P. Gopinath

Evaluation of surface properties of low density polyethylene (LDPE) films tailored by atmospheric pressure non-thermal plasma (APNTP) assisted co-polymerization and immobilization of chitosan for improvement of antifouling properties

This work describes the development of antifouling functional coatings on the surface of low density polyethylene (LDPE) films by means of atmospheric pressure non-thermal plasma (APNTP) assisted copolymerization using a mixture of acrylic acid and poly (ethylene glycol). The aim of the study was to investigate the antifouling properties of the plasma copolymerized LDPE films and the same was carried out as a function of deposition time with fixed applied potential of 14 kV. In a second stage, the plasma copolymerized LDPE films were functionalized with chitosan (CHT) to further enhance its antifouling properties. The surface hydrophilicity, structural, topographical and chemistry of the plasma copolymerized LDPE films were examined by contact angle (CA), X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Coating stability was also studied in detail over a storage time of 15 days by storing in water and air. The antifouling properties of the plasma copolymerized LDPE films were examined via protein adsorption and platelet adhesion studies. CA study showed significant changes in surface wettability after the coating process. XPS and FTIR analysis proved the presence of a dense multifunctional coating and an efficient immobilization of CHT. Substantial amendments in surface topography were observed, positively enhancing the overall surface hydrophilicity. Finally, in-vitro analysis showed excellent antifouling behavior of the surface modified LDPE films.

Applications of Nanofibers in Tissue Engineering

Abstract Tissue engineering is a multidisciplinary field that provides substitute methods for repairing damaged tissues by implanting natural, synthetic, and semisynthetic implants, which mimic fully functional tissues and organs. Today, remunerating nonfunctional tissue into functional forms is the biggest challenges in the field of tissue engineering. Academics, scientists, and tissue engineers from various fields have accepted these challenges and fabricated the artificial extracellular matrix known as a scaffold using biomaterials. These scaffolds mimic a native extracellular matrix, which contains proteins such as laminin and fibronectin, at nanoscale providing specific binding sites for the adhesion of cells on the scaffolds and regulating important cell behaviors, such as cell growth, shape, migration, and differentiation. Currently, there are three important methods available for fabricating nanofibrous scaffolds, phase separation, electrospinning, and self-assembly. Among these methods, electrospinning is the most widely used technique for tissue engineering applications. The synthesis of nanofibrous scaffolds by the electrospinning process can be achieved using a variety of natural and synthetic biomaterials. The development of 3D biodegradable scaffolds provides excellent support for cell adhesion, proliferation, and differentiation. Therefore, electrospun scaffolds are used for such distinct tissue engineering as epidermal, vascular, neural, musculoskeletal (including bone, cartilage, ligament, and skeletal muscle), and corneal applications. This chapter discusses the extensive applications of electrospun nanofibers in tissue engineering.

Nanomaterial Toxicity: A Challenge to End Users

Abstract Nanotechnology is broadly regarded as one of the most significant sources of new technology over recent decades, exhibiting enormous potential to benefit various areas of research and emerging as a new plateau of possibility with impacts on a broad range of industries and end-users. Today, it is one of the most promising tools in the fields of biomedicine, materials science, electronics, energy production, diagnostics, and therapeutics. Many studies have explored the effects of nanomaterials on human health and the environment. Nanomaterials, due to their small size, enter into the cells nucleus and blood-brain barrier easily and traverse the bodys organs via interactions with proteins and other biological components, evoking inflammatory and toxic immune responses. An hour is needed to understand and quantify how in vitro studies support human studies, because at nanoscale the properties and behavior of materials will be different from their bulk counterparts. There should be new FDA approved international guidelines to access toxicological data of nanomaterials in in vitro and in vivo models, and only then will it work out as the translational approach. In our review, we will try to educate the layman about the advantages and disadvantages of using nanomaterials and discuss the biophysiochemical behavior and properties of the nanomaterials present in the environment and currently employed in various biotechnological applications, as well as their method of toxicity evaluation.

6 – Surface analysis technique for assessing hemocompatibility of biomaterials

Abstract Integration of tissue is an important property when inducing transplant tolerance for a long-term allograft survival in the absence of continuous immunosuppressive treatment. For the successful implant, the hemocompatibility of the implantable biomaterials play an important role in order to induce long-term vitality of implants in the absence of immunosuppressive therapy to understand the interaction behavior of the different components of blood on the surface of the biomaterials. So, hemocompatibility is an essential property of biomaterials that can be measured by the interaction between the surface of the material and the various blood components, such as blood plasma proteins, erythrocytes, platelets, and leukocytes. The lack of hemocompatibility can lead to either rejection or the loss of function initially through the activation of the blood coagulation cascade followed by initiation of immune responses. Analysis of the biomaterial surface gives important information regarding its properties for manufacturing of biomedical devices like cardiovascular stents, bone joints, and other body implants. The characterization of the various modified surface of biomaterials provides information regarding its behavior in different applications like adhesion, corrosion, lubrication, welding, and biointeraction (like platelet, protein, and cell). The main focus of this chapter will be on analysis of surface properties for assessing interaction between blood and materials using various techniques. The role of modified surface of the biomaterials and its analysis helps to understand the properties of the biomaterials for development of novel biomedical devices and its in vitro and in vivo testing. There are various important techniques discussed in this chapter that are used for characterization of the biomaterial surface for assessing its interaction behavior with various blood components (platelets and blood proteins). These techniques include ellipsometry, TOF-SIMS, XPS, IR, SEM, AFM, and other important surface analysis techniques.

Polymer coatings for biocompatibility and reduced nonspecific adsorption

Abstract The pursuit of discovering a material with ideal surface properties and essential mechanical properties is a continued work in progress, particularly in the case of cardiovascular stent materials. The current generation of stent materials tends to trigger various adverse reactions such as inflammation, fibrosis, thrombosis, and infection. Most of these issues arise due to interface problems between the stent surface and its immediate environment. The main focus of most research groups therefore lies on modifying the surface of materials without altering the bulk properties. Most polymeric materials already possess the proper bulk properties, for instance, light weight-to-volume ratio, exceptional corrosion resistance, easy processing and molding, and excellent mechanical properties. Altering the surface properties of the already available polymers is therefore the most followed approach. Various surface modification methods have been studied extensively, resulting in enhancement of the hemocompatibility by decreasing either late-stage restenosis or acute thrombogenicity. This chapter focuses specifically on nonthermal plasma technology, as it is a well-established surface modification and has proved to be successful for various applications related to biomedical materials.