Page 199 - IJB-9-6

International Journal of Bioprinting Attractiveness of 4D printing in medical field

Experts with an extensive background in 3D and 4D
printing were contacted during the CTI cycle to request
an assessment of the results, especially in the steps of
information collection strategy, data collection, and
information analysis. Their advice was used to eliminate
unsuitable data and unrelated information. Furthermore,
experts validated the reliability of the data obtained.

4. Results and discussion

4.1. Publication trends
As mentioned before, 358 publications on 4D printing
in the medical field were gathered from Scopus between
January 1, 2017, and May 9, 2023. An analysis of the
178 relevant publications was performed to obtain the
publication trends in design factors and applications of 4D
printing in the medical field. In Figure 2, it was found that Figure 2. Published documents in 4D printing from 2017 to May 2023.
the number of published documents increased over the
years, implying that this field of study has gained attention be used in electroactive scaffolds and artificial organs for
of researchers especially in the last 3 years (2020–2022). surgical training . Lin et al. (2022) prepared a 4D-printed
[36]
4.2. Global trends in 4D printing in the medical field shape memory polybutylene succinate/polylactic acid (PBS/
4.2.1. Design factors PLA) composite filament, which showed great photothermal
In the analysis, four global trends in the materials category properties and dynamic, remote, and accurately controlled
were identified. The first trend is the addition of materials 4D transformation using near-infrared (NIR) irradiation as
such as magnetic nanoparticles, poly(acrylic acid), and a stimulus. It can be utilized for porous scaffolds and tissue
carboxymethyl chitosan among others to improve hydrogel engineering. The third trend found was the fabrication
mechanical properties. Abdullah and Okay (2023) proposed of tunable metamaterials capable of undergoing large
[37]
4D-printed hydrogels based on poly(acrylic acid) with deformations . Bodaghi and Lio (2019) developed a tunable
shape memory and self-healing properties that can actuate metamaterial with reversible thermo-mechanical memory
around body temperature. Printed hydrogel exhibited operations that exhibited elastic-plastic and hyper-elastic
a high elastic modulus (215 MPa) and high toughness behaviors at different temperatures with a wide deformation
[38]
showing great potential for biomedical applications . range . It can be cold- and hot-programmed to facilitate
[33]
[38]
Song et al. (2023) presented a biodegradable hydrogel ink its application in self-deployable biomedical stents . In
prepared with biopolyurethane, carboxymethyl chitosan 2020, Xin et al. (2020) developed a chiral metamaterial
(CMCS), and carbomer (CBM) . The ink exhibited high with tunable, programmable, and reconfigurable properties
[34]
tensile strength (maximum stress of 0.66 MPa, elongation that had bending and stretching behaviors, making it great
[39]
at break of 643%), great water retention (85.87%), ionic for tissue engineering applications . Wan et al. (2022)
conductivity (8.59 S m ), and excellent sensing performance investigated three types of programmable metamaterials:
-1
[40]
(S = 0.051 kPa and GF = 2.9). It can be applied in tissue triangular, square, and honeycomb lattice metamaterials .
-1
engineering and other fields. The second trend identified Results found that the metamaterials with triangular and
was the combination of SMMs to improve operation cycles, square lattices underwent large deformations and auxetic
recovery rate, toughness, etc. . Pyo et al. (2018) integrate behavior, and their Poisson’s ratios and elastic modulus
[34]
an SMA with an SMP to obtain a shape memory composite can be programmed by adjusting the topical parameters
(SMC). The volume fraction of SMA:SMP of 1:5 was found and temperature. This material can be used in biomedical
[40]
to be the optimum ratio for good operation cycles, giving the scaffolds . The fourth trend concerns the fabrication of
largest length change (8 mm) and the fastest response (4 s). innovative inks. As previously mentioned, SRMs
The results were favorable for the applications of stents and for 4D applications are categorized into temperature-
valve controllers . According to Bodkhe and Ermanni , responsive materials, pH-responsive materials, moisture-
[35]
[36]
it should be as poly-lactic acid (PLA) and polyesteramide responsive materials, electric and magnetic field-responsive
(PEA) and piezoelectric barium titanate nanoparticles. This materials, light-responsive materials, acoustic-responsive
SMC has a recovery rate of approximately 98% and a linear materials, and multiple stimuli-responsive materials.
response in the force range of 0.1–1 N. This material can Ashammakhi et al. (2018) studied potential bioinks for
Volume 9 Issue 6 (2023) 191 https://doi.org/10.36922/ijb.1112