Boosting the photocatalytic performance of Ag_2CO_3 crystals in phenol degradation via coupling with trace N-CQDs

A series of N‐CQDs/Ag2CO3composite crystals(where N‐CQDs=Nitrogen doped carbon quantumdots)were prepared by adding different volumes of a solution of N‐CQDs during Ag2CO3crystalgrowth.Under irradiation from a350‐W Xe lamp light(with optical filter,λ≥420nm),the performanceof N‐CQDs/Ag2CO3in photocatalytic degradation of phenol was evaluated.The as‐preparedsamples were analyzed by XRD,SEM,TEM,BET,element mapping,UV‐vis DRS,FT‐IR,XPS,transientphotocurrent response and EIS testing.The results showed that after coupling with trace amountsof N‐CQDs,both the photocatalytic activity and stability of Ag2CO3were greatly boosted.The additionof N‐CQDs solution influenced the crystallization of Ag2CO3,resulting in a distinct decrease inAg2CO3crystal size and an obvious increase in surface area.Moreover,the charge transfer resistancewas greatly reduced,and the separation efficiency of photogenerated electrons and holes wasstrongly promoted.The presence of NCQDs on the surface of the catalysts facilitates the transfer ofphotogenerated electrons,slowing the photocorrosion rate of Ag2CO3,and then resulting in higherstability than bare Ag2CO3in degradation.The synergistic effect of the improvement of morphologyand charge transfer rate thus accounted for the superior photocatalytic performance ofN‐CQDs/Ag2CO3.

Amphipathicity mediated endocytosis of mesoporous silica nanoparticles with tunable frameworks

Due to the amphiphilic nature of phospholipids in the cell membrane,the amphipathicity of the nanomedicine plays a crucial role in the endocytosis.However,limited biological characterization methods restrict the study of the state of nanoparticles with different amphiphilicities on cell membranes.The understanding of interaction of amphiphilic particle with cell membrane is still lacking.Herein,by combining the dissipative particle dynamics(DPD)with the framework construction of mesoporous silica nanoparticles(MSNs),we demonstrate the enhanced endocytosis induced by the hydrophobicity.DPD results confirm that the presence of hydrophobic groups on the surface of nanoparticles can disturb the integrity of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine(POPC)membrane and induce activation of phospholipids to a higher energy level,thereby facilitating the wrapping of nanoparticles.To validate the simulation findings,uniform MSNs with hydrophilic pure silica framework and two types of amphiphilic MSNs with varying hydrophilic organic groups in the framework are rationally synthesized by using different silane precursors.The obtained three kinds of MSNs show similar diameter(~100 nm)and mesopores(~2 nm),but distinct hydrophobicity/hydrophilicity ratio.The phenyl-bridged MSN with a carbon content of 27.1%exhibits enhanced cellular uptake,consistent with the theoretical simulation results.This work sheds light on how the surface amphipathicity influences endocytosis through the interaction with cell membrane.

Spatially asymmetric cascade nanocatalysts for enhanced chemodynamic therapy

Chemodynamic therapy(CDT)based on cascade catalytic nanomedicine has emerged as a promising cancer treatment strategy.However,most of the reported cascade catalytic systems are designed based on symmetric-or co-assembly of multiple catalytic active sites,in which their functions are difficult to perform independently and may interfere with each other.Especially in cascade catalytic system that involves fragile natural-enzymes,the strong oxidation of free-radicals toward natural-enzymes should be carefully considered,and the spatial distribution of the multiple catalytic active sites should be carefully organized to avoid the degradation of the enzyme catalytic activity.Herein,a spatially-asymmetric cascade nanocatalyst is developed for enhanced CDT,which is composed by a Fe_(3)O_(4)head and a closely connected mesoporous silica nanorod immobilized with glucose oxidase(mSiO_(2)-GOx).The mSiO_(2)-GOx subunit could effectively deplete glucose in tumor cells,and meanwhile produce a considerable amount of H_(2)O_(2)for subsequent Fenton reaction under the catalysis of Fe_(3)O_(4)subunit in the tumor microenvironment.Taking the advantage of the spatial isolation of mSiO_(2)-GOx and Fe_(3)O_(4)subunits,the catalysis of GOx and freeradicals generation occur at different domains of the asymmetric nanocomposite,minimizing the strong oxidation of free-radicals toward the activity of GOx at the other side.In addition,direct exposure of Fe_(3)O_(4)subunit without any shelter could further enhance the strong oxidation of free-radicals toward objectives.So,compared with traditional core@shell structure,the long-term stability and efficiency of the asymmetric cascade catalytic for CDT is greatly increased by 138%,thus realizing improved cancer cell killing and tumor restrain efficiency.

Highly stable hybrid single-micelle:A universal nanocarrier for hydrophobic bioimaging agents

As the first-line technology,micelles play a pivotal role in in vivo delivery of theranostic agents because of their high biocompatibility and universality.However,in complex physiological environments(extreme dilution,pH,and oxidation or reduction,etc.),they generally suffer from structural instability and insufficient protection for encapsulated cargos.It is urgent to reinforce the structural stability of the micelles at the single-micelle level.By using the FDA-approved Pluronic F127 surfactants and indocyanine green(ICG)bioimaging agents as model,herein,we propose the silane-crosslinking assisted strategy to reinforce the structural stability of the single-micelle.Different from the traditional silane hydrolysis under the harsh experimental conditions(acidic,alkaline,and high temperature hydrothermal,etc.),the ICG loaded F127@SiO_(2) hybrid single-micelles(ICG@H-micelles)with controllable sizes(15-35 nm)are synthesized at neutral pH and room temperature,which is crucial for the maintenance of the physicochemical properties of the encapsulated cargos.With the ultra-thin SiO_(2)(<5 nm)at hydrophilic layer of the single-micelle,the structural and fluorescence stability of ICG@H-micelles are much higher than the conventional micelle(ICG@micelles)in the simulated physiological environments of dilution,oxidation or reduction,and low pH.Because of the high structural and fluorescence stability,the ICG@H-micelles also exhibit longer duration time in the tumor and gastrointestinal tract bioimaging.