Search

Wound dressings made from natural polymers are an important aspect of biomaterials. Protein-based materials are less likely to instigate an immunogenic response and have the capacity to degrade in vivo, also without triggering an inflammatory response. Therefore, gelatin (GEL) was chosen and combined with bacterial cellulose (BC) to produce nanofibres and the potential of an all-natural polymer construct was determined. GEL and BC were successfully electrospun with metformin (Met) and glybenclamide (Gb) using a portable, point of need electrospinning set up. The virgin fibre group exhibited a significant effect on the proliferation of L929 (mouse fibroblast) cells but all fibre samples can safely be applied on wound site without risk of cytotoxicity. According to the results obtained by animal tests, the GEL-BC-Gb group showed better recovery than the GEL-BC-Met group. Diabetic wounds treated with GEL-BC-Met were characterized by moderate re-epithelialization and partially organized granulation tissue. Moderate to complete re-epithelialization and well-formed granulation tissue were observed in diabetic wounds treated with GEL-BC-Gb. The histologic scores obtained on day 14 confirmed that the GEL-BC-Gb group played a stronger wound-healing role compared to the GEL-BC-Met group. The highest decrease of TNF-alpha level was observed in the GEL-BC-Gb group at the end of the experiment but there is no significant difference between drug-loaded fibre groups. Therefore, topical administration of ma and Gb in a sustained release form has a high potential for diabetic wound healing with high bioavailability and fewer systemic side effects but Gb showed better improvement according to the results of the animal tests.

Progesterone-loaded poly(lactic) acid fibrous polymeric patches were produced using electrospinning and pressurized gyration for infra-vaginal application to prevent preterm birth. The patches were intravaginally inserted into rats in the final week of their pregnancy, equivalent to the third trimester of human pregnancy. Maintenance tocolysis with progesterone-loaded patches was elucidated by recording the contractile response of uterine smooth muscle to noradrenaline in pregnant rats. Both progesterone-loaded patches indicated similar results from release and thermal studies, however, patches obtained by electrospinning had smaller average diameters and more uniform dispersion compared to pressurized gyration. Patches obtained by pressurized gyration had better results in production yield and tensile strength than electrospinning; thereby pressurized gyration is better suited for scaled-up production. The patches did not affect cell attachment, viability, and proliferation on Vero cells negatively. Consequently, progesterone-loaded patches are a novel and successful treatment strategy for preventing preterm birth.

A composite nanofiber composed of three polymers, namely polyvinyl alcohol/polyvinyl pyrrolidone/polyethylene oxide, is produced. The experiments are constructed using three design of experiment techniques, Taguchi L-9, Taguchi L-27, and Screening method. The experiments are verified using the analysis of variance (ANOVA) method and later a mathematical model is developed using the regression method. The impact of electrospun processing parameters, namely applied voltage, flow rate, and working distance, on nanofibers' diameter is measured. The working distance is a significant factor in controlling the size of the fiber diameter, while the applied voltage has the lowest effect on it. As a result of the regression equation, a Genetic algorithm is used to find the optimum variables for the required fiber diameter, which is 156 nm for flow rate = 0.001 mL h(-1), voltage = 30 kV, and distance = 200 mm with a 3% difference from the experimental fiber diameter.

Details of fibre diameter measurements as a function of process control parameters

In order to provide more effective treatment strategies for the rapid healing of diabetic wounds, novel therapeutic approaches need to be developed. The therapeutic potential of peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist pioglitazone hydrochloride (PHR) in two different release kinetic scenarios, burst release and sustained release, were investigated and compared with in vitro and in vivo tests as potential wound healing dressings. PHR-loaded fibrous mats were successfully fabricated using polyvinyl pyrrolidone and polycaprolactone by scalable pressurized gyration. The results indicated that PHR-loaded fibrous mats expedited diabetic wound healing in type-1 diabetic rats and did not show any cytotoxic effect on NIH/3T3 (mouse embryo fibroblast) cells, albeit with different release kinetics and efficacies. The wound healing effects of fibrous mats are presented with histological and biochemical evaluations. PHR-loaded fibrous mats improved neutrophil infiltration, oedema, and inflammation and increased epidermal regeneration and fibroblast proliferation but the formation of hair follicles and completely improved oedema were observed only in the sustained release form. Thus, topical administration of PPAR-γ agonist in sustained release form has high potential for the treatment of diabetic wounds in inflammatory and proliferative phases of healing with high bioavailability and fewer systemic side effects.

The fabrication of polymeric micro/nanofibers is gaining attention due to their use in an array of applications including tissue engineering scaffolds, nanosensors, and fiber-reinforced composites. Despite their versatile nature, polymeric fibers are widely underutilized due to the lack of reliable, large-scale production techniques. Upon the discovery of centrifugal spinning and, recently, pressurized gyration techniques, new research directions have emerged. Here, we report a comprehensive study detailing the optimal conditions to significantly improve the morphology, homogeneity, and yield of fibers of varying diameters. A series of polymeric fibers was created using a 21 wt.% solution of polyethylene oxide in distilled water and the fluid behavior was monitored inside a transparent reservoir using a high-speed camera. Fabrication of the fibers took less than 1 s. Using centrifugal spinning, we studied the formation of the fibers at three different rotational speeds, and for pressurized gyration, one rotational speed was studied with three different nitrogen gas pressures. Using the pressurized gyration technique at a gas pressure of 0.3 MPa, there was significant improvement in the production yield of the fibers. We found a strong correlation between the variation of pressure and the rate of the solution leaving the reservoir with the improved morphology of the fibers. The use of reduced power techniques, like centrifugal spinning and pressured gyration, to yield high-quality nonwoven nanofibers and microfibers in large quantities is important due to their use in rapidly expanding markets. (C) 2019 Author(s).

(a) Contact angle analysis machine with KRÜSS DSA10 instrument and a high-speed camera. (b) Photographic image showing the water contact angle θ on untreated PEEK surface. Scale bar: 2 mm. The solvent is deionised water at 22 ˚C. The average measurement was found to be 77.6±0.3˚.

Figure S1: (a) The process of producing microbubbles using a microfluidic V-junction. (b) Optical micrograph of the alginate microbubbles collected in calcium chloride and their changes during time laps immediately after collection (zero time).; Figure S2: The relative proliferation of primary leukaemia cells from AML patients (n=3) in foam-based scaffold (3D) compared to 2D is shown. The experiment was done in triplicate and shows higher proliferation of the cells in (3D) compared to 2D culture (p value: 0.005).; Figure S3: Enhanced myelomonocytic differentiation of blasts from an AML patient in 3D compared to 2D culture. The myeloblasts were further depleted (down to 50%) in CD34+ marker (red dots) after 3 days of culture in 3D compared to 2D.; Table S1: This table shows the percentage for various myeloid markers at day 0 and at 72 hours in 2D and 3D cultures for the samples shown in figure 3.; Figure S4: This figure shows the statistical differences between 2D and 3D cultures at 72 hours for the patients from figure 3.

Itraconazole is widely used as an anti-fungal drug to treat infections. However, its poor aqueous solubility results in low bioavailability. The aim of the present study was to improve the drug release profile by preparing surface itraconazole adsorbed polymethylsilsesquioxane (PMSQ) nanospheres using a V-junction microfluidic (VJM) device. In order to generate nanospheres with rough surface, the process flow rate of perfluorohexane (PFH) was set between 50 and 300μlmin−1 while the flow rate of PMSQ and itraconazole solution were constant at 300μlmin−1. Variations in the PFH flow rate enable the controlled size generation of nanospheres. PMSQ nanospheres adsorbing itraconazole were characterized by SEM, FTIR and Zetasizer. The release of itraconazole from PMSQ nanosphere surface was measured using UV spectroscopy. Nanosphere formulations with a range of sphere size (120, 320 and 800nm diameter) were generated and drug release was studied. 120nm itraconazole coated PMSQ nanospheres were found to present highest drug encapsulation efficiency and 13% drug loading in a more reproducible manner compared to 320nm and 800nm sized nanosphere formulations. Moreover, 120nm itraconazole coated PMSQ nanospheres (encapsulation efficiency: 88%) showed higher encapsulation efficiency compared to 320nm (encapsulation efficiency: 74%) and 800nm (encapsulation efficiency: 62%) sized nanosphere formulations. The itraconazole coated PMSQ nanospheres were prepared continuously at the rate of 2.6×106 per minute via VJM device. Overall the VJM device enabled the preparation of monodisperse surface itraconazole adsorbed nanospheres with controlled in vitro drug release profile.

Progesterone-loaded poly(lactic) acid fibrous polymeric patches were produced using electrospinning and pressurized gyration for intra-vaginal application to prevent preterm birth. The patches were intravaginally inserted into rats in the final week of their pregnancy, equivalent to the third trimester of human pregnancy. Maintenance tocolysis with progesterone-loaded patches was elucidated by recording the contractile response of uterine smooth muscle to noradrenaline in pregnant rats. Both progesterone-loaded patches indicated similar results from release and thermal studies, however, patches obtained by electrospinning had smaller average diameters and more uniform dispersion compared to pressurized gyration. Patches obtained by pressurized gyration had better results in production yield and tensile strength than electrospinning; thereby pressurized gyration is better suited for scaled-up production. The patches did not affect cell attachment, viability, and proliferation on Vero cells negatively. Consequently, progesterone-loaded patches are a novel and successful treatment strategy for preventing preterm birth.

The fabrication of polymeric micro/nanofibers is gaining attention due to their use in an array of applications including tissue engineering scaffolds, nanosensors, and fiber-reinforced composites. Despite their versatile nature, polymeric fibers are widely underutilized due to the lack of reliable, large-scale production techniques. Upon the discovery of centrifugal spinning and, recently, pressurized gyration techniques, new research directions have emerged. Here, we report a comprehensive study detailing the optimal conditions to significantly improve the morphology, homogeneity, and yield of fibers of varying diameters. A series of polymeric fibers was created using a 21 wt.% solution of polyethylene oxide in distilled water and the fluid behavior was monitored inside a transparent reservoir using a high-speed camera. Fabrication of the fibers took less than 1 s. Using centrifugal spinning, we studied the formation of the fibers at three different rotational speeds, and for pressurized gyration, one rotational speed was studied with three different nitrogen gas pressures. Using the pressurized gyration technique at a gas pressure of 0.3 MPa, there was significant improvement in the production yield of the fibers. We found a strong correlation between the variation of pressure and the rate of the solution leaving the reservoir with the improved morphology of the fibers. The use of reduced power techniques, like centrifugal spinning and pressured gyration, to yield high-quality nonwoven nanofibers and microfibers in large quantities is important due to their use in rapidly expanding markets. (C) 2019 Author(s).