# Erythrocyte-derived particles for near infrared phototherapy of port wine stains.

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA RIVERSIDE · 2022 · $534,208

## Abstract

Port wine stain (PWS) is a congenital and progressive malformations of the dermal capillaries. 
Pulsed dye laser (POL) irradiation in the visible wavelength range of 585-600 nm remains 
 as the gold standard of treatment. The underlying treatment principle is based on the 
absorption of POL light by hemoglobin to induce irreversible photothermal coagulation of the 
vasculature. However, therapeutic efficacy with POLs remains limited due to insufficient 
penetration of light in skin, and non-specific absorption by the epidermal melanin pigments. 
Clinically acceptable outcomes are achieved in only about 20% of patients with diminishing returns 
beyond five treatment sessions. Our long-term objective is the development of a new therapeutic 
approach based on intravascular administration of optical micro-particles, fabricated from 
erythrocytes, as targets for pulsed near infrared (NIR) laser treatment at 755 nm. These 
micro-particles are doped with indocyanine green (ICG), the only FOA-approved NIR chromophore. The 
underlying premise is based on reduced absorption of light by melanin, strong ICG absorption, 
and availability of dermatological lasers at 755 nm. A particularly innovative feature of 
these micro-particles is that their membrane is enriched with cholesterol to prevent the flipping 
of phosphatidylserine from the inner to the outer leaflet of the membrane, which would 
 otherwise serve as a signal for removal of the particles from the vasculature. We refer to these 
micro-particles as c⁺- µNETs. By using c⁺-µNETs, we aim to prolong the circulation time of ICG, and 
increase its availability in the lesion vasculature so that more sites can be treated 
during a given session, ultimately leading to minimal therapeutic sessions to clear the 
stain. Another innovative aspect is the use of transgenic mice whose melanin content can be 
varied in a controllable manner to simulate the epidermal response of PWS with 
different pigmentations to 755 nm laser irradiation. We will use these mice to determine the 
threshold values of the laser radiant exposures for epidermal injury and blood vessels 
photocoagulation in conjunction with c⁺-µNETs. We will also use a rabbit model to 
characterize the circulation and biodistribution dynamics of c⁺-µNETs, determine the 
therapeutic window of time when using c⁺-µNETs, and evaluate the vascular response as it relates 
to laser irradiation parameters and dose of c⁺-µNETs. SA 1: Fabricate and characterize c⁺-µNETs. SA 
2: Characterize the circulation and biodistribution dynamics of c⁺-µNETs. SA 3: Evaluate 
 the therapeutic efficacy of c⁺-µNETs in conjunction with pulsed NIR laser irradiation. A key 
outcome of our proposed studies is that we will know the maximum length of time over which 
effective blood vessels photocoagulation can be achieved when using c⁺-µNETs, in addition to 
finding the appropriate radiant exposure levels for vascular photocoagulation in skins 
with various pigmentations. This knowl...

## Key facts

- **NIH application ID:** 10367141
- **Project number:** 2R01AR068067-05A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA RIVERSIDE
- **Principal Investigator:** BAHMAN ANVARI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $534,208
- **Award type:** 2
- **Project period:** 2016-03-10 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10367141

## Citation

> US National Institutes of Health, RePORTER application 10367141, Erythrocyte-derived particles for near infrared phototherapy of port wine stains. (2R01AR068067-05A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10367141. Licensed CC0.

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