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International Journal of Bioprinting Transdermal vitamin C delivery by MNPs

there still remain some challenges in the fabrication of treatment area to the surrounding skin, supporting the
MNPs. As a typical example of subtractive manufacturing findings of our previous research.
process, the existing sheet-cutting is a complex process, Taken together, MNPs have broad application
which usually produces MNPs with rough structure. prospects in the fields of disease prevention, treatment,
Formative manufacturing of MNPs usually refers to and cosmetology. This study illustrates a new strategy
micromolding. Since the mold is prefabricated, filled, and for skin photoprotection, based on the reliable
demolded, this manufacturing method requires a plethora transdermal vitamin C delivery capabilities of MNPs.
of steps and is difficult to customize. Overall, conventional Future works will focus on testing the MNPs on human
subtractive manufacturing and formative manufacturing subjects, evaluating their long-term effects and safety,
methods are more cumbersome, time-consuming, and and exploring their compatibility with other drugs or
labor-intensive, in addition to their challenges in the substances.
customization of MNPs. Thus, the clinical translation of
MNPs is restricted by fabrication technologies. 5. Conclusion
Additive manufacturing provides a powerful This study utilized a DLP-based micro-printing process to
manufacturing technology for fabricating personalized rapidly and accurately fabricate high-quality MNPs, which
structures. 37,38 Aiming at the problems of how to precisely can enhance the topical delivery of vitamin C and alleviate
fabricate MNPs in batches, we designed a type of skin photodamage painlessly. Thus, MNPs-assisted
polymeric MNP prepared by DLP-based micro-printing transdermal delivery of vitamin C is a promising strategy
process. Compared with the traditional sheet-cutting and for alleviating skin photodamage.
micromolding methods, our study highlights the advantages
of MNPs fabricated through DLP-based micro-printing, Acknowledgments
including precise customization, cost-effectiveness, and We thank Boya Li for the assistance in paper writing and
efficient batch manufacturing. Customized micro-printing language. We thank H. Wang from the Analytical and
can easily design the pattern of MNP, which can be flexibly Testing Center, Sichuan University, P. R. China, for the
adjusted according to different situations. Regarding high- SEM observation and analysis of the data.
precision fabrication, high resolution below 5 μm was
achieved using a modified micro-lens and multiple MNPs Funding
can be rapidly printed by a single exposure. Therefore, This work was supported by National Key Research and
this process lays a solid foundation for the clinical Development Program of China (2021YFF1200800),
transformation of MNPs in the future. Sichuan Science and Technology Program (2021JDTD0001,

According to the process, we could obtain high-quality 2022YFQ0004), Fundamental Research Funds for the
MNPs with smooth surface and reliable mechanical Central Universities (2022SCU12046), and National
properties. Simulated RB drug delivery showed that the Natural Science Foundation of China (82073473).
efficiency of the MNPs-assisted group can be increased
by several folds compared with that of the control group, Conflict of interest
indicating that low-permeability macromolecular or The authors declare no conflicts of interest.
water-soluble topical drugs can be applied using the
MNPs-assisted drug delivery approach. Author contributions

MNPs insertion avoids touching blood vessels and Conceptualization: Li Zhang, Maling Gou
nerves, thus causing no pain or bleeding. They create Investigation: Li Zhang, Haofan Liu, Linghong Guo
micron-scale holes, through which pharmaceutical Xuebing Jiang, Siyi Wang, Run Tian, Yiting Huang
preparations applied to the skin surface can diffuse into the Project administration: Maling Gou, Xian Jiang
body. The skin healed well after the MNPs puncture, and Writing – original draft: Li Zhang
there were no residual projections in the skin after treatment, Writing – review & editing: Maling Gou, Li Zhang
which can significantly avoid the risk of infection. In the
mice model, the MNPs were used to improve the efficacy of Ethics approval and consent to participate
vitamin C, providing a new stratagem for alleviating skin All animal protocols were carried out according to the
photodamage. ROS in the skin near the treated area could Institutional Ethical Guidelines on animal care and
be efficiently removed by vitamin C. We could clearly approved by the Ethics Committee of West China Hospital,
observe that the therapeutic effect radiated from the round Sichuan University (20230113007).

Volume 10 Issue 1 (2024) 366 https://doi.org/10.36922/ijb.1285