IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Today single cell research is a great interest to analyze cell to cell or cell to environment behavior with their intracellular compounds, where bulk measurement can provide average value. To deliver biomolecules precise and localized way into single living cell with high transfection rate and high cell viability is a challenging and promisible task for biological and therapeutic research. In this report, we present a nano-localized single cell nano-electroporation technique, where electroporation take place in a very precise and localized area on a single cell membrane to achieve high efficient delivery with high cell viability. We fabricated 60nm gap with 40 nm triangular Indium Tin Oxide (ITO) based nano-eletcrode tip, which can intense electric field in a nano-localized area of a single cell to permeabilize cell membrane and deliver exogenous biomolecules from outside to inside of the cell. This device successfully deliver dyes, proteins into single cell with high cell viability (98%). The process not only control precise delivery mechanism into single cell with membrane reversibility, but also it can provide special, temporal and qualitative dosage control, which might be beneficial for therapeutic and biological cell studies. © 2014 IEEE.

Department of Engineering Design

World University root node

9th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, IEEE-NEMS 2014

Nanolocalized single cell membrane nanoelectroporation

The Special Issue of Micromachines entitled “Micro/Nanofluidic Devices for Single Cell Analysis” covers recent advancements regarding the analysis of single cells by different microfluidic approaches. To understand cell to cell behavior with their organelles and their intracellular biochemical effect, single cell analysis (SCA) can provide much more detailed information from small groups of cells or even single cells, compared to conventional approaches, which only provide ensemble-average information of millions of cells together. Earlier reviews provided single cell analysis using different approaches [1–3]. The author demonstrates invasive and noninvasive with time and non-time resolved SCA [1]; whereas some other literature provided destructive (with dyes, DNA, RNA, proteins and amino acids) and nondestructive (electroporation, impedance measurement and fluorescence based methods) cellular content analysis using microfluidic devices [3]. Further literature also suggest that single cell analysis is possible with capillary electrophoresis (CE) combined with a detection method such as electrochemical detection (ED), laser induced fluorescence (LIF) detection and mass spectrometry (MS) [4,5].&nbsp;

Fulltext

Micromachines

Micro/nanofluidic devices for single cell analysis

Interaction of electric field with biological cells is an important phenomenon for field induced drug delivery system. We demonstrate a selective and localized single cell nano-electroporation (LSCNEP) by applying an intense electric field on a submicron region of the single cell membrane, which can effectively allow high efficient molecular delivery but low cell damage. The delivery rate is controlled by adjusting transmembrane potential and manipulating membrane status. Thermal and ionic influences are deteriorated from the cell membrane by dielectric passivation. Either reversible or irreversible by LSCNEP can fully controlled with potential applications in medical diagnostics and biological studies. © 2013 AIP Publishing LLC.

Applied Physics Letters

Tuning nano electric field to affect restrictive membrane area on localized single cell nano-electroporation

Single cell analysis is potentially beneficial to understand cell to cell behavior with their intracellular compounds from population of millions of cells together. We demonstrate an efficient and fast method for multi-localized single cell electroporation, where electroporation take place with multiple positions together at a tens nanometer confined region on single cell membrane by using ITO nano-electrode arrays. In this study, we successfully deliver dyes and protein into single cell with different field strengths and pulse durations. This new approach can allow to analyze different dyes/molecules interaction in single cell which potentially applicable for medical diagnostics and biological studies.

17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013

Nano-intensified electric field for multi-localized single cell electroporation

The behaviors of cell to cell or cell to environment with their organelles and their intracellular physical or biochemical effects are still not fully understood. Analyzing millions of cells together cannot provide detailed information, such as cell proliferation, differentiation or different responses to external stimuli and intracellular reaction. Thus, single cell level research is becoming a pioneering research area that unveils the interaction details in high temporal and spatial resolution among cells. To analyze the cellular function, single cell electroporation can be conducted by employing a miniaturized device, whose dimension should be similar to that of a single cell. Micro/nanofluidic devices can fulfill this requirement for single cell electroporation. This device is not only useful for cell lysis, cell to cell fusion or separation, insertion of drug, DNA and antibodies inside single cell, but also it can control biochemical, electrical and mechanical parameters using electroporation technique. This device provides better performance such as high transfection efficiency, high cell viability, lower Joule heating effect, less sample contamination, lower toxicity during electroporation experiment when compared to bulk electroporation process. In addition, single organelles within a cell can be analyzed selectively by reducing the electrode size and gap at nanoscale level. This advanced technique can deliver (in/out) biomolecules precisely through a small membrane area (micro to nanoscale area) of the single cell, known as localized single cell membrane electroporation (LSCMEP). These articles emphasize the recent progress in micro/nanofluidic single cell electroporation, which is potentially beneficial for high-efficient therapeutic and delivery applications or understanding cell to cell interaction. © 2013 by the authors.

Recent trends on micro/nanofluidic single cell electroporation

Despite the significant research in electroporation, high electric field was applied to the whole cells resulted in permeabilizing the membrane of millions of cells without reversibility [1]. To deliver biomolecules through the specific region of the cell membrane with high cell viability and high transfection rate is important for various biological and therapeutic applications.This report presents a new type localized single cell membrane electroporation (LSCMEP), at specific region of the single cell withthe application of 800 μs electric pulse. The ITO nano-electrodes with 100nm thickness and 500 nm gap between two electrodes can generate an intense electric field to track biomolecules inside HeLa cell in our studies. This small gap between two nano-electrodes can neglect thermal effect on cell membrane and permit reversible electroporation with high cell viability (90%) and minimum effected electroporation region (0.48 μm). Our approach successfully delivers biomolecules through a specific region of single cell with high transfection rate (82%) and high cell viability. This process, not only generates well-controlled nano-pores allowing rapid recovery of cell membrane, but also it provides a clear optical path potentially tracking of drugs to deliver inside single cell. © 2013 IEEE.

8th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, IEEE NEMS 2013

Nanofocused electric field for localized single cell nanoelectroporation with membrane reversibility

Diamond-like nanocomposite (DLN) thin films were deposited on pyrex glass substrate using different flow rate of haxamethyldisiloxane (HMDSO) based liquid precursor with nitrogen gas as a glow discharged decomposition by plasma enhanced chemical vapor deposition (PECVD) technique. The significant influence of different precursor flow rates on refractive index and thickness of the DLN films was measured by using spectroscopic filmatrics and DEKTAK profilometer. Optical transparency of the DLN thin films was analyzed by UV-VIS-NIR spectrometer. FTIR spectroscopy, provides the information about shifted bonds like SiC2, Si-C, Si-O, C-C, Si-H, C-H, N-H, and O-H with different precursor flow rate. We have estimated the hardness of the DLN films from Raman spectroscopy using Gaussian deconvolution method and tried to investigate the correlation between hardness, refractive index and thickness of the films with different precursor flow rates. The composition and surface morphology of the DLN films were investigated by X-ray photo electron spectroscopy (XPS) and atomic force microscopy (AFM) respectively. We have analyzed the hardness by intensity ratio (ID/IG) of D and G peaks and correlates with hardness measurement by nanoindentation test where hardness increases from 27.8 μl/min to 80.6μl/min and then decreases with increase of flow rate from 80.6μl/min to 149.5μl/min. Finally, we correlates different parameters of structural, optical and tribological properties like film-thickness, refractive index, light transmission, hardness, surface roughness, modulus of elasticity, contact angle etc. with different precursor flow rates of DLN films. Copyright © 2012 Author(s).

AIP Advances

Influence of flow rate on different properties of diamond-like nanocomposite thin films grown by PECVD

In recent years, more studies focused on single cell electroporation. However, not only the position cannot be confined in the specific region of the cells, but also the employed electrodes are not transparent, causing difficulty on optical observation. Here, we demonstrated localized single cell membrane electroporation (LSCMEP), which an efficient to deliver drugs into single cell by selective and localized way from millions of cells. The ITO microelectrodes fabricated by wet etching as well as FIB technique, which successfully deployed 1μm gap between two microelectrodes. Due to submicron level gap, electric field can more intense in a narrow region. The diffusion mechanism with PI dye intensity variation has been analyzed by image pro plus software. In our approach, we have successfully achieved 0.99 μm electroporation regions on the cell membrane to inject PI dye into the cell with high cell viability by trypan blue test. We demonstrated the cell self-recover process from the injected PI dye intensity variation. Our localized single cell membrane electroporation technique, not only generates well-controlled nano-pore allowing rapid recovery of cell membrane, but also provides a clear optical path potentially monitoring drug/DNA delivered into single cell level even in single molecule level.

Proceedings of the 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012

Electrically mediated gene delivery and their diffusion mechanism on localized single cell using ITO microelectrode based transparent chip

Single cell electroporation is one of the nonviral method which successfully allows transfection of exogenous macromolecules into individual living cell. We present localized cell membrane electroporation at single-cell level by using indium tin oxide (ITO) based transparent microelectrodes chip with inverted microscope. A focused ion beam (FIB) technique has been successfully deployed to fabricate transparent ITO micro-electrodes with submicron gaps, which can generate more intense electric field to produce very localized cell membrane electroporation. In our approach, we have successfully achieved 0.93 μm or smaller electroporation region on the cell surface to inject PI (Propidium Iodide) dye into the cell with 60 % cell viability. This experiments successfully demonstrate the cell self-recover process from the injected PI dye intensity variation. Our localized cell membrane electroporation technique (LSCMEP) not only generates reversible electroporation process but also it provides a clear optical path for potentially monitoring/tracking of drugs to deliver in single cell level. © Springer Science+Business Media, LLC 2012.

Biomedical Microdevices

Delivery of molecules into cells using localized single cell electroporation on ITO micro-electrode based transparent chip

Diamond-like nanocomposite (DLN) thin films are deposited on glass (pyrex/silicon) substrate by plasma enhanced chemical vapor deposition (PECVD) technique using different combinations of hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDSN) gas precursors. The surface morphology of the DLN films has been investigated by atomic force microscopy (AFM). Nanoparticles on DLN films were analyzed by highresolution transmission electron microscopy (HRTEM). DLN films contain Si 3N 4, SiC and SiO x nanoparticles (sizes ~ 6-30 nm) within amorphous matrix which reduce the compressive stress of the films and increase the adhesiveness between the films and substrates. The biocompatibility of the films is verified using cell adhesion and morphology studies of the DLN films. We have also observed the fluorescence emission from the nanoparticles of the films. The biocompatibility of DLN films is examined by the cell viability test. This article emphasizes on the possible biomedical applications of prepared films like biosensors for diagnostics and therapies, surgical instruments, prosthetic replacements etc. Chemically modified DLN surface can be act as a sensing trace of gases to detect biomolecules in biological research. © 2012 by American Scientific Publishers.

Science of Advanced Materials

Biomedical applications of diamond-like nanocomposite thin films

The structural and tribological properties of diamond-like nanocomposite (DLN) thin films, deposited by radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) on the pyrex glass or silicon substrate using the combinations of siloxane and silazane based gas precursors, are discussed. High resolution transmission electron microscopy (HRTEM) result shows the DLN film structure with different nanoparticle size. The surface morphology of the DLN films has been investigated by using atomic force microscopy (AFM). The structural properties of the DLN films are analyzed by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). We have observed different bonds like C-C, C-H, C-Si, C-O, Si-O, Si-H, etc. in the DLN films by XPS and FTIR analysis, which reveal that it consists of a-C:H and a-Si:O networks. The disorder and graphitic structure of amorphous carbon of the deposited films are analyzed by Raman spectroscopy. The hardness and friction coefficient of the films are measured by nanoindentation and scratch test techniques. Finally, we find that mixed siloxane and silazane precursor (MSSP) based DLN films provide better film-properties like surface roughness, friction coefficient, etc. than those of single siloxane or silazane precursor (SSSP) based DLN films. © 2011 Elsevier B.V.

Surface and Coatings Technology

Structural and tribological properties of diamond-like nanocomposite thin films

Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of C-C, C-H, Si-C, and Si-H bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio ID/IG. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS). © 2010 American Institute of Physics.