Naphthalene Endoperoxide Heterodimer Designed for Sustained Singlet Oxygen Release

Laser-activatable oxygen self-supplying nanoplatform for efficiently overcoming colorectal cancer resistance by enhanced ferroptosis and alleviated hypoxic microenvironment

BACKGROUND

Colorectal cancer (CRC) is the second most deadly cancer worldwide, with chemo-resistance remaining a major obstacle in CRC treatment. Notably, the imbalance of redox homeostasis-mediated ferroptosis and the modulation of hypoxic tumor microenvironment are regarded as new entry points for overcoming the chemo-resistance of CRC.

METHODS

Inspired by this, we rationally designed a light-activatable oxygen self-supplying chemo-photothermal nanoplatform by co-assembling cisplatin (CDDP) and linoleic acid (LA)-tailored IR820 via enhanced ferroptosis against colorectal cancer chemo-resistance. In this nanoplatform, CDDP can produce hydrogen peroxide in CRC cells through a series of enzymatic reactions and subsequently release oxygen under laser-triggered photothermal to alleviate hypoxia. Additionally, the introduced LA can add exogenous unsaturated fatty acids into CRC cells, triggering ferroptosis via oxidative stress-related peroxidized lipid accumulation. Meanwhile, photothermal can efficiently boost the rate of enzymatic response and local blood flow, hence increasing the oxygen supply and oxidizing LA for enhanced ferroptosis.

RESULTS

This nanoplatform exhibited excellent anti-tumor efficacy in chemo-resistant cell lines and showed potent inhibitory capability in nude mice xenograft models.

CONCLUSIONS

Taken together, this nanoplatform provides a promising paradigm via enhanced ferroptosis and alleviated hypoxia tumor microenvironment against CRC chemo-resistance.

Oxygen-Generating Biomaterials for Translational Bone Regenerative Engineering

Successful regeneration of critical-size defects remains one of the significant challenges in regenerative engineering. These large-scale bone defects are difficult to regenerate and are often reconstructed with matrices that do not provide adequate oxygen levels to stem cells involved in the regeneration process. Hypoxia-induced necrosis predominantly occurs in the center of large matrices since the host tissue's local vasculature fails to provide sufficient nutrients and oxygen. Indeed, utilizing oxygen-generating materials can overcome the central hypoxic region, induce tissue in-growth, and increase the quality of life for patients with extensive tissue damage. This article reviews recent advances in oxygen-generating biomaterials for translational bone regenerative engineering. We discussed different oxygen-releasing and delivery methods, fabrication methods for oxygen-releasing matrices, biology, oxygen's role in bone regeneration, and emerging new oxygen delivery methods that could potentially be used for bone regenerative engineering.

Aromatic Endoperoxides

The fundamental aspects of aromatic endoperoxide chemistry are reviewed including their synthesis and reactions. The discussion will focus on factors that will both enhance and prevent the formation of aromatic endoperoxides, and on structural features that will provide control over their ability to release singlet oxygen. This approach recognizes the dual use of aromatic hydrocarbons as both precursors of endoperoxides and as valuable materials for incorporation in electronic and photonic devices. Improvement of the existing methods and development of new methods for the synthesis of endoperoxides is necessary as result of the demand to improve existing and to create new applications for these valuable materials. On the other hand, prevention of endoperoxide formation is crucial to inhibit irreversible oxidative degradation of aromatic hydrocarbons and to extend their lifetimes as useful organic semiconductors.