3D superhydrophobic electrospun meshes as reinforcement materials for sustained local drug delivery against colorectal cancer cells

Intraperitoneal drug delivery systems for peritoneal carcinomatosis: Bridging the gap between research and clinical implementation

Several abdominal-located cancers develop metastasis within the peritoneum, what is called peritoneal carcinomatosis (PC), constituting a clinical challenge in their therapeutical management, often leading to poor prognoses. Current multidisciplinary strategies, including cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC), demonstrate efficacy but have limitations. In response, alternative strategies are explored in the drug delivery field for intraperitoneal chemotherapy. Controlled drug delivery offers a promising avenue, maintaining localized drug concentrations for optimal PC management. Drug delivery systems (DDS), including hydrogels, implants, nanoparticles, and hybrid systems, show potential for sustained and region-specific drug release. The present review aims to offer an overview of the advances and current designs of DDS for PC chemotherapy administration, focusing on their composition, main characteristics, and principal experimental outcomes, highlighting the importance of biomaterial rationale design and in vitro/vivo models for their testing. Moreover, since clinical data for human subjects are scarce, we offer a critical discussion of the gap between bench and bedside in DDS translation, emphasizing the need for further research.

Delivering umbilical cord mesenchymal stem cell exosomes through hydrogel ameliorates vaginal atrophy in ovariectomized rats

BACKGROUND

Menopausal and postmenopausal women often experience vaginal atrophy due to estrogen deficiency. Mesenchymal stem cell exosomes have emerged as potential therapeutic agents, capable of promoting tissue regeneration and repair.

OBJECTIVE

This study aimed to explore the benefits of exosomes on VK2 cells and the therapeutic effect of topical exosomal hydrogel on atrophic vaginas.

METHODS

Exosomes were extracted using the high-speed centrifugation method, and their effects on VK2 cell proliferation, migration, and differentiation were observed through co-culture. The menopause model was induced by ovariectomy in rats, followed by the injection of exosome-loaded hydrogel into their vaginas. The treatment's effectiveness was evaluated by measuring vaginal epithelium thickness using HE staining, and assessing vaginal mucosa proliferation and lamina propria angiogenesis using Ki67 and anti-CD31 staining, respectively.

RESULTS

Exosomes significantly promoted VK2 cell proliferation and migration, but had no significant effect on differentiation. The exosome hydrogel increased the expression of Ki67 and CD31, leading to a significant improvement in epithelial thickness.

CONCLUSIONS

UcMSC- ex can stimulate the proliferation and migration of VK2 cells, but do not appear to promote differentiation. Topical application of exosome hydrogel enhances vaginal epithelium thickness to a certain degree, offering a promising non-hormonal therapeutic strategy to alleviate vaginal atrophy in postmenopausal women.

Insulin-like growth factor binding protein 4 loaded electrospun membrane ameliorating tendon injury by promoting retention of IGF-1

Tendon injury is one of the most common musculoskeletal disorders that impair joint mobility and lower quality of life. The limited regenerative capacity of tendon remains a clinical challenge. Local delivery of bioactive protein is a viable therapeutic approach for tendon healing. Insulin-like growth factor binding protein 4 (IGFBP-4) is a secreted protein capable of binding and stabilizing insulin-like growth factor 1 (IGF-1). Here, we applied an aqueous-aqueous freezing-induced phase separation technology to obtain the IGFBP4-encapsulated dextran particles. Then, we added the particles into poly (L-lactic acid) (PLLA) solution to fabricate IGFBP4-PLLA electrospun membrane for efficient IGFBP-4 delivery. The scaffold showed excellent cytocompatibility and a sustained release of IGFBP-4 for nearly 30 days. In cellular experiments, IGFBP-4 promoted tendon-related and proliferative markers expression. In a rat Achilles tendon injury model, immunohistochemistry and quantitative real-time polymerase chain reaction confirmed better outcomes by using the IGFBP4-PLLA electrospun membrane at the molecular level. Furthermore, the scaffold effectively promoted tendon healing in functional performance, ultrastructure and biomechanical properties. We found addition of IGFBP-4 promoted IGF-1 retention in tendon postoperatively and then facilitated protein synthesis via IGF-1/AKT signaling pathway. Overall, our IGFBP4-PLLA electrospun membrane provides a promising therapeutic strategy for tendon injury.

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.

Electrospun nanofibers for 3-D cancer models, diagnostics, and therapy

As one of the leading causes of global mortality, cancer has prompted extensive research and development to advance efficacious drug discovery, sustained drug delivery and improved sensitivity in diagnosis. Towards these applications, nanofibers synthesized by electrospinning have exhibited great clinical potential as a biomimetic tumor microenvironment model for drug screening, a controllable platform for localized, prolonged drug release for cancer therapy, and a highly sensitive cancer diagnostic tool for capture and isolation of circulating tumor cells in the bloodstream and for detection of cancer-associated biomarkers. This review provides an overview of applied nanofiber design with focus on versatile electrospinning fabrication techniques. The influence of topographical, physical, and biochemical properties on the function of nanofiber assemblies is discussed, as well as current and foreseeable barriers to the clinical translation of applied nanofibers in the field of oncology.

Drug-loaded PCL electrospun nanofibers as anti-pancreatic cancer drug delivery systems

Cancer is one of the main causes of death worldwide, being pancreatic cancer the second deadliest cancer in Western countries. Surgery, chemotherapy and radiotherapy form the basis of pancreatic cancer’s current treatment. However, these techniques have several disadvantages, such as surgery complications, chemotherapy systemic side effects and cancer recurrence. Drug delivery systems can reduce side effects, increasing the effectivity of the treatment by a controlled release at the targeted tumor cells. In this context, coaxial electrospun fibers can increase the control on the release profile of the drug. The aim of this study was to encapsulate and release different anticancer drugs (5-Fluorouracil and Methotrexate) from a polymeric fiber mat. Different flows and ratios were used to test their effect on fiber morphology, FTIR spectrum, drug encapsulation and release. Good integration of the anticancer drugs was observed and the use of a desiccator for 24 h showed to be a key step to remove solvent remanence. Moreover, the results of this study demonstrated that the polymeric solution could be used to encapsulate and release different drugs to treat cancers. This makes coaxial electrospinning a promising alternative to deliver complex chemotherapies that involve more than one drug, such as FOLFIRINOX, used in pancreatic cancer treatment.

Electrospun Nanofibers Revisited: An Update on the Emerging Applications in Nanomedicine

Electrospinning (ES) has become a straightforward and customizable drug delivery technique for fabricating drug-loaded nanofibers (NFs) using various biodegradable and non-biodegradable polymers. One of NF's pros is to provide a controlled drug release through managing the NF structure by changing the spinneret type and nature of the used polymer. Electrospun NFs are employed as implants in several applications including, cancer therapy, microbial infections, and regenerative medicine. These implants facilitate a unique local delivery of chemotherapy because of their high loading capability, wide surface area, and cost-effectiveness. Multi-drug combination, magnetic, thermal, and gene therapies are promising strategies for improving chemotherapeutic efficiency. In addition, implants are recognized as an effective antimicrobial drug delivery system overriding drawbacks of traditional antibiotic administration routes such as their bioavailability and dosage levels. Recently, a sophisticated strategy has emerged for wound healing by producing biomimetic nanofibrous materials with clinically relevant properties and desirable loading capability with regenerative agents. Electrospun NFs have proposed unique solutions, including pelvic organ prolapse treatment, viable alternatives to surgical operations, and dental tissue regeneration. Conventional ES setups include difficult-assembled mega-sized equipment producing bulky matrices with inadequate stability and storage. Lately, there has become an increasing need for portable ES devices using completely available off-shelf materials to yield highly-efficient NFs for dressing wounds and rapid hemostasis. This review covers recent updates on electrospun NFs in nanomedicine applications. ES of biopolymers and drugs is discussed regarding their current scope and future outlook.

Narrative review of gene modification: applications in three-dimensional (3D) bioprinting

Objective

This article focused on the application scenarios of three-dimensional (3D) bioprinting and gene-editing technology in various medical fields, including gene therapy, tissue engineering, tumor microenvironment simulation, tumor model construction, cancer regulation and expression, osteogenesis, and skin and vascular regeneration, and summarizing its development prospects and shortcomings.

Background

3D bioprinting is a process based on additive manufacturing that uses biological materials as the microenvironment living cells. The scaffolds and carriers manufactured by 3D bioprinting technology provide a safe, efficient, and economical platform for genes, cells, and biomolecules. Gene modification refers to replacing, splicing, silencing, editing, controlling or inactivating genes and delivering new genes. The combination of this technology that changes cell function or cell fate or corrects endogenous mutations and 3D bioprinting technology has been widely used in various medical field.

Methods

We conducted a literature search for papers published up to March 2021 on the gene modification combined with 3D bioprinting in various medical fields via PubMed, Web of Science, China National Knowledge Infrastructure (CNKI). The following medical subject heading terms were included for a MEDLINE search: “3D printing/gene editing”, “3D printing/genetic modification”, “3D printing/seed cell”, “bioprinting/gene editing”, “bioprinting/genetic modification”, “bioprinting/seed cell”, “scaffold/gene editing”, “scaffold/genetic modification”, “scaffold/seed cell”, “gene/scaffold”, “gene/bioprinting”, “gene/3D printing”. Quantitative and qualitative data was extracted through interpretation of each article.

Conclusions

We have reviewed the application scenarios of 3D bioprinting and gene-editing technology in various medical fields, it provides an efficient and accurate delivery system for personalized tumor therapy, enhancing the targeting effect while maintaining the integrity of the fabricated structure. It exhibits significant application potential in developing tumor drugs. In addition, scaffolds obtained via 3D bioprinting provide gene therapy applications for skin and bone healing and repair and inducing stem cell differentiation. It also considers the future development direction in this field, such as the emergence and development of gene printing, 4D printing. The combination of nanotechnology and gene printing may provide a new way for future disease research and treatment.

Electrospun Membranes as a Porous Barrier for Molecular Transport: Membrane Characterization and Release Assessment

Electrospun nanofibers have been extensively studied for encapsulated drugs releasing from the inside of the fiber matrix, but have been barely looked at for their potential to control release as a semi-permeable membrane. This study investigated molecular transport behaviors across nanofiber membranes with different micro-structure sizes and compositions. Four types of membranes were made by 5% and 10% poly (ε-caprolactone) (PCL) solutions electro-spun with or without 50 nm calcium carbonate (CaCO3) nanoparticles. The membranes were tested for thickness, fiber diameter, pore size, porosity, tensile strength and elongation, contact angle of water and their impacts on molecular transport behaviors. The presence of the CaCO3 nanoparticles made the 5% membranes stronger and stiffer but the 10% membranes weaker and less stiff due to the different (covering or embedded) locations of the nanoparticles with the corresponding fibers. Solute transport studies using caffeine as the model drug found the 5% membranes further retarded release from the 10% membranes, regardless of only half the amount of material being used for synthesis. The addition of CaCO3 nanoparticles aided the water permeation process and accelerated initial transports. The difference in release profiles between 5% and 10% membranes suggests different release mechanisms, with membrane-permeability dominated release for 5% PCL membranes and solute-concentration-gradient dominated release for 10% PCL membranes.

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.

In Vivo Degradation Mechanisms of Aliphatic Polycarbonates and Functionalized Aliphatic Polycarbonates

Aliphatic polycarbonates (APCs) have been studied for decades but have not been as utilized as aliphatic polyesters in biomaterial applications such as drug delivery and tissue engineering. With the recognition that functionalized aliphatic polymers can be readily synthesized, increased attention is being paid to these materials. A frequently provided reason for utilizing these polymers is that they degrade to form diols and carbon dioxide. However, depending on the structure and molecular weight of the APC, degradation may not occur. In this review, the mechanisms by which APCs and functionalized APCs have been found to degrade in vivo are examined with the objective of providing guidance in the continued development of these polymers as biomaterials.

Reinforced electrospun nanofiber composites for drug delivery applications

Electrospun technology becomes a valuable means of fabricating functional polymeric nanofibers with distinctive morphological properties for drug delivery applications. Nanofibers are prepared from the polymer solution, which allows the direct incorporation of therapeutics such as small drug molecules, genes, and proteins by merely mixing them into the polymeric solution. Due to their biocompatibility, adhesiveness, sterility, and efficiency in delivering diverse cargoes, electrospun nanofibers have gained much attention. This review discusses the capabilities of the electrospun nanofibers in delivering different therapeutics like small molecules, genes, and proteins to their desired target site for treating various ailments. The potential of nanofibers in administering through multiple administration routes and the associated challenges has also been expounded along with a cross-talk about the commercial products of nanofibers for biomedical applications.

New Strategies for Safe Cancer Therapy Using Electrospun Nanofibers: A Short Review

Electrospun nanofibers regarding their special features, including high drug loading capacity, high surface to volume area, flexibility, and ease of production and operation, are of great interest for being used in tissue engineering, and drug delivery approaches. In this context, several studies have been done for the production of biodegradable and biocompatible scaffolds containing different anticancer agents for fighting with solid tumors. Surprisingly, these scaffolds are able to deliver different combinations of drugs and agents, such as nanoparticles and release them in a time dependent manner. Here in this review, we summarize the principles of electrospinning and their uses in entrapment of drugs and anti-proliferative agents suitable for cancer therapy. The latest studies performed on treating cancer using electrospinning are mentioned and their advantages and disadvantages over conventional treatment methods are discussed.

Fabrication and in vitro evaluation of thermally cross-linked gelatin nanofibers for drug delivery applications

In this study, four different nanofibers consisting of gelatin (Gel), doxorubicin (DOX) with gel (DOX@Gel), a composite of gel with poly(ethylene glycol) (PEGylated-gel), and DOX@PEGylated-gel were fabricated. Subsequently, the nanofibers were thermally cross-linked in order to offer a stable and biocompatible alternative for the biological applications of nanofibers such as drug delivery and tissue engineering. Nanofibers were characterized by scanning electron microscopy, Fourier Transform-Infrared Spectroscopy (FT-IR), and confocal microscopy. The formation of smooth, continuous, and uniform nanofibers was observed and the addition of PEG resulted in an increase whereas the incorporation of DOX into nanofibers had no significant change in the diameter of nanofibers. Crosslinking also enlarged the diameter of all nanofibers and the most dramatic increase was observed 53% by DOX@PEGylated-gel. Afterward, the biological performance of the nanofibers was investigated by drug release profile, cytotoxicity on A549 cell line as well as antimicrobial activity with E. coli and S. aureus. The results indicate an enhanced drug release profile, moderate antimicrobial activity, and reasonable cytotoxic efficiency for thermally cross-linked nanofibers compared to uncross-linked nanofibers.

A Smart Hyperthermia Nanofiber-Platform-Enabled Sustained Release of Doxorubicin and 17AAG for Synergistic Cancer Therapy

This study demonstrates the rational fabrication of a magnetic composite nanofiber mesh that can achieve mutual synergy of hyperthermia, chemotherapy, and thermo-molecularly targeted therapy for highly potent therapeutic effects. The nanofiber is composed of biodegradable poly(ε-caprolactone) with doxorubicin, magnetic nanoparticles, and 17-allylamino-17-demethoxygeldanamycin. The nanofiber exhibits distinct hyperthermia, owing to the presence of magnetic nanoparticles upon exposure of the mesh to an alternating magnetic field, which causes heat-induced cell killing as well as enhanced chemotherapeutic efficiency of doxorubicin. The effectiveness of hyperthermia is further enhanced through the inhibition of heat shock protein activity after hyperthermia by releasing the inhibitor 17-allylamino-17-demethoxygeldanamycin. These findings represent a smart nanofiber system for potent cancer therapy and may provide a new approach for the development of localized medication delivery.

Multidrug-loaded electrospun micro/nanofibrous membranes: Fabrication strategies, release behaviors and applications in regenerative medicine

Electrospun micro/nanofibrous membranes (EFMs) have been widely investigated as local drug delivery systems. Multiple drugs can be simultaneously incorporated into one EFM to create synergistic effects, reduce side effects, and play their respective roles in the complex physiological processes of tissue regeneration and postoperative adhesion prevention. Due to the versatile electrospinning techniques, sustained and programmed release behaviors of multiple drugs could be achieved by modulating the structure of the EFMs and the location of the drugs. In this review, various multidrug incorporation approaches based on electrospinning are overviewed. In particular, the advantages and limitations of each drug incorporation technique, the methods to control drug release and the effect of one drug release on another are discussed. Then the applications of multidrug-loaded EFMs in regenerative medicine, including wound healing, bone regeneration, vascular tissue engineering, nerve regeneration, periodontal regeneration and adhesion prevention are comprehensively reviewed. Finally, the future perspectives and challenges in the research of multidrug-loaded EFMs are discussed.

Adipose tissue-derived mesenchymal stem cells for breast tissue regeneration

With an escalating incidence of breast cancer cases all over the world and the deleterious psychological impact that mastectomy has on patients along with several limitations of the currently applied modalities, it's plausible to seek unconventional approaches to encounter such a burgeoning issue. Breast tissue engineering may allow that chance via providing more personalized solutions which are able to regenerate, mimicking natural tissues also facing the witnessed limitations. This review is dedicated to explore the utilization of adipose tissue-derived mesenchymal stem cells for breast tissue regeneration among postmastectomy cases focusing on biomaterials and cellular aspects in terms of harvesting, isolation, differentiation and new tissue formation as well as scaffolds types, properties, material-host interaction and an in vitro breast tissue modeling.

Polyglycerol Hyperbranched Polyesters: Synthesis, Properties and Pharmaceutical and Biomedical Applications

In a century when environmental pollution is a major issue, polymers issued from bio-based monomers have gained important interest, as they are expected to be environment-friendly, and biocompatible, with non-toxic degradation products. In parallel, hyperbranched polymers have emerged as an easily accessible alternative to dendrimers with numerous potential applications. Glycerol (Gly) is a natural, low-cost, trifunctional monomer, with a production expected to grow significantly, and thus an excellent candidate for the synthesis of hyperbranched polyesters for pharmaceutical and biomedical applications. In the present article, we review the synthesis, properties, and applications of glycerol polyesters of aliphatic dicarboxylic acids (from succinic to sebacic acids) as well as the copolymers of glycerol or hyperbranched polyglycerol with poly(lactic acid) and poly(ε-caprolactone). Emphasis was given to summarize the synthetic procedures (monomer molar ratio, used catalysts, temperatures, etc.,) and their effect on the molecular weight, solubility, and thermal and mechanical properties of the prepared hyperbranched polymers. Their applications in pharmaceutical technology as drug carries and in biomedical applications focusing on regenerative medicine are highlighted.

Robust Superhydrophobic Membrane for Membrane Distillation with Excellent Scaling Resistance

We report in this study a scalable and controllable approach for fabricating robust and high-performance superhydrophobic membranes for membrane distillation (MD). This novel approach combines electro-co-spinning/spraying (ES²) with chemical vapor welding and enables the formation of robust superhydrophobic (r-SH) membranes that are mechanically strong, highly porous, and robustly superhydrophobic. Compared with superhydrophobic membranes obtained using surface deposition of fluorinated nanoparticles, the r-SH membranes have more robust wetting properties and higher vapor permeability in MD. MD scaling experiments with sodium chloride and gypsum show that the r-SH membrane is highly effective in mitigating mineral scaling. Finally, we also discuss the mechanism of scaling resistance enabled by superhydrophobic membranes with a highlight on the roles of the surface-bound air layer in reducing the crystal-membrane contact area, nucleation propensity, and ion-membrane contact time.

Core-shell nanofibers as drug delivery systems

Core-shell nanofibers have grown in popularity over the last decade owing to their special features and their many applications in biomedicine. They can be produced by electrospinning of immiscible polymer blends or emulsions through a single nozzle or by electrospinning using a coaxial nozzle. Several of the electrospinning parameters allow great versatility for the compositions and diameters of core-shell nanofibers to be produced. Morphology of core-shell nanofibers can be investigated using transmission electron microscopy and, in some cases, scanning electron microscopy. Several studies have shown that core-shell nanofibers have some advantages over monolithic nanofibers, such as better drug, protein, gene or probiotic incorporation into the nanofibers, greater control over drug release, and maintenance of protein structure and activity during electrospinning. We herein review the production and characterization of core-shell nanofibers, the critical parameters that affect their development, and their advantages as delivery systems.

Assessment of Super-Hydrophobic Textured Coatings on AA6082 Aluminum Alloy

Superhydrophobicity is one of the most required surface properties for a wide range of application such as self-cleaning, anti-corrosion, oil-water separation, anti-icing, and anti-bioadhesion. Recently, several methods have been developed to produce nature inspired super-hydrophobic surfaces. Nevertheless, these methods require a complicated process and expensive equipment. In order to overcome these issues, we propose three different methods to obtain nature-inspired super-hydrophobic surfaces: short-term treatment with boiling water, HF/HCl and HNO3/HCl concentrated solution etching. Afterwards, a thin layer of octadecylsilane was applied by in situ polymerization on all pre-treated surfaces. Eventually, all substrates were dried for 3 h at 100 °C to complete the silane curing. Scanning electron microscopy (SEM), contact angle measuring system and atomic force microscope (AFM) were used to characterize the surfaces. Surface morphology analysis showed that each method results in a specific dual hierarchical nano-/micro-structure. The corresponding water contact angles ranged from 160° to nearly 180°. The best results were observed for HF etched Al 6082 surface were water contact angle above 175° was achieved. Furthermore, a scheme able to assess the relationship between hydrophobic behavior and surface morphology was finally proposed.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospun Nanofibers: Recent Applications in Drug Delivery and Cancer Therapy

Polymeric nanofibers (NFs) have been extensively reported as a biocompatible scaffold to be specifically applied in several researching fields, including biomedical applications. The principal researching lines cover the encapsulation of antitumor drugs for controlled drug delivery applications, scaffolds structures for tissue engineering and regenerative medicine, as well as magnetic or plasmonic hyperthermia to be applied in the reduction of cancer tumors. This makes NFs useful as therapeutic implantable patches or mats to be implemented in numerous biomedical researching fields. In this context, several biocompatible polymers with excellent biocompatibility and biodegradability including poly lactic-co-glycolic acid (PLGA), poly butylcyanoacrylate (PBCA), poly ethylenglycol (PEG), poly (ε-caprolactone) (PCL) or poly lactic acid (PLA) have been widely used for the synthesis of NFs using the electrospun technique. Indeed, other types of polymers with stimuli-responsive capabilities has have recently reported for the fabrication of polymeric NFs scaffolds with relevant biomedical applications. Importantly, colloidal nanoparticles used as nanocarriers and non-biodegradable structures have been also incorporated by electrospinning into polymeric NFs for drug delivery applications and cancer treatments. In this review, we focus on the incorporation of drugs into polymeric NFs for drug delivery and cancer treatment applications. However, the principal novelty compared with previously reported publications is that we also focus on recent investigations concerning new strategies that increase drug delivery and cancer treatments efficiencies, such as the incorporation of colloidal nanoparticles into polymeric NFs, the possibility to fabricate NFs with the capability to respond to external environments, and finally, the synthesis of hybrid polymeric NFs containing carbon nanotubes, magnetic and gold nanoparticles, with magnetic and plasmonic hyperthermia applicability.

Injectable thermosensitive hydrogel systems based on functional PEG/PCL block polymer for local drug delivery

Injectable in situ thermosensitive hydrogels have potential applications in tissue engineering and drug delivery. The hydrogel formulations exist as aqueous solutions at room temperature but rapidly solidify into gels at 37 °C in situ, making them highly suitable for administering drugs in a minimally invasive manner to the target organ(s). The hydrogel formed with nanoparticles assembled with amphiphilic polymer blocks of polyethyleneglycol (PEG) and biodegradable polycaprolactone (PCL) have been tested as platforms for targeted and sustained drug delivery, and have shown encouraging results. In this review, we summarize the influence of the molecular weight, PEG/PCL ratio and functional structure of hydrophobic PCL blocks on the critical gelation temperature, gelling behavior and drug release kinetics of the hydrogels. The current studies on the biomedical applications of thermosensitive PEG/PCL hydrogels have also been discussed.

In situ-forming and pH-responsive hydrogel based on chitosan for vaginal delivery of therapeutic agents

One of the important routes of drug administration for localized delivery of contraceptives and cervical cancer treatment agents is vaginal canal. Due to the low pH of vagina, a pH-responsive drug delivery system was developed. This hydrogel was synthesized based on a mucoadhesive biopolymer, chitosan (CS), that promotes the interaction between the hydrogel and mucosal surface of the vagina, potentially increasing the residence time of the system. This injectable hydrogel was formed via acid-labile Schiff-base linkages between free amine groups and aldehyde functionalities on modified chitosan. A novel approach was taken to add aldehyde functionalities to chitosan using a two-step reaction. Two types of slow and fast degrading hydrogels were prepared and loaded with iron (II) gluconate dihydrate, a non-hormonal spermicide, and doxorubicin hydrochloride, an anti-cancer drug. The release profiles of these drugs at different pH environments were assessed to determine the pH-dependent release mechanism. Mechanical properties, swell-ability and degradation rate of these matrices were studied. The cross-linking density of the hydrogel as well as pH changes played an important role in the characteristic of these hydrogels. The hydrogels degraded faster in lower pH, while the hydrogel with lower cross-linking density showed longer gelation time and faster degradation rate compared to the gel with higher cross-linking density. In vitro cytotoxicity assessment of these hydrogels in 48 h indicated the non-toxic effect of these hydrogels toward mesenchymal stem cells (MSCs) in the test period.

Localized Controlled Delivery of Gemcitabine via Microsol Electrospun Fibers to Prevent Pancreatic Cancer Recurrence

The low radical surgery rate of pancreatic cancer leads to increased local recurrence and poor prognosis. Gemcitabine (GEM) is the preferred chemotherapeutic for pancreatic cancer. However, systemic chemotherapy with GEM has reached a bottleneck due to its serious side effects after frequent injections. In this study, GEM is successfully enwrapped into electrospun fibers via microsol electrospinning technology to form a stable core-shell fibrous structure. The GEM release rate can be adjusted by altering the thickness of the hyaluronan-sol inner fiber and the quantity of loaded GEM, and the release can be sustained for as long as three weeks. In vitro assays show that these electrospun fibers effectively inhibit pancreatic cancer cells and promote apoptosis. In vivo studies show that the fibrous membranes are better for inhibiting the growth of residual tumors than that of integrated tumors. Furthermore, immunohistochemistry results show that GEM-loaded fibers promote a higher cell apoptosis rate than does systemically injected GEM in residual tumors. In addition, the local delivery of GEM with fibers significantly reduces liver toxicity. In summary, a core-shell electrospun fiber for the controlled and localized delivery of GEM, which greatly improves the treatment of residual tumors and prevents pancreatic tumor recurrence, is developed.

Exploring Peyer's Patch Uptake as a Strategy for Targeted Lung Delivery of Polymeric Rifampicin Nanoparticles

Uptake of nanoparticles through Peyer's Patches following oral administration could enable translocation through lymph to lymphatic organs like the lungs. An important consideration, however, is nanosize and particle hydrophobicity. Furthermore, as delivering the nanoparticles to the intestine where the Peyer's Patches are localized is important, their intact and rapid transit through the stomach into the intestine is highly desirable. We report hydrophobization of mucoadhesive Rifampicin-GantrezAN-119 nanoparticles (GzNP) using a hydrophobic polymer, ethyl cellulose (EC), with the objectives of augmenting Peyer's Patch uptake due to enhanced hydrophobicity and increased intestinal localization as a result of decreased mucoadhesion. RIF-Gantrez-EC nanoparticles (ECGzNP2) exhibited >13% RIF loading and an average particle size of 400-450 nm, which is appropriate for translation through lymph following Peyer's Patch uptake. Higher contact angle (67.3 ± 3.5° vs 30.3 ± 2.1°) and lower mucoadhesion (30.7 ± 4.8 g vs 87.0 ± 3.0 g) of ECGzNP2 over GzNP confirmed hydrophobization and lower mucoadhesion. Fluorescence photomicrographs of intraduodenally administered coumarin-labeled RIF-NP in rats demonstrated higher Peyer's Patch uptake with ECGzNP2, while the increased lung/plasma RIF ratio signified lymph mediated lung targeting. The gastrointestinal transit study in rats, which revealed a significantly higher intestine-to-stomach accumulation ratio with ECGzNP2 (3.4) compared to GzNP (1.0) [ p < 0.05], confirmed availability of the NP in the intestine for Peyer's Patch uptake. Such uptake enabled 182.4 ± 22.6% increase in relative bioavailability, a ∼2-fold higher plasma AUC/MIC ratio and significantly higher lung concentration with ECGzNP2, thereby proposing better efficacy. A significantly higher lung/liver ratio with ECGzNP2 also suggested lower hepatic exposure. The repeated dose 28-day oral toxicity study demonstrated the safety of the nanocarrier and reduced hepatotoxicity with ECGzNP2 compared to RIF. We hereby demonstrate uptake of orally administered NP through Peyer's Patches as a feasible strategy for lung targeting.

Impact of PCL nanofiber mat structural properties on hydrophilic drug release and antibacterial activity on periodontal pathogens

Electrospinning enables to design and manufacture novel drug delivery systems capable of advancing the local antibacterial therapy. In this study, two hydrophilic drugs - metronidazole and ciprofloxacin hydrochloride - were loaded both individually and in combination into hydrophobic poly(ε-caprolactone) (PCL) matrix using electrospinning. We aimed to develop prolonged release drug delivery systems suitable for the treatment of periodontal diseases and understand how different rarely studied structural features, such as nanofiber mat thickness, surface area, wettability, together with intrinsic properties, like solid state and localization of incorporated drugs in nanofibers, affect the drug release. Furthermore, the safety of nanofiber mats was assessed in vitro on fibroblasts, and their antibacterial activity was tested on selected strains of periodontopathogenic bacteria. The results showed that the structural properties of nanofiber mat are crucial in particular drug-polymer combinations, affecting the drug release and consequently the antibacterial activity. The hydrophobicity of a PCL nanofiber mat and its thickness are the key characteristics in prolonged hydrophilic drug release, but only when wetting is the rate-limiting step for the drug release. Combination of drugs showed beneficial effects by inhibiting the growth of all tested pathogenic bacterial strains important in periodontal diseases.

Electrospinning: An enabling nanotechnology platform for drug delivery and regenerative medicine

Electrospinning provides an enabling nanotechnology platform for generating a rich variety of novel structured materials in many biomedical applications including drug delivery, biosensing, tissue engineering, and regenerative medicine. In this review article, we begin with a thorough discussion on the method of producing 1D, 2D, and 3D electrospun nanofiber materials. In particular, we emphasize on how the 3D printing technology can contribute to the improvement of traditional electrospinning technology for the fabrication of 3D electrospun nanofiber materials as drug delivery devices/implants, scaffolds or living tissue constructs. We then highlight several notable examples of electrospun nanofiber materials in specific biomedical applications including cancer therapy, guiding cellular responses, engineering in vitro 3D tissue models, and tissue regeneration. Finally, we finish with conclusions and future perspectives of electrospun nanofiber materials for drug delivery and regenerative medicine.

Multifunctional Electrospun Nanofibers for Enhancing Localized Cancer Treatment

Localized cancer treatment is one of the most effective strategies in clinical destruction of solid tumors at early stages as it can minimize the side effects of cancer therapeutics. Electrospun nanofibers have been demonstrated as a promising implantable platform in localized cancer treatment, enabling the on-site delivery of therapeutic components and minimizing side effects to normal tissues. This Review discusses the recent cutting-edge research with regard to electrospun nanofibers used for various therapeutic approaches, including gene therapy, chemotherapy, photodynamic therapy, thermal therapy, and combination therapy, in enhancing localized cancer treatment. Furthermore, it extensively analyzes the current challenges and potential breakthroughs in utilizing this novel platform for clinical transition in localized cancer treatment.

Emerging Roles of Electrospun Nanofibers in Cancer Research

This article reviews the recent progress of electrospun nanofibers in cancer research. It begins with a brief introduction to the emerging potential of electrospun nanofibers in cancer research. Next, a number of recent advances on the important features of electrospun nanofibers critical for cancer research are discussed including the incorporation of drugs, control of release kinetics, orientation and alignment of nanofibers, and the fabrication of 3D nanofiber scaffolds. This article further highlights the applications of electrospun nanofibers in several areas of cancer research including local chemotherapy, combinatorial therapy, cancer detection, cancer cell capture, regulation of cancer cell behavior, construction of in vitro 3D cancer model, and engineering of bone microenvironment for cancer metastasis. This progress report concludes with remarks on the challenges and future directions for design, fabrication, and application of electrospun nanofibers in cancer diagnostics and therapeutics.

Simultaneous and controlled release of two different bioactive small molecules from nature inspired single material

Simultaneous and extended (over 6 months) release of two different bioactive small molecules from single polymeric material was successfully achieved through strategic use of metastable trapped air for the first time.

'Reactive' nano-complex coated medical cotton: a facile avenue for tailored release of small molecules

Controlled and sustained release of drug-like small molecules in an aqueous medium still remains a challenging problem due to rapid infiltration of liquid water in most reported drug release systems. However, internal-superhydrophobicity with an antifouling property extending beyond the surface of a material recently has been recognized as a potential avenue for sustained and extended release of drug-like small molecules. Sluggish removal of metastable trapped air in a superhyrophobic material provides a basis to achieve extended release of encapsulated small molecules. In this article, naturally abundant medical-cotton-extensively used in wound management including control of bleeding, absorbance of secretions and protecting wounds from contamination-is strategically exploited in tailoring (from rapid to extended) the release of small molecules by appropriate modulation of liquid water wettability. Modulation included bio-mimicked adhesive and non-adhesive superhydrophobicity of the medical cotton without erosion of any polymeric material. In this process, amine 'reactive' nano-complexes (RNC) were prepared by just mixing branched poly(ethylenimine) (BPEI) with dipentaerythritol pentaacrylate (5Acl) in ethanol with appropriate compositions. Then they were covalently immobilized on fibrous medical-cotton through a facile and robust 1,4-conjugated addition reaction. Residual acrylate moieties in the immobilized RNC provide an opportunity to tailor water wettability through strategic and appropriate post-chemical modification of RNC-coated medical cotton with a primary amine containing various small molecules. This medical-cotton with tunable wettability was exploited further to control the release rate of small molecules from rapid (<24 h) to sustained (>100 days) times. A volatile solvent induced transient and reversible switching of anti-fouling properties which allowed further varying the amount of post-loading small molecules into the medical cotton up to 2.36 wt% without compromising the embedded anti-wetting property. Thus, our current approach has immense potential to develop appropriate materials for a sustained and controlled release of small molecules from a clinically relevant substrate (i.e., medical-cotton) and may be useful in various bio-medical applications including improving wound management, preventing bacterial infections, better pain management, etc.

Possible role of nanocarriers in drug delivery against cervical cancer

Introduction: Cervical cancer is the second most common cancer and the largest cancer killer among women in most developing countries including India. Although, various drugs have been developed for cervical cancer, treatment with these drugs often results in a number of undesirable side effects, toxicity and multidrug resistance (MDR). Also, the outcomes for cervical cancer patients remain poor after surgery and chemo radiation. Methods: A literature search (for drugs and delivery systems against cervical cancer) was performed on PubMed and through Google. The present review discuss about various methods including its current conventional treatment with special reference to recent advances in delivery systems encapsulating various anticancer drugs and natural plant products for targeting towards cervical cancer. The role of photothermal therapy, gene therapy and radiation therapy against cervical cancer is also discussed. Results: Systemic/targeted drug delivery systems including liposomes, nanoparticles, hydrogels, dendrimers etc. and localized drug delivery systems like cervical patches, films, rings etc. are safer than the conventional chemotherapy which has further been proved by the several drug delivery systems undergoing clinical trials. Conclusion: Novel approaches for the aggressive treatment of cervical cancer will optimistically result in decreased side effects as well as toxicity, frequency of administration of existing drugs, to overcome MDR and to increase the survival rates.

Selective surface tension induced patterning on flexible textiles via click chemistry

A solid surface commonly forms two wetting modes by alternating the type of the liquids, i.e. wetting and nonwetting. Here we report that a textile can be programmed to exhibit three wetting modes by simply alternating the surface tension of the liquids, they are in turn, wetting, selective wetting and nonwetting. The hidden patterns are prepared via a combination of wet chemical etching and two-step UV-induced thiol-ene click chemistry to graft low-surface-tension thiols and high-surface-tension thiols, respectively, on the textile surface. The as-prepared flexible textiles possess the nonwetting and wetting properties of the high-surface-tension liquids, such as water and glycerol, and the low-surface-tension liquids, such as decane and ethanol, respectively. Furthermore, the selective wetting behavior can be revealed only if the surface tension of the liquids is within a narrow range of approximately 44.8 mN m^-1 to 28.1 mN m^-1, such as N,N-dimethylformamide and acetonitrile. In addition, the as-patterned textiles demonstrated high mechanical and chemical stability with long-term and repeated usage, which implies their high potential to act as novel encoded information carrier materials for flexible and textile-based devices.

A review of evolution of electrospun tissue engineering scaffold: From two dimensions to three dimensions

The potential of electrospinning process to fabricate ultrafine fibers as building blocks for tissue engineering scaffolds is well recognized. The scaffold construct produced by electrospinning process depends on the quality of the fibers. In electrospinning, material selection and parameter setting are among many factors that contribute to the quality of the ultrafine fibers, which eventually determine the performance of the tissue engineering scaffolds. The major challenge of conventional electrospun scaffolds is the nature of electrospinning process which can only produce two-dimensional electrospun mats, hence limiting their applications. Researchers have started to focus on overcoming this limitation by combining electrospinning with other techniques to fabricate three-dimensional scaffold constructs. This article reviews various polymeric materials and their composites/blends that have been successfully electrospun for tissue engineering scaffolds, their mechanical properties, and the various parameters settings that influence the fiber morphology. This review also highlights the secondary processes to electrospinning that have been used to develop three-dimensional tissue engineering scaffolds as well as the steps undertaken to overcome electrospinning limitations.