Porous Polylactic Acid Research Articles

Advanced superhydrophobic polylactic acid fibers with high porosity and biodegradability for efficient solvent recovery

The conventional oil-absorbing materials utilized for addressing oil and organic solvent pollution are plagued by the issue of secondary pollution. In this study, biodegradable porous polylactic acid (PLA) fiber materials were prepared using centrifugal spinning technology, with PLA and polyvinyl butyral (PVB) as raw materials. PVB was utilized as a pore-forming agent to fabricate multi-layered porous PLA fiber materials. When the content of PVB in the spinning solution was 14 %, the porous PLA fibers exhibited the maximum specific surface area of 60.7 m2/g and a porosity of up to 85.4 %, interior of the fiber contained numerous mesopores. Additionally, the porous PLA fibers demonstrated excellent superhydrophobic oil absorption properties, with a water static contact angle of 137.8° and oil or organic solvent absorption capacities ranging from 10 to 17.7 g/g. Furthermore, porous PLA fiber materials exhibited outstanding biodegradability, with a degradation mass loss rate of 42.3–45.1 %. Therefore, superhydrophobic and oleophilic biomass-based PLA fiber materials prepared in centrifugal spinning show promising applications in the recovery of organic solvents and oily substances.

Fabrication of micro-porous polymeric coating with dynamic drug-eluting property on plastic biliary stent for antiproliferative treatment

The current study aims to construct additional drug-eluting carrier for commercially available biliary stent, providing a practical strategy for the cost-efficient treatment of benign biliary stricture. Specifically, the commercially available biliary stent was endowed with porous polylactic acid coating via in-situ pore-formation induced by solvent treatment. The drug-eluting stent with fibroblast inhibition effect was successfully established by efficiently loading the antiproliferative drug of triamcinolone acetonide into the porous coating. The drug release behavior could be dynamically controlled by adjusting the pore morphology of the porous coating. The in-vitro coating degradation and the fibroblast inhibition effect of the drug-eluting stents were further evaluated to prove the effectiveness of the fabricated porous coating as an antiproliferative drug carrier.

Synthesis of bare and modified zerovalent iron nanoparticles and their use in porous polylactic acid composites for methyl orange removal

The main objective of this study was to assess the efficacy of two types of immobilised zerovalent iron nanoparticles (nZVI) incorporated into a porous biopolymer matrix of polylactic acid (PLA) as a novel multifunctional composite system for potential use in dye wastewater treatment. The study involved the preparation of unmodified and 2,6-pyridinedicarboxylic acid (PDCA) modified nZVI material using liquid phase reduction method. Zeta potential measurement and UV-Vis spectrophotometry revealed that the ligand-modified nZVI particles exhibited better dispersion stability in aqueous media than bare particles. SEM-EDS analysis showed a higher oxidation state of the ligand-modified nZVI particles and good dispersion and adhesion of nZVI particles in the mesoporous structure of PLA matrix. The removal efficiency of methyl orange was determined spectrophotometrically where a high efficiency (above 90 %) for high concentration of bare nZVI was detected. Its composites also showed an efficiency of 75 – 100 %. However, modified nZVI showed much lower efficiency, especially after embedding in the PLA matrix.

Preparation Method and Application of Porous Poly(lactic acid) Membranes: A Review.

Porous membrane technology has garnered significant attention in the fields of separation and biology due to its remarkable contributions to green chemistry and sustainable development. The porous membranes fabricated from polylactic acid (PLA) possess numerous advantages, including a low relative density, a high specific surface area, biodegradability, and excellent biocompatibility. As a result, they exhibit promising prospects for various applications, such as oil-water separation, tissue engineering, and drug release. This paper provides an overview of recent research advancements in the fabrication of PLA membranes using electrospinning, the breath-figure method, and the phase separation method. Firstly, the principles of each method are elucidated from the perspective of pore formation. The correlation between the relevant parameters and pore structure is discussed and summarized, subsequently followed by a comparative analysis of the advantages and limitations of each method. Subsequently, this article presents the diverse applications of porous PLA membranes in tissue engineering, oil-water separation, and other fields. The current challenges faced by these membranes, however, encompass inadequate mechanical strength, limited production efficiency, and the complexity of pore structure control. Suggestions for enhancement, as well as future prospects, are provided accordingly.

PLA tissue-engineered scaffolds loaded with sustained-release active substance chitosan nanoparticles: Modeling BSA-bFGF as the active substance

The utilization of basic fibroblast growth factor (bFGF) in the development of tissue-engineered scaffolds is both challenging and imperative. In our pursuit of creating a scaffold that aligns with the natural healing process, we initially fabricated chitosan-bFGF nanoparticles (CS-bFGF NPs) through electrostatic spraying. Subsequently, polylactic acid (PLA) fiber was prepared using electrospinning technique, and the CS-bFGF NPs were uniformly embedded within the pores of porous PLA fibers. Scanning electron micrographs illustrate the smooth surface of the nanoparticles, showing a porous structure intricately attached to PLA fibers. Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) analyses provided conclusive evidence that the CS-bFGF NPs were uniformly distributed throughout the porous PLA fibers, forming a robust physical bond through electrostatic adsorption. The resultant scaffolds exhibited commendable mechanical properties and hydrophilicity, facilitating a sustained-release for 72 h. Furthermore, the biocompatibility and degradation performance of the scaffolds were substantiated by monitoring conductivity and pH changes in pure water over different time intervals, complemented by scanning electron microscopy (SEM) observations. Cell experiments confirmed the cytocompatibility of the scaffolds. In animal studies, the group treated with 16 % NPs/Scaffold demonstrated the highest epidermal reconstruction rate. In summary, our developed materials present a promising candidate for serving as a tissue engineering scaffold, showcasing exceptional biocompatibility, sustained-release characteristics, and substantial potential for promoting epidermal regeneration.

Confined Water Dynamics in the Scaffolds of Polylactic Acid.

Resorbable polylactic acid (PLA) ultrathin fibers have been applied as scaffolds for tissue engineering applications due to their micro- and nanoporous structure that favor cell adhesion, besides inducing cell proliferation and upregulating gene expression related to tissue regeneration. Incorporation of multiwalled carbon nanotubes into PLA fibers has been reported to increase the mechanical properties of the scaffold, making them even more suitable for tissue engineering applications. Ideally, scaffolds should be degraded simultaneously with tissue growth. Hydration and swelling are factors related to scaffold degradation. Hydration would negatively impact the mechanical properties since PLA shows hydrolytic degradation. Water absorption critically affects the catalysis and allowance of the hydrolysis reactions. Moreover, either mass transport and chemical reactions are influenced by confined water, which is an unexplored subject for PLA micro- and nanoporous fibers. Here, we probe and investigate confined water onto highly porous PLA microfibers containing few amounts of incorporated carbon nanotubes by Fourier transform infrared (FTIR) spectroscopy. A hydrostatic pressure was applied to the fibers to enhance the intermolecular interactions between water molecules and C=O groups from polyester bonds, which were evaluated over the wavenumber between 1600 and 2000 cm-1. The analysis of temperature dependence of FTIR spectra indicated the presence of confined water which is characterized by a non-Arrhenius to Arrhenius crossover at T0 = 190 K for 1716 and 1817 cm-1 carbonyl bands of PLA. These bands are sensitive to a hydrogen bond network of confined water. The relevance of our finding relies on the challenge detecting confined water in hydrophobic cavities as in the PLA one. To the best of our knowledge, we present the first report referring the presence of confined water in a hydrophobic scaffold as PLA for tissue engineering. Our findings can provide new opportunities to understand the role of confined water in tissue engineering applications. For instance, we argue that PLA degradation may be affected the most by confined water. PLA degradation involves hydrolytic and enzymatic degradation reactions, which can both be sensitive to changes in water properties.

Interfacial-engineered robust and high performance flexible polylactic acid/polyaniline/MXene electrodes for high-perfarmance supercapacitors

Flexible supercapacitors with high mechanical strength, excellent flexibility, and high performance are highly desired to meet the increasing demands of flexible electronics. However, the trade-off between mechanical and electrochemical properties remains challenging. In this context, an interface-engineered strategy approach was proposed to construct polylactic acid (PLA)/polyaniline (PANI)/MXene (PPM) film electrodes for flexible supercapacitor applications. In the PPM electrode, the porous PLA prepared from the nonsolvent-induced-phase-separation method served as an ideal flexible substrate, providing excellent flexibility and high mechanical strength, whereas PANI as the coupling agent, enhanced the interfacial strength between PLA and the electroactive MXene that was firmly anchored and deposited on PLA through a facile layer-by-layer dip coating method. The tensile strength at break, elongation at break, and toughness of PPM are 53.09 MPa, 11.09 %, and 4.12 MJ/m3, respectively, much higher than those of pure MXene (29.36 MPa, 4.62 %, and 0.75 MJ/m3). At an optimum mass loading density of 3 mg cm−2 for MXene, the fabricated PPM3 film electrode achieved a high specific capacitance of 290.8 F g−1 at a current density of 1 A g−1 in the three-electrode setup, approximately 1.5 times that of 190.8 F g−1 for pure MXene. Meanwhile, the symmetric all-solid-state supercapacitor based on PPM3 film electrodes delivers a high specific capacitance of 193.7 F g−1 at a current density of 0.25 A g−1, with a corresponding high energy density of 9.3 Wh kg−1 at a power density of 291.3 W kg−1. The SC retains 86 % of its original capacitance even bent at 120° and also possesses an excellent fire-retardant ability, demonstrating its great potential for flexible and safe wearable electronics.

Microdroplets Encapsulated with NFATc1-siRNA and Exosomes-Derived from MSCs Onto 3D Porous PLA Scaffold for Regulating Osteoclastogenesis and Promoting Osteogenesis.

Osteoporotic-related fractures remains a significant public health concern, thus imposing substantial burdens on our society. Excessive activation of osteoclastic activity is one of the main contributing factors for osteoporosis-related fractures. While polylactic acid (PLA) is frequently employed as a biodegradable scaffold in tissue engineering, it lacks sufficient biological activity. Microdroplets (MDs) have been explored as an ultrasound-responsive drug delivery method, and mesenchymal stem cell (MSC)-derived exosomes have shown therapeutic effects in diverse preclinical investigations. Thus, this study aimed to develop a novel bioactive hybrid PLA scaffold by integrating MDs-NFATc1-silencing siRNA to target osteoclast formation and MSCs-exosomes (MSC-Exo) to influence osteogenic differentiation (MDs-NFATc1/PLA-Exo). Human bone marrow-derived mesenchymal stromal cells (hBMSCs) were used for exosome isolation. Transmission electron microscopy (TEM) and confocal laser scanning microscopy were used for exosome and MDs morphological characterization, respectively. The MDs-NFATc1/PLA-Exo scaffold was fabricated through poly(dopamine) and fibrin gel coating. Biocompatibility was assessed using RAW 264.7 macrophages and hBMSCs. Osteoclast formations were examined via TRAP staining. Osteogenic differentiation of hBMSCs and cytokine expression modulation were also investigated. MSC-Exo exhibited a cup-shaped structure and effective internalization into cells, while MDs displayed a spherical morphology with a well-defined core-shell structure. Following ultrasound stimulation, the internalization study demonstrated efficient delivery of bioactive MDs into recipient cells. Biocompatibility studies indicated no cytotoxicity of MDs-NFATc1/PLA-Exo scaffolds in RAW 264.7 macrophages and hBMSCs. Both MDs-NFATc1/PLA and MDs-NFATc1/PLA-Exo treatments significantly reduced osteoclast differentiation and formation. In addition, our results further indicated MDs-NFATc1/PLA-Exo scaffold significantly enhanced osteogenic differentiation of hBMSCs and modulated cytokine expression. These findings suggest that the bioactive MDs-NFATc1/PLA-Exo scaffold holds promise as an innovative structure for bone tissue regeneration. By specifically targeting osteoclast formation and promoting osteogenic differentiation, this hybrid scaffold may address key challenges in osteoporosis-related fractures.

(158) Comparison Implants for Penile Girth Enlargement: PPLA Shaft vs Silicone Implant

Abstract Introduction Male dissatisfaction with the penis size is the most common manifestation of penile dysmorphophobia. Despite the diversity of penis enlargement methods a single safe technique that fully satisfies patients has not yet been developed. Objective The aim of this work is to compare the results of a combined operation on installation of a silicone implant or a porous polylactic acid (PPLA) scaffold impregnated with autologous stem cells with simultaneous ligamenotaxis to increase the length and circumference of the penis. Methods In 2017–2023 there were performed penis enlargement surgeries in 3 centers. In Ukraine and Poland 38 patients from were operated with implantation of a porous Max Pol PLLA scaffold, and in Mexico implantation of silicone implants Peniflex in 36 patients was performed. The results of penis enlargement were evaluated in the early (2 months) and long-term (36 months) periods. Results While implanting a silicone implant the majority of the patients - 31 (86.1%) are satisfied with the result, 27 (75%) patients mention an improvement in sexual life, 31 (86.1%) also mention an increase in their own self-sufficiency. At the same time, some patients mentioned the following complications: 2 (5.6%) patients mentioned displacement of the silicone matrix, 1 (2.8%) patient mentioned prolapse of the implant, 1 (2.8%) patient mentioned a decrease in erection (which did not improve after removal of the implant), in 1 (2.8%) case the silicone implant had to be removed due to the fact that the patient did not liked the appearance. While using a collagen-like matrix made of polymerized polylactic acid impregnated with autological stem cells in 38 patients, we have seen one significant complication - prolapse that caused the removal of the matrix (in men that had denied circumcision before implantation). However, 5 (13.2%) patients required additional polylactic acid gel injections between 6 and 36 months to optimize the shape or volume of the penis. 34 (89.5%) patients mentioned an improvement in the sexual function and sexual sensations of their partner, harmonization of relationships in a couple, and 36 (97.4%) men - an increase in a sense of self-sufficiency. In 3 years most of the patients 26 (68,4%) have been satisfied with particularly resolved implant but 13 (34.2) patients want to add some PLA gel as injection for penile girth recovery. Conclusions Thus, modern implants can improve the size and appearance of the penis, improve the quality of sexual life and the feeling of self-sufficiency in operated men. The use of silicone implants is simpler, it require only long drain 3–5 days. Most of operated patients were satisfied results of silicone implant. The use of a polymer matrix impregnated with autologuous stem cells requires a special biostem cell laboratory, more time for preoperative rehabilitation, but can be considered as more philological. Both methods can be considered as permanent and quite safe for penis enlargement. Disclosure No.

Preparation of porous polylactic acid nanofibers and application in non-electret high-efficiency filtration composites.

Air pollution caused by fine particulate matter (PM0.3) has drawn increasing attention as an overwhelming threat to public health. Electret treatment is commonly used to improve the filtration performance of commercial fibrous filter materials by enhancing the electrostatic adsorption effect, but it is greatly affected by environmental factors (especially humidity). Moreover, filter materials are generally non-degradable and non-recyclable, causing serious environmental pollution. Herein, a strategy to manufacture fully degradable polylactic acid (PLA) filtration composites based on porous PLA nanofibers prepared by electrospinning was investigated in this study. Porous, bead-on-string and conventional PLA nanofibers could be obtained by adjusting spinning condition parameters. The porous PLA nanofibers exhibited 9.8 times greater specific surface area (24.01 m2 g-1) and 18 times more cumulative pore volume (0.108 cm3 g-1) than conventional PLA nanofibers. More importantly, fibrous filtration composites based on porous PLA nanofibers possessed a high PM0.3 filtration efficiency (99.9989%), low pressure drop (90.35 Pa) and high air permeability (72.4 Pa-1) at an air flow rate of 32 L min-1 without electret treatment. The fibrous filtration composites based on conventional or bead-on-string PLA nanofibers also exhibited excellent filtration performance (>99.99%), but the associated high pressure drop and low air permeability limited their application.

Switchable surface and loading/release of target molecules in hierarchically porous PLA nonwovens based on shape memory effect.

In this work, hierarchically porous PLA (polylactic acid) shape memory nonwovens were prepared by electrospinning its blend solution with PEO (polyethylene oxide) and subsequent water etching. Based on shape memory effect resulting from tiny crystals and the amorphous matrix of PLA, the switch between compact and porous surfaces has been achieved via cyclical hot-pressing and recovery in a hot water bath. After hot-pressing, the disappearance of hierarchical pores contributes to compact surface, enabling embedding of the target molecule in PLA nonwoven (i.e., CLOSE state). Upon exposure to heat, PLA nonwoven recovers to its permanent shape and exhibits a porous surface, providing a penetrative diffusion pathway for small molecules (i.e., OPEN state). The hierarchically porous structure and shape memory effect endow PLA nonwoven with the capability of rapid release. Our results provide a good candidate for some potential applications, such as temperature-controlled quick-release of catalysts and drugs.

Combustion Performance of Various Polylactic Acid Plastics with Different Porous Structures Constructed by 3D Printing

Polylactic acid (PLA) has intrigued widespread attention as a biodegradable and environmentally friendly polymer, and recent research has revealed that the use of porous PLA in heat sinks for thermal management materials offers promising development potential. However, the heat transfer performance is closely related to its structure theoretically, whether it is virgin, and how the pore structure affects its heat transfer. Therefore, a novel approach is proposed to address this issue by preparing porous PLA through 3D printing at low complexity and cost, the combustion performance is employed to evaluate the heat transfer indirectly, and the higher burning speed represents higher efficient heat transfer. A new framework is developed to investigate combustion performance and three series of PLA with different pore structures in pore shape, size, and interval are studied by combining experimental tests, respectively. It demonstrates that adjusting the pore structure of PLA significantly alters its combustion performance, evidenced by significant variations in flame growth index, which are 83% better for the 2 mm holes than the largest holes and 71% better for the 2 mm interval than for the sparsest pore structure. Generally, it provides some experimental basis for designing porous thermal management materials; the various pore structures generate different combustion performances, corresponding to various heat transfer.

Optimized infill density through topological optimization increases strength of additively manufactured porous polylactic acid

Optimized infill density through topological optimization increases strength of additively manufactured porous polylactic acid

Controlling degree of foaming in extrusion 3D printing of porous polylactic acid

PurposeThis paper aims to understand the effect of extrusion conditions on the degree of foaming of polylactic acid (PLA) during three-dimensional (3D) printing. It was also targeted to optimize the slicing parameters for 3D printing and to study how the properties of printed parts are influenced by the extrusion conditions.Design/methodology/approachThis study used a commercially available PLA filament that undergoes chemical foaming. An extrusion 3D printer was used to produce individual extrudates and print samples that were characterized using an optical microscope, scanning electron microscope and custom in-house apparatuses.FindingsThe degree of foaming of the extrudates was found to strongly depend on the extrusion temperature and the material feed speed. Higher temperatures significantly increased the number of nucleation sites for the blowing agent as well as the growth rate of micropores. Also, as the material feed speed increased, the micropores were allowed to grow bigger which resulted in higher degrees of foaming. It was also found that, as the degree of foaming increased, the porous parts printed with optimized slicing parameters were lightweight and thermally less conductive.Originality/valueThis study fills the gap in literature where it examines the foaming behavior of individual extrudates as they are extruded. By doing so, this work distinguishes the effect of extrusion conditions from the effect of slicing parameters on the foaming behavior which enhances the understanding of extrusion of chemically foamed PLA.

Stabilization of Iron (0) in plasma treated semi porous polylactic acid based particles for in situ groundwater remediation

This study aims at incorporating reactive zero valent iron (ZVI) nanoparticles into water dispersible, biodegradable polymeric particles acting as a slow release reservoir of ZVI for targeting groundwater contaminants in situ. In order to accomplish the goal, three simple steps were adopted such as: 1) electrojetting of PLA (polylactic acid) with FeCl3 (∼17 wt%) to yield ∼700 nm sized monodisperse spherical particles (PLA_FeCl3) 2) surface modification of PLA_FeCl3 particles using oxygen plasma to enhance surface hydrophilicity and porosity (∼ 75%) 3) reduction of plasma treated PLA_FeCl3 particles in presence of NaBH4 to produce ZVI (size: 20–50 nm) entrapped PLA particles (PLA_ZVI) with high encapsulation efficiency of iron (∼85%). The plasma treated semi-porous PLA_ZVI particles exhibited slow and sustain release of iron (∼90% in ∼100 hrs) that were further employed to completely decontaminate both methyl orange (hydrophilic dye) and trichloroethylene (hydrophobic waste). Interestingly, the plasma treated particles were recyclable up to fourth batch, whereas the non-plasma treated one hardly show any recyclability due to burst release of surface entrapped iron from the latter. Moreover, the plasma treated hydrophilic particles provided stable dispersion (96 hrs) and prolonged reactivity (∼10 days in sand column) in water as opposed to non-plasma treated particles displaying 1 min dispersion stability in water. As a result, the plasma treated particles displayed smooth transportability through sand column (>80%) with negligible attachment efficiency (α = 1.1) onto sand particles. These attributes make them a potential alternative to bare ZVI (transportability <20%) for targeting hazardous pollutants by injecting them in groundwater.

Preparation of controllable micro-nano fiber bundle asymmetric porous PLA-PPC ethyl acetate driving film by pre-freezing treatment

The intelligent organic solvent actuator can effectively avoid direct contact in hazardous environment, which has important research significance in the fields of soft robots, intelligent devices and sensing. The structure of organic solvent actuators usually has asymmetrical structure, but the preparation process of such structure is complex and difficult to realize. Herein, based on the wettability difference of polymers, the asymmetric porous polylactic acid (PLA)- poly propylene carbonate (PPC) driving films with micro-nano fiber bundles were prepared by the simple pre-freezing treatment. The ultra-fast reversible intelligent deformation response behavior was triggered in ethyl acetate solvent. The deformation properties, surface morphology and pore size could be adjusted by the preparation process (pre-freezing temperature and PPC content). The PLA-PPC film was prepared at −7 °C with 0.85 wt% PPC content. After being soaked in solvent for 3 s, the maximum bending degree (360°) and curvature (1.9 cm−1) were obtained. The potential application scenarios of intelligent driving materials were provided, the driving film was designed as bionic flower, artificial butterfly, gripper driver and controllable circuit switch, which proved the feasibility of driving film in practical applications.

Janus porous polylactic acid membranes with versatile metal–phenolic interface for biomimetic periodontal bone regeneration

Conventional treatment to periodontal and many other bone defects requires the use of barrier membranes to guided tissue regeneration (GTR) and guided bone regeneration (GBR). However, current barrier membranes normally lack of the ability to actively regulate the bone repairing process. Herein, we proposed a biomimetic bone tissue engineering strategy enabled by a new type of Janus porous polylactic acid membrane (PLAM), which was fabricated by combining unidirectional evaporation-induced pore formation with subsequent self-assembly of a bioactive metal–phenolic network (MPN) nanointerface. The prepared PLAM-MPN simultaneously possesses barrier function on the dense side and bone-forming function on the porous side. In vitro, the presence of MPN nanointerface potently alleviated the proinflammatory polarization of mice bone marrow-derived macrophages (BMDMs), induced angiogenesis of human umbilical vein endothelial cells (HUVECs), and enhanced the attachment, migration and osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). The implantation of PLAM-MPN into rat periodontal bone defects remarkably enhanced bone regeneration. This bioactive MPN nanointerface within a Janus porous membrane possesses versatile capacities to regulate cell physiology favoring bone regeneration, demonstrating great potential as GTR and GBR membranes for clinical applications.

Additive manufacturing of bionanomaterials for biomedical applications based on TI6AL4V and PLA: a systematic review

Additive manufacturing (AM) is the owner of a huge potential as a manufacturing technology in fabricating functional implants, and scaffolds for biomedical applications. AM, which includes 3D printing (3DP) and 3D bioprinting, can be the solution to produce several needs such as scaffolds/implants, tissue or organs, or medical devices by combining different biomaterials with nanomaterials. Titanium and its alloys and Polylactic acid (PLA) are commonly used in bone tissue repair with their superior bio-functionality. The rapid advancement of three-dimensional (3D) printing technology has enabled the fabrication of porous titanium and polymer composite scaffolds with controllable microstructures, which is regarded as an effective method for promoting rapid bone repair. An electronic literature search was conducted in PubMed, Web of Science, Scopus, Elsevier, Embase, and other numerous databases up to December 2021 which are accessed by Karabuk university. To evaluate the possibility of bias and methodological quality, the SYRCLE tool and the last version of the CAMARADES list were used, respectively, a meta-analysis could not be performed. This systematic review is aimed to evaluate the common biomedical potential of 3D-printed porous Ti6Al4V (Ti64) and PLA matrix scaffold for repairing bone defects to investigate the influential factors that might affect its osteogenic availability. The most ideal parameters for designing the Ti64 scaffold were found to be a pore size of around 300-400 m and porosity of 60-70%, while PLA scaffolds show 350-400 m and nearly the same percentage in porosity as Ti64.

Fabrication of magnesium-doped porous polylactic acid microsphere for bone regeneration.

Biodegradable polymer microspheres that can be used as drug carriers are of great importance in biomedical applications, however, there are still challenges in controllable preparation of microsphere surface morphology and improvement of bioactivity. In this paper, firstly, poly(L-lactic acid) (PLLA) was synthesised by ring-opening polymerisation under anhydrous anaerobic conditions and further combined with the emulsion method, biodegradable PLLA microspheres (PM) with sizes ranging from 60-100 μm and with good sphericity were prepared. In addition, to further improve the surface morphology of PLLA microspheres and enhance their bioactivity, functionalised porous PLLA microspheres loaded with magnesium oxide (MgO)/magnesium carbonate (MgCO3) (PMg) were also prepared by the emulsion method. The results showed that the loading of MgO/MgCO3 resulted in the formation of a porous structure on the surface of the microspheres (PMg) and the dissolved Mg2+ could be released slowly during the degradation of microspheres. In vitro cellular experiments demonstrated the good biocompatibility of PM and PMg, while the released Mg2+ further enhanced the anti-inflammatory effect and osteogenic activity of PMg. Functionalised PMg not only show promise for controlled preparation of drug carriers, but also have translational potential for bone regeneration.

In vitro biodegradation, cytotoxicity, and biocompatibility of polylactic acid/napier cellulose nanofiber scaffold composites

This study aimed to evaluate the bioactivities and biocompatibilities of porous polylactic acid (PLA) reinforced with cellulose nanofiber (CNF) scaffolds. The in vitro degradation behaviors of the porous PLA/CNF scaffolds were systematically measured for up to 8 weeks in a phosphate-buffered saline medium at 37 °C. The reinforcement of CNF resisted the biodegradation of the scaffolds. The in vitro cytotoxicity and biocompatibility of the scaffolds were determined using the Beas2B American Type Culture Collection cells. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity and proliferation tests showed that the scaffolds were non-toxic, and epithelial cells grew well on the scaffold after 7 days of culture, whereas the percentage of cell proliferation on the PLA/CNF15 scaffold was the largest, 130 %. A scratch wound-healing assay was performed to evaluate the suitability of the scaffolds for cell migration. The results demonstrated that the scaffolds exhibited good cell migration towards nearly complete wound closure.