No abstract

Biological application of chiral nanoparticles (NPs) has aroused enormous levels of attention over recent years. Here, we synthesized magneto-chiral cobalt hydroxide (Co(OH) 2 ) NPs that exhibited strong chiroptical and unique magnetic properties and applied these NPs to detect and monitor reactive oxygen species (ROS) in living cells and in vivo. Circular dichroism (CD) and magnetic resonance imaging (MRI) signals of the magneto-chiral Co(OH) 2 NPs exhibited a wide intracellular ROS detection range from 0.673 to 612.971 pmol/10 6 cells with corresponding limits of detection (LOD) at 0.087 and 0.179 pmol/10 6 cells, far below that of currently available probes; the LOD for D-aspartic acid coated Co(OH) 2 NPs (D-Co(OH) 2 NPs) was 5.7 times lower than that for L-aspartic acid coated Co(OH) 2 NPs (L-Co(OH) 2 NPs) based on the CD signals. In addition, D-Co(OH) 2 NPs also exhibited dynamic ROS monitoring ability. The high levels of selectivity and sensitivity to ROS in complex biological environments can be attributed to the Co 2+ oxidation reaction on the surface of the NPs. Furthermore, magneto-chiral Co(OH) 2 NPs were able to quantify the levels of ROS in living mice by fluorescence and MRI signals. Collectively, these results reveal that magneto-chiral Co(OH) 2 NPs exhibit a remarkable ability to quantify ROS levels in living organisms, and could therefore provide new tools for exploring chiral nanomaterials as a potential biosensor to investigate biological events.

Cellular senescence is stress-induced, irreversible growth arrest, and is thought to impair tissue function. The clearance of senescent cells can delay the features of senescence.Herein, we report the development of plasmonic coreshell spikyn anorods (CSNRs) surface-modified with an antibeta-2-microglobulin (aB2MG) antibody and triphenylphosphonium (TPP), to target the mitochondria in senescent cells. aB2MG-TPP@CSNRs irradiated with near-infrared (NIR) light selectively caused mitochondrial damage and apoptosis of senescent cells with relatively low NIR light power,a nd the ability of CSNRs to activate and amplify the immune response in vitro and in vivo was discovered. The photo-induced generation of reactive oxygen species (ROS) resulted in senescentcell apoptosis and immune adjuvant effect by CSNRs accelerated the clearance of senescent cells in mice.This study opens the wayf or the use of precisely regulated plasmonic nanostructures for immune adjuvant and photo-induced apoptosis for age-related senescence.

One of the most common methods to treat thromboembolism is the use of thrombolytic drugs to activate fibrinolytic protease.T he aim of this treatment was to initiate the lysis of fibrin;h owever,t here are many side-effects associated with this form of treatment. Herein, we fabricated chiral Co 3 O 4 supraparticles (SPs) with ag-factor of up to 0.02 at 550 nm and paramagnetic performance applied in the treatment of thromboembolism under an electromagnetic field (MF). In vitro experiments showed that d-SPs degraded blood clot within 8hours under MF.C ompared to l-SPs, d-SPs exhibited muchs tronger thrombolytic ability and effectively enhanced the survival rate of thrombosis model mice more than 70 %inthe 25 dofobservation. The results of mechanism study showed that under MF,t he level of reactive oxygen species (ROS) produced by d-SPs were 1.5 times higher than that of l-SPs,w hichm ight be attributed to the chiral-induced spin selectivity effects. Scheme 1. A) Illustration of chiral Co 3 O 4 SPs@PM preparation process and B) underlying mechanism of thrombolysis therapy by chiral Co 3 O 4 SPs@PM.