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Materials Science in Additive Manufacturing Fibrous silk in biomedicine

to synthetic materials such as polyether ether ketone demonstrated excellent bone regeneration. FS also exhibits
or Kevlar. Regenerated FS materials, such as films or significant advantages in tendon, ligament, and soft tissue
solution-derived scaffolds, demonstrate even poorer regeneration. For example, Zhou et al. applied FS/CPC
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mechanical performance (elongation at break <2%) due composites to treat rabbit radial bone defects and, after
to the disruption of native secondary structures during 4 weeks, observed new trabecular bone formation with
processing. Although advanced techniques such as significantly improved mechanical properties compared to
genetic engineering and nanocomposite reinforcement the control group. In another study, Fan et al. used FS
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(e.g., graphene enhancement) have shown promise in scaffolds loaded with MSCs to repair ACL in pigs. After
improving FS performance, the complexity and cost of 24 weeks, the regenerated ligament exhibited collagen
large-scale manufacturing remain substantial barriers to alignment and mechanical strength comparable to that of
clinical translation. natural tissue. Li et al. developed ε-polylysine-modified
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Although degummed FS is generally considered FS membranes that demonstrated excellent antibacterial
immunologically inert, residual sericin or degradation and wound-healing properties in animal models, without
fragments can still elicit mild inflammatory responses. the need for antibiotics.
The long-term toxicity of FS in the human body remains Optimizing the mechanical properties, degradation rates,
insufficiently characterized, particularly in cases involving and biological activity of FS materials through biofunctional
prolonged implantation, where degradation fragments modifications, composite strategies, and tailored designs
may trigger chronic inflammation, fibrosis, or amyloid for specific medical applications has expanded their
deposition. Most current in vivo studies are limited to potential in bone repair, nerve regeneration, and skin
small animal models – such as rodents (mice and rats) and wound healing. However, future research should focus on
rabbits – with experimental durations typically spanning designing application-specific FS-based biomaterials and
several weeks to months, focusing primarily on early-stage conducting long-term in vivo studies in large animal models
tissue regeneration. For example, Fan et al. conducted a to comprehensively evaluate their safety and effectiveness,
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24-week study using FS scaffolds for ACL repair in pigs, thereby supporting clinical translation.
while Zhou et al. reported bone regeneration outcomes
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after just 4 weeks. Although these studies support the initial Advancements in AM and 3D printing technologies
biocompatibility and regenerative potential of FS, longer- will be critical for enhancing FS’s mechanical properties,
term experimental data (e.g., over 1 year), especially from structural design, and bioactivity. Integrating FS with
large animal models such as goats or dogs, remain scarce. other biomaterials (such as hydrogels, nanomaterials,
Therefore, further exploration of the long-term safety and polycaprolactone, or graphene) can yield multifunctional
toxicity of FS in the human body is essential. composites with enhanced clinical performance.
Furthermore, the precision enabled by 3D printing
Standardization and certification of FS materials facilitates the development of personalized implants and
for medical applications present additional challenges, smart medical devices (such as electronic textiles) based
particularly within the context of AM technologies. The on FS, providing tailored solutions across clinical needs.
lack of a unified regulatory framework contributes to This approach can expand FS’s applications in tissue
prolonged and complex approval processes. In addition, engineering, drug delivery, wound healing, and smart
natural silk production is subject to biological variability healthcare technologies.
due to differences in silkworm species and breeding
conditions, leading to inconsistent material quality. 7. Conclusion
While the incorporation of FS with other materials (such
as conductive carbon nanotubes or growth factors) can FS has emerged as a highly versatile biomaterial due
enhance functionality, the long-term compatibility and to its unique combination of mechanical strength,
stability of these multi-material interfaces require further biocompatibility, tunable biodegradability, and
optimization. For instance, silver nanoparticle-loaded FS antimicrobial activity. This review systematically examined
dressings may exhibit diminished antibacterial efficacy the structure, properties, and biomedical applications
over time due to uneven silver ion release. of FS, with a special focus on its integration with AM
technologies for tissue engineering, wound healing,
6.2. Future prospects of FS-based biomaterials and regenerative medicine. FS-based materials have
FS materials offer substantial potential for clinical demonstrated promising results in pre-clinical models
translation, as evidenced by promising results in various for the regeneration of skin, cartilage, tendon, ligament,
animal models. Studies utilizing FS combined with vasculature, and bone. Despite these advances, several
CPC composites for rabbit bone defect repair have limitations remain, including the need for improved

Volume 4 Issue 2 (2025) 17 doi: 10.36922/MSAM025130020