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Preparation and Characterization of Polymer Composite Materials Based on PLA/TiO2 for Antibacterial Packaging
摘要： Polymer composite materials based on polylactic acid (PLA) filled with titanium dioxide (TiO2) nanoparticles were prepared. The aim of this work was to investigate the antibacterial action of TiO2 against a strain of E. coli (DH5α) to obtain information on their potential uses in food and agro-alimentary industry. PLA/TiO2 systems were prepared by a two-step process: Solvent casting followed by a hot-pressing step. Characterization was done as a function of particle size (21 nm and <100 nm) and particle content (0%, 1%, 5%, 10%, and 20%, wt %). Structural characterization carried out by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FTIR) did not reveal significant changes in polymer structure due to the presence of TiO2 nanoparticles. Thermal characterization indicated that thermal transitions, measured by differential scanning calorimetry (DSC), did not vary, irrespective of size or content, whereas thermogravimetric analysis (TGA) revealed a slight increase in the temperature of degradation with particle content. Bacterial growth and biofilm formation on the surface of the composites against DH5α Escherichia coli was studied. Results suggested that the presence of TiO2 nanoparticles decreases the amount of extracellular polymeric substance (EPS) and limits bacterial growth. The inhibition distances estimated with the Kirby-Bauer were doubled when 1% TiO2 nanoparticles were introduced in PLA, though no significant differences were obtained for higher contents in TiO2 NPs.
关键词： antibacterial packaging,polylactic acid (PLA),polymer nanocomposites,TiO2 nanoparticles
更新于2025-09-23 15:22:29
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Thermal Characterization of a PPy/PLA Composite by Photoacoustic Calorimetry and Photopyroelectric Techniques
摘要： Recently, conductive polymers have attracted attention in the field of advanced materials. Conducting polymers include polypyrrole (PPy), which is a material with commercial applications due to its stability and electrical conductivity. As technology demands increasingly flexible devices, PPy was mixed with a biodegradable and flexible polymer, polylactic acid, in order to create a composite possessing of newer properties. As it is a new material, thermal properties of this composite such as thermal diffusivity, thermal effusivity, specific heat capacity, and thermal conductivity have been investigated through the application of photoacoustic calorimetry and photopyroelectric techniques.
关键词： PPy/PLA composite,Photoacoustic calorimetry,Polymer,Photopyroelectric technique
更新于2025-09-23 15:22:29
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Design of novel self-healing thermoplastic vulcanizates utilizing thermal/magnetic/light triggered shape memory effects
摘要： We designed novel self-healing thermoplastic vulcanizates (TPVs), achieving excellent thermal/magnetic/light triggered shape memory assisted self-healing behavior. Damage on polylactide (PLA)/epoxidized natural rubber (ENR)/Fe3O4 TPVs could be healed via three events synergistically: The shape memory effect of TPVs resulted in the physical contact of damaged surfaces; the desorption-absorption of ENR/Fe3O4 bound rubber promoted inter-diffusion of ENR chains, leading to the self-healing of ENR phase; ENR was grafted onto PLA segment to assist PLA rearranging and entangling again to achieve the repair of TPVs. This self-healing TPV was reported for the first time and paved the way to design next-generation self-healing materials.
关键词： multi-stimuli response,self-healing,PLA/ENR,thermoplastic vulcanizates,shape memory effect
更新于2025-09-23 15:21:01
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Printed Soft Optical Waveguides of PLA Copolymers for Guiding Light into Tissue
摘要： The application of optical technologies in treating pathologies and monitoring disease states requires the development of soft, minimal invasive and implantable devices to deliver light to tissues inside the body. Here we present soft and degradable optical waveguides from poly(D,L-lactide) and derived copolymers fabricated by extrusion printing in desired dimensions and shapes. The obtained optical waveguides propagate VIS to NIR light in air and in tissue at penetration depths of tens of centimeters. Besides, the printed waveguides have elastomeric properties at body temperature and show softness and flexibility in the range relevant for implantable devices in soft organs. Printed waveguides were able to guide light across 8 cm tissue and activate photocleavage chemical reactions in a photoresponsive hydrogel (in vitro). The simplicity and flexibility of the fiber processing method, and the optical and mechanical performance of the obtained waveguides exemplify how rational study of medically approved biomaterials can lead to useful inks for printing cost-effective and flexible optical components for potential use in medical contexts.
关键词： soft optical waveguides,printed PLA,printed Resomer?,light guidance,photoactivation in tissues,polymeric optical waveguides,printed optical materials
更新于2025-09-19 17:13:59
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Photoluminescent functionalized carbon quantum dots loaded electroactive Silk fibroin/PLA nanofibrous bioactive scaffolds for cardiac tissue engineering and nursing care application
摘要： Tissue engineering and stem cell rehabilitation are the hopeful aspects that are being investigated for the management of Myocardial Infarction (MI); cardiac patches have been used to start myocardial rejuvenation. In this study, we engineered p-phenylenediamine surface functionalized (modif-CQD) into the Silk fibroin/PLA (SF/PLA) nanofibrous bioactive scaffolds with improved physico-chemical abilities, mechanical and cytocompatibility to cardiomyocytes. The micrograph results visualized the morphological improved spherical modif-CQD have been equivalently spread throughout the SF/PLA bioactive cardiac scaffolds. The fabricated CQD@SF/PLA nanofibrous bioactive scaffolds were highly porous with fully consistent pores; effectively improved young modulus and swelling asset for the suitability and effective implantation efficacy. The scaffolds were prepared with rat cardiomyocytes and cultured for up to 7 days, without electrical incentive. After 7 days of culture, the scaffold pores all over the construct volume were overflowing with cardiomyocytes. The metabolic activity and viability of the cardiomyocytes in CQD@SF/PLA scaffolds were significantly higher than cardiomyocytes in Silk fibroin /PLA scaffolds. The integration of CQD also influenced greatly and increases the expression of cardiac- marker genes. The results of the present investigations evidently recommended that well-organized cardiac nanofibrous scaffold with greater cardiac related mechanical abilities and biocompatibilities for cardiac tissue engineering and nursing care applications.
关键词： Scaffolds,PLA,Carbon Quantum Dots,Silk fibroin
更新于2025-09-16 10:30:52
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Creation of shuttle-shaped nanoparticles using the method of magnetic polarization pulse laser ablation
摘要： The GaxCo0.6-xZnS0.4 (x = 0.1, 0.3, 0.5) nanoparticles with shuttle-shaped are fabricated via a Magnetic Polarization Pulse Laser Ablation (MPPLA) method. Meanwhile, the circular-shaped nanoparticles also are prepared for comparative analysis. The particle size, structure, and valence state are systematically investigated by X-ray di?raction (XRD), Raman spectra and X-ray photoelectron spectroscopy (XPS). The morphology of the nanoparticles characterized by TEM indicating the high e?cient of shuttle-shaped particles in preparation. A physical model of the e?ect of magnetic ?eld on the plasma plume is established to explain the formation of shuttle-shaped nanoparticles. Then, we present an explosion-absorption model to demonstrate the growth mechanism of nanoparticles. We further discuss the cluster phenomena and summarized three types of clusters in our nanoparticle suspensions. Fluorescence properties are re?ected by PL spectra, which demonstrates the best performance in concentration of GaxCo0.6-xZnS0.4 with shuttle-shaped. Therefore, all the results suggest that MPPLA is promising to prepare nanoparticles since it can adjust the shape, solve the cluster and modulate performance of NPs.
关键词： PLA,Chalcogenide,Magnetic Polartzation,Nanoparticles
更新于2025-09-11 14:15:04
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Doxorubicin-loaded protease-activated near-infrared fluorescent polymeric nanoparticles for imaging and therapy of cancer
摘要： Despite significant progress in the field of oncology, cancer remains one of the leading causes of death. Chemotherapy is one of the most common treatment options for cancer patients but is well known to result in off-target toxicity. Theranostic nanomedicines that integrate diagnostic and therapeutic functions within an all-in-one platform can increase tumor selectivity for more effective chemotherapy and aid in diagnosis and monitoring of therapeutic responses. Material and methods: In this work, theranostic nanoparticles were synthesized with commonly used biocompatible and biodegradable polymers and used as cancer contrast and therapeutic agents for optical imaging and treatment of breast cancer. These core–shell nanoparticles were prepared by nanoprecipitation of blends of the biodegradable and biocompatible amphiphilic copolymers poly(lactic-co-glycolic acid)-b-poly-l-lysine and poly(lactic acid)-b-poly(ethylene glycol). Poly-l-lysine in the first copolymer was covalently decorated with near-infrared fluorescent Alexa Fluor 750 molecules. Results: The spherical nanoparticles had an average size of 60–80 nm. The chemotherapeutic drug doxorubicin was encapsulated in the core of nanoparticles at a loading of 3% (w:w) and controllably released over a period of 30 days. A 33-fold increase in near-infrared fluorescence, mediated by protease-mediated cleavage of the Alexa Fluor 750-labeled poly-l-lysine on the surface of the nanoparticles, was observed upon interaction with the model protease trypsin. The cytocompatibility of drug-free nanoparticles and growth inhibition of drug-loaded nanoparticles on MDA-MB-231 breast cancer cells were investigated with a luminescence cell-viability assay. Drug-free nanoparticles were found to cause minimal toxicity, even at high concentrations (0.2–2,000 μg/mL), while doxorubicin-loaded nanoparticles significantly reduced cell viability at drug concentrations .10 μM. Finally, the interaction of the nanoparticles with breast cancer cells was studied utilizing fluorescence microscopy, demonstrating the potential of the nanoparticles to act as near-infrared fluorescence optical imaging agents and drug-delivery carriers. Conclusion: Doxorubicin-loaded, enzymatically activatable nanoparticles of less than 100 nm were prepared successfully by nanoprecipitation of copolymer blends. These nanoparticles were found to be suitable as controlled drug delivery systems and contrast agents for imaging of cancer cells.
关键词： enzymatic activation,nanoprecipitation,theranostics,PEG,poly-l-lysine,PLGA,block copolymers,nanomedicine,fluorescence imaging,drug delivery,nanoparticles,PLA
更新于2025-09-10 09:29:36
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Quantitative Determination of Fluorine Content in Blends of Polylactide (PLA)–Talc Using Near Infrared Spectroscopy
摘要： Near-infrared spectroscopy (NIRS) has been widely used for quantitative and/or qualitative determination of a wide range of matrices. The objective of this study was to develop a NIRS method for the quantitative determination of fluorine content in polylactide (PLA)-talc blends. A blending profile was obtained by mixing different amounts of PLA granules and talc powder. The calibration model was built correlating wet chemical data (alkali digestion method) and NIR spectra. Using FT (Fourier Transform)-NIR technique, a Partial Least Squares (PLS) regression model was set-up, in a concentration interval of 0 ppm of pure PLA to 800 ppm of pure talc. Fluorine content prediction (R2 cal = 0.9498; standard error of calibration, SEC = 34.77; standard error of cross-validation, SECV = 46.94) was then externally validated by means of a further 15 independent samples (R2 EX.V = 0.8955; root mean standard error of prediction, RMSEP = 61.08). A positive relationship between an inorganic component as fluorine and NIR signal has been evidenced, and used to obtain quantitative analytical information from the spectra.
关键词： quantitative calibration,fluorine,PLA,polylactide,blends,talc,near infrared spectroscopy
更新于2025-09-04 15:30:14