Electrospun, drug-enriched bioresorbable nonwovens based on poly(glycolide-ɛ-caprolactone) and poly(d,l-lactide-glycolide) for urological applications

Research progress, models and simulation of electrospinning technology: a review

In recent years, nanomaterials have aroused extensive research interest in the world's material science community. Electrospinning has the advantages of wide range of available raw materials, simple process, small fiber diameter and high porosity. Electrospinning as a nanomaterial preparation technology with obvious advantages has been studied, such as its influencing parameters, physical models and computer simulation. In this review, the influencing parameters, simulation and models of electrospinning technology are summarized. In addition, the progresses in applications of the technology in biomedicine, energy and catalysis are reported. This technology has many applications in many fields, such as electrospun polymers in various aspects of biomedical engineering. The latest achievements in recent years are summarized, and the existing problems and development trends are analyzed and discussed.

Electrospun paclitaxel delivery system based on PGCL/PLGA in local therapy combined with brachytherapy

The local administration of different drugs in anticancer therapy continue to attract attention. Thus, the idea of local delivery of cytostatics from nonwoven-structured polyesters seems to be highly desirable. It could reduce systemic drug levels and provide high local concentration of the chemotherapeutics at the tumor site and contribute to enhance the efficiency of the anticancer therapy. Poly(glycolide-ɛ-caprolactone) (PGCL) and poly(D,L-lactide-co-glycolide) (PLGA) synthesized with zirconium-based initiator have been used to prepare electrospun, drug-eluting patches since they possess very good fiber-forming ability. Well-known chemotherapeutic drug-paclitaxel has been loaded into fibrous structure as a model anticancer agent in order to obtain drug delivery systems for local administration. The drug dose in obtained nonwovens might be regulated by the thickness and total area of the implanted patches. Electrospinning of PGCL/PLGA blend allowed to obtain soft and flexible implantable materials. Flexibility has been important factor since it ensures convenient use when covering a tumor or filling a resection cavity. The effectiveness of designed nonwovens presented in the study has been tested in vivo on mouse model of breast cancer. The growth of the tumors was slowed down during in vivo study in comparison with drug-free nonwovens- The volume of the tumor was 40% lower. Drug-loaded electrospun systems implanted locally to the tumor site was further combined with brachytherapy which improved the effectiveness of the therapy in about 18%. Detailed analysis of the nonwovens before and during degradation process has been performed by means of Scanning Electron Microscopy, Differential Scanning Calorimetry, Nuclear Magnetic Resonance, Gel Permeation Chromatography, X-ray Diffraction. The molar mass changes of the nonwoven were quite rapid contrary to changes of comonomer unit content, thermal properties and morphology of the fiber.

Role of Electrospinning Parameters on Poly(Lactic-co-Glycolic Acid) and Poly(Caprolactone-co-Glycolic acid) Membranes

Poly(lactic-co-glycolic acid) (PLGA) and poly(caprolactone-co-glycolic acid) (PCLGA) solutions were electrospun into membranes with tailored fiber diameter of 1.8 μm. This particular fiber diameter was tuned depending on the used co-polymer by adjusting the electrospinning parameters that mainly influence the fiber diameter. The greatest setting of the fiber diameter was achieved by varying the polymer solution parameters (polymer concentration, solvents and solvents ratio). PLGA was adequately electrospun with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), whereas PCLGA required a polar solvent (such as chloroform) with a lower dielectric constant. Moreover, due to the amorphous morphology of PCLGA, pyridine as salt had to be added to the starting solution to increase its conductivity and make it electrospinnable. Indeed, the electrospinning of this co-polymer presents notable difficulties due to its amorphous structure. Interestingly, PCLGA, having a higher glycolic acid molar fraction than commonly electrospun co-polymers (caprolactone:glycolic acid ratio of 45:55 instead of 90:10), could be successfully electrospun, which has not been reported to date. To an accurate setting of fiber diameter, the voltage and the distance from needle to collector were varied. Finally, the study of the surface tension, conductivity and viscosity of the polymer solutions allowed to correlate these particular characteristics of the solutions with the electrospinning variables so that prior knowledge of them enables predicting the required processing conditions.