PhD Defence by Aikaterini Argyraki

Title:  New light Sources for Biomedical Applications

Principal supervisor: Professor Paul Michael Petersen
Co-supervisor: Carsten Dam-Hansen

Evaluation Board:
Chairman, Group leader Christian Pedersen, DTU Fotonik
Dr. Janis Spigulis, Institute of Atomic Physics and Spectroscopy / Physics Department, University of Latvia,
MD. Klaus Per Juul Martiny, Head of the Intensive outpatient unit for affective disorders, Psychiatric Center Copenhagen, Rigshospitalet

Master of the Ceremony
Senior Researcher Ole Bjarlin Jensen, DTU Fotonik

This PhD thesis explores the potential health benefits that can be imposed by light interventions performed with ultraviolet (UV) light emitting diodes (LEDs) or visible (VIS) LED lighting systems.
Based on a cross-disciplinary approach the scope of this PhD project was 1) to investigate, by a systematic approach, effects imposed by narrowband UV irradiation, on systems with biological relevance and 2) to generate statistically significant evidence that VIS LED lighting systems, can improve several dimensions of human health and human performance.

Bacterial communities forming biofilms and their inactivation by narrowband UV irradiation in the range 250-340 nm, was investigated. Radiant exposure at 20.000 J/m2 with central wavelength at 296nm was proven adequate to totally inactivate immature biofilms. This treatment was shown to be more effective than 1) photodynamic therapy, 2) conventional antibiotics, and 3) equally effective to combinatory antibiotics. However, effective inactivation (99.9%) on mature biofilms was only achieved after a novel treatment was invented, namely “light assisted antibiotics”.

Additionally, significant vitamin D enrichment of various food products (pig skin, salmon skin and eggs) was achieved.

Application of specially designed LED illuminations resulted in 1) better vein identification 2) better sleep for elderly women 3) and lowered the risk for C-section, as well as, enabled elite athletes to conserve their sleep patterns under jetlag conditions.


tor 07 dec 17
13:00 - 16:00


DTU Fotonik


Lyngby Campus
Building 306, auditorium 33