Monday, 28 May 2018

Artificial Membrane Inspired By Fish Scales May Help In Cleaning Oil Spills

IIT Guwahati based researchers have developed a stretchable underwater superoleophobic membrane that can separate water from various forms of oil contamination.


(Dr. Uttam Manna and Dibyangana Parbat )

Fish scales have a typical structure and chemistry that makes them naturally capable of repelling oil. Scientists are trying to exploit this property to develop novel materials that can find application in addressing oil pollution. The objective is to synthesise artificial interfaces that have oil-repelling properties or underwater superoleophobicity.

In this direction, a group of researchers at the Indian Institute of Technology (IIT), Guwahati, have developed a stretchable underwater superoleophobic membrane that can separate water from various forms of oil contamination. The membrane can work in complex scenarios, including extreme pH and temperatures, surfactant-contaminated water, river water, and seawater. It is able to separate oil repetitively from water even after 1,000 cycles of physical deformations.

The material has been designed by depositing a polymeric nano-complex on a polyurethane-based stretchable fibrous substrate. The polymeric nano-complex was prepared by mixing a branched polyethylene polymer with penta-acrylate molecules. The polymeric nano-complex coated fibrous substrate was then modified with glucamine molecules to mimic fish-scale wettability, explained Dr. Uttam Manna, leader of the research team, while speaking to India Science Wire.

Dibyangana Parbat, co-researcher, said the new material could help in taking care of wastewater discharge from refineries and other oil-based industrial units and accidental oil spills. In addition, it could also have biomedical applications. For instance, it could be used as an anti-biofouling coating on substrates such as catheter balloons.

The existing general approaches for synthesis of fish-scale mimicked interfaces are mostly based on depositions of polymeric hydrogels and metal oxides, both of which are not durable in severe conditions.

“This work can find immense applications, and potentially create economic value,” commented,” Dr. Thalappil Pradeep, Professor of Chemistry, from the Indian Institute of Technology Madras, who was not connected with the study.

This study was financially supported by Science and Engineering Research Board (SERB), Department of Science and Technology. The results of this study have been published in Journal of Materials Chemistry A.

Journal ref.: 

Wednesday, 23 May 2018

Scientist Uncover A Piece In The Puzzle Of Macrophage Activation

Scientists at the Institute of Microbial Technology (IMTECH), Chandigarh have found that a protein called Arf-like (Arl) GTPase-11(Arl11) activates macrophages in response to pathogenic stimuli.




(Scientists at the Institute of Microbial Technology (IMTECH), Chandigarh)


Macrophages - derived from the Greek word meaning large eaters’ - are one of the sentinels of human immune system that engulf pathogens and degrade them and also alert other sentinels about presence of foreign pathogens. However, in some cases there is uncontrolled or hyperactivation of macrophages such as in cancer or autoimmune disorders.

Researchers are trying to shed light on how macrophages get activated so as to help control such problems. Scientists at the Institute of Microbial Technology (IMTECH), Chandigarh have found that a protein called Arf-like (Arl) GTPase-11(Arl11) activates macrophages in response to pathogenic stimuli. In a paper published in Journal of Biological Chemistry, they have reported that the protein is essential for macrophages to kill foreign pathogens.

"We worked on this particular protein as previous studies had found it to be missing in tumour cells but its function was not known. We were surprised to know that it is expressed in many immune cells including macrophages, and therefore set out to know what would be the function of Arl11 in macrophages," Dr. Amit Tuli, who led the research team, told India Science Wire.

The study throws light on cellular function of Arl11, which is an evolutionarily conserved protein. "We found that the expression of Arl11 increases when macrophages encounter pathogens and that this is required to initiate a cascade of events that finally result in activation of macrophage," explained Subhash B. Arya, a member of the research team.

Understanding how immune system functions is crucial not only for immunotherapy, such as, against cancer but also to understand inflammation that damages normal tissues. The study found that by increasing Arl11 expression in macrophages can activate them. "It will be highly relevant to study Arl11 expression changes in diseases such as autoimmune disorders, atherosclerosis and obesity", added Dr. Tuli.

Commenting on the work, Prof. Somdatta Sinha from Indian Institute of Science Education and Research (IISER), Mohali, who was not associated with the study, said, "the study has found a novel and interesting relation between a gene that is known to be related to familial risk of different types of cancers, to its role in responding to bacterial pathogen in certain immune cells. The molecular elucidation of pathways of interactions of this gene can, in the long run, tell us ways that immune system functions in handling different types of diseases."

The research team included Subhash B. Arya, Gaurav Kumar, Harmeet Kaur and Amandeep Kaur. This work was supported by the Wellcome Trust/Department of Biotechnology (DBT) India Alliance and CSIR-IMTECH intramural funding.

Journal reference: 

Wednesday, 16 May 2018

Metal-Organic Nanosheets May Help Develop Novel Lens Material

The new photochromic 2D metal-organic nanosheets (MONs) are envisaged to be applicable not only in ophthalmic lenses, but also in other related applications, where light-induced switching between two or more species with different optical properties must occur smoothly.



(Prof. J.N. Moorthy and his team members)

Photochromic materials can change colour under stimulation of light. They are of high commercial importance for ophthalmic lens industry as also in sectors like optoelectronic switching devices, data storage and optical transmission.

Photochromic materials change colours on account of changes in the arrangement of atoms in materials. Atoms in photochromic materials are arranged in a certain manner and change when exposed to sunlight or UV light. We can observe this reversible behaviour in sunglasses. However, there are challenges associated with polymers. It is restricted by what features are desired in polymers in terms of rigidity, hardness and scratch resistance. Presently, researchers achieve photoswitching by linking photochromes covalently to soft low-molecular weight polymers.

A team of researchers at Indian Institute of Technology (IIT), Kanpur have demonstrated that porous 2-dimensional metal-organic nanosheets (MONs) constructed from photochromic building blocks can also be employed as agents or dopants in polymers to bring out the desired optical properties in photochromic polymers.

Three dimensional porous metal-organic framework materials (MOFs) have been used for various applications like photo-controlled gas storage, separations, sensing, and catalysis in recent years. However, they are not suitable for use in thin films and polymeric matrices to develop photo-responsive materials, as they pose problems like leaching and poor photoswitching.

The new photochromic 2D metal-organic nanosheets (MONs) are envisaged to be applicable not only in ophthalmic lenses, but also in other related applications, where light-induced switching between two or more species with different optical properties must occur smoothly.

Speaking to India Science Wire, leader of the team Prof. J. N. Moorthy said, “Photo-responsive MONs can find applications in ophthalmic industry. As photo-chromes distributed in polymeric 2D nanosheets can be impregnated in rigid polymeric matrices, leaching of photo-chromes can be overcome, besides providing practical simplicity in terms of fabrication. The concept can also be exploited for photo-controlled sieving of organic molecules.”

Commenting on the work, Prof. Rahul Banerjee from Indian Institute of Science Education and Research (IISER), Kolkata, who was not involved in this study, said, “this is an interesting finding in which researchers could show that exfoliation of layered porous metal-organic frameworks (MOFs) using a top-down approach can help produce 2D metal-organic nanosheets (MONs). This type of crystal engineering approach is quite novel and could bring in novel and new applications in the field of MOFs.”

Prof. Gautam R. Desiraju, Indian Institute of Science, Bangalore, who too was not involved in the study, said, “MOFs as a field is getting saturated and plateauing out. It may require a new vision over the next five to ten years. This subject is not associated with organic chemistry alone. Multi-disciplinary study of MOFs may move in advantageous directions in the future. Chemistry is looking for new paradigms, where the essence of the old is clubbed with a whole new superstructure, combining vertical and horizontal ways of thinking.”

The study has been published in the latest issue of journal CHEM. Besides Prof. Moorthy, the research team included Arindam Mukhopadhyay, Vijay Kumar Maka, and Govardhan Savitha. The study was funded by Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST).

Reference: Photochromic 2D Metal-Organic Framework Nanosheets (MONs): Design, Synthesis, and Functional MON-Ormosil Composite

Wednesday, 9 May 2018

Scientists Find Synthetic Mimic For Critical Biomolecule

The researchers have mimicked ATP-selective actin- like self-assembly in the laboratory very similar to what happens in the natural conditions inside the cells.





(The research team at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru.)

Biological assemblies are thousands of tiny pieces of machinery which play collectively important roles towards maintaining the cellular structure and functions, and many of them even play very critical roles. Self-assembly of these tiny machines requires biological fuel to become operational. Scientists have been trying to figure out how these tiny machines are controlled. This could help in controlling engineered organic designs comparable to natural frameworks.

A research team led by Dr. Subi J. George and Dr. S. Balasubramanian at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, have shown that synthetic molecules can grow and be controlled on similar stimuli such as biological systems.

In this study, researchers worked on Actin, a protein which frames the contractile fibers of muscle cells. In a living system, Actin assembles on its own using its monomer components under the influence of biological fuel Adenosine Triphosphate (ATP). Actin as the tiny machine works like a treadmill to support cellular movements.

The researchers have mimicked ATP-selective actin- like self-assembly in the laboratory very similar to what happens in the natural conditions inside the cells. They could observe monomer subunits undergoing ATP-fuel-driven elongation resembling natural actin self-assembly. Interestingly, when researchers used ATP-hydrolysing enzymes, it prompts actin dissociation. The results of this study have been published in the journal Nature Communications.

Speaking to India Science Wire, Dr. George said “since the stimulus in our case is ATP, which is one of the most universally present chemicals, this makes our work a benchmark in what can be achieved synthetically. Also, our study has come closest in synthetically mimicking natural protein Actin’s assembly, a protein which plays an important role in various biological functions. These outcomes will guide investigators to search for more synthetic analogs of important biological self-assembly”.

“Using biological cues like ATP opens up routes for bio-adaptable systems. A step even further perhaps is the possibility of an organic electronic device in the interface with biological live feed. Such a system would be highly efficient and uniquely adaptive in reporting live biological changes in a body,” he added.

Commenting on the research findings, Prof. E. W. Meijer from the Eindhoven University of Technology, The Netherlands- who is not involved in the work, said, “Researchers have tackled one of the main challenges in mimicking natural systems. Where chemists normally can control the assembly of small molecules in large one-dimensional aggregates only by solvent or temperature, Nature assembles and disassembles these structures by chemical fuels – chemical reactions that take care of the growth. This study is an important next step in the development of functional life-like materials and systems.”

The research team also included Ananya Mishra, D. B. Korlepara, Mohit Kumar, Ankit Jain, N.Jonnalagadda, and K.K. Bejagam. The study was funded by the Department of Science and Technology.

Reference:
Biomimetic temporal self-assembly via fuel-driven controlled supramolecular polymerization