In this study, we designed and fabricated a multilayered fibrous scaffold capable of the controlled release of multiple growth factors for sciatic nerve regeneration in rats. The scaffold consists of three layers prepared by sequential electrospinning, where the first layer is fabricated using polycaprolactone (PCL)-aligned electrospun nanofibers for the attachment and differentiation of cells toward the direction of the sciatic nerve. The second and third layers are fabricated using poly(lactic-co-glycolic acid) 6535 (PLGA 6535) and 8515 (PLGA 8515), respectively. The resultant three nanofiber layers were stacked and fixed by incorporating hydrogel micropatterns at both ends of nanofiber scaffold, which also facilitated the surgical handling of the multilayered scaffolds. The PLGA layers acted as reservoirs to release growth factors neurotrophin (NT-3), brain-derived neurotrophic factor (BDNF), and platelet-derived growth factor (PDGF). The different biodegradation rate of each PLGA layer enabled the controlled release of multiple growth factors such as NT-3, BDNF, and PDGF with different patterns. In a rat model, the injured nerve was rolled up with the multilayered scaffold loading growth factors, and behavior tests were performed five weeks after surgery. Sciatic functional index (SFI) and mechanical allodynia analysis revealed that the fast release of NT-3 and BDNF from PLGA 6535 and subsequent slow release of PDGF from PLGA 8515 proved to be the greatest aid to neural tissue regeneration. In addition to the biochemical cues from growth factors, the aligned PCL layer that directly contacts the injured nerve could provide topographical stimulation, offering practical assistance to new tissue and cells for directional growth parallel to the sciatic nerve. This study demonstrated that our multilayered scaffold performs a function that can be used to promote locomotor activity and enhance nerve regeneration in combination with align-patterned topography and the controlled release of growth factors.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korea government (MSIP) (Grants 2015R1D1A1A01060444, 2017M3D1A1039289, 2009-0093823, 2014M3A7B4051596, 2016R1A6A3A11932752, and 2017R1A2B3011586) and the Technology Innovation Program funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea) (Grant 10062712, Development of spinal fusion implant and its manufacturing system; the functionality optimized, patient-customized in terms of bioactive materials to meet the clinical needs).
© 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Biomedical Engineering