Novel opportunities and challenges offered by nanobiomaterials in tissue engineering

Abstract

Over the last decades, tissue engineering has demonstrated an unquestionable potential to regenerate damaged tissues and organs. Some tissue-engineered solutions recently entered the clinics (eg, artifi cial bladder, corneal epithelium, engineered skin), but most of the pathologies of interest are still far from being solved. The advent of stem cells opened the door to large-scale production of "raw living matter" for cell replacement and boosted the overall sector in the last decade. Still reliable synthetic scaffolds fairly resembling the nanostructure of extracellular matrices, showing mechanical properties comparable to those of the tissues to be regenerated and capable of being modularly functionalized with biological active motifs, became feasible only in the last years thanks to newly introduced nanotechnology techniques of material design, synthesis, and characterization. Nanostructured synthetic matrices look to be the next generation scaffolds, opening new powerful pathways for tissue regeneration and introducing new challenges at the same time. We here present a detailed overview of the advantages, applications, and limitations of nanostructured matrices with a focus on both electrospun and self-assembling scaffolds.

Electrospun 3D multi-scale fibrous scaffold for enhanced human dermal fibroblasts infiltration

“…HDFs seeded on gelatin grafted 2D electrospun scaffold were found to adhere on the top surface only, despite the enhanced wettability ( Figure 6B). This is a common issue that has restricted the application of electrospun scaffold [9,10] . By increasing the pore size of the scaffold using needle collector, better cellular distribution at seeding was observed even for the unmodified 3D multi-scale scaffold.…”

“…This results in densely packed nanofibers with reduced pore size and porosity and it is challenging to build a scaffold with thickness beyond 100 µm using this conventional method [9] . The limited cell infiltration due to the densely packed structure and small pore size has restricted the application of electrospun scaffold [10] . Numerous approaches have been reported to increase the pore size of the traditional electrospun scaffold [11,12] , including mechanical expansion [13] , inclusion of porogen [14] , increment of the fiber diameter [15] , incorporation of sacrificial fibers [16,17] , cryogenic electropinning [18] , and addition of microscale (3~10 µm) [19,20] or macroscale (~300 µm) [21,22] fibers into the nanoscale fiber (~600 nm) scaffold.…”

Tissue Engineering for Tissue and Organ Regeneration

“…(Greiner, 2008;Zhong, 2010) In addition to being used to fabricate nonwoven mats for wound dressings, there is currently much interest in making scaffolds for bladder tissue engineering. Gelain, 2008) Baker et al used a 3D electrospun nanoscaffold of polystyrene to determine whether the phenotype of cells isolated from the stroma of human ureter specimens could be modulated by growing cells within such scaffold. (Baker, 2008) Non-aligned scaffolds made out of fibers with mean diameter of 200 nm were used in that study.…”

Advances of Nanotechnology in the Stem Cells Research and Development

“…The regulation of stem cells depends largely on their interaction with a highly specialized microenvironment or "niches" [98]. Secreted factors, stem cell neighboring cell interactions, extracellular matrix (ECM) and mechanical properties collectively make up the stem cell microenvironment.…”