# Northwestern Polytechnical University: albumin nanoparticles raise radical yield 20.3-fold in mouse tumor tests

- Published: 2026-11-06 03:17 UTC
- Section: Life & Health › Medicine
- Tags: mitochondria-targeted photosensitizer, type-I photodynamic therapy, pyrido cyanines, McL3@HSA, human serum albumin nanoparticles, superoxide generation, intersystem crossing, hypoxic tumors, Northwestern Polytechnical University, nude mice tumor model
- URL: https://realtech.media/news/rt-a969b171b61d4263461f5d1e_northwestern_polytechnical_university/

**A mitochondria-targeted photosensitizer in albumin nanoparticles produced 20.3 times more superoxide than its base analogue and suppressed tumor growth under hypoxia in nude mice, authors report.**

![Northwestern Polytechnical University: albumin nanoparticles raise radical yield 20.3-fold in mouse tumor tests](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/d76a555273537a2d.jpg)
*Unknown photographer, Wikimedia Commons, Public domain*

A team led by Prof. Lin Li at the School of Flexible Electronics, Northwestern Polytechnical University (China), developed a photosensitizer for mitochondria-targeted photodynamic therapy that keeps working at low oxygen levels. The work was published in Research; experiments were done in cells and in a subcutaneous transplantation model in nude mice [1].

## Molecular design: three donor/π-bridge branches

Photodynamic therapy uses photosensitizers that produce reactive oxygen species under light. Conventional type-II photosensitizers rely on oxygen to make singlet oxygen, which limits their action in hypoxic tumors. Type-I photosensitizers generate superoxide (•O2−) and hydroxyl (•OH) radicals through electron transfer and depend less on oxygen.

The authors built a series of cationic pyrido cyanines with a (D-π)n-A architecture (n = 1, 2, 3), named McL1, McL2 and McL3. More donor/π-bridge branches strengthened intramolecular charge transfer. McL3 showed broader visible-light absorption and a smaller singlet–triplet energy gap (ΔES1-T3 = 0.24 eV). Its •O2− production was 4.2 times that of McL1 [1].

## Albumin confinement: second boost

McL3 was then self-assembled with human serum albumin (HSA) into McL3@HSA nanoparticles with an average size of about 40 nm. Confinement in the HSA binding pocket narrowed ΔES1-T2 to 0.08 eV and raised •O2− generation to 20.3 times that of McL1 [1].

Mechanistic studies indicate that HSA confinement modulates molecular conformation and increases intersystem crossing efficiency from 33% to 52%, which enables efficient type-I radical generation [1].

## Cell and mouse results

In cells and in nude mice, McL3@HSA accumulated selectively in mitochondria. Under white-light irradiation it produced •O2− and •OH and caused structural damage to mitochondria. According to the authors, apoptosis and tumor growth inhibition were maintained under hypoxic conditions [1].

The results were obtained in cell cultures and in mice; clinical data are not reported. The authors describe the combination of multi-branched molecular design and albumin confinement as a route to mitochondria-targeted, hypoxia-tolerant photosensitizers [1].

## Sources

1. [Research](https://doi.org/10.34133/research.1279)
2. [EurekAlert](https://www.eurekalert.org/news-releases/1150563)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-a969b171b61d4263461f5d1e_northwestern_polytechnical_university/