Table 3.

A summary of the representative materials, strengths, and shortcomings of different oxygen delivery approaches for hypoxic tumor PDT. ¹O₂, singlet oxygen. ZIF-90, zeolitic imidazolate framework-90.

Strategy	Representative Materials	Strengths	Shortcomings
Hemoglobin	Modified hemoglobin, red blood cells	Tumor-specific oxygen release owing to Bohr effect, ability of the red blood cell membrane to escape from immune clearance	Low oxygen loading capacity, safety concern
Perfluorocarbon	Perfluorohexane, perfluorooctyl bromide, perfluoro-15-crown-5-ether, perfluorotributylamine	High oxygen loading capacity, FDA-approved materials such as perfluorohexane, increased 1O2 lifetime	Relatively weak tumor-specific oxygen release
Metal–organic frameworks	UiO-66, ZIF-90	Multifunctionality, high oxygen loading capacity	Potential toxicity arisen from metal ions