Intracellular Delivery Of Itaconate By Metal–Organic Framework-Anchored Hydrogel Microspheres For Osteoarthritis Therapy

Osteoarthr it is(OA)remains a ma jor clinical challenge that is difficult to solve.Itaconate(IA),an emerging regula tor of intracellu lar inflammat ion and oxidat ive stress,may potent ially be har nessed to treat OA.However,the short jo int residence t ime,ineffic ient drug deliver y,and cell-imper meable property o f I A can ser iously hamp er the clinical translat io n.Objective: We prepared zeo lit e imidazole framework-8 nanoparticles coated with I A(IA-ZI F-8).IA-ZI F-8 nanoparticles wer e fir mly immo bilized in hydrogel microspheres via micro fluidic techno logy,achieve slow release of drug-loaded nanopart icles in the jo int cavit y.T he p H responsiveness based on IA-ZI F-8 achieves sustained intracellular release of IA,and explores the ther apeut ic effect of I A-ZI F-8@HMs on knee OA.Methods:(1)Zeolite imidazo le frame work-8(IA-ZIF-8)nanoparticles wrapped wit h I A were prepared by zinc ion,2-methylimidazo le and I A self-assembly,making it p H-responsive.Subsequent ly,hydrogel microspheres HMs were prepared by microfluidic techno logy and IA-ZI F-8nanopart icles were fir mly fixed in hydrogel mi crospheres(IA-ZI F-8@HMs).They were character ized by transmissio n electron microscopy,Zetasizer Nano ZSE(Malver n),and X-ray diffracto metry.(2)ADTC-5 cells were used as a model to invest igate the cytotoxicit y of drug-loaded microspheres and the intracellular uptake of nanoparticles(IA-ZIF-8).(3)IL-1β was used to mimic the infla mmatory microenvironment in OA progressio n,and the levels of TNF-α and IL-6 in cell cultur e supernatants were detected by enzyme-linked immunosorbent assay(ELIS A).(4)A rat knee jo int OA model was established to stud y the therapeut ic effect of drug-loaded microspheres(IA-ZI F-8@HMs)in OA.Results:(1)We successfully prepared I A-ZIF-8 and ZI F-8,wit h part icle sizes of 79.57 ± 7.89 nm and 43.62 ± 3.59 nm,respect ively.I A-ZI F-8 was found to have acid responsiveness characterist ics.We have successfully prepared hydrogel microspheres(HMs)that show smoothness and unifor m size.I mmo bilizat ion of IA-ZIF-8 in hydrogel microspheres for ms a micron-scale co mposite mater ial(I A-ZIF-8@HMs).(2)Live/dead staining and MTT exper iments ver ified that IA-ZIF-8@HMs has litt le toxicit y to AT DC 5 cells.Cell uptake exper iments have ver ified that nanoparticles can be ingested into cells and disintegrated by lysoso mal destruct ion.IA-ZI F-8@HMs per for med well in oxidative stress and in reducing inflammator y cytokine(i.e.,TNF-α and IL-6)levels.(3)Animal exper iments showed that IA-ZI F-8@HMs can effect ively dela y the progressio n of osteoarthr it is in MI A-induced knee osteoarthr it is in rats.Conclusion: We inno vat ively constructed injec table mo nodisper se hydrogel microspheres using micro fluid ic techno logy and successfu lly loaded I A-ZI F-8@HMs,slowly releasing IA-ZIF-8 nanoparticles.I n vitro cell exper iments,oxidat ive stress and ant i-inflammatory effects are more obvio us.Animal exper iments have shown that IA-ZI F-8@HMs has a lo ng-ter m effect ive therapeut ic effect in rat OA models.