scholarly journals Antibacterial Films Based on PVA and PVA–Chitosan Modified with Poly(Hexamethylene Guanidine)

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2093 ◽  
Author(s):  
Ewa Olewnik-Kruszkowska ◽  
Magdalena Gierszewska ◽  
Ewelina Jakubowska ◽  
Iwona Tarach ◽  
Vladimir Sedlarik ◽  
...  
Keyword(s):  
Polymeric Films ◽  
Attenuated Total Reflectance ◽  
Poly Vinyl Alcohol ◽  
Resonance Spectroscopy ◽  
Force Microscopy ◽  
Color Changes ◽  
Atomic Force ◽  
Escherichia Coli Bacteria ◽  
Thermal Stability Of ◽  
Biocidal Properties

In this study, thin, polymeric films consisting of poly(vinyl alcohol) (PVA) and chitosan (Ch) with the addition of poly(hexamethylene guanidine) (PHMG) were successfully prepared. The obtained materials were analyzed to determine their physicochemical and biocidal properties. In order to confirm the structure of PHMG, nuclear magnetic resonance spectroscopy (1H NMR) was applied, while in the case of the obtained films, attenuated total reflectance infrared spectroscopy with Fourier transform (FTIR-ATR) was used. The surface morphology of the polymer films was evaluated based on atomic force microscopy. Furthermore, the mechanical properties, color changes, and thermal stability of the obtained materials were determined. Microbiological tests were performed to evaluate the biocidal properties of the new materials with and without the addition of PHMG. These analyses confirmed the biocidal potential of films modified by PHMG and allowed for comparisons of their physicochemical properties with the properties of native films. In summary, films consisting of PVA and PHMG displayed higher antimicrobial potentials against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in comparison to PVA:Ch-based films with the addition of PHMG.

Novel Poly(vinyl alcohol)/Clay Nanocomposite Film Prepared by the Heterogeneous Saponification of Poly(vinyl acetate)/Clay Nanocomposite Film

2020 ◽  
Vol 12 (3) ◽  
pp. 319-325
Author(s):  
Seong Baek Yang ◽  
Sung Min Park ◽  
Dong Jun Kwon ◽  
Jae-Cheon Shin ◽  
Yeasmin Sabina ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nanocomposite Film ◽  
Poly Vinyl Alcohol ◽  
Thermal Gravimetric ◽  
Force Microscopy ◽  
Atomic Force ◽  
Entire Structure ◽  
Slow Progress ◽  
First Time ◽  
Thermal Stability Of

A novel PVA/clay (MMT) film is prepared for the first time based on the saponification of the PVAc/MMT film in the presence of heterogeneous conditions. With the help of optical microscopy, the characteristics and surface morphology of the saponified PVA/MMT film is confirmed. It is found to contain black MMT nanoparticles in PVAc films as the content of MMT increased. According to atomic force microscopy results, PVAc/MMT films shows unexpected surface roughness owing to the slow progress of the saponification reaction in the presence of MMT contents in the PVAc matrix. The thermal stability of the PVA/MMT film is measured using thermal gravimetric analyses. The results indicate that thermal stability increases significantly when the MMT concentration increases. The entire structure of the PVA/MMT nanocomposite has been elucidated using XRD. To prove the differences between the PVAc/MMT and the PVA/MMT films, XRD measurements and Fourier transform Infrared spectroscopy analyses are utilized.

Influence of trisilanol isooctyl POSS content on the structure, morphology and rheological properties of thermoplastic polyurethane (TPU)

2020 ◽  
Vol 40 (9) ◽  
pp. 727-735
Author(s):  
Rudinei Fiorio ◽  
Chaitanya Danda ◽  
João Maia
Keyword(s):  
Thermal Stability ◽  
Rheological Properties ◽  
Thermoplastic Polyurethane ◽  
Reactive Extrusion ◽  
Strain Rates ◽  
Force Microscopy ◽  
Atomic Force ◽  
Extensional Strain ◽  
Oligomeric Silsesquioxane ◽  
Thermal Stability Of

AbstractIn this study, thermoplastic polyurethanes (TPUs) containing trisilanol isooctyl polyhedral oligomeric silsesquioxane (POSS), a reactive nanofiller, were synthesized and characterized rheologically and morphologically, and the effects of POSS content on the melt thermal stability of the TPUs are investigated. Samples containing 0, 0.23, 0.57, 1.14, and 2.23% (w/w) POSS were synthesized by reactive extrusion and characterized by Fourier transform infrared spectroscopy (FTIR), oscillatory and extensional rheometry, atomic force microscopy (AFM), and small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). The rheological properties of molten TPU are time-dependent and the melt thermal stability of the TPU is maximal at 1.14% of POSS. The addition of 0.23 and 0.57% POSS promotes strain-hardening at low extensional strain rates (0.01 and 0.10 s−1), not affecting the extensional characteristics at higher strain rates. The addition of increasing amounts of POSS leads to the formation of POSS-rich clusters well dispersed in the TPU matrix. SAXS and WAXS results show that the POSS domains are amorphous and that POSS does not modify the crystalline structure of TPU. Therefore, this work indicates that synthesizing TPU in the presence of trisilanol isooctyl POSS can increase the melt thermal stability of the polymer, facilitating its processing.

Preparation and Characterization of Chitosan-Casein Phosphopeptides Biocomposite Coatings on the Medical Titanium Alloy

2011 ◽  
Vol 480-481 ◽  
pp. 1065-1069
Author(s):  
Bin Liu ◽  
Lin Wang ◽  
Yin Zhong Bu ◽  
Sheng Rong Yang ◽  
Jin Qing Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Attenuated Total Reflectance ◽  
Ti Alloy ◽  
Force Microscopy ◽  
Implant Materials ◽  
Atomic Force ◽  
Casein Phosphopeptides ◽  
Potential Applications ◽  
First Time

Titanium (Ti) and its alloys have been applied in orthopedics as one of the most popular biomedical metallic implant materials. In this work, to enhance the bioactivity, the surface of Ti alloy pre-modified by silane coupling agent and glutaraldehyde was covalently grafted with chitosan (CS) via biochemical multistep self-assembled method. Then, for the first time, the achieved surface was further immobilized with casein phosphopeptides (CPP), which are one group of bioactive peptides released from caseins in the digestive tract and can facilitate the calcium adsorption and usage, to form CS-CPP biocomposite coatings. The structure and composition of the fabricated coatings were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). As the experimental results indicated, multi-step assembly was successfully performed, and the CS and CPP were assembled onto the Ti alloy surface orderly. It is anticipated that the Ti alloys modified by CS-CPP biocomposite coatings will find potential applications as implant materials in biomedical fields.

scholarly journals Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2348 ◽  
Author(s):  
Katrin Niegelhell ◽  
Thomas Ganner ◽  
Harald Plank ◽  
Evelyn Jantscher-Krenn ◽  
Stefan Spirk
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Plasmon Resonance ◽  
Protein Adsorption ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Resonance Spectroscopy ◽  
Carbohydrate Binding ◽  
Force Microscopy ◽  
Atomic Force ◽  
Slow Kinetics

Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.

scholarly journals 3D Surface Profile and Color Stability of Tooth Colored Filling Materials after Bleaching

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Bryant Anthony Irawan ◽  
Stacey Natalie Irawan ◽  
Sam’an Malik Masudi ◽  
Ninin Sukminingrum ◽  
Mohammad Khursheed Alam
Keyword(s):  
Surface Profile ◽  
Color Stability ◽  
Tooth Bleaching ◽  
Force Microscopy ◽  
Color Changes ◽  
Filling Materials ◽  
Atomic Force ◽  
3D Surface ◽  
Restorative Materials ◽  
Dental Restorative

This study aims to evaluate the effects of vital tooth bleaching with carbamide peroxide home bleaching and in-office bleaching on the color stability and 3D surface profile of dental restorative filling materials. Thirty discs (n=30) measure 6 mm in diameter and 2 mm thick for each of three restorative materials. These are nanofilled composite Filtek Z350 XT, the submicron composite EsteliteΣQuick, and nanofilled glass ionomer Ketac N100 nanoionomer and were fabricated in shade A2. Each group was further divided into three subgroups (n=10): subgroup A (Opalescence PF), subgroup B (Opalescence Boost in-office bleaching), and subgroup C (distilled water) serving as control. Samples were bleached according to the manufacturer’s instructions for a period of two weeks. The Commission Internationale de L’Eclairage (CIEL*,a*,b*) system was chosen for image processing, while 3D surface profile was tested with atomic force microscopy (AFM). Statistical analyses were performed with the Mann-Whitney tests and Krusal-Wallis with aPvalue of ≤0.05. The three restorative materials showed significant color changes (ΔE);P≤0.05. In diminishing order, the mean color changes recorded were EsteliteΣ(3.82 ± 1.6) > Ketac Nano (2.97 ± 1.2) > Filtek Z350 XT (2.25 ± 1.0). However, none of the tested materials showed statistically significant changes in surface roughness;P>0.05.

scholarly journals Nanostructured Chitosan/Maghemite Composites Thin Film for Potential Optical Detection of Mercury Ion by Surface Plasmon Resonance Investigation

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1497
Author(s):  
Nurul Illya Muhamad Fauzi ◽  
Yap Wing Fen ◽  
Nur Alia Sheh Omar ◽  
Silvan Saleviter ◽  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
...  
Keyword(s):  
Thin Film ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Mercury Ion ◽  
Resonance Spectroscopy ◽  
Force Microscopy ◽  
Sensing Applications ◽  
Atomic Force ◽  
Fe2o3 Thin Film

In this study, synthesis and characterization of chitosan/maghemite (Cs/Fe2O3) composites thin film has been described. Its properties were characterized using Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and ultraviolet-visible spectroscopy (UV-Vis). FTIR confirmed the existence of Fe–O bond, C–N bond, C–C bond, C–O bond, O=C=O bond and O–H bond in Cs/Fe2O3 thin film. The surface morphology of the thin film indicated the relatively smooth and homogenous thin film, and also confirmed the interaction of Fe2O3 with the chitosan. Next, the UV-Vis result showed high absorbance value with an optical band gap of 4.013 eV. The incorporation of this Cs/Fe2O3 thin film with an optical-based method, i.e., surface plasmon resonance spectroscopy showed positive response where mercury ion (Hg2+) can be detected down to 0.01 ppm (49.9 nM). These results validate the potential of Cs/Fe2O3 thin film for optical sensing applications in Hg2+ detection.

scholarly journals Interactions and Dissociation Constants of Galactomannan Rendered Cellulose Films with Concavalin A by SPR Spectroscopy

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3040
Author(s):  
Pilar Vilaró ◽  
Carina Sampl ◽  
Gundula Teichert ◽  
Werner Schlemmer ◽  
Mathias Hobisch ◽  
...  
Keyword(s):  
Active Sites ◽  
Dissociation Constants ◽  
Resonance Spectroscopy ◽  
Irreversible Adsorption ◽  
Force Microscopy ◽  
Cellulose Films ◽  
The Past ◽  
Physiological Processes ◽  
Atomic Force ◽  
Dissociation Constant Kd

Interactions of biomolecules at interfaces are important for a variety of physiological processes. Among these, interactions of lectins with monosaccharides have been investigated extensively in the past, while polysaccharide-lectin interactions have scarcely been investigated. Here, we explore the adsorption of galactomannans (GM) extracted from Prosopis affinis on cellulose thin films determined by a combination of multi-parameter surface plasmon resonance spectroscopy (MP-SPR) and atomic force microscopy (AFM). The galactomannan adsorbs spontaneously on the cellulose surfaces forming monolayer type coverage (0.60 ± 0.20 mg·m−2). The interaction of a lectin, Concavalin A (ConA), with these GM rendered cellulose surfaces using MP-SPR has been investigated and the dissociation constant KD (2.1 ± 0.8 × 10−8 M) was determined in a range from 3.4 to 27.3 nM. The experiments revealed that the galactose side chains as well as the mannose reducing end of the GM are weakly interacting with the active sites of the lectins, whereas these interactions are potentially amplified by hydrophobic effects between the non-ionic GM and the lectins, thereby leading to an irreversible adsorption.

scholarly journals Scanning speed phenomenon in contact-resonance atomic force microscopy

2018 ◽  
Vol 9 ◽  
pp. 945-952 ◽  
Author(s):  
Christopher C Glover ◽  
Jason P Killgore ◽  
Ryan C Tung
Keyword(s):  
Atomic Force Microscopy ◽  
Hydrodynamic Theory ◽  
Squeeze Film ◽  
Resonance Spectroscopy ◽  
Related Phenomenon ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scan Speed ◽  
Contact Resonance

This work presents data confirming the existence of a scan speed related phenomenon in contact-mode atomic force microscopy (AFM). Specifically, contact-resonance spectroscopy is used to interrogate this phenomenon. Above a critical scan speed, a monotonic decrease in the recorded contact-resonance frequency is observed with increasing scan speed. Proper characterization and understanding of this phenomenon is necessary to conduct accurate quantitative imaging using contact-resonance AFM, and other contact-mode AFM techniques, at higher scan speeds. A squeeze film hydrodynamic theory is proposed to explain this phenomenon, and model predictions are compared against the experimental data.

Sign in / Sign up

Export Citation Format

Share Document