Imparting superhydrophobicity to biodegradable poly(lactide-co-glycolide) electrospun meshes

Modulating Lysosomal pH through Innovative Multimerized Succinic Acid-Based Nucleolipid Derivatives

The multimerization of active compounds has emerged as a successful approach, mainly to address the multivalency of numerous biological targets. Regarding the pharmaceutical prospect, carrying several active ingredient units on the same synthetic scaffold was a practical approach to enhance drug delivery or biological activity with a lower global concentration. Various examples have highlighted better in vivo stability and therapeutic efficiency through sustained action over monomeric molecules. The synthesis strategy aims to covalently connect biologically active monomers to a central core using simple and efficient reaction steps. Despite extensive studies reporting carbohydrate or even peptide multimerization developed for therapeutic activities, very few are concerned with nucleic acid derivatives. In the context of our efforts to build non-viral nucleolipid (NL)-based nanocarriers to restore lysosomal acidification defects, we report here a straightforward synthesis of tetrameric NLs, designed as prodrugs that are able to release no more than one but four biocompatible succinic acid units. The use of oil-in-water nanoemulsion-type vehicles allowed the development of lipid nanosystems crossing the membranes of human neuroblastoma cells. Biological evaluations have proved the effective release of the acid within the lysosome of a genetic and cellular model of Parkinson's disease through the recovery of an optimal lysosomal pH associated with a remarkably fourfold lower concentration of active ingredients than with the corresponding monomers. Overall, these results suggest the feasibility, the therapeutic opportunity, and the better tolerance of multimeric compounds compared to only monomer molecules.

Doxorubicin-Loaded Polymeric Meshes Prevent Local Recurrence after Sarcoma Resection While Avoiding Cardiotoxicity

Surgery is the only potentially curative treatment for localized soft-tissue sarcomas. However, for sarcomas arising in the retroperitoneum, locoregional recurrence rates are 35% to 59% despite resection. Doxorubicin (DOX) is the standard first-line systemic chemotherapy for advanced soft-tissue sarcoma, yet its intravenous administration yields limited clinical efficacy and results in dose-limiting cardiotoxicity. We report the fabrication and optimization of a novel electrospun poly(caprolactone) (PCL) surgical mesh coated with layers of a hydrophobic polymer (poly(glycerol monostearate-co-caprolactone), PGC-C18), which delivers DOX directly to the operative bed following sarcoma resection. In xenograft models of liposarcoma and chondrosarcoma, DOX-loaded meshes (DoM) increased overall survival 4-fold compared with systemically administered DOX and prevented local recurrence in all but one animal. Importantly, mice implanted with DoMs exhibited preserved cardiac function, whereas mice receiving an equivalent dose systemically displayed a 23% decrease from baseline in both cardiac output and ejection fraction 20 days after administration. Collectively, this work demonstrates a feasible therapeutic approach to simultaneously prevent post-surgical tumor recurrence and minimize cardiotoxicity in soft-tissue sarcoma.

SIGNIFICANCE

A proof-of-principle study in animal models shows that a novel local drug delivery approach can prevent tumor recurrence as well as drug-related adverse events following surgical resection of soft-tissue sarcomas.

Slippery Antifouling Polymer Coatings Fabricated Entirely from Biodegradable and Biocompatible Components

We report the design of slippery liquid-infused porous surfaces (SLIPS) fabricated from building blocks that are biodegradable, edible, or generally regarded to be biocompatible. Our approach involves infusion of lubricating oils, including food oils, into nanofiber-based mats fabricated by electrospinning or blow spinning of poly(ε-caprolactone), a hydrophobic biodegradable polymer used widely in medical implants and drug delivery devices. This approach leads to durable and biodegradable SLIPS that prevent fouling by liquids and other materials, including microbial pathogens, on objects of arbitrary shape, size, and topography. This degradable polymer approach also provides practical means to design "controlled-release" SLIPS that release molecular cargo at rates that can be manipulated by the properties of the infused oils (e.g., viscosity or chemical structure). Together, our results provide new designs and introduce useful properties and behaviors to antifouling SLIPS, address important issues related to biocompatibility and environmental persistence, and thus advance new potential applications, including the use of slippery materials for food packaging, industrial and marine coatings, and biomedical implants.

Basic Principles of Electrospinning, Mechanisms, Nanofibre Production, and Anticancer Drug Delivery

Electrospun nanofibres are environmentally friendly compounds, when compared with other approaches of manufacturing nanofibres. This study reviews an easy and simple approach process of producing nanofibres called electrospinning. This review further gives an overview and successful methodical approaches to obtain electrospun (ES) nanofibres appropriate for anticancer drug delivery. The properties and characterization of electrospun nanofibres were reported to confirm successful nanofibre production. The application of characterized ES nanofibres is to deliver the anticancer drug to the right target in the human body. The implication of this study is the application of some of the merits of ES nanofibres (biocompatability, biodegradability, low-cost production, small pore size, and ability to transport anticancer drug to the target cell or organ) to overcome the challenges experienced in the use of anticancer chemotherapeutic agents.

Self-standing films of octadecylaminated-TEMPO-oxidized cellulose nanofibrils with antifingerprint properties

Self-standing films of cellulose nanofibril derivatives were prepared via oxidation by the 2,2,6,6-tetramethyl-1-piperidinyloxy radical and amidation with octadecylamine (ODA). The transparency and rigidity of the films decreased and their flexibility increased as the amide/carboxyl ratio increased. The introduction of the ODA also resulted in rising contact angles of water (from 43.5° to 117°) and oleic acid (from 22.5° to 57.1°). Furthermore, the films exhibited unique oil repellency: a drop of hexadecane slipped without tailing on the surface modified by ODA. This phenomenon was observed after moderate modification (water contact angle: 95-114°) and was absent for the films with the lowest and highest extents of modification. Then, the antifingerprint property of the films was examined by means of the powder test, and a reduction in fingerprints on the films was demonstrated. These results suggest the usefulness of developing transparent, self-standing oil-repellent films without perfluorinated compounds for antifingerprint and other antifouling applications.

Study on the biodegradability of modified starch/polylactic acid (PLA) composite materials

In this work, polylactic acid/thermoplastic acetylated starch (PLA/TPAS) composites were prepared using PLA as a matrix material and TPAS as a modifier. TPAS is based on acetylated starch, which is plasticized using glycerin. Analysis of the mechanical, thermal, and dynamic mechanical properties, and morphological structures of the PLA/TPAS composites shows that with an increase in the TPAS content, the toughness of the PLA/TPAS composites significantly improves. When the amount of TPAS added is 40% by weight, the elongation at break is increased 4 times. At the same time, the addition of TPAS has little effect on the thermal stability of the composites. Differential scanning calorimetry (DSC), dynamic mechanical analysis and scanning electron microscopy (SEM) analysis results show that PLA is incompatible with TPAS. The addition of TPAS promotes the crystallization of PLA, resulting in a decrease in the thermal stability but limits the degradation behavior during the processing of the material, which has little effect on the performance of the material. High temperature and high humidity soil degradation and ultraviolet radiation aging experiments on PLA/TPAS composites show that the PLA/TPAS composites have good biodegradability. In soil burial degradation experiments, the degradation rate of the pure PLA material is slow, and its final mass retention rate is high. The PLA/TPAS composites degrade fast. In ultraviolet radiation aging experiments, the tensile strength of the PLA/TPAS composites was improved to a certain extent after exposure to ultraviolet radiation. With an increase in the ultraviolet irradiation time, the tensile properties of the PLA/TPAS composites gradually decreased.

In this work, polylactic acid/thermoplastic acetylated starch (PLA/TPAS) composites were prepared using PLA as a matrix material and TPAS as a modifier.

Meniscus-shaped cell-free polyglycolic acid scaffold for meniscal repair in a sheep model

Since loss of meniscus is correlated with an increasing risk for osteoarthritis, meniscal scaffolds are proposed as new strategies. Development of a suitable scaffold has to take into account differing meniscus thickness, exposure to compressive and tensile forces combined with high porosity and biocompatibility of the material. After physical testing of three flat scaffolds composed of different modified polyglycolic acid (PGA) fibers, a three-dimensional meniscus-shaped PGA-hyaluronan implant was generated. Micro-computed tomography showed 90% porosity in the outer area with 50% in the inner area of the implant. Biocompatibility and expression of meniscus typical cartilaginous genes were shown for human meniscus cells cultivated in the implant with 10% human serum or 5% platelet-rich plasma for 14 days in vitro. The proof-of-concept study in sheep demonstrated proteoglycan- and collagen type I-rich repair tissue formation in partial meniscectomy combined with a meniscus-shaped PGA-hyaluronan implant after 6 months. In contrast, the control showed nearly no repair tissue formation. Thus, meniscus-shaped PGA-hyaluronan implants might be a suitable therapeutic approach to support repair tissue formation in partial meniscectomy.

Photocrosslinkable Nanofibrous Asymmetric Membrane Designed for Wound Dressing

Recently, the biomedical scientists who are working in the skin regeneration area have proposed asymmetric membranes as ideal wound dressings, since they are able to reproduce both layers of skin and improve the healing process as well as make it less painful. Herein, an electrospinning technique was used to produce new asymmetric membranes. The protective layer was composed of a blending solution between polycaprolactone and polylactic acid, whereas the underlying layer was comprised of methacrylated gelatin and chitosan. The chemical/physical properties, the in vitro hemo- and biocompatibility of the nanofibrous membranes were evaluated. The results obtained reveal that the produced membranes exhibited a wettability able to provide a moist environment at wound site. Moreover, the membranes' hemocompatibility and fibroblast cell adhesion, spreading and proliferation at the surface of the membranes were also noticed in the in vitro assays. Such results highlight the suitability of these asymmetric membranes for wound dressing applications.

Harnessing Lysosomal pH through PLGA Nanoemulsion as a Treatment of Lysosomal-Related Neurodegenerative Diseases

Most neurodegenerative disorders are characterized by deposits of misfolded proteins and neuronal degeneration in specific brain regions. Growing evidence indicates that lysosomal impairment plays a primary pathogenic role in these diseases, in particular, the occurrence of increased lysosomal pH. Thus, therapeutic development aiming at restoring lysosomal function represents a novel, precise, and promising strategy for the treatment of these pathologies. Herein we demonstrate that acidic oil-in-water nanoemulsions loaded with poly(dl-lactide- co-glycolide) (PLGA) are able to rescue impaired lysosomal pH in genetic cellular models of Parkinson's disease. For in vivo assays, nanoemulsions were labeled with an original synthetic hydrophobic far red-emitting dye to allow fluorescence monitoring. Following stereotaxic injection in the mouse brain, widespread diffusion of the nanocarrier was observed, up to 500 μm from the injection site, as well as internalization into the lysosomal compartment in brain cells. Finally, promising preliminary assays of systemic administration demonstrate that a fraction of the formulation crosses the blood brain barrier, penetrates the brain parenchyma, is internalized by cells, and colocalizes with lysosomal markers. Overall, these results suggest the feasibility and the therapeutic potential of this new nanoformulation as an effective drug delivery tool to the brain, with the potential to rescue pathological lysosomal deficits.

Polymer sutures for simultaneous wound healing and drug delivery - A review

Drug delivery using suitable polymeric devices has gathered momentum in the recent years due to their remarkable properties. The versatility of polymeric materials makes them reliable candidates for site targeted drug release. Among them biodegradable sutures has received considerable attention because they offer great promises in the realm of drug delivery. Sutures have been found to be an effective strategy for the delivery of antibacterial agents or anti-inflammatory drugs to the surgical site. Recent developments yielded sutures with improved mechanical properties, but designing sutures with all the desirable properties is still under investigation. This review is an attempt to analyze the recent developments pertaining to biologically active sutures emphasizing their potential as drug delivery vehicle.

Fluorine-Enriched Melt-Blown Fibers from Polymer Blends of Poly(butylene terephthalate) and a Fluorinated Multiblock Copolyester

Melt-blown fibers (dav ∼1 μm) were produced from blends of poly(butylene terephthalate) (PBT) and a partially fluorinated random multiblock copolyester (PFCE) leading to enhanced hydrophobicity and even superhydrophobicity (static water contact angle = 157 ± 3°) of the associated fiber mats. XPS measurements demonstrated quantitatively that the surface fluorine content increased systematically with the bulk loading of PFCE, rising to nearly 20 atom %, which corresponds to 41 wt % PFCE at a bulk loading of 10 wt %. The PBT/PFCE fibers exhibit greater fluorine surface segregation than either melt-blown PBT/poly(ethylene-co-chlorotrifluoroethylene) (PBT/PECTFE) fibers or electrospun fibers obtained from blends of poly(styrene) and fluoroalkyl end-capped polystyrene (PS/PSCF). Dynamic contact angle measurements further demonstrated decreased surface adhesion energy of the melt-blown PBT/PFCE fiber mats due to the blooming of PFCE to the surface.

Antitumor Activity of Doxorubicin-Loaded Carbon Nanotubes Incorporated Poly(Lactic-Co-Glycolic Acid) Electrospun Composite Nanofibers

The drug-loaded composite electrospun nanofiber has attracted more attention in biomedical field, especially in cancer therapy. In this study, a composite nanofiber was fabricated by electrospinning for cancer treatment. Firstly, the carbon nanotubes (CNTs) were selected as carriers to load the anticancer drug-doxorubicin (DOX) hydrochloride. Secondly, the DOX-loaded CNTs (DOX@CNTs) were incorporated into the poly(lactic-co-glycolic acid) (PLGA) nanofibers via electrospinning. Finally, a new drug-loaded nanofibrous scaffold (PLGA/DOX@CNTs) was formed. The properties of the prepared composite nanofibrous mats were characterized by various techniques. The release profiles of the different DOX-loaded nanofibers were measured, and the in vitro antitumor efficacy against HeLa cells was also evaluated. The results showed that DOX-loaded CNTs can be readily incorporated into the nanofibers with relatively uniform distribution within the nanofibers. More importantly, the drug from the composite nanofibers can be released in a sustained and prolonged manner, and thereby, a significant antitumor efficacy in vitro is obtained. Thus, the prepared composite nanofibrous mats are a promising alternative for cancer treatment.

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial applications. Here we describe how electrospinning or electrospraying a polymer mixture containing a biodegradable, biocompatible aliphatic polyester (e.g., polycaprolactone and poly(lactide-co-glycolide)), as the major component, doped with a hydrophobic copolymer composed of the polyester and a stearate-modified poly(glycerol carbonate) affords a superhydrophobic biomaterial. The fabrication techniques of electrospinning or electrospraying provide the enhanced surface roughness and porosity on and within the fibers or the particles, respectively. The use of a low surface energy copolymer dopant that blends with the polyester and can be stably electrospun or electrosprayed affords these superhydrophobic materials. Important parameters such as fiber size, copolymer dopant composition and/or concentration, and their effects on wettability are discussed. This combination of polymer chemistry and process engineering affords a versatile approach to develop application-specific materials using scalable techniques, which are likely generalizable to a wider class of polymers for a variety of applications.

Recent advances in glycerol polymers: chemistry and biomedical applications

Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, the underlying chemistry of glycerol that provides access to a range of monomers for subsequent polymerizations is described. Then, the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth are reviewed. Next, several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity are described. Fourth, the growing market opportunity for the use of polymers in medicine is described. Finally, the findings are concluded and summarized, as well as the potential opportunities for continued research efforts are discussed.