Layer-by-Layer Film Growth Using Polysaccharides and Recombinant Polypeptides: A Combinatorial Approach (original) (raw)
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International Journal of Food Science & Technology, 2007
This study assessed the film-forming abilities of six types of proteins, as well as six types of polysaccharides at various concentrations (proteins: 0-16%; polysaccharides: 0-4%) and heating temperatures (60-80°C). Biopolymer films evaluated included: sodium caseinate (SC), whey protein isolate (WPI), gelatine (G); caboxymethyl cellulose (CMC), sodium alginate (SA) and potato starch (PS). Screening trials showed that optimal film-forming conditions were achieved using SC and G (4% and 8%), WPI (8% and 12%), PS, CMC (2% and 3%) or SA (1% and 1.5%) solutions heated to 80°C in combination with 50% (w/w) glycerol. Films manufactured from 1.5% SA, 8% G and 3% CMC had the highest tensile strength (24.88 MPa); flexibility (89.69%)/tear strength (0.30 N) and puncture resistance (22.66 N), respectively. SC, WPI and G-based films were more resistant to solvent than SA, CMC and PS. Film permeability to water vapour and oxygen decreased in the order: 12% WPI to 1% SA and 12% WPI to 1% SA. All films tested were impermeable to oil.
Biopolymer films synthesis and characterisation
Journal on Processing and Energy in Agriculture
In this study, three biopolymer films were synthesized: zein (protein), gelatin (protein), and starch (polysaccharide) films and characterized by determining mechanical and physico-chemical properties. Gelatin films proved to be the strongest (tensile strength 84 N/15 mm), while the zein were most flexible (elongation at break 41.6 %). Moisture content was higher in starch films, which is a result of the hydrophilic nature of the polysaccharide films. Swelling degree was 22.5 % for zein, 90.9 % for gelatin, while the highest average value was recorded in starch film samples (840.6 %). Starch films had highest value of solubility degree (36.5 %), while zein film had 27.9 % and gelatin film had 11.85 %.Obtained characterization results are consequences of the different structure of the raw materials and synthesis routes. All undesirable characteristics could be improved by optimizing the composition of the film, as well as synthesis of composite/laminated films.
Ion Pairing and Hydration in Polyelectrolyte Multilayer Films Containing Polysaccharides
Biomacromolecules, 2009
Thin films constituted of poly(L-lysine) (PLL) as polycation and of the anionic polysaccharides hyaluronan (HA), chondroitin sulfate (CSA), and heparin (HEP) as polyanions with increasing sulfate contents have been investigated for their internal structure, including water content and ion pairing. Film buildup in physiological solutions was followed in situ by quartz crystal balance with dissipation monitoring (QCM-D) and attenuated total internal reflectance (ATR-FTIR), infrared spectroscopy (ATR-FTIR), which allows an unambiguous quantification of the groups (sulfate, carboxylate, ammonium) present on the side groups of the polyelectrolytes. HA-and CSA-based films were the most hydrated ones. The monomer ratio (disaccharide/lysine) was very similar for all the films, whatever the polyanion, and tended toward a plateau value at ∼0.5, indicating that there are two lysine molecules per disaccharide monomer. Thanks to the possibility to selectively cross-link carboxylate and ammonium ions via carbodiimide chemistry, the COO -/NH 3 + and SO 3 -/NH 3 + ion pairing was determined. We found that 46% of NH 3 + groups are unpaired (i.e., extrinsically compensated by counterions) in HA-based films, 21% in CSA-based films and none in HEP ones, which is indeed in agreement with fluorescence recovery after photobleaching (FRAP) measurements of fluorescently labeled PLL diffusion in the films. In addition, the ratio of SO 3 versus COOpairing with NH 3 + groups was close to the stoechiometry of these groups in the dissacharide monomeric unit, that is, 2:1 for HEP-based films and 1:1 for CSA based films. Thus, hydration, ion pairing, and PLL diffusion in the films are interconnected properties that arise from the specific structures of the biomacromolecules constituting the films.
Layer by Layer Buildup of Polysaccharide Films: Physical Chemistry and Cellular Adhesion Aspects
Langmuir, 2004
The formation of polysaccharide films based on the alternate deposition of chitosan (CHI) and hyaluronan (HA) was investigated by several techniques. The multilayer buildup takes place in two stages: during the first stage, the surface is covered by isolated islets that grow and coalesce as the construction goes on. After several deposition steps, a continuous film is formed and the second stage of the buildup process takes place. The whole process is characterized by an exponential increase of the mass and thickness of the film with the number of deposition steps. This exponential growth mechanism is related to the ability of the polycation to diffuse "in" and "out" of the whole film at each deposition step. Using confocal laser microscopy and fluorescently labeled CHI, we show that such a diffusion behavior, already observed with poly(Llysine) as a polycation, is also found with CHI, a polycation presenting a large persistence length. We also analyze the effect of the molecular weight (MW) of the diffusing polyelectrolyte (CHI) on the buildup process and observe a faster growth for low MW chitosan. The influence of the salt concentration during buildup is also investigated. Whereas the CHI/HA films grow rapidly at high salt concentration (0.15 M NaCl) with the formation of a uniform film after only a few deposition steps, it is very difficult to build the film at 10 -4 M NaCl. In this latter case, the deposited mass increases linearly with the number of deposition steps and the first deposition stage, where the surface is covered by islets, lasts at least up to 50 bilayer deposition steps. However, even at these low salt concentrations and in the islet configuration, CHI chains seem to diffuse in and out of the CHI/HA complexes. The linear mass increase of the film with the number of deposition steps despite the CHI diffusion is explained by a partial redissolution of the CHI/HA complexes forming the film during different steps of the buildup process. Finally, the uniform films built at high salt concentrations were also found to be chondrocyte resistant and, more interestingly, bacterial resistant. Therefore, the (CHI/HA) films may be used as an antimicrobial coating.
Mono- and bilayer biopolymer films: Synthesis and characterisation
Journal on Processing and Energy in Agriculture
The purpose of this paper is to improve the properties of biopolymer protein monofilms and produce a novel bilayer biopolymer film on the basis of the monofilms analyzed. Biopolymer monolayer films, based on pumpkin oil cake (PuOC) and zein, and a bilayer film, based on PuOC and zein (PuOC/Zein), were produced as a result of the study. The visual, mechanical, physicochemical and structural properties of the films were evaluated. The results obtained showed that the PuOC film exhibited the highest elongation at break, followed by the bilayer film, whereas the zein film showed the lowest elongation at break. However, the zein film showed the highest tensile strength, followed by the PuOC film. The tensile strength of the bilayer PuOC/Zein film was almost 3 times lower than that of the PuOC film, and almost 4 times lower than that of the zein film. The physicochemical properties recorded indicate that the hydrophobic zein film is the least sensitive to moisture, affecting the moisture sensitivity of PuOC film by reducing the moisture content, swelling and total soluble mater of the bilayer PuOC/Zein film. Based on the FTIR spectra, it could be concluded that there are no significant differences between the two sides of the bilayer PuOC/Zein film. Both sides of the bilayer film examined indicated characteristic peaks for protein biopolymer films in the FTIR spectrum.
Materials Science and Engineering: C, 2015
There is an increasing interest in the use of polysaccharides and proteins for the production of biodegradable films. Visible and near-infrared (VIS-NIR) spectroscopy is a reliable analytical tool for objective analyses of biological sample attributes. The objective is to investigate the potential of VIS-NIR spectroscopy as a process analytical technology for compositional characterization of biodegradable materials and correlation to their mechanical properties. Biofilms were produced by single-screw extrusion with different combinations of polybutylene adipate-co-terephthalate, whole oat flour, glycerol, magnesium stearate, and citric acid. Spectral data were recorded in the range of 400-2498 nm at 2 nm intervals. Partial least square regression was used to investigate the correlation between spectral information and mechanical properties. Results show that spectral information is influenced by the major constituent components, as they are clustered according to polybutylene adipate-co-terephthalate content. Results for regression models using the spectral information as predictor of tensile properties achieved satisfactory results, with coefficients of prediction (R 2 C) of 0.83, 0.88 and 0.92 (calibration models) for elongation, tensile strength, and Young's modulus, respectively. Results corroborate the correlation of NIR spectra with tensile properties, showing that NIR spectroscopy has potential as a rapid analytical technology for non-destructive assessment of the mechanical properties of the films.
Biomacromolecules, 2011
Polyelectrolyte multilayers using the polycations chitosan and N,N,N-trimethyl chitosan and the polyanions hyaluronan, chondroitin sulfate, and heparin are studied. Chitosan and hyaluronan behave as a weak polycation and weak polyanion, respectively, whereas N,N,N-trimethyl chitosan, chondroitin sulfate, and heparin behave as strong polyelectrolytes. Hydrophilicity is determined by water contact angle measurements and by comparing wet and dry film thickness measurements. Wet thickness is obtained using Fourier transform surface plasmon resonance, whereas dry thickness is obtained through ellipsometry. For the very thin PEMs studied here, the surface hydrophilicity and swelling in water are highly correlated. The multilayer chemistry is assessed by FT-IR and X-ray photoelectron spectroscopy (XPS). FT-IR and XPS provide information about the composition, degree of ionization, and by inference, the ion pairing. We find that hydrophilicity and swelling are reduced when one polyelectrolyte is strong and the other is weak, whereas ion pairing is increased. By this combination of techniques, we are able to compose a unified description of how the PEM swelling is dictated by the ion pairing in thin polysaccharide-based PEMs.
Mechanical Strength, Solubility, and Functional Studies of Developed Composite Biopolymeric Film
Journal of Food Processing and Preservation
The study evaluated the use of corn, quinoa, and tapioca starches with glycerol to develop biopolymer films. The water binding and oil binding capacities of the starches were determined, and tapioca starch was found to have good film-forming properties and produce transparent films. During the study, starches and glycerol with concentrations of 6% w / v and 3% w / v respectively, were used to develop the biopolymer films. These starches were evaluated for water binding and oil binding, with capacities that ranged from 182.62 to 199.60% and 159.02 to 193.33%, respectively. Quinoa starch presented the highest final viscosity (3584.00 cP), followed by corn starch (3058.00 cP) and tapioca starch (2547.00 cP), which indicate that these starches possess an intermediate range of viscosities required for the development of biopolymeric films. Comparative studies of the properties of starches were done with the intention of developing better quality films among corn, quinoa, and tapioca star...
Polysaccharide-based polyelectrolyte multilayers
2010
In recent years, the layer-by-layer technique has grown in various fields. One of the emerging trends of bioapplications is the use of polysaccharides as main film components, which stems from their intrinsic physical, chemical and biological properties. These allow the simple formation, by self-assembly, of new kinds of mimics of extra-cellular matrices from plant and animal tissues. These assemblies, which possess specific properties arising from their hydration and internal composition, can indeed contain additional functionalities obtained by chemical modification of the biopolymers or film post-processing. They can be molded into different forms (films, membranes, and capsules).