S.V. Nair

Curcumin-loaded biocompatible thermoresponsive polymeric nanoparticles for cancer drug delivery

This study aims at the formulation of curcumin with biodegradable thermoresponsive chitosan-g-poly (N-vinylcaprolactam) nanoparticles (TRC-NPs) for cancer drug delivery. The spherical curcumin-loaded nanoparticles of size 220 nm were characterized, and the biological properties were studied using flow cytometry and cytotoxicity by MTT assay. The in vitro drug release was higher at above LCST compared to that at below LCST. TRC-NPs in the concentration range of 100-1000 μg/mL were non-toxic to an array of cell lines. The cellular localization of the curcumin-loaded TRC-NPs was confirmed from green fluorescence inside the cells. The time-dependent curcumin uptake by the cells was quantified by UV spectrophotometer. Curcumin-loaded TRC-NPs showed specific toxicity to cancer cells at above their LCST. Flow cytometric analysis showed increased apoptosis on PC3 compared to L929 by curcumin-loaded TRC-NPs. These results indicate that novel curcumin-loaded TRC-NPs could be a promising candidate for cancer drug delivery.

Preparation, characterization, bioactive and metal uptake studies of alginate/phosphorylated chitin blend films

Alginate/phosphorylated chitin (P-chitin) blend films were prepared by mixing of 2% of alginate and P-chitin in water and then cross-linked with 4% CaCl2 solution. The blended films were characterized by FT-IR. Then, the bioactivity of blend films was studied by biomimetic method in simulated body fluid solution (SBF) for 7, 14 and 21 days. After 7, 14 and 21 days and films were characterized by FT-IR and SEM studies. The SEM and FT-IR studies showed that the hydroxyapatite was formed on the surface of the blend films after 7, 14 and 21 days in the SBF solution. These studies confirmed that the alginate/P-chitin blend films are bioactive. Furthermore, the adsorption of Ni2+, Zn2+ and Cu2+ onto alginate/P-chitin blend films has been investigated. The parameters studied include the pH, contact time, and initial metal ion concentrations. The maximum adsorption capacity of alginate/P-chitin blend films for Ni2+, Zn2+ and Cu2+ at pH 5.0 was found to be 5.67, 2.85 and 11.7 mg/g, respectively. These results suggest that alginate/P-chitin blend films-based technologies may be developed for water purification and metal ions separation and enrichment.

Electrospun Nanofibrous Scaffolds-Current Status and Prospects in Drug Delivery

Controlled delivery systems are used to improve therapeutic efficacy and safety of drugs by delivering them over a period of treatment to the site of action at a rate dictated by the need of the physiological environment. A wide variety of polymeric materials, either biodegradable or non-biodegradable but biocompatible, can be used as delivery matrices. Recently, nanofibrous scaffolds, such as the systems fabricated by electrospinning or electrospraying, have been used in the field of biomedical engineering as wound dressings, scaffolds for tissue engineering, and drug delivery systems. The electrospun nanofibrous scaffolds can be used as carriers for various types of drugs, genes, and growth factors, whereby the release profile can be finely controlled by modulation of the scaffold’s morphology, porosity, and composition. The main advantage of this system is that it offers site-specific delivery of any number of therapeutics from the scaffold into the body. The aim of this chapter is to review the recent advances on electrospun nanofibrous scaffolds based on biodegradable and biocompatible polymers for controlled drug and biomolecule delivery applications. The use of electrospun scaffolds as drug carriers is promising for future biomedical applications, particularly in the prevention of post-surgical adhesions and infections, for postoperative local chemotherapy, and for bone and skin tissue engineering.

5-Fluorouracil loaded fibrinogen nanoparticles for cancer drug delivery applications

In this study, 5-flurouracil loaded fibrinogen nanoparticles (5-FU-FNPs) were prepared by two step coacervation method using calcium chloride as cross-linker. The prepared nanoparticles were characterized using DLS, SEM, AFM, FT-IR, TG/DTA and XRD studies. Particle size of 5-FU-FNPs was found to be 150-200 nm. The loading efficiency (LE) and in vitro drug release was studied using UV spectrophotometer. The LE of FNPs was found to be ∼90%. The cytotoxicity studies showed 5-FU-FNPs were toxic to MCF7, PC3 and KB cells while they are comparatively non toxic to L929 cells. Cellular uptake of Rhodamine 123 conjugated 5-FU-FNPs was also studied. Cell uptake studies demonstrated that the nanoparticles are inside the cells. These results indicated that FNPs could be useful for cancer drug delivery.

Preparation, Characterization and Cell Attachment Studies of Electrospun Multi-scale Poly(caprolactone) Fibrous Scaffolds for Tissue Engineering

Electrospun nano, micro and micro/nano (multiscale) poly(caprolactone) (PCL) fibrous scaffolds with and without nano hydroxyapatite (nHAp) was prepared. All the scaffolds were evaluated for its spectroscopic, morphological, mechanical, thermal, cell attachment and protein adsorption properties. The cell attachment studies showed that cell activity on the nano-fibrous, as well as multi-scale scaffolds with and without nHAp was higher compared to micro-fibrous scaffolds. A time dependent cell attachment study on aligned micro-fibers was carried out to elucidate the difference in cell interaction on micro-fibers. The cell activity, proliferation and total protein adsorption on the nano-fibers/nano-fibers with nHAp was significantly higher than on the micro-fibers, although the adsorption per unit area was less on the nano-fibers due to the much higher surface area of nano-fibers. These results suggest that a combination of a micro- and nano-fiber hierarchical scaffold could be more beneficial for tissue engineering applications than the individual scaffolds provided the amount of nano- fibers could be suitably optimized.

Preparation of Budesonide-Loaded Polycaprolactone Nanobeads by Electrospraying for Controlled Drug Release

Corticosteroids such as budesonide are the drugs of choice for the treatment of inflammatory disorders with an inherent limitation, viz., rapid elimination. To overcome this constraint and attain sustained release, budesonide was encapsulated in a biodegradable polymer, polycaprolactone (PCL), by DC electrospraying. By varying the experimental parameters involved in electrospraying such as applied voltage, flow rate, viscosity as well as conductivity of the polymer solution, the dimensionality of nanostructures was tuned from 1-D nanofibers to spherical nanoparticles. By adopting this rapid and viable method of DC electrospraying, we successfully prepared aqueous suspensions of nearly monodispersed, nano-sized drug encapsulated PCL. Drug encapsulation efficiency, in vitro drug release as well as biocompatibility studies of budesonide-loaded PCL nanobeads were carried out. The cytocompatible nanobeads prepared by electrospraying exhibited good encapsulation efficiency (approx. 75%), with controlled drug release enabled by the dissolution of the polymer. Our results demonstrate the potential of this novel technique of electrospraying in developing efficient drug encapsulated polymeric nanocarriers possessing sustained drug release profile.

Preparation, characterization, bioactive and cell attachment studies of α-chitin/gelatin composite membranes

The chitin/gelatin composite membranes were prepared by mixing of chitin hydrogel with gelatin. The prepared composite membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical, swelling, enzymatic degradation and thermal studies. The XRD pattern of the chitin/gelatin composite membranes showed almost the same pattern as alpha-chitin. The bioactivity studies of these chitin/gelatin membranes were carried out with the simulated body fluid solution (SBF) for 7, 14 and 21 days followed by the characterization with the scanning electron microscopy (SEM) and Energy Dispersive Spectrum (EDS) studies. The SEM and EDS studies confirmed the formation of calcium phosphate layer on the surface of chitin/gelatin membranes. Biocompatibility of the chitin/gelatin membrane was assessed using human MG-63 osteoblast-like cells. After 48 h of incubation, it was found that the cells had attached and completely covered the membrane surface. Thus, the prepared chitin/gelatin membranes are bioactive and are suitable for cell adhesion suggesting that these membranes can be used for tissue-engineering applications.

Fabrication of three-dimensional nano, micro and micro/nano scaffolds of porous poly(lactic acid) by electrospinning and comparison of cell infiltration by Z-stacking/three-dimensional projection technique

The use of electrospun extracellular matrix (ECM)-mimicking nanofibrous scaffolds for tissue engineering is limited by poor cellular infiltration. The authors hypothesised that cell penetration could be enhanced in scaffolds by using a hierarchical structure where nano fibres are combined with micron-scale fibres while preserving the overall scaffold architecture. To assess this, we fabricated electrospun porous poly(lactic acid) (PLA) scaffolds having nanoscale, microscale and combined micro/nano architecture and evaluated the structural characteristics and biological response in detail. Although the bioactivity was intermediate to that for nanofibre and microfibre scaffold, a unique result of this study was that the micro/nano combined fibrous scaffold showed improved cell infiltration and distribution than the nanofibrous scaffold. Although the cells were found to be lining the scaffold periphery in the case of nanofibrous scaffold, micro/nano scaffolds had cells dispersed throughout the scaffold. Further, as expected, the addition of nanoparticles of hydroxyapatite (nHAp) improved the bioactivity, although it did not play a significant role in cell penetration. Thus, this strategy of creating a three-dimensional (3D) micro/nano architecture that would increase the porosity of the fibrous scaffold and thereby improving the cell penetration, can be utilised for the generation of functional tissue engineered constructs in vitro.

MnO2 nano/micro hybrids for supercapacitors: “Nano's Envy, Micro's pride”

The present study provides the first reports on a low temperature molten salt route which can generate unique architecture of MnO2 nanospikes arrayed in a peculiar fashion to form micron sized ball morphology. This morphology when employed as supercapacitor electrodes gives an advantage of surface relaxation during the charge–discharge process making it super stable. The study highlights the advantages of nanostructuring of microparticles which can answer the toxicity issues and their potential as a commercial product. This claim in the present study has been validated by cell toxicity study on human dermal fibroblasts, which established that a nano/micro hybrid structure can be relatively less toxic. Cytoskeleton rearrangements were also observed as the size of MnO2 was reduced from micron to nanoscale. A mechanism of the structure formation and the influence of the salt in controlling the process parameters as well as the morphology are also proposed. These electrodes in coin cells exhibited specific mass capacitance value as high as 1100 F g−1 with a power density and energy density of 4.5 W h kg−1 and 14 kW kg−1, respectively.

Exploitation of Detergent Thermodynamics in the Direct Solubilization of Myelin Membrane Proteins for Two-dimensional Gel Electrophoresis for Proteomic Analysis

Performing 2‐DE of lipid‐rich multilamellar membranes like myelin is a cumbersome task. However, for understanding its molecular organization and changes during diseases, identification of proteins of myelin is essential. Although the 2‐D‐proteomic approach of myelin has been employed to understand the myelin proteome, representation of myelin proteins in its entirety is still a challenge. 2‐DE profiling of myelin proteins is very important for the detection of immuno‐reactivity to myelin proteins from various biological fluids following Western blotting in diseases like multiple sclerosis. Here we developed a novel approach by exploiting the thermodynamic principles behind detergent‐mediated solubilization of myelin membranes without any conventional processing of myelin involving precipitation of myelin proteins. We show that the addition of myelin to ASB‐14‐4 resulted in significant increase in protein representation of myelin in 2‐DE compared with the addition of ASB‐14‐4 to myelin. Moreover, the number and resolution of spots are significantly higher in myelin to ASB‐14‐4 strategy than other strategies of myelin sample processing such as ASB‐14‐4 to myelin or ethanol or acetone or methanol–ammonium acetate precipitation of myelin proteins. In addition, the step involves no precipitation that selective removal of any proteins as a result of precipitation is nil and a qualitative representation of myelin proteins in a 2‐D gel is achieved.