Soft Mesoporous Organosilica Nanoplatforms Improve Blood Circulation,Tumor Accumulation/Penetration,and Photodynamic Efficacy

To date,the ability of nanoplatforms to achieve excellent therapeutic responses is hindered by short blood circulation and limited tumor accumulation/penetration.Herein,a soft mesoporous organosilica nanoplatform modified with hyaluronic acid and cyanine 5.5 are prepared,denoted SMONs-HA-Cy5.5,and comparative studies between SMONs-HA-Cy5.5(24.2 MPa)and stiff counterparts(79.2 MPa)are conducted.Results indicate that,apart from exhibiting a twofold increase in tumor cellular uptake,the soft nanoplatforms also display a remarkable pharmacokinetic advantage,resulting in considerably improved tumor accumulation.Moreover,SMONs-HA-Cy5.5 exhibits a significantly higher tumor penetration,achieving 30-μm deeper tissue permeability in multicellular spheroids relative to the stiff counterparts.Results further reveal that the soft nanoplatforms have an easier extravasation from the tumor vessels,diffuse farther in the dense extracellular matrix,and reach deeper tumor tissues compared to the stiff ones.Specifically,the soft nanoplatforms generate a 16-fold improvement(43 vs.2.72μm)in diffusion distance in tumor parenchyma.Based on the significantly improved blood circulation and tumor accumulation/penetration,a soft therapeutic nanoplatform is constructed by loading photosensitizer chlorin e6 in SMONs-HA-Cy5.5.The resulting nanoplatform exhibits considerably higher therapeutic efficacy on tumors compared to the stiff ones.

Effect of the structure of ginsenosides on the in vivo fate of their liposomes

To utilize themultiple functions and give full play of ginsenosides,a variety of ginsenosides with different structures were prepared into liposomes and evaluated for their effect on the stability,pharmacokinetics and tumor targeting capability of liposomes.The results showed that the position and number of glycosyl groups of ginsenosides have significant effect on the in vitro and in vivo properties of their liposomes.The pharmacokinetics of ginsenosides liposomes indicated that the C-3 sugar group of ginsenosides is beneficial to their liposomes for longer circulation in vivo.The C-3 and C-6 glycosyls can enhance the uptake of their liposomes by 4T1 cells,and the glycosyls at C-3 position can enhance the tumor active targeting ability significantly,based on the specific binding capacity to Glut 1 expressed on the surface of 4T1 cells.According to the results in the study,ginsenoside Rg3 and ginsenoside Rh2 are potential for exploiting novel liposomes because of their cholesterol substitution,long blood circulation and tumor targeting capabilities.The results provide a theoretical basis for further development of ginsenoside based liposome delivery systems.

Drug carriers based on highly protein-resistant materials for prolonged in vivo circulation time

Long-circulating drug carriers are highly desirable in drug delivery system.However,nonspecific protein adsorption leaves a great challenge in drug delivery of intravenous administration and significantly affects both the pharmacokinetic profiles of the carrier and drugs,resulting in negatively affect of therapeutic efficiency.Therefore,it is important to make surface modification of drug carriers by protein-resistant materials to prolong the blood circulation time and increase the targeted accumulation of therapeutic agents.In this review,we highlight the possible mechanism of protein resistance and recent progress of the alternative protein-resistant materials and their drug carriers,such as poly(ethylene glycol),oligo(ethylene glycol),zwitterionic materials,and red blood cells adhesion.

Hypoxia-degradable and long-circulating zwitterionic phosphorylcholine-based nanogel for enhanced tumor drug delivery

Tumor microenvironment has been widely utilized for advanced drug delivery in recent years,among which hypoxia-responsive drug delivery systems have become the research hotspot.Although hypoxia-responsive micelles or polymersomes have been successfully developed,a type of hypoxia-degradable nanogel has rarely been reported and the advantages of hypoxia-degradable nanogel over other kinds of degradable nanogels in tumor drug delivery remain unclear.Herein,we reported the synthesis of a novel hypoxia-responsive crosslinker and the fabrication of a hypoxia-degradable zwitterionic poly(phosphorylcholine)-based(HPMPC)nanogel for tumor drug delivery.The obtained HPMPC nanogel showed ultra-long blood circulation and desirable immune compatibility,which leads to high and long-lasting accumulation in tumor tissue.Furthermore,HPMPC nanogel could rapidly degrade into oligomers of low molecule weight owing to the degradation of azo bond in hypoxic environment,which leads to the effective release of the loaded drug.Impressively,HPMPC nanogel showed superior tumor inhibition effect both in vitro and in vivo compared to the reduction-responsive phosphorylcholine-based nanogel,owing to the more complete drug release.Overall,the drug-loaded HPMPC nanogel exhibits a pronounced tumor inhibition effect in a humanized subcutaneous liver cancer model with negligible side effects,which showed great potential as nanocarrier for advanced tumor drug delivery.

Nanocapsules of oxalate oxidase for hyperoxaluria treatment

Enzyme therapeutics have great potential for the treatment of systemic disorders such as urolithiasis and nephrocalcinosis, which are caused by the excessive accumulation of oxalate. However, exogenous enzymes have short half-lives in vivo and elicit high immunogenicity, which largely limit the therapeutic outcomes. Herein, we report a delivery strategy whereby therapeutic enzymes are encapsulated within a thin zwitterionic polymer shell to form enzyme nanocapsules. The strategy is exemplified by the encapsulation of oxalate oxidase （OxO） for the treatment of hyperoxaluria, because as-synthesized OxO nanocapsules have a prolonged blood circulation half-life and elicit reduced immunogenicity. Our design of enzyme nanocapsules that enable the systemic delivery of therapeutic enzymes can be extended to various biomedical applications.