Electrospun composite nanofibers containing nanoparticles for the programmable release of dual drugs

Cancer Treatment Using Nanofibers: A Review

Currently, the number of patients with cancer is expanding consistently because of a low quality of life. For this reason, the therapies used to treat cancer have received a lot of consideration from specialists. Numerous anticancer medications have been utilized to treat patients with cancer. However, the immediate utilization of anticancer medicines leads to unpleasant side effects for patients and there are many restrictions to applying these treatments. A number of polymers like cellulose, chitosan, Polyvinyl Alcohol (PVA), Polyacrylonitrile (PAN), peptides and Poly (hydroxy alkanoate) have good properties for the treatment of cancer, but the nanofibers-based target and controlled drug delivery system produced by the co-axial electrospinning technique have extraordinary properties like favorable mechanical characteristics, an excellent release profile, a high surface area, and a high sponginess and are harmless, bio-renewable, biofriendly, highly degradable, and can be produced very conveniently on an industrial scale. Thus, nanofibers produced through coaxial electrospinning can be designed to target specific cancer cells or tissues. By modifying the composition and properties of the nanofibers, researchers can control the release kinetics of the therapeutic agent and enhance its accumulation at the tumor site while minimizing systemic toxicity. The core-shell structure of coaxial electrospun nanofibers allows for a controlled and sustained release of therapeutic agents over time. This controlled release profile can improve the efficacy of cancer treatment by maintaining therapeutic drug concentrations within the tumor microenvironment for an extended period.

"Nano in Nano"-Incorporation of ZnO Nanoparticles into Cellulose Acetate-Poly(Ethylene Oxide) Composite Nanofibers Using Solution Blow Spinning

In this work, the preparation and characterization of composites from cellulose acetate (CA)-poly(ethylene oxide) (PEO) nanofibers (NFs) with incorporated zinc oxide nanoparticles (ZnO-NPs) using solution blow spinning (SBS) is reported. CA-PEO nanofibers were produced by spinning solution that contained a higher CA-to-PEO ratio and lower (equal) CA-to-PEO ratio. Nanoparticles were added to comprise 2.5% and 5% of the solution, calculated on the weight of the polymers. To have better control of the SBS processing conditions, characterization of the spinning suspensions is carried out, which reveals a decrease in viscosity (two- to eightfold) upon the addition of NPs. It is observed that this variation of viscosity does not significantly affect the mean diameters of nanofibers, but does affect the mode of the nanofibers' size distribution, whereby lower viscosity provides thinner fibers. FESEM-EDS confirms ZnO NP encapsulation into nanofibers, specifically into the CA component based on UV-vis studies, since the release of ZnO is not detected for up to 5 days in deionized water, despite the significant swelling of the material and accompanied dissolution of water-soluble PEO. Upon the dissolution of CA nanofibers into acetone, immediate release of ZnO is detected, both visually and by spectrometer. ATR-FTIR studies reveal interaction of ZnO with the CA component of composite nanofibers. As ZnO nanoparticles are known for their bioactivity, it can be concluded that these CA-PEO-ZnO composites are good candidates to be used in filtration membranes, with no loss of incorporated ZnO NPs or their release into an environment.

Selenium nanoparticles incorporated in nanofibers media eliminate H1N1 activity: a novel approach for virucidal antiviral and antibacterial respiratory mask

The consecutive viral infectious outbreaks impose severe complications on public health besides the economic burden which led to great interest in antiviral personal protective equipment (PPE). Nanofiber-based respiratory mask has been introduced as a significant barrier to eliminate the airborne transmission from aerosols toward reduction the viral infection spreading. Herein, selenium nanoparticles incorporated in polyamide 6 nanofibers coated on spunbond nonwoven were synthesized via electrospinning technique (PA6@SeNPs), with an average diameter of 180 ± 2 nm. The nanofiber-coated media were tested for 0.3 μm particulate filtration efficiency based on Standard NIOSH (42 CFR 84). PA6@SeNPs had a pressure drop of 45 ± 2 Pa and particulate filtration efficiency of more than 97.33 which is comparable to the N95 respiratory mask. The bacterial killing efficiency of these nanofibers was 91.25% and 16.67% against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. Furthermore, the virucidal antiviral test for H1N1 infected Madin-Darby Canine Kidney cells (MDCK) exhibited TCID50 of 108.13, 105.88, and 105.5 for 2, 10, and 120 min of exposure times in comparison with 108.5, 107.5, and 106.5 in PA6 nanofibers as control sample. MTT assay indicated excellent biocompatibility of electrospun PA6@SeNP nanofibers on L292 cells. These results propose the PA6@SeNP nanofibers have a high potential to be used as an efficient layer in respiratory masks for protection against respiratory pathogens.

Structural Control of Nanofibers According to Electrospinning Process Conditions and Their Applications

Nanofibers have gained much attention because of the large surface area they can provide. Thus, many fabrication methods that produce nanofiber materials have been proposed. Electrospinning is a spinning technique that can use an electric field to continuously and uniformly generate polymer and composite nanofibers. The structure of the electrospinning system can be modified, thus making changes to the structure, and also the alignment of nanofibers. Moreover, the nanofibers can also be treated, modifying the nanofiber structure. This paper thoroughly reviews the efforts to change the configuration of the electrospinning system and the effects of these configurations on the nanofibers. Excellent works in different fields of application that use electrospun nanofibers are also introduced. The studied materials functioned effectively in their application, thereby proving the potential for the future development of electrospinning nanofiber materials.

Ocular application of electrospun materials for drug delivery and cellular therapies

The constraints of delivering conventional drugs, biologics and cell-based therapeutics to target ocular sites necessitate the fabrication of novel drug delivery systems to treat diverse ocular diseases. Conventional ocular drug delivery approaches are prone to low bioavailability, poor penetration and degradation of therapeutics, including cell-based therapies, leading to the need for frequent topical applications or intraocular injections. However, owing to their exceptional structural properties, nanofibrous and microfibrous electrospun materials have gained significant interest in ocular drug delivery and biomaterial applications. This review covers the recent developments of electrospun fibers for the delivery of drugs, biologics, cells, growth factors and tissue regeneration in treating ocular diseases. The insights from this review can provide a thorough understanding of the selection of materials for the fabrication of nano- and/or micro-fibrous systems for ocular applications, with a particular interest in achieving controlled drug release and cell therapy. A detailed modality for fabricating different types of nano- and micro-fibers produced from electrospinning and factors influencing generation are also discussed.

Design and Fabrication of Electrospun PLA-Based Silica-Modified Composite Nanofibers with Antibacterial Properties for Perspective Wound Treatment

The aim of this study was to develop a novel amikacin (AMI) delivery system with prolonged release based on composite electrospun nanofibers of PLA supplemented with AMI-loaded Si nanoparticles of different morphology. The resultant materials were characterized in terms of their physical properties (scanning electron microscopy, Brunauer-Emmett-Teller analysis, thermogravimetric analysis, water contact angle). High-Performance Liquid Chromatography was used to determine the AMI content in the liquid fractions obtained from the release study. The results show that nanofibers of fumed silica exhibited an aggregated, highly porous structure, whereas nanofibers of mesoporous silica had a spherical morphology. Both silica nanoparticles had a significant effect on the hydrophilic properties of PLA nanofiber surfaces. The liquid fractions were investigated to gauge the encapsulation efficiency (EE) and loading efficiency (LE) of AMI, demonstrating 66% EE and 52% LE for nanofibers of fumed silica compared to nanofibers of mesoporous silica nanoparticles (52% EE and 12.7% LE). The antibacterial activity of the AMI-loaded nanofibers was determined by the Kirby-Bauer Method. These results demonstrated that the PLA-based silica nanofibers effectively enhanced the antibacterial properties against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae.

Formation of Hydrophilic Nanofibers from Nanostructural Design in the Co-Encapsulation of Celecoxib through Electrospinning

This study presents a method for a one-step co-encapsulation of PLGA nanoparticles in hydrophilic nanofibers. The aim is to effectively deliver the drug to the lesion site and achieve a longer release time. The celecoxib nanofiber membrane (Cel-NPs-NFs) was prepared by emulsion solvent evaporation and electrospinning with celecoxib as a model drug. By this method, nanodroplets of celecoxib PLGA are entrapped within polymer nanofibers during an electrospinning process. Moreover, Cel-NPs-NFs exhibited good mechanical strength and hydrophilicity, with a cumulative release of 67.74% for seven days, and the cell uptake at 0.5 h was 2.7 times higher than that of pure nanoparticles. Furthermore, pathological sections of the joint exhibited an apparent therapeutic effect on rat OA, and the drug was delivered effectively. According to the results, this solid matrix containing nanodroplets or nanoparticles could use hydrophilic materials as carriers to prolong drug release time.

Nanoparticles incorporated in nanofibers using electrospinning: A novel nano-in-nano delivery system

Nanofibers are cutting-edge drug delivery systems that are being utilised to treat a variety of ailments. Nanofibers are mostly woven by electrospinning techniques that are majorly used in drug delivery, wound dressing, tissue engineering, sensors, etc. They have several limitations that can be addressed by developing nano-in-nano delivery techniques. Nanoparticles are incorporated into nanofibers in these nano-in-nano systems. They offer a lot of benefits over other nanosystems, including the ability to shield drugs from physical deterioration, the ability to provide prolonged drug release, high surface area to volume ratio, increased drug loading capacity and the potential to be employed in critical conditions such as cancer. These nanoparticles can be encapsulated, entrapped, or adsorbed onto nanofibers in a variety of ways. To include nanosystems into nanofibers, a variety of materials and different kinds of nanoparticles can be used. The present review gives an insight to the applications of nano - in - nano drug delivery system for different diseases/disorders. The review also brings forward the current state of these novel delivery systems along with future perspectives.

Naproxen release behaviour from graphene oxide/cellulose acetate composite nanofibers

The present study investigated the effect of graphene oxide in cellulose acetate-based composite nanofibers on the transdermal delivery of naproxen. The composite nanofibers were successfully produced via the electrospinning process by directly mixing cellulose acetate, graphene oxide, and naproxen solution with varied compositions. The formation of the nanofibers was confirmed by electron microscopy and other characterization techniques to prove the existence of graphene oxide and naproxen itself. Surprisingly, graphene oxide encourages the production of nanofibers with smaller average diameter, higher conductivity, higher mechanical strength, and higher naproxen release from the cellulose acetate nanofibers. Once combined with naproxen, the composite nanofiber exhibited antibacterial activity with an inhibitory zone of 9.15 mm. The cytotoxicity evaluation also showed that the addition of naproxen increased the death of HeLa cells with a CC50 of up to 29.33 μg mL-1. The kinetic model of naproxen release follows the Korsmeyer-Peppas and Higuchi models with acceleration at neutral pH. These results are promising for further applications for wound healing purposes.

A multifunctional, one-step gas foaming strategy for antimicrobial silver nanoparticle-decorated 3D cellulose nanofiber scaffolds

Creating nanoparticle-decorated nanofibers in a single step can greatly speed up and scale up the production of scaffolds for various applications. In this study, we report a facile multifunctional method for the simultaneous foaming and synthesis of silver nanoparticles-covered three-dimensional cellulose using sodium borohydride (NaBH4). The physicochemical properties of the 3D cellulose-Ag scaffold were evaluated and compared to 2D CA membranes, including morphology (porous 3D vs flat 2D), mechanical properties (22.72 vs <13 MPa Young's modulus), antibacterial effect (27 vs 0 mm zone of inhibition), and biocompatibility. The findings suggest that our method enables the scaffold to be easily manufactured-indicating it can be used to scale-up manufacturing processes-with high bioactivity, antibacterial effect, and biocompatibility, showing potential as a 3D structure production method for tissue engineering and other relevant applications.

Electrospun polyvinyl-alcohol/gum arabic nanofibers: Biomimetic platform for in vitro cell growth and cancer nanomedicine delivery

The design of powerful in vitro cell culture platforms to support precision medicine can contribute to predict therapeutic success of cancer patients. Electrospun nanofibers applied to cell culture can mimic extracellular matrix and improve in vitro cell behavior. Here, we describe biocompatible blended polyvinyl-alcohol (PVA)/gum arabic (GA) extracellular matrix (ECM)-like nanofibers for in vitro cell cultures capable of delivering nanocomposite for desired biomedical application. Therefore, PVA/GA ECM-like electrospun nanofibers were developed and characterized. Heat treatment was used to crosslink the nanofibers and biocompatibility was evaluated, which demonstrated the ability of developed platform to provide a cell culture-friendly environment. Previous work demonstrated that GA-gold nanoparticles (GA-AuNPs) in non-cytotoxic concentrations can reduce key metastatic cellular events such as invasion and colony formation of metastatic melanoma cells. Thus, crosslinked nanofibers were functionalized with GA-AuNPs and its cellular delivery was evaluated. GA-AuNPs were efficiently adsorbed onto the PVA/GA nanofibers surface and the system effectively delivered the nanocomposites to metastatic melanoma cells. In conclusion, the described biocompatible system could be prospected as a valuable in vitro tool for precision medicine.

Mucoadhesive Electrospun Fibre-Based Technologies for Oral Medicine

Oral disease greatly affects quality of life, as the mouth is required for a wide range of activities including speech, food and liquid consumption. Treatment of oral disease is greatly limited by the dose forms that are currently available, which suffer from short contact times, poor site specificity, and sensitivity to mechanical stimulation. Mucoadhesive devices prepared using electrospinning offer the potential to address these challenges by allowing unidirectional site-specific drug delivery through intimate contact with the mucosa and with high surface areas to facilitate drug release. This review will discuss the range of electrospun mucoadhesive devices that have recently been reported to address oral inflammatory diseases, pain relief, and infections, as well as new treatments that are likely to be enabled by this technology in the future.

Colored Polymeric Nanofiber Loaded with Minoxidil Sulphate as Beauty Coverage and Restoring Hair Loss

Polymeric nanofibers fabricated by electrospinning either blank (PVA) or loaded with minoxidil sulphate have yielded optimum fibers with an average diameter 273 nm, and 511 nm, respectively. Thermal analysis of nanofibers indicated no chemical interaction. The NMR spectrum confirmed stability of nanofiber as there were no interactions between functional groups. Prepared nanofibers showed a 47.4% encapsulation efficiency and 73% yield. In vitro drug release of minoxidil sulphate from nanofiber exhibited an initial burst release followed by a slower release pattern. Stability studies revealed that minoxidil nanofiber was stable if stored at room temperature and protected from light with only loss of 9.6% of its nominal concentration within 6 months. As a result, the prepared solid/colored formula serves as an ideal formulation for such instable drug in liquid formula taking the advantage of the attractiveness of beauty colored coverage, and the simple, and non-tousled application.

Characterization of polyherbal-incorporated polycaprolactone nanofibrous mat for biomedical applications

The polyherbal-loaded polycaprolactone nanofibrous mat was prepared by electrospinning technique, and physical and chemical characteristics of nanofibrous mats were studied using scanning electron microscopy, x-ray diffraction, thermogravimetric analyzer, and Fourier transform infrared spectroscopy. The presence of various phytochemicals in the crude monoherbal and polyherbal extracts was analyzed. The antimicrobial activity and biocompatibility of the polyherbal-loaded nanofibrous mats were studied. The drug release pattern of the polyherbal-loaded nanofibrous mats was studied at different time intervals. The 5% drug-loaded nanofibrous mat shows higher sustainable drug release rate than 1% and 3% drug-loaded nanofibrous mats. The cell viability was found to be 98.91%, 98.77%, 98.5%, and 98.22% for polycaprolactone and 1%, 3%, and 5% for polyherbal-loaded nanofibrous mats, respectively.

Polyacrylonitrile (PAN) nanofibres spun with copper nanoparticles: an anti-Escherichia coli membrane for water treatment

Copper nanoparticles (CNPs) were mixed with polyacrylonitrile (PAN) and electrospun into nanofibres (CuPAN nanofibres). PAN nanofibres containing 1.0, 3.0 and 5.0% copper (w/v) displayed beads-on-string morphology with protrusions of copper particles. The diameter of the CuPAN nanofibres differed according to the copper content, ranging from 386 nm (1.0%, w/v, copper) to 922 nm (5.0%, w/v, copper). No chemical interaction of copper with PAN was observed when studied with X-ray diffraction, ATR-FTIR (attenuated total reflection-Fourier transform infrared) spectroscopy and TGA (thermogravimetric analysis). None of the CuPAN nanofibres showed signs of degradation after 7 days in water. Bacteria suspended in random mobility buffer and filtered through a 3% CuPAN nanofibre membrane (25 mm diameter, 75-80 μm thickness), at a filtration rate of 20 ml min^-1, reduced the cell numbers of enterotoxigenic Escherichia coli (ETEC) from 3.3 × to 2.1 × 10⁶ cfu ml^-1 and methicillin-resistant Staphylococcus aureus (MRSA) from 1.2 × 10 to 1.3 × 10³ cfu ml^-1. Membranes produced with 1.0, 3.0 and 5.0% (w/v) CuPAN inhibited the growth of enteroaggregative E. coli (EAEC), enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), ETEC and MRSA, as shown with LIVE/DEAD™ BacLight™ staining. Real-time bactericidal activity of CuPAN membranes was recorded by staining the cells with SYTO 9 and PI, followed by flow cytometry. Filter membranes made from CuPAN fibres may be used to reduce pathogenic E. coli cell numbers in potable water.

Nanoparticle-releasing nanofiber composites for enhanced in vivo vaginal retention

Current approaches for topical vaginal administration of nanoparticles result in poor retention and extensive leakage. To overcome these challenges, we developed a nanoparticle-releasing nanofiber delivery platform and evaluated its ability to improve nanoparticle retention in a murine model. We individually tailored two components of this drug delivery system for optimal interaction with mucus, designing (1) mucoadhesive fibers for better retention in the vaginal tract, and (2) PEGylated nanoparticles that diffuse quickly through mucus. We hypothesized that this novel dual-functioning (mucoadhesive/mucus-penetrating) composite material would provide enhanced retention of nanoparticles in the vaginal mucosa. Equivalent doses of fluorescent nanoparticles were vaginally administered to mice in either water (aqueous suspension) or fiber composites, and fluorescent content was quantified in cervicovaginal mucus and vaginal tissue at time points from 24 h to 7d. We also fabricated composite fibers containing etravirine-loaded nanoparticles and evaluated the pharmacokinetics over 7d. We found that our composite materials provided approximately 30-fold greater retention of nanoparticles in the reproductive tract at 24 h compared to aqueous suspensions. Compared to nanoparticles in aqueous suspension, the nanoparticles in fiber composites exhibited sustained and higher etravirine concentrations after 24 h and up to 7d, demonstrating the capabilities of this new delivery platform to sustain nanoparticle release out to 3d and drug retention out to one week after a single administration. This is the first report of nanoparticle-releasing fibers for vaginal drug delivery, as well as the first study of a single delivery system that combines two components uniquely engineered for complementary interactions with mucus.

G-CSF loaded nanofiber/nanoparticle composite coated with collagen promotes wound healing in vivo

Sustained release of functional growth factors can be considered as a beneficial methodology for wound healing. In this study, recombinant human granulocyte colony-stimulating factor (G-CSF)-loaded chitosan nanoparticles were incorporated in Poly(ε-caprolactone) (PCL) nanofibers, followed by surface coating with collagen type I. Physical and mechanical properties of the PCL nanofibers containing G-CSF loaded chitosan nanoparticles PCL/NP(G-CSF) and in vivo performance for wound healing were investigated. G-CSF structural stability was evaluated through SDS_PAGE, reversed phase (RP) HPLC and size-exclusion chromatography, as well as circular dichroism. Nanofiber/nanoparticle composite scaffold was demonstrated to have appropriate mechanical properties as a wound dresser and a sustained release of functional G-CSF. The PCL/NP(G-CSF) scaffold showed a suitable proliferation and well-adherent morphology of stem cells. In vivo study and histopathological evaluation outcome revealed that skin regeneration was dramatically accelerated under PCL/NP(G-CSF) as compared with control groups. Superior fibroblast maturation, enhanced collagen deposition and minimum inflammatory cells were also the beneficial properties of PCL/NP(G-CSF) over the commercial dressing. The synergistic effect of extracellular matrix-mimicking nanofibrous membrane and G-CSF could develop a suitable supportive substrate in order to extensive utilization for the healing of skin wounds. © 2017 Wiley Periodicals Inc. J Biomed Mater Res Part A: 105A: 2830-2842, 2017.

Fabrication of Core-Shell PEI/pBMP2-PLGA Electrospun Scaffold for Gene Delivery to Periodontal Ligament Stem Cells

Bone tissue engineering is the most promising technology for enhancing bone regeneration. Scaffolds loaded with osteogenic factors improve the therapeutic effect. In this study, the bioactive PEI (polyethylenimine)/pBMP2- (bone morphogenetic protein-2 plasmid-) PLGA (poly(D, L-lactic-co-glycolic acid)) core-shell scaffolds were prepared using coaxial electrospinning for a controlled gene delivery to hPDLSCs (human periodontal ligament stem cells). The pBMP2 was encapsulated in the PEI phase as a core and PLGA was employed to control pBMP2 release as a shell. First, the scaffold characterization and mechanical properties were evaluated. Then the gene release behavior was analyzed. Our results showed that pBMP2 was released at high levels in the first few days, with a continuous release behavior in the next 28 days. At the same time, PEI/pBMP2 showed high transfection efficiency. Moreover, the core-shell electrospun scaffold showed BMP2 expression for a much longer time (more than 28 days) compared with the single axial electrospun scaffold, as evaluated by qRT-PCR and western blot after culturing with hPDLSCs. These results suggested that the core-shell PEI/pBMP2-PLGA scaffold fabricated by coaxial electrospinning had a good gene release behavior and showed a prolonged expression time with a high transfection efficiency.

Nanocontainers in and onto Nanofibers

Hierarchical structure is a key feature explaining the superior properties of many materials in nature. Fibers usually serve in textiles, for structural reinforcement, or as support for other materials, whereas spherical micro- and nanoobjects can be either highly functional or also used as fillers to reinforce structure materials. Combining nanocontainers with fibers in one single object has been used to increase the functionality of fibers, for example, antibacterial and thermoregulation, when the advantageous properties given by the encapsulated materials inside the containers are transferred to the fibers. Herein we focus our discussion on how the hierarchical structure composed of nanocontainers in nanofibers yields materials displaying advantages of both types of materials and sometimes synergetical effects. Such materials can be produced by first carefully designing nanocontainers with defined morphology and chemistry and subsequently electrospinning them to fabricate nanofibers. This method, called colloid-electrospinning, allows for marrying the properties of nanocontainers and nanofibers. The obtained fibers could be successfully applied in different fields such as catalysis, optics, energy conversion and production, and biomedicine. The miniemulsion process is a convenient approach for the encapsulation of hydrophobic or hydrophilic payloads in nanocontainers. These nanocontainers can be embedded in fibers by the colloid-electrospinning technique. The combination of nanocontainers with nanofibers by colloid-electrospinning has several advantages. (1) The fiber matrix serves as support for the embedded nanocontainers. For example, through combining catalysts nanoparticles with fiber networks, the catalysts can be easily separated from the reaction media and handled visually. This combination is beneficial for the reuse of the catalyst and the purification of products. (2) Electrospun nanofibers containing nanocontainers offer the active agents inside the nanocontainers a double protection by both the fiber matrix and the nanocontainers. Since the polymer of the fibers and the polymer of the nanocontainers have usually opposite polarities, the encapsulated substance, for example, catalysts, dyes, or drugs, can be protected against a large variety of environmental influences. (3) Electrospun nanofibers exhibit unique advantages for tissue engineering and drug delivery that are a structural similarity to the extracellular matrix of biological tissues, large specific surface area, high and interconnected porosity which enhances cell adhesion, proliferation, drug loading, and mass transfer properties, as well as the flexibility in selecting the raw materials. Moreover, the nanocontainer-in-nanofiber structure allows multidrug loading and programmable release of each drug, which are very important to achieve synergistic effects in tissue engineering and disease therapy. The advantages offered by these materials encourage us to further understand the relationship between colloidal properties and fibers, to predict the morphology and properties of the fibers obtained by colloid-electrospinning, and to explore new possible combination of properties offered by nanoparticles and nanofibers.

Advancing Tissue Engineering: A Tale of Nano-, Micro-, and Macroscale Integration

Tissue engineering has the potential to revolutionize the health care industry. Delivering on this promise requires the generation of efficient, controllable and predictable implants. The integration of nano- and microtechnologies into macroscale regenerative biomaterials plays an essential role in the generation of such implants, by enabling spatiotemporal control of the cellular microenvironment. Here we review the role, function and progress of a wide range of nano- and microtechnologies that are driving the advancements in the field of tissue engineering.

Antimetastasis and antitumor efficacy promoted by sequential release of vascular disrupting and chemotherapeutic agents from electrospun fibers

The vasculature in tumor microenvironment plays important roles in the tumor growth and metastasis, and the combination of vascular disrupting agents with chemotherapeutic drugs should be effective in inhibiting tumor progression. But the dosing schedules are essential to achieve a balance between vascular collapse and intratumoral uptake of chemotherapeutic agents. In the current study, emulsion and blend electrospinning were used to create compartmental fibers accommodating both combretastatin A-4 (CA4) and hydroxycamptothecin (HCPT). The release durations of CA4 and HCPT were modulated through the structure of fibers for dual drug loadings and the inoculation of 2-hydroxypropyl-β-cyclodextrin in fiber matrices. Under a noncontact cell coculture in Transwell, the sequential release of CA4 and HCPT indicated a sequential killing of endothelial and tumor cells. In an orthotopic breast tumor model, all the CA4/HCPT-loaded fibers showed superior antitumor efficacy and higher survival rate than fibers with loaded individual drug. Compared with fibrous mats with infiltrated free CA4 and fibers with extended release of CA4 for over 30 days, fibers with sustained release of CA4 for 3-7 days from CA4/HCPT-loaded fibers resulted in the most significant antitumor efficacy, tumor vasculature destruction, and the least tumor metastasis to lungs. A judicious selection of CA4 release durations in the combination therapy should be essential to enhance the tumor suppression efficacy and antimetastasis activity.

Multiple drug-loaded electrospun PLGA/gelatin composite nanofibers encapsulated with mesoporous ZnO nanospheres for potential postsurgical cancer treatment

The novel PLGA/GE fibers encapsulated with DOX@mZnO were successfully fabricated, which enabled the delivery of two drugs with distinct rates.

Novel controlled drug delivery system for multiple drugs based on electrospun nanofibers containing nanomicelles

This research described a novel composite electrospun nanofibers, which were consisted of MPEG-b-PLA micelles, chitosan, and PEO, realizing controlled release of both hydrophobic and hydrophilic drugs. 5-FU and Cefradine used as model drugs were successfully loaded in the nanofibers. The in vitro studies showed there was a low initial burst release of 5-FU from micelles-loaded nanofibers, and the final release proportion was about 91.4% after continually releasing for 109 h. In vitro cytotoxicity studies revealed that 5-FU-loaded nanofibers restrained HepG-2 cells efficiently, and the cell viability was 45.9% after three days of cultivation in solutions containing micelles-loaded nanofibers with 21.6 μg 5-FU. All results suggested that micelles-loaded nanofibers with two kinds of drugs can be used as an effective controlled drug delivery vehicle and may have a bright future in cancer chemotherapy or clinical treatments.