Core–shell PVA/gelatin nanofibrous scaffolds using co-solvent, aqueous electrospinning: Toward a green approach

© 2018 Wiley Periodicals, Inc. Electrospinning (ES) of gelatin often requires cytotoxic organic solvents or acidic environments, which deteriorate cell recognition sites. In this study, aqueous, non-toxic, co-solvent ES was performed to obtain core–shell poly(vinyl alcohol) (PVA)/gelatin nanofiber scaffolds. Effects of the core/shell feed rate ratio (FRR) were investigated on a morphological and mechanical basis. PVA:gelatin ratio of 1:4 was the limiting ratio for specific voltage and electrode distance parameters to obtain uniform fibers. Core–shell bead-free structures were obtained at 8% PVA and gelatin aqueous solutions. A mean diameter of 280 nm was obtained for 1:1 FRR at 15 kV and 15 cm of electrode distance. Crosslinking resulted in slight improvement in tensile strengths and severe decrease in ductility. Fourier transform infrared spectra revealed retention and improvement of stable secondary structures of gelatin after ES. The scaffolds almost degraded more than 60% in 14 days. Based on the results, present scaffolds hold great promise as suitable candidates for biomedical applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46582

Effect of citric acid on thermal, phase morphological, and mechanical properties of poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide)/thermoplastic starch blends

This work investigated the thermal, morphological, and tensile properties of poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide) (PLLA-PEG-PLLA)/thermoplastic starch (TPS) blends with 3 wt% citric acid (CA) treatment of TPS. The blends with PLLA-PEG-PLLA/CA-TPS ratios of 100/0, 90/10, 80/20, and 60/40 (w/w) were investigated and compared with PLLA-PEG-PLLA/CA-free TPS blends. Crystallizability of the blends decreased and thermal stability increased as the TPS content increased. The thermal stability of the blends was found to improve after CA treatment of TPS. The PLLA-PEG-PLLA/CA-TPS blends showed better phase compatibility than those of the PLLA-PEG-PLLA/CA-free TPS blends. The tensile properties of the blends were improved by CA treatment of TPS. In conclusion, improvement in thermal stability, phase compatibility, and tensile properties of the PLLA-PEG-PLLA/TPS blends was obtained by CA treatment of TPS. The resulting PLLA-PEG-PLLA/CA-TPS blends could potentially be used to prepare biodegradable and flexible bioplastics

Enhancement in Crystallizability of Poly(L-Lactide) Using Stereocomplex-Polylactide Powder as a Nucleating Agent

High-molecular-weight poly(L-lactide) (HMW-PLLA) is a promising candidate for use as a bioplastic because of its biodegradability and compostability. However, the applications of HMW-PLLA have been limited due to its poor crystallizability. In this work, stereocomplex polylactide (scPLA) powder was prepared by precipitation of a low-molecular-weight poly(L-lactide)/poly(D-lactide) (LMW-PLLA/LMW-PDLA) blend solution and investigated for use as a fully-biodegradable nucleating agent for HMW-PLLA compared to LMW-PLLA powder. The obtained LMW-PLLA and scPLA powders with a nearly spherical shape showed complete homo- and stereocomplex crystallites, respectively. HMW-PLLA/LMW-PLLA powder and HMW-PLLA/scPLA powder blends were prepared by melt blending. The LMW-PLLA powder was homogeneously melted in the HMW-PLLA matrices, whereas the scPLA powder had good phase compatibility and was well-dispersed in the HMW-PLLA matrices, as detected by scanning electron microscopy (SEM). It was shown that the enthalpies of crystallization (ΔHc) upon cooling scans for HMW-PLLA largely increased and the half crystallization time (t1/2) dramatically decreased as the scPLA powder content increased; however, the LMW-PLLA powder did not exhibit the same behavior, as determined by differential scanning calorimetry (DSC). The crystallinity content of the HMW-PLLA/scPLA powder blends significantly increased as the scPLA powder content increased, as determined by DSC and X-ray diffractometry (XRD). In conclusion, the fully biodegradable scPLA powder showed good potential for use as an effective nucleating agent to improve the crystallization properties of the HMW-PLLA bioplastic

Comparative Study of Tailor-made Mesh Plug Herniorrhaphy Versus Lichtenstein Herniorrhaphy Versus Bassini Operation: A Prospective Clinical Trial

Operations to cure inguinal hernia are among the most common surgical procedures. However, the most effective surgical technique for inguinal hernia repair is unknown, and the recurrence at 5 years varies between 1% and 10%. Surgical techniques and implanted materials are crucial to the result of and costs associated with hernia repair. The objective of this study was to determine whether the tailor-made mesh plug for inguinal hernia repair was as effective and safe as other methods of herniorrhaphy. Methods: Of 94 patients who had a primary diagnosis of inguinal hernia prospectively included in the study, 25 were treated with tailor-made mesh plug herniorrhaphy, 26 with Lichtenstein herniorrhaphy and 36 with the Bassini operation. The primary outcome was the recurrence of hernia at 1 year, and secondary outcomes included surgical complications and hospital stay. Results: There was no postoperative mortality in this study. Three patients had recurrence after Bassini operation, but there was no recurrent hernia after Lichtenstein or mesh plug herniorrhaphy. Groin swelling and ecchymosis were found in two patients (1 tailor-made mesh plug, 1 Lichtenstein herniorrhaphy). No surgical site infection occurred. Mean operating time was 60 minutes (range, 45-75 minutes) for tailor-made mesh plug herniorrhaphy, 82 minutes (range, 30-120 minutes) for Lichtenstein herniorrhaphy, and 82 minutes (range, 30-135 minutes) for the Bassini operation. Conclusion: Tailor-made mesh plug herniorrhaphy is a safe operation. The mesh plug material (Mersilene) was cheap. The recurrence rate was lower with tailor-made mesh plug herniorrhaphy than with the Bassini operation, but equal to that with Lichtenstein herniorrhaphy. Postoperative complications did not differ among all operations