title: 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.
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Mahesh Kumar
authors: MK
authors: Joshi
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Arjun Prasad
authors: AP
authors: Tiwari
authors: Hem Raj
authors: HR
authors: Pant
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Bishnu Kumar
authors: BK
authors: Shrestha
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.|Department of Convergence Technology Engineering, College of engineering, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Han Joo
authors: HJ
authors: Kim
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Chan Hee
authors: CH
authors: Park
authors: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University , Jeonju 561-756, Republic of Korea.|Division of Mechanical Design Engineering, Chonbuk National University , Jeonju 561-756, Republic of Korea.|Eco-friendly machine parts design research center, Chonbuk National University , Jeonju 561-756, Republic of Korea.
authors: Cheol Sang
authors: CS
authors: Kim
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D055119:Elastic Modulus; D051379:Mice; D057139:Nanofibers / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C016240:polycaprolactone; C005062:acetylcellulose; D002482:Cellulose; D017886:Durapatite
keywords: alkaline saponification; biomimetic mineralization; cellulose nanocrystals; composite fiber; electrospinning; post-electrospinning treatment