PLA Concentrations Research Articles

Preparation of nylon 6/PLA blend nanofibers by needleless electrospinning

The nylon 6/PLA blend nanofibers have been prepared for the first time by needleless electrospinning. The formic acid (FA) was found to be the co-solvent with dichloromethane (DCM) at a ratio of 3:1 for dissolving nylon 6/PLA blend. The nylon 6/PLA blend solutions in various ratios of PLA (8, 10, and 12 wt%) were studied to prepare nanofiber at the applied voltage range of 25 kV to 30 kV. The morphology images of the fibers were shown by scanning electron microscope (SEM). It was found that the average diameter of the nylon 6/PLA blend fibers became smaller as the applied voltage increased from 25 kV to 30 kV and as the PLA content increased from 8 to 12 wt%. The morphology of the fibers became finer with increasing the PLA content. The morphology of the nylon 6:PLA (20:10) nanofibers presented a smooth surface without the formation of beads with an average diameter of 157 nm at the applied voltage of 25 kV. The high PLA content (12 wt%) at a low applied voltage (25 kV) exhibited the bead formation. In contrast, the bead was formed at the medium PLA concentration (10 wt%) at the applied voltage of 30 kV. Therefore, the high PLA content (12 wt%) at a high applied voltage (30 kV) presented a ribbon-like nanofiber of nylon 6/PLA without bead formation. The particle size distribution obtained from SEM images of the nylon 6/PLA nanofiber was narrow at low PLA contents and became broader at higher PLA concentrations.

Raspberry-like PLA/PGS biodegradable microparticles with urethane linkages: Unlocking tailored release of magnesium ions and oxygen for bone tissue engineering

Designing biodegradable microparticles with finely controlled release properties for tissue engineering systems remains a significant scientific challenge. This study introduces a novel approach by fabricating urethane-linked PLA/PGS microparticles loaded with magnesium peroxide. The microparticles offer potential applications in bone tissue engineering due to their ability to provide a controlled release of oxygen and magnesium ions while maintaining physiological pH. The PGS pre-polymer was synthesized via polycondensation and characterized using FTIR, 1H NMR, and GPC. Microparticle morphology transformed from smooth to raspberry-like upon incorporation of PGS, as observed by SEM. Microparticle size was tuned by varying PGS and PLA concentrations. FTIR analysis confirmed the successful formation of urethane links within the microparticles. MgO2-loaded PLA/PGS microparticles exhibited sustained release of dissolved oxygen and magnesium ions for 21 days while maintaining physiological pH better than PLA microparticles. Cell viability assays confirmed microparticle cytocompatibility, and ALP and Alizarin red assays demonstrated their ability to induce osteogenic differentiation. These findings highlight the potential of pH-controlled MgO2-loaded microparticles as an effective system for bone tissue engineering. In conclusion, this study presents a novel approach to designing biodegradable microparticles with adjustable release properties for bone tissue engineering. The urethane-based MgO2-loaded microparticles provide controlled release of oxygen and magnesium ions and regulate the environment’s pH, making them a promising system for bone tissue engineering applications.

The interaction effects of biodegradable microplastics and Cd on Folsomia candida soil collembolan.

In real-field soil conditions, multiple chemicals exposure may be the real scenario for soil biota. The co-occurrence of microplastics (MPs) and cadmium (Cd) is common in soils, which may pose a potential risk to soil ecosystems. Degradable microplastics are producing more MPs, and the potential effects on soil ecosystems are unknown. Therefore, a standard soil animal collembolan Folsomia candida was used to evaluate the single and interaction effects of biodegradable MPs (PLA) and Cd. The results showed that single and co-biodegradable PLA and Cd all had negative influences on the survival, reproduction, and growth of F. candida, and the effects intensified with PLA concentrations. The survival rate, reproduction rate, adult body length, and juvenile body length decreased by 20.0%, 24.2%, 22.9%, and 32.2% at MPs-100 treatment. But combined PLA and Cd alleviated the toxicity of single Cd on F. candida at lower PLA concentrations. The number of juveniles increased by 29.3%, the survival rate increased by 7.52%, the adult body length increased by 11.7%, and the juvenile body length increased by 19.0% at MPs-1 + Cd than single Cd treatment. Biochemical assays on antioxidant enzymes had the same results. Antioxidant enzymes CAT and POD were more sensitive than SOD. CAT and POD activities were induced quickly at shorter exposure periods, and MP treatment thus may be promising biomarkers on soil collembolan for soil MP exposure. PLA is degraded with time in soils; therefore, the long-term effects of co-MPs and Cd in soils are suggested to be further studied.

Investigation of the candesartan cilexetil antihypertensive drug microencapsulation by PLA‐PVP K30 biodegradable polymers: Experimental optimization and release kinetics modelling

AbstractCandesartan is an angiotensin receptor blocker (ARB) used to treat hypertension. However, its poor aqueous solubility and oral bioavailability have limited its therapeutic applications. In order to increase bioavailability and control the release of candesartan condensation, microspheres containing biodegradable polymers (polyvinylpyrrolidone [PVP K30] and polylactic acid [PLA]) in different ratios were prepared by the o/o solvent evaporation method using Span 80 as a surfactant. In addition, the impact of encapsulation parameters (i.e., PVP K30 and PLA concentrations) on the encapsulation ratio and release percentage was investigated by the mixed factorial design method. The release kinetics of the microspheres was simulated by combining two methods, the Dragonfly algorithm and a support vector machine (DA‐SVM). The experimental data were in good agreement with the predicted data, with a coefficient of determination close to unity and a mean square error close to zero. Fourier‐transfer infrared spectrometry (FTIR) analysis revealed the presence of condensation in all formulations without reporting distortion in the spectra. Scanning electron microscopy (SEM) confirmed the successful synthesis of microspheres, whose sizes were between 12 and 26 μm. Formulations with a PLA‐drug ratio of 6:1 (N15, N17, and N18) showed the highest encapsulation efficiency (68%, 71%, and 70%, respectively), while formulations that do contain PVP K30, such as N5, N4, and N3, showed a higher release (83%, 84%, and 89%, respectively), indicating that the agent (PVP K30) enhanced the bioavailability and release of candesartan. Overall, N3 showed a higher drug release rate at 12 h and important encapsulation efficiency, making it the optimal formulation obtained in this study.

Electrospraying poly(lactic acid) microcapsules loaded with n-hexadecane for thermal energy storage systems

Poly(lactic acid) (PLA) with good thermomechanical stability and biodegradability is selected as the shell for achieving the electro-microencapsulation of phase change materials. And, a series of n-hexadecane/PLA solutions with different compositions are electrosprayed into phase change microcapsules (mPCMs) in a green and high-efficiency way. The effects of PLA concentration and n-hexadecane addition in electrospraying solution on the microencapsulation process of n-hexadecane as well as the structures and properties of mPCMs are investigated. Experimental results indicate that spherical mPCMs with a mono-dispersed size distribution are obtained regardless of the variations in PLA concentrations and n-hexadecane additions. Encapsulated n-hexadecane tends to be randomly in the form of a poly-nuclear distribution. With increasing n-hexadecane addition, although both the mean diameter and the loading content of n-hexadecane in mPCMs increase gradually, the corresponding encapsulation efficiency of n-hexadecane decreases. And, higher loading content and higher encapsulation efficiency of n-hexadecane are obtained from higher PLA concentration solutions. When 5 wt% PLA/chloroform solution is used as matrix liquid to encapsulate n-hexadecane, the encapsulation efficiency of n-hexadecane in the mixture of 50 w/t% n-hexadecane and 50 wt% PLA can reach about 100%. Correspondingly, the phase-transition enthalpy also reaches 97 J/g. Meanwhile, because of the PLA matrix's protection, the phase-transition enthalpy of encapsulated n-hexadecane remains stable even after multiple heating-cooling processes. In addition, the cooperation of the PLA matrix with n-hexadecane chains also improves the mobility of PLA chains, resulting in a higher crystallization degree of the PLA matrix. This green, biodegradable, and durable n-hexadecane/PLA electrosprayed microcapsule can offer a new choice for the fields of thermal management and energy storage.

Fabrication of fully degradable branched poly (lactic acid) nanofiber membranes for high‐efficiency filter paper materials

AbstractAir pollution caused by particulate matter (PM) poses an imminent threat to the global environment and public health. However, balancing the removal efficiency and pressure drop of most filter materials is difficult. Moreover, filter materials are non‐degradable and non‐recyclable, causing serious harm to the environment. Herein, a strategy to create fully degradable branched poly (lactic acid) (PLA) nanofibers based on electrospinning by adjusting the spinning solution properties was reported and branched PLA nanofibers were applied as nanofiber filter paper for air filtration materials. When the PLA and tetrabutylammonium chloride concentrations were 8 and 5 wt%, respectively, PLA nanofibers with branched structures were obtained. The obtained nanofibers possessed a small pore size (0.70 μm), high porosity (92.3%), appropriate mechanical properties, resulting in high PM0.3 removal efficiency (99.95%), low air resistance (79.67 Pa), and promising long‐term PM2.5 purification. Notably, branched T‐PLA‐5 nanofibers exhibited excellent filtration performance when applied to cellulose wood pulp paper. The filtration efficiency of the nanofiber filter paper remained stable above 85% for PM0.3 (32 L min−1) after 5000 backflushings. Thus, the preparation of such nanomaterials may provide new insights into the design and development of high‐performance degradable filtration materials for various applications.

Preparation and characterization of gelatin/chitosan/3-phenylacetic acid food-packaging nanofiber antibacterial films by electrospinning

In this study, antibacterial nanofiber films were prepared by electrospinning gelatin, chitosan, and 3-phenyllactic acid (PLA). The addition of PLA improved the microstructures of the nanofibers, and the nanofiber films (GCP-1 and GCP-2) had uniform and continuous structures with a diameter range of 40‐–70 nm when the PLA concentrations in the polymers were 1% and 2%. Under acidic conditions, chitosan and PLA interacted and formed hydrogen bonds, which decreased the crystallinity of the nanofiber films. The GCP-2 nanofiber film had the best thermal stability, water stability, and water vapor permeability. Compared with the control GCP-0 film, the four nanofiber films with PLA (GCP-1, GCP-2, GCP-3, and GCP-4) had more effective antibacterial effects, and GCP-2 film reduced approximately 4 log CFU/mL of Salmonella enterica Enteritidis and Staphylococcus aureus in 30 min. Results suggested that the GCP-2 nanofiber film mat can be used as an active food packaging.

Electrospun drug blended poly(lactic acid) (PLA) nanofibers and their antimicrobial activities

In the present study, the influence of electrospinning parameters on poly(lactic acid) (PLA) nanofiber production and antimicrobial attitude of drug blending were investigated. The PLA concentrations (5 to 12% wt/v) were determined with solvent ratio variations of a triple solvent system (chloroform (CHL), dimethylformamide (DMF) and tetrahydrofuran (THF)). Flow rates were varied from 0.5 to 1 mL/h, while voltages were changed from 10 to 15 kV, and 10 kV voltage and 0.5 mL/h flow rate were selected as optimum electrospinning conditions. According to morphological investigations via scanning electron microscopy, the average PLA fiber diameters varied from 303 to 405 nm, for 5 and 8% wt/v PLA concentrations, respectively. The drug (ceftriaxone disodium) was blended into these concentrations and electrospun. Drug addition reduced the fiber diameters, and at 8% wt/v drug blended PLA concentrations homogeneous fiber distribution was obtained. Additionally, the antimicrobial attitude of drug blended PLA nanofibers was analyzed by using agar disc diffusion method and antimicrobial activity against Escherichia coli, and Listeria monocytogenes were observed.

Investigation of electrohydrodynamic atomization (electrospraying) parameters’ effect on formation of poly(lactic acid) nanoparticles

The aim of this study was to develop nanoparticles via electrohydrodynamic atomization (electrospraying) method. These nanoparticles have potential applications such as drug delivery and manipulating surface functionality. Electrosprayed nanoparticles were produced from poly(lactic acid) (PLA). Solution and process parameters were investigated for optimization of the electrospraying process. Different PLA concentrations, solvent types and solvent ratios were investigated as part of the study. The characterization of the electrosprayed solutions was carried out via viscosity, conductivity and surface tension measurements. Also, the effect of process parameters (flow rate, needle to collector distance, electrical field, application time and needle dimension) on particle morphology and dimension was investigated. After the formation of PLA nanoparticles, morphological and dimensional characteristics were analyzed through SEM images and nanosizer measurements. According to some of our findings, particle size increases with higher polymer concentrations and flow rates. Also, increase in electrostatic field and distance result in smaller particle size because of increase in coulombic forces. But a further increase in coulombic forces triggers increase in size of particles and fibril formation with a bimodal distribution. The smallest size and the narrowest distribution were obtained for the smallest inner needle diameter. Deposition time does not have a significant influence on the produced particle sizes and their distributions; it only affects the production amount. As a result of this study, desired monodisperse PLA nanoparticles with comparatively smaller size were successfully achieved. Also, the detailed investigation of electrospraying parameters can be useful for future studies.

PLA Electrospun Scaffolds for Three-Dimensional Triple-Negative Breast Cancer Cell Culture.

Three-dimensional (3D) systems provide a suitable environment for cells cultured in vitro since they reproduce the physiological conditions that traditional cell culture supports lack. Electrospinning is a cost-effective technology useful to manufacture scaffolds with nanofibers that resemble the extracellular matrix that surround cells in the organism. Poly(lactic acid) (PLA) is a synthetic polymer suitable for biomedical applications. The main objective of this study is to evaluate electrospun (ES)-PLA scaffolds to be used for culturing cancer cells. Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with no validated targeted therapy and a high relapse rate. MDA-MB-231 TNBC cells were grown in scaffolds from two different PLA concentrations (12% and 15% w/v). The appropriateness of ES-PLA scaffolds was evaluated using a cell proliferation assay. EGFR and STAT3 gene expression and protein levels were compared in cells grown in 2D versus in 3D cultures. An increase in STAT3 activation was shown, which is related to self-renewal of cancer stem cells (CSCs). Therefore, the enrichment of the breast CSC (BCSC) population was tested using a mammosphere-forming assay and gene expression of BCSC-related stemness and epithelial-to-mesenchymal transition markers. Based on the results obtained, ES-PLA scaffolds are useful for 3D cultures in short culture periods with no BCSC-enrichment.

Prediction of storage modulus in solid-like poly (lactic acid)/poly (ethylene oxide)/carbon nanotubes nanocomposites assuming the contributions of nanoparticles and interphase regions in the networks.

In this paper, Kolarik model for tensile modulus of co-continuous blends is developed to predict the storage modulus of poly (lactic acid) (PLA)/poly (ethylene oxide) (PEO)/carbon nanotubes (CNT) nanocomposites at low frequencies (solid-like region). The storage moduli of prepared samples are obtained by frequency sweep test and Kolarik model is expanded assuming the characteristics of interphase regions and CNT networks. The developed model takes into account the percolation threshold, the percentage of networked CNT and the volume fraction of interphase regions in the networks. The calculations of developed model are compared to the experimental data and the significances of main parameters on the storage modulus are justified. The calculations successfully agree with the experimental data at different PLA and CNT concentrations. The addition of CNT thickens and strengthens the interphase regions in the samples, but the different concentrations of PLA differently affect the properties of interphase regions. A thick and strong interphase enhances the storage modulus of nanocomposites. The high fraction of networked CNT and the significant modulus of nanoparticles considerably promote the storage modulus, but only small networks cause poor storage modulus for nanocomposites.

Ionic Liquid Platform for Spinning Composite Chitin–Poly(lactic acid) Fibers

In the design of stronger chitin fibers reinforced with poly(lactic acid) (PLA), an ionic-liquid-based (IL-based) approach was developed in which both polymers were codissolved in an 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) and wet-jet spun into composite fibers. Chitin, directly extracted from shrimp shell, had a solubility in the IL of 2.75 wt %, while PLA of MW 700 000 g/mol had a solubility of 49 wt %. Keeping the IL saturated in chitin, homogeneous solutions of chitin and PLA could be obtained up to 27 wt % (relative to the IL) PLA. Spinning dopes were prepared by maintaining the chitin concentration relative to the IL at 1.75 wt % and adding PLA in chitin to PLA weight ratios of 1:0.1 through 1:1 (PLA concentrations of 0.175–1.75 wt % relative to the IL). Homogeneous chitin/PLA fibers could be spun when the chitin to PLA ratio was between 1:0.1 and 1:0.3. The tensile strength and plasticity of the fibers depended on the chitin to PLA ratio with the highest plasticity (8.8% vs 3.0% for pure...

Development of poly (lactic acid) microspheres and their potential application in Pickering emulsions stabilization

The aim of the present work was to study the feasibility of fabricating poly (lactic acid) (PLA) microspheres stabilized Pickering emulsions. For this purpose, the PLA microspheres were first prepared by oil-water emulsion solvent evaporation method. The effects of preparation conditions such as hydrophilic-lipophilic balance (HLB) value, emulsifier concentration, oil-water ratio and preparation temperature were evaluated by using optical microscopy. Besides, orthogonal experiments were designed to investigate the influence of preparation parameters on average diameter and uniformity, include stirring time, stirring speed, and PLA and polyvinyl alcohol (PVA) concentrations. Based on the analysis of orthogonal experimental results, an optimal level of parameters was defined for the fabrication of PLA microspheres. Furthermore, these microspheres were applied to the stabilization of Pickering emulsions, and the optimal Pickering emulsion with uniform microstructure was obtained through the adjustment of PLA microspheres concentrations. This study opens up a promising way for producing PLA microspheres stabilized Pickering emulsions.

Antibacterial and antibiofilm activity of phenyllactic acid against Enterobacter cloacae

Previous studies revealed that 3-Phenyllactic acid (PLA) was an antimicrobial compound with broad-spectrum activity. In this study, the efficacy of PLA to inactivate Enterobacter cloacae planktonic cells, biofilms, and its antibacterial mechanism were evaluated. Results indicated that 1% PLA reduced E. cloacae populations by about 6 log CFU/ml for planktonic cells and by 2.83 log CFU/ml for biofilm cells after 10-min treatments. TEM images revealed the damaged cell structure and leakage of the intracellular components. The permeability of the cytoplasmic membrane of E. cloacae was increased when the treated PLA concentrations was raised. Flow cytometry analysis further revealed that almost all the bacterial cells were damaged after treatment with 1% PLA for 30 min. The damages on bacterial cell membrane in the biofilms caused by 1% PLA treatment were also observed by confocal laser scanning microscopy analysis. These findings revealed that PLA was effective in inactivating planktonic and biofilm (or biofilm-associated) E. cloacae cells mainly by the mechanisms of cell membrane damage and leakage of the intracellular components.

Effects of phenyllactic acid as sanitizing agent for inactivation of Listeria monocytogenes biofilms

3-Phenyllactic acid (PLA) has been reported as an antimicrobial compound with broad-spectrum activity, and it can be produced by food-grade microorganisms, including a wide range of lactic acid bacteria species. In this study, the efficacy of PLA to inactivate Listeria monocytogenes planktonic cells and biofilms was determined and compared with the killing effects of lactic acid (LA), and levulinic acid (LVA) with sodium dodecyl sulfate (SDS). L. monocytogenes biofilms of different maturities, i.e., 37 °C for 3 and 7 d and 15 °C for 4 and 7 d, were produced on 24-well flat-bottom polystyrene plates and treated with PLA (0.25%–3%), LA (1% and 3%), and 3% LVA plus 2% SDS for 5, 10, 30, 60 min, respectively. The results of pure culture assays revealed that 1% PLA reduced the population of L. monocytogenes by 7 log CFU/ml within 1 min. The biofilms assays revealed that L. monocytogenes biofilms could be inactivated to different degrees by the sanitizer treatments. The killing effect of PLA treatment was increased as exposure time and PLA concentrations were increased. The sanitizers of 3% PLA and 1% PLA effectively inactivated the early mature biofilm after a 5-min treatment, whereas 3% PLA was better than all the other sanitizers, including 1% PLA, 3% LA, 3% LVA and 2% SDS for inactivation of the late mature biofilm after a 5-min treatment. Confocal laser scanning microscopy analysis revealed that bacterial cell damages in the biofilm were enhanced as the PLA concentrations and exposure times were increased. These results suggested that PLA was effective in inactivating L. monocytogenes and its biofilm, even for the late mature biofilm.

Reactive modification and compatibilization of poly(lactide) and poly(butylene adipate‐co‐terephthalate) blends with epoxy functionalized‐poly(lactide) for blown film applications

ABSTRACTBiodegradable blown films comprising of poly(lactide) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) were produced using epoxy functionalized‐poly(lactide) (EF‐PLA) reactive modifiers for rheological enhancement and compatibilization. The epoxy groups on the EF‐PLA modifiers react with PBAT forming an in situ copolymer that localizes at the blend interphase resulting in compatibilization of the polymer blend components. The EF‐PLA modified polymer blends have improved melt strength and the resultant films showed better processability as seen by increased bubbled stability. This allowed for blown films with higher PLA content (70%) compared to the unmodified control films (40%). The static charge build‐up typically experienced with PLA film blowing was decreased with the inclusion of EF‐PLA yielding films with better slip and softness. The compatibilization effect of the EF‐PLA modifiers resulted in significant improvement in mechanical properties. For example, dart test performance was up to four times higher than the control, especially at higher PLA concentrations. Therefore, the rheological enhancement and compatibilization effects of the EF‐PLA reactive modifiers make them ideally suited to create high PLA content films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 43310.

Conductive 3D microstructures by direct 3D printing of polymer/carbon nanotube nanocomposites via liquid deposition modeling

In this work, a new three-dimensional (3D) printing system based on liquid deposition modeling (LDM) is developed for the fabrication of conductive 3D nanocomposite-based microstructures with arbitrary shapes. This technology consists in the additive multilayer deposition of polymeric nanocomposite liquid dispersions based on poly(lactic acid) (PLA) and multi-walled carbon nanotubes (MWCNTs) by means of a home-modified low-cost commercial benchtop 3D printer. Electrical and rheological measurements on the nanocomposite at increasing MWCNT and PLA concentrations are used to find the optimal processing conditions and the printability windows for these systems. In addition, examples of conductive 3D microstructures directly formed upon 3D printing of such PLA/MWCNT-based nanocomposite dispersions are presented. The results of our study open the way to the direct deposition of intrinsically conductive polymer-based 3D microstructures by means of a low-cost LDM 3D printing technique.

Electrospun composite poly(lactic acid)/polyaniline nanofibers from low concentrations in CHCl3: Making a biocompatible polyester electro-active

Nanofibers of poly(lactic acid) (PLA) blended with polyaniline (PANi) were fabricated via electrospinning at much lower PLA concentrations (∼1wt%) in CHCl3 than reported before using a more efficient technique of preparing the solutions. The polymer nanofibers had diameters in the range 10 nm–300 nm. Nanofibers prepared with a 3 wt% PLA/PANi solution were conducting and were used to fabricate a diode which was electrically characterized and exhibited a low turn-on voltage and a rectification ratio of 500. The device characteristics were analyzed using the standard thermionic emission model of a Schottky junction and yielded an ideality factor of 1.6 and a barrier height of 0.49 eV. Using a simple circuit, the diode was able to rectify a low frequency alternating current signal with an efficiency of 10%. The ability to engineer insulating PLA into nanofibers that are electro-active extends the range of applications of this biocompatible and biodegradable polyester to include electronic devices that have reduced toxicity.

Biosurfactant stabilized anticancer biomolecule-loaded poly (d,l-lactide) nanoparticles

PLA nanoparticles (NPs) were prepared via green route using turmeric (Curcuma longa) extract (TE) as biostabiliser/biosurfactant. Of the 29 formulations, two formulations of TE synthesized PLA NPs were evaluated for encapsulation and controlled release of well known antioxidant and less bioavailable molecules curcumin and quercetin. Size of curcumin loaded PLA NPs synthesized using 0.8mg/ml PLA (C-En-D) and 0.1mg/ml PLA (C-En-P) were 203±77 and 110±44nm, respectively. However, quercetin loaded PLA NPs synthesized at 0.8mg/ml (Q-En-D) and 0.1mg/ml (Q-En-P) PLA concentrations were 170±95 and 102±31nm, respectively. The encapsulation efficiency of curcumin loaded PLA (C-En-D and C-En-P) NPs as well as quercetin loaded PLA (Q-En-D and Q-En-P) NPs was found ∼95%. In vitro release study of C-En-D, C-En-P, Q-En-D and Q-En-P NPs showed initial burst release followed by slow and sustained release. C-En-D NPs and Q-En-D NPs showing maximum in vitro release (∼100%) were evaluated for cytotoxicity. Blank PLA NPs, C-En-D and Q-En-D NPs were found to be safe against normal human leukocytes up to 2mg/ml dose. Both C-En-D and Q-En-D NPs showed anticancer activity against A549 cell line. But Q-En-D NPs showed better anticancer activity than C-En-D NPS on A549 cells. While blank PLA NPs did not possess anticancer activity. TE extract stabilized PLA NPs were non-toxic, biocompatible and safe to normal human leukocytes. Such technology will be better, effective and safer in use for anticancer as well as other biological application.

Water Resistance and Barrier Properties Improvement of Paperboard by Poly(Lactic Acid) Electrospraying

This research attempted to improve water resistance and barrier properties of paperboard by electrospraying the material with poly(lactic acid) (PLA). The focus was to reduce the amount of PLA in the coating process and to achieve the thinnest possible PLA coating layer. PLA solutions were prepared at 0.5%, 1%, 2%, 3% and 4% (w/v) in chloroform. PLA solution (10 ml) was sprayed onto the paperboard. The results showed that water and oil contact angles of paperboard were significantly increased after electrospraying. Water and oil absorption was significantly reduced, especially when using PLA concentration of 1%. PLA concentrations below 1% produced too few PLA particles on the surface for full coverage, whereas concentrations above 1% led to an uneven agglomeration of PLA particles on the substrate. The results also showed that water vapour transmission rate and oxygen transmission rate of paperboard were significantly reduced at PLA concentration of at least 1%. On the basis of electrospraying technique, the amount of PLA can be significantly reduced to achieve results comparable to other common coating methods. Copyright © 2013 John Wiley & Sons, Ltd.