title: Advances and challenges in label-free nonlinear optical imaging using two-photon excitation fluorescence and second harmonic generation for cancer research.
abstract: Nonlinear optical imaging (NLOI) has emerged to be a promising tool for bio-medical imaging in recent times. Among the various applications of NLOI, its utility is the most significant in the field of pre-clinical and clinical cancer research. This review begins by briefly covering the core principles involved in NLOI, such as two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG). Subsequently, there is a short description on the various cellular components that contribute to endogenous optical fluorescence. Later on the review deals with its main theme--the challenges faced during label-free NLO imaging in translational cancer research. While this review addresses the accomplishment of various label-free NLOI based studies in cancer diagnostics, it also touches upon the limitations of the mentioned studies. In addition, areas in cancer research that need to be further investigated by label-free NLOI are discussed in a latter segment. The review eventually concludes on the note that label-free NLOI has and will continue to contribute richly in translational cancer research, to eventually provide a very reliable, yet minimally invasive cancer diagnostic tool for the patient.
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands; Centre for Optical Diagnostics and Therapy, Erasmus Medical Centre, Post Box 2040, 3000 CA, Rotterdam, the Netherlands. Electronic address: gijuthomas82@gmail.com.
authors.forename: Giju
authors.initials: G
authors.lastname: Thomas
authors.affiliation: Department of Molecular Biophysics, Utrecht University, 3508 TA Utrecht, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: van Voskuilen
authors.affiliation: Department of Molecular Biophysics, Utrecht University, 3508 TA Utrecht, The Netherlands.
authors.forename: Hans C
authors.initials: HC
authors.lastname: Gerritsen
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
authors.forename: H J C M
authors.initials: HJ
authors.lastname: Sterenborg
mesh_terms: D000818:Animals; D006801:Humans; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000473:pathology*; D061848:Optical Imaging; D017785:Photons
keywords: Cancer diagnostics; Endogenous optical fluorescence; Label-free; Nonlinear optical imaging; Second harmonic generation; Two-photon excitation fluorescence