A Perspective on Polylactic Acid-Based Polymers Use for Nanoparticles Synthesis and Applications

Medina D.X., Chung E.P., Bowser R., Sirianni R.W.

Small molecule retinoids are potential therapeutics for a variety of neurological diseases. However, most retinoids are poorly water soluble and difficult to deliver in vivo, which prevents further study of their utility to treat disease. Here, we focus on adapalene, an FDA approved drug that is a specific agonist for the retinoic acid receptor β (RARβ). We sought to develop nanoparticle delivery systems that would enable effective delivery of adapalene to the CNS. We developed strategies to produce nanoparticles based on the hypothesis that incorporation of hydrophobic molecules into a polyester base would improve adapalene loading. In the first scheme, poly (lactic acid)-poly (ethylene glycol) (PLA-PEG) was blended with low molecular weight poly (lactic acid) (PLA) or poly (caprolactone) (PCL). In the second scheme, poly (lactic-co-glycolic acid) (PLGA) was blended with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol) (DSPE-PEG). Our data demonstrate that blending low molecular weight polyesters or DSPE-PEG into the primary nanoparticle base improves encapsulation of adapalene, presumably by enhancing adapalene solubility in the nanoparticle. Peripheral administration of these nanoparticles activated retinoid signaling in the brain and spinal cord of healthy mice. These studies provide new approaches for nanoparticle fabrication and establish proof of principle that systemically administered, adapalene-loaded nanoparticles activate retinoid signaling in the CNS.

Partikel K., Korte R., Stein N.C., Mulac D., Herrmann F.C., Humpf H., Langer K.

Upon intravenous administration of nanoparticles (NP) into the bloodstream, proteins bind rapidly on their surface resulting in a formation of a so-called 'Protein Corona'. These proteins are strongly attached to the NP surface and provide a new biological identity which is crucial for the reaction at the nano-biointerface. The structure and composition of the protein corona is greatly determined by the physico-chemical properties of the NP and the characteristics of the biological environment. The overall objective of this study was to characterize the role of NP size/surface curvature and PEGylation on the formation of the protein corona. Therefore, we prepared NP in a size of 100 and 200 nm using the biodegradable polymers poly(DL-lactide-co-glycolide) (PLGA) and poly(DL-lactide-co-glycolide)-co-polyethylene glycol diblock (PLGA-PEG) and subsequently incubated them with fetal bovine serum (FBS) to induce the formation of a protein corona. After removal of unbound protein, we employed different analytical approaches to study the corona in detail. Sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) was performed to gain a first impression about amount and composition of the corona proteins. Identification was carried out after tryptic in-solution digestion and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). In addition, we successfully established the Bradford protein assay as a suitable colorimetric method to quantify total adsorbed protein amount after alkaline hydrolysis of PLGA based NP. Our results revealed that protein adsorption on PLGA- and PLGA-PEG-NP didn't depend on NP size within the range of 100 and 200 nm. PEGylation led to a significant reduced amount of bound proteins. The depletion of proteins which are involved in immune response was remarkable and indicated a prolonged circulation time in body.

Kim K., Lee J., Kim D., Yoon I., Cho H.

Diverse nanosystems for use in cancer imaging and therapy have been designed and their clinical applications have been assessed. Among a variety of materials available to fabricate nanosystems, poly(lactic-co-glycolic acid) (PLGA) has been widely used due to its biocompatibility and biodegradability. In order to provide tumor-targeting and diagnostic properties, PLGA or PLGA nanoparticles (NPs) can be modified with other functional materials. Hydrophobic or hydrophilic therapeutic cargos can be placed in the internal space or adsorbed onto the surface of PLGA NPs. Protocols for the fabrication of PLGA-based NPs for cancer imaging and therapy are already well established. Moreover, the biocompatibility and biodegradability of PLGA may elevate its feasibility for clinical application in injection formulations. Size-controlled NP’s properties and ligand–receptor interactions may provide passive and active tumor-targeting abilities, respectively, after intravenous administration. Additionally, the introduction of several imaging modalities to PLGA-based NPs can enable drug delivery guided by in vivo imaging. Versatile platform technology of PLGA-based NPs can be applied to the delivery of small chemicals, peptides, proteins, and nucleic acids for use in cancer therapy. This review describes recent findings and insights into the development of tumor-targeted PLGA-based NPs for use of cancer imaging and therapy.

Da Silva J., Jesus S., Bernardi N., Colaço M., Borges O.

Polylactic acid (PLA), a biodegradable and biocompatible polymer produced from renewable resources, has been widely used as a nanoparticulate platform for antigen and drug delivery. Despite generally regarded as safe, its immunotoxicological profile, when used as a polymeric nanoparticle (NP), is not well documented. Thus, this study intends to address this gap, by evaluating the immunotoxicity of two different sized PLA NPs (PLAA NPs and PLAB NPs), produced with different nanoprecipitation methods and extensively characterized regarding their physicochemical properties in in vitro experimental conditions. After production, PLAA NPs mean diameter was superior to PLAB NPs. Interestingly, when in RPMI medium, both presented similar mean size and zeta potential, possibly explaining the similarity between their cytotoxicity profile in PBMCs. On the other hand, in DMEM medium, PLAA NPs presented smaller mean diameter, which may explain its higher toxicity in RAW 264.7. Likewise, PLAA NPs induced a higher dose-dependent ROS production, which can explain their toxicity in this cell line. Irrespective of size differences, none of the PLA NPs presented an inflammatory potential characterized by NO production or a hemolytic activity in human blood. The results herein presented suggest that smaller PLA NPs (

George A., Shah P.A., Shrivastav P.S.

Nanomedicines are now considered as the new-generation medication in the current era mainly because of their features related to nano size. The efficacy of many drugs in their micro/macro formulations is shown to have poor bioavailability and pharmacokinetics after oral administration. To overcome this predicament, use of natural/synthetic biodegradable polymeric nanoparticles (NPs) have gained prominence in the field of nanomedicine for targeted drug delivery to improve biocompatibility, bioavailability, safety, enhanced permeability, better retention time and lower toxicity. For drug delivery, it is essential to have biodegradable nanoparticle formulations for safe and efficient transport and release of drug at the intended site. Moreover, depending on the target organ, a suitable biodegradable polymer can be selected as the drug-carrier for target specific as well as for sustained drug delivery. The aim of this review is to present the current status and scope of natural biodegradable polymers as well as some emerging polymers with special characteristics as suitable carriers for drug delivery applications. The most widely preferred preparation methods are discussed along with their characterization using different analytical techniques. Further, the review highlights significant features of methods developed using natural polymers for drug entrapment and release studies.

Coolen A., Lacroix C., Mercier-Gouy P., Delaune E., Monge C., Exposito J., Verrier B.

Messenger RNA-based vaccines have the potential to trigger robust cytotoxic immune responses, which are essential for fighting cancer and infectious diseases like HIV. Dendritic Cells (DCs) are choice targets for mRNA-based vaccine strategies, as they link innate and adaptive immune responses and are major regulators of cytotoxic and humoral adaptive responses. However, efficient delivery of antigen-coding mRNAs into DC cytosol has been highly challenging. In this study, we developed an alternative to lipid-based mRNA delivery systems, using poly(lactic acid) nanoparticles (PLA-NPs) and cationic cell-penetrating peptides as mRNA condensing agent. The formulations are assembled in two steps: (1) formation of a polyplex between mRNAs and amphipathic cationic peptides (RALA, LAH4 or LAH4-L1), and (2) adsorption of polyplexes onto PLA-NPs. LAH4-L1/mRNA polyplexes and PLA-NP/LAH4-L1/mRNA nanocomplexes are taken up by DCs via phagocytosis and clathrin-dependent endocytosis, and induce strong protein expression in DCs in vitro. They modulate DC innate immune response by activating both endosome and cytosolic Pattern Recognition Receptors (PRRs), and induce markers of adaptive responses in primary human DCs in vitro, with prevalent Th1 signature. Thus, LAH4-L1/mRNA and PLA-NP/LAH4-L1/mRNA represent a promising platform for ex vivo treatment and mRNA vaccine development.

Michalski A., Brzezinski M., Lapienis G., Biela T.

The syntheses, properties and selected applications of star-shaped polymers with arms composed of homo- or copolymers of polylactide (PLA) is reviewed. The star-shaped (including miktoarm stars), dendritic, and branched polymers with a specified or varying numbers of arms were synthesized depending on the applied core molecule. Examples of a large number of various structures of star-shaped PLA polymers are precisely described. The growing interest in the synthesis of star-shaped and branched PLAs is primarily motivated by their potential applications in the biomedical and pharmaceutical areas. Therefore, the thermal, rheological, and mechanical properties, as well as various applications, of PLA stars as, for example, drug carriers, medical materials, and components of hydrogels, are also reported.

Hamad K., Kaseem M., Ayyoob M., Joo J., Deri F.

Polylactic acid (PLA) is a biobased product and a compostable aliphatic polyester that has been studied for use in several applications over the last decade. Many properties of PLA, such as strength, stiffness, and gas permeability, have been found to be comparable to those of traditional petrochemical-based polymers. However, PLA-based materials exhibit a number of limitations for specific applications, such as slow biodegradation rate, high cost, and low toughness. The modification of PLA using the polymer blending technique to achieve suitable properties for different applications has been receiving significant attention over the past few years. Hence, the aim of this work is to summarize the current developments regarding the preparation and properties of PLA polymer blends. In this review, the recent advances in PLA preparation are broadly introduced. In addition, the miscibility and compatibilization strategies of PLA polymer blends are discussed. The preparations and characterizations of PLA blends with both biodegradable and non-biodegradable polymers are outlined. Finally, the biodegradation, mechanical properties, and potentiality of PLA blends are presented.

Armentano I., Gigli M., Morena F., Argentati C., Torre L., Martino S.

In the last decade, biopolymer matrices reinforced with nanofillers have attracted great research efforts thanks to the synergistic characteristics derived from the combination of these two components. In this framework, this review focuses on the fundamental principles and recent progress in the field of aliphatic polyester-based nanocomposites for regenerative medicine applications. Traditional and emerging polymer nanocomposites are described in terms of polymer matrix properties and synthesis methods, used nanofillers, and nanocomposite processing and properties. Special attention has been paid to the most recent nanocomposite systems developed by combining alternative copolymerization strategies with specific nanoparticles. Thermal, electrical, biodegradation, and surface properties have been illustrated and correlated with the nanoparticle kind, content, and shape. Finally, cell-polymer (nanocomposite) interactions have been described by reviewing analysis methodologies such as primary and stem cell viability, adhesion, morphology, and differentiation processes.

Ganguly P., Breen A., Pillai S.C.

Growth in production of manufactured goods and the use of nanomaterials in consumer products has mounted in the past few decades. Nanotoxicology or toxicity assessment of these engineered products is required to understand possible adverse effects and their fate inside the human body. The present review is a one stop assessment intended to be a state of the art understanding on nanotoxicity. It provides a summation of the various kinds of cell death and also discusses the different types of toxicities along with their studies. The review discusses the physiological impact imparted on cells (reactive oxygen species generation and the resultant oxidative stress, inflammation, and other nonoxidant pathways). Moreover, it discusses the different physicochemical properties of nanomaterials (size, morphology, surface charge, and coating) governing the cytotoxicity properties. It also details the major pathways of nanomaterial uptake in cells and their outcome. Additionally, it also discusses the possible method...

Tang B., Zaro J.L., Shen Y., Chen Q., Yu Y., Sun P., Wang Y., Shen W., Tu J., Sun C.

Cell-penetrating peptides (CPPs) have become a novel drug delivery system due to their distinct advantages, including high cell transmembrane potency and ability to carry cargo molecules inside cells. However, owing to their cationic charge and non-specificity characteristics, the clinical application of CPPs is limited. In the current study, we engineered a reversibly activatable cell-penetrating peptide (RACPP), containing oligoarginine fused to a pH-sensitive masking sequence via a polyglycine linker ((HE)10G5R6 or HE-CPP) with ultra-pH-sensitivity. The HE-CPP sequence was coupled to the surface of polyethyleneglycol-polylactic acid (PEG-PLA) polymer micelles (PMs-HE-CPP) to realize improve specificity and targeted delivery of encapsulated paclitaxel (PTX). PTX/PMs-HE-CPP showed the satisfactory encapsulated efficiency, loading capacity, size distribution as well as reversible charge-conversion in response to the surrounding pH. The zeta potential of PMs-HE-CPP was negative at pH 7.5, moderately positive at pH 6.5, and even more positive at a lower pH. Coumarin 6-loaded PMs-HE-CPP (C6/PMs-HE-CPP) showed enhanced tumor cellular uptake at a mildly acidic tumor microenvironment (pH 6.5) via energy-dependent and clathrin-mediated endocytosis. Furthermore, PTX/PMs-HE-CPP had significantly higher cytotoxicity toward mice breast cancer (4T1) cells at pH 6.5 versus at pH 7.4. In vivo imaging studies in 4T1-BALB/c tumor xenograft models confirmed the tumor-targeting characteristic of PMs-HE-CPP. PTX/PMs-HE-CPP also exhibited improved anti-tumor efficacy against unmodified polymer micelles and Taxol® in this tumor model. Accordingly, not only do RACPPs show the great potential to endow CPPs with specificity and reversible net-charge converting characteristic, they are also able to improve the targeting effect of nanoparticles.

Zhou Q., Li Y., Zhu Y., Yu C., Jia H., Bao B., Hu H., Xiao C., Zhang J., Zeng X., Wan Y., Xu H., Li Z., Yang X.

Heterogeneous distribution of drug inside tumor is ubiquitous, causing regional insufficient chemotherapy, which might be the hotbed for drug resistance, tumor cell repopulation and metastasis. Herein, we verify, for the first time, that heterogeneous drug distribution induced insufficient chemotherapy would accelerate the process of epithelial mesenchymal transition (EMT), consequently resulting in the promotion of tumor metastasis. To eliminate the insufficient chemotherapy promoted metastasis, we conceived a co-delivery strategy by hydroxyethyl starch-polylactide (HES-PLA) nanoparticle, in which DOX and TGF-β receptor inhibitor, LY2157299 (LY), were administered together. In vitro and in vivo studies demonstrate that this co-delivery strategy can simultaneously suppress primary tumor and distant metastasis. Further study on immunofluorescence images of primary tumor verifies that low dose of DOX exasperates the EMT process, whereas the co-delivery nanoparticle can dramatically inhibit the progression of EMT. We reveal the impact of heterogeneous drug distribution on tumor metastasis and develop an effective co-delivery strategy to suppress the metastasis, providing guidance for clinical cancer therapy.

Raudszus B., Mulac D., Langer K.

Nanoparticles are promising drug delivery systems to overcome physiological barriers such as the blood-brain barrier. In this respect nanoparticle uptake into endothelial or epithelial cells is the first necessary step to overcome these obstacles. Therefore, a new strategy for the covalent attachment of drug targeting ligands on poly(lactic acid) (PLA) nanoparticles was developed and the influence of the resulting surface properties on the uptake behaviour in cerebral endothelial cells was investigated. PLA nanoparticles were modified on their surface by apolipoprotein E, penetratin, or ovalbumin using a newly developed vinyl sulfone-modified poly(vinyl alcohol)-derivative (VS-PVA) as steric stabilizer. With this approach an easy option for ligand coupling reactions to PVA-stabilized nanoparticles was achieved. All obtained formulations showed a favourable behaviour concerning cytotoxic effects on endothelial cells, not compromising their viability. Furthermore, a clear relation between cellular uptake and surface coupled functional ligand could be determined: Penetratin- and apolipoprotein E-modified nanoparticles showed a distinct higher cellular uptake than ovalbumin-modified or unmodified nanoparticles, which both can be explained by mechanistic reasons. Overall the use of the reactive VS-PVA as stabilizer for nanoparticle preparation is an universal and effective approach to couple several functional ligands to the particles' surface for targeting applications.

Crucho C.I., Barros M.T.

Since the emergence of Nanotechnology in the past decades, the development and design of nanomaterials has become an important field of research. An emerging component in this field is nanomedicine, wherein nanoscale materials are being developed for use as imaging agents or for drug delivery applications. Much work is currently focused in the preparation of well-defined nanomaterials in terms of size and shape. These factors play a significantly role in the nanomaterial behavior in vivo. In this context, this review focuses on the toolbox of available methods for the preparation of polymeric nanoparticles. We highlight some recent examples from the literature that demonstrate the influence of the preparation method on the physicochemical characteristics of the nanoparticles. Additionally, in the second part, the characterization methods for this type of nanoparticles are discussed.

dos Santos S.N., dos Reis S.R., Pinto S.R., Cerqueira-Coutinho C., Nigro F., Barja-Fidalgo T.C., Pinheiro N.M., Neto H.A., Santos-Oliveira R.

Despite advancements in treatment of infectious diseases, opportunistic pathogens continue to pose a worldwide threat. Identifying a source of infection/inflammation is often challenging which highlights the need of improved diagnostic agents. Using a model of local S. aureus infection, here we evaluated the potential of betamethasone or dexamethasone loaded in poly (lactic acid) nanoparticles and radiolabeled with 99mTc to detect an infection/inflammation site in vivo. A betamethasone and dexamethasone nanoparticles (NPs) with 200 and 220 nm in size, respectively, were created with a 98% 99mTc radiolabeling efficiency. When injected in infected mice, betamethasone NPs presented a higher accumulation in the infected hind paw in comparison with dexamethasone NPs. Our results suggest that this nanosystem may be a valid nanoradiopharmaceutical for the detection of inflammation/infection foci in vivo.

Lynn A.Y., Shin K., Eaton D.A., Rose M., Zhang X., Ene M., Grundler J., Deschenes E., Rivero R., Bracaglia L.G., Glazer P.M., Stitelman D.H., Saltzman W.M.

Martins N.C., Silva C.S., Pinto R.J., Trindade T.

Udana Eranda D.H., Chaijan M., Castro-Munoz R.

Santoro A., Voto A., Fortino L., Guida R., Laudisio C., Cillo M., D’Ursi A.M.

In recent years, the management of bone defects in regenerative medicine and orthopedic surgery has been the subject of extensive research efforts. The complexity of fractures and bone loss arising from trauma, degenerative conditions, or congenital disorders necessitates innovative therapeutic strategies to promote effective healing. Although bone tissue exhibits an intrinsic regenerative capacity, extensive fractures and critical-sized defects can severely compromise this process, often requiring bone grafts or substitutes. Tissue engineering approaches within regenerative medicine have introduced novel possibilities for addressing nonunions and challenging bone defects refractory to conventional treatment methods. Key components in this field include stem cells, bioactive growth factors, and biocompatible scaffolds, with a strong focus on advancements in bone substitute materials. Both natural and synthetic substitutes present distinct characteristics and applications. Natural grafts—comprising autologous, allogeneic, and xenogeneic materials—offer biological advantages, while synthetic alternatives, including biodegradable and non-biodegradable biomaterials, provide structural versatility and reduced immunogenicity. This review provides a comprehensive analysis of the diverse bone grafting alternatives utilized in orthopedic surgery, emphasizing recent advancements and persistent challenges. By exploring both natural and synthetic bone substitutes, this work offers an in-depth examination of cutting-edge solutions, fostering further research and innovation in the treatment of complex bone defects.

Gaglio S.C., Zanella G., Cazzaniga S., Olivieri N., Battagini E., Romeo A., Ballottari M., Perduca M.

Bikiaris N.D., Klonos P.A., Christodoulou E., Barmpalexis P., Kyritsis A.

Patience N.A., Jensen H.M., Banquy X., Boffito D.C.

AbstractPoly(d,l‐lactide) is a biocompatible and biodegradable polymer with applications in the biomedical field (drug delivery, implants) and packaging. Conventional synthesis with stannous octoate is slow (>4 h) and can climb to over 30 h. In order to reduce reaction times, we developed a microwave reactor process to ring‐open polymerize d,l‐lactide to form poly(d,l‐lactide) in the presence of stannous octoate and an initiator, benzyl alcohol. We evaluated the suitability of toluene and tetrahydrofuran as solvents at 130, 150, and 170°C for the polymerization. Their respective dielectric loss values are 0.1 and 0.35. Compounds with larger dielectric loss values are better at converting microwave energy to heat. The microwave's power input peaked at 420 W to reach 170°C with toluene, whereas with tetrahydrofuran the peak was 330 W; afterwards, the power input to maintain that temperature was 10 W for both solvents. A reaction in toluene at 170°C after 1 h produced poly(d,l‐lactide) with a molecular weight of 31 kDa and a dispersity index of 1.5. In tetrahydrofuran, at the same temperature, the molecular weight peaked at 11 kDa after 4 h with a dispersity index of 1.2. Moreover, in the absence of microwaves the polymerization does not occur. Tetrahydrofuran is hygroscopic and water cleaves poly(d,l‐lactide) chains resulting in a lower molecular weight despite the longer reaction time and larger dielectric loss compared to toluene, a water immiscible solvent.

Mousazadeh S.M., Allahyari S., Nokhodchi A.

Abstract Coronary artery blockage, the most common cardiovascular problem, is often treated with drug-eluting stents (DES). This study aims to address the main limitation of traditional angioplasty therapy. Thus, designing, fabricating, and analyzing a novel drug-eluting polymeric stent using liquid crystal display (LCD) technology may potentially represent an innovative approach to DES in the near future. Therefore, a poly (lactic acid) (PLA) based 3D-printed stent was designed using SolidWorks software and fabricated using the liquid crystal display (LCD) method. The cyclosporine-loaded stent was prepared and analyzed using optical microscopy, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Loading efficiency percentage and release characteristics were estimated. The polymeric stent platform was successfully designed and manufactured using PLA resin. Based on the characterization of cyclosporine eluting stent, a loading efficiency of 48.66 ± 5.92% was estimated through the immersion method. The FTIR and DSC results confirmed molecular interactions between cyclosporine and the PLA-based 3D-printed stent compared with physical mixture formulations. A sustained release profile of cyclosporine was also observed where approximately 50% of the drug was released within the first three hours. The sustained-release profile, characterized by the absence of a burst release, holds significant clinical potential by ensuring consistent therapeutic levels, reducing side effects, and potentially improving patient outcomes. Overall, the study highlights the effectiveness of LCD technology in printing the stent platform using PLA resin. The results demonstrated a significant cyclosporine loading with a sustained release profile without any stent coating procedure. Graphical Abstract

Xia H., Yang C., Li H., Huang L., Zeng Z., Chi R., Yang Z., Wang Y., Chang J., Jiao Y., Li W.

Abstract Muscle satellite cells (MuSCs) play a vital role in skeletal muscle regeneration. However, in intractable muscle diseases such as volumetric muscle loss (VML), the quantity and function of MuSCs are significantly reduced, severely limiting the body's inherent muscle regeneration capability. In this study, we propose a novel strategy to modulate the fate of MuSCs using a combination of bioactive magnesium (Mg) and silicon (Si) ions, sustainably delivered through magnesium silicate (MgSiO3, MS) bioceramic-based scaffolds. In vitro, Mg and Si ions synergistically promote the proliferation and differentiation of MuSCs. Similarly, Mg and Si ions derived from MS/poly (L-lactic acid) (MS/PLLA) composite scaffold also increases the proliferation and differentiation ability of MuSCs. Furthermore, MS/PLLA composite scaffolds facilitate the activation of MuSCs, regeneration of muscle fiber, and neovascularization, while inhibiting fibrosis, thereby effectively restoring muscle function and promoting tibialis anterior muscle functional regeneration in a VML mouse model. Mechanistically, the combination of Mg and Si ions promotes the activation and proliferation of MuSCs by activating the Notch1-Hes1 pathway. Besides, the combination of Mg and Si ions also improves the differentiation of MuSCs by up-regulating Myod and Myog, and enhances fusion by up-regulating Mymk and Mymx expression. The outcomes of our research introduce a promising approach to the treatment of skeletal muscle injuries and related diseases.

Bruckbauer A., Scofield G.B., Frisch T., Halloran M.W., Guan Z., Wnuk-Fink K.M., Allemann M.N., O’Shea K., Simkovsky R., Bae J., Mayfield S.P., Burkart M.D.

Gade H.M.

Gupta M., Singh A.

Medical devices play a significant role in the medical sector, and their needs are essential. These devices demand biocompatibility and bioabsorbable. Polymeric biocomposites developed using natural polymers are readily biodegradable, compostable, and recyclable and have the same properties as synthetic composites and other metallic composite. Polylactic acid (PLA) and Chitosan (CS) blend-based bio composites fulfill such requirements. These are bio-natural polymers that degrade naturally and have good mechanical strength. The primary aim of this work is to develop PLA/CS blend-based Hydroxyapatite (HAp) and Aluminum Oxide (Al2O3) bifiller-reinforced polymeric bio-nanocomposites (BRPBNCs). The development process involved solid compression technique, which allowed for development of these BRPBNCs with desired properties. A secondary objective of this work is characterization of developed BRPBNCs to study morphological, mechanical, water absorption, and thermal properties. The morphological characteristics were evaluated using Field Emission Scanning Electron Microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to analyze the surface properties. These studies show a proper dispersion of bifiller material into the PLA/CS blend-base BRPBNCs. Mechanical properties such as tensile and flexural strength, compression, impact test, and shore D hardness were examined per the American Society for Testing and Materials standards. The maximum tensile, flexural, impact, and shore D hardness values are 12.36 N/mm2, 27.18 N/mm2, 0.61 J, and 76.66, respectively, for the wt% of P/30CS-20HAp/2Al2O3, P/30CS-20HAp/3Al2O3, P/30CS-20HAp/1Al2O3, and P/30CS-20HAp/3Al2O3. Thermogravimetric (TGA) analysis was utilized to evaluate the thermal properties of PBNCs and check their ability to resist degradation at higher temperatures. Water barrier property is studied through water absorption analysis. The results suggest that the proposed BRPBNCs offer superior mechanical and thermal characteristics and are appropriate for medical internal fixation implant applications.

Wang X., Cao Z., Su J., Ge X., Zhou Z.

AbstractFood‐derived bioactive peptides are a class of peptides from natural protein. It may have biological effects on the human body and play a significant role in protecting human physiological health and regulating physiological metabolism, such as lowering blood pressure, lowering cholesterol, antioxidant, antibacterial, regulating immune activity, and so on. However, most of the natural food‐derived functional peptides need to overcome a variety of barriers in the body to enter the blood circulation system and target to specific tissues to generate physiological activity. During this process, the bioavailability of the functional peptides will be reduced. The nano‐delivery system can offer the feasibility to overcome these obstacles and improve the stability and bioavailability of food‐derived active peptides by nanoencapsulation. This work summarizes the application of food‐derived bioactive peptides and the obstacles during the delivery pathway in vivo. Moreover, the different nano‐delivery systems used for bioactive peptides and their application were summarized, which could provide ideas for oral delivery of food‐derived bioactive peptides.

Sun P., Liu K., Dong C., Yan L., Zhu H., Fang M., Fu D., Liu X.

Polylactic acid, a biodegradable polymer derived from renewable resources, is increasingly used in food packaging due to its transparency, renewability, and food safety. However, its mechanical properties, heat resistance, and barrier performance present significant challenges that limit its application. Currently, there is a lack of comprehensive literature addressing methods to optimize polylactic acid’s performance for various food packaging application. Hence, this review provides an overview of polylactic acid production processes, including the synthesis of lactic acid and lactide, as well as methods such as polycondensation and ring-opening polymerization. We critically examine the advantages and limitations of polylactic acid in various food packaging contexts, focusing on strategies to enhance its mechanical properties, barrier performance against oxygen and water vapor, surface hydrophobicity, thermal stability, and resistance to ultraviolet light. Furthermore, we summarize recent advancements in polylactic acid applications for food packaging, highlighting innovations in antioxidant, antimicrobial, and freshness indicator packaging. These developments underscore the significant potential of polylactic acid in the food packaging sector and offer valuable insights for future research directions.

Çolak Y., Belen S.N., Çetin D., Cengiz U., Mert O.

We report the synthesis of s-PSG homopolymers, including a four-armed symmetrical poly(l-diisopropyl glycolide) (4s-PLDIPG) and poly(l-diisobutyl glycolide) (4s-PLDIBG).