Speaker
Description
"Biological organisms have been a source of inspiration for the development of high-performance materials. Particularly, the optimized physical adhesion between pollen grains and bees’ leg hair during the pollination process, where pollen grains diameter matches the distance between the bees' hair, has encouraged the development of an optimized biomimetic drug dressing. After satisfactory results using polydimethylsiloxane (PDMS) in a proof-of-concept study1, we now propose the fabrication of a natural-derived micropatterned hydrogel patch made of laminarin, a marine polysaccharide found in brown algae.
The fabrication of such improved hydrogel patch relies on a double biomimetic process, that combines the naturally optimized process made by bees and the natural mussels’ adhesion in wet environments2,3, to ameliorate the properties of the drug patches, particularly in terms of drug content and improved adhesiveness.
Hence, in order to enhance the patch adhesion to the wet environment of the wound, while enhancing its mechanical performance, laminarin was modified with hydroxypyridinone (HOPO) groups in its backbone and conjugated with titanium dioxide nanoparticles. Such nanoparticles also present promising effects on the wound healing process through antimicrobial effects and cell growth stimulation.4
Then, the patch was microfabricated by allying soft lithography and UV-irradiation, resulting in a membrane with micropillars with high aspect-ratio. Based on the previous observation that higher particle entrapment is achieved when the particles’ diameter matched the distance between the micropillars, a drug patch was assembled in two different approaches by using ciprofloxacin either i) in the powder form or ii) encapsulated into alginate beads. Release studies demonstrated that a rapid release is achieved during the first hours, following a more controlled release over time for both hierarchical systems: patch enclosing free drug or drug-loaded microparticles. Additionally, the antibacterial activity against gram-negative and gram-positive bacteria was also investigated, where the laminarin patch without drug content showed inherent antibacterial activity against Escherichia coli, which represents an added value for our drug-delivery patches. Withal, the introduction of drug particles increased the antibacterial activity for both conditions. In addition, the biocompatibility of the patch with human dermal fibroblasts was attested up to 14 days of culture. Overall, we herein proposed the fabrication of a novel hydrogel patch able to overcome the current challenges of wound dressings, namely i) poor mechanical properties, ii) limited adhesiveness, iii) poor biocompatibility, iv) lack of prolonged antimicrobial activity and v) limited drug dosage. We envision that the developed micropatterned devices can be explored in the biomedical field and be applied in situations that require the topical administration of high quantity of drug, enabling less-frequent dosing, thus significantly improving patient’s compliance.
- Santos, L.F. et al., PNAS. 116(12):5405-5410(2019).
- Amador, G.J. et al., Bioinspir Biomim. 12:1-11(2017).
- Gomes, M.C. et al., Adv Healthc Mater. 10(19):1-9(2021).
- Nikpasand, A. et al., Bull Emerg Trauma. 7(4):366-372(2019)."
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