Sumit Mohanty | KTH Royal Institute of Technology (original) (raw)

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Papers by Sumit Mohanty

Advanced Science

Technical design features for improving the way a passive elastic filament produces propulsive th... more Technical design features for improving the way a passive elastic filament produces propulsive thrust can be understood by analyzing the deformation of sperm-templated microrobots with segmented magnetization. Magnetic nanoparticles are electrostatically self-assembled on bovine sperm cells with nonuniform surface charge, producing different categories of sperm-templated microrobots. Depending on the amount and location of the nanoparticles on each cellular segment, magnetoelastic and viscous forces determine the wave pattern of each category during flagellar motion. Passively propagating waves are induced along the length of these microrobots using external rotating magnetic fields and the resultant wave patterns are measured. The response of the microrobots to the external field reveals distinct flow fields, propulsive thrust, and frequency responses during flagellar propulsion. This work allows predictions for optimizing the design and propulsion of flexible magnetic microrobots with segmented magnetization.

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences

Acoustic actuation techniques offer a promising tool for contactless manipulation of both synthet... more Acoustic actuation techniques offer a promising tool for contactless manipulation of both synthetic and biological micro/nano agents that encompass different length scales. The traditional usage of sound waves has steadily progressed from mid-air manipulation of salt grains to sophisticated techniques that employ nanoparticle flow in microfluidic networks. State-of-the-art in microfabrication and instrumentation have further expanded the outreach of these actuation techniques to autonomous propulsion of micro-agents. In this review article, we provide a universal perspective of the known acoustic micromanipulation technologies in terms of their applications and governing physics. Hereby, we survey these technologies and classify them with regards to passive and active manipulation of agents. These manipulation methods account for both intelligent devices adept at dexterous non-contact handling of micro-agents, and acoustically induced mechanisms for self-propulsion of micro-robots. ...

Sensors and Actuators B: Chemical

Advanced Intelligent Systems

Science Advances

We develop biohybrid magnetic microrobots by electrostatic self-assembly of nonmotile sperm cells... more We develop biohybrid magnetic microrobots by electrostatic self-assembly of nonmotile sperm cells and magnetic nanoparticles. Incorporating a biological entity into microrobots entails many functional advantages beyond shape templating, such as the facile uptake of chemotherapeutic agents to achieve targeted drug delivery. We present a single-step electrostatic self-assembly technique to fabricate IRONSperms, soft magnetic microswimmers that emulate the motion of motile sperm cells. Our experiments and theoretical predictions show that the swimming speed of IRONSperms exceeds 0.2 body length/s (6.8 ± 4.1 µm/s) at an actuation frequency of 8 Hz and precision angle of 45°. We demonstrate that the nanoparticle coating increases the acoustic impedance of the sperm cells and enables localization of clusters of IRONSperm using ultrasound feedback. We also confirm the biocompatibility and drug loading ability of these microrobots, and their promise as biocompatible, controllable, and detec...

Micromachines

As robotic tools are becoming a fundamental part of present day surgical interventions, microrobo... more As robotic tools are becoming a fundamental part of present day surgical interventions, microrobotic surgery is steadily approaching clinically-relevant scenarios. In particular, minimally invasive microrobotic targeted drug deliveries are reaching the grasp of the current state-of-the-art technology. However, clinically-relevant issues, such as lack of biocompatibility and dexterity, complicate the clinical application of the results obtained in controlled environments. Consequently, in this work we present a proof-of-concept fully contactless and biocompatible approach for active targeted delivery of a drug-model. In order to achieve full biocompatiblity and contacless actuation, magnetic fields are used for motion control, ultrasound is used for imaging, and induction heating is used for active drug-model release. The presented system is validated in a three-dimensional phantom of human vessels, performing ten trials that mimic targeted drug delivery using a drug-coated microrobo...

AIP Advances

We show that vibrating protrusions inside a microchannel are capable of steering fluid away from ... more We show that vibrating protrusions inside a microchannel are capable of steering fluid away from their relative orientation. This phenomenon is brought forth by symmetry-broken design of these protrusions. Vibration of these asymmetric protrusions is reciprocated in the streaming effect at the boundary layers of the channel thus inducing a net fluid flow. Additionally, we show that the flow direction is sensitive to switching acoustic frequencies. This acoustically-induced flow has the potential for transportation of nanoparticles as well as complex micro-structures. We hereby demonstrate this utility for contactless actuation of flagellar micro-agents as a foreground towards targeted drug release.

IEEE Robotics and Automation Letters

Advancements in medical microrobotics have given rise to an abundance of agents capable of locali... more Advancements in medical microrobotics have given rise to an abundance of agents capable of localised interaction with human body in small scales. Nevertheless, clinically-relevant applications of this technology are still limited by the auxiliary infrastructure required for actuation of micro-agents. In this letter, we approach this challenge. Using finite-element analysis, we show that miniaturization of electromagnets can be used to create systems capable of providing magnetic forces adequate for micro-agent steering, while retaining small footprint and power consumption. We use these observations to create MILiMAC (Microrobotic Infrastructure Loaded into Magnetically-Actuated Catheter). MILiMAC is a flexible catheter employing three miniaturized electromagnets to provide localized magnetic actuation at the deeply-seated microsurgery site. We test our approach in a proof-of-concept study deploying MILiMAC inside a test platform to deliver and steer a 600 [µm] ferromagnetic microbead. The bead is steered along a set of user-defined trajectories using closed-loop position control. Across all trajectories the best performance metrics are the mean error of 0.41 [mm] and the steady-state error of 0.27 [mm]. Index Terms-Medical robots and systems, micro/nano robots. I. INTRODUCTION M ICROROBOTIC surgery is a future medical technology with the potential of revolutionising the way clinicians interact with human body. Employing functional miniaturized agents and controlling them in vivo could allow for localized and selective engagement of human body on cellular and tissue organization levels [1]. Such capabilities would complement contemporary medicine, which excels in procedures targeting entire organs, as well as in systemic treatment through delivery of therapeutic substances via the bloodstream.

$Research paper thumbnail of Stereo-holographic diffraction based tracking of microrobots$

Three dimensional tracking of microrobots is demonstrated using stereo holographic projections. T... more Three dimensional tracking of microrobots is demonstrated using stereo holographic projections. The method detects the lateral position of a microrobot in two orthogonal in-line holography images and triangulates to obtain the 3-D position in an observable volume of one cubic cm. The algorithm is capable of processing holograms at 25Hz on a desktop computer and has an accuracy of 24.7μm and 15.2μm in the two independent directions and 7.3μm in the shared direction of the two imaging planes. This is the first use of stereo holograms to track an object in real-time and does not rely on the computationally expensive process of holographic reconstruction.

Carbon nanotubes (CNT) due to its multifunctional characteristics has been presented as a flame s... more Carbon nanotubes (CNT) due to its multifunctional characteristics has been presented as a flame sensor by combining both radiation and chemical sensitivity. Chemical functionalization enhances the sensitivity of CNT sensor toward any chemical modifications that are induced by the flame. Response of the sensor is revealed to be dependent on the measurement direction (longitudinal and transverse) as well as the radiation intensity. A nonlinear relation between the sensitivity and its distance from the source is used to calibrate the intensity of the flame. The present method allows a simpler approach for the flame detection by utilizing a calibration scheme to operate at any particular bias current and tune its sensitivity with respect to any working distance at a particular bias current.

Thesis Chapters by Sumit Mohanty

$Research paper thumbnail of Fabrication and tracking of ABFs using stereo-holographic diffraction$

Den framväxande området mobila mikrorobotik ses kunna användas för en mängdolika tillämpningar, f... more Den framväxande området mobila mikrorobotik ses kunna användas för en mängdolika tillämpningar, från intelligent mikromanipulering till att diversifiera möjligheternaför minimalt invasiva operationer. Flera utformningar av mikrorobotar har föreslagitsoch studeras notoriskt för att öka kunskapen om deras beteende i olika miljöerför att se hur dessa kan förbättras och användas för dessa ändamål. I dagslägetkontrolleras och övervakas mikrorobotara med hjälp av en konvergens av olikatekniker som; magnetisk aktivering, mikroskopi och data igenkänning. Kunskapenom hur mikrorobotarna agerar i olika miljoer gör att vi kan utveckladessa mikrorobotar i sina kommande tillämpningar.I samband med att bredda denna förståelse för deras beteende har era metoderföreslagits för att studera och kontrollera dessa mikrorobotar, som t.ex att utnyttjadessa för mikroskopi för visuell övervakning från två håll. Den uppenbaranackdelen med mikroskopi är att den äventyrar noggrannheten genom att endastfokusera på vissa delar, vilket begränsar dessa studier till att inte observera helheten.På grund av dessa begränsningar av konventionell mikroskopi har holografiundersökts som ett alternativ för avbildning och spatial spårning av dessa mikrorobotargenom att rekonstruera 2-D informationen som ges i bilderna. Uppskattningav till vilket djup upplösning håller samt tidåtgången föråteruppbyggnadenav bilderna är dock två nackdelar för holografins användbarhet. Det nya förfarandetsom föreslås i denna rapport, har en utgångspunkt i holografisk avbildning i syfteför denna funktion i dubbelseende och för att övervinna de begränsningar somfinns hos både konventionell mikroskopi och holografisk rekonstruktion. Tidsbesparingarnaför att behandla denna bildinformation på en lägre bearbetningshastighetär en ytterliggare faktor till varför en holografisk metod är väsentligför spatial spårning av mikrorobotar. Den nyskapande installationsutformningensom föreslås i denna rapport är inspirerad av konventionellt dubbelseende.Det innebär också att spårningsprocessen av en klass av agellated mikrorobotarkallas Artificiell Bakterieagella (ABF) baserat på hämtning av sina tvådifiraktionsbaserade hologram, och uppskatta dess 3-D-läge baserat på sido positioneri de två bildprognoserna. Den föreslår vidare genomförbara konstruktionsmått för tillverkning av dessa ABFs baserade på Fresnel difiraktionerna.Den centrala idén bakom denna 3-D uppskattning som föreslås här bygger på en bearbetning av difiraktionsmönsterna som produceras av ABFs med hjälp aven bildsegment-algoritm och ytterligare utskjutande sidokoordinater erhållna tillverkligt utrymme, och på så vis uppnår en mer konkret djupupplösningen i endera riktningen.