Enhancing Bone Scaffold Fabrication: A Comparative Study of Manual Casting and Automated 3D Bioprinting

Abstract

While fabrication of bone scaffolds is important for the development of tissue engineering, traditional techniques have typically been prone to either scaling or reproducibility issues. This paper highlights a strategy for automated 3D printing and bioprinting techniques that enhance precision and efficiency in the production of PLGA-HA scaffolds. We realized significant improvements in efficiency, reproducibility, and scalability through optimization of 3D printing parameters, improvement of material handling, and refinement of the fabrication process. Precise measurement consequently minimized material waste; the introduction of a mesh filter allowed for high-throughput experimentation without compromising the integrity of individual scaffolds, streamlining the workflow. Combining automated casting with state-of-the-art 3D bioprinting, our experimental methodology precisely applied the bioactive materials, reducing the processing time fivefold and enhancing precision. Besides, automated casting produced thicker, better-quality scaffolds averaging 0.02354 g, which is against 0.01169 g using the manual approach, effectively doubling the retention of the PLGA-HA coating on a PVA mold. Excellent cell viability and adhesion on automated scaffolds have been further underlined for application in tissue engineering during in vitro studies using multipotent mesenchymal stromal cells. Although conventional techniques, such as injection molding, are standard for large lots, 3D printing has advantages in scaffold fabrication regarding control over geometry and homogeneous material properties. Equally important, these characteristics are necessary to achieve repeatable and up-scaled experimental results.

Keywords: 3D printing; Automation; Bioprinting; Bone regeneration; In vitro; Tissue engineering.

Fig. 1

Design and fabrication of the PLA mesh filter for a 24-sample well plate

Fig. 2

Manual vs. automated PLGA–HA solution casting on PVA molds. Manual casts were extruded sequentially on a vortex mixer for distribution. Automated casting occurred in batches without a mixer

Fig. 3

Comparison of scaffolds produced through manual casting (left, showing soggy, and inconsistent structures) versus automated casting (right, uniform, and reproducible scaffolds), demonstrating the structural consistency achieved with automation

Fig. 4

Time taken to cast four scaffolds using the manual method, automated with a 2.5 mL syringe, and automated with a 5 mL syringe

Fig. 5

Average scaffold weights for manual casting (left) versus automated casting (right), showing greater material retention with automation

Fig. 6

FTIR spectra of the manual and automated PLGA–HA scaffolds and functional group components

Fig. 7

SEM images showing the microstructural differences between PLGA–HA scaffolds fabricated via automated casting (a, a′, a″; b, b′, b″) and manual casting (c, c′, c″; d, d′, d″) at magnifications of × 25, × 2000, and × 10,000, respectively

Fig. 8

Mechanical compression curves for the manual and automated fabrication of the PLGA–HA scaffolds

Fig. 9

Microscopic images of cell-seeded bone scaffolds. a–c Represent images of the automated scaffolds at 0, 24, and 72 h, respectively. d–f Represent images of the manual scaffolds at 0, 24, and 72 h, respectively