Water-walking Arthropods: Form and Function Advances in Insect Physiology John W. M. Bush, David L. Hu, Manu Prakash 2007; 34: 117-192
  • Water walking devices Experiments in Fluids Hu, D., Prakash, M., Chan, B., Bush, J. 2007; 43: 769-778
  • Microfludic Bubble Logic Science Prakash, M., Gershenfeld, N. 2007; 315: 832-835
  • Personal fabrication Telektronikk Gershenfeld, N., Prakash, M. 2004; 3: 22-26