Biodegradable Nanofiber for Delivery of Immunomodulating Agent in the Treatment of Basal Cell Carcinoma

Novel Combination Treatment for Melanoma: FLASH Radiotherapy and Immunotherapy Delivered by a Radiopaque and Radiation Responsive Hydrogel

Immunotherapies have become the standard treatment for melanoma. To further improve patient responses, combinations of immunotherapies and radiotherapy (RT) are being studied, since radiotherapies can potentially provide additional immune stimulation, in addition to direct antitumor effects. FLASH-RT is a novel, ultrahigh dose rate, radiation delivery approach, with the potential of at least equivalent tumor control efficacy and reduced damage to healthy tissue. However, the effects of combining FLASH-RT and immunotherapy have not been extensively studied in melanoma. Toll-like receptor (TLR) agonists, such as imiquimod (IMQ), are potent immunostimulatory agents, although their utility is limited due to poor solubility and systemic side effects. We therefore developed a novel combination therapy for melanoma consisting of IMQ delivered to the tumor via a radiopaque and radiation responsive hydrogel combined with FLASH-RT. We found that FLASH was able to effectively stimulate IMQ release from the hydrogel. In addition, we found that the combination of FLASH and released IMQ resulted in synergistic melanoma cell killing in vitro. The combination therapy reduced tumor growth compared to controls, enhanced survival, and resulted in remarkable enhancements in certain tumor cytokine levels. CT imaging allowed the hydrogel to be monitored in vivo. In addition, no adverse effects of the treatment were observed. Overall, this IMQ-gel and FLASH-RT combination may have potential as an improved treatment for melanoma and indicates that the interactions of FLASH-RT and TLR agonists merit further study.

Shape-memory balloon offering simultaneous thermo/chemotherapies to improve anti-osteosarcoma efficacy

This paper proposes a shape-memory balloon (SMB) to improve bone cement injection efficiency and postoperative thermo/chemotherapy for bone tumors. The SMB consists of biodegradable poly(ε-caprolactone) (PCL), an anticancer drug (doxorubicin, DOX), and heat-generating magnetic nanoparticles (MNPs). The balloon shape is fabricated in a mold by crosslinking PCL macromonomers with DOX and MNPs. The mechanical properties and shape-transition temperature (approximately 40 °C) of the SMB are modulated by adjusting the molecular weight of PCL and the crosslinking density. This allows safe inflation at the affected site with a 400% expansion rate by simple blow molding. The expanded shape is temporarily memorized at 37 °C, and the computed tomography image shows that the bone cement is successfully injected without extra pressure or leakage. The SMB releases DOX for over 4 weeks, allowing a prolonged effect at the local site. The local dosing is constant as the medication is continuously released, demonstrating an ON-OFF switchable heating/cooling response to alternating magnetic field irradiation. In vitro cytotoxic studies have demonstrated that heat generation/drug release and only drug release from the balloon kill approximately 99% and 60% of human osteosarcoma cells, respectively. The proposed SMB is promising in postoperative local thermo/chemotherapy for bone tumors.

Micropatterned Fibrous Scaffold Produced by Using Template-Assisted Electrospinning Technique for Wound Healing Application

This paper describes the fabrication of a structural scaffold consisting of both randomly oriented nanofibers and triangular prism patterns on the scaffold surface using a combination technique of electrospinning and collector templates. The polycaprolactone (PCL) nanofibers were electrospun over a triangular prism pattern mold, which acted as a template. The deposited scaffold was removed from the template to produce a standalone structural scaffold of three-dimensional micropatterned nanofibers. The fabricated structural scaffold was compared with flat randomly oriented nanofibers based on in vitro and in vivo studies. The in vitro study indicated that the structural scaffold demonstrated higher fibroblast cell proliferation, cell elongation with a 13.48 ± 2.73 aspect ratio and 70% fibroblast cell orientation compared with flat random nanofibers. Among the treatment groups, the structural scaffold escalated the wound closure to 92.17% on day 14. Histological staining of the healed wound area demonstrated that the structural scaffold exhibited advanced epithelization of the epidermal layer accompanied by mild inflammation. The proliferated fibroblast cells and collagen fibers in the structural scaffold appeared denser and arranged more horizontally. These results determined the potential of micropatterned scaffolds for stimulating cell behavior and their application for wound healing.

A Current Review on Drug Loaded Nanofibers: Interesting and Valuable Platform for Skin Cancer Treatment

BACKGROUND

Nanofibers are used in topical medication for various skin diseases like wound healing, skin cancer and others. Non-melanoma skin cancers (NMSCs) are the most widely distributed diseases in the world, of which 99% of people are affected by either basal cell carcinomas (BCCs) or squamous cell carcinomas (SCCs) of the skin. Skin malignancy is caused by direct sun exposure and regular application of unsafe restorative items on the skin.

OBJECTIVE

This review presents the use of nanofibers in skin cancer treatment and advances made in skin cancer treatment.

METHODS

There are various methods used in the production of nanofibers such as bicomponent extrusion, phase separation, template synthesis, drawing, electrospinning, and others. Electrospinning is the most widely used technique for nanofiber fabrication. The nanofibers are produced in nanometer size range and mostly used in medication because of their low thickness, large surface area per unit mass and porosity. Nanofibers are also used as drug delivery system for sustaining the action of drugs or medicaments.

RESULTS

Nanofibers enhance the permeation and availability of those drugs having low bioavailability and low permeability. Nanofibers increase the sustainability of the drugs up to 10 days.

CONCLUSION

Skin cancer is the abnormal growth of skin cells in the body influencing people of all colours and skin. In this review paper, the definition and production techniques of nanofibers and drugs used in skin cancer treatment and the relation between skin cancer and nanofiber are illustrated in detail. With the help of different techniques and drugs, the risk of non-melanoma skin cancer is reduced. Lay Summary: The risk of skin cancer and other skin problems is increasing day by day. In a previous study we found that the nanofibers are less used as a topical delivery system. We have studied the nanofibers as a drug delivery system in the treatment of skin cancer by using different drugs. According our study nanofibers are most useful in skin drug delivery and if the nanofiber, are merging with other drug delivery system like nanoparticles, it may maximize the output of drug into skin. The significance of this study is, to explain all information about nanofibers in skin cancer.

A Diels-Alder polymer platform for thermally enhanced drug release toward efficient local cancer chemotherapy

We reports a novel thermally enhanced drug release system synthesized via a dynamic Diels-Alder (DA) reaction to develop chemotherapy for pancreatic cancer. The anticancer prodrug was designed by tethering gemcitabine (GEM) to poly(furfuryl methacrylate) (PFMA) via N-(3-maleimidopropionyloxy)succinimide as a linker by DA reaction (PFMA-L-GEM). The conversion rate of the DA reaction was found to be approximately 60% at room temperature for 120 h. The reversible deconstruction of the DA covalent bond in retro Diels-Alder (rDA) reaction was confirmed by proton nuclear magnetic resonance, and the reaction was significantly accelerated at 90 °C. A PFMA-LGEM film containing magnetic nanoparticles (MNPs) was prepared for thermally enhanced release of the drug via the rDA reaction. Drug release was initiated by heating MNPs by alternating magnetic field. This enables local heating within the film above the rDA reaction temperature while maintaining a constant surrounding medium temperature. The MNPs/PFMA-L-GEM film decreased the viability of pancreatic cancer cells by 49% over 24 h. Our results suggest that DA/rDA-based thermally enhanced drug release systems can serve as a local drug release platform and deliver the target drug within locally heated tissue, thereby improving the therapeutic efficiency and overcoming the side effects of conventional drugs used to treat pancreatic cancer.

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.

Combination of Electrospun Nanofiber Sheet Incorporating Methylcobalamin and PGA-Collagen Tube for Treatment of a Sciatic Nerve Defect in a Rat Model

BACKGROUND

For peripheral nerve defects, autografting is considered the therapeutic gold-standard treatment. However, this procedure leads to donor-site morbidity. While various artificial conduits have been recently developed, treatment outcome has been demonstrated to be poorer than that with autograft. In our previous study using a rat sciatic nerve crush injury model, we demonstrated that the delivery of electrospun nanofiber sheets incorporating methylcobalamin (MeCbl sheet) to the local site of a peripheral nerve injury promoted peripheral nerve regeneration. In this study, we examined the effects of combination therapy using an MeCbl sheet and a polyglycolic acid tube filled with collagen sponge (PGA-c) in a rat model of a 10-mm sciatic nerve defect.

METHODS

The rats were divided into 4 groups: (1) sham group (n = 10); (2) PGA-c group (n = 9), in which the gap was bridged using a PGA-c; (3) PGA-c/Sheet group (n = 8), in which the gap was bridged using a PGA-c wrapped in an MeCbl sheet; and (4) autograft group (n = 10), in which the gap was bridged using a reversed autograft. Motor and sensory function were evaluated, electrophysiological analysis was performed, and histomorphological findings were analyzed at 12 weeks postoperatively.

RESULTS

Compared with the PGA-c group, the PGA-c/Sheet group demonstrated significant improvements in the paw-withdrawal threshold expressed as a ratio relative to the contralateral side (mean difference [MD], -1.51; 95% confidence interval [CI], -2.64 to -0.38), terminal latency (MD, -0.86 ms; 95% CI, -1.56 to -0.16 ms), myelinated axon area (MD, 4.97%; 95% CI, 0.14% to 9.80%), proportion of myelinated axons (MD, 8.453%; 95% CI, 0.001% to 16.905%), and g-ratio (MD, -0.018; 95% CI, -0.035 to -0.001). No significant improvements were observed regarding motor function, electrophysiological findings with the exception of terminal latency, and axon numbers.

CONCLUSIONS

An MeCbl sheet in combination with a PGA-c significantly accelerated recovery with respect to sensory function, electrophysiology, and histomorphometry.

CLINICAL RELEVANCE

An MeCbl sheet may represent an effective therapeutic strategy for promoting regeneration across a nerve gap bridged with an artificial conduit.

Hyperthermia Nanofiber Platform Synergized by Sustained Release of Paclitaxel to Improve Antitumor Efficiency

Effective cancer therapy can be achieved by designing a smart nanofiber system with the combination of chemotherapy and hyperthermia. This study demonstrates the in vivo antitumor effect of a nanofiber mesh that can deliver heat and antitumor drug in a controlled manner. The mesh is composed of biodegradable poly(ε-caprolactone) (PCL) with paclitaxel (PTX) and magnetic nanoparticles (MNPs). The PCL mesh releases PTX slowly for at least 6 weeks when tested in vitro. The prolonged therapeutic effect is observed in vivo as a continuous release of medication from the mesh over an extended period of time compared with direct injection of PTX into the tumor site. In addition, the synergistic anticancer effect is achieved upon excitation of the mesh with an alternating magnetic field because the MNPs within the nanofiber generate localized heat which causes heat-induced cell killing as well as enhanced chemotherapeutic effect of PTX. Based on these results, the smart nanofiber system may be very promising for cancer therapeutics in the future and may provide knowledge for new development of localized drug delivery.

Fabrication of Water Absorbing Nanofiber Meshes toward an Efficient Removal of Excess Water from Kidney Failure Patients

Excellent water-absorbing nanofiber meshes were developed as a potential material for removing excess fluids from the blood of chronic renal failure patients toward a wearable blood purification system without requiring specialized equipment. The nanofiber meshes were successfully fabricated from poly(acrylic acid) (PAA) under various applied voltages by appropriately setting the electrospinning conditions. The electrospun PAA nanofibers were thermally crosslinked via heat treatment and then neutralized from their carboxylic acid form (PAA) to a sodium carboxylate form poly(sodium acrylate) (PSA). The PSA nanofiber meshes exhibited a specific surface area 393 times that of the PSA film. The PSA fiber meshes showed a much faster and higher swelling than its corresponding film, owing to the higher capillary forces from the fibers in addition to the water absorption of the PSA gel itself. The proposed PSA fibers have the potential to be utilized in a new approach to remove excess water from the bloodstream without requiring specialized equipment.

Shape-Memory Nanofiber Meshes with Programmable Cell Orientation

In this work we report the rational design of temperature-responsive nanofiber meshes with shape-memory properties. Meshes were fabricated by electrospinning poly(ε-caprolactone) (PCL)-based polyurethane with varying ratios of soft (PCL diol) and hard [hexamethylene diisocyanate (HDI)/1,4-butanediol (BD)] segments. By altering the PCL diol:HDI:BD molar ratio both shape-memory properties and mechanical properties could be readily turned and modulated. Though mechanical properties improved by increasing the hard to soft segment ratio, optimal shape-memory properties were obtained using a PCL/HDI/BD molar ratio of 1:4:3. Microscopically, the original nanofibrous structure could be deformed into and maintained in a temporary shape and later recover its original structure upon reheating. Even when deformed by 400%, a recovery rate of >89% was observed. Implementation of these shape memory nanofiber meshes as cell culture platforms revealed the unique ability to alter human mesenchymal stem cell alignment and orientation. Due to their biocompatible nature, temperature-responsivity, and ability to control cell alignment, we believe that these meshes may demonstrate great promise as biomedical applications.

Electrospun Poly(ε-caprolactone) Nanofibrous Mesh for Imiquimod Delivery in Melanoma Therapy

Drug delivery systems (DDS) are commonly employed to administer drug-loaded composites to their therapeutic targets both in vitro and in vivo. Thus, we herein report the study of imiquimod-poly(ε-caprolactone) (IMQ-PCL) nanofibrous meshes for application in melanoma therapy. The preparation route employed was based on the electrospinning technique, with the melanoma cells being cultured on electrospun nanofibrous meshes to study their biocompatibility. All parameters employed, including the flow rate and polymer solution concentration, were examined to gain an improved understanding of the factors influencing the diameter and morphology of the electrospun fibre. The optimised parameters were employed to produce 12 IMQ-PCL nanofibrous meshes with diameters ranging from 100 to 900 nm to the melanoma cell viability. The relationship between the fibrous diameter and the imiquimod release profile was also determined using UV-Vis spectroscopy. In addition, similar results were obtained for the simulated imiquimod release profile obtained by COMSOL Multiphysics®. The IMQ-PCL nanofibrous meshes were found to decrease cell viability by ≥50%, with the number of cells dropping by ~10% over 48 h. As the cell viability was affected by the release of imiquimod, we believe that IMQ-PCL nanofibrous meshes are a promising drug delivery system for application in melanoma therapy.

Electrospun nanofiber sheets incorporating methylcobalamin promote nerve regeneration and functional recovery in a rat sciatic nerve crush injury model

Peripheral nerve injury is one of common traumas. Although injured peripheral nerves have the capacity to regenerate, axon regeneration proceeds slowly and functional outcomes are often poor. Pharmacological enhancement of regeneration can play an important role in increasing functional recovery. In this study, we developed a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl), one of the active forms of vitamin B12 homologues, to deliver it enough locally to the peripheral nerve injury site. We evaluated whether local administration of MeCbl at the nerve injury site was effective in promoting nerve regeneration. Electrospun nanofiber sheets gradually released MeCbl for at least 8weeks when tested in vitro. There was no adverse effect of nanofiber sheets on function in vivo of the peripheral nervous system. Local implantation of nanofiber sheets incorporating MeCbl contributed to the recovery of the motor and sensory function, the recovery of nerve conduction velocity, and the promotion of myelination after sciatic nerve injury, without affecting plasma concentration of MeCbl.

STATEMENT OF SIGNIFICANCE

Methylcobalamin (MeCbl) is a vitamin B12 analog and we previously reported its effectiveness in axonal outgrowth of neurons and differentiation of Schwann cells both in vitro and in vivo. Here we estimated the effect of local administered MeCbl with an electrospun nanofiber sheet on peripheral nerve injury. Local administration of MeCbl promoted functional recovery in a rat sciatic nerve crush injury model. These sheets are useful for nerve injury in continuity differently from artificial nerve conduits, which are useful only for nerve defects. We believe that the findings of this study are relevant to the scope of your journal and will be of interest to its readership.

Inactivated Sendai Virus (HVJ-E) Immobilized Electrospun Nanofiber for Cancer Therapy

Inactivated Hemagglutinating Virus of Japan Envelope (HVJ-E) was immobilized on electrospun nanofibers of poly(ε-caprolactone) by layer-by-layer (LbL) assembly technique. The precursor LbL film was first constructed with poly-L-lysine and alginic acid via electrostatic interaction. Then the HVJ-E particles were immobilized on the cationic PLL outermost surface. The HVJ-E adsorption was confirmed by surface wettability test, scanning laser microscopy, scanning electron microscopy, and confocal laser microscopy. The immobilized HVJ-E particles were released from the nanofibers under physiological condition. In vitro cytotoxic assay demonstrated that the released HVJ-E from nanofibers induced cancer cell deaths. This surface immobilization technique is possible to perform on anti-cancer drug incorporated nanofibers that enables the fibers to show chemotherapy and immunotherapy simultaneously for an effective eradication of tumor cells in vivo.