“Solvent/non-solvent” treatment as a method for non-covalent immobilization of gelatin on the surface of poly(l-lactic acid) electrospun scaffolds

Sagitha P., Reshmi C.R., Sundaran S.P., Sujith A.

Electrospinning has been considered as a versatile fiber fabrication technique due to its enormous potential to develop polymeric membranes for diverse categories of applications. Modification of bulk and surface properties of electrospun membranes are considered as an effective strategy to design novel synthetic materials with improved properties. Manipulation of surface properties of the membranes by physical and chemical means is an emerging area. The primary emphasis of the review is on a critical evaluation and categorization of post-electrospinning modification techniques in the context of improving membrane performance. It includes both physical (plasma treatment, physical vapour deposition, thermal treatment and ultrasonication) and chemical methods (grafting, oxidation, hydrolysis, cross-linking, aminolysis and acid treatment) of modifications. Additionally, the current progress on click chemistry and radical initiated grafting (ATRP, RAFT and photochemical grafting) techniques for decorating membrane surface are also discussed. A comprehensive evaluation of the relative advantages and disadvantages of different post-modification strategies are provided in detail. The recent advances in applications of modified electrospun membranes for biomedical and water filtration applications are extensively summarized.

Goreninskii S.I., Stankevich K.S., Nemoykina A.L., Bolbasov E.N., Tverdokhlebov S.I., Filimonov V.D.

Fibrous electrospun scaffolds made of poly(L-lactic acid) (PLLA) and poly( $$\upvarepsilon $$ -caprolactone) (PCL) were modified with iodine using ‘solvent/non-solvent’ treatment of the polymer through two-step process. At the first step, the scaffolds were treated with mixture of toluene and ethanol for pre-swelling of the fibre surfaces. Then, treated scaffolds were exposed to iodine vapours to entrap iodine on the polymer surface. Concentration of iodine in obtained materials was measured by means of UV-spectrophotometry. Morphology of the modified scaffolds was characterized by scanning electron microscopy (SEM). Proposed modification had no significant effect on mechanical properties of the scaffolds and their morphologies. Obtained materials demonstrated the E. coli’s antimicrobial activity depending on iodine concentration.

Chen L., Yan C., Zheng Z.

Thorough understanding of how to control cell behaviors including cell adhesion, orientation, migration and differentiation on an artificial surface is critical in materials and life sciences such as advanced biomedical engineering, tissue engineering, and cell-based bioassay. In nature, extracellular matrix (ECM) plays an important role in controlling cell behaviors. It can not only provide the cells with mechanical support but also profoundly affect cell functions such as metabolism, movement and transport process. Functional polymer surface exhibits superior advantages over many other materials for use as artificial ECM owing to its excellent mechanical properties, abundant chemical species and remarkable capability to form various topographical surfaces. In particular, surface chemistry, mechanical properties and topography of these functional polymers are found to be three major parameters for effective control of cell behaviors. This paper comprehensively reviews the fundamental understanding of functional polymer surfaces for controlling cell behaviors. Different fabrication methods to achieve functional polymer surfaces and the parameters for effective control of cell behaviors are discussed. The future prospects and challenges particularly in cell biomedical engineering are also discussed at the end of this review paper.

Aldana A.A., Abraham G.A.

The development of biomimetic highly-porous scaffolds is essential for successful tissue engineering. Electrospun nanofibers are highly versatile platforms for a broad range of applications in different research areas. In the biomedical field, micro/nanoscale fibrous structures have gained great interest for wound dressings, drug delivery systems, soft and hard-tissue engineering scaffolds, enzyme immobilization, among other healthcare applications. In this mini-review, electrospun gelatin-based scaffolds for a variety of tissue engineering applications, such as bone, cartilage, skin, nerve, and ocular and vascular tissue engineering, are reviewed and discussed. Gelatin blends with natural or synthetic polymers exhibit physicochemical, biomechanical, and biocompatibility properties very attractive for scaffolding. Current advances and challenges on this research field are presented.

Ganjalinia A., Akbari S., Solouk A.

Novel aminolyzed Poly (L) Lactic Acid (PLLA) films and electrospun nanofibrous scaffolds were fabricated and characterized as potential substrates for tissue engineering. The second generation polypropylene imine dendrimer (PPI-G2) was used as the aminolysis agent to functionalize the inert surface of PLLA substrates directly without any pre-modification process. The effect of the solvent type, G2 concentration, reaction temperature and time were studied by following weight reduction percentage, FTIR and contact angle measurements due to determined optimum conditions. In addition, the modified scaffolds abbreviated by PLLA/G2 were analyzed using mechanical properties, SEM images and dye assays as host-guest modeling. The results indicate that under the 0.5 (wt.%) G2 concentration, ethanol as the solvent, room temperature and 4 h of treatment, the optimum conditions were obtained. It was shown that the hydrophilic properties of PLLA/G2 were greatly enhanced. Also, pH value analysis revealed that after 4 weeks, the biodegradation of PLLA caused massive immune cells infusion and inflammation in the medium through increasing the acidic rate by secretion the lactic acid, whereas the PLLA/G2 scaffolds greatly reduced and stabilize the acidic rate through aminolysis reaction. Finally, promoted cell adhesion and viability underlined the favorable properties of PLLA/G2 scaffolds as a biodegradable biomaterial for biomedical implants.

Stankevich K.S., Danilenko N.V., Gadirov R.M., Goreninskii S.I., Tverdokhlebov S.I., Filimonov V.D.

A new approach for the immobilization of poly(acrylic) acid (PAA) as a chemically reactive cross-linker on the surface of poly(lactic) acid-based (PLA) biomaterials is described. The proposed technique includes non-covalent attachment of a PAA layer to the surface of PLA-based biomaterial via biomaterial surface treatment with solvent/non-solvent mixture followed by the entrapment of PAA from its solution. Surface morphology and wettability of the obtained PLA-PAA composite materials were investigated by AFM and the sitting drop method respectively. The amount of the carboxyl groups on the composites surface was determined by using the fluorescent compounds (2-(5-aminobenzo[d]oxazol-2-yl)phenol (ABO) and its acyl derivative N-(2-(2-hydroxyphenyl)benzo[d]oxazol-5-yl)acetamide (AcABO)). It was shown that it is possible to obtain PLA-PAA composites with various surface relief and tunable wettability (57°, 62° and 66°). The capacity of the created PAA layer could be varied from 1.5nmol/cm2 to 0.1μmol/cm2 depending on the modification conditions. Additionally, using bovine serum albumin (BSA) it was demonstrated that such composites could be modified with proteins with high binding density (around 0.18nmol/cm2). Obtained fluoro-labeled PLA-PAA materials, as well as PLA-PAA composites themselves, are valuable since they can be used for biodegradable polymer implants tracking in living systems and as drug delivery systems.

Santoro M., Shah S.R., Walker J.L., Mikos A.G.

Poly(lactic acid) (PLA) is a synthetic polyester that has shown extensive utility in tissue engineering. Synthesized either by ring opening polymerization or polycondensation, PLA hydrolytically degrades into lactic acid, a metabolic byproduct, making it suitable for medical applications. Specifically, PLA nanofibers have widened the possible uses of PLA scaffolds for regenerative medicine and drug delivery applications. The use of nanofibrous scaffolds imparts a host of desirable properties, including high surface area, biomimicry of native extracellular matrix architecture, and tuning of mechanical properties, all of which are important facets of designing scaffolds for a particular organ system. Additionally, nanofibrous PLA scaffolds hold great promise as drug delivery carriers, where fabrication parameters and drug-PLA compatibility greatly affect the drug release kinetics. In this review, we present the latest advances in the use of PLA nanofibrous scaffolds for musculoskeletal, nervous, cardiovascular, and cutaneous tissue engineering and offer perspectives on their future use.

Chen W., Chen S., Morsi Y., El-Hamshary H., El-Newhy M., Fan C., Mo X.

Electrospun nanofibers have been used for various biomedical applications. However, electrospinning commonly produces two-dimensional (2D) membranes, which limits the application of nanofibers for the 3D tissue engineering scaffold. In the present study, a porous 3D scaffold (3DS-1) based on electrospun gelatin/PLA nanofibers has been prepared for cartilage tissue regeneration. To further improve the repairing effect of cartilage, a modified scaffold (3DS-2) cross-linked with hyaluronic acid (HA) was also successfully fabricated. The nanofibrous structure, water absorption, and compressive mechanical properties of 3D scaffold were studied. Chondrocytes were cultured on 3D scaffold, and their viability and morphology were examined. 3D scaffolds were also subjected to an in vivo cartilage regeneration study on rabbits using an articular cartilage injury model. The results indicated that 3DS-1 and 3DS-2 exhibited superabsorbent property and excellent cytocompatibility. Both these scaffolds present elastic property in the wet state. An in vivo study showed that 3DS-2 could enhance the repair of cartilage. The present 3D nanofibrous scaffold (3DS-2) would be promising for cartilage tissue engineering application.

Taylor B.L., Limaye A., Yarborough J., Freeman J.W.

Tissue engineering has emerged as a promising solution to tissue regeneration in the case of significant bone loss due to disease or injury. The ability to promote cellular attachment, migration, and differentiation into tissue is dependent on the scaffold's surface properties and composition. Bovine gelatin is a natural polymer commonly used as a scaffolding material for tissue engineering applications. Nonetheless, due to the hydrophilic behavior of gelatin, cross-linking and additives are necessary to maintain the scaffold's structure and overall strength in vivo. In this article, we discuss various processing techniques to determine the optimal electrospinning, cross-linking, sintering, and mineralization parameters necessary to yield a porous, mechanically enhanced scaffold. The scaffolds were evaluated quantitatively using compressive mechanical testing, and qualitatively using scanning electron microscopy (SEM). Mechanical data concluded the use of biocompatible microbial transglutaminase (mTG) as a cross-linking agent, led to increased compressive strength. SEM images confirmed the presence of individual gelatin and polymeric nanofibers woven into one scaffold. Sintering before leaching the scaffold yielded structured pores throughout the three-dimensional scaffold when compared to the scaffolds that were leached prior to sintering. The results presented in this article will provide novel information about processing techniques that can be utilized to develop a hybrid synthetic and biological based biomimetic mineralized scaffold for trabecular bone tissue regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1131-1140, 2017.

Khaliliazar S., Akbari S., Kish M.H.

Poly( l -lactic acid) (PLLA) electrospun fibers and films were modified with the second generation of poly(propylene imine) dendrimer (PPI-G 2 ) by three different approaches, namely, sodium hydroxide hydrolysis, plasma treatment and direct application of PPI-G 2 . For the first and the second approaches, PLLA was modified by sodium hydroxide hydrolysis or plasma treatment to produce carboxylic acid groups. Then, the carboxylic acid groups were activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) and N,N′-dicyclohexyl carbodiimide (DCC) as a hetero bi-functional cross-linker. The cross-linkers promoted the grafting of carboxylic acid groups on the modified PLLA with NH 2 groups of PPI-G 2 . In the third approach, the PPI-G 2 dendrimer was directly used as an aminolysis agent for the functionalization of PLLA in a one step process. FTIR analysis confirmed the presence of NH 2 groups of PPI-G 2 on the modified PLLA samples, resulting from each one of the three modification methods. Studies by SEM shows bead free electrospun fibers. Also, FE-SEM shows nano-cracks on the surface of films after modification. Contact angle, drug release tests, antibacterial effects and the dying results confirmed that these functionalization methods increased hydrophilicity and reactive side-chains of PLLA in the wet chemical process resulted in providing host–guest properties on the PLLA surface for adsorbing various kinds of guest molecules.

Stankevich K.S., Gudima A., Filimonov V.D., Klüter H., Mamontova E.M., Tverdokhlebov S.I., Kzhyshkowska J.

Polylactic acid (PLA) based implants can cause inflammatory complications. Macrophages are key innate immune cells that control inflammation. To provide higher biocompatibility of PLA-based implants with local innate immune cells their surface properties have to be improved. In our study surface modification technique for high-molecular PLA (MW=1,646,600g/mol) based biomaterials was originally developed and successfully applied. Optimal modification conditions were determined. Treatment of PLA films with toluene/ethanol=3/7 mixture for 10min with subsequent exposure in 0.001M brilliant green dye (BGD) solution allows to entrap approximately 10(-9)mol/cm(2) model biomolecules. The modified PLA film surface was characterized by optical microscopy, SERS, FT-IR, UV and TG/DTA/DSC analysis. Tensile strain of modified films was determined as well. The effect of PLA films modified with BGD on the inflammatory reactions of primary human monocyte-derived macrophages was investigated. We developed in vitro test-system by differentiating primary monocyte-derived macrophages on a coating material. Type 1 and type 2 inflammatory cytokines (TNFα, CCL18) secretion and histological biomarkers (CD206, stabilin-1) expression were analyzed by ELISA and confocal microscopy respectively. BGD-modified materials have improved thermal stability and good mechanical properties. However, BGD modifications induced additional donor-specific inflammatory reactions and suppressed tolerogenic phenotype of macrophages. Therefore, our test-system successfully demonstrated specific immunomodulatory effects of original and modified PLA-based biomaterials, and can be further applied for the examination of improved coatings for implants and identification of patient-specific reactions to implants.

Torricelli P., Gioffrè M., Fiorani A., Panzavolta S., Gualandi C., Fini M., Focarete M.L., Bigi A.

Bio-synthetic scaffolds of interspersed poly(l-lactic acid) (PLLA) and gelatin (GEL) fibers are fabricated by co-electrospinning. Tailored PLLA/GEL compositions are obtained and GEL crosslinking with genipin provides for the maintenance of good fiber morphology. Scaffold tensile mechanical properties are intermediate between those of pure PLLA and GEL and vary as a function of PLLA content. Primary human chondrocytes grown on the scaffolds exhibit good proliferation and increased values of the differentiation parameters, especially for intermediate PLLA/GEL compositions. Mineralization tests enable the deposition of a uniform layer of poorly crystalline apatite onto the scaffolds, suggesting potential applications involving cartilage as well as cartilage-bone interface tissue engineering.

Binan L., Tendey C., De Crescenzo G., El Ayoubi R., Ajji A., Jolicoeur M.

Neural stem cells (NSCs) provide promising therapeutic potential for cell replacement therapy in spinal cord injury (SCI). However, high increases of cell viability and poor control of cell differentiation remain major obstacles. In this study, we have developed a non-woven material made of co-electrospun fibers of poly L-lactic acid and gelatin with a degradation rate and mechanical properties similar to peripheral nerve tissue and investigated their effect on cell survival and differentiation into motor neuronal lineages through the controlled release of retinoic acid (RA) and purmorphamine. Engineered Neural Stem-Like Cells (NSLCs) seeded on these fibers, with and without the instructive cues, differentiated into β-III-tubulin, HB-9, Islet-1, and choactase-positive motor neurons by immunostaining, in response to the release of the biomolecules. In addition, the bioactive material not only enhanced the differentiation into motor neuronal lineages but also promoted neurite outgrowth. This study elucidated that a combination of electrospun fiber scaffolds, neural stem cells, and controlled delivery of instructive cues could lead to the development of a better strategy for peripheral nerve injury repair.

Lavenus S., Berreur M., Trichet V., Pilet P., Louarn G., Layrolle P.

Soliman S., Sant S., Nichol J.W., Khabiry M., Traversa E., Khademhosseini A.

Porosity has been shown to be a key determinant of the success of tissue engineered scaffolds. A high degree of porosity and an appropriate pore size are necessary to provide adequate space for cell spreading and migration as well as to allow for proper exchange of nutrients and waste between the scaffold and the surrounding environment. Electrospun scaffolds offer an attractive approach for mimicking the natural extracellular matrix (ECM) for tissue engineering applications. The efficacy of electrospinning is likely to depend on the interaction between cells and the geometric features and physicochemical composition of the scaffold. A major problem in electrospinning is the tendency of fibers to accumulate densely, resulting in poor porosity and small pore size. The porosity and pore sizes in the electrospun scaffolds are mainly dependent on the fiber diameter and their packing density. Here we report a method of modulating porosity in three dimensional (3D) scaffolds by simultaneously tuning the fiber diameter and the fiber packing density. Nonwoven poly(ε-caprolactone) mats were formed by electrospinning under various conditions to generate sparse or highly dense micro- and nanofibrous scaffolds and characterized for their physicochemical and biological properties. We found that microfibers with low packing density resulted in improved cell viability, proliferation and infiltration compared to tightly packed scaffolds.

Stoykov I.I., Antipin I.S., Burilov V.A., Kurbangalieva A.R., Rostovsky N.V., Pankova A.S., Balova I.A., Remizov Y.O., Pevzner L.M., Petrov M.L., Vasily A.V., Averin A.D., Beletskaya I.P., Nenaydenko V.G., Beloglazkina E.K., et. al.

An overview of the main scientific achievements of Russian universities in the field of organic chemistry for the period 2018–2023 is presented.

Stoikov I.I., Antipin I.S., Burilov V.A., Kurbangalieva A.R., Rostovskii N.V., Pankova A.S., Balova I.A., Remizov Y.O., Pevzner L.M., Petrov M.L., Vasilyev A.V., Averin A.D., Beletskaya I.P., Nenajdenko V.G., Beloglazkina E.K., et. al.

An overview of the main scientific achievements of Russian universities in the field of organic chemistry over the period 2018–2023 is presented.

Birdibekova A.V., Starostina E.A., Kuryanova A.S., Aksenova N.A., Timashev P.S., Akopova T.A., Demina T.S.

The surface modification of polycaprolactone and polycaprolactone/polylactide mixed films was carried out by preliminary surface activation in NaOH. Subsequent layer-by-layer deposition of coatings based on polyelectrolyte complexes of the oppositely charged polysaccharides: chitosan and hyaluronic acid, was carried out. The effect of surface activation was studied using contact angle measurements, surface analysis and gravimetric data. The characterization of the polyelectrolyte complex coatings using gravimetric analysis, goniometric and micrometer measurements, scanning electron, optical and fluorescence microscopy, and FTIR-ATR spectroscopy confirmed the formation of a uniform coating with a thickness of about 30 μm, which is not prone to peeling from the substrate.

Popkov A., Kononovich N., Dubinenko G., Gorbach E., Shastov A., Tverdokhlebov S., Popkov D.

Previously, 3D-printed bone grafts made of titanium alloy with bioactive coating has shown great potential for the restoration of bone defects. Implanted into a medullary canal titanium graft with cellular structure demonstrated stimulation of the reparative osteogenesis and successful osseointegration of the graft into a single bone-implant block. The purpose of this study was to investigate osseointegration of a 3D-printed degradable polymeric implant with cellular structure as preclinical testing of a new technique for bone defect restoration. During an experimental study in sheep, a 20 mm-long segmental tibial defect was filled with an original cylindrical implant with cellular structure made of polycaprolactone coated with hydroxyapatite. X-ray radiographs demonstrated reparative bone regeneration from the periosteum lying on the periphery of cylindrical implant to its center in a week after the surgery. Cellular structure of the implant was fully filled with newly-formed bone tissue on the 4th week after the surgery. The bone tissue regeneration from the proximal and distal bone fragments was evident on 3rd week. This provides insight into the use of bioactive degradable implants for the restoration of segmental bone defects. Degradable implant with bioactive coating implanted into a long bone segmental defect provides stimulation of reparative osteogenesis and osseointegration into the single implant-bone block.

Petrova V.A., Gofman I.V., Dubashynskaya N.V., Golovkin A.S., Mishanin A.I., Ivan’kova E.M., Romanov D.P., Khripunov A.K., Vlasova E.N., Migunova A.V., Baranchikov A.E., Ivanov V.K., Yakimansky A.V., Skorik Y.A.

In this work, new composite films were prepared by incorporating the disintegrated bacterial cellulose (BCd) nanofibers and cerium oxide nanoparticles into chitosan (CS) matrices. The influence of the amount of nanofillers on the structure and properties of the polymer composites and the specific features of the intermolecular interactions in the materials were determined. An increase in film stiffness was observed as a result of reinforcing the CS matrix with BCd nanofibers: the Young’s modulus increased from 4.55 to 6.3 GPa with the introduction of 5% BCd. A further increase in Young’s modulus of 6.7 GPa and a significant increase in film strength (22% increase in yield stress compared to the CS film) were observed when the BCd concentration was increased to 20%. The amount of nanosized ceria affected the structure of the composite, followed by a change in the hydrophilic properties and texture of the composite films. Increasing the amount of nanoceria to 8% significantly improved the biocompatibility of the films and their adhesion to the culture of mesenchymal stem cells. The obtained nanocomposite films combine a number of favorable properties (good mechanical strength in dry and swollen states, improved biocompatibility in relation to the culture of mesenchymal stem cells), which allows us to recommend them for use as a matrix material for the culture of mesenchymal stem cells and wound dressings.

Petrova V.A., Dubashynskaya N.V., Gofman I.V., Golovkin A.S., Mishanin A.I., Aquino A.D., Mukhametdinova D.V., Nikolaeva A.L., Ivan'kova E.M., Baranchikov A.E., Yakimansky A.V., Ivanov V.K., Skorik Y.A.

Polymeric nanocomposite materials have great potential in the development of tissue-engineered scaffolds because they affect the structure and properties of polymeric materials and regulate cell proliferation and differentiation. In this work, cerium oxide nanoparticles (CeONPs) were incorporated into a chitosan (CS) film to improve the proliferation of multipotent mesenchymal stem cells (MSCs). The citrate-stabilized CeONPs with a negative ζ-potential (−25.0 mV) were precoated with CS to obtain positively charged particles (+20.3 mV) and to prevent their aggregation in the composite solution. The composite CS–CeONP films were prepared in the salt and basic forms using a dry-cast process. The films obtained in both forms were characterized by a uniform distribution of CeONPs. The incorporation of CeONPs into the salt form of CS increased the stiffness of the CS–CeONP film, while the subsequent conversion of the film to the basic form provided a two- to threefold decrease in both the Young's modulus and the yield point. The redox activity (Ce4+ ⇌ Ce3+) of cerium oxide in the CS–CeONP film was confirmed by thermal oxidative degradation. In vitro culture of MSCs showed that the CS–CeONP film has good biocompatibility, and in vivo experiments demonstrated its substantial regenerative potential.

Demina T.S., Piskarev M.S., Birdibekova A.V., Veryasova N.N., Shpichka A.I., Kosheleva N.V., Gatin A.K., Skryleva E.A., Istranova E.V., Gilman A.B., Akopova T.A., Timashev P.S.

Enhancement of cell adhesion and growth on surface of the biodegradable materials is one of the important tasks in development of materials for regenerative medicine. This work focuses on comparison of various methods of collagen coating deposition onto polylactide films, aiming to increase their biocompatibility with human mesenchymal stromal cells. The collagen deposition was realized using either preliminary plasma treatment of the polylactide films or pre-swelling in solvent mixture. These techniques were compared in terms of the effect on the surface’s chemical structure, morphology, hydrophilicity and ability to support adhesion and growth of human mesenchymal stromal cells.

Surendren A., Cheekuramelli N.S., Magisetty R.P.

Tissue engineering is an emerging technology in developing a three-dimensional biological alternative for functional human tissue or organs from mammalian cells. However, these cells are anchorage-dependent and distinct environment-dependent, which requires proper culture medium such as scaffolds to support the cell proliferation and act as a prototype for the growth. Biomaterial scaffold is an ideal substrate with its comparable properties with natural extracellular matrix for tissue engineering. The key characteristic of biomaterials is to interact and coexist in the presence of physiological systems such as blood, immune cells, and interstitial fluids with the minimum amount of immune reaction from the recipient. Natural polymers, synthetic biodegradable, and nonbiodegradable polymers are the main types of biomaterials for scaffolding applications. This chapter explains the property evaluation and application of biodegradable polymer blends for tissue engineering.

Biazar E., Kamalvand M., Avani F.

Nanofibrous biomaterials, because of their structural similarity to the extracellular matrix, can be employed as a scaffold in tissue engineering. The use of biopolymers to nanofibers fabrication a...

Liu S., Qin S., He M., Zhou D., Qin Q., Wang H.

Biodegradable poly(lactic acid) (PLA) presents suitable physicochemical properties and biocompatibility for biomedical engineering. However, PLA has some drawbacks, such as low cell adhesion, biological inertness, low degradation rate, and acid degradation by-products. In this review, recent progress on strategies to address these problems is summarized, including novel fabrication techniques, high-performance PLA composites, and their applications for tissue engineering and drug delivery. The scaffolds, especially for bone regeneration, blood vessels, organs, and skin regeneration are evaluated, in terms of in vivo and in vitro biocompatibility and biodegradability. The enhanced mechanical, thermal, and rheological properties of PLA biocomposites are analyzed in detail. PLA biocomposites for drug encapsulation, sustained release, and tumor-targeting are also reviewed. Furthermore, the challenges and future perspectives on PLA-based biocomposites are discussed.

Kost B., Svyntkivska M., Brzeziński M., Makowski T., Piorkowska E., Rajkowska K., Kunicka-Styczyńska A., Biela T.

• Linear and star-shaped polylactides were used for the preparation of nonwovens. • The electrospinning was employed to obtain Quercetin (Q)-loaded nonwovens. • Nonwovens loaded with Q exhibited excellent antibacterial abilities. • All obtained fibres reduced the coloring properties of quercetin. Microbial infections lead to elevated inflammatory responses, which usually result in prolonged and incomplete wound healing. Therefore, there is an increasing demand for biodegradable fibres that are effective against a different range of microorganisms, especially those with antibiotic resistance. Herein, quercetin-(Q)-loaded polylactide-based fibres were developed using the electrospinning technique. Since Q exhibits low chemical stability, we used star-shaped polylactides (PLAs) with a β-CD core to host Q by inclusion complexation. To enhance the stability of the fibres and additionally entrap the Q between polymeric chains, we adapted supramolecular cross-linking by the stereocomplexation of PLAs with opposite configurations. As a control, we prepared an additional formulation of star-shaped/commercial PLA/Q for the preparation of nonwovens in which the β-CD moiety was not present. All developed fibres were smooth and continuous, with an average diameter of 37 μm. Although nonwovens did not possess diffusible activity, good antibacterial effects against Staphylococcus aureus ( S. aureus ), Escherichia coli ( E.coli ) and Klebsiella pneumoniae ( K. pneumoniae ) were observed. All these features validate the proposed approach, in which different supramolecular interactions were used to modify the properties of PLA-based fibres and, most importantly, show their great potential usefulness against microbial infections.

Lipovka A., Rodriguez R., Bolbasov E., Maryin P., Tverdokhlebov S., Sheremet E.

The polymer scaffolds surfaces are inherently hydrophobic what limits its performance as implants and compatibility with human tissue essential for such applications as tissue engineering, nerve regeneration, drug delivery, etc. The plasma treatment was demonstrated to change the wetting properties of scaffolds making them hydrophilic. However, that is not a lasting effect. In this work, we aim at addressing this problem with systematic time-stability investigation of scaffolds functionalized with graphene oxide (GO) layers. To this end, we used several polymers including polycaprolactone (PCL), poly-L-lactic acid (PLLA), l -lactide-co-glycolide copolymer (PLGA) and l -lactide-co-caprolactone copolymer (PLC) functionalized with GO, evaluating also control samples without any treatment and treated by plasma. Our results demonstrate that the GO coating provides a successful and stable hydrophilic functionality to all polymer scaffolds here investigated. Contrary to plasma treatment used as a reference for the surface-wettability provider, only the GO effects remain stable for extended periods of up to 30 days. This work contributes to the robust application of graphene-functionalized polymer scaffolds with long lifetime hydrophilicity.