A preliminary cytocompatibility study of electrospun nanofibrous matrices for their integration into a fiber-based biophotonic sensing platform

Introduction: The use of diagnostic methods or devices that are increasingly efficient, accurate, and able to ensure prompt intervention to prevent the progression of aggressive pathologies, such as cancer, is now more fundamental than ever. In this context, to assess the sensing capacity in the presence of tumor cells with a biophotonic platform, based on lossy mode resonance fiber sensors coated with scaffolded nanomaterials and integrated with microfluidic chips, we have preliminarily electrospun three different nanofibrous substrates onto glass planar supports and evaluated their cytocompatibility with a cellular model of human osteosarcoma.

Methods: About 18.000 cells were seeded in complete growth medium onto uncoated or treated glass coverslips in 12-well plates. Cell adhesion, morphology and proliferation were observed after 24 and 48 hours by optical microscopy and several images were captured by using a 10× objective lens magnification after cell washing and medium renewal. A colorimetric cell viability assay was then performed at 48 hours by transferring each coverslip into new multi-well plates and by adding 5% Water-Soluble Tetrazolium 8 (WST-8) in complete medium for 2 hours at 37°C. Cell supernatants were transferred into 96-well plates to quantify the absorbance of formazan at 450 nm using a microplate reader. Formazan is produced via WST-8 reduction by mitochondrial dehydrogenases of viable cells and results in a yield directly proportional to the number of living cells.

Results: Except for a single polymer, all matrices remained unchanged after the incubation with cell culture medium for up to 48 hours. In all electrospun coverslips, cells had properly adhered to the substrates, and their morphology was comparable to the control cells seeded onto uncoated supports. The cells were metabolically active and the viable amount in all treated samples was comparable to relative controls.

Conclusions: These promising results lay the groundwork for the next phase of optimization of the final biophotonic sensing device integrated with microfluidics.