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Carbon xerogel nanoparticles were synthesized using repeated inverse emulsion polymerization of resorcinol-formaldehyde, followed by subcritical drying and pyrolysis at 1173 K. The prepared carbon xerogel nanoparticles were then structurally characterized by scanning electron microscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy and small angle X-ray scattering.Further, these carbon xerogel nanoparticles were tested for their electrochemical properties. Galvanostat charge/discharge experiments revealed a reversible capacity (400 mA h g À1 ) higher than that of graphite with excellent capacity retention and coulombic efficiency. Cyclic voltammetry and impedance spectroscopic studies were also carried out to support these findings. The remarkable electrochemical behaviour as exhibited by these carbon xerogel nanoparticles paves the way for their potential use as anode materials in lithium-ion battery.

Sustained release and prevention of burst release for low half-life drugs like Diclofenac sodium is crucial to prevent drug related toxicity. Electrospun nanofibers have emerged recently as potential carrier materials for controlled and sustained drug release. Here, we present a facile method to prevent burst release by tuning the surface wettability through template assisted micropatterning of drug loaded electrospun cellulose acetate (CA) nanofibers. A known amount of drug (Diclofenac sodium) was first mixed with CA and then electrospun in the form of a nanofabric. This as-spun network was hydrophilic in nature. However, when electrospinning was carried out through non-conducting templates, viz nylon mesh with 50 and 100μm size openings, two kinds 2 of hydrophobic micro-patterned CA nanofabrics were produced. In vitro transdermal testing of our nanofibrous mats was carried out; these tests were able to show that it would be possible to create a patch for transdermal drug release. Further our results show that with optimized micropatterned dimensions, a zero order sustained drug release of up to 12 h may be achieved for the transdermal system when compared to non-patterned samples. This patterning caused a change in the surface wettability, to a hydrophobic surface, resulting in a controlled diffusion of the hydrophilic drug. Patterning assisted in controlling the initial burst release, which is a significant finding especially for low half-life drugs.

Three-dimensional polymer nanofibrous mats with tunable wettability have been fabricated using a single step nonconductive template assisted electrospinning process. Cellulose acetate nanofibers are electrospun over a nylon mesh, which acts as the template. The as-deposited fiber mat is removed from this template to produce a free standing three-dimensional micropatterned nanofibrous mat. By simply varying the template mesh dimensions, the fraction of the air-liquid interface can be changed which allows control of the wetting mechanics. It is shown that the water contact angle can be varied from about 308 for a planar network to about 1408 for a patterned mat implying a complete transition from hydrophilic to hydrophobic behavior. Furthermore, upon stretching the fiber mat loses its pattern irreversibly and reducing the contact angle from 1408 to 1108 with increasing stretching.

It has been shown earlier that three-dimensional (3-D) electrode architecture facilitates higher energy and power density than the planar thin film based electrodes. In the present study, we fabricated SU-8 photoresist derived micro-patterned three-dimensional carbon-based electrodes using photolithography on stainless steel (SS) wafer used as a current collector. The preference of SS wafer over conventionally used silicon (Si) wafer is based on our previous study where use of SS wafer as a current collector enhanced the reversible capacity of thin carbon films to almost double as compared to the thin films prepared on Si wafer. Asfabricated 3-D carbon electrodes were then investigated for their electrochemical performance. At 0.1 Crate , Li-ion reversible capacity was found to be nearly 600 mAh/g after 165 continuous charge/discharge cycles. Nearly 100% coulombic efficiency and excellent cyclic stability confirms the potential use of such 3-D micro-patterned carbon electrodes for next generation Li-ion batteries.

Considering the complex hierarchical structure of bone, biomimicking the micro and nano level features should be an integral part of scaffold fabrication for successful bone regeneration. We aim to biomimic the microstructure and nanostructure of bone and study the effect of physical cues on cell alignment, proliferation, and differentiation. To achieve this, we have divided the scaffolds into groups: electrospun SU-8 nanofibers, electrospun SU-8 nanofibers with UV treatment, and micropatterned (20 μm sized ridges and grooves) SU-8 nanofibers by photolithography with UV treatment. Two types of culture conditions were applied: with and without osteoinduction medium. In vitro cell proliferation assays, protein estimation, alkaline phosphatase osteodifferentiation assay, live dead assay, and cell alignment studies were performed on these micropatterned nanofiber domains. Our findings show that patterned surface induced an early osteodifferentiation of mesenchymal stem cells even in absence of osteoinduction medium. An interesting similarity with the helicoidal plywood model of the bone was observed. The cells showed layering and rotation along the patterns with time. This resembles the in vivo anisotropic multilamellar bone tissue architecture thus, closely mimicking the subcellular features of bone. This might serve as a smart biomaterial surface for mesenchymal stem cell differentiation in therapeutics where the addition of external chemical factors is a challenge.

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An epoxy-based negative photoresist (SU-8) was spin-coated on stainless steel (SS) wafers followed by two-step pyrolysis in inert atmosphere to yield dense carbon films to be used as anodes for lithium (Li) ion batteries. The selection of SS wafer substrates was in accordance with commercial Li ion battery architecture. Cyclic voltammograms confirm the passive layer formation by electrolyte decomposition in the initial cycle. Galvanostatic charge/discharge experiments in the range 0.01-3 V performed at a C-rate=0.1 C confirms the reversible intercalation of Li ions and shows higher gravimetric reversible capacity for these photoresist-derived carbon films on SS wafer substrates than graphite (400 mAh/g vs. 372 mAh/g for graphite). This high reversible capacity may be attributed to high disorder in photoresist derived-carbon as characterized by X-ray diffraction and Raman spectroscopy.