Associate Member of the Staff
Director, Applied Molecular Photomedicine Laboratory
Clinical Research Collaborative
email:
University of Athens, Greece, D.D.S., 1984, Dentistry
University of Munich, Germany, Ph.D., 1989, Biology of Oral Cancer
University of London, UK, M.Sc., 1991, Experimental Oral Pathology
The Applied Molecular Photomedicine Laboratory (AMPL) was founded at The Forsyth Institute in 2002 by Dr. Nikos Soukos with the support of an award from the National Institutes of Dental and Craniofacial Research (NIDCR). AMPL is dedicated to exploring the full potential for the use of light in oral medicine and surgery. It is a multi-disciplinary translational research environment, in which scientists, clinicians and engineers have developed a productive and successful partnership. AMPL serves as a two-way transfer between basic science and patient care seeking to bridge the gap between them by developing hypotheses based on findings obtained from both basic and clinical research. AMPL aligns its research along two original scientific themes that put great emphasis on establishing principles for 1) prevention, control and/or treatment of oral infectious diseases (tooth decay, gum disease, dental pulp disease), and 2) detection and treatment of early oral cancer.
A few projects currently under way include the following:
We develop microbial biofilms evolved in vitro from saliva and subgingival plaque inocula. These biofilms are reproducible, analogous to that of natural dental plaque and provide a means for testing drug delivery and therapeutic procedures.
In confocal reflectance microscopy biofilms are illuminated by a laser source and backscattered (or reflected) light is collected by a detector. Image contrast is determined by natural differences in refractive indices of various structures within biofilms. Gray-scale images are displayed in real-time on a video monitor and represented horizontal (en face) optical sections through the biofilm.
We have proposed the use of visible (blue) light as a bactericidal agent in vivo to eliminate dental plaque pathogens by activating their endogenous porphyrins. The selective inhibition of the growth and metabolism of these species may lead to biofilm disruption and eventually to decreasing the pathogenic bacterial load. The result will be the prophylactic stabilization of the normal microbial composition of the plaque, even under conditions that may otherwise predispose a site to periodontitis.
Periodontitis is a destructive chronic inflammatory condition of the supporting structures of the teeth that arises as the result of the interaction of microorganisms and their products in dental plaque (periodontal biofilm) with host defense mechanisms. Our goal is to develop a photochemotherapeutic system for the treatment of periodontitis. A photoactive compound or "photosensitizer" could be introduced into the dental pocket followed by red light illumination via an optical fiber (photodynamic therapy or "PDT"). This technique would offer the following advantages in the hypothetical case of its in vivo application: (a) rapid application of the drug in the dental pocket and rapid bacterial killing after a short time of exposure of the dental pockets to light; (b) killing could easily be confined to the lesion by restricting irradiation to this region, so that microflora at other sites would remain intact; and (c) light would be delivered topically, rapidly and non-invasively. Our current work is focused on the photosensitization of periodontal biofilms in vitro using a series of different photosensitizers.
Endodontic failures are caused by the proliferation of residual bacteria that are left behind within the root canal due to the complexity of the root canal system that makes complete debridement with instrumentation and irrigation alone almost impossible. More than 2 million root canal retreatments due to residual microorganisms are performed yearly in the US. PDT may be an adjunctive procedure to kill residual root canal bacteria after their sensitization with a photoactive drug and their subsequent exposure to light. We envision the application of PDT in clinical practice as follows. The photoactive drug will be applied in the root canal system after instrumentation is complete for a short time (up to 5 minutes) and will strongly bind to the negatively charged matrix and to bacteria. Then a fiber optic will be used to deliver red light from a diode laser to irradiate microbial biofilms on the root canal surface as well as in the dentinal tubules. The entire root canal system will be exposed to light simultaneously for 5 minutes.
Photomechanical waves (PW) generated by ablation with high power lasers are fast rise time compressional waves whose effects are caused by mechanical forces. Recently, we have shown that PW enhance the permeability of microbial biofilms. The combination of PW delivery and PDT has been shown to disrupt resistant biofilms. We have proposed that the synergistic action of PW and PDT can be used as a powerful treatment tool for control of infections. Some of the potential applications to infectious diseases are: dental caries, periodontitis, cystic fibrosis pneumonia, native valve endocarditis, as well as infections of contacts lenses, urinary catheters, endotracheal tubes, vascular grafts, mechanical heart valves, and orthopedic devices.
The "NanoPhotomedicine Initiative" is a major research effort that introduces a new direction to Oral Research. Nanoparticles belong to a new class of multifunctional biophotonic systems that will not only serve as high-quality diagnostic fluorescent agents for noninvasive tumor detection, but also as noninvasive malignant and bacterial destruction systems with light-activated properties. The initiative initiates the development of a unique research program based on multidisciplinary collaborative research efforts among clinicians, scientists, and engineers.
Fimple JL, Fontana CR, Foschi F, Ruggiero K, Song X, Pagonis TC, Tanner AC, Kent R, Doukas AG, Stashenko PP, Soukos NS. (2008) Photodynamic treatment of endodontic polymicrobial infection in vitro. J. Endod. 34(6):728-34.
Soukos NS, Chen PS-Y, Morris JT, Ruggiero K, Abernethy AD, Som S, Foschi F, Doucette S, Luschke Bammann L, Raquel Fontana C, Doukas AG, Stashenko PP. (2006) Photodynamic therapy for endodontic disinfection. J Endod (in print).
Soukos NS, Som S, Abernethy A, Ruggiero K, Dunham J, Lee C, Doukas AG, Goodson JM. (2005) Phototargeting oral black-pigmented bacteria. Antimicrob. Agents Chemother. 49 (4): 1391-1396.
Soukos NS, Mulholland SE, Socransky SS, Doukas AG. (2003) Photodestruction of human dental plaque bacteria. Enhancement of the photodynamic effect by photomechanical waves in an oral biofilm model. Lasers Surg. Med. 33: 161-168.
Soukos NS, Hamblin MR, Keel S, Fabian R, Hasan T (2001) Epidermal growth factor receptor as a target for immunophotodiagnosis and photoimmunotherapy of oral precancer. Cancer Res. 61: 4490-4496.
Doukas AG, Soukos NS, Ball S, Appa Y, Kollias N (2001) Fluorescence excitation spectroscopy for the measurement of epidermal proliferation. Photochem. Photobiol. 74 (1): 96-102.
Soukos NS, Socransky S, Mulholland SE, Lee S, Doukas AG (2000) Photomechanical drug delivery into bacterial biofilms. Pharmaceutical Res. 17 (4): 405-409.
Soukos NS, Crowley K, Bamberg MP, Gillies R, Doukas AG, Evans R, Kollias N (2000) A rapid method to detect dried saliva stains swabbed from human skin using fluorescence spectroscopy. Forensic Sci. Int. 3: 133-138.
Soukos NS, Himenez-Fyvie LA, Hamblin MR, Socransky SS, Hasan T (1998) Targeted antimicrobial photochemotherapy. Antimicrobial Agents Chemother. 42 (10): 2595-2601.
Karriann Ruggiero, BS
Reza Riahi, D.M.D.
Tony Vera, D.M.D.
Federico Foschi, D.D.S., Ph.D.
Carla Fontana, D.D.S., Ph.D.
Ryan Blisset, B.S.
