Lactic Acid Polymer Research Articles

Mechanical finite element analysis of needle tip shape to develop insertable polymer-based microneedle without plastic deformation.

Mechanical finite element analysis of needle tip shape to develop insertable polymer-based microneedle without plastic deformation.

Antibacterial properties of bimetallic nanopattern induced by excimer laser on PTFE nanotextile.

Antibacterial properties of bimetallic nanopattern induced by excimer laser on PTFE nanotextile.

Zero Waste Concept in Production of PLA Biocomposites Reinforced with Fibers Derived from Wild Plant (Spartium junceum L.) and Energy Crop (Sida hermaphrodita (L.) Rusby).

This research follows the principles of circular economy through the zero waste concept and cascade approach performed in two steps. Our paper focuses on the first step and explores the characteristics of developed biocomposite materials made from a biodegradable poly(lactic acid) polymer (PLA) reinforced with natural fibers isolated from the second generation of biomass (agricultural biomass and weeds). Two plants, Spartium junceum L. (SJL) and Sida hermaphrodita (SH), were applied. To enhance their mechanical, thermal, and antimicrobial properties, their modification was performed with environmentally friendly additives-linseed oil (LO), organo-modified montmorillonite nanoclay (MMT), milled cork (MC), and zinc oxide (ZnO). The results revealed that SH fibers exhibited 38.92% higher tensile strength than SJL fibers. Composites reinforced with SH fibers modified only with LO displayed a 27.33% increase in tensile strength compared to neat PLA. The addition of LO improved the thermal stability of both biocomposites by approximately 5-7 °C. Furthermore, the inclusion of MMT filler significantly reduced the flammability, lowering the heat release rate to 30.25%, and enabling the categorization of developed biocomposite in a group of flame retardants. In the second step, all waste streams generated during the fibers extraction process are repurposed into the production of solid biofuels (pellets, briquettes) or biogas (bio)methane.

PLGA Polymers and Doxorubicin for the Treatment of Malignant Gliomas in Adults: An Overview

Malignant brain tumors, such as glioblastoma and astrocytoma, are the most aggressive diffuse gliomas with a high grade (4) of malignancy in adults, leading to high mortality. The development of pharmacological approaches to drug delivery systems has led to increased effectiveness and reduced systemic toxicity of anticancer therapy. Delivery systems, such as implants, plates, gels, and micro- and nanoparticles, are used as carriers for anticancer substances, improving their solubility and biodistribution. These delivery systems affect the mechanism of drug action, reduce toxicity, Micro- and nanoparticles can penetrate physiological barriers of the body, including the blood-brain barrier (BBB). Due to changes in the microvascular system, they linger and accumulate in the area of pathology. Despite extensive data on delivery systems, only a few have undergone clinical trials and been adopted into clinical practice. For over 20 years, polymeric plates containing carmustine have been clinically used to treat malignant brain tumors. The search for safer and more effective forms of drug anti-tumor agents continues, as glioblastoma remains an incurable disease. Doxorubicin is a primary chemotherapy agent with proven efficacy, which is included in standard therapy for almost all tumor types. However, it is not used to treat central nervous system tumors, as it is believed that it does not cross the BBB. The polymers of lactic acid and glycolic acid (PLGA or PLG) are biocompatible and biodegradable. Standards for different tumor types where doxorubicin is used. We describe the mechanisms of action of polymeric and nanoparticle forms of chemotherapy drugs, the prospects of using PLGA polymers, and assess possible ways to deliver doxorubicin and other medications for brain tumors effectively.

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

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

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

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

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

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

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

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

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

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

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

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