Effectiveness of Core-Shell Nanofibers Incorporating Amphotericin B by Solution Blow Spinning Against Leishmania and Candida Species

Nanotherapeutics for the delivery of antifungal drugs

The treatment of fungal infections is challenging with high death rates reported among immunocompromised patients. The currently available antifungals suffer from poor bioavailability and solubility, pharmacokinetics, and drug resistance, with limited cellular uptake. The clinical pipeline of new antifungals is dry. The incorporation of antifungal drugs into polymer-based nanocarriers to form nanotherapeutics is a promising approach to enhance the therapeutic outcomes of the available antifungal drugs. This review summarizes different polymer-based nanotherapeutics strategies that have been explored for the delivery of antifungals, resulting in enhanced therapeutic outcomes, such as improved pharmacokinetics, targeted/sustained delivery, prolonged drug circulation, retention of the drugs at the localized site of action, and overcoming drug resistance when compared with the free antifungal drugs.

Advances in Biomedical Applications of Solution Blow Spinning

In recent years, Solution Blow Spinning (SBS) has emerged as a new technology for the production of polymeric, nanocomposite, and ceramic materials in the form of nano and microfibers, with similar features to those achieved by other procedures. The advantages of SBS over other spinning methods are the fast generation of fibers and the simplicity of the experimental setup that opens up the possibility of their on-site production. While producing a large number of nanofibers in a short time is a crucial factor in large-scale manufacturing, in situ generation, for example, in the form of sprayable, multifunctional dressings, capable of releasing embedded active agents on wounded tissue, or their use in operating rooms to prevent hemostasis during surgical interventions, open a wide range of possibilities. The interest in this spinning technology is evident from the growing number of patents issued and articles published over the last few years. Our focus in this review is on the biomedicine-oriented applications of SBS for the production of nanofibers based on the collection of the most relevant scientific papers published to date. Drug delivery, 3D culturing, regenerative medicine, and fabrication of biosensors are some of the areas in which SBS has been explored, most frequently at the proof-of-concept level. The promising results obtained demonstrate the potential of this technology in the biomedical and pharmaceutical fields.

Nanomedicine-based strategies to improve treatment of cutaneous leishmaniasis

Nanomedicine strategies were first adapted and successfully translated to clinical application for diseases, such as cancer and diabetes. These strategies would no doubt benefit unmet diseases needs as in the case of leishmaniasis. The latter causes skin sores in the cutaneous form and affects internal organs in the visceral form. Treatment of cutaneous leishmaniasis (CL) aims at accelerating wound healing, reducing scarring and cosmetic morbidity, preventing parasite transmission and relapse. Unfortunately, available treatments show only suboptimal effectiveness and none of them were designed specifically for this disease condition. Tissue regeneration using nano-based devices coupled with drug delivery are currently being used in clinic to address diabetic wounds. Thus, in this review, we analyse the current treatment options and attempt to critically analyse the use of nanomedicine-based strategies to address CL wounds in view of achieving scarless wound healing, targeting secondary bacterial infection and lowering drug toxicity.

Controlled release and antiviral activity of acyclovir-loaded PLA/PEG nanofibers produced by solution blow spinning

Herpetic dermatitis and oral recurrent herpes (ORH) are among the most common human infections. Antiviral drugs such as acyclovir (ACV) are used in the standard treatment for ORH. Despite its therapeutic efficacy, ACV is continuously and repetitively administered in high doses. In this sense, the development of controlled release drug delivery systems such as core-shell fibers have a great potential in the treatment of ORH. In this work, poly(lactic acid)/poly(ethylene glycol) (PLA/PEG) fibers were produced by solution blow spinning (SBS) for the controlled release of ACV encapsulated in the core. PLA/PEG nanofibers containing four different blend ratios (100:0, 90:10, 80:20 and 70:30 wt%) without or with 10 wt% ACV were characterized by scanning electron microscopy (SEM), thermogravimetry (TG) and differential scanning calorimetry (DSC). The ACV release profile for 21 days was accessed by UV-Vis spectroscopy. Static water contact angles of the spun fiber mats were measured by the sessile drop method to evaluate fiber wettability upon contact with skin for transdermal release. Cytotoxicity and antiviral efficacy against Herpes simplex viruses (HSV-1) were evaluated using Vero cells. ACV addition did not impact on morphology, but slightly improved thermal stability of the fibers. Addition of hydrophilic PEG in PLA/PEG blends, however, increased drug release as confirmed by contact angle measurements and release profile. The in vitro tests showed the effectiveness of the drug delivery systems developed in reducing HSV-1 viral titer, which is related to the judicious combination of polymers used in the fibrous mats, in addition to not being cytotoxic to Vero cells. These results show the great potential of PLA/PEG solution blow-spun fibers in the controlled release of ACV to develop practical devices for the treatment of cold sores, while favoring the aesthetic appearance by covering them with a soft tissue patch (fibrous mats).

Enhanced In Vitro Wound Healing Using PVA/B-PEI Nanofiber Mats: A Promising Wound Therapeutic Agent against ESKAPE and Opportunistic Pathogens

Opportunistic skin pathogens and their resistance to pre-existing therapeutics are a challenge to normal physiological wound healing processes. Consistent development of antimicrobial agents is required to overcome the complications raised by antimicrobial resistance. An effective alternative proposed in recent research includes the use of antimicrobial nanoparticles or nanobiopolymers. Unfortunately, metallic nanoparticles that have been proven as antimicrobial agents also possess a certain level of toxicity. In this work, we demonstrate the use of a cationic polymer, branched polyethyleneimine (B-PEI), that has been electrospun to obtain a scaffold/fiber (B-PEI NF) mat resulting in a large surface area-to-volume ratio. SEM analysis revealed that the average diameter of the obtained fibers is 240 nm. The formation of nanoscaffold modulates the controlled release of the polymer from the matrix resulting in long-term effects. The antimicrobial and antibiofilm activity of the B-PEI nanofiber (B-PEI NF) was evaluated against ESKAPE pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and also against Candida albicans. Dose-dependent inhibition was observed for microbial growth and biofilm for all three test organisms, the minimum inhibitory concentration required for inhibiting P. aeruginosa, S. aureus, and C. albicans is 33.125, 26.5, and 19.875 μM, respectively, in 2 mL of bacterial/fungal broth. Crystal violet and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed significant reduction in biomass and cell viability of sessile cells, respectively, within the biofilm after treatment using B-PEI NFs. A B-PEI NF matrix promotes cell migration and wound healing processes by mimicking the extracellular matrix. In vitro wound healing studies showed a fivefold increase in cell migration and wound healing by B-PEI NFs (97% wound coverage in 17 h) when compared to B-PEI (15% wound coverage in 17 h). The in vitro wound healing assays confirmed the biocompatibility and better wound healing activity of B-PEI NF mats.

Fabrication of amphotericin B-loaded electrospun core-shell nanofibers as a novel dressing for superficial mycoses and cutaneous leishmaniasis

Amphotericin B (AmB) is an antifungal and antiparasitic agent that is the main drug used for the treatment of mycoses infections and leishmaniasis. However, its high toxicity and side effects are the main difficulties attributed to its application. In this study, to minimize its harmful effects, AmB-loaded core-shell nanofibers were fabricated, using polyvinyl alcohol, chitosan, and AmB as the core, and polyethylene oxide and gelatin as the shell-forming components. The nanofibers were characterized, using scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, tensile test, drug release, and MTT assay. The results showed that the prepared nanofibers were smooth and had a core-shell structure with almost no cytotoxicity against fibroblast cells and the release study suggested that the core-shell structure decreased the burst release. The disk diffusion assay revealed that the nanofibrous mats at different AmB concentrations exhibited significant activity against all the eight evaluated fungal species with the inhibition zones of 1.4-2.6 cm. The flow cytometry assay also showed that the prepared nanofibrous mat significantly killed Leishmania major promastigotes up to 84%. The obtained results indicated that this AmB-loaded nanofibrous system could be a suitable candidate for a topical drug delivery system for the treatment of both superficial mycoses and cutaneous leishmaniasis.