# TARGETED PHOTODYNAMIC ACTION

> **NIH NIH R01** · BOWLING GREEN STATE UNIVERSITY · 1988 · $84,987

## Abstract

"Photoradiation therapy is therapy requiring the use of a photosensitizer
to elicit a therapeutic effect when the sensitizer is activated by photons
in the visible region of the spectrum."  Its recent use was pioneered by
Dougherty who reported that fluorescein derivatives could be activated by
488 nm light to reduce the growth rate of mammary in mice1 and that
hematoporphyrin derivative could be activated with red light to cause
complete eradication of mammary tumors in mice and rats.

Rose bengal is a xanthene dye whose properties have been studied in detail
by Neckers.  It is a useful sensitizer for singlet oxygen formation in many
different solvents and molecular forms, including polymeric ones.  Its
structure can be modified easily and structural changes cause little change
in photochemical or photophysical characteristics.  It is a purpose of this
proposal to further develop the chemistry of this dye, which like most
dyes, is very complicated.  We intend to make it the prototypical dye
system on which future dye modifications and chemistries for
phototherapeutic applications can be based.

It is our intention to demonstrate that by proper structural modification
this sensitizer can be directed to specific oxidizable substrates to
increase the selectivity of oxidation of a specific partner molecule, and
use this targeted photosensitizer concept to alter the rate of, and
products obtained from, these oxidation processes.  We call this the
principle of targeted photodynamic action.  Rose bengal, 4, will be
functionalized to react with enzymes and antibodies and these will be used
to attract selectively other molecular entities such as substrates,
inhibitors, or antigens.  This should attract these latter entities to the
site of the sensitizer functionalized enzyme, or antibody, and hence to the
source of singlet oxygen.  It should enhance the local concentration of the
potential singlet oxygen acceptor in the vicinity of the source - the
sensitizer.  We intend to apply this principle, Targeted Photodynamic
Action, in tumor phototherapy.  Collaborations are arranged with 1.
Dougherty (photodynamic therapy), C. W. Lin (bladder cancer phototherapy),
and J. Spikes (xanthene dye incorporation into liposomes), and A. Oseroff
(functionalized monoclonal antibodies).

## Key facts

- **NIH application ID:** 3179081
- **Project number:** 5R01CA039715-03
- **Recipient organization:** BOWLING GREEN STATE UNIVERSITY
- **SAM.gov UEI:** SLT3EB6G3FA9
- **Principal Investigator:** DOUGLAS C NECKERS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $84,987
- **Award type:** 5
- **Project period:** 1986-04-01 → 1990-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3179081

## Citation

> US National Institutes of Health, RePORTER application 3179081, TARGETED PHOTODYNAMIC ACTION (5R01CA039715-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3179081. Licensed CC0.

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