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Smart MOF coating enables stimuli-responsive drug release
A new multifunctional coating combining a MOF membrane with a temperature- and pH-responsive copolymer offers magnesium implants effective corrosion protection together with on-demand drug release controlled by physiological stimuli.
Magnesium-based implants are attractive for biomedical applications due to their biodegradability and mechanical compatibility with bone, but their rapid and uncontrolled corrosion in physiological media remains a critical hurdle for clinical translation. Researchers Tao, Qi and colleagues have now engineered a multifunctional coating that combines corrosion protection with stimuli-responsive drug release, addressing both challenges simultaneously.
The team synthesised a temperature- and pH-responsive poly(N-isopropylacrylamide-co-acrylic acid) copolymer (PNIPA-AA) and covalently grafted it onto a UiO-66-NH₂ metal–organic framework membrane on magnesium substrates. The resulting UiO-66-PNIPA-AA coating provides effective corrosion protection, efficient photothermal conversion and favourable cyto- and haemocompatibility.
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Intelligent drug release through dual stimuli
The PNIPA-AA networks regulate drug release through a combination of steric hindrance and hydrogen bonding. Under physiological conditions of 37 °C and pH 7–8, the polymer chains extend to form a crosslinked diffusion barrier that suppresses drug leakage. When temperature rises to 42 °C or pH decreases to 5, the chains collapse, disrupting the network and enabling diffusion-controlled drug release.
This dual-responsive mechanism enables targeted, on-demand drug delivery in response to inflammation or photothermal stimulation, while the underlying coating maintains barrier protection of the magnesium substrate. The approach offers a versatile platform for the design of intelligent biodegradable implants combining corrosion resistance with precisely controlled therapeutic functionality.
Source: Tao, Y. et al., Multifunctional MOF-based coating on magnesium enabling integrated properties of corrosion protection, biocompatibility and stimuli-responsive drug release. Progress in Organic Coatings (2026), https://doi.org/10.1016/j.porgcoat.2026.110228.
