Collective protection and transport in entangled biological and robotic active matter

Yasemin Ozkan-Aydin, Daniel I. Goldman, M. Saad Bhamla

BioRxiv (2020)

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

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.

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.

LoCHAid - a $1 low-cost hearing aid for age related hearing loss

Soham Sinha, Urvaksh Irani, Vinay Manchaiah, Saad Bhamla


Read about our latest invention from the lab of a low-cost hearing aid to enable affordable and accessible hearing for elderly patients suffering from age related hearing loss (ARHL).

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.

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. 

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

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.

Hand-powered ultralow-cost paper centrifuge

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

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.

Placing Marangoni instabilities under arrest

Bhamla, M.S. and Fuller, G.G.

Physical Review Fluids, 1(5), 050506 (2016)

Soap bubbles occupy the rare position of delighting and fascinating both young children and scientific minds alike. Sir Isaac Newton, Joseph Plateau, Carlo Marangoni and Pierre-Gilles de Gennes, not to mention countless others, have discovered remarkable results in optics, molecular forces and fluid dynamics from investigating this seemingly simple system.

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

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.

Alse see Research Highlight in IOVS.

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.

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.   

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

Bhamla, M.S., Balemans, C., and Fuller, G.G.

Journal of 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.

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.

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.

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.

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