Research Domains

Prof. Gupta has been working on the various scientific research domains in biomedical applications. His keen interest lies in tissue engineering and biomaterials.

Polymer Functionalization

Polymers are the backbone of biomedical technology. The polymers do not have required features for their application in bio and medical fields. This is where the selective modification of the biomaterial is needed. Following are the approaches for our ongoing functionalization technology towards the biomaterial development. The inherent vision of polymer functionalization is to introduce specific properties such as biocompatibility, bioreceptivity and biointeraction.

Radiation Grafting: The radiation grafting is one of the most interesting techniques where a monomer is polymerized onto the pre-existing polymer. As a result, a branched structure is formed. By virtue of the grafted branches, selective modification of the polymer is achieved while the inherent properties of the material are retained. We have been developing polymers by graft polymerization of monomers such as methacrylic acid and N-vinyl pyrrolidone onto polyester. The fabrication of a thermosensitive textile based on gamma ray induced graft copolymerization of acrylic acid and N-isopropyl acrylamide on polypropylene nonwoven fabric as a base material is being carried out, which will be used for transdermal drug delivery.


Schematic representation of the grafting process

Plasma Grafting: Plasma treatment of polymer surfaces is being used to carry out nanoscale changes on the surface. The surface chemistry is being modified by using different gases in such a way that desired functional groups are created. In a more advanced stage, the plasma activated surface is being grafted with different monomers so that a biocompatible and bioreceptive surface may be developed. The plasma activation is being used to develop materials for bioimmobilization and biocompatibility with the biological system.

        
Plasma Functionalized PP filament


Wound Dressing

The development of wound care systems is another area of the biotextile activities in the department. The aim of the present work is to develop wound dressings which are innovative in terms of the comfort and performance. The wound dressing activity has been going on in collaboration with Prof. M.S. Alam, Jamia Hamdard University at New Delhi. We have designed and developed wound dressing materials based on Polyvinylalcohol/ Polyethylene oxide (PVA/PEO) and herbal compounds so that the wound undergoes proper healing where scar formation is the minimum.


Antimicrobial Activity of Herbal Compound based dressing against E. Coli (ATCC11105), 1:106

Our recent efforts are to develop wound dressings based on pectin, gelatin hydrogels for enhanced wound healing. The incorporation of drugs into the dressings makes these dressings antimicrobial and help in control of infection around the wound. We have been able to produce a dressing which shows 98% scar prevention. Nanosoy reinforced dextran nanocomposite wound care membranes have been designed for scar free wound healing. Our subsequent studies are planned for the human trials very soon.


Scheme for the Modification of Pectin

We have also developed hydrogel wound care dressings based on Chitosan/PEG/PVP coated cotton fabric which have shown high porosity, good exudates absorption, air permeability and required tensile strength. Wound dressings composed of natural polymers chitosan and carboxymethyl cellulose have been developed. These blend membrane shows enhanced activities and provide an optimal environment condition for wound healing process.


Porous structure of the freeze dried textile based dressing

Animal test showing complete healing of wound using dressings
In recent studies, we have developed composite material for wound dressing containing nanosilver nanohydrogels (nSnH) of polymethacrylic acid along with Aloe vera and curcumin that promote antimicrobial nature, wound healing and infection control. Nanosilver nanogel coated cotton base dressings have been developed by very simple procedure for rapid and scar free healing. The dressings are smart and have been designed in such a way that they offer minimum pain during their removal from the wound site. The animal tests have been extremely interesting. The dressings are biocompatible and show minimum tissue reaction.

Acne treatment: In a joint project with Indian Council of Medical Research (ICMR), we developed biopolymer based hydrocolloid patches for acne treatment. Acne patches (containing pectin and essential oils) have been proved excellent efficacy against microbes like P. acnes and S. aureus which are responsible for causing Acne vulgaris.



Essential oil loaded hydrocolloid based anti-acne patches


Suture Materials

The recent efforts in our lab have been directed more in the area of Suture materials. The development of an antimicrobial suture based on nylon polypropylene, polyethylene and polyester monofilaments is being pursued by graft modification or plasma functionalization of the sutures since last ten years.


Antimicrobial polypropylene suture & suturing on mice model



The surface functionalization of the suture is carried out by plasma processing in such a way that the inherent characteristics, such as mechanical and knot strength of the suture are not affected. An antimicrobial drug is immobilized on the suture surface which is subsequently released into tissues surrounding the stitch and prevents the microbial invasion. The tissue compatibility of these sutures is excellent and no adverse reaction has been observed against these sutures.


Wound healing performance and histological studies of PET sutures

Four patents are filed and more than six publications are published on the development of PP, PE, PET and nylon based sutures and we are looking for the technology transfer in this area.


Smart Materials

The biomaterial activity is dedicated to the development of the Smart systems for drug delivery applications. We have been able to develop hydrogels by radiation induced copolymerization of various monomers with N-isopropyl acrylamide monomers into crosslinked structures. These materials offer excellent ability for the pH-sensitive or thermosensitive drug delivery in biological systems. The thermosensitive textile fabric has been developed which undergoes phase transition at 37.5ºC so that this patch can be used for the transdermal drug delivery systems.


Transdermal Drug Delivery Patch

Our group is working on the fabrication and characterization of a pH and temperature-sensitive textile for transdermal drug delivery, based on gamma ray induced graft copolymerization of acrylic acid/ N-isopropyl acrylamide on polypropylene nonwoven and polyester woven fabric as a base material. These patches undergo drug release at a temperature which is higher than 37°C leading to the smart drug delivery application.


Schematic representation of thermosensitive textile material

Recently, we are working new area of smart materials, we have been developed polyacrylic acid based self-healing hydrogels. Hydrogel shows efficient self-healing with in very short span of time with excellent tensile strength property.


Polyacrylic acid based self-healing hydrogels


Tissue Engineering

The Tissue Engineering is the most fascinating domain where an alternative to the existing transplantation approach has been visualized. The medical textile group has made significant progress in the development of scaffolds for human urinary bladder reconstruction and cardio-vascular scaffolds collaboration with the Swedish group.


Biocompatible knitting

E-SEM Morphology of Collagen-PET Knitting

The vision of the group is to move ahead towards the reconstruction of blood vessels for vascular Tissue engineering. We are specifically targeting the problems of Atherosclerosis and Aneurysm by designing biodegradable PCL based scaffolds including textile knitting and braiding of less than 6 mm diameter followed by cell seeding on these scaffolds. These scaffolds are bioreceptive and provide proper environment for the cell seeding.



PCL/PLCL blend based Braided Tubular scaffold

DBT India and European Union have provided significant encouragement in the area of blood vessel development based on textile structures. Under these Programmes, the copolymers have been successfully spun into filaments of 30-40 microns which are elastic in nature and can be fabricated into a braided structure. The idea is to create a blood vessel by immobilization of biomolecules and growing cells from the healthy blood vessel on both sides of the braided scaffold


PCL based Porous Scaffold

Endothelial cells on PCL Scaffolds

Cell culture studies on gelatin based electrospun mat for Vascular tissue engineering
In Joint project between IIT Delhi and SMIMS, Gangtok under NER-Twinning programme of DBT India have provided significant encouragement in the area of skin tissue engineering. Under this project, we used gelatin as a scaffolding material for skin tissue engineering with recent technique of electrospinning. The nanofibrous gelatin nanomats have been prepared and can be used viably as scaffolds for tissue engineering.



Cell culture studies of gelatin scaffold and proliferating keratinocyte cells

In observation the cell sheet formation is an innovative feature of the study. The confluent culture layered over the scaffold by day 3 demonstrates the ability of the electrospun gelatin scaffold to provide topographical cues necessary for contact guidance. The progressive proliferation of the cells on the scaffold as seen by day 3 implies that the electrospun nonwoven structure of the scaffold has a nanodimensional architecture that offers a large surface area that favored cell attachment.



Nanobiotechnology

Nanobiotechnology is the newest activity of our group at IIT Delhi. We have been interested in the preparation of the nanohydrogels where nanosilver may be generated in-situ. The approach is to prepare w/o nanoemulsions where the hydrophilic monomer represents the water phase. The non-polar solvent acts as the oil phase. The polymerization is assisted by gamma radiation and the reduction of silver proceeds during the polymerization stage.


Nanosilver within nanogel structure and treated E. coli

Size-controlled preparation of soy protein isolate nanoparticles (nanosoy) has been done by using nanoprecipitation method. Excellent control over protein aggregation was achieved, producing nanoparticles in the size range of 5–15 nm.


TEM images of nanosoya protein particles

The interest lies in the development of the functional nanogel which has the tendency to interact with the biomaterials surfaces and make them antimicrobial. The nanosilver gels prepared in our laboratory exhibit a number of properties that have not been seen before.