Optimizing the alignment of thermoresponsive poly(N-isopropyl acrylamide) electrospun nanofibers for tissue engineering applications: A factorial design of experiments approach

Abstract

Thermoresponsive polymers, such as poly(N-isopropyl acrylamide) (PNIPAM), have been identified and used as cell culture substrates, taking advantage of the polymer’s lower critical solution temperature (LCST) to mechanically harvest cells. This technology bypasses the use of biochemical enzymes that cleave important cell-cell and cell-matrix interactions. In this study, the process of electrospinning is used to fabricate and characterize aligned PNIPAM nanofiber scaffolds that are biocompatible and thermoresponsive. Nanofiber scaffolds produced by electrospinning possess a 3D architecture that mimics native extracellular matrix, providing physical and chemical cues to drive cell function and phenotype. We present a factorial design of experiments (DOE) approach to systematically determine the effects of different electrospinning process parameters on PNIPAM nanofiber diameter and alignment. Results show that high molecular weight PNIPAM can be successfully electrospun into both random and uniaxially aligned nanofiber mats with similar fiber diameters by simply altering the speed of the rotating mandrel collector from 10,000 to 33,000 RPM. PNIPAM nanofibers were crosslinked with OpePOSS, which was verified using FTIR. The mechanical properties of the scaffolds were characterized using dynamic mechanical analysis, revealing an order of magnitude difference in storage modulus (MPa) between cured and uncured samples. In summary, cross-linked PNIPAM nanofiber scaffolds were determined to be stable in aqueous culture, biocompatible, and thermoresponsive, enabling their use in diverse cell culture applications.

Modulating electrospun polycaprolactone scaffold morphology and composition to alter endothelial cell proliferation and angiogenic gene response

“…and bioelectric cues (electrical stimulation) [2][3][4][5][6][7][8][9][10][11]. Electrospinning is an exciting avenue that allows for a wide range of scaffold morphologies to be created [12][13][14][15]. This method has been used in many aspects of tissue engineering to mimic the structure of the native ECM, allowing for improved environments for cell adhesion, migration and proliferation [16,17].…”

3D Printing of Thermoresponsive Hydrogel Laden with an Antimicrobial Agent towards Wound Healing Applications

“…Non-cytotoxicity is one of the most important criteria determining the feasibility of hydrogels as wound healing dressings. Although we used components that have been proved to be biocompatible, their combination in a composite material has not been tested for cytotoxicity [62][63][64][65]. Moreover, calcium alginate dressings have shown positive effects on wound healing by providing a moist wound environment [63].…”

Fabrication techniques of biomimetic scaffolds in three‐dimensional cell culture: A review

“…An example of synthetic‐synthetic blend is PNIPAM–PCL scaffold for manipulating thermosensitive response for cellular harvesting (Young et al, 2019). PNIPAM with its lower critical solution temperature provides (LCST of ~32°C) an added advantage for the scaffold to circumvent the use of enzymes like trypsin and enhances surface area to volume ratio for cellular proliferation.…”

“…Polymers are generally mixed in different concentration ratios after optimization of either natural with natural polymer, or natural with synthetic polymer, or synthetic with a different synthetic polymer. One of the instances of composites enclosing naturalYoung et al, 2019). PNIPAM with its lower critical solution temperature provides (LCST of~32°C) an added advantage for the scaffold to circumvent the use of enzymes like trypsin and enhances surface area to volume ratio for cellular proliferation.…”