A Novel and Low-Cost Disposable Device for Phototherapy of Neonatal Jaundice
Giovana R. Ferreira, Cláudia K. B. de Vasconcelos, Mariana M. Silva, Fabrício A. dos Santos, Jorge G.
Pires, André S. Duarte, Andrea G. C. Bianchi, Rodrigo. F. Bianchi
LAPPEM – DEFIS, Universidade Federal de Ouro Preto, 35400-000 Ouro Preto – MG, Brazil.
ABSTRACT
The present work details, to the best of our knowledge, the first examination of the influence of blue-
light radiation on the optical properties of organic luminescent films in attempting to develop an
indicating dosimeter for phototherapy of neonatal jaundice. Jaundice is one of the most common problems
encountered in newborns derived from immature functioning of the liver. The operating principle of the
device here presented is based on the optical response of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-
phenylene (MEH-PPV) and tris(8-hydroxyquinolinato) aluminum (Alq
3
) materials dispersed in
polystyrene (PS) matrix (denoted as PS/MEH-PPV/Alq
3
). It is observed a blue-shift on the
photoluminescence of PS/MEH-PPV/Alq
3
system from red to orange-yellow and then to green as function
of the blue-light radiation exposure time. The result is attributed to the spectral overlap between emission
of Alq
3
and absorption of MEH-PPV. The optical response of PS/MEH-PPV/Alq
3
to radiation was
investigated to design and develop a low-cost (< US$ 0.05) “smart” sensor to easily represent the radiation
dosage generally used in blue-light phototherapy. The basic idea behind this concept considers the sensor
as a traffic light device where red represents underdose and green the prescribed dose or overdose, while
orange-yellow suggests that radiation therapy is an ongoing process. This personal real-time radiation
dosimeter appears here as a key requirement for successful development of innovative tools in effective
management of the radiation dose planning where control of dose absorption by neonates is of extreme
importance.
INTRODUCTION
Neonatal jaundice is caused by hyperbilirubinemia and it is a common problem resulting from a liver
disease in the neonatal period [1]. Approximately 60% of normal newborns (40 million people) are
affected worldwide. The standard treatment for this health problem is phototherapy whose effectiveness
depends on the time newborns are exposed to light and the luminous intensity and spectrum irradiance of
light source [2]. The most effective spectrum of light for maximal effectiveness of phototherapy is
remarkably the blue LED [3, 4] (peaking near 455 nm [1], 40 W/cm
2
/nm [5]), which is also the most
attractive choice because its emission spectrum is similar to the bilirubin absorption spectrum [6]. Several
types of light source have been used in phototherapy units, many of them having output in the blue region
(420-450 nm) [7] and irradiance values different from those required to enhance the effectiveness of
treatment [8]. Despite this concern, more recent studies have shown either that no single standardized
method or instrument designed to detect and measure radiant energy are routinely used for reporting the
correct phototherapy dosages in the clinical literature [2]. It follows from the preceding observation that
there is a need for an effective management of blue-light radiation dose planning before treatment of
neonatal jaundice. This step is likely to reduce the under-exposure problems especially for those situations
caused by the extremely high serum bilirubin levels which may result in high risk of permanent brain
damage [9]. One notable advance in the development of the dosimeter for blue-light phototherapy was
recently shown by the authors [10,11,12] who used the low reliability of luminescent polymers to
demonstrate the potential use of an organic system as smart material for devices whose dose accumulation
Mater. Res. Soc. Symp. Proc. Vol. 1209 © 2010 Materials Research Society 1209-P03-03