Chemodynamic therapy based on Fe 2+ -catalyzed Fenton reaction holds great promise in cancer treatment. However, low-produced hydroxyl radicals in tumor cells constitute its severe challenges because of the fact that Fe 2+ with high catalytic activity could be easily oxidized into Fe 3+ with low catalytic activity, greatly lowering Fenton reaction efficacy. Here, we codeliver CuS with the iron-containing prodrug into tumor cells. In tumor cells, the overproduced esterase could cleave the phenolic ester bond in the prodrug to release Fe 2+ , activating Fenton reaction to produce the hydroxyl radical. Meanwhile, CuS could act as a nanocatalyst for continuously catalyzing the regeneration of high-active Fe 2+ from low-active Fe 3+ to produce enough hydroxyl radicals to efficiently kill tumor cells as well as a photothermal therapy agent for generating hyperthermia for thermal ablation of tumor cells upon NIR irradiation. The results have exhibited that the approach of photothermal therapy nanomaterials boosting transformation of Fe 3+ into Fe 2+ in tumor cells can highly improve Fenton reaction for efficient chemodynamic therapy. This strategy was demonstrated to have an excellent antitumor activity both in vitro and in vivo, which provides an innovative perspective to Fenton reaction-based chemodynamic therapy.
Polyethylene (PE) is one of the most widely used materials in the world, but it is virtually undegradable and quickly accumulates in nature, which may contaminate the environment. We utilized the cobaltmediated radical copolymerization (CMRP) of ethylene and cyclic ketene acetals (CKAs) to effectively incorporate ester groups into PE backbone as cleavable structures to make PE-based copolymer degradable under mild conditions. The content of ethylene and ester units in the produced copolymer could be finely regulated by CKA concentration or ethylene pressure. Also, the copolymerization of ethylene and CKA with other functional vinyl monomers can produce functional and degradable PEbased copolymer. All the formed PE-based copolymers could degrade in the presence of trimethylamine (Et 3 N).
Marangoni-effect-driven actuators (MDAs) have the advantages of direct light-to-work conversion and convenient operation, which makes it widely researched in the cutting-edge fields including robots, micromachines, and intelligent systems. However, the MDA relies on the surface tension difference and it only works on the 2D liquid-air interface. Besides, the MDAs are normally pure black due to the light-absorption material limitation. Herein, a transparent light-driven 3D movable actuator (LTMA) and a 3D manipulation strategy are proposed. The LTMA is composed of photothermal nanoparticles-doped temperature-responsive hydrogel, whose surface energy changes as the nanoparticles absorb light energy. The 3D manipulation strategy combines Marangoni effect with photothermal buoyancy flow for realizing complex self-propellant and floating/sinking motions. The LTMA can perform more advanced tasks such as 3D obstacle avoidance and 3D sampling. Benefiting from the porous structure of hydrogel, LTMA can naturally absorb the chemical molecules for remote sampling and automated drug delivery. The light-driven, transparent, three-dimensionally movable, and programmable actuator has promising prospects in the field of micromachines and intelligent systems.
The rapid developments
of gene therapy are benefit from the construction
of efficient gene vectors, which help therapy genes efficiently overcome
the barriers in the transport and transfection. Condensing DNA into
nanoparticles is a crucial role in gene transfection, and the electrostatic
interactions of synthetic cationic liposomes and cationic polymers
with DNA are generally used for condensing DNA. Recent research has
shown that the introduction of the hydrophobic interaction, hydrogen
bonding, and coordinative interactions to the gene delivery vectors
is also very important for DNA condensation, delivery, and transfection.
This review focuses on the four types of interactions in condensed
DNA nanoparticles, which could provide a new perspective for improving
gene transfection efficacy.
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