Preliminary Evaluation of 3D Printed Chitosan/Pectin Constructs for Biomedical Applications

Abstract

In the present study, chitosan (CS) and pectin (PEC) were utilized for the preparation of 3D printable inks through pneumatic extrusion for biomedical applications. CS is a polysaccharide with beneficial properties; however, its printing behavior is not satisfying, rendering the addition of a thickening agent necessary, i.e., PEC. The influence of PEC in the prepared inks was assessed through rheological measurements, altering the viscosity of the inks to be suitable for 3D printing. 3D printing conditions were optimized and the effect of different drying procedures, along with the presence or absence of a gelating agent on the CS-PEC printed scaffolds were assessed. The mean pore size along with the average filament diameter were measured through SEM micrographs. Interactions among the characteristic groups of the two polymers were evident through FTIR spectra. Swelling and hydrolysis measurements confirmed the influence of gelation and drying procedure on the subsequent behavior of the scaffolds. Ascribed to the beneficial pore size and swelling behavior, fibroblasts were able to survive upon exposure to the ungelated scaffolds.

Keywords: 3D printing; chitosan; hydrogels; pectin.

Figure 1

Viscosity dependency of the samples CS-PEC 4–5%, CS-PEC 4–10%, CS-PEC 5–5% and CS-PEC 5–10% at different shear rates.

Figure 2

(a) Viscosity and (b) storage modulus (G′, infilled symbols) and loss modulus (G″, hollow symbols) dependency over temperature at fixed frequencies of the sample CS-PEC 5–10%.

Figure 3

Photos of 3D printed (a) CS solution 4% w/v and of the samples (b) CS-PEC 4–5%, (c) CS-PEC 4–10%, (d) CS-PEC 5–5% and (e) CS-PEC 5–10%.

Figure 4

Photos of dried samples and SEM micrographs of the printed scaffolds (a) CS-PEC RD, (b) CS-PEC FD, (c) CS-PEC G RD and (d) CS-PEC G FD.

Figure 4

Photos of dried samples and SEM micrographs of the printed scaffolds (a) CS-PEC RD, (b) CS-PEC FD, (c) CS-PEC G RD and (d) CS-PEC G FD.

Figure 5

Average (a) filament diameter and (b) pore size of the samples CS-PEC RD, CS-PEC FD, CS-PEC G RD and CS-PEC G FD. 5 measurement were performed for each sample.

Figure 6

FTIR spectra of the 3D printed samples CS-PEC RD, CS-PEC FD CS-PEC G RD and CS-PEC G FD.

Figure 7

Possible interactions between the end groups of CS and PEC.

Figure 8

(a) Degree of swelling, (b) water content and (c) dehydration of the samples CS-PEC RD, CS-PEC FD, CS-PEC G RD and CS-PEC G FD as a function of time.

Figure 9

Mass loss during enzymatic hydrolysis of the samples CS-PEC RD, CS-PEC FD, CS-PEC G RD and CS-PEC-G FD.

Figure 10

DSC curves of CS-PEC RD, CS-PEC FD, CS-PEC G RD and CS-PEC G FD.

Figure 11

(a) MTT assays results on the proliferation of fibroblasts exposed to the scaffolds. Mean ± SD. * p ≤ 0.05, (b) Hematoxylin-and-eosin-stained image of fibroblasts seeded on the CS/Pec RD construct.

Figure 12

(a) 3D model of the constructs with dimensions 2 × 2 × 0.1 mm and after slicing with Slic3r (6 layers) and (b) process flow of file preparation for 3D printing.