A biomimetic upconversion nanoreactors for near-infrared driven H2 release to inhibit tauopathy in Alzheimer’s disease therapy

Abnormal hyperphosphorylation of tau protein is a principal pathological hallmark in the onset of neurodegenerative disorders,such as Alzheimer’s disease(AD),which can be induced by an excess of reactive oxygen species(ROS).As an antioxidant,hydrogen gas(H_(2))has the potential to mitigate AD by scavenging highly harmful ROS such as·OH.However,conventional administration methods of H_(2) face significant challenges in controlling H_(2) release on demand and fail to achieve effective accumulation at lesion sites.Herein,we report artificial nanoreactors that mimic natural photosynthesis to realize near-infrared(NIR)light-driven photocatalytic H_(2) evolution in situ.The nanoreactors are constructed by biocompatible crosslinked vesicles(CVs)encapsulating ascorbic acid and two photosensitizers,chlorophyll a(Chla)and indoline dye(Ind).In addition,platinum nanoparticles(Pt NPs)serve as photocatalysts and upconversion nanoparticles(UCNP)act as light-harvesting antennas in the nanoreacting system,and both attach to the surface of CVs.Under NIR irradiation,the nanoreactors release H_(2) in situ to scavenge local excess ROS and attenuate tau hyperphosphorylation in the AD mice model.Such NIR-triggered nanoreactors provide a proof-of-concept design for the great potential of hydrogen therapy against AD.

Plasmon-enhanced FRET biosensor based on Tm^(3+)/Er^(3+)co-doped core-shell upconversion nanoparticles for ultrasensitive virus detection

Outbreaks of infectious viruses offer a formidable challenge to public healthcare systems and early detection of viruses is essential for preventing virus propagation.In this work,an ultrasensitive plasmon-enhanced fluorescence resonance energy transfer(FRET)biosensor based on core-shell upconversion nanoparticle(csUCNP)and gold nanoparticle(AuNP)for accurate detection of SARS-CoV-2 viral RNA is presented.In this biodetection assay,the Tm^(3+)/Er^(3+)co-doped csUCNP NaGdF_(4):Yb/Tm@NaYF_(4):Yb/Er acts as an energy donor and AuNP serves as an energy acceptor.The upconversion emission of Tm^(3+)and the design of the core-shell structure led to a simultaneous surface plasmon effect of AuNP.The localized surface plasmon resonance(LSPR)arising from collective oscillations of free electrons significantly enhanced FRET efficiency between Er^(3+)and AuNP.The as-prepared biosensor obtained a limit of detection(LOD)as low as 750 aM,indicating that the integration of FRET and surface plasmon into one biodetection assay significantly boosted the sensitivity of the biosensor.In addition,samples extracted from clinical samples are also utilized to validate the effectiveness of the biosensor.Therefore,this innovative plasmon-enhanced FRET biosensor based on Tm^(3+)/Er^(3+)co-doped csUCNP may pave the way for rapid and accurate biodetection applications.