Processing‐structure‐property relationships of biopolyester/zinc oxide fibrous scaffolds engineered by centrifugal spinning

Abstract

This study addresses the processing of nonwoven fibrous materials obtained by centrifugal spinning method, namely Forcespinning; a high yield and low production cost technique little explored in this field. Poly(D, L‐lactic acid) (PDLLA) and poly(3‐hydroxybutyrate) (PHB) were used as matrices and reinforced with zinc oxide nanoparticles (n‐ZnO). The morphology, mechanical, and thermal performance of the developed composites were analyzed as well as the antibacterial effect of n‐ZnO. Fibrous materials with n‐ZnO concentrations of 1, 3, and 5 wt. % for PDLLA and 1 and 3 wt. % for PHB were evaluated. The results showed that the incorporation of n‐ZnO produces an increase in the viscosity of the precursor solutions for both polymeric systems, which caused an increase in the average fiber diameter, though the morphology was not affected, obtaining mostly long, continuous, and homogenous fibers. In addition, a decrease in thermal stability was observed to a greater extent in PDLLA systems. Regarding the mechanical performance, optimal properties were obtained at a concentration of 3 and 1 wt. % of n‐ZnO for PDLLA and PHB, respectively. Antibacterial studies showed that PHB with 1 and 3 wt. % of n‐ZnO effectively combat strains of E. coli and S. aureus, presenting 100% of strain growth inhibition. In the case of PDLLA, a higher n‐ZnO concentration (5 wt. %) was required to reach a strain growth inhibition above 97%. Finally, cell viability tests demonstrated that the designed fibrous mats support cell proliferation, indicating their potential for use as scaffolds in bone tissue regeneration.

Centrifugally spun mats based on biopolyesters/hydroxyapatite and their potential as bone scaffolds

“…In the case of PHB systems (Figure 7(b)) during the first heating cycle similar transitions are observed in systems with and without n‐Hap, with negligible modifications to the melting temperatures. PHB is composed of 95% poly(3‐hydroxybutyrate) (3‐PHB), 4% poly(4‐hydroxybutyrate) (4‐PHB) and 1% polyhydroxyvalerate (3‐PHV), therefore, in the first heating two endothermic peaks at 48 and 170°C are identified, corresponding to the melting of the 4‐PHB and 3‐PHB crystalline phases, respectively 32 . Regarding the percentage of polymer crystallinity ( X c ), the n‐Hap caused a slight increase in X c at a concentration of 5 wt.% and from 10 wt.% (with a greater impact to 15 wt.%) a decrease was observed, being 47.4, 49.2, 43.0, and 40.0% for 0, 5, 10, and 15 wt.% of n‐Hap, respectively.…”

“…In the case of PHB systems (Figure 7 respectively. 32 Regarding the percentage of polymer crystallinity (X c ), the n-Hap caused a slight increase in X c at a concentration of 5 wt.% and from 10 wt.% (with a greater impact to 15 wt.%) a decrease was observed, being 47.4, 49.2, 43.0, and 40.0% for 0, 5, 10, and 15 wt.% of n-Hap, respectively. In the cooling stage, a reduction in temperature and enthalpy of crystallization was evidenced by increasing the n-Hap concentration, similar to that described by Sánchez-Arévalo et al 9 This behavior indicates that NPs are slowing the polymer crystallization process, possibly due to their interference during the packing of polymer chains.…”

“…30 The scaffold's porosity is above 90%, similar to fibers developed in our previously reported work. 31,32 Figure S5, shows the estimated scaffold pore sizes (spaces between fibers), specifically the 50% of the population which has an area above 30.52 μm 2 with most of the distribution in the 5 to 200 μm 2 range. These results pose promising potential for applications in tissue engineering.…”

Recent applications of electrical, centrifugal, and pressurised emerging technologies for fibrous structure engineering in drug delivery, regenerative medicine and theranostics

“…By combining polymer chemistry and fluid mechanics, centrifugal spinning offers a method of engineering fibrous structures in a simple, cost effective process. The main advantage here is mass production and fiber alignment [278], promoting the use of the resulting fibers in an array of applications including drug delivery [278][279][280][281][282][283][284][285], tissue engineering [286][287][288][289][290][291][292] and energy [293][294][295]. The process boasts high production rates and abilities to process a large range of materials including polymers [278,[296][297][298][299][300][301][302] ceramics [303][304][305][306][307] and carbon [308][309][310][311].…”

Fabrication of Forcespinning® nanofibers incorporating nopal extract

“…After incubation, 300 μL of sample were added to a 96-well plate and the absorbance at 570 nm measured in a microplate reader (BioRad). The protocol was modified from a previous study (Padilla-Gainza et al 26 ) for the resazurin cell viability test. 27…”