Today, we see great innovations and unforeseen interventions in the area of medical sciences and healthcare – whether these are low-cost sanitary napkins or highly sophisticated implants. The research community have even ventured into producing organs and artificial meat in the lab. And it won’t be wrong to say that materials development has contributed immensely to this disruptive development. Recently, I was reading about nicotine patches which basically function to satisfy the urges of mind and body, while avoiding the adverse effects of smoking. Transdermal patches like these also have one particular advantage, that is it reduces the need for frequent dosing, causes lesser systemic side effects and offer overall good patient compliance. Of course, bringing something like this to the market involves two things: one to make such interventions possible technologically and second cost optimisation to make it accessible to the people.
Ever since I graduated from Cambridge and came back to India, I have been interested to contribute in the health care space especially in areas relevant to the Indian community through the intervention of material science. My colleague Dr. Chandra Shekhar Sharma, at IIT Hyderabad and I had a collaboration with Prof. Stephen Eichhorn at the University of Exeter under the DST-UKIERI grant to develop patterned electrospunfabric for energy, environment and healthcare. The material used for this work was cellulose acetate. The work led to the development of an interesting technology and material. The idea for patterning derives inspiration from nature – the lotus leaf, the salvinia leaf, the rose petal – all of these are superhydrophobic or water repelling, primarily, due to the nanostructures or patterns. Hence, we set out on the journey to tune wettability by patterning or changing roughness.We have been successful in developing a regular patterned nanofibrous fabric by electrospinning in a single step. Another query that I should perhaps answer is ‘why electrospinning’? Electrospinning is a beautiful technique that can produce sub-micron fibrous non-woven fabric under the influence of electric field. This technique offers immense tunability on material parameters such as fibre dimensions, density thickness of fabric and so on. Smaller dimensions imply higher surface to volume to ratio and hence high functionality.
The idea for patterning derives inspiration from nature – the lotus leaf, the salvinia leaf, the rose petal – all of these are superhydrophobic or water repelling, primarily, due to the nanostructures or patterns.
Patterned electrospun fabric was obtained by adding nylon mesh of different mesh size on the collector which connected to ground. Nylon being a dielectric gets polarised in an electric field and hence attracts cellulose acetate fibres on its self. Hence, we had a patterned nanofibrous fabric with different contact angles for the different mesh size of nylon mesh used.
Generally, this as-spun non patterned fabric is hydrophilic in nature. However, when electrospinning was carried out through non-conducting templates, viz nylon meshes with 50 and 100 μm size openings, two kinds of hydrophobic micro-patterned CA nano fabrics were produced. Porosity, nanofibrous nature and tunable wettability led to the application as transdermal patch. We chose a common painkiller – diclofenac – and incorporated in the material. In vitro transdermal testing of our nanofibrous mats showed promising results. Further, we could obtain a zero order sustained drug release up to 12 h for the transdermal system. Sustained release and prevention of burst release for low half-life drugs like Diclofenac sodium is crucial to prevent drug related toxicity.
Further, we are focussing on incorporating antimicrobials from herbs as they are bound to play an important role given the increasing problem of antimicrobial resistance. Age old home method of fighting fungal infection is usage of Ajwain/caraway fumes, for example in post-delivery care. In fact, the same thing is used to prevent microbial decay of paper in form of Thymol fumigation.
Further, we are focussing on incorporating antimicrobials from herbs as they are bound to play an important role given the increasing problem of antimicrobial resistance.
In parallel, we are working on a material derived from bacteria. In our lab, we ferment sugar-rich medium, like fruit juices and sugar-rich tea, beer, to obtain cellulose. This cellulose because is produced by benchtop culture and therefore gives enough opportunity to tune the material. Cellulose otherwise is obtained from plants and trees, after a lot of chemical treatment. Bacterial cellulose is a green material as it can be synthesised from agricultural wastes, fruits and vegetables and does not involve any harsh chemical process or deforestation as involved in cellulose extraction. This material is similar to the electrospun nanofibrous fabric. We were able to design a material which was able to preserve tomato for 34 days as against polypropylene microporous packaging material used by leading fruit and vegetable delivery online store, which preserved for 15 days. We are now testing the utility of this material in personal hygiene space. In spite of being well educated and working in clean places, I have been constantly bothered by vaginal candidiasis. This forced me to read online and it surprised me to know that a large fraction of women belonging to all strata of society suffer from this. I have decided to find a solution, if not curative, at least preventive. My group is currently trying to make liners for regular usage based on herbal oils. Preliminary study has been completed. The substrate material is again the same microbe-derived material used for food packaging.
Overall we believe that materials are making a breakthrough in healthcare, given the right perspective and focus.
