Multipurpose Polyurethane Antimicrobial Metal Composite Films via Wet Cast Technology

Rajkumar Nirmala,김학용,Duraisamy Kalpana,Rangaswamy Navamathavan,이양수 한국고분자학회 2013 Macromolecular Research Vol.21 No.8

We report on the preparation and characterization of polyurethane (PU) film containing metal particles and their antibacterial activity. The utilized PU films containing metal particles were prepared by a simple solvent evaporation method. The surface morphology, structure and optical properties of the resultant products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and UV-vis spectroscopy. The antibacterial activity was tested against four common food borne pathogenic bacteria, namely, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium,and Klebsiella pneumoniae by minimum inhibitory concentration (MIC) method. Our results demonstrated that no bactericidal activity was detected for the pristine PU film. Further on, antibacterial activity was observed to be more pronounced for the PU films containing metal particles which were attributed to the presence of metal in the PU thin films. Overall, this study demonstrates the fabrication of cheap, stable and effective material with excellent antimicrobial activity that can be utilized to inhibit the microbial growth associated with food stuff.

Antimicrobial activity of electrospun polyurethane nanofibers containing composite materials

Rajkumar Nirmala,Hak Yong Kim,박수진,Duraisamy Kalpana,Rangaswamy Navamathavan,박미라 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.5

We report on the preparation and characterization of electrospun polyurethane nanofibers containing silver,cactus, rosin and Scutellariae Radix. The utilized polyurethane nanofibers containing different composite materialswere prepared by a simple dip coating method. The morphology, structure and thermal characteristics of as-preparedcomposite nanofibers were studied by scanning electron microscopy, X-ray diffraction, Fourier transform infrared, Ramanspectroscopy and thermogravimetric analysis. The antimicrobial activity of the composite nanofibers was tested againsttwo common food borne pathogenic bacteria, Staphylococcus aureus and Escherichia coli, by the minimum inhibitoryconcentration method. Our results demonstrated that more pronounced antimicrobial activities were observed for thecomposite nanofibers. Overall, the fabrication of cheap, stable and effective material with excellent antimicrobial activitycan be utilized to inhibit the microbial growth associated with food stuff.

Bactericidal Efficacy of Electrospun Rosin/Poly(ε-caprolactone) Nanofibers

Rajkumar Nirmala,김학용,백우일,Rangaswamy Navamathavan,김태우,Duraisamy Kalpana,박미라,박수진 한국고분자학회 2014 Macromolecular Research Vol.22 No.2

Poly(ε-caprolactone) (PCL)-containing rosin nanofibers were prepared via electrospinning technique forbiomedical applications. To improve the biocompatibility properties, rosin was blended into PCL to prepare nanofibers. Nanofibers mats were prepared with different concentrations of rosin. The morphology, structure, and thermalproperties of the resultant PCL/rosin nanofibers were analyzed using scanning electron microscopy (SEM), X-raydiffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), andthermogravimetry (TGA) analysis. SEM images revealed that the nanofibers were well-oriented and had good incorporationof rosin. FTIR results indicated the various bonding groups of PCL/rosin nanofibers with stable structure. TGA analysis revealed that the onset degradation temperature was decreased with increasing rosin content in thenanofibers. The bactericidal activity of PCL/rosin nanofibers was also investigated. These results indicate that thePCL blended with rosin nanofibers can be utilized as a promising candidate material for many biomedical applications.

Association of Serum and Salivary Tumor Necrosis Factor-α with Histological Grading in Oral Cancer and its Role in Differentiating Premalignant and Malignant Oral Disease

Krishnan, Rajkumar,Thayalan, Dinesh Kumar,Padmanaban, Rajashree,Ramadas, Ramya,Annasamy, Ramesh Kumar,Anandan, Nirmala Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17

Background: Oral squamous cell carcinoma (OSCC) is an important malignancy throughout the world; early detection is an important criterion for achieving high cure rate. Out of the many reported markers for OSCC, this study validated the efficacy of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in differentially diagnosing premalignant oral lesions and OSCC. Also, the study aimed to correlate the levels of salivary and serum TNF-${\alpha}$ with clinicopathologic factors. Materials and Methods: A prospective experimental laboratory study was designed. Serum and salivary samples from 100 subjects in each group of healthy control, premalignant disease (PMD) and OSCC were collected for the study following appropriate exclusion and inclusion criteria. Serum and salivary level of TNF-${\alpha}$ was analysed by enzyme linked immunosorbent assay. The data obtained were subjected to appropriate statistical analysis. Results: Increased level of both serum and salivary TNF-${\alpha}$ was observed in OSCC subjects compared to healthy control and PMD group. Receiver operator characteristic curve analysis and area under curve values showed high specificity and sensitivity for salivary TNF-${\alpha}$ in differentiating OSCC from PMD and healthy controls. There was significant increase in TNF-${\alpha}$ level in moderately and poorly differentiated lesion compared to well differentiated lesion and in stage IV of clinical stage. A positive correlation was observed only with histological grading of OSCC and TNF-${\alpha}$. Conclusions: Salivary TNF-${\alpha}$ is proved to be superior for detecting OSCC. Increase in TNF-${\alpha}$ with histological grading and clinical staging suggests a role in prognosis.

Characterization of clonal immunoglobulin heavy (IGH) V-D-J gene rearrangements and the complementarity-determining region in South Indian patients with precursor B-cell acute lymphoblastic leukemia

Natarajan Sudhakar,Thangarajan Rajkumar,Kamalalayam Raghavan Rajalekshmy,Nirmala Karunakaran Nancy 대한혈액학회 2017 Blood Research Vol.52 No.1

Background: This study characterized clonal IG heavy V-D-J (IGH) gene rearrangements in South Indian patients with precursor B-cell acute lymphoblastic leukemia (precursor B-ALL) and identi-fied age-related predominance in VDJ rearrangements. Methods: IGH rearrangements were studied in 50 precursor B-ALL cases (common ALL=37, pre-B ALL=10, pro-B ALL=3) by polymerase chain reaction (PCR) heteroduplex analysis. Twenty randomly selected clonal IGH rearrangement sequences were analyzed using the IMGT/V-QUEST tool. Results: Clonal IGH rearrangements were detected in 41 (82%) precursor B-ALL cases. Among the IGHV1-IGHV7 subgroups, IGHV3 was used in 25 (50%) cases. Among the IGHD1-IGHD7 genes, IGHD2 and IGHD3 were used in 8 (40%) and 5 (25%) clones, respectively. Among the IGHJ1-IGHJ6 genes, IGHJ6 and IGHJ4 were used in 9 (45%) and 6 (30%) clones, respectively. In 6 out of 20 (30%) IGH rearranged sequences, CDR3 was in frame whereas 14 (70%) had rearranged sequences and CDR3 was out of frame. A so-matic mutation in Vmut/Dmut/Jmut was detected in 14 of 20 IGH sequences. On average, Vmut/Dmut/Jmut were detected in 0.1 nt, 1.1 nt, and 0.2 nt, respectively. Conclusion: The IGHV3 gene was frequently used whereas lower frequencies of IGHV5 and IGHV6 and a higher frequency of IGHV4 were detected in children compared with young adults. The IGHD2 and IGHD3 genes were over-represented, and the IGHJ6 gene was predom-inantly used in precursor-B-ALL. However, the IGH gene rearrangements in pre-cursor-B-ALL did not show any significant age-associated genotype pattern attributed to our population.

Characterization of clonal immunoglobulin heavy (IGH) V-D-J gene rearrangements and the complementarity-determining region in South Indian patients with precursor B-cell acute lymphoblastic leukemia

Natarajan Sudhakar,Thangarajan Rajkumar,Kamalalayam Raghavan Rajalekshmy,Nirmala Karunakaran Nancy 대한혈액학회 2017 Blood Research Vol.52 No.1

Background: This study characterized clonal IG heavy V-D-J (IGH) gene rearrangements in South Indian patients with precursor B-cell acute lymphoblastic leukemia (precursor B-ALL) and identi-fied age-related predominance in VDJ rearrangements. Methods: IGH rearrangements were studied in 50 precursor B-ALL cases (common ALL=37, pre-B ALL=10, pro-B ALL=3) by polymerase chain reaction (PCR) heteroduplex analysis. Twenty randomly selected clonal IGH rearrangement sequences were analyzed using the IMGT/V-QUEST tool. Results: Clonal IGH rearrangements were detected in 41 (82%) precursor B-ALL cases. Among the IGHV1-IGHV7 subgroups, IGHV3 was used in 25 (50%) cases. Among the IGHD1-IGHD7 genes, IGHD2 and IGHD3 were used in 8 (40%) and 5 (25%) clones, respectively. Among the IGHJ1-IGHJ6 genes, IGHJ6 and IGHJ4 were used in 9 (45%) and 6 (30%) clones, respectively. In 6 out of 20 (30%) IGH rearranged sequences, CDR3 was in frame whereas 14 (70%) had rearranged sequences and CDR3 was out of frame. A so-matic mutation in Vmut/Dmut/Jmut was detected in 14 of 20 IGH sequences. On average, Vmut/Dmut/Jmut were detected in 0.1 nt, 1.1 nt, and 0.2 nt, respectively. Conclusion: The IGHV3 gene was frequently used whereas lower frequencies of IGHV5 and IGHV6 and a higher frequency of IGHV4 were detected in children compared with young adults. The IGHD2 and IGHD3 genes were over-represented, and the IGHJ6 gene was predom-inantly used in precursor-B-ALL. However, the IGH gene rearrangements in pre-cursor-B-ALL did not show any significant age-associated genotype pattern attributed to our population.

Autoclave Mediated Synthesis of Silver Nanoparticles Using Aqueous Extract of Canna indica L. Rhizome and Evaluation of Its Antimicrobial Activity

Narayanasamy Tamil Selvi,Rangaswamy Navamathavan,김학용,Rajkumar Nirmala 한국고분자학회 2019 Macromolecular Research Vol.27 No.11

Current trends will affirm that the use of nanotechnology principles has become an important area of research today, due to the wide range of applications of these technologies in various fields and industries. By the same token, silver nanoparticles have been gaining more importance due to their optical, electrical, thermal and biological properties, when comparing these qualities to other metal nanoparticles. The use of plants for silver nanoparticle synthesis has also drawn attention from the scientific research community, because of its rapid, eco-friendly, non-pathogenic and economical protocols. Thus, in the present study, we report on the synthesis process of silver nanoparticles, by using aqueous rhizome extract of Canna indica Linn. In this case, the silver nanoparticle synthesis was performed by using a simple autoclave method. The utilization of a fixed ratio of plant extract to metal salt was prepared, and the mixture was allowed to autoclave for 15 minutes. The colour change was observed as resembling the hue of red wine, which was evidenced in the noted formation of silver nanoparticles. The synthesized silver nanoparticles were characterized by using UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and high resolution transmission electron microscopy (HR-TEM) analyses. The silver nanoparticles were witnessed for any noted antimicrobial activity against the identified and selected bacterial strains.

Preparation of nylon-6/chitosan composites by nanospider technology and their use as candidate for antibacterial agents

Mohamed Hassan El-Newehy,Salem Slayyem Al-Deyab,Rajkumar Nirmala,Ahmed Abdel-Megeed,Hak Yong Kim 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2

Electrospun nylon-6/chitosan (nylon-6/Ch) nanofibers were prepared by nanospider technology. Quaternary ammonium salts as antibacterial agent were immobilized onto electrospun nylon-6/Ch nanofibers via surface modification by soaking the mat in aqueous solution of glycidyltrimethylammonium chloride (GTMAC) at room temperature overnight to give nylon-6/N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride (nylon-6/HTCC). The morphological,structural and thermal properties of the nylon-6/ch nanofibers were studied by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). Biological screening has demonstrated the antibacterial activity of the electrospun nanofibers against Gram negative bacteria, Escherichia coli 35218, and Pseudomonas aeruginosa and Gram positive bacteria,Staphylococcus aureus 24213 among the tested microbes. Thus, the study ascertains the value of the use of electrospun nanofibers, which could be of considerable interest to the development of new antibacterial materials for biomedical applications.

Facile stabilization process of polyacrylonitrile-based electrospun nanofibers by spraying 1% hydrogen peroxide and electron beam irradiation

Choi, Yuri,Park, Mira,Kyoung Shin, Hye,Liu, Yanan,Choi, Ja-Wun,Nirmala, Rajkumar,Park, Soo-Jin,Kim, Hak-Yong Elsevier 2014 Materials letters Vol.123 No.-

Polyacrylonitrile (PAN)-based electrospun nanofibers (NFs) were irradiated using an electron beam. 1% hydrogen peroxide (H2O2) solution was sprayed during Electron Beam Irradiation (EBI) as a further oxidative stabilization process. Fourier transform infrared spectroscopy (FT-IR) and X-ray Diffraction (XRD) of electrospun PAN NFs indicated that the transformation of C=N to C=N groups was accelerated by spraying 1% H2O2 solution. EBI-H2O2 stabilized PAN NFs reduce the onset temperature, extends the exothermic reaction, and improves the stabilization at a significantly lower dose of irradiation (50 kGy) as a result of cyclization and oxidation of PAN molecules caused by 1% H2O2 solution. (c) 2014 Elsevier B.V. All rights reserved.