Browsing by Author "Sailaja, GS"

Now showing 1 - 5 of 5
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    Biomimetic approaches with smart interfaces for bone regeneration
    (JOURNAL OF BIOMEDICAL SCIENCE, 2016) Sailaja, GS; Ramesh, P; Vellappally, S; Anil, S; Varma, HK
    A 'smart tissue interface' is a host tissue-biomaterial interface capable of triggering favourable biochemical events inspired by stimuli responsive mechanisms. In other words, biomaterial surface is instrumental in dictating the interface functionality. This review aims to investigate the fundamental and favourable requirements of a 'smart tissue interface' that can positively influence the degree of healing and promote bone tissue regeneration. A biomaterial surface when interacts synergistically with the dynamic extracellular matrix, the healing process become accelerated through development of a smart interface. The interface functionality relies equally on bound functional groups and conjugated molecules belonging to the biomaterial and the biological milieu it interacts with. The essential conditions for such a special biomimetic environment are discussed. We highlight the impending prospects of smart interfaces and trying to relate the design approaches as well as critical factors that determine species-specific functionality with special reference to bone tissue regeneration.
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    Effect of Surface Functionalization on the Physicomechanical Properties of a Novel Biofunctional Copolymer
    (JOURNAL OF APPLIED POLYMER SCIENCE, 2011) Sailaja, GS; Ramesh, P; Varma, H
    The physicomechanical properties of functionally active poly(hydroxyethyl methacrylate-co-methyl methacrylate) [poly(HEMA-co-MMA)] are evaluated. It has been reported that the surface phosphorylated poly(HEMA-co-MMA) is capable of eliciting direct bone bonding when implanted in vivo. Hence, it is important to examine the physicomechanical property of the copolymer as a function of surface modification. The properties assessed are differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), equilibrium swelling, compressive strength, and dynamic mechanical analysis. According to the DSC data, the glass transition temperature, T-g of poly(HEMA-co-MMA) is not significantly altered by surface phosphorylation. The TGA results demonstrated that unmodified and surface phosphorylated copolymers have similar degradation profile. The differential thermal analysis further supports the data. The equilibrium swelling of functionalized poly(HEMA-co-MMA) in phosphate buffer saline ascertained that surface phosphorylation significantly increased the hydrophilicity of the copolymer. The study further illustrated that the percentage of equilibrium swelling appreciably increases with increase in HEMA content in the copolymer and reached a plateau after 100 h. Both compressive strength and compressive modulus of poly (HEMA-co-MMA) decreased due to surface phosphorylation while dynamic storage modulus value was not altered. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3509-3515, 2011
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    Hydroxyapatite filled chitosan-polyacrylic acid polyelectrolyte complexes
    (JOURNAL OF MATERIALS SCIENCE, 2003) Sailaja, GS; Velayudhan, S; Sunny, MC; Sreenivasan, K; Varma, HK; Ramesh, P
    Chitosan (CHI) has been complexed with polyacrylic acid (PAA) in the presence of hydroxyapatite (HAP) to prepare composites intended for bone substitute applications. Thermogravimetric analysis of the composite showed that the presence of HAP had little effect on the degradation profile of the polyelectrolyte complex (PEC), except for the onset of degradation. Optimum compressive strength was observed for 70-weight percentage HAP filled PEC. The morphological analysis revealed that the HAP particles were uniformly distributed in the PEC matrix. The results indicate that HAP filled PEC of CHI and PAA could be prepared following the proposed simple route. (C) 2003 Kluwer Academic Publishers.
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    In vitro mineralization and cell adhesion on surface modified poly (2-hydroxy ethyl methacrylate-co-methyl methacrylate)
    (BIOCERAMICS 18, PTS 1 AND 2, 2006) Sailaja, GS; Kumari, TV; Yokogawa, Y; Varma, HK
    Poly(2-hydroxyethyl methacrylate-co- methyl methacrylate) HM, was synthesized by free radical copolymerization, cross-linked with ethylene glycol dimethacrylate and phosphorylated. The phosphate coupling was ensured by ATR spectroscopy. The in vitro mineralization ability of the phosphorylated HM (designated as PHM) was investigated by studying the nucleation and growth of calcium phosphate on its surface by immersing in simulated body fluid (SBF) solution. The coating morphology was studied by SEM and the Ca/P ratio of the coating by EDX analysis. The cell adhesion behaviour of PHM was studied by seeding Human osteosarcoma (HOS) cells for one week followed by SEM analysis along with HM as control. It was observed that HOS cells exhibited biomineralization of calcium phosphate on the surface of HM as well as on PHM with a significantly higher amount on the surface of PHM as observed by von kossa staining method. The results show that PHM is capable of in vitro mineralization under simulated physiological condition, promotes cell adhesion by providing an excellent cell friendly surface and it exhibits biomineralization of calcium phosphate in presence of HOS cells.
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    Swelling behavior of hydroxyapatite-filled chitosan-poly (acrylic acid) polyelectrolyte complexes
    (JOURNAL OF APPLIED POLYMER SCIENCE, 2006) Sailaja, GS; Ramesh, P; Varma, HK
    A family of hydroxyapatite (HAP)-filled chitosan (CHI)-poly(acrylic acid) (PAA) polyelectrolyte complexes was prepared for the development of a degradable biocompatible organic matrix with nascent HAP that will degrade in vivo over a period of time. The effects of complexation on the degradation profile of the composites as well as the interaction between the CHI-PAA matrix and HAP in the composite system were evaluated by studying the swelling behavior of these composites in phosphate-buffered saline (PBS) by varying their CHI-PAA ratio and HAP content. All composite systems showed a general trend of three stages of swelling with the variation in the degree of equilibrium swelling. The percentage weight gain initially decreased in a linear way with increases in the HAP weight percentages, leading to a first equilibrium swelling, represented by the plateau; further increased to a greater extent; and finally stabilized. The CHI/PAA/HAP composites were stable in PBS up to a period of more than 45 days whereas the 50/50 CHI/PAA control sample showed a single equilibrium attained after a period of 288 h. Further exposure of the specimen to the medium led to its disintegration. It was also observed that, even though CHI and PAA were capable of binding HAP, because of the lack of efficient binding, the integrity of the CHI-HAP and PAA-HAP composites were lost within 48 h. The 50/50/80 CHI/PAA/HAP composition showed the minimum amount of swelling in the series. (c) 2006 Wiley Periodicals, Inc.