Type Of Photosensitizer Research Articles

[2+2] and [2+1] Cycloaddition of myrcene for synthesis of highly strained bio-fuels with high density and high impulse

Developing bio-fuels provides a sustainable strategy to reduce the dependence on finite fossil fuels. But biomass-based fuel molecules usually lack strained structure, resulting in undesirable density and impulse for aerospace applications. Herein, the highly strained bio-fuels are synthesized from myrcene by photoinduced [2+2] cycloaddition and hydrogenation/cyclopropanation reactions. The triplet energy transfer mechanism is revealed through theoretical calculations, triplet quenching experiments and phosphorescent measurement. The reaction conditions of photocycloaddition reaction are optimized, including the photosensitizer type and amount, solvent effect, substrate concentration, reaction temperature and light intensity. Under the optimal conditions, the yield of target photocycloaddition products reaches ca. 82.61%, which are then hydrogenated and cyclopropanized to two kinds of bio-fuels, namely PC@HG and PC@CP, respectively, which have high density of 0.836 and 0.886 g·mL-1, high impulse of 326.71 and 329.42 s, superior cryogenic properties, and good combustion properties. This work provides a feasible pathway for the preparation of highly strained bio-fuels with high density and high impulse.

Combined use of 5-ALA-induced protoporphyrin IX and chlorin e6 for fluorescence diagnostics and photodynamic therapy of skin tumors.

Different types of photosensitizers (PSs) have different dynamics and intensities of accumulation, depending on the type of tumor or different areas within the same tumor. This determines the effectiveness of fluorescence diagnostics and photodynamic therapy (PDT). This paper studies the processes of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) and chlorin e6 (Ce6) accumulation in the central and border zones of a tumor after combined administration of two PSs into the patient's body. Fluorescence diagnostic methods have shown that sublingual administration of 5-ALA leads to the more intense accumulation of PpIX in a tumor compared to oral administration. Differences have been identified in the dynamics of 5-ALA-induced PpIX and Ce6 accumulation in the central and border zones of the tumor, as well as normal tissues. Ce6 accumulates mainly in the central zone of the tumor while PpIX accumulates in the border zone of the tumor. All patients with combined PDT experienced complete therapeutic pathomorphosis and relapse-free observation.

Tratamento endodôntico associado a terapia fotodinâmica em dente anterior: relato de caso

Photodynamic therapy acts on biostimulation at the cellular level, thus accelerating tissue repair and promoting analgesia. Often with conventional treatment it is not possible to achieve success and it is necessary to use alternative therapies, photodynamic therapy is used as one of these alternative therapies, demonstrating which types of photosensitizers and light can be used and how it is possible to help combat the infection. bacterial. Photosensitizers have the function of absorbing red light in the region and producing singlet oxygen. Therefore, the objective of this work was to perform endodontic treatment on element 21 with a periapical lesion, with the aid of photodynamic therapy associated with the photosensitizer Methylene Blue.

Application of Peptide-Conjugated Photosensitizers for Photodynamic Cancer Therapy: A Review

Photodynamic therapy (PDT) is a clinically approved therapeutic option for the treatment of various types of cancer. PDT calls for the application of photosensitizers (PSs) and photoactivation with a particular light wavelength while tissue oxygen is present. Anticancer efficacy depends on the combination of these three substrates leading to the generation of cytotoxic reactive oxygen species (ROS) that promote apoptosis, necrosis, and autophagy of cancer cells. However, one of the biggest problems with conventional PDT is the poor accumulation and targeting of PSs to tumor tissues, resulting in undesirable side effects and unfavorable therapeutic outcomes. To overcome this, new photosensitizers have been developed through bioconjugation and encapsulation with targeting molecules, such as peptides, allowing a better accumulation and targeting in tumor cells. Several studies have been conducted to test the efficacy of several peptide-conjugated photosensitizers and improve PDT efficacy. This review aims to present current insights into various types of peptide-conjugated photosensitizers, with the goal of enhancing cancer treatment efficacy, addressing the limitations of conventional PDT, and expanding potential applications in medicine.

Polystyrene microplastics enhanced the photo-degradation and -ammonification of algae-derived dissolved organic matters

Algae-derived organic matter (ADOM) is a key source of chromophoric dissolved organic matter (CDOM) in natural waters. When exposed to solar irradiation, ADOM undergoes gradual degradation and transformation. The escalating presence of microplastics (MPs) can act as a novel type of environmental photosensitizer, however its impacts on ADOM photodegradation remains largely unexplored. Thus, in this study, ADOM were extracted from four common algal species (Microcystis aeruginosa, Synechococcus sp., Chlorella pyrenoidosa and Scenedesmus obliquus) and exposed to UV irradiation with or without polystyrene (PS) MPs, namely ADOM+PS groups and ADOM groups, respectively. The results indicated that a more rapid degradation of amino acid-like substances (∼38 % vs. ∼22 %) and more ammonia products (1.86 vs. 1.21 mg L−1) were observed in the ADOM+PS groups compared to the ADOM groups after a five-day exposure. This enhanced photodegradation might be attributed to the production of environmentally persistent free radicals and reactive species during the photoaging of PS. Furthermore, PS-derived high electron transfer belt activity of ADOM led to the production of highly aromatic and humified products. These humic-like products could potentially accelerate the degradation of amino acid-like compounds by exciting the generation of excited triplet CDOM. This study underscores the role of MPs as environmental photosensitizers in promoting ADOM degradation and ammonia generation, providing insights on the transformation of ADOM mediated by emerging pollutants and its impact on aquatic carbon and nitrogen cycles.

Reversible pH-switchable NIR-II nano-photosensitizer for precise imaging and photodynamic therapy of tumors

Photodynamic therapy (PDT) has attracted widespread attention from researchers as an emerging cancer treatment method. There have been many reports on various types of NIR-II photosensitizers for imaging and treatment of tumor sites. However, there are few reports on the development of NIR-II organic small molecule photosensitizers that have intelligent response to the tumor microenvironment, precise imaging, real-time treatment, and high biocompatibility. In this work, we developed a series of NIR-II photosensitizers (RBTs) with near-infrared excitation, good photostability, and large Stokes shift. Among them, RBT-Br exhibited higher reactive oxygen species (ROS) generation efficiency due to the introduction of halogen heavy atoms to enhance intersystem crossing (ISC). It is noteworthy that RBT-Br can generate singlet oxygen (1O2) and superoxide anion radicals (•O2−) simultaneously under 730 nm laser. Subsequently, we used molecular engineering technology to construct three pH-responsive NIR-II photosensitizers (RBT-pHs) by utilizing the closure of the lactam ring, among which RBT-pH-1 (pKa = 6.78) is able to be directionally activated under the stimulation of tumor micro-acid environment, with its fluorescence emission window reaching 933 nm. Subsequently, RBT-pH-1 NPs encapsulated in DSPE-mPEG5k were applied for PDT treatment of mouse tumors. The results showed that RBT-pH-1 NPs were activated by the acidic tumor microenvironment and generated ROS under laser excitation, exhibiting precise tumor imaging and significant tumor growth inhibition. We look forward to these multifunctional NIR-II organic small molecule photosensitizers providing a more efficient approach for clinical treatment of tumors. Statement of significanceA reversible pH-switchable NIR-II nano-photosensitizer RBT-pH-1 NPs (pKa = 6.76) is developed for precise imaging and PDT therapy of mouse tumors, which can be effectively used for targeted enrichment and activation of tumor micro-acid environments. The results show that this NIR-II photosensitizer generates ROS through tumor micro-acid environment stimulation and laser triggering, showing precise tumor imaging guidance and significant tumor growth inhibition.

Photodynamic therapy in management of cutaneous leishmaniasis: A systematic review.

This systematic review evaluated the efficacy and safety of photodynamic therapy (PDT) in the management of cutaneous leishmaniasis (CL). The electronic search for identification of relevant studies, adhered to the PICOS (Population, Intervention, Comparator, Outcomes and Study type) framework, was conducted through PubMed, Google scholar, Dimensions, X-mol, and Semantic Scholar till December 2023. All types of studies reporting PDT in the management of CL with no language restriction were included. Methodological quality appraised of the selected studies was performed using Jadad index. Of the 317 identified studies, 21 reported PDT for the treatment of CL lesions, consisting of two randomized controlled trials (RCTs), four single-center open study, one case series and 14 case reports. Collectively, these studies presented a total of 304 patients with ages ranging from 1 to 82years, undergoing varying number of PDT sessions (3-28) and follow-up durations spanning 4weeks to 24months. The CL lesions predominantly manifested on the exposed body areas, such as face, limbs, neck, ear and nose, and characterized with the use of clinical variables, such as plaques, papules, erythema and ulceration. PDT protocols differed in the photosensitizer type, incubation time, light source characteristics (e.g., wavelength, output power, and energy density), duration of light illumination, number of PDT sessions and their respective frequencies. Treatment response was assessed through the clinical presentation (i.e., at the baseline and after PDT completion) or by the absence of Leishmania parasites. Adverse effects comprised of pain, burning and tingling sensation experienced during PDT, followed by erythema, pigmentation changes and edema post-treatment. This systematic review revealed that PDT is an efficacious and safe modality for the treatment of CL, with mild and transient side effects.

Emerging A-D-A fused-ring photosensitizers for tumor phototheranostics.

As we all know, cancer is still a disease that we are struggling against. Although the traditional treatment options are still the mainstream in clinical practice, emerging phototheranostics technologies based on photoacoustic or fluorescence imaging-guided phototherapy also provide a new exploration direction for non-invasive, low-risk and highly efficient cancer treatment. Photosensitizers are the core materials to accomplish this mission. Recently, more attention has been paid to the emerging A-D-A fused-ring photosensitizers. A-D-A fused-ring photosensitizers display strong and wide absorption spectra, high photostability and easy molecular modification. Since this type of photosensitizer was first used for tumor therapy in 2019, its application boundaries are constantly expanding. Therefore, in this feature article, from the perspective of molecular design, we focused on the development of these molecules for application in phototheranostics over the past five years. The effects of tiny structural changes on their photophysical properties are discussed in detail, which provides a way for structural optimization of the subsequent A-D-A photosensitizers.

Understanding the essentials of photodynamic therapy for dental practitioners: Shining a spotlight

Background: Oral disorders, including tooth decay, periodontal disease, and endodontic infections, are prevalent worldwide. The escalating issue of antibiotic resistance exacerbates the need for alternative treatment modalities. Aim: This review aims to provide a comprehensive overview of advancements in photodynamic therapy (PDT) for dental applications, highlighting its potential as a non-invasive local and adjuvant therapy for various oral infectious disorders. PDT, which originated in the early 20th century, involves three primary components: A photosensitizer (PS), light, and oxygen. The PS selectively targets unwanted eukaryotic cells, such as tumors in the oral cavity, or pathogenic microorganisms, while sparing healthy cells. The efficacy of PDT is significantly influenced by the type of PS utilized. Method: An electronic search was conducted using the PubMed database focusing on peer-reviewed articles up to November 2023 using the keywords “photodynamic therapy,” “photochemotherapy,” “antimicrobial photodynamic therapy,” “antimicrobial photodynamic therapy oral,” resulting in 2341, 1034, 389, 221, and 96 items, respectively. After appropriate review, relevant data from other electronic sources are also included for additional information. Results: Historical and recent studies have demonstrated the effectiveness of porphyrin PSs and temoporfin in treating premalignant and malignant intraoral lesions, particularly as palliative treatments when conventional therapies have failed. In addition, phenothiazinium PSs, such as methylene blue and toluidine blue, have shown substantial antimicrobial activity against bacteria, viruses, and fungi. PDT has been applied successfully to treat specific oral conditions, including caries, endodontic and mucosal infections, periodontal disorders, and periimplantitis. Notably, its antibacterial properties suggest that PDT could reduce the dependency on systemic antibiotics. Conclusion: PDT emerges as a promising alternative to conventional treatments for oral infections, offering a potential solution to the global challenge of antibiotic resistance. Continued research and development are essential to enhance the effectiveness and broaden the application of PDT in dental care.

Chromophore-Assisted Light Inactivation for Protein Degradation and Its Application in Biomedicine.

The functional investigation of proteins holds immense significance in unraveling physiological and pathological mechanisms of organisms as well as advancing the development of novel pharmaceuticals in biomedicine. However, the study of cellular protein function using conventional genetic manipulation methods may yield unpredictable outcomes and erroneous conclusions. Therefore, precise modulation of protein activity within cells holds immense significance in the realm of biomedical research. Chromophore-assisted light inactivation (CALI) is a technique that labels photosensitizers onto target proteins and induces the production of reactive oxygen species through light control to achieve precise inactivation of target proteins. Based on the type and characteristics of photosensitizers, different excitation light sources and labeling methods are selected. For instance, KillerRed forms a fusion protein with the target protein through genetic engineering for labeling and inactivates the target protein via light activation. CALI is presently predominantly employed in diverse biomedical domains encompassing investigations into protein functionality and interaction, intercellular signal transduction research, as well as cancer exploration and therapy. With the continuous advancement of CALI technology, it is anticipated to emerge as a formidable instrument in the realm of life sciences, yielding more captivating outcomes for fundamental life sciences and precise disease diagnosis and treatment.

Mechanism research of type I reactive oxygen species conversion based on molecular and aggregate levels for tumor photodynamic therapy

AbstractType I photosensitizers (PSs) with the ability to generate reactive oxygen species (ROS) containing superoxide anion and hydroxyl radical have promising application potential for treating hypoxia tumors, but the deep mechanism of type II ROS converts to the type I ROS in the PSs is still unclear, it is urgent to reveal influencing factors about inducing type I ROS generation. Herein, six PSs with aggregation‐induced emission properties, which were fabricated with the same electronic acceptor but different electronic donors and “π‐bridge”, have been successfully prepared to explore the influencing mechanism of generating superoxide anion and hydroxyl radical from organic PSs. Experimental results discovered two factors containing molecular structure and aggregated environment could decide the ROS efficiency and types of PSs. On the level of designing molecular structure, we discovered that “π‐bridge” with a lower energy level of the lowest triplet state could be beneficial for triggering the production of superoxide anion, and electronic donor of triphenylamine was an important factor in producing hydroxyl radical than another donor of dimethylamine. On the level of designing aggregates of PS‐based polymeric nanoparticles, bovine serum albumin could improve largely the generation efficiency of superoxide anion. Due to the satisfactory ROS efficiency and better biocompatibility, synthetic PSs showed excellent photodynamic therapy outcomes in vitro/vivo.

Visible Light-Driven Hydrogen Evolution Catalysis by Heteroleptic Ni(II) Complexes with Chelating Nitrogen Ligands: Probing Ligand Substituent Position and Photosensitizer Effects

This study aims to advance the field of green chemistry and catalysis by exploring alternatives to conventional non-renewable energy sources. Emphasis is placed on hydrogen as a potential fuel, with a focus on the catalytic properties of Ni(II) complexes when coordinated with o-phenylenediamine and diimine ligands. We report the synthesis and comprehensive characterization, with various physical and spectroscopic techniques, of three heteroleptic Ni(II) complexes: [Ni(1,10-phenanthroline)(o-phenylene diamine)] (1), [Ni(2,2-dimethyl-2,2-bipyridine)(o-phenylene diamine)] (2), and [Ni(5,5-dimethyl-2,2-bipyridine)(o-phenylene diamine)] (3). The catalytic activity of these complexes for hydrogen evolution was assessed through photochemical studies utilizing visible light irradiation. Two distinct photosensitizers, fluorescein and quantum dots, were examined under diverse conditions. Additionally, their electrocatalytic behavior was investigated to elucidate the hydrogen evolution reaction (HER) mechanism, revealing a combined proton-coupled electron transfer (PCET)/electron-coupled proton transfer (ECPT) mechanism attributed to the chemical nature of the diamine ligand. The influence of ligand substituent position, ligand chemical nature, and photosensitizer type on catalytic performance was systematically studied. Among the complexes investigated, complex 2 demonstrated superior catalytic performance, achieving a turnover number (TON) of 3357 in photochemical experiments using fluorescein as a photosensitizer. Conversely, complex 1 exhibited the highest TON of 30,066 for HER when quantum dots were employed as the photosensitizer.

Engineered protein cages with enhanced extracellular drug release for elevated antitumor efficacy

Human heavy chain ferritin (HFn) protein cage has been explored as a nanocarrier for targeted anticancer drug delivery. Here, we introduced a matrix metalloproteinases (MMPs)-cleavable sequence into the DE loop of HFn, creating an MMP-responsive variant, MR-HFn, for localized and extracellular drug release. The crystal structure of MR-HFn revealed that the addition of the MMPs recognition sequence did not affect the self-assembly of HFn but presented a surface-exposed loop susceptible to MMPs cleavage. Biochemical analysis indicated that this engineered protein cage is responsive to MMPs, enabling the targeted release of encapsulated drugs. To evaluate the therapeutic potential of this engineered protein cage, monosubstituted β-carboxy phthalocyanine zinc (CPZ), a type of photosensitizer, was loaded inside this protein cage. The prepared CPZ@MR-HFn showed higher uptake and stronger phototoxicity in MMPs overexpressed tumor cells, as well as enhanced penetration into multicellular tumor spheroids compared with its counterpart CPZ@HFn in vitro. In vivo, CPZ@MR-HFn displayed a higher tumor inhibitory rate than CPZ@HFn under illumination. These results indicated that MR-HFn is a promising nanocarrier for anticancer drug delivery and the MMP-responsive strategy here can also be adapted for other stimuli.

Bacterial-mediated FRET between AIE and ACQ photosensitizers for enhanced antimicrobial photodynamic therapy

Antimicrobial photodynamic therapy (aPDT) effectively treats multidrug-resistant bacterial infections by utilizing photosensitizers to generate cytotoxic reactive oxygen species. Exploiting fluorescence resonance energy transfer (FRET) effect shows great potential for enhancing the efficacy of aPDT. Typically, this method involves encapsulating fluorescent molecules, including photosensitizers, into nanomaterials or coadsorbing them onto materials. Here, we develop a strategy that directly utilizes bacteria as carriers to bring two types of photosensitizers together to induce the FRET. We designed an aggregation-induced emission (AIE) photosensitizer (CPVBP3) and an aggregation-caused quenching (ACQ) photosensitizer (TPP3), both featuring the same bacterial membrane-targeting group to direct them to bacteria. Under white light exposure (12 J/cm2), the bactericidal effect of the combination of CPVBP3 and TPP3 at 5 µM each on Escherichia coli (4.7 log10) was much stronger than their individual use at 5 or 10 µM, highlighting synergistic antibacterial action. In Escherichia coli, TPP3 absorbed the fluorescence of CPVBP3, reducing its lifetime from 0.98 ns to 0.74 ns, confirming the occurrence of FRET. This combination also demonstrated a significantly stronger synergistic aPDT effect on Acinetobacter baumannii. Moreover, CPVBP3 synergized with methylene blue against Escherichia coli, indicating the universality of this strategy. Additionally, the efficacy and biosafety of this therapeutic approach were validated in a mouse wound model infected with Escherichia coli. In summary, this FRET strategy overcomes the limitations associated with the need for pre-binding photosensitizers with materials and the challenge of these mixtures penetrating bacteria (for greater damage), ultimately opening new avenues for further enhancing the efficacy of aPDT.

Near-infrared Light-Induced Polymerizations: Mechanisms and Applications.

Photopolymerizations have garnered significant attention in polymer science due to their low polymerization temperature, high production efficiency, environmental friendliness, and spatial controllability. Despite these merits, the poor penetration and severe chemical damage from ultraviolet/visible (UV/Vis) light resources pose significant barriers to their success in conventional photopolymerizations. A recent breakthrough involving the utilization of near-infrared (NIR) laser with long wavelength has been exploited for diverse applications. With the combination of a NIR photosensitizer (PS), NIR-induced photopolymerizations have been successfully developed to alleviate the challenges in conventional methods. The enhancement of penetration depth and safety of NIR-induced photopolymerizations can contribute significantly to improving the efficiency of polymerization for production of intricate structures across various scales. In this concept, the typical types of PSs and polymerization mechanisms (PMs) within the NIR-induced photopolymerization systems have been classified in detail. Additionally, the applications of various polymers achieved by NIR-induced photopolymerizations are summarized. Furthermore, research directions and future challenges of this field are also discussed comprehensively.

Applications of Antimicrobial Photodynamic Therapy in Aquaculture: Effect on Fish Pathogenic Bacteria

Increased infectious diseases and the reduced effectiveness of antibiotics due to antimicrobial resistance pose global challenges affecting the aquaculture industry. As bacteria increasingly develop antibiotic resistance, research scientists are shifting their focus to technologies such as antimicrobial photodynamic therapy (aPDT), which show potential for treating and controlling fish infections without promoting the development of resistant bacteria. Various photosensitizers (PSs), both natural and synthetic, are under investigation for their application in aPDT within the aquaculture industry. This shift is crucial for the sustainability of the aquaculture industry, which plays a significant role in achieving several of the United Nations (UN) Sustainable Development Goals (SDGs). This review highlights the application of aPDT against fish pathogens in the industry and the types of PSs utilized. It also explores the potential application of this technique for treating and controlling fish infections, along with the advantages and limitations of its use in aquaculture production systems. Finally, a conclusion and future perspectives are provided.

Influence of Photosensitizer on Photodynamic Therapy for Peri-Implantitis: A Systematic Review.

The treatment of peri-implantitis is challenging in the clinical practice of implant dentistry. With limited therapeutic options and drug resistance, there is a need for alternative methods, such as photodynamic therapy (PDT), which is a minimally invasive procedure used to treat peri-implantitis. This study evaluated whether the type of photosensitizer used influences the results of inflammatory control, reduction in peri-implant pocket depth, bleeding during probing, and reduction in bone loss in the dental implant region. We registered the study in the PROSPERO (International Prospective Register of Systematic Review) database. We searched three main databases and gray literature in English without date restrictions. In vivo randomized clinical studies involving individuals with peri-implantitis, smokers, patients with diabetes, and healthy controls were included. PDT was used as the primary intervention. Comparators considered mechanical debridement with a reduction in pocket depth as the primary outcome and clinical attachment level, bleeding on probing, gingival index, plaque index, and microbiological analysis as secondary outcomes. After reviewing the eligibility criteria, we included seven articles out of 266. A great variety of photosensitizers were observed, and it was concluded that the selection of the most appropriate type of photosensitizer must consider the patient's characteristics and peri-implantitis conditions. The effectiveness of PDT, its effects on the oral microbiome, and the clinical patterns of peri-implantitis may vary depending on the photosensitizer chosen, which is a crucial factor in personalizing peri-implantitis treatment.

A protocol for an overview of systematic reviews to map photodynamic inactivation evidence in different dental specialties.

This is a protocol for an overview to summarize the findings of Systematic Reviews (SR) dealing with Photodynamic Inactivation (PDI) for control of oral diseases. Specific variables of oral infectious will be considered as outcomes, according to dental specialty. Cochrane Database of Systematic Reviews (CDSR), MEDLINE, LILACS, Embase, and Epistemonikos will be searched, as well as reference lists. A search strategy was developed for each database using only terms related to the intervention (PDI) aiming to maximize sensitivity. After checking for duplicate entries, selection of reviews will be performed in a two-stage technique: two authors will independently screening titles and abstracts, and then full texts will be assessed for inclusion/exclusion criteria. Any disagreement will be resolved through discussion and/or consultation with a third reviewer. Data will be extracted following the recommendations in Chapter V of Cochrane Handbook and using an electronic pre-specified form. The evaluation of the methodological quality and risk of bias (RoB) of the SR included will be carried out using the AMSTAR 2 and ROBIS. Narrative summaries of relevant results from the individual SR will be carried out and displayed in tables and figures. A specific summary will focus on PDI parameters and study designs, such as the type and concentration of photosensitizer, pre-irradiation time, irradiation dosimetry, and infection or microbiological models, to identify the PDI protocols with clinical potential. We will summarize the quantitative results of the SRs narratively.

Antimicrobial therapy using VIS plus water-filtered infrared-A as an alternative method to treat oral diseases.

Oral biofilm is the main cause of pathologies affecting the hard and soft oral tissues around teeth. Its main components are the periodontal pathogens and other bacteria of the supragingival and subgingival biofilm. Different alternative strategies that could be adjuvants to the usual periodontal treatments used to eliminate biofilms are available. One of these methods is antimicrobial photodynamic therapy using VIS and water-filtered infrared-A combined with a photosensitizer. In this review, different recent studies were collected to evaluate the antimicrobial effects of antimicrobial photodynamic therapy and the effectiveness of different types of photosensitizers.

Free base porphyrin-cyanine dye conjugate: synthesis and optical properties.

The covalent combination of a cyanine dye (IR-783) with a tetraphenyl porphyrin unit through an ether linkage results in a photoactive system capable of producing singlet oxygen. The synthesis, characterization and photophysical properties of the resulting novel free base porphyrin-cyanine conjugate named TPPO-IR-783 (TOI) is reported. Excited state properties were studied in various solvents with differing polarity. The fluorescence is strongly solvent dependent, however this is not the case for singlet oxygen phosphorescence, which is only observed in tetrahydrofuran (THF), when comparing 8 different polar, non-polar and medium-polarity solvents. This novel type of porphyrin-cyanine photosensitizer has the ability to produce singlet oxygen and absorbs light at NIR wavelengths.