Tippabattini Jayaramudu

Nano zinc oxide-sodium alginate antibacterial cellulose fibres

Abstract In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the ‘rod-like’ shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM–EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress–strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide–sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications.

A mini review on hydrogels classification and recent developments in miscellaneous applications

Hydrogels are composed of three-dimensional smart and/or hungry networks, which do not dissolve in water but swell considerably in an aqueous medium, demonstrating an extraordinary ability to absorb water into the reticulated structure. Such inherent feature is a subject of considerable scientific research interest which leads to a dominating path in extending their potential in hi-tech applications. Over the past decades, significant progress has been made in the field of hydrogels. Further, explorations are continuously being made in all directions at an accelerated pace for their extensive usage. In view of this, the present review discusses the subject on the miscellaneous hydrogels with regard to their raw materials, methods of fabrication and applications. In addition, this article summarizes the classification of hydrogels, based on their cross-linking and physical states. Lately, a brief outlook on the future prospects of hydrogels is also presented.

Antibacterial nanocomposite hydrogels for superior biomedical applications: a Facile eco-friendly approach

In this scientific paper, we report a facile and eco-friendly fabrication of antibacterial nanocomposite hydrogels of Au-core Ag-shell nanoparticles, embedded within Carbopol® 980 NF/Noveon® AA-1 polycarbophil acrylic acid polymeric matrix. The aim of the study was to investigate whether these nanocomposite hydrogels have the potential to be used for bacterial inactivation applications. The key feature was that, unlike the use of chemical reductants, auxiliary stabilizers and specialized expensive equipment, the Au-core Ag-shell nanoparticles (∼15 ± 3 nm) were synthesized utilizing aqueous mint leaf extracts. The developed hydrogels were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy/energy-dispersive spectroscopy and thermogravimetric analysis. Swelling studies were performed in phosphate buffered saline (pH 7.4) solution. A sustained antibacterial study against E. coli (G−) and B. subtilis (G+) showed their excellent antibacterial efficiency, which suggested that the developed hydrogels are potential candidates for a wide range of biomedical applications.

Removal of dye by carboxymethyl cellulose, acrylamide and graphene oxide via a free radical polymerization process

Carboxymethyl cellulose has been used for the design of novel engineered hydrogels in order to obtain effective three-dimensional structures for industrial applications. In this work, dye removal carboxymethyl cellulose-acrylamide-graphene oxide (CMC-AM-GO) hydrogels were prepared by a free-radical polymerization method. The GO was developed by the modified Hummers method. The CMC-AM-GO and GO were characterized by FTIR, XRD and SEM. The swelling and swelling kinetics were calculated using gravimetric process. The kinetic parameter, swelling exponent values [n=0.59-0.7507] explained the fact that the CMC-AM-GO hydrogles have super Case II diffusion transport mechanism. CMCx-AM-GO (x=1-4) and CMC-AM hydrogels were used for removal of Acid Blue-133. The result explains that composite hydrogels significantly removed the acid blue when compared to the neat hydrogel. The maximum AB absorption (185.45mg/g) capacity was found in the case of CMC2-AM-GO hydrogel. Therefore, cellulose-based GO hydrogels can be termed as smart systems for the abstraction of dye in water purification applications.

5-Fluorouracil Loaded Chitosan–PVA/Na+MMT Nanocomposite Films for Drug Release and Antimicrobial Activity

In the present study, chitosan and polyvinyl alcohol (PVA) were blended with different concentrations of sodium montmorillonite (Na+MMT) clay solution by a solvent casting method. X-ray diffraction and transition electron microscope results show that the film properties are related to the co-existence of Na+MMT intercalation/exfoliation in the blend and the interaction between chitosan–PVA and Na+MMT. 5-Fluorouracil (5-FU) was loaded with chitosan–PVA/Na+MMT nanocomposite films for in vitro drug delivery study. The antimicrobial activity of the chitosan–PVA/Na+MMT films showed significant effect against Salmonella (Gram-negative) and Staphylococcus aureus (Gram-positive), whereas 5-FU encapsulated chitosan–PVA/Na+MMT bio-nanocomposite films did not show any inhibition against bacteria. Our results indicate that combination of a flexible and soft polymeric material with high drug loading ability of a hard inorganic porous material can produce improved control over degradation and drug release. It will be an economically viable method for preparation of advanced drug delivery vehicles and biodegradable implants or scaffolds.

Preparation and characterization of hydrogels from polyvinyl alcohol and cellulose and their electroactive behavior

ABSTRACT This paper reports polyvinyl alcohol/cellulose-based electroactive hydrogels for actuator applications. The polyvinyl alcohol/cellulose electroactive hydrogels were obtained by physical crosslinking of polyvinyl alcohol and cellulose. The formation of the polyvinyl alcohol/cellulose hydrogel structure, its thermal stability, crystallinity, and mechanical properties were studied by using the Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and mechanical test. The studies reveal that the cellulose is uniformly reacted with hydroxyl groups of polyvinyl alcohol by intermolecular bond formation. The cellulose content along with actuation voltage and frequency of electroactive hydrogels influence their displacement behavior.

Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid

The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications.

Calcinated tea and cellulose composite films and its dielectric and lead adsorption properties.

In this paper, calcinated tea and cellulose composite (CTCC) films were fabricated via solution casting method. Chemical structure, morphology, crystallinity and thermal stability of the fabricated films were characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The effect of calcinated tea loading on the properties of the prepared CTCC films was studied. The results suggest that the prepared CTCC films show higher mechanical properties, thermal stability and dielectric constant than the neat cellulose film. In addition, the CTCC films adsorb Pb2+ ions and its adsorption performance depends on the calcinated tea content and pH level. The CTCC films are useful for sensors, flexible capacitor as well as lead adsorption applications.

Transparent and semi-interpenetrating network P(vinyl alcohol)- P(Acrylic acid) hydrogels: pH responsive and electroactive application

ABSTRACT In this paper, poly(vinyl alcohol)-poly(acrylic acid) based transparent semi-interpenetrating network (semi-IPN) hydrogels were synthesized by using a solvent mixture of dimethyl sulfoxide and deionized water via free radical polymerization and subsequent freeze-thaw technique. The formation of the semi-IPN hydrogels was conformed from FT-IR spectra. The acrylic acid concentration effect on the hydrogels was investigated in terms of transparency, crystalline structure and thermal stability by using UV-visible spectroscopy, X-ray diffraction and thermogravimetric analysis. Swelling behaviours of the semi-IPNPAP hydrogels were studied in deionized water and different pH solutions. The compression and electroactive behaviour was tested in fully hydrated stage by using compression test and by applying electrical voltage. The hydrogels showed displacements under the applying voltage and detailed experiment is illustrated.

Biomaterials: Design, Development and Biomedical Applications

The explorations in medical sciences have provided innumerable biomaterials that can perform, augment, or replace the natural function of a defective organ by interacting with the biological system. These materials represent a unique class of biomedical functional materials that potentially perform broad spectrum of biological activities in the absence of the original living tissue/organ, thereby replace the problems encountered with the defective tissue/organ and support smooth functioning of the organ and the living organism. The day-to-day increased demand in the medical field for the bioalternatives that could be able to perform the living activities of bodily organs has raised the interest of the researchers to design novel biomaterials. Hence, the study of biomaterials has become crucial for the material scientists and engineers to understand more about biomaterials. In that point of view, the present chapter focuses on the design, development, and biomedical applications of biomaterials.