Take a peek at our Publications

2024

Unifying Fluidic Excretion Across Life from Cicadas to Elephants

Elio J. Challita, Saad Bhamla. PNAS (2024)

We challenge current notions on fluid ejection by taking a peek at cicada pee. Download the paper.

Epineuston vortex recapture enhances thrust in tiny water skaters

Pankaj Rohilla , Johnathan N. O’Neil , Chandan Bose , Victor M. Ortega-Jimenez , Daehyun Choi , and Saad Bhamla. bioRxiv (2024)

We studied vortex recapture in water striders which boosts it’s speed, helpful in desiging better microrobots. Download the paper.

Controlling noisy herds

Tuhin Chakrabortty, Saad Bhamla. arXiv (2024)

We explored how sheepdogs control small, noisy herds, revealing some fascinating dynamics of herding sheep. Download the paper

Fabricating mesoscale polymer ribbons with tunable mechanical properties via evaporative deposition and dewetting

Cornelia Meissner, Saad Bhamla, Todd Emrick and Alfred J. Crosby. Soft Matter (2024)

We used ‘flow coating’ to create polymer ribbons with specific dimensions and mechanical properties, enabling the design of mesoscale soft materials. Download the paper

Reversible kink instability drives ultrafast jumping in nematodes and soft robots

Sunny Kumar, Ishant Tiwari, Victor M. Ortega-Jimenez, Adler R. Dillman, Dongjing He, Yuhang Hu and Saad Bhamla. bioRxiv (2024)

We studied elastic kinks in tiny nematodes for bidirectional jumping, inspiring designs for soft robots that can jump up to 10 feet through a basketball hoop and on sand. Download the paper

Passive Aerial Righting and Safe Landing of a Small Bio-inspired Jumping Robot

Baekgyeom Kim , Victor M Ortega-Jimenez , M Saad Bhamla , and Je-sung Koh. IEEE (2024)

We studied a bio-inspired jumping robot that achieved controlled, stable landings. Download the paper

Leeches Predate on Fast-Escaping and Entangling Blackworms by Spiral Entombment

Harry Tuazon, Samuel David, Kenneth Ma, and M. Saad Bhamla. ICB (2024)

We explore how leeches capture and consume blackworms despite their rapid escape reflex and tangled blobs. Download the paper

Wax “tails” enable planthopper nymphs to self-right midair and land on their feet

Christina L. McDonald,1 Gerwin T. Alcalde,3, 4 Thomas C. Jones III, Ruby Ana P. Laude, Sheryl A. Yap and M. Saad Bhamla. ICB(2024)

We studied wax 'tails' on planthopper nymphs that help stabilize flight, aiding landings through aerodynamic drag, and shedding light on insect flight evolution and robotics. Download the paper

Limb loss and specialized leg dynamics in tiny water-walking insects

Johnathan N. O’Neil, Kai Lauren Yung, Gaetano Difini, Pankaj Rohilla and M. Saad Bhamla. ICB(2024)

We studied that microvelia's hind tarsi act as 'rudders' for water walking, guiding directionality and adaptation to limb loss, with further applications to develop micro-robot design. Download the paper

Tiny Amphibious Insects Use Tripod Gait for Traversal on Land, Water, and Duckweed

Johnathan N. O’Neil , Kai Lauren Yung, Gaetano Difini, Holden Walker and M. Saad Bhamla. ICB(2024)

This study shows how microvelia's tripod gait across water and land, adjusting leg strides to duckweed, showcases adaptability for survival and further applications in robotics. Download the paper

Tolerability of a piezoelectric microneedle electroporator in human subjects

Chao-Yi Lu, Pankaj Rohilla, Eric l. Felner, Gaurav Byagathvalli, Erkan Azizoglu, M. Saad Bhamla, Mark R. Prausnitz. Bioengineering and Translational Medicine (2024)

This work shows excellent human tolerance of electroporation via our ePatch device in human subjects. Download the paper

Fluid ejections in nature

Elio J. Challita, Pankaj Rohilla, M. Saad Bhamla, Annual Review of Chemical and Biomolecular Engineering (2024)

We review a range of fluid ejections in nature and provide a framework to understand how fluid transport varies across organisms. Download the paper

OpenCell: A Low-cost, Open-Source, 3-in-1 device for DNA Extraction

Aryan Gupta, Justin Yu, Elio J. Challita, Janet Standeven, M. Saad Bhamla. PLoS One (2024)

We’ve created OpenCell, a 'lab-in-a-backpack' that combines the functionalities of a bead homogenizer, a microcentrifuge, and a vortex mixer. Download the paper

Trackoscope: A Low-Cost, Open, Autonomous Tracking Microscope for Long-Term Observations of Microscale Organisms

Priya Soneji, Elio J. Challita, M. Saad Bhamla. (2024)

We have built a hassle-free, low-cost solution for tracking organisms under a microscope. Download the paper

2023

Ultrafast reversible self-assembly of living tangled matter

Vishal P. Patil, Harry Tuazon, Emily Kaufman, Tuhin Chakrabortty, David Qin, Jörn Dunkel, M. Saad Bhamla. Science (2023)

We uncover how worms solve a `Gordian Knot’ problem to untangle in milliseconds using a helical wave resonance mechanism. Download the paper

Droplet superpropulsion in an energetically constrained insect

Elio J. Challita, Prateek Sehgal, Rodrigo Krugner, and M. Saad Bhamla. Nature Communications (2023)

We show how and why millimeter-scale sharpshooter insects exploit droplet superpropulsion to eliminate their droplet excreta. Download the paper

Conservation tools: the next generation of engineering–biology collaboration

Andrew K. Schulz, Cassie Shriver, Suzanne Stathatos, Benjamin Seleb, Emily G. Weigel, Young-Hui Chang, M. Saad Bhamla, David L. Hu and Joseph R. Mendelson III, Royal society interface (2023)

We introduce the concept of Conservation Tools, presenting specific case studies and a framework that showcases diverse tools, including eDNA, Frugal Science, Open-source innovation, CV, and Game Theory, for innovative wildlife conservation and environmental protection. Download the paper

Effect of fines percentage on ultrasonic dewatering of cellulose nanofibrils

Udita Ringania, Robert J. Moon, M. Saad Bhamla, Cellulose (2023)

We test our method of ultrasonic dewatering of Cellulose Nanofibrils (CNFs) suspensions on differing fines percentages. Download the paper

A unified model for the dynamics of ATP-independent ultrafast contraction

Carlos Floyd, Arthur T. Molines, Xiangting Lei, Jerry E. Honts, Fred Chang, Mary Williard Elting, Suriyanarayanan Vaikuntanathan, Aaron R. Dinner, M. Saad Bhamla. PNAS (2023)

We develop a minimal model for calcium-driven supramolecular springs that power some of life’s ultrafast single-celled motions. Download the paper

Collecting-gathering biophysics of the blackworm l. Variegatus

Harry Tuazon, Chantal Nguyen, Emily Kaufman, Ishant Tiwari, Jessica Bermudez, Darshan Chudasama, Orit Peleg, M. Saad Bhamla. Integrative & Comparative Biology (2023).

We quantitatively describe the collecting-gathering behavior of California blackworms through experiments with varying population sizes and accompanying simulations. Download the paper

worm blobs as entangled living polymers: from topological active matter to flexible soft robot collectives

Antoine Deblais, K. R. Prathyusha, Rosa Sinaasappel, Harry Tuazon, Ishant Tiwari, Vishal P. Patil, M. Saad Bhamla. Soft Matter (2023)

We look at worm blobs as active entangled polymers, through reevaluating concepts in polymer physics to advance the development of active polymers. Download the paper

Air-to-land transitions: from wingless animals and plant seeds to shuttlecocks and bio-inspired robots

Victor M. Ortega-Jimenez, Ardian Jusufi, Christian Brown, Yu Zeng, Sunny Kumar, Robert Siddall, Baekgyeom Kim, Elio Challita, Zoe Pavlik, Meredith Priess, Thomas Umhofer, Je-Sung Koh, John J. Socha, Robert Dudley, M. Saad Bhamla. Bioinspiration & Biomimetics (2023)

In this review, we examine the current state of the art for aerial righting and landing maneuvers in wingless organisms, plant seeds, sports projectiles, and robots. Download the paper

Comparing outcomes of ultra-low-cost hearing aids to programmable, refurbished hearing aids for adults with high frequency hearing loss in Malawi: A feasibility study

Bhavisha Parmar, Mwanaisha Phiri, Louis Jailos, Regina Kachapila, Benjamin Saleb, Wakisa Mulwafu4, Vinay Manchaiah and M. Saad Bhamla, Frontiers in Rehabilitating Sciences (2023)

In this pilot study, we compare our LoCHAid to programmable refurbished hearing aids and gather user perspectives in individuals with high-frequency hearing loss. Download the paper

The origin of blinking in both mudskippers and tetrapods is linked to aerial vision and life on land

Aiello BR, M. Saad Bhamla, J Gau, JGL Morris, K Bomar, S da Cunha, H Fu, J Laws, H Minoguchi, M Sripathi, K Washington, G Wong, NH Shubin, S Sponberg, TA Stewart. PNAS (2023)

We uncover how and why we blink. Download the paper

Amorphous entangled active matter

William Savoie, Harry Tuazon, Ishant Tiwari, M. Saad Bhamla, and Daniel I. Goldman. Soft Matter (2023)

We show how entanglement can be controlled in a collective of u-shaped particles (“smarticles”) and in living entangled worm blobs. Download the paper

2022

Directional takeoff, aerial righting, and adhesion landing of semiaquatic springtails

Ortega-Jimenez, Victor M., Elio J. Challita, Baekgyeom Kim, Hungtang Ko, Minseok Gwon, Je-Sung Koh, and M. Saad Bhamla. PNAS (2022)

We uncovered how tiny springtails control their jump and landing on the surface of water by combing experiments, mathematical modeling and robotics. Download the paper

Oxygenation-Controlled Collective Dynamics in Aquatic Worm Blobs

Harry Tuazon, Emily Kaufman, Daniel I. Goldman and M. Saad Bhamla. Integrative and Comparative Biology (2022)

We uncovered that worms blobs change how tightly they are tangled based on the dissolved oxygen in the surrounding environment. Download the paper

A Tunable, Simplified Model for Biological Latch Mediated Spring Actuated Systems

Andrés Cook, Kaanthi Pandhigunta, Mason A Acevedo, Adam Walker, Rosalie L Didcock, Jackson T Castro, Declan O’Neill, Raghav Acharya, M. Saad Bhamla, Philip S L Anderson, Mark Ilton. Integrative Organismal Biology (2022)

We develop a model of latch-mediated spring actuated (LaMSA) systems relevant to comparative biomechanics and bioinspired design. Download the paper

Reshaping sub-millimetre bubbles from spheres to tori

Xujun Zhang, Shane Jacobeen, Qiang Zhang, Brian Khau, Peter Yunker, H Jerry Qi, M. Saad Bhamla, Paul S Russo. Soft Matter (2022)

We show how a thin, elastic film stabilizes submillimeter bubbles, to transform them reversibly from toroidal to spherical shape. Download the paper

Design of a Biologically Inspired Water-Walking Robot Powered by Artificial Muscle

Dongjin Kim, Minseok Gwon, Baekgyeom Kim, Victor M Ortega-Jimenez, Seungyong Han, Daeshik Kang, M Saad Bhamla, Je-Sung Koh. Micromachines (2022)

We developed a lightweight, fast-turning and controllable water-strider inspired robot for agile locomotion on the surface of water. Download the paper

Dewatering of cellulose nanofibrils using ultrasound

Udita Ringania, Joseph Harrison, Robert J. Moon and M. Saad Bhamla. Cellulose (2022)

To address the high energy requirements of drying cellulosic materials, we developed a frugal ultrasound-based platform to dewater Cellulose Nanofibrils (CNFs). Download the paper

2021

The ultrafast snap of a finger is mediated by skin friction

Raghav Acharya, Elio Challita, Mark Ilton and M. Saad Bhamla. Journal of the Royal Society Interface (2021)

Oh Snap! We uncover the physics of a finger snap. Download the paper

Frugal Science Powered by curiosity

Gaurav Byagathvalli, Elio Challita and M. Saad Bhamla. Industrial & Engineering Chemistry Research (2021)

Inspired by Feynman’s call, we both define `frugal science’ and invite chemists, biologists, physicists, bioengineers, educators, high school students, and inventors of all backgrounds to join is in this emerging field of frugal science to address planetary-scale challenges. Download the paper

An ultra-low-cost electroporator with microneedle electrodes (ePatch) for SARS-CoV-2 vaccination

Dengning Xia, Rui Jin, Gaurav Byagathvalli, Huan Yu, Ling Ye, Chao-Yi Lu, M. Saad Bhamla, Chinglai Yang, and Mark R. Prausnitz. PNAS (2021)

Inspired by a BBQ lighter, we developed a frugal `ePatch’ for DNA vaccine delivery. Download the paper

Emergent Collective Locomotion in an Active Polymer Model of Entangled Worm Blobs

Chantal Nguyen, Yasemin Ozkan-Aydin, Harry Tuazon, Daniel I. Goldman, M. Saad Bhamla & Orit Peleg. Frontiers in Physics (2021)

How do worm blobs move? In this paper we develop active polymer models to understand emergent blob locomotion in thermal gradients. Download the paper

Slingshot spiders build tensed, underdamped webs for ultrafast launches and speedy halts

Elio J. Challita, Symone L. M. Alexander, Sarah I. Han, Todd A. Blackledge, Jonathan A. Coddington, Sunghwan Jung & M. Saad Bhamla. Journal of Comparative Physiology A (2021)

We develop a mathematical model that describes the dynamics of the slingshot spider given its unique conical web structure. Download the paper

Collective dynamics in entangled worm and robot blobs

Yasemin Ozkan-Aydin, Daniel I. Goldman, M. Saad Bhamla. PNAS (2021)

Here we describe a new living entangled active matter collective: worm blobs. We describe their biological function, biomechanics and applications in designing robotic collectives. Download the paper

2020

LoCHAid: An ultra-low-cost hearing aid for age-related hearing loss

Soham Sinha, Urvaksh D. Irani, Vinaya Manchaiah, M. Saad Bhamla. PLOS One (2020)

Learn more about our latest frugal invention - a $1 hearing aid. Download the paper

Ultrafast launch of slingshot spiders using conical silk webs

Symone L.M. Alexander and M. Saad Bhamla. Current Biology (2020)

Here we describe our discovery of ultrafast motion in Slingshot Spiders, one of the fastest spiders. These spiders build high power conical webs as springs to catapult themselves. Download the paper

PoPPR: a polymer based technique to remove pollutants from soft contact lenses

Katherine Burgener and Saad Bhamla. Contact Lens and Anterior Eye (2020)

A new polymer-based technique (PoPPR) to remove pollen, microbeads and nanoparticles from soft contact lenses. PDF

ElectroPen: An ultra-low–cost, electricity-free, portable electroporator

Gaurav Byagathvalli, Soham Sinha, Yan Zhang, Mark Styczynski, Janet Standeven, M. Saad Bhamla. PLOS Biology 2020

The latest device in our frugal science work - a 20-cent electroporator or ElectroPen. Read on to find out how a bbq gas lighter works, and how we harnessed its potential to develop the worlds cheapest electroporator. PDF

2019

Biophysical mechanism of ultrafast helical twisting contraction in the giant unicellular ciliate Spirostomum ambiguum

L.X. Xu and M. Saad Bhamla. BioRxiv 2019

Here, we present a mechanism for the ultrafast contraction exhibited by the unicellular ciliate Spirostomum ambiguum. We employ confocal microscopy to understand cytoskeletal structures and physical actuators to explain twisting contraction. PDF

Collective intercellular communication through ultra-fast hydrodynamic trigger waves

Arnold Mathijssen, Joshua Culver, M. Saad Bhamla, Manu Prakash. Nature, 2019

Have you wondered how single cells communicate across long-distances using fluid waves? Wonder no more! In this work, we describe how an extreme single cell (Spirostomum) contracts its body super-fast to generate hydrodynamic waves, that lead to propagation of information in cell clusters. PDF

A 3D-printed hand-powered centrifuge for molecular biology

Gaurav Byagathvalli, Aaron Pomerantz, Soham Sinha, Janet Standeven, M. Saad Bhamla. PLOS Biology, 17(5):e3000251.

Building on our 20-cent paper centrifuge (paperfuge), we show a 3D-printed centrifuge molecular biology. This increases the volume capacity of the paperfuge up to 2ml and shows new applications in field biology and high schools. PDF

2018

The principles of cascading power limits in small, fast biological and engineered systems

Mark Ilton, M. Saad Bhamla*, Xiaotian Ma*, Suzanne M. Cox*, Leah L. Fitchett, Yongjin Kim, Je-sung Koh, Deepak Krishnamurthy, Chi-Yun Kuo, Fatma Zeynep Temel, Alfred J. Crosby, Manu Prakash, Gregory P. Sutton, Robert J. Wood, Emanuel Azizi, Sarah Bergbreiter, and S. N. Patek. Science, 360.6387 eaao1082 (2018)

Fast biological and engineered movements are unified via a mathematical model, conceptual framework, and literature analysis. PDF

2017

Hand-powered ultralow-cost paper centrifuge

M. Saad Bhamla, Brandon Benson*, Chew Chai*, Georgios Katsikis, Aanchal Johri, Manu Prakash. Nature Biomedical Engineering, 1 0009 (2017)

Commercial centrifuges are expensive, bulky and electricity-powered, and create a bottleneck for sample preparation in point-of-care diagnostics. To address this urgent need, we invented an ultralow-cost (20 cents),  human-powered paper centrifuge (paperfuge) inspired by a children's toy. The paperfuge achieves a world-record speed of 125,000 r.p.m. and  can separate pure plasma from whole blood in less than 1.5 min, and isolate malaria parasites in 15 min.​ Also see Research Highlight in Nature Biomedical Engineering. PDF

Interfacial mechanisms for stability of surfactant-laden films

Bhamla, M.S., Chai C., Alvarez M., Tajuelo J., and Fuller G.G. PLOS One,12 (5), p.e0175753, (2017)

Do soluble and insoluble surfactants stabilize films in the same way? Read more to learn how surfactants exploit different interfacial mechanisms to create stable thin films. PDF

2016

Placing Marangoni instabilities under arrest

Bhamla, M.S. and Fuller, G.G. Physical Review Fluids, 1(5), 050506 (2016)

This video is a compilation of curiosity-driven experiments that systematically investigate the surface flows on a rising soap bubble. From childhood experience, we are familiar with the vibrant colors and mesmerizing display of chaotic flows on the surface of a soap bubble. These flows arise due to surface tension gradients, also known as Marangoni flows or instabilities. In this video, we show the surprising effect of layering multiple instabilities on top of each other, highlighting that unexpected new phenomena are still waiting to be discovered, even in the simple soap bubble.

**Won the Milton van Dyke award at APS DFD 2015. Video Link PDF

Instability and breakup of model tear films

Bhamla, M.S., Chai C., Rabiah N.I., Frostad J.M., and Fuller, G.G. Investigative Ophthalmology and Visual Science, 57:949–958 (2016)

Using our patented Interfacial Dewetting and Drainage Optical Platform (i-DDrOP), we shed clarification on a longstanding puzzle about the evaporative properties of the human tear film lipid layer. Also see Research Highlight in IOVS. PDF

2015

Lung surfactants and different contributions to thin film stability

Hermans, E.*, Bhamla, M.S., Kao P., Fuller, G.G. and Vermant, J. Soft Matter, 11.41:8048-57 (2015)

In premature infants suffering from respiratory distress, surfactant replacements are injected to facilitate breathing. Why do these surfactant replacements have varied efficacies and mortality rates? How can we better design synthetic therapeutics? Collaborating with ETH Zurich and Stanford Hospital, we examined various FDA-approved replacements. We successfully identified critical interfacial rheological properties that can optimize clinical efficacy of these therapeutics as well benefit design of better synthetic pulmonary surfactant replacements. PDF

Influence of lipid coatings on surface wettability characteristics of silicone hydrogels

Bhamla, M.S., Nash W., Elliott S., and Fuller, G.G. Langmuir, 31 (13), 3820- 3828 (2015)

How does bio-fouling affect the surface wettability of soft contact lenses? In collaboration with industrial partners, we describe a new methodology to examine the in-vitro deposition of model tear film lipids and its consequence on surface wetting on silicone hydrogel contact lenses.  PDF

Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates

Bhamla, M.S., Balemans, C., and Fuller, G.G. J. Colloid and Interface Science, 449, 428-435 (2015)

Blink! Between blink cycles, the tear film on your eyes breaks up and dewets the corneal epithelium (or the contact lens surface), and needs to be constantly refreshed by blinking. What parameters control the onset of this dewetting instability? To gain insight, we examine the fascinating dewetting dynamics of model tear films laden on soft contact lenses. PDF

2014

Influence of interfacial rheology on drainage from curved surfaces

Bhamla, M.S., Giacomin, C. E., Balemans, C., and Fuller. Soft Matter, 10.36: 6917-6925 (2014)

Why do tear-film lipids posses rheologically complex properties? Inspired by lubricating flows on our eyes, we demonstrate that the interfacial rheology of these lipid layers leads to significant slowing down of draining aqueous films, which has important implications for the stability of the human tear film. PDF

Pre-2013

Autonomous motility of active filaments due to spontaneous flow- symmetry breaking

Jayaraman, G., Ramachandran, S., Ghose, S., Laskar, A., Bhamla, M.S., Kumar, PS, and Adhikari R. Physical Review Letters, 109(15), 158302 (2012)

How does a cytoskeleton, consisting of biopolymers with molecular motors walking on them respond to external forces? We model such a polymer as an elastic filament with a permanent distribution of stresslets along its contour.  We find that filaments spontaneously break flow symmetry resulting in autonomous motion. PDF

Extrudate swell of linear and branched polyethylenes: ALE simulations and comparison with experiments

Ganvir, V., Gautham, B.P., Pol, H., Bhamla, M.S., Sclesi, L., Thaokar, R., Lele, A.K., Mackley, M. Journal of Non- Newtonian Fluid Mechanics, 166(1) (2011)

Can we accurately model free surface flows in polymeric melts?  We model extrusion swelling of linear and branched polyethylene polymers using ALE based finite element simulations and show good agreement with experimental birefringence data. PDF