Native fluorescence, or autofluorescence (AF), consists in the emission of light in the UV-visible, near-IR spectral range when biological substrates are excited with light at suitable wavelength. This is a well-known phenomenon, and the strict relationship of many endogenous fluorophores with morphofunctional properties of the living systems, influencing their AF emission features, offers an extremely powerful resource for directly monitoring the biological substrate condition. Starting from the last century, the technological progresses in microscopy and spectrofluorometry were convoying attention of the scientific community to this phenomenon. In the future, the interest in the autofluorescence will certainly continue. Current instrumentation and analytical procedures will likely be overcome by the unceasing progress in new devices for AF detection and data interpretation, while a progress is expected in the search and characterization of endogenous fluorophores and their roles as intrinsic biomarkers.

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Autofluorescence spectroscopy and imaging: a tool for biomedical research and diagnosis.

Targeted and effective photodynamic therapy for cancer using functionalized nanomaterials.

A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major step forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors. It also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.

http://pubs.acs.org/doi/pdf/10.1021/nn505051d

Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

Aminolevulinic acid (ALA) is an endogenous metabolite normally formed in the mitochondria from succinyl-CoA and glycine. Conjugation of eight ALA molecules yields protoporphyrin IX (PpIX) and finally leads to formation of heme. Conversion of PpIX to its downstream substrates requires the activity of a rate-limiting enzyme ferrochelatase. When ALA is administered externally the abundantly produced PpIX cannot be quickly converted to its final product - heme by ferrochelatase and therefore accumulates within cells. Since PpIX is a potent photosensitizer this metabolic pathway can be exploited in photodynamic therapy (PDT). This is an already approved therapeutic strategy making ALA one of the most successful prodrugs used in cancer treatment.

https://www.mdpi.com/1420-3049/16/5/4140/pdf

Aminolevulinic Acid (ALA) as a Prodrug in Photodynamic Therapy of Cancer

Background European guidelines for the management of basal cell carcinoma (BCC) prepared by the former BCC subcommittee of the Guidelines Committee of the European Dermatology Forum (EDF) were published in 2006. ObjectivesTo present updated guidelines that include consensual expert definitions on various BCC types, prognosis and risk factors for BCC as well as review recommendations for diagnosis and treatment reflecting current published evidence. MethodsThese guidelines (S1 type) were prepared by the new BCC subgroup of the European Dermatology Forum (EDF)’s Guidelines Committee through extensive literature review (up to 2012) and expert experience; they were extensively discussed within the EDF subcommittee and approved by peer reviewers of the EDF.ResultsBCC is a common tumour with an incidence rising worldwide. Three major clinical types of BCC are recognized: nodular, superficial and morpheaform. Four histological subtypes are defined: superficial, nodular, infiltrative and morpheaform. On the basis of the risk of relapse, three prognosis groups have been identified: high, intermediate and low risk. According to these classifications and evidence-based evaluation of the therapeutic strategies available, a decision tree is proposed for the management of BCCs. Conclusions. The guidelines offer a useful tool that will help dermatologists to select the most appropriate treatment for individual patients.

Kai Chen

Papers

Role of the c-Jun N-terminal kinase signaling pathway in SW480 cell apoptosis in response to 5-aminolevulinic acid-based photodynamic therapy