Star poly(ε-caprolactone)-based electrospun fibers as biocompatible scaffold for doxorubicin with prolonged drug release activity

Poly(ε-caprolactone)/bioactive glass composite electrospun fibers for tissue engineering applications

In this work, composite electrospun fibers containing innovative bioactive glass nanoparticles were produced and characterized. Poly(ε-caprolactone), benign solvents, and sol-gel B- and Cu-doped bioactive glass powders were used to fabricate fibrous scaffolds. The retention of bioactive glass nanoparticles in the polymer matrix, the electrospinnability of this novel solution and the obtained electrospun composites were extensively characterized. As a result, composite electrospun fibers characterized by biocompatibility, bioactivity, and exhibiting overall properties adequate for both hard and soft tissue engineering applications, have been produced. The addition of these bioactive glass nanoparticles was, indeed, able to impart bioactive properties to the fibers. Cell culture studies show promising results, demonstrating proliferation and growth of cells on the composite fibers. Wettability, degradation rate, and mechanical performance were also tested and are in line with previous results.

High dose, dual-release polymeric films for extended surgical bed paclitaxel delivery

While surgery represents a major therapy for most solid organ cancers, local recurrence is clinically problematic for cancers such as sarcoma for which adjuvant radiotherapy and systemic chemotherapy provide minimal local control or survival benefit and are dose-limited due to off-target side effects. We describe an implantable, biodegradable poly(1,2-glycerol carbonate) and poly(caprolactone) film with entrapped and covalently-bound paclitaxel enabling safe, controlled, and extended local delivery of paclitaxel achieving concentrations 10,000× tissue levels compared to systemic administration. Films containing entrapped and covalently-bound paclitaxel implanted in the tumor bed, immediately after resection of human cell line-derived chondrosarcoma and patient-derived xenograft liposarcoma and leiomyosarcoma in mice, improve median 90- or 200-day recurrence-free and overall survival compared to control mice. Furthermore, mice in the experimental film arm show no film-related morbidity. Continuous, extended, high-dose paclitaxel delivery via this unique polymer platform safely improves outcomes in three different sarcoma models and provides a rationale for future incorporation into human trials.

Enzymatic Degradation of Polylactic Acid Fibers Supported on a Hydrogel for Sustained Release of Lactate

The incorporation of exogenous lactate into cardiac tissues is a regenerative strategy that is rapidly gaining attention. In this work, two polymeric platforms were designed to achieve a sustained release of lactate, combining immediate and prolonged release profiles. Both platforms contained electrospun poly(lactic acid) (PLA) fibers and an alginate (Alg) hydrogel. In the first platform, named L/K(x)/Alg-PLA, lactate and proteinase K (x mg of enzyme per 1 g of PLA) were directly loaded into the Alg hydrogel, into which PLA fibers were assembled. In the second platform, L/Alg-K(x)/PLA, fibers were produced by electrospinning a proteinase K:PLA solution and, subsequently, assembled within the lactate-loaded hydrogel. After characterizing the chemical, morphological, and mechanical properties of the systems, as well as their cytotoxicity, the release profiles of the two platforms were determined considering different amounts of proteinase K (x = 5.2, 26, and 52 mg of proteinase K per 1 g of PLA), which is known to exhibit a broad cleavage activity. The profiles obtained using L/Alg-K(x)/PLA platforms with x = 26 and 52 were the closest to the criteria that must be met for cardiac tissue regeneration. Finally, the amount of lactate directly loaded in the Alg hydrogel for immediate release and the amount of protein in the electrospinning solution were adapted to achieve a constant lactate release of around 6 mM per day over 1 or 2 weeks. In the optimized bioplatform, in which 6 mM lactate was loaded in the hydrogel, the amount of fibers was increased by a factor of ×3, the amount of enzyme was adjusted to 40 mg per 1 g of PLA, and a daily lactate release of 5.9 ± 2.7 mM over a period of 11 days was achieved. Accordingly, the engineered device fully satisfied the characteristics and requirements for heart tissue regeneration.

Development of Boron-Containing PVA-Based Cryogels with Controllable Boron Releasing Rate and Altered Influence on Osteoblasts

Cryogel formation is an effective approach to produce porous scaffolds for tissue engineering. In this study, cryogelation was performed to produce boron-containing scaffolds for bone tissue engineering. A combination of the synthetic polymer, poly(vinyl alcohol) (PVA), and the natural polymers, chitosan and starch, was used to formulate the cryogels. Boron was used with a dual purpose: as an additive to alter gelation properties, and to exploit its bioactive effect since boron has been found to be involved in several metabolic pathways, including the promotion of bone growth. This project designs a fabrication protocol enabling the competition of both physical and chemical cross-linking reactions in the cryogels using different molecular weight PVA and borax content (boron source). Using a high ratio of high-molecular-weight PVA resulted in the cryogels exhibiting greater mechanical properties, a lower degradation rate (0.6–1.7% vs. 18–20%) and a higher borax content release (4.98 vs. 1.85, 1.08 nanomole) in contrast to their counterparts with low-molecular-weight PVA. The bioactive impacts of the released borax on cellular behaviour were investigated using MG63 cells seeded into the cryogel scaffolds. It was revealed that the borax-containing scaffolds and their extracts induced MG63 cell migration and the formation of nodule-like aggregates, whilst cryogel scaffolds without borax did not. Moreover, the degradation products of the scaffolds were analysed through the quantification of boron release by the curcumin assay. The impact on cellular response in a scratch assay confirmed that borax released by the scaffold into media (~0.4 mg/mL) induced bone cell migration, proliferation and aggregation. This study demonstrated that boron-containing three-dimensional PVA/starch–chitosan scaffolds can potentially be used within bone tissue engineering applications.

Advancements and Utilizations of Scaffolds in Tissue Engineering and Drug Delivery

The drug development process requires a thorough understanding of the scaffold and its three-dimensional structure. Scaffolding is a technique for tissue engineering and the formation of contemporary functioning tissues. Tissue engineering is sometimes referred to as regenerative medicine. They also ensure that drugs are delivered with precision. Information regarding scaffolding techniques, scaffolding kinds, and other relevant facts, such as 3D nanostructuring, are discussed in depth in this literature. They are specific and demonstrate localized action for a specific reason. Scaffold's acquisition nature and flexibility make it a new drug delivery technology with good availability and structural parameter management.

Nanofibrous materials affect the reaction of cytotoxicity assays

Nanofibrous materials are widely investigated as a replacement for the extracellular matrix, the 3D foundation for cells in all tissues. However, as with every medical material, nanofibers too must pass all safety evaluations like in vitro cytotoxicity assays or in vivo animal tests. Our literature research showed that differences in results of widely used cytotoxicity assays applied to evaluate nanofibrous materials are poorly understood. To better explore this issue, we prepared three nanofibrous materials with similar physical properties made of poly-L-lactic acid, polyurethane, and polycaprolactone. We tested five metabolic cytotoxicity assays (MTT, XTT, CCK-8, alamarBlue, PrestoBlue) and obtained different viability results for the same nanofibrous materials. Further, the study revealed that nanofibrous materials affect the reaction of cytotoxicity assays. Considering the results of both described experiments, it is evident that validating all available cytotoxicity assays for nanofibrous materials and possibly other highly porous materials should be carefully planned and verified using an additional analytical tool, like scanning electron microscopy or, more preferably, confocal microscopy.

Nature-Derived and Synthetic Additives to poly(ɛ-Caprolactone) Nanofibrous Systems for Biomedicine; an Updated Overview

As a low cost, biocompatible, and bioresorbable synthetic polymer, poly (ɛ-caprolactone) (PCL) is widely used for different biomedical applications including drug delivery, wound dressing, and tissue engineering. An extensive range of in vitro and in vivo tests has proven the favourable applicability of PCL in biomedicine, bringing about the FDA approval for a plethora of PCL made medical or drug delivery systems. This popular polymer, widely researched since the 1970s, can be readily processed through various techniques such as 3D printing and electrospinning to create biomimetic and customized medical products. However, low mechanical strength, insufficient number of cellular recognition sites, poor bioactivity, and hydrophobicity are main shortcomings of PCL limiting its broader use for biomedical applications. To maintain and benefit from the high potential of PCL, yet addressing its physicochemical and biological challenges, blending with nature-derived (bio)polymers and incorporation of nanofillers have been extensively investigated. Here, we discuss novel additives that have been meant for enhancement of PCL nanofiber properties and thus for further extension of the PCL nanofiber application domain. The most recent researches (since 2017) have been covered and an updated overview about hybrid PCL nanofibers is presented with focus on those including nature-derived additives, e.g., polysaccharides and proteins, and synthetic additives, e.g., inorganic and carbon nanomaterials.

Mussel-inspired functionalization of electrospun scaffolds with polydopamine-assisted immobilization of mesenchymal stem cells-derived small extracellular vesicles for enhanced bone regeneration

Mesenchymal stem cells-derived small extracellular vesicles (MSCs-sEV) have shown promising prospects as a cell-free strategy for bone tissue regeneration. Here, a bioactive MSCs-sEV-loaded electrospun silk fibroin/poly(ε-caprolactone) (SF/PCL) scaffold was synthesized via a mussel-inspired immobilization strategy assisted by polydopamine (pDA). This pDA modification endowed the as-prepared scaffold with high loading efficiency and sustained release profile of sEV. In addition, the fabricated composite scaffold exhibited good physiochemical, mechanical, and biocompatible properties. In vitro cellular experiments indicated that the MSCs-sEV-loaded composite scaffold promoted the adhesion and spreading of preosteoblast and endothelial cells, as well as enhanced osteogenic differentiation and angiogenic activity. In vivo experiments showed that the functionalized electrospun scaffolds promoted bone regeneration in a rat calvarial bone defect model. Results suggest that the developed MSCs-sEV-anchored pDA-modified SF/PCL electrospun scaffolds possess high application potential in bone tissue engineering owing to their powerful pro-angiogenic and -osteogenic capacities, cell-free bioactivity, and cost effectiveness.

Ionic conductive nanocomposite based on poly(l-lactic acid)/poly(amidoamine) dendrimerelectrospun nanofibrous for biomedical application

The modification of poly (l-lactic acid) (PLLA) electrospun nanofibrous scaffolds was carried out by blending with second-generation poly amidoamine (PAMAM) for enhancement of their ionic conductivity. The samples containing PLLA and various amounts of PAMAM (1%, 3%, 5%, and 7% by wt.) were fabricated by electrospinning techniques. The electrospun fibers were characterized using scanning electron microscopy (SEM), porosity, Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry, contact angle measurement, water uptake measurement, mechanical properties, and electrical properties. Furthermore,in vitrodegradation study and cell viability assay were investigated in biomaterial applications. Creating amide groups through aminolysis reaction was confirmed by FTIR analysis successfully. The results reveal that adding PAMAM caused an increase in fiber diameter, crystallinity percentage, hydrophilicity, water absorption, elongation-at-break, and OE-mesenchymal stem cell viability. It is worth mentioning that this is the first report investigating the conductivity of PLLA/PAMAM nanofiber. The results revealed that by increasing the amount of PAMAM, the ionic conductivity of scaffolds was enhanced by about nine times. Moreover, the outcomes indicated that the presence of PAMAM could improve the limitations of PLLA like hydrophobicity, lack of active group, and poor cell adhesion.

A review on allopathic and herbal nanofibrous drug delivery vehicles for cancer treatments

Drug delivery empowered with nanotechnology manifests to be a superior therapy to cancer. Electrospun nanofibers cocooning anti-cancerous drugs have shown tremendous cytotoxicity towards various tumor cells, including breast, brain, liver, and lung cancer cells. This pristine drug delivery system, according to literature, desists showing any undesirable effects on other parts of the body and bestows several other benefits. From nature-derived Curcumin to laboratory-made Doxorubicin, literature proclaims many such drugs used in nanofibrous drug delivery. Also, multi-drug delivery has been reported to exhibit enhanced properties. The present review exhibits the unrealized potential of nanofibrous drug delivery in chemotherapy.

Nano Iron Oxide-PCL Composite as an Improved Soft Tissue Scaffold

Iron oxide nanoparticles were employed to fabricate a soft tissue scaffold with enhanced physicochemical and biological characteristics. Growth promotion effect of L-lysine coated magnetite (Lys@Fe3O4) nanoparticles on the liver cell lines was proved previously. So, in the current experiment these nanoparticles were employed to fabricate a soft tissue scaffold with growth promoting effect on the liver cells. Lys@Fe3O4 nanoparticles were synthesized via co-precipitation reaction. Resulted particles were ~7 nm in diameter and various concentrations (3, 5, and 10 wt%) of these nanoparticles were used to fabricate nanocomposite PCL fibers. Electrospinning technique was employed and physicochemical characteristics of the resulted nanofibers were evaluated. Electron micrographs and EDX-mapping analysis showed that nanoparticles were well dispersed in the PCL fibers and no bead structure were formed. As expected, incorporation of Lys@Fe3O4 to the PCL nanofibers resulted in a reduction in hydrophobicity of the scaffold. Nanocomposite scaffolds were shown increased tensile strength with increasing concentration of employed nanoparticles. In contrast to PCL scaffold, nearly 150% increase in the cell viability was observed after 3-days exposure to the nanocomposite scaffolds. This study indicates that incorporation of magnetite nanoparticles in the PCL fibers make them more prone to cell attachment. However, incorporated nanoparticles can provide the attached cells with valuable iron element and consequently promote the cells growth rate. Based on the results, magnetite enriched PCL nanofibers could be introduced as a scaffold to enhance the biological performance for liver tissue engineering purposes.

Co-loading of doxorubicin and iron oxide nanocubes in polycaprolactone fibers for combining Magneto-Thermal and chemotherapeutic effects on cancer cells

Among the strategies to fight cancer, multi-therapeutic approaches are considered as a wise choice to put in place multiple weapons to suppress tumors. In this work, to combine chemotherapeutic effects to magnetic hyperthermia when using biocompatible scaffolds, we have established an electrospinning method to produce nanofibers of polycaprolactone loaded with magnetic nanoparticles as heat mediators to be selectively activated under alternating magnetic field and doxorubicin as a chemotherapeutic drug. Production of the fibers was investigated with iron oxide nanoparticles of peculiar cubic shape (at 15 and 23 nm in cube edges) as they provide benchmark heat performance under clinical magnetic hyperthermia conditions. With 23 nm nanocubes when included into the fibers, an arrangement in chains was obtained. This linear configuration of magnetic nanoparticles resemble that of the magnetosomes, produced by magnetotactic bacteria, and our magnetic fibers exhibited remarkable heating effects as the magnetosomes. Magnetic fiber scaffolds showed excellent biocompatibility on fibroblast cells when missing the chemotherapeutic agent and when not exposed to magnetic hyperthermia as shown by viability assays. On the contrary, the fibers containing both magnetic nanocubes and doxorubicin showed significant cytotoxic effects on cervical cancer cells following the exposure to magnetic hyperthermia. Notably, these tests were conducted at magnetic hyperthermia field conditions of clinical use. As here shown, on the doxorubicin sensitive cervical cancer cells, the combination of heat damage by magnetic hyperthermia with enhanced diffusion of doxorubicin at therapeutic temperature are responsible for a more effective oncotherapy.

The Blending of Poly(glycolic acid) with Polycaprolactone and Poly(l-lactide): Promising Combinations

Poly(glycolic acid) (PGA) holds unique properties, including high gas barrier properties, high tensile strength, high resistance to common organic solvents, high heat distortion temperature, high stiffness, as well as fast biodegradability and compostability. Nevertheless, this polymer has not been exploited at a large scale due to its relatively high production cost. As such, the combination of PGA with other bioplastics on one hand could reduce the material final cost and on the other disclose new properties while maintaining its “green” features. With this in mind, in this work, PGA was combined with two of the most widely applied bioplastics, namely poly(l-lactide) (PLLA) and poycaprolactone (PCL), using the melt blending technique, which is an easily scalable method. FE-SEM measurements demonstrated the formation of PGA domains whose dimensions depended on the polymer matrix and which turned out to decrease by diminishing the PGA content in the mixture. Although there was scarce compatibility between the blend components, interestingly, PGA was found to affect both the thermal properties and the degradation behavior of the polymer matrices. In particular, concerning the latter property, the presence of PGA in the blends turned out to accelerate the hydrolysis process, particularly in the case of the PLLA-based systems.

Development and Evaluation of a Human Skin Equivalent in a Semiautomatic Microfluidic Diffusion Chamber

There is an increasing demand for transdermal transport measurements to optimize topical drug formulations and to achieve proper penetration profile of cosmetic ingredients. Reflecting ethical concerns the use of both human and animal tissues is becoming more restricted. Therefore, the focus of dermal research is shifting towards in vitro assays. In the current proof-of-concept study a three-layer skin equivalent using human HaCaT keratinocytes, an electrospun polycaprolactone mesh and a collagen-I gel was compared to human excised skin samples. We measured the permeability of the samples for 2% caffeine cream using a miniaturized dynamic diffusion cell (“skin-on-a-chip” microfluidic device). Caffeine delivery exhibits similar transport kinetics through the artificial skin and the human tissue: after a rapid rise, a long-lasting high concentration steady state develops. This is markedly distinct from the kinetics measured when using cell-free constructs, where a shorter release was observable. These results imply that both the established skin equivalent and the microfluidic diffusion chamber can serve as a suitable base for further development of more complex tissue substitutes.

Electrospun Nanofibers for Cancer Therapy

Lately, a remarkable progress has been recorded in the field of electrospinning for the preparation of numerous types of nanofiber scaffolds. These scaffolds present some remarkable features including high loading capacity and encapsulation efficiency, superficial area and porosity, potential for modification, structure for the co-delivery of various therapies, and cost-effectiveness. Their present and future applications for cancer diagnosis and treatment are promising and pioneering. In this chapter we provide a comprehensive overview of electrospun nanofibers (ESNFs) applications in cancer diagnosis and treatment, covering diverse types of drug-loaded electrospun nanofibers.

Fundamentals and Current Strategies for Peripheral Nerve Repair and Regeneration

A body of evidence indicates that peripheral nerves have an extraordinary yet limited capacity to regenerate after an injury. Peripheral nerve injuries have confounded professionals in this field, from neuroscientists to neurologists, plastic surgeons, and the scientific community. Despite all the efforts, full functional recovery is still seldom. The inadequate results attained with the "gold standard" autograft procedure still encourage a dynamic and energetic research around the world for establishing good performing tissue-engineered alternative grafts. Resourcing to nerve guidance conduits, a variety of methods have been experimentally used to bridge peripheral nerve gaps of limited size, up to 30-40 mm in length, in humans. Herein, we aim to summarize the fundamentals related to peripheral nerve anatomy and overview the challenges and scientific evidences related to peripheral nerve injury and repair mechanisms. The most relevant reports dealing with the use of both synthetic and natural-based biomaterials used in tissue engineering strategies when treatment of nerve injuries is envisioned are also discussed in depth, along with the state-of-the-art approaches in this field.

Electrospun nanofibers in cancer research: from engineering of in vitro 3D cancer models to therapy

Electrospinning is historically related to tissue engineering due to its ability to produce nano-/microscale fibrous materials with mechanical and functional properties that are extremely similar to those of the extracellular matrix of living tissues. The general interest in electrospun fibrous matrices has recently expanded to cancer research both as scaffolds for in vitro cancer modelling and as patches for in vivo therapeutic delivery. In this review, we examine electrospinning by providing a brief description of the process and overview of most materials used in this process, discussing the effect of changing the process parameters on fiber conformations and assemblies. Then, we describe two different applications of electrospinning in service of cancer research: firstly, as three-dimensional (3D) fibrous materials for generating in vitro pre-clinical cancer models; and secondly, as patches encapsulating anticancer agents for in vivo delivery.

Fabrication techniques of biomimetic scaffolds in three-dimensional cell culture: A review

In the last four decades, several researchers worldwide have routinely and meticulously exercised cell culture experiments in two-dimensional (2D) platforms. Using traditionally existing 2D models, the therapeutic efficacy of drugs has been inappropriately validated due to the failure in generating the precise therapeutic response. Fortunately, a 3D model addresses the foregoing limitations by recapitulating the in vivo environment. In this context, one has to contemplate the design of an appropriate scaffold for favoring the organization of cell microenvironment. Instituting pertinent model on the platter will pave way for a precise mimicking of in vivo conditions. It is because animal cells in scaffolds oblige spontaneous formation of 3D colonies that molecularly, phenotypically, and histologically resemble the native environment. The 3D culture provides insight into the biochemical aspects of cell-cell communication, plasticity, cell division, cytoskeletal reorganization, signaling mechanisms, differentiation, and cell death. Focusing on these criteria, this paper discusses in detail, the diversification of polymeric scaffolds based on their available resources. The paper also reviews the well-founded and latest techniques of scaffold fabrication, and their applications pertaining to tissue engineering, drug screening, and tumor model development.

Tympanic Membrane Collagen Expression by Dynamically Cultured Human Mesenchymal Stromal Cell/Star-Branched Poly(ε-Caprolactone) Nonwoven Constructs

The tympanic membrane (TM) primes the sound transmission mechanism due to special fibrous layers mainly of collagens II, III, and IV as a product of TM fibroblasts, while type I is less represented. In this study, human mesenchymal stromal cells (hMSCs) were cultured on star-branched poly(ε-caprolactone) (*PCL)-based nonwovens using a TM bioreactor and proper differentiating factors to induce the expression of the TM collagen types. The cell cultures were carried out for one week under static and dynamic conditions. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to assess collagen expression. A Finite Element Model was applied to calculate the stress distribution on the scaffolds under dynamic culture. Nanohydroxyapatite (HA) was used as a filler to change density and tensile strength of *PCL scaffolds. In dynamically cultured *PCL constructs, fibroblast surface marker was overexpressed, and collagen type II was revealed via IHC. Collagen types I, III and IV were also detected. Von Mises stress maps showed that during the bioreactor motion, the maximum stress in *PCL was double that in HA/*PCL scaffolds. By using a *PCL nonwoven scaffold, with suitable physico-mechanical properties, an oscillatory culture, and proper differentiative factors, hMSCs were committed into fibroblast lineage-producing TM-like collagens.

Incorporation of graphene oxide into poly(ɛ-caprolactone) 3D printed fibrous scaffolds improves their antimicrobial properties

Implantable medical devices infection and consequent failure is a severe health issue, which can result from bacterial adhesion, growth, and subsequent biofilm formation at the implantation site. Graphene-based materials, namely graphene oxide (GO), have been described as potential antibacterial agents when immobilized and exposed in polymeric matrices. This work focuses on the development of antibacterial and biocompatible 3D fibrous scaffolds incorporating GO. Poly(ε-caprolactone) scaffolds were produced, with and without GO, using wet-spinning combined with additive manufacturing. Scaffolds with different GO loadings were evaluated regarding physical-chemical characterization, namely GO surface exposure, antibacterial properties, and ability to promote human cells adhesion. Antimicrobial properties were evaluated through live/dead assays performed with Gram-positive and Gram-negative bacteria. 2 h and 24 h adhesion assays revealed a time-dependent bactericidal effect in the presence of GO, with death rates of adherent S. epidermidis and E. coli reaching ~80% after 24 h of contact with scaffolds with the highest GO concentration. Human fibroblasts cultured for up to 14 days were able to adhere and spread over the fibers, independently of the presence of GO. Overall, this work demonstrates the potential of GO-containing fibrous scaffolds to be used as biomaterials that hinder bacterial infection, while allowing human cells adhesion.

Fabrication and Characterization of Composite Meshes Loaded with Antimicrobial Peptides

Biomaterials-centered infection or implant-associated infection plays critical roles in all areas of medicine with implantable devices. The widespread over use of antibiotics has caused severe bacterial resistance and even super bugs. Therefore, the development of anti-infection implantable devices with non-antibiotic-based new antimicrobial agents is indeed a priority for all of us. In this study, antimicrobial composite meshes were fabricated with broad-spectrum antimicrobial peptides (AMPs). Macroporous polypropylene meshes with poly-caprolactone electrospun nanosheets were utilized as a substrate to load AMPs and gellan gum presented as a media to gel with AMPs. Different amounts of AMPs were loaded onto gellan gum to determine the appropriate dose. The surface morphologies, Fourier-transform infrared spectroscopy spectra, in vitro release profiles, mechanical performances, in vitro antimicrobial properties, and cytocompatibility of composite scaffolds were evaluated. Results showed that AMPs were loaded into the meshes successfully, the in vitro release of AMPs in phosphate-buffered saline was prolonged, and less than 60% peptides were released in 10 days. The mechanical properties of composite meshes were also within the scope of several commercial surgical meshes. Composite meshes with the AMP loading amount of over 3 mg/cm² showed inhibition against both Gram-negative and Gram-positive bacteria effectively, while they presented no toxicity to mammalian cells even at a loading amount of 10 mg/cm². These results demonstrate a new simple and practicable method to offer antimicrobial properties to medical devices for hernia repair.

Sustained Local Delivery of Diclofenac from Three-Dimensional Ultrafine Fibrous Protein Scaffolds with Ultrahigh Drug Loading Capacity

The three-dimensional (3D) ultrafine fibrous scaffolds loaded with functional components can not only provide support to 3D tissue repair, but also deliver the components in-situ with small dosage and low fusion frequency. However, the conventional loading methods possess drawbacks such as low loading capacity or high burst release. In this research, an ultralow concentration phase separation (ULCPS) technique was developed to form 3D ultrafine gelatin fibers and, meanwhile, load an anti-inflammatory drug, diclofenac, with high capacities for the long-term delivery. The developed scaffolds could achieve a maximum drug loading capacity of 12 wt.% and a highest drug loading efficiency of 84% while maintaining their 3D ultrafine fibrous structure with high specific pore volumes from 227.9 to 237.19 cm3/mg. The initial release at the first hour could be reduced from 34.7% to 42.2%, and a sustained linear release profile was observed with a rate of about 1% per day in the following 30 days. The diclofenac loaded in and released from the ULCPS scaffolds could keep its therapeutic molecular structure. The cell viability has not been affected by the release of drug when the loading was less than 12 wt.%. The results proved the possibility to develop various 3D ultrafine fibrous scaffolds, which can supply functional components in-situ with a long-term.

Morphology and Properties of Electrospun PCL and Its Composites for Medical Applications: A Mini Review

Polycaprolactone (PCL) is one of the most used synthetic polymers for medical applications due to its biocompatibility and slow biodegradation character. Combining the inherent properties of the PCL matrix with the characteristic of nanofibrous particles, result into promising materials that can be suitable for different applications, including the biomedical applications. The advantages of nanofibrous structures include large surface area, a small diameter of pores and a high porosity, which make them of great interest in different applications. Electrospinning, as technique, has been heavily used for the preparation of nano- and micro-sized fibers. This review discusses the different methods for the electrospinning of PCL and its composites for advanced applications. Furthermore, the steady state conditions as well as the effect of the electrospinning parameters on the resultant morphology of the electrospun fiber are also reported.

Preparation and in Vitro Evaluation of New Composite Mesh Functionalized with Cationic Antimicrobial Peptide

Infection caused by bacteria in hernia repair site is a severe complication, and patients have to undergo a second surgery to remove the infected prosthesis. In this study, we developed a composite biological safe mesh with antibacterial activity. The composite mesh is composed of large pore polypropylene (PP) mesh, poly-caprolactone (PCL) and antimicrobial peptide (PEP-1), which we synthesized in our lab. Fourier transformed infrared (FTIR) spectroscopy was utilized to analyze the functional groups. The surface morphology, in vitro release characters, mechanical properties, antibacterial activities, and in vitro cytotoxicity of modified mesh were evaluated. Results showed that PEP-1 was loaded in fibers successfully and could diffuse from nanofibers to inhibit bacteria (E. coli) growth. However, the modified mesh did not show inhibition to S. aureus. The mechanical properties of fabricated mesh showed no difference with two commercial surgical meshes. What is more, modified mesh was proved to be nontoxic to human dermal fibroblasts, indicating that this method to fabricate meshes with antibacterial activity is feasible and provides a new strategy for the development of surgical meshes.

PCL-Based Composite Scaffold Matrices for Tissue Engineering Applications

Biomaterial-based scaffolds are important cues in tissue engineering (TE) applications. Recent advances in TE have led to the development of suitable scaffold architecture for various tissue defects. In this narrative review on polycaprolactone (PCL), we have discussed in detail about the synthesis of PCL, various properties and most recent advances of using PCL and PCL blended with either natural or synthetic polymers and ceramic materials for TE applications. Further, various forms of PCL scaffolds such as porous, films and fibrous have been discussed along with the stem cells and their sources employed in various tissue repair strategies. Overall, the present review affords an insight into the properties and applications of PCL in various tissue engineering applications.

Nanoparticles in an antibiotic-loaded nanomesh for drug delivery

Antibiotic loaded nanomeshes were fabricated by electrospinning polycaprolactone, a biocompatible polymer, with 12.5% w/w Colistin, 1.4% w/w Vancomycin and either cationic or anionic gold nanoparticles in varying combinations. The resulting nanomeshes had different antibiotic release profiles, with citrate capped gold nanoparticles combined with Colistin having the highest sustained release over 14 days for a 4 mg, 1.5 cm² nanomesh. The electrospinning parameters were optimised to ensure the spinning of a homogenous mesh and the addition of antibiotics was confirmed through ¹H NMR and ATR-FTIR. This research, as a proof of concept, suggests an opportunity for fabricating nanomeshes which contain gold nanoparticles as a drug release mechanism for antibiotics.

The addition of gold nanoparticles to an antibiotic embedded nanomesh altered the amount of antibiotics released over 14 days.

Electrospun Nanomaterials Implementing Antibacterial Inorganic Nanophases

Electrospinning is a versatile, simple, and low cost process for the controlled production of fibers. In recent years, its application to the development of multifunctional materials has encountered increasing success. In this paper, we briefly overview the general aspects of electrospinning and then we focus on the implementation of inorganic nanoantimicrobials, e.g., nanosized antimicrobial agents in electrospun fibers. The most relevant characteristics sought in nanoantimicrobials supported on (or dispersed into) polymeric materials are concisely discussed as well. The interesting literature issued in the last decade in the field of antimicrobial electrospun nanomaterials is critically described. A classification of the most relevant studies as a function of the different approaches chosen for incorporating nanoantimicrobials in the final material is also provided.