Biodegradable Polymer Films Research Articles

In-situ formation of silver nanoparticles on poly (lactic acid) film by γ-radiation induced grafting of N-vinyl pyrrolidone

A fast, easy and novel method for preparing biodegradable polymer films with silver nanoparticles was investigated to endow the material with excellent biocompatibility and antibacterial property. Silver nanoparticles (Ag NPs) were immobilized on the surface of polylactic acid (PLA) film by gamma radiation induced grafting of N-vinyl pyrrolidone (NVP). In this method, poly (N-vinyl pyrrolidone) (PVP) was produced and grafted onto the surface of PLA film by gamma radiation polymerization of NVP. PVP acted as both a bridge to connect the Ag NPs with the PLA film, and a stabilizer to protect the Ag NPs from agglomeration. The effect of various reaction parameters, including NVP/Ag mole ratio and radiation dose, on the fabrication of PLA-g-NVP/Ag film was demonstrated. Moreover, the interaction between PVP and Ag NPs was studied by X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, that revealed the Ag NPs coordinated through the oxygen atom on the carbonyl group of PVP at 15kGy radiation dose, but through the nitrogen atom and the oxygen atom of the amide group of PVP at 1kGy dose.

Biodegradable Polymeric Films Incorporated with Nisin: Characterization and Efficiency against Listeria monocytogenes

Nisin (0.2 IU per cm2 films) containing biodegradable films were produced from pea protein isolate (PPI), whey protein isolate (WPI), and polylactic acid (PLA). Nisin was released over 4 h at 22 °C and 8 h at 4 °C. PPI released more nisin compared to other films suppressing the growth of Listeria monocytogenes (P < 0.05) based upon diffusion into agar and liquid culture media. The population of bacteria after 48 h in liquid media was 6 CFU/mL (1 log10 increase) in PPI, 8.47 CFU/mL (3.47 log10 increase) in WPI and 9 CFU/mL (4 log10 increase) in PLA, which was significantly lower in protein based films compared to PLA (P < 0.05). The inhibition zone in agar test was significantly higher (P < 0.05) in PPI and WPI, compared to PLA film, which might be due to the higher hydration in protein based films. Fourier transform infrared spectroscopy (FTIR) showed that nisin altered the intensity of amide I peaks in protein based films suggesting that nisin can bind to the protein functional groups in PPI and WPI. Thermogram showed that nisin did not influence the glass transition and melting temperatures of the films. Nisin containing films exhibited significantly lower enthalpy compared to control films (P < 0.05). PeakForce Quantitative Nano Mechanical Property Mapping (PeakForce QNM) was applied to extract material and mechanical properties in PPI, WPI and PLA films with and without nisin. Results showed significant reductions in material and mechanical properties of protein based films containing nisin compared to PLA films.

Mulching materials improve soil properties and maize growth in the Northwestern Loess Plateau, China

Water deficiency is the main limiting factor for crop growth in rain-fed areas. Mulching can affect the soil microclimate (soil water and temperature) and influence the grain yield of crops. A field experiment was conducted to determine the effect of different mulching materials on soil temperature, soil water, crop growth and yield, and water use efficiency (WUE) in spring maize (Zea mays L.) between 2009 and 2011 in Heyang County, Shaanxi, China. The field experiment used five mulch treatments: polyethylene film (PM), biodegradable polymer film (BM), maize straw (MM), liquid membrane (LM), and an uncovered control (CK). In the early stage of maize growth, the topsoil temperatures (0–10cm) in the PM and BM treatments were significantly (P&lt;0.05) higher than CK, whereas the soil temperature in the MM treatment was significantly (P&lt;0.05) lower than CK. The PM, BM, and MM treatments also significantly increased soil water during the early growth stage. However, soil water (0–200cm) in the PM and BM treatments was lower than in the CK treatment during the middle and later growth stages. There was no significant difference (P&gt;0.05) in soil temperature or soil water in the LM treatment during the entire growing season. Maize yield increased significantly (P&lt;0.05) in both the PM and BM treatments by 26.1% and 27.5% during the experimental period compared to the CK treatment. Water use efficiency also significantly increased in these two treatments by 25.1% and 27.6%. These results show that both PM and BM had significant effects on soil temperature, water conservation and maize yield, but no significant (P&gt;0.05) differences were observed between these two treatments. Biodegradable polymer film is useful in reducing environmental pollution caused by polyethylene film and could potentially replace polyethylene film during agricultural production in the Northwestern Loess Plateau, China.

Biodegradable Colour Polymeric Film (Starch-Chitosan) Development: Characterization for Packaging Materials

Biodegradable starch-based chitosan reinforced composite polymeric films were prepared by casting. The chitosan content in the films was varied from 20% to 80% (w/w). Tensile strength (TS) was improved significantly with the addition of chitosan but elongation at break (EB %) of the composites decreased. Tensile strength of the composites raised more with the addition of the acacia catechu content in the films varied from 0.05% to 0.2% (w/w). The better thermal stability of this prepared film was confirmed by thermo-gravimetric analysis. Structural characterization was done by Fourier transform infrared spectroscopy. Surface morphologies of the composites were examined by scanning electron microscope (SEM) which suggested sufficient homogenization of starch, chitosan and acacia catechu. Water uptake was found lower for final composites in comparison to starch/chitosan and chitosan films. The satisfactory rate of degradation in the soil is expected that the final composite film is within less than 6 months. The developed films intended to use as the alternative of synthetic non-biodegradable colored packaging films.

New Biofunctional Loading of Natural Antimicrobial Agent in Biodegradable Polymeric Films for Biomedical Applications.

The study focuses on the development of novel Aloe vera based polymeric composite films and antimicrobial suture coatings. Polyvinyl alcohol (PVA), a synthetic biocompatible and biodegradable polymer, was combined with Aloe vera, a natural herb used for soothing burning effects and cosmetic purposes. The properties of these two materials were combined together to get additional benefits such as wound healing and prevention of surgical site infections. PVA and Aloe vera were mixed in a fixed quantity to produce polymer based films. The films were screened for antibacterial and antifungal activity against bacterial (E. coli, P. aeruginosa) and fungal strains (Aspergillus flavus and Aspergillus tubingensis) screened. Aloe vera based PVA films showed antimicrobial activity against all the strains; the lowest Aloe vera concentration (5%) showed the highest activity against all the strains. In vitro degradation and release profile of these films was also evaluated. The coating for sutures was prepared, in vitro antibacterial tests of these coated sutures were carried out, and later on in vivo studies of these coated sutures were also performed. The results showed that sutures coated with Aloe vera/PVA coating solution have antibacterial effects and thus have the potential to be used in the prevention of surgical site infections and Aloe vera/PVA based films have the potential to be used for wound healing purposes.

Effect of drying chamber for nano-particles embedded bio-degradable polymeric films

Effect of drying chamber for nano-particles embedded bio-degradable polymeric films

Self-Assembled Infrapatellar Fat-Pad Progenitor Cells on a Poly-ε-Caprolactone Film For Cartilage Regeneration.

Cartilage defects resulting from osteoarthritis (OA) or physical injury can severely reduce the quality of life for sufferers. Current treatment options are costly and not always effective in producing stable hyaline cartilage. Here we investigated a new treatment option that could potentially repair and regenerate damaged cartilage tissue. This novel approach involves the application of infrapatellar fat-pad derived chondroprogenitor cells onto a mechanically stable biodegradable polymer film that can be easily implanted into a defect site. Poly-ε-caprolactone (PCL) films were fabricated via solvent casting in either acetone or chloroform. The hydrophobicity, mechanical properties, and surface morphology of the films were examined. Progenitor cells from infrapatellar fat-pad were isolated, expanded, and then seeded onto the films. The cells were allowed to self-assemble on films, and these were then cultured in a chemically defined chondrogenic media for 28 days. The self-assembled tissue was characterized via histological staining, gene expression analysis, immunohistochemistry, and biochemical analysis. Chondrogenic differentiation was induced to generate a cartilaginous matrix upon the films. Despite differences between in the appearance, surface morphology, and mechanical properties of the films cast in chloroform or acetone, both methods produced tissues rich in sulfated glycosaminoglycan and collagen, although the extracellular matrix produced on chloroform-cast films appeared to contain more collagen type II and less collagen type I than acetone-cast films. These self-assembled constructs have the potential to be implanted into defect sites as a potential treatment for cartilage defect regeneration.

Effect of chemical heterogeneity of biodegradable polymers on surface energy: A static contact angle analysis of polyester model films

Biodegradable and bioassimilable poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) derivatives were synthesized and characterized in order to develop a new coating for coronary endoprosthesis enabling the reduction of restenosis. The PDMMLA was chemically modified to form different custom groups in its side chain. Three side groups were chosen: the hexyl group for its hydrophobic nature, the carboxylic acid and alcohol groups for their acid and neutral hydrophilic character, respectively. The sessile drop method was applied to characterize the wettability of biodegradable polymer film coatings. Surface energy and components were calculated. The van Oss approach helped reach not only the dispersive and polar acid–base components of surface energy but also acid and basic components. Surface topography was quantified by atomic force microscopy (AFM) and subnanometer average values of roughness (Ra) were obtained for all the analyzed surfaces. Thus, roughness was considered to have a negligible effect on wettability measurements. In contrast, heterogeneous surfaces had to be corrected by the Cassie–Baxter equation for copolymers (10/90, 20/80 and 30/70). The impact of this correction was quantified for all the wettability parameters. Very high relative corrections (%) were found, reaching 100% for energies and 30% for contact angles.

Holographic gratings recorded in poly(lactic acid)/azo-dye films

Diffraction gratings were recorded in biodegradable polymer films of poly(lactic acid) doped with the photoisomerisable azo-dye (Disperse Orange 3). It is shown that the diffraction efficiency of the recorded grating can be improved by 220% via an all-optical treatment. This all-optical treatment consists of a pre-irradiation of the sample with the writing laser beam at high power during a short period of time, preventing damage of the material, followed by a much longer inscription at relatively low power. Furthermore, it is shown that the addition of a small amount of 0.05wt% of multi-walled carbon nanotubes to the photoresponsive polymer increases the maximum diffraction efficiency as well as the remanent efficiency by 20%. Finally, this last photoresponsive nano-composite is also sensitive to the pre-irradiation treatment.

Comprehensive characterization of polylactide-layered double hydroxides nanocomposites as packaging materials

A series of biodegradable polymeric nano-composite films based on poly(lactic acid) (PLA) and magnesium-aluminum layered double hydroxide (Mg-Al LDH) nano-particles was prepared by solution casting method. Two different Mg-Al LDH nano-fillers at Mg:Al mol ratios of 2:1 and 3:1 were synthesized by co-precipitation technique and to improve the interfacial interaction, the nano-particles were modified by intercalating sodium dodecyl sulfate (SDS) surfactant into the LDH galleries. The PLA nano-composite films, prepared using unmodified (Mg-Al LDH) and modified (SDS-Mg-Al LDH) nano fillers. Both XRD and TEM analyses showed an increasing dispersion and improved exfoliation of SDS-Mg-Al LDH into the PLA matrix. DMA analysis indicated that, at each composition, filler modification resulted in higher storage modulus and Tg. The composite films showed increasing oxygen barrier property up to 23.5 %, compared to PLA. The films containing 5 % of SDS-Mg-Al LDH at Mg:Al ratio of 3:1 exhibited significant increase in oxygen barrier property.

Biodegradable Polymeric Films and Membranes Processing and Forming for Tissue Engineering

AbstractThis paper critically reviews the overall process of biodegradable polymer films and membranes scaffold fabrication for tissue engineering (TE). Various fabrication techniques including both the processing and the post‐processing methods are presented. The processing methods are categorized systematically into basic casting technique, porogen technique, and tooling technique. A comprehensive discussion on post‐processing steps and surface patterning techniques is also included to showcase the potential of membrane in TE applications. This paper also evaluates the requirements of films and membrane scaffolds for specific TE applications. The challenges and future outlook of membrane scaffolds are highlighted with potential application in 3D vascularized tissues fabrication.

Magnetic and transport properties of magneto-anisotropic nanocomposites for controlled drug delivery

Biodegradable polymeric film composites consisting of chitosan (Cht) and poly(3-hydroxybutyrate) (PHB) have been produced and used to encapsulate colloidal magnetite nanoparticles (MNPs) and a drug (dipyridamole). The magnetic organization of the MNPs induced by the exposure of the films to external magnetic fields was analyzed using ferromagnetic resonance and electron microscopy. A calculation of the relative abundance of aggregated nanoparticles showed that more than 14% of the particles were aggregated at total particle concentrations ranging from 3 to 8 mass %. Modification of the PHB-Cht composite matrix by nanoparticles has been proven to evoke changes in drug release kinetics, since the particles formed ordered magneto-anisotropic structures when exposed to external magnetic fields. The highest rate of transfer by diffusion was observed in the case of a nonisotropic matrix in which the orientation of particle aggregates coincided with the direction of the diffusion flux; the rate of drug release was the lowest in anisotropic matrices of biodegradable magneto-anisotropic nanocomposites with particle orientation perpendicular to the direction of diffusion. The physical reasons for the dependence of the release kinetics on the magnetic anisotropy of the samples are discussed. The results of the present study are indicative of the possibility of creating a new generation of therapeutic systems for the targeted delivery and sustained release of drugs controlled by a magnetic field.

Fabrication and characterization of biodegradable polymeric films as a corneal stroma substitute.

Background:Biodegradable elastomeric materials such as poly glycerol sebacate (PGS) have gained much current attention in the field of soft tissue engineering. The present study reports the synthesis of PGS with molar ratios of 1:1, 2:3, and 3:2 of glycerol and sebacic acid via polycondensation reaction and tests the effect of PGS on human corneal epithelial (HCE) cells viability in vitro.Materials and Methods:PGS films were prepared by the casting method. We tried to fabricate PGS with different compositions and various properties as being a viable alternative to the corneal stroma in cornea tissue engineering. The chemical properties of the prepared polymer were investigated by means of attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR) analysis and the in vitro cytotoxicity was investigated by the Alamarblue method.Results:The functional groups observed in the PGS FTIR spectrums of PGS with various molar ratios were the same. However, the main difference was the time of completing the cross-linking reaction. The PGS prepared by 2:3 ratio as a molar ratio had the fastest and the 3:2 ratio had the lowest cross-linking rate because of the higher amount of sebacic acid. Results of the Alamarblue cytotoxicity test assay showed no deleterious effect on HCE cell viability and proliferation.Conclusions:PGS is a potentially good candidate material for corneal tissue engineering because of its lack of in vitro HCE cell toxicity.

Physico-mechanical characterization and biodegradability behavior of polypropylene/poly(L-lactide) polymer blends

Abstract Partially biodegradable polymer films from the blends of polypropylene (PP) and poly(L-lactide) (PLLA) were prepared in an internal mixer by melt blending technique, with and without compatibilizer, maleic anhydride grafted polypropylene (MAPP), followed by compression molding. With regard to tensile properties, 80/20 (PP/PLLA) and 80/20/6 (PP/PLLA/MAPP) were found as the optimum blends with best combination of the ingredients. Therefore, the blend samples, namely, PP80 (80% PP+20% PLLA) and PP80C6 (80% PP+20% PLLA+6 phr MAPP) were selected as ‘optimized’ blends and further characterized for their physical, chemical, morphological, and thermal properties. X-ray diffraction studies showed that neat PP and PP80C6 had the same crystallite size indicating compatibility between PP and PLLA due to MAPP. Fourier transform infrared spectroscopy and scanning electron microsopy investigations revealed that the two polymers were completely immiscible in absence of the compatibilizer. Bacterial biodegradation of the samples was performed by exposure to Pseudomonas stutzeri for 60 days and measured in terms of weight loss, optical density, and thermal stability of the samples before and after degradation. The results showed that 80/20 (PP/PLLA) blends undergo considerable degradation. Reduction in thermal stability of the film samples was also observed through thermogravimetric analysis, which was useful in accelerating their biodegradation.

Ориентационная вытяжка как фактор, влияющий на деградацию биоразрушающихся смесевых полимерных пленок

Ориентационная вытяжка как фактор, влияющий на деградацию биоразрушающихся смесевых полимерных пленок

Preparation and Characterization of Potentially Antimicrobial Polymer Films Containing Starch Nano- and Microparticles

The forming conditions of biodegradable polymer films containing iodine-modified starch particles as well as the properties of the obtained films were investigated. Cationic cross-linked starch microparticles and cationic starch nanoparticles were dispersed in cellulose acetate and hydroxyethyl cellulose solution, respectively, and composite films were spin-casted. The obtained films were characterized and their mechanical properties were assessed. The cellulose acetate solution has been found to be an appropriate matrix for the dispersion of dry modified starch microparticles, but not in the case of nanoparticles. Starch nanoparticles were obtained in an aqueous medium, and the mechanical properties of the formed cellulose acetate films are significantly reduced by water present in the casting solution. It has been estimated that a fairly high amount of nanoparticles (18 wt%) can be immobilized into films of water-soluble hydroxyethyl cellulose without markedly affecting the mechanical properties of the films. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.5426

Effects of small intestinal submucosa content on the adhesion and proliferation of retinal pigment epithelial cells on SIS-PLGA films.

The retinal pigment epithelium (RPE) plays a critical role in the maintenance of the normal functions of the retina, particularly the photoreceptors. RPE dysfunction, vision loss and degeneration have been implicated as the cause of many retinal diseases, including retinitis pigmentosa and age-related macular degeneration (AMD). To overcome such disorders, tissue engineering could offer useful strategies, using biodegradable polymeric films to replace diseased or lost RPE. Synthetic/natural hybrid films have been studied as a temporary substrate for growing RPEs in biological implantations. In this study, we prepared small intestinal submucosa (SIS)-poly(lactic-co-glycolic) (PLGA) hybrid films and seeded human RPE cells (ARPE-19 cells) onto the film surface. We investigated the film suitability for RPE cell proliferation by MTT assay. The morphology of cellular adhesion on the film was confirmed by scanning electron microscopy (SEM). Reverse transcription-polymerase chain reaction (RT-PCR) and 3-amino-9-ethylcarbazole (AEC) staining were performed to examine mRNA expression and to compare cell proliferation on the films, using cytokeratin as a marker of RPE. Conclusively, we confirmed the higher cell survival rate and much stronger phenotype expression of RPEs on SIS-PLGA films compared to pure PLGA films. These results demonstrated the potential application of SIS-PLGA films in tissue-engineering strategies. Copyright © 2014 John Wiley & Sons, Ltd.

Matrix Metalloproteinase 9 (MMP-9) Mediated Release of MMP-9 Resistant Stromal Cell-Derived Factor 1α (SDF-1α) from Surface Modified Polymer Films

Preparation of smart materials by coatings of established surfaces with biomolecules will lead to the next generation of functionalized biomaterials. Rejection of implants is still a major problem in medical applications but masking the implant material with protein coatings is a promising approach. These layers not only disguise the material but also equip it with a certain biological function. The anti-inflammatory chemokine stromal cell-derived factor 1α (SDF-1α) is well suited to take over this function, because it efficiently attracts stem cells and promotes their differentiation and proliferation. At least the initial stem cell homing requires the formation of a concentration gradient. Thus, a reliable and robust release mechanism of SDF-1α from the material is essential. Several proteases, most notably matrix metalloproteinases, are upregulated during inflammation, which, in principle, can be exploited for a tightly controlled release of SDF-1α. Herein, we present the covalent immobilization of M-[S4V]-SDF-1α on novel biodegradable polymer films, which consist of heterobifunctional poly(ethylene glycol) and oligolactide-based functionalized macromers. A peptidic linker with a trimeric matrix metalloproteinase 9 (MMP-9) cleavage site (MCS) was used as connection and the linkage between the three components was achieved by combination of expressed protein ligation and Cu(I) catalyzed azide/alkyne cycloaddition. The MCS was used for MMP-9 mediated release of M-[S4V]-SDF-1α from the biomaterial and the released SDF-1α derivative was biologically active and induced strong cell migration, which demonstrates the great potential of this system.

Three-Dimensional Quadratic Model of Paclitaxel Release from Biodegradable Polymer Films

This paper presents a three-dimensional (3D) quadratic partial differential equation model of the drug release from a thin film of biodegradable polymer to a surrounding medium. Its very innovative feature is to go directly from the experimental normalized release curves of Lao and Venkatraman [J. Control. Release, 130 (2008), pp. 9--14] to a flux condition at the interface between the polymer and the medium that only requires the identification of the two parameters of the highly accurate ordinary differential equation model of Blanchet, Delfour, and Garon [SIAM J. Appl. Math., 71 (2011), pp. 2269--2286]. In the context of drug eluting stents, it is a practical and economical tool to theoretically and numerically simulate the 3D release of drug from the thin polymer film to the integrated wall and lumen of the blood vessel for evaluation and design. This approach avoids resorting to time-dependent or nonlinear diffusion in the polymer.

Cenderitide-Eluting Film for Potential Cardiac Patch Applications

Cenderitide, also known as CD-NP, is a designer peptide developed by combining native mammalian c-type natriuretic peptide (CNP) and the C-terminus isolated from the dendroapis natriuretic peptide (DNP) of the venom from the green mamba. In early studies, intravenous and subcutaneous infusion of cenderitide was reported to reduce left ventricular (LV) mass and ameliorate cardiac remodelling. In this work, biodegradable polymeric films encapsulating CD-NP were developed and were investigated for their in vitro release and degradation characteristics. Subsequently, the bioactivity of released peptide and its effects on human cardiac fibroblast (HCF) were explored. We achieved sustained release from three films with low, intermediate and high release profiles for 30 days. Moreover, the bioactivity of released peptide was verified from the elevated production of cyclic guanosine monophospate (cGMP). The CD-NP released from films was able to inhibit the proliferation of hypertrophic HCF as well as suppress DNA synthesis in HCF. Furthermore, the sustained delivery from films showed comparable or superior suppressive actions on hypertrophic HCF compared to daily infusion of CD-NP. The results suggest that these films could be used to inhibit fibrosis and reduce cardiac remodelling via local delivery as cardiac patches.