Lactic Acid Polymer Research Articles

A review of exploring the synthesis, properties, and diverse applications of poly lactic acid with a focus on food packaging application.

Polylactic acid (PLA) is an aliphatic polyester, which is primarily synthesized from renewable resources through the polycondensation or ring-opening polymerization of lactic acid (LA)/lactide. LA can be conveniently produced via the fermentation of sugars obtained from renewable sources such as corn and sugar cane. Due to its biodegradable and biocompatible nature, PLA exhibits a vast range of applications. Its advantages include non-toxicity, environmental safety, and compatibility with human biological systems. PLA finds significant use in various biomedical applications, including implants, tissue engineering, sutures, and drug delivery systems. Additionally, PLA serves as a renewable and biodegradable polymer of extensive utility in film production, offering an alternative to petrochemical-based polymers. Moreover, the properties of PLA-based films can be tailored by incorporating extracts, polysaccharides, proteins, and nano-particles. This review encompasses LA production, PLA synthesis, and diverse applications of PLA and further explores the potential of PLA in the realm of packaging.

Preparation and Characterization of Poly(lactic acid)-Based Poly(ethylene glycol) and Daphne Essential Oil-Loaded Smart Nanofibers for Thermal Protection.

Phase change material (PCM) stores latent heat energy, and poly(ethylene glycol) (Mw: 4000) (PEG 4000) is also a solid-liquid PCM. PEG and poly(lactic acid) (PLA) polymers are biodegradable. Essential oils are known as plant extracts with antimicrobial properties. In this study, daphne essential oil (DEO) obtained by the distillation method and PLA/PEG/DEO composite nanofibers were prepared by the electrospinning method with PLA, PEG 4000, and daphne (Laurus nobilis L.) essential oil in certain ratios (100/100/20, 100/120/20, and 100/150/20). DEO showed an antibacterial effect against Staphylococcus aureus and Escherichia coli bacteria. Thermal behaviors of the nanofibers were characterized by differential scanning calorimetry and thermogravimetric analysis. Morphological features were observed by scanning electronic microscopy (SEM), crystal behavior by X-ray diffraction analysis, and molecular structures were examined by Fourier transform infrared spectroscopy. Essential oil composition was determined by GC-MS. The thermal decomposition temperatures of the nanofibers were found between 250 and 276 °C, and the latent heat storage energies of nanofibers were 69.06, 86.76, and 96.39 J g-1 at temperatures 59.0 and 54.37 °C. High PCM added fiber was observed as 182 nm diameter with 3.264 μm diameter spheres. The produced nanofiber matrix has the potential to be used in applications such as medicine, textile, and hot food logistics.

Preparation and Characterization of Novel Poly(Lactic Acid) Composites Reinforced with “Latxa” Sheep Wool Fibers: The Effect of Peroxide Surface Treatments and Fiber Content

“Latxa” sheep wool is rough, and it is not used in the textile industry because the fiber diameter is high compared with other wool fibers. Nowadays, this wool is considered as disposal and, with the aim to give it value, new uses must be explored. In the current work, the “Latxa” sheep wool fiber was evaluated as poly(lactic acid) (PLA) polymer reinforcement. With the objective to optimize fiber/matrix adhesion, fibers were surface modified with peroxide. Oxidation treatment with peroxide led to chemical modifications of the wool fibers that improved the fiber/PLA adhesion, but the strength values achieved for the composites were lower compared to the neat PLA ones. The mechanical properties obtained in the current work were compared with the literature data of the PLA composites reinforced with vegetable fibers. The wool fibers showed inferior mechanical properties compared to the vegetable fiber counterparts. However, the preliminary results indicated that the incorporation of wool fibers to PLA reduced the flammability of composites.

Fabrication and characterization of poly(methyl vinyl ether maleic anhydride) blended poly(lactic acid) ultrafiltration membrane with upgraded antifouling and separation performance

In this present study, a novel environment-friendly bio-polymeric hybrid ultrafiltration membrane was fabricated by incorporating poly(methyl vinyl ether maleic anhydride) (PMVEAMA) into the poly(lactic acid) (PLA) polymer matrix. The integration of PMVEAMA into PLA significantly altered the membrane's structural morphology, functional characteristics, and filtration performance. As a result, key functional parameters like membrane porosity and water content were increased, which exhibiting the improved hydrophilicity. Furthermore, the molecular weight cut-off of the PLA/PMVEAMA membrane reached up to a maximum of 66.5 KDa with an average pore size of 9.14 nm, subsequently improving the flux of the membrane up to 2.8 times than PLA membrane. The functional capacity of the synthesized membrane was further assessed by testing its ability to filter toxic chlorophenolic compounds. Rejection studies reveal that the PLA/PMVEAMA membrane achieved a rejection efficiency of 44.64 % pentachlorophenol (PCP) and 51.85 % 2,4-dichlorophenol (DCP). Moreover, fouling studies revealed enhanced PCP and DCP flux recovery ratios of 50.94 % and 51.40 %, respectively, with a significant reduction in the flux decline rate. Additionally, the synthesized PLA/PMVEAMA membranes improved stability and regenerative properties up to 12 filtration cycles and antifouling properties highlight its potential to filter chlorophenolic compounds from wastewater.

Determination of the true density and the filler content of pinus sylvestris wood particles in polymer‐wood‐composites

AbstractMeasuring the natural fiber content in fiber‐filled polymers remains challenging. Conventional methods, such as density calculations based on the specific bulk densities of the mixed components or determining the remaining fiber weights after calcination, often yield inaccurate results. Even helium pycnometer measurements tend to overestimate the true density of natural fibers. This study introduces a novel and potentially more cost‐effective method to accurately determine the true density of natural filler materials. The approach involves mixing these fillers into plastic melts and injection molding them under pressures up to 1000 bar. Using this method, the true density of Pinus sylvestris heartwood chips combined with a lactic acid polymer was precisely calculated as 1.40092 g/cm3 ± 0.0102 g/cm3. Knowing the true density of material like Pinus sylvestris heartwood offers an accurate calculation of filler content in unknown recycled mixtures. This method can calculate the amount of wood fillers in polymer compounds, such as those from former decking, fences, privacy screens or soundproof wall claddings.Highlights Precise method to determine specific actual densities of biofillers High‐resolution CT measurements of polymers filled with wood fibers Localization of density fluctuations in wood fiber filled polylactide Methodology for measuring the biofiber content of recyclates

Determination of 3-(4-hydroxyphenyl)lactic acid by an amperometric sensor with molecularly imprinted polymers

Sepsis is a life-threatening organ dysfunction caused by the dysregulation of the body’s response to infection. If sepsis is not diagnosed early and treated, it can lead to septic shock, multi-organ failure, and death. The diagnosis of sepsis, traditionally relying on clinical findings and detection of aetiologically significant microorganisms in the blood and foci, has been improved in recent years by the search for and implementation of various biomarkers. One promising biomarker of sepsis is 3-(4-hydroxyphenyl)lactic acid (HPLA). In this study, we developed an amperometric sensor modified with a molecularly imprint polymer (MIP) of hydroxyphenyl lactic acid and proved the fundamental possibility of determining HPLA by this sensor in model aqueous solutions. Molecularly imprinted polymers are widely used to separate substances and to produce selective sensors. Among the variety of selective materials, polyimides are of particular interest. Therefore, in this study, we developed MIP sensors imprinted with 4-hydroxyphenyl lactic acid on the basis of copolymer of 1,2,4,5-benzoltetracarboxylic acid with 4,4'-diaminodiphenyloxide. The sensors were prepared in two stages (1st stage at 80°С, 2nd stage at 180°С) by non-covalent imprinting method. High selectivity of PMO-sensors towards target molecules was confirmed. The range of the determined concentrations of the acid was 0.2-0.0002 mg/dm3. The experimentally determined detection limit of 4-hydroxyphenyl lactic acid was 4.5·10-5 mg/dm3.

The effect of spent coffee ground (SCG) loading, matrix ratio and biological treatment of SCG on poly(hydroxybutyrate) (PHB)/poly(lactic acid) (PLA) polymer blend

This study investigates the effects of SCG embedded into biodegradable polymer blends and aimed to formulate and characterise biomass-reinforced biocomposites using spent coffee ground (SCG) as reinforcement in PHB/PLA polymer blend. The effect of SCG filler loading and varying PHB/PLA ratios on the tensile properties and morphological characteristics of the biocomposites were examined. The results indicated that tensile properties reduction could be due to its incompatibility with the PHB/PLA matrixSCG aggregation at 40 wt% content resulted in higher void formation compared to lower content at 10 wt%. A PHB/PLA ratio of 50/50 with SCG loading 20 wt% was chosen for biocomposites with treated SCG. Biological treatment of SCG using Phanerochaete chrysosporium CK01 and Aspergillus niger DWA8 indicated P. chrysosporium CK01 necessitated a higher moisture content for optimum growth and enzyme production, whereas the optimal conditions for enzyme production (50–55 %, w/w) differed from those promoting A. niger DWA8 growth (40 %, w/w). SEM micrographs highlighted uniform distribution and effective wetting of treated SCG, resulting in improvements of tensile strength and modulus of biocomposites, respectively. The study demonstrated the effectiveness of sustainable fungal treatment in enhancing the interfacial adhesion between treated SCG and the PHB/PLA matrix.

Novel 3D-Printed lead-free radiation protection apron in the medical X-ray and thermal neutron energy range

In this study, we employed 3D printing technology to fabricate poly lactic acid (PLA) polymer samples infused with gadolinium oxide nanoparticles at additive rates of 10% and 20%. The objective was to explore their potential as radiation shielding aprons within the medical X-ray and thermal neutron energy spectrum. To facilitate comparisons, a PLA polymer sample with no additive was also produced. The homogeneity and well-defined structures of the PLA samples were observed using SEM and EDS analyses. Additionally, the excellent thermal stability of the proposed test samples was reported. In terms of gamma-ray shielding, there is a remarkable consistency between experiment, theory and simulation outcomes with a maximum discrepancy of approximately 5%. P-PLA-Gd20 sample exhibits attenuation capabilities against X-rays to a level that could serve as an alternative to lead. Additionally, the thermal and fast neutron attenuation effectiveness of the prepared samples were determined. A shielding effectiveness of 100% against thermal neutrons was achieved using a 10 mm sample thickness and the P-PLA-Gd20 sample. The findings consistently highlight the efficacy of the proposed polymer sample with a 20% gadolinium oxide nanoparticle additive, positioning it as a viable and promising alternative to traditional lead aprons.

Miniaturized screening and performance prediction of tailored subcutaneous extended-release formulations for preclinical in vivo studies

Microencapsulation of active pharmaceutical ingredients (APIs) for preparation of long acting injectable (LAI) formulations is an auspicious technique to enable preclinical characterization of a broad variety of APIs, ideally independent of their physicochemical and pharmacokinetic (PK) characteristics. During early API discovery, tunable LAI formulations may enable pharmacological proof-of-concept for the given variety of candidates by tailoring the level of plasma exposure over the duration of various timespans. Although numerous reports on small scale preparation methods for LAIs utilizing copolymers of lactic and glycolic acid (PLGA) and polymers of lactic acid (PLA) highlight their potential, application in formulation screening and use in preclinical in vivo studies is yet very limited. Transfer from downscale formulation preparation to in vivo experiments is hampered in early preclinical API screening by the large number of API candidates with simultaneously very limited available amount in the lower sub-gram scale, lack of formulation stability and deficient tunability of sustained release.We hereby present a novel comprehensive platform tool for tailored extended-release formulations, aiming to support a variety of preclinical in vivo experiments with ranging required plasma exposure levels and timespans. A novel small-scale spray drying process was successfully implemented by using an air brush based instrument for preparation of PLGA and PLA based formulations. Using Design of Experiments (DoE), required API amount of 250 mg was demonstrated to suffice for identification of dominant polymer characteristics with largest impact on sustained release capability for an individual API. BI-3231, a hydrophilic and weakly acidic small compound with good water solubility and permeability, but low metabolic stability, was used as an exemplary model for one of the many candidates during API discovery. Furthermore, an in vitro to in vivo correlation (IVIVC) of API release rate was established in mice, which enabled the prediction of in vivo plasma concentration plateaus after single subcutaneous injection, using only in vitro dissolution profiles of screened formulations.By tailoring LAI formulations and their doses for acute and sub-chronic preclinical experiments, we exemplary demonstrate the practical use for BI-3231. Pharmacological proof-of-concept could be enabled whilst circumventing the need of multiple administration as result of extensive hepatic metabolism and simultaneously superseding numerous in vivo experiments for formulation tailoring.

Production and Characterization of Bioactive and Antimicrobial Titanium Oxide Surfaces with Silver Nanoparticles and a Poly(lactic Acid) Microfiber Coating

Silver nanoparticles (AgNp) were deposited on highly porous TiO2 surfaces by the dripping of a colloidal AgNp solution to provide antimicrobial activity. Micro-porous TiO2 surfaces were obtained on commercially pure titanium by micro-arc oxidation in an electrolyte containing Ca and P precursors. In addition, as silver can be toxic to cells, these surfaces were uniformly covered with the biocompatible and bioresorbable poly(lactic acid) (PLA) polymer by electrospinning, aiming at promoting a controlled release of silver ions to the medium. The resulting AgNp-containing surfaces were characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD), and in vitro assays were performed to evaluate their antimicrobial activity and bioactivity. Tests revealed that the surfaces showed antimicrobial activity against Staphylococcus aureus, with better results for the surfaces without PLA. However, all the surfaces presented good biocompatibility in assays with mouse MC3T3-E1 pre-osteoblasts, and greater cell differentiation for the polymer-coated surfaces. Finally, the PLA ultrafine fibers electrospun on the TiO2/AgNp surfaces allowed a controlled release of silver ions in the phosphate-buffered saline (PBS) medium.

Experimental investigation and statistical analysis of tensile strength and thermal conductivity of polylactic acid nanocomposites

Nowadays, biodegradable polymers have gained more attention due to environmental concerns and several inherent properties. However, poor mechanical and thermal properties limit their use for various applications. The nanocomposite is one of the techniques to improve its mechanical and thermal properties. Hence, this technique may be employed to improve its desired properties. This work reports the synthesis and characterization of biodegradable polylactic acid (PLA) nanocomposites. PLA was synthesized by the ring-opening polymerization of lactic acid, magnesium phosphate (MgP), and calcium phosphate (CaP) nanoparticles were added into the PLA matrix. The nanocomposites were prepared by ultrasonic vibration-assisted melt mixing and vacuum casting techniques. The prepared PLA nanocomposites were further characterized to determine their tensile strength and thermal conductivity. The experiments were designed by employing the central composites design to study the effect of MgP and CaP nanoparticle concentration on the mechanical and thermal properties of PLA nanocomposites. The result indicates that the highest tensile strength was achieved for 10 wt% CaP and 2.35 wt% concentration whereas maximum thermal conductivity of PLA nanocomposites was obtained for 20 wt% CaP and 2.35 wt% concentration.

Production of poly(3-hydroxybutyrate)/poly(lactic acid) from industrial wastewater by wild-type Cupriavidus necator H16

The massive production of urban and industrial wastes has created a clear need for alternative waste management processes. One of the more promising strategies is to use waste as raw material for the production of biopolymers such as polyhydroxyalkanoates (PHAs). In this work, a lactate-enriched stream obtained by anaerobic digestion (AD) of wastewater (WW) from a candy production plant was used as a feedstock for PHA production in wild-type Cupriavidus necator H16. Unexpectedly, we observed the accumulation of poly(3-hydroxybutyrate)/poly(lactic acid) (P(3HB)/PLA), suggesting that the non-engineered strain already possesses the metabolic potential to produce these polymers of interest. The systematic study of factors, such as incubation time, nitrogen and lactate concentration, influencing the synthesis of P(3HB)/PLA allowed the production of a panel of polymers in a resting cell system with tailored lactic acid (LA) content according to the GC–MS of the biomass. Further biomass extraction suggested the presence of methanol soluble low molecular weight molecules containing LA, while 1 % LA could be detected in the purified polymer fraction. These results suggested that the cells are producing a blend of polymers. A proteomic analysis of C. necator resting cells under P(3HB)/PLA production conditions provides new insights into the latent pathways involved in this process. This study is a proof of concept demonstrating that LA can polymerize in a non-modified organism and paves the way for new metabolic engineering approaches for lactic acid polymer production in the model bacterium C. necator H16.

Enhancing Structural and Thermal Properties of Poly(lactic acid) Using Graphene Oxide Filler and Anionic Surfactant Treatment.

Graphene has attracted extensive attention in various fields due to its intriguing properties. In this work, nanocomposite films based on poly(lactic acid) (PLA and PLLA) polymers filled with graphene oxide (GO) were developed. The impact of treating GO with the anionic surfactant dioctyl sulfosuccinate sodium salt (AOT) on the properties of the resulting nanocomposites was investigated. To determine the morphological, optical, and structural properties of the obtained materials, physicochemical analyses were performed, including scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis. Additionally, the thermal properties and wettability of neat polymers and nanocomposites were thoroughly investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and contact angle analysis. It was observed that GO was well dispersed throughout the PLA and PLLA matrix, leading to stronger interface bonding. The results demonstrate that the untreated and treated GO improved the crystallinity and thermal stability properties of the PLA and PLLA. However, the AOT-treated GO has significantly higher performance compared to the untreated GO in terms of crystallinity, melting temperature (increased by ~15 °C), and wettability (the contact angle decreased by ~30°). These findings reveal the high performance of the developed novel composite, which could be applied in tissue engineering as a scaffold.

Microbial synthesis of eco-friendly polylactate plastic from low-cost agro-industrial wastes as an alternative to petrochemical-based plastic

<p>Bioplastics made from renewable resources, such as contemporary biomass, have been developed more quickly as a result of global pollution from plastics made from petroleum, but it is still unclear how these materials will affect ecosystems. A common biopolymer that will make up 33% of the bioplastics produced in 2021 is polylactic acid (PLA). Forty-two bacterial isolates (soil, food wastes, and water wastes) were obtained, and 8 lactic acid bacteria were used for lactic acid (LA) production. These bacteria were classified into three categories, namely high, moderate and low LA producing bacteria which gave LA concentrations ranged from >1.0 g/L (3 bacteria), 0.5 to 1.0 g/L (21 bacteria) and 0.1 to 0.5 g/L (26 bacteria), respectively. The Sudan black staining method revealed that 16 bacteria out of 50 were capable of storing PLA granules, with three lactic acid bacteria referred to as Lactococcus thermophilus, Lactobacillus rhamenose, and Lactobacillus retrieria being the most efficient. The sodium dodecyl sulphate procedure was used to extract PLA from the selected LAB, and the results revealed that L. rhamnose was the most effective strain for producing both lactic acid and PLA. The most important fermentation parameters for lactic acid and polylactate polymer production were evaluated using an optimal custom (factorial) design. The interaction between three factors of selected potato oil waste, C/N ratio (48/1), and inoculum size (10%) resulted in an increase in lactic acid and polylactate polymer productivity by L. rhamenose L6, which reached 0.85 g/L, 0.96 g/L, and cell dry weight 2.33g/L, respectively.</p>

Applications of poly(lactic acid) in bone tissue engineering: A review article.

Bone tissue engineering is a promising approach to large-scale bone regeneration. This involves the use of an artificial extracellular matrix or scaffold and osteoblasts to promote osteogenesis and ossification at defect sites. Scaffolds are constructed using biomaterials that typically have properties similar to those of natural bone. In this study, which is a review of the literature, various evidences have been discussed in the field of Poly Lactic acid (PLA) polymer application and modifications made on it in order to induce osteogenesis and repair bone lesions. PLA is a synthetic aliphatic polymer that has been extensively used for scaffold construction in bone tissue engineering owing to its good processability, biocompatibility, and flexibility in design. However, PLA has some drawbacks, including low osteoconductivity, low cellular adhesion, and the possibility of inflammatory reactions owing to acidic discharge in a living environment. To overcome these issues, a combination of PLA and other biomaterials has been introduced. This short review discusses PLA's characteristics of PLA, its applications in bone regeneration, and its combination with other biomaterials.

Influence of Weathering on the Degradation of Cellulose Acetate Microplastics Obtained from Used Cigarette Butts.

Cellulose acetate is used in many applications, including for cigarette filters. Unfortunately, unlike cellulose, its (bio)degradability is under question, yet it often ends up uncontrolled in the natural environment. The main purpose of this study is to compare the effects of weathering on two types of cigarette filter (classic filters and newer filters that have more recently arrived on the market) following their use and disposal in nature. Microplastics were prepared from polymer parts of used (classic and heated tobacco products-HTP) cigarettes and artificially aged. TG/DTA, FTIR, and SEM analyses were performed both before and after the aging process. Newer tobacco products contain an additional film made of a poly(lactic acid) polymer which, like cellulose acetate, burdens the environment and poses a risk to the ecosystem. Numerous studies have been conducted on the disposal and recycling of cigarette butts and cigarette butt extracts, revealing alarming data that have also influenced the decisions of the EU, who addressed the disposal of tobacco products in the EU Directive (EU) 2019/904. Despite this, there is still no systematic analysis in the literature evaluating the impact of weathering (i.e., accelerated aging) on the degradation of cellulose acetate in classic cigarettes compared with that in newer tobacco products that have recently appeared on the market. This is of particular interest given that the latter have been promoted as being healthier and environmentally friendly. The results show that in cellulose acetate cigarette filters the particle size decreased after accelerated aging. Also, the thermal analysis revealed differences in the behavior of the aged samples, while the FTIR spectra showed no shifts in the position of the peaks. Organic substances break down under UV light, which can be seen by measuring the color change. The PLA film was found to be more stable than cellulose acetate under the influence of UV light.

Effects of Wet and Dry Treatments on Surface Functional Groups and Mechanical Properties of Flax Fiber Composites

Flax fibers have found widespread use in eco-composite materials because of their remarkable mechanical properties compared to glass fibers. However, their low stability limits their use on a larger scale when employed in hot or humid environments. Therefore, the surfaces should be modified before the composite process to provide the best interfacial interactions and increase the dispersion of natural fibers. To tackle this problem, two kinds of modifications can be considered: wet and dry modifications. This research explores different methods to improve the adhesion between flax fibers and the poly lactic acid (PLA) polymer. Morphological and chemical modifications in the presence of acetone, alkali (as a wet modification), and with air atmospheric pressure plasma (as a dry modification) are compared in this research. The results revealed that altering the chemical characteristics on the surface significantly changed the mechanical properties of the final composite. More specifically, the Fourier transform infrared spectroscopy (FTIR) data indicate that wax-related peaks (2850 and 2920 cm−1) were eliminated by both wet and dry treatments. Dynamic mechanical analysis (DMA) results also highlighted that a better bond between the flax fibers and the PLA matrix is obtained with the plasma modification.

Efficient sonodynamic ablation of deep-seated tumors via cancer-cell-membrane camouflaged biocompatible nanosonosensitizers

Ultrasound (US)-triggered therapies are promising in cancer treatments, and their effectiveness can be enhanced through the proper camouflage of sonosensitizers. Herein, we have constructed cancer cell membrane (CCM)-camouflaged sonosensitizers for homotypic tumor-targeted sonodynamic therapy (SDT). The camouflaged sonosensitizers have been prepared by encapsulating hemoporfin molecules in poly(lactic acid) polymers (H@PLA) and extruding with CCM from Colon Tumor 26 (CT26) cells, forming the H@PLA@CCM. Under excitation with US, the hemoporfin encapsulated in H@PLA@CCM can convert O2 into cytotoxic 1O2, which exerts an efficient sonodynamic effect. The H@PLA@CCM nanoparticles show enhanced cellular internalization to CT26 cells compared to H@PLA, and they also can be more efficiently engulfed by CT26 cells than by mouse breast cancer cells, due to the homologous targeting ability of CT26 CCM. After the intravenous injection, the blood circulation half-life of H@PLA@CCM is determined to be 3.23 h which is 4.3-time that of H@PLA. With high biosafety, homogeneous targeting ability, and sonodynamic effect, the combination of H@PLA@CCM and US irradiation has induced significant apoptosis and necrosis of tumor cells through the efficient SDT, achieving the strongest inhibition rate of tumors among other groups. This study provides insights into designing efficient and targeted cancer therapies using CCM-camouflaged sonosensitizers.

Properties of Poly (Lactic-co-Glycolic Acid) and Progress of Poly (Lactic-co-Glycolic Acid)-Based Biodegradable Materials in Biomedical Research.

In recent years, biodegradable polymers have gained the attention of many researchers for their promising applications, especially in drug delivery, due to their good biocompatibility and designable degradation time. Poly (lactic-co-glycolic acid) (PLGA) is a biodegradable functional polymer made from the polymerization of lactic acid (LA) and glycolic acid (GA) and is widely used in pharmaceuticals and medical engineering materials because of its biocompatibility, non-toxicity, and good plasticity. The aim of this review is to illustrate the progress of research on PLGA in biomedical applications, as well as its shortcomings, to provide some assistance for its future research development.

Antimicrobial Activity of Blow Spun PLA/Gelatin Nanofibers Containing Green Synthesized Silver Nanoparticles against Wound Infection-Causing Bacteria.

One of the main challenges in wound healing is the wound infection due to various causes, of which moisture is the most important reason. Owing to this fact, wound dressings that can collect wound moisture in addition to showing antibacterial properties have provided an important basis for wound healing research. In this study, gelatin and poly lactic acid (PLA) polymers were used in a wound dressing textile to provide gelation and structure strength properties, respectively. Meanwhile, silver nanoparticles (SNPs) synthesized through the green method were integrated into these fibers to provide the formed textile with antibacterial properties. Nanoparticles were made using donkey dung extract, and nanofibers were produced by the solution blow spinning method which has high production efficiency and low energy consumption among spinning methods. The produced nanoparticles were characterized and evaluated by UV-Vis, DLS, XRD, and FTIR methods, and the production of silver nanoparticles that were coated with metabolites in the extract was proven. In addition, the morphology and diameter of the resulted fibers and presence of nanoparticles were confirmed by the SEM method. The size and size distribution of the synthesized fibers were determined through analyzing SEM results. Gelatin nanofibers demonstrated a mean size of 743 nm before and 773 nm after nanoparticle coating. PLA nanofibers demonstrated a mean size of 57 nm before and 182 nm after nanoparticle coating. Finally, 335 nm was the mean diameter size of gelatin/PLA/SNPs nanofibers. Also, the textiles synthesized by PLA and gelatin which contained silver nanoparticles showed higher antibacterial activity against both gram-positive and gram-negative species compared to PLA and gelatin tissues without nanoparticles. Cytotoxicity test on L929 cells showed that silver nanoparticles incorporated textiles of PLA and gelatin show a very low level and non-significant toxicity compared to the free particles.