Page 352 - IJB-9-6

International Journal of Bioprinting Surface modification of PCL scaffolds

1. Introduction proportions of nanohydroxyapatite with PCL to improve
the biocompatibility and surface morphology of the
Craniofacial bone defects not only have a serious impact scaffold . Additionally, chitosan and hyaluronic acid
[35]
on the patient’s quality of life but also represent a challenge have been utilized to improve the biocompatibility and
[1]
for surgeon . The clinical treatments for craniofacial hydrophilicity of PCL . Furthermore, the application
[36]
bone defects mainly include autogenous grafts, allogeneic of calcium phosphate coating on the surface of PCL
[2]
grafts, and engineered bone . Despite being the standard scaffolds has been shown to enhance biological activity .
[37]
treatment for bone defects, autograft is limited by a lack Despite the potential benefits, the current problems in
of tissue source. Although allogeneic bone is widely surface modification of PCL scaffolds lie in the complex
used, it carries the risk of immune rejection and disease procedures and relatively high cost. Therefore, there is a
transmission [3,4] . In this context, engineered bone shows need to develop a more convenient and efficient method
great potential for the treatment of bone defects [5-7] .
for this process.
Melt electrospinning writing (MEW) is an innovative
Alkaline hydrolysis has been reported as a simple
three-dimensional (3D) printing technique that enables and effective method for surface modification . Sodium
[38]
the creation of structures with precisely arranged hydroxide (NaOH) treatment is capable of not only
microfibers, making it a promising technology for bone adding functional groups to polymer surfaces, but also
tissue engineering applications [8-10] . Both pore size and inducing surface porosity through etching. This capability
fiber diameter can be easily controlled by adjusting the is not commonly found in other surface modification
printing parameters to meet the specific requirements of techniques . Thus, the dual action of NaOH makes
[38]
various tissues . Several studies have demonstrated the it a suitable option for modifying the surface of PCL.
[11]
benefits of utilizing MEW scaffolds in tissue engineering, It is worth noting that previous studies have primarily
such as wound healing, regeneration of periodontal tissue, focused on examining the impact of alkaline treatment
and restoration of the acetabular labrum [12-14] . To date, on the physicochemical properties and cytocompatibility
limited research has been conducted on the utilization of PCL [39-41] . However, there is limited research on the
of MEW scaffolds for bone defect repair [15-17] . Therefore, effects of alkaline treatment on the differentiation of
additional investigations are needed to determine the bone marrow mesenchymal stem cells (BMSCs). Based
effectiveness and potential applications of MEW scaffolds on the interactions between BMSCs and scaffolds, it
in craniofacial bone regeneration.
is hypothesized that surface modification mediated by
Recently, some synthetic polymers have been used NaOH treatment could induce osteogenic differentiation
to prepare MEW scaffolds, including polycaprolactone of BMSCs.
(PCL), poly (L-lactic acid) (PLLA), and polyethylene oxide
(PEO) [18-20] . Of these, PCL is a highly desirable material To verify this hypothesis, the effects of NaOH
due to its exceptional printability and low melting point . treatment on physicochemical properties of PCL scaffolds
[21]
It has been extensively utilized in numerous biological were investigated, including surface morphology,
applications such as bone grafts, drug delivery systems, and surface roughness, and hydrophilicity. Moreover, in vitro
skin grafts [22-24] . However, several studies have highlighted experiments were performed to assess the impact of
the weakness of PCL scaffold, particularly in bone NaOH treatment-mediated surface modification on
integration after implantation, owing to its low cellular osteogenic differentiation and the mechanisms behind it.
affinity [25,26] . Consequently, researchers have focused on Finally, in vivo experimentations were conducted to assess
improving the cytocompatibility of PCL. bone regeneration of surface-modified PCL scaffolds
(Scheme 1).
Previous studies have shown that modifying the
surface of a scaffold can improve its cellular affinity 2. Materials and methods
and cytocompatibility. This can be achieved through
modifications in hydrophilicity, roughness, and 2.1. Scaffold preparation
morphology [27,28] . For example, the favorable hydrophilicity The PCL scaffold was prepared using a commercial MEW
can facilitate cell adhesion and proliferation [29,30] . In printing platform (BioPioneer-1, Shaanxi Bioprintissue
addition, the specific micro/nanostructures on a surface Medical Technologies Co., Ltd.). In brief, PCL pellets were
and their appropriate roughness can have an impact loaded into a metal cartridge and melted at 90°C to obtain
on the attachment, morphology, spreading, and even a homogeneous fluid. The scaffolds were then printed
differentiation of cells [31,32] . Currently, various methods using a 26G nozzle at a voltage of -7 kV and a printing
have been attempted to enhance the surface properties speed of 40 mm/s. The air pressure was set at 10 MPa, and
of PCL [26,33,34] . One such method involves mixing varying the distance between the collector and nozzle was 4 mm.

Volume 9 Issue 6 (2023) 344 https://doi.org/10.36922/ijb.1071