Programmed dual-electrospun fibers with a 3D substrate-independent customized biomolecule gradient

Chemotaxis has been found essential in many key biological processes, such as embryogenesis and tissue formation, cancer, wound healing, immunological disorders and inflammation etc. Spatial organization of biomolecules is, therefore, crucial in tissue engineering and disease modeling. Herein, we, for the first time, present a programmed dual-electrospun 3D scaffolds with customizable biomolecule gradients based on substrateindependent benzophenone (BP) photochemistry. Different customized fluorescent gradients/patterns were successfully obtained in polycaprolactone (PCL) fibers. In addition, a gradient of doxorubicin, a model anticancer drug, loaded by direct mixing was able to influence SW480 colorectal cancer cell viability locally. Further using a coagulation bath collector containing ethanol with low-surface tension, wet electrospun loosely packed PCL fibers were fabricated with a tailored gradient of PCL functionalized with BPITC (Benzophenone-4-isothicyanate), a heterobifunctional crosslinker, capable of inserting primary amine-binding sites into the PCL molecule/C-H bond by the substrate-independent photoreaction of BP. The so-called PCL-BPITC scaffolds could be conjugated with any target molecules (TM) with primary amines, such as proteins, and transform the PCL-BPITC gradient into a PCL-TM gradient. When a Horseradish Peroxidase (HRP)- antibody was used as a TM, a colorimetric assay similar to ELISA principle led to successful generation of the colorful product in the same gradient. Based on the substrate-independent BP photochemistry and possibility of other bifunctional crosslinkers, such as BP-maleimide, our findings suggest a great potential for the generation of 3D scaffolds of any electrospun fibers with mono/dual/multi customizable biochemical gradient(s), that may serve a new tool for broad chemotaxis-based biomedical applications such as tissue engineering and disease modeling.

Automated summary

This study presents a novel method for preparing 3D scaffolds with customizable biomolecule gradients based on photochemistry, which can achieve different gradients in fibers and influence the activity of cancer cells. This technology has the potential to provide a new tool for tissue engineering and disease modeling.