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Brief Profile of the Awardee

awardee

Dr Ambarish Ghosh

  • 2018
  • Physical Sciences
  • 18/12/1973
  • Soft Matter Physics, Optics and Low Temperature Physics
Award Citation:

Academic Qualifications:
NA
Thesis and Guide details:
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Details of CSIR Fellowship/ Associateship held, if any or from other sources/ agencies.
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Significant foreign assignments:
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(a) Significant contributions to science and/ or technology development by the nominee based on the work done in India during most part of last 5 years:
A major focus of the research carried out by the nominee has been the development of a versatile system of motile colloids, which is of current fundamental (active matter, soft matter physics) and technological (microfluidics, biophysics, drug delivery) interest. The experimental system is based on helical magnetic nanostructures (nanoswimmers [1]) dispersed in fluidic environments, which can be maneuvered under the action of rotating/oscillating magnetic [2] fields. Over last few years, the nominee has made various important contributions in understanding and expanding the scope of this powerful nanosystem. Dynamics of the magnetic nanoswimmers: The group led by nominee carried out detailed experimental study of the dynamics [3] of the nanoswimmers, performed numerical simulations, and derived analytical [4] formula that explains the experimental observations accurately. They have discovered chaotic bistable dynamics under certain experimental conditions, which was a surprising observation considering this was a typical low Reynolds number environment but could be understood from the numerical and analytical studies. They studied the effect of thermal fluctuations [5] on the motion of the nanoswimmers and predicted the size below which helical propulsion is rendered useless. The study consisted of both theoretical and experimental aspects, which will impact the design of practical nano-propulsion systems. Crucially, the study of the dynamics has given rise to an interesting technology [6] (patent applied), where the propellers could be used to measure mechanical properties (viscosity) of complex (e.g. shear thinning) and heterogeneous fluidic environments with very high spatial resolution and extremely high speed. From driven system to all magnetic active matter: Standard helical propulsion with externally applied torques results in motion whose direction is tied to the characteristics of the driving torque. This contrasts with selfpropelled systems, such as living bacteria or catalytic swimmers, whose directions are entirely governed by orientation diffusion and fluidic interactions. For making intelligent nanoscale systems, the constituents need to be self-propelled. This fundamental limitation for the helical swimmers was overcome by developing an all magnetic active matter, which was also the first demonstration of a “reciprocal swimmer” [7]. An interesting extension of this idea has allowed them to demonstrate independent positioning [8] of two nanoswimmers that are of identical shape and size. Extending upon the method to obtain reciprocal motion, now the nominee has devised a method to operate this system as non-reciprocal swimmers (manuscript under preparation) as well. Considering their interaction to be mainly hydrodynamic in nature, with a level of activity that can be tuned externally, surely this novel system of artificial swimmers will provide a powerful platform to investigate active matter phenomena. During these studies, they have discovered an interesting self-purification [9] phenomenon where external (passive) dopants were found to permanently internalize or spontaneously eject out of a host system (here, confined colloidal crystallites) depending on the position of the dopant. New interesting phenomena are expected to emerge from these studies, which have been extended to active hosts and dopants (using nanoswimmers: manuscript in preparation). Biological environments, including intracellular spaces: There are plenty of biomedical applications possible with the magnetic nanoswimmers, and surely this patented [10] technology is moving toward clinical studies within a few years.
(b) Impact of the contributions in the field concerned:
The contributions made by the nominee on magnetic nanoswimmers is mostly applied in nature, where several new technologies have been developed, which typically originated from a detailed investigation of certain fundamental phenomena. For example, investigation of the rigid body dynamics of the swimmers under external torque [3] led to analytical expressions [4] which incorporated the rheological parameters of the surrounding medium. These expressions formed the basis of a new microrheological technique [6] that are applicable to Newtonian and shear-thinning media. A similar example is related to attempts made by the nominee to make the system self-propelled [7], which in turn led to a new nanomanipulation technique, where the swimmers can be positioned independently [8] in microfluidic devices. On fundamental side, the development of an all magnetic self-propelled system based on helical swimmers will be of great interest to the active matter community. Similarly, the nominee investigated the limits of electromagnetic near field enhancement for a plasmonic dimer, for which he developed an experimental system comprising of a novel dimer-graphene sandwich configuration. While this study provided great insight into the details of near field enhancement, it also resulted in record enhancement of graphene photoresponsivity [19], which is important in 2D material based optoelectronic technologies. The integration of plasmonics with helical nanostructures not only resulted in metamaterials with strong chiro-optical response [16] but have also resulted in the development of a mobile nanotweezer [20] which can lead to novel and impactful microfluidic technologies pertaining to colloidal manipulation and nanoscale assembly. Undoubtedly, the biggest impact of the nanoswimmers in the long term will be in the field of targeted drug delivery, for which he has made crucial contributions. The nominee has led an interdisciplinary group of scientists to achieve voyage of the swimmers through human blood [11] and inside living cells [13]. The experience in maneuvering through such important biological media will surely be followed by deploying these nanoprobes in live animals, and hopefully someday in humans. Apart from magnetic nanoswimmers and plasmonics, a certain aspect of the research carried out by the nominee has very strong fundamental value. While certain interesting results came by chance, as was the discovery of self-purification of colloidal crystallites [9], the nominee has developed a research program on multielectron bubbles or MEBs in liquid helium over last few years. The goal of this research program is to discover quantum melting of a Wigner crystal in 2D, and MEBs are promising candidates as an experimental system for observing these phase transitions. In an important breakthrough, the group led by the nominee was able to trap the MEBs [21] using a Paul trap, which may be a crucial step in achieving these ambitious goals.
Places where work of last 5 years has been referred/ cited in Books, Reviews:
(i). Paper Cited
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(ii). Book Cited
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Names of the industries in which the technology (ies) has (have) been used :
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The achievements already been recognised by Awards by any learned body:
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The Awardee a fellow of the Indian National Science Academy/Indian Academy of Sciences/National Academy of Sciences/Others:
The Awardee delivered invited lecture(s) in India/abroad and/or chaired any scientific Internatiional Conference Symposium:
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List of Awardee's 10 most significant publications.
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List of Awardee's 5 most significant publications during the last 5 years
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List of Awardee's 5 most significant publications from out of work done in India during the last five years:
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Complete list of publications in standard refereed journals:
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Complete list of publications with foreign collaborators (indicating your status as author):
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List of papers published in Conferences /Symposia/ Seminars, etc:
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List of the most outstanding Technical Reports/ Review Articles:
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Statement regarding collaboration with scientists abroad:
List of Patents taken
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Total number of patents granted in last five years.
Details of Books published:
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Contact Details


  • Centre for Nano Science and Engineering
    Indian Institute of Science
    C V Raman Road
    Bengaluru - 560012
    Karnataka
  • 080-22932442
  • 080-23604656
  • ambarish[at]iisc[dot]ac[dot]in
11 Dec 2018, http://ssbprize.gov.in/Content/Detail.aspx?AID=546