Legumain-triggered aggregable gold nanoparticles for enhanced intratumoral retention

Insufficient intratumoral retention of nanomedicines remains the major challenge for broad implementation in clinical sets.Herein,we proposed a legumain-triggered aggregable gold nanoparticle(GNP)delivery platform(GNPs-A&C).GNPs-A&C could form intratumoral or intracellular aggregates in response to the overexpressed legumain.The aggregates with size increase not only could reduce back-flow from interstitial space to peripheral bloodstream but also could restrict the cellular exocytosis,leading to enhanced intratumoral retention.In vitro studies demonstrated that GNPs-A&C possessed an excellent legumain responsiveness and the increased size was closely relevant with legumain expression.In vivo studies demonstrated GNPs-A&C possessed slower clearance rate and much higher intratumoral retention within legumain-overexpressed tumor compared to non-aggregable NPs,regardless of intravenous or intratumoral injection.More importantly,this delivery platform significantly improved the chemotherapeutic effect of doxorubicin(DOX)towards subcutaneous xenograft C6 tumor.The effectiveness of this stimulus-responsive aggregable delivery system provides a thinking for designing more intelligent size-tunable nanomedicine that can substantially improve intratumoral retention.

Bioresponsive micro-to-nano albumin-based systems for targeted drug delivery against complex fungal infections

As a typical human pathogenic fungus,Cryptococcus neoformans is a life-threatening invasive fungal pathogen with a worldwide distribution causing w700,000 deaths annually.Cryptococcosis is not just an infection with multi-organ involvement,intracellular survival and extracellular multiplication of the fungus also play important roles in the pathogenesis of C.neoformans infections.Because adequate accumulation of drugs at target organs and cells is still difficult to achieve,an effective delivery strategy is desperately required to treat these infections.Here,we report a bioresponsive micro-to-nano(MTN)system that effectively clears the C.neoformans in vivo.This strategy is based on our in-depth study of the overexpression of matrix metalloproteinase 3(MMP-3)in infectious microenvironments(IMEs)and secreted protein acidic and rich in cysteine(SPARC)in several associated target cells.In this MTN system,bovine serum albumin(BSA,a natural ligand of SPARC)was used for the preparation of nanoparticles(NPs),and then microspheres were constructed by conjugation with a special linker,which mainly consisted of a BSA-binding peptide and an MMP-3-responsive peptide.This MTN system was mechanically captured by the smallest capillaries of the lungs after intravenous injection,and then hydrolyzed into BSA NPs by MMP-3 in the IMEs.The NPs further targeted the lung tissue,brain and infected macrophages based on the overexpression of SPARC,reaching multiple targets and achieving efficient treatment.We have developed a size-tunable strategy where microspheres"shrink"to NPs in IMEs,which effectively combines active and passive targeting and may be especially powerful in the fight against complex fungal infections.