This research investigates the suitability of printed polyamide 12 (PA12) and its dyed version to support cells in bioengineering applications. For this purpose, human gingival fibroblasts (hGF06) were cultured on PA-12 scaffolds that were 3D-printed by Multi Jet Fusion (MJF). The study examined the direct cultivation of cells on MJF-printed cell culture scaffolds and the effect of leachate of PA-12 printed by MJF on the cultured cells. The article presents research on the surface treatment of PA12 material used in 3D printing and the effect of automatic staining on cell vitality and proliferation in vitro. The study presents a unique device designed exclusively for staining prints made of the biocompatible material PA12 and demonstrates the compatibility of 3D-printed polyamide 12 parts stained in the novel device with a nutrient culture medium and cells. This novel PA12 surface treatment for biomedical purposes does not affect the compatibility with the culture medium, which is essential for cell viability and proliferation. Fluorescence microscopy revealed that mitochondrial fitness and cell survival were not affected by prolonged incubation with clear or dyed PA12 3D-printed parts.

This study describes the development, technical validation, and preliminary biological evaluation of a custom-built, low-cost device designed to apply low-amplitude mechanical vibrations to cultured cells. The system consists of 3D-printed PLA components and a miniature loudspeaker (8 Ω, 0.5 W) driven by a pulse-width modulation (PWM) module. The electrical excitation signal was verified using digital oscilloscopy and Fast Fourier Transform (FFT) analysis, which confirmed a stable fundamental frequency of 30 Hz within the mechanically effective operating range of the actuator (approximately 20–90 Hz); higher harmonic components at integer multiples of the fundamental frequency (60–180 Hz), characteristic of rectangular PWM excitation, were also detected. At the stimulation setting (30 Hz, 30% duty cycle), a MEMS accelerometer at the culture position recorded a resultant acceleration of 1.04–1.10 g (vibration-related component of approximately 0.04–0.10 g). Human gingival fibroblasts (GF06) cultured in 35 mm Petri dishes were exposed to daily vibration outside a CO₂ incubator, and their response was evaluated using the MTT assay and an in vitro wound healing (scratch) assay. After 24 h of daily 15 min stimulation, the metabolic activity of vibration-treated cultures exceeded that of the controls by approximately 15 and 25 percentage points at the lower and higher seeding densities, respectively; however, these differences were not statistically significant (p = 0.189 and p = 0.098). When the daily stimulation duration was varied, the MTT signal after 72 h increased with the stimulation duration, reaching approximately 115%, 134%, and 154% of the control for 150, 300, and 450 s, respectively (p < 0.05 for 300 and 450 s). In the scratch assay, stimulation for 450 s increased gap closure compared with the control after 6 h (35.4% vs. 3.4%) and 24 h (53.4% vs. 21.2%; p < 0.01). No evident cytotoxic effects were observed under the tested conditions. The study demonstrates the technical feasibility of the platform and its ability to elicit a measurable, stimulation duration-dependent biological response, and it provides a basis for future experiments that include direct mechanical characterization of the stimulus and larger numbers of independent biological replicates under controlled physiological conditions.