TIFR
Department of Chemical Sciences
School of Natural Sciences

Calender

May 1, 2019 at 2.30 pm in AG-69

Title :

Buoyant Microcapsules: Simple motility to Complex Autonomous Behavior

Abstract :

Nature has always been a great source of inspiration for the design of artificial materials with improved hierarchical organization, superior properties and smart functions. In this age of artificial intelligence and smart systems, chemists are increasingly looking to design active and adaptive materials taking inspiration from the various biological processes and their self-regulatory mechanisms which make ‘life’ possible. In this talk, I will illustrate with an example of a microcapsule with an entrapped gas bubble whose motility is governed by buoyancy forces, how we can design complex autonomous behavior into relatively simple systems. Our results show that microcapsules can be propelled by an active control of buoyancy forces and this buoyant motility can be used to trigger chemical reactions, simulate self-sorting behavior in microcapsule communities and achieve complex oscillatory motility.

References:

  1. B. A. Grzybowski & W. T. S. Huck, The Nanotechnology of Life-inspired Systems, Nat. Nanotechnol. 2016, 11, 585.
  2. B. V. V. S. P. Kumar, A. J. Patil & S. Mann, Enzyme-powered motility in buoyant organoclay/DNA protocells, Nat. Chem. 2018, 10, 1154.
  3. L. Rodriguez-Arco, B. V. V. S. P. Kumar, M. Li, A. J. Patil & S. Mann, Modulation of Higher-order Behaviour in Model Protocell Communities by Artificial Phagocytosis, Angew. Chem. Int. Ed. 2019, DOI: 10.1002/ange.201901469.

 

 

April 30, 2019 at 2.30 pm in AG-69

Title :

Advancement of Nanomaterials: Nanotherapeutics and Antibacterial Performance

Abstract :

       Carbon nanomaterials are promising in nature due to their higher surface area, known chemistry and ease of structural functionalization. A higher surface area and modulation of functionalities is the key to success to extend their potential in various domains. Present chemistry of graphene oxide (GO) synthesis is dominated by Hummer’s method and its modified versions. The non-reproducibility, variation in sources and physical reaction parameters affect size, degree of oxidation, nature, and type of oxo-functionalities. Furthermore, problems associated with its mass production demands development of better and easier synthetic protocols. In our lab, we are exploring safer, easier, less-energy intensive protocols for synthesis of GO and their advancement in biomedical applications.

       Nanotherapeutics is most appealing and viable approach to enhance the potential of existing drugs rather than designing and synthesizing new drug molecules to counter diseases. More recently, gene-based antitumor therapy demands smart engineering of effective vectors.

In this respect, we have explored biocompatible polymers tethered GO nanoconjugates as efficient nonviral vectors for gene-based cancer therapeutics. A promisable transfection and gene-knock down efficiency is revealed and results were compared with commercial vector. A pH-triggered release of siRNA from the vector-siRNA complex was studied to provide a mechanistic insight toward unloading of siRNA from the vector.

       In another work, enhancement in efficacy of traditional medicine with non-toxic surface modified metal oxide nanoparticles is explored. The nanoparticles are specially designed to allow sustained release of bound species to facilitate prolonged activity of drug.

 

       Additionally, pristine GO coatings synthesized from different routes revealed remarkable antimicrobial activity due to its specific surface-interface interactions with the bacteria, which is again a valuable addition at biomedical frontiers.

 

April 25, 2019 at 4.00 pm in AG-80

Title :

Fluorescent Red Emitting Sensors for Imaging Signal Mediating Phospholipids

April 22, 2019 at 4.00 pm in AG-69

Title :

Predicting directional flexibility of protein from its crystal structure

Abstract :

Mechanical flexibility is found to be anisotropic in protein molecules. In order to understand complex role of protein in mechano-biology or develop new allosteric protein based nano-materials, anisotropic response of protein to uniaxial mechanical stress is needed to be understood in detail. In this talk I will propose an analytical framework to compute directional flexibility in terms of directional spring constant of proteins from its native state crystal structure. Our formalism includes Cα atom based coarse-grained Elastic Network Model (ENM) where we employed statistical propagation of error to obtain variance of a distance between two atoms from standard deviation of coordinates of the constituent atoms using ENM normal modes. Directional flexibility of Ubiquitin predicted in this way is almost ~ 70% accurate in comparison to that obtained from all atom explicit solvent Molecular Dynamics simulation. I will also discuss about tuning ENM potential to get better agreement on directional flexibility prediction. 

April 18, 2019 at 4.00 pm in AG-80

Title :

Amorphous Zeolitic Nanosponges as Heterogeneous Solid Catalysts

April 15, 2019 at 4.00 pm in AG-69

Title :

Towards understanding the structure of amyloids in the lipid membrane

April 12, 2019 at 2.30 pm in AG-69

Title :

A new GC Binder for Sequence-selective DNA Recognition

Abstract :

Click here

 

April 11, 2019 at 4.00 pm in AG-80

Title :

Elucidating Folding-Unfolding Pathways of Ubiquitin Family Proteins

April 9, 2019 at 2.30 pm in AG-69

Title :

Online Electrochemical Mass Spectrometry as A Tool to De-Convolute Catalysis, Instability and Efficacy of Protection Strategies

Abstract :

Limited stability of most electrode materials (EM) and electrolytes under stringent operating conditions is a matter of concern for the battery research community and industry. In past few years, it has been demonstrated that EMs degrade through their reactive interface with the electrolyte. Undesirable interfacial reactions result in formation of solid precipitates that impede the charge transfer and can serve as an active site for electrolyte consumption, anode corrosion and passivation, thereby, leading to inefficient lithium/sodium ion and metal-O2 batteries (LIB/SIB/LOB). Especially, the progress of high energy and high voltage batteries is mostly restricted by issues associated with the electrode/electrolyte interfacial instability and electro-chemomechanical degradation under the operation conditions. As a result, strategies that (1) stabilize the interface by designing a protection layer commonly known as “artificial solid electrolyte interface (ASEI)” and (2) that can electro/chemically catalyse the reactions and bring the potentials to lower values can significantly enhance battery performance by stabilizing the functional interface and addressing the deleterious reactions between electrode and electrolyte. Nevertheless, there is a dire need of in-operando and in-situ analytical tools to deconvolute the degradation paths to have targeted solutions based on the instability of the components. Online electrochemical mass spectrometry in synergy with solid state NMR can prove to be on such tool. 

April 8, 2019 at 4.00 pm in AG-69

Title :

Understanding the mechanism of binding between proteins in CDK1/cyclin-B/CKS-2 complex

April 4, 2019 at 4.00 pm in AG-80

Title :

Probing Singlet Fission on all-trans Lycopene Aggregates

April 2, 2019 at 2.30 pm in AG-80

Title : 

Computational Descriptions of Bis-terpyridine Based Molecular Breadboard Circuits and their Single-Molecule Break Junction Conductance

April 1, 2019 at 4.00 pm in AG-69

Title :

Designing Protein-Specific Folding Catalysts

March 28, 2019 at 2.30 pm in D-406

Title :

Design and Synthesis of Conjugated Molecules for Band Gap Engineering and Photostability of OPVs

Abstract :

             Organic photovoltaic (OPV) modules are flexible, light weight, transparent and thin compared to other emerging photovoltaic technologies, making them well-suited for applications ranging from solar windows to fabrics. A large number of polymer semiconducting materials of Donor-Acceptor–Donor (D-A-D) architecture have been synthesized and used in OPV devices in recent times reaching remarkable power conversion efficiencies up to 15%. However, the diversity of monomeric units and the numerous available reports in the structural complexity of D-A-D conjugated p-type polymers indicate that there is scope for new materials which can further improve the performance of OPV devices based on D-A-D polymers. In this seminar presentation, I will discuss briefly about my Ph.D. thesis work. The first part of work explores structural level architecturing of conjugated small molecules and polymers to modify the performance of the OPVs. Demonstrate the effect of molecular level modification on frontier molecular energy levels, planarity, absorption spectra and device performance. 

             Additional to the development in power conversion efficiency of the OPVs, the cost of large area OPV device manufacture continues to decrease with improvements in roll-to-roll manufacturing processes. However, while these advances in efficiency and cost will ultimately the key to the success of the technology, the long term stability of OPV devices under illumination still remains an obstacle to their industrial viability. While the thermal and oxidative-stability of contacts and interfaces in an OPV device can contribute to a decrease in its performance with time, a leading contributor to device decay is photo-oxidation of the active layer itself. 

 

             Hence in the second part of the work, a series of chalcogen based polymers have been synthesized and the photostability of the unencapsulated active layers and the device life time has been monitored over a period of time. The thesis work has further investigated the photostability of several combinations of fluorinated and non-fluorinated high-performance donor polymers with both traditional and fluorinated fullerenes. The miscibility of the active layer component is probed with time-resolved photoluminescence (TRPL). The miscibility of the polymers and the fluorinated fullerenes were improved by the strategic fluorination of the polymers, by new synthesis routes. These results ultimately suggest that appropriate fluorination strategies applied to both the donor and acceptor can be a viable route toward a new model of intrinsically photo- and phase-stable OPV active layers.

 

March 25, 2019 at 4.00 pm in AG-69

Title :

Fluorescent Sensors for Imaging Signal Mediating Phospholipids