Engineering multifunctional bactericidal nanofibers for abdominal hernia repair.

The engineering of multifunctional surgical bactericidal nanofibers with inherent suitable mechanical and biological properties, through facile and cheap fabrication technology, is a great challenge. Moreover, hernia, which is when organ is pushed through an opening in the muscle or adjacent tissue due to damage of tissue structure or function, is a dire clinical challenge that currently needs surgery for recovery. Nevertheless, post-surgical hernia complications, like infection, fibrosis, tissue adhesions, scaffold rejection, inflammation, and recurrence still remain important clinical problems. Herein, through an integrated electrospinning, plasma treatment and direct surface modification strategy, multifunctional bactericidal nanofibers were engineered showing optimal properties for hernia repair. The nanofibers displayed good bactericidal activity, low inflammatory response, good biodegradation, as well as optimal collagen-, stress fiber- and blood vessel formation and associated tissue ingrowth in vivo. The disclosed engineering strategy serves as a prominent platform for the design of other multifunctional materials for various biomedical challenges.

In Vitro and in Vivo Studies of Novel Poly(D,L-lactic acid), Superhydrophilic Carbon Nanotubes, and Nanohydroxyapatite Scaffolds for Bone Regeneration.

Poly(D,L-lactide acid, PDLLA) has been researched for scaffolds in bone regeneration. However, its hydrophobocity and smooth surface impedes its interaction with biological fluid and cell adhesion. To alter the surface characteristics, different surface modification techniques have been developed to facilitate biological application. The present study compared two different routes to produce PDLLA/superhydrophilic vertically aligned carbon nanotubes:nanohydroxyapatite (PDLLA/VACNT-O:nHAp) scaffolds. For this, we used electrodeposition and immersion in simulated body fluid (SBF). Characterization by goniometry, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy confirmed the polymer modifications, the in vitro bioactivity, and biomineralization. Differential scanning calorimetry and thermal gravimetric analyses showed that the inclusion of VACNT-O:nHA probably acts as a nucleating agent increasing the crystallization rate in the neat PDLLA without structural alteration. Our results showed the formation of a dense nHAp layer on all scaffolds after 14 days of immersion in SBF solution; the most intense carbonated nHAp peaks observed in the PDLLA/VACNT-O:nHAp samples suggest higher calcium precipitation compared to the PDLLA control. Both cell viability and alkaline phosphatase assays showed favorable results, because no cytotoxic effects were present and all produced scaffolds were able to induce detectable mineralization. Bone defects were used to evaluate the bone regeneration; the confocal Raman and histological results confirmed high potential for bone applications. In vivo study showed that the PDLLA/VACNT-O:nHAp scaffolds mimicked the immature bone and induced bone remodeling. These findings indicate surface improvement and the applicability of this new nanobiomaterial for bone regenerative medicine.

In vitro and in vivo studies of a novel nanohydroxyapatite/superhydrophilic vertically aligned carbon nanotube nanocomposites.

An association between in vitro and in vivo studies has been demonstrated for the first time, using a novel nanohydroxyapatite/superhydrophilic vertically aligned multiwalled carbon nanotube (nHAp/VAMWCNT-O2) nanocomposites. Human osteoblast cell culture and bone defects were used to evaluate the in vitro extracellular matrix (ECM) calcification process and bone regeneration, respectively. The in vitro ECM calcification process of nHAp/VAMWCNT-O2 nanocomposites were investigated using alkaline phosphatase assay. The in vivo biomineralization studies were carried out on bone defects of C57BL/6/JUnib mice. Scanning electron microscopy, micro-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and X-ray difractometry analyses confirmed the presence of the nHAp crystals. nHAp/VAMWCNT-O2 nanocomposites induced in vitro calcification of the ECM of human osteoblast cells in culture after only 24 h. Bone regeneration with lamellar bone formation after 9 weeks was found in the in vivo studies. Our findings make these new nanocomposites very attractive for application in bone tissue regeneration.