In Situ Generation of Cellulose Nanocrystals in Polycaprolactone Nanofibers: Effects on Crystallinity, Mechanical Strength, Biocompatibility, and Biomimetic Mineralization

Abstract

Post-electrospinning treatment is a facile process to improve the properties of electrospun nanofibers for various applications. This technique is commonly used when direct electrospinning is not a suitable option to fabricate a nonwoven membrane of the desired polymer in a preferred morphology. In this study, a representative natural-synthetic hybrid of cellulose acetate (CA) and polycaprolactone (PCL) in different ratios was fabricated using an electrospinning process, and CA in the hybrid fiber was transformed into cellulose (CL) by post-electrospinning treatment via alkaline saponification. Scanning electron microscopy was employed to study the effects of polymer composition and subsequent saponification on the morphology of the nanofibers. Increasing the PCL content in the PCL/CA blend solution caused a gradual decrease in viscosity, resulting in smoother and more uniform fibers. The saponification of fibers lead to pronounced changes in the physicochemical properties. The crystallinity of the PCL in the composite fiber was varied according to the composition of the component polymers. The water contact angle was considerably decreased (from 124° to less than 20°), and the mechanical properties were greatly enhanced (Young's Modulus was improved by ≈20-30 fold, tensile strength by 3-4 fold, and tensile stress by ≈2-4 fold) compared to those of PCL and PCL/CA membranes. Regeneration of cellulose chains in the nanofibers increased the number of hydroxyl groups, which increased the hydrogen bonding, thereby improving the mechanical properties and wettability of the composite nanofibers. The improved wettability and presence of surface functional groups enhanced the ability to nucleate bioactive calcium phosphate crystals throughout the matrix when exposed to a simulated body fluid solution. Experimental results of cell viability assay, confocal microscopy, and scanning electron microscopy imaging showed that the fabricated nanofibrous membranes have excellent ability for MC3T3-E1 cell proliferation and growth. Given the versatility and widespread use of cellulose-synthetic hybrid systems in the construction of tissue-engineered scaffolds, this work provides a novel strategy to fabricate the biopolymer-based materials for applications in tissue engineering and regenerative medicine.

Cocoa Shell Waste Biofilaments for 3D Printing Applications

“…Moreover, the crystallinity of PCL in the extruded biofilaments was preserved . Similar changes on the elastic modulus of pure PCL filled with cellulose nanocrystals/cellulose nanowhiskers have also been reported in the literature . The biofilaments PCL.CSW 90.10, containing 10% by wt.…”

“…More importantly, changes in crystallinity due to compounding greatly influence the properties and performance of thermoplastics and resultant filaments for 3D printing . For this reason, the effect of micronized CSW on the crystallinity of PCL was also monitored by FTIR measurements ( Figure a,b) under different temperatures ranging from room temperature to temperatures above the polymer melting point.…”

“…At temperatures below 100 °C, no significant weight loss in pure PCL filament was observed. Thermal degradation of pure PCL filament occurred as a single step at 400 °C ( T 1 ), which is attributed to random polymer chain cleavage via ester pyrolysis reactions . Due to thermal elimination of adsorbed moisture, TGA curve of micronized CSW showed an initial 7% weight loss at 100 °C .…”

Cellulose monoacetate/polycaprolactone and cellulose monoacetate/polycaprolactam blended nanofibers for protease immobilization

“…Figure shows ATR‐FTIR spectra of the produced PCL/CMA and PA6/CMA blended nanofibers with different CMA ratios. In pure PCL nanofibers [Figure (A,a)], an intense peak detected at 1726 cm −1 comes from the presence of a CO stretching band of ester groups, and the typical absorption bands of CH 2 observed at 2943 and 2864 cm −1 correspond to stretching of CH 2 groups . The band at 1467 cm −1 corresponds to asymmetric deformation of CH 3 , and the peak at 1165 cm −1 comes from the symmetric stretching of COC in PCL NFs .…”

Determination of Bovine Serum Albumin Adsorption Capacity of Newly Obtained Cellulose extracted from Glycyrrhiza glabra (Licorice)

“…3 Many recent studies have focused on testing the biocompatibility of cellulose. [4][5][6][7][8][9] However, few studies have been reported on the interaction of plant cellulose with serum albumin proteins, which are the major components of blood serum. [10][11][12] This study was designed to exploit Glycyrrhiza glabra as a new source for cellulose isolation and to test its interaction with bovine serum albumin (BSA).…”