Direct and Indirect Chemiluminescence: Reactions, Mechanisms and Challenges.

Marina A Tzani,Michael G Kallitsakis,Natasa P Kalogiouri,Panagiotis A Angaridis,Michael A Terzidis,Ioannis N Lykakis,Dimitra K Gioftsidou,Nikolaos V Pliatsios

doi:10.3390/molecules26247664

Abstract

Emission of light by matter can occur through a variety of mechanisms. When it results from an electronically excited state of a species produced by a chemical reaction, it is called chemiluminescence (CL). The phenomenon can take place both in natural and artificial chemical systems and it has been utilized in a variety of applications. In this review, we aim to revisit some of the latest CL applications based on direct and indirect production modes. The characteristics of the chemical reactions and the underpinning CL mechanisms are thoroughly discussed in view of studies from the very recent bibliography. Different methodologies aiming at higher CL efficiencies are summarized and presented in detail, including CL type and scaffolds used in each study. The CL role in the development of efficient therapeutic platforms is also discussed in relation to the Reactive Oxygen Species (ROS) and singlet oxygen (1O2) produced, as final products. Moreover, recent research results from our team are included regarding the behavior of commonly used photosensitizers upon chemical activation under CL conditions. The CL prospects in imaging, biomimetic organic and radical chemistry, and therapeutics are critically presented in respect to the persisting challenges and limitations of the existing strategies to date.

Highlights

Chemiluminescence (CL) is the spontaneous emission of light from an electronically excited state of a species produced by a chemical reaction [1]
Bioluminescence occurs from in situ enzyme-catalyzed chemical transformations, for example luciferin [4] reacts with oxygen in the presence of luciferase enzyme [5], magnesium [6,7,8,9] or calcium ions and adenosine triphosphate (ATP), leading to luminescence [10,11,12]
The aim of this review is to provide a summary of the recent developments in this fiaahnseaaladslyc,bhtbiEeceamasleleenisdecextgnocrsnieotiatndcitveihiorirteenyacmtptisearionidlndducuelmiucnltdediiecnsidrteaercalsostlococCenhdLgnee.swcmAcerintiihb(coEeradveClecilrenLyvnir,)teeiiwiln.asedtoi.tio,fhcnaatethntioevpeetsrhtleoreexadcaatemtpugrppiocelltinescisaol.tetnirTaoadhnoinenafsrgnolfdilteegofrouhbrfrette1thOtbaeecy2rr tiaonneaxt deelevecltorpomdeent(Fofigmuorreee3ffi)c.iNenut CmL-einroduucsedrethveireawpeuatrictipcllaetfsoramnsd

Summary

Introduction

Chemiluminescence (CL) is the spontaneous emission of light from an electronically excited state of a species produced by a chemical reaction [1]. The reaction involves chemical activation of specific molecules (A) via oxidation, resulting in a chemiexcited intermediate (CEI) (C* or D*; excited species indicated by *) that releases its energy either via light emission (direct) or by transferring it, through a chemiluminescence resonance energy transfer (CRET) process, to an adjacent fluorophore (E) that becomes excited (E*); this fluorophore subsequently releases part of its energy by emitting light.

Indirect Chemiluminescence

Future Prospects