Light Technology for Efficient and Effective Photodynamic Therapy: A Critical Review

Design of a new porphyrin-based compound and investigation of its photosensitive properties for antibacterial photodynamic therapy

Considering the increasing number of pathogens resistant to commonly used antibiotics as well as antiseptics, there is an urgent need for antimicrobial approaches that can effectively inactivate pathogens without the risk of establishing resistance. An alternative approach in this context is antibacterial photodynamic therapy (APDT). APDT is a process that involves bacterial cell death using appropriate wavelength light energy and photosensitizer and causes the production of reactive oxygen species inside or outside the microbial cell depending on the penetration of light energy. In our study, a new porphyrin compound 4,4'-methylenebis(2-((E)-((4-(10,15,20-triphenylporphyrin-5-yl)phenyl)imino)methyl)phenol) (SP) was designed and synthesized as photosensitizer and its structure was clarified by NMR (13C and 1H) and mass determination method. Photophysical and photochemical properties were examined in detail using different methods. Singlet oxygen quantum yields were obtained as 0.48 and 0.59 by direct and indirect methods, respectively. Antibacterial activity studies have been conducted within the scope of biological activity and promising results have been obtained under LED light (500-700 nm, 265 V, 1500 LM), contributing to the antibacterial photodynamic therapy literature.

Visible and Red Light-Triggered Anticancer Profile of a Ferrocene-Re(I)-Tricarbonyl Conjugate: Experimental and Theoretical Studies

We have red-shifted the light absorbance property of a Re(I)-tricarbonyl complex via distant conjugation of a ferrocene moiety and developed a novel complex ReFctp, [Re(Fctp)(CO)3Cl], where Fctp = 4'-ferrocenyl-2,2':6',2″-terpyridine. ReFctp showed green to red light absorption ability and blue emission, indicating its potential for photodynamic therapy (PDT) application. The conjugation of ferrocene introduced ferrocene-based transitions, which lie at a higher wavelength within the PDT therapeutic window. The time-dependent density functional theory and excited state calculations revealed an efficient intersystem crossing for ReFctp, which is helpful for PDT. ReFctp elicited both PDT type I and type II pathways for reactive oxygen species (ROS) generation and facilitated NADH (1,4-dihydro-nicotinamide adenine dinucleotide) oxidation upon exposure to visible light. Importantly, ReFctp showed effective penetration through the layers of clinically relevant 3D multicellular tumor spheroids and localized primarily in mitochondria (Pearson's correlation coefficient, PCC = 0.65) of A549 cancer cells. ReFctp produced more than 20 times higher phototoxicity (IC50 ∼1.5 μM) by inducing ROS generation and altering mitochondrial membrane potential in A549 cancer cells than the nonferrocene analogue Retp, [Re(CO)3(tp)Cl], where tp = 2,2':6',2″-terpyridine. ReFctp induced apoptotic mode of cell death with a notable photocytotoxicity index (PI, PI = IC50dark/IC50light) and selectivity index (SI, SI = normal cell's IC50dark/cancer cell's IC50light) in the range of 25-33.

Assays on 3D tumor spheroids for exploring the light dosimetry of photodynamic effects under different gaseous conditions

The multifaceted nature of photodynamic therapy (PDT) requires a throughout evaluation of a multitude of parameters when devising preclinical protocols. In this study, we constructed MCF-7 human breast tumor spheroid assays to infer PDT irradiation doses at four gradient levels for violet light at 408 nm and red light at 625 nm under normal and hypoxic oxygen conditions. The compacted three-dimensional (3D) tumor models conferred PDT resistance as compared to monolayer cultures due to heterogenous distribution of photosensitizers along with the presence of internal hypoxic region. Cell viability results indicated that the violet light was more efficient to kill cells in the spheroids under normal oxygen conditions, while cells exposed to the hypoxic microenvironment exhibited minimal PDT-induced death. The combination of 3D tumor spheroid assays and the multiparametric screening platform presented a solid framework for assessing PDT efficacy across a wide range of different physiological conditions and therapeutic regimes.

Miniature wireless LED-device for photodynamic-induced cell pyroptosis

The inability of visible light to penetrate far through biological tissue limits its use for phototherapy and photodiagnosis of deep-tissue sites of disease. This is unfortunate because many visible dyes are excellent photosensitizers and photocatalysts that can induce a wide range of photochemical processes, including photogeneration of reactive oxygen species. One potential solution is to bring the light source closer to the site of disease by using a miniature implantable LED. With this goal in mind, we fabricated a wireless LED-based device (volume of 23 mm3) that is powered by RF energy and emits light with a wavelength of 573 nm. It has the capacity to excite the green absorbing dye Rose Bengal, which is an efficient type II photosensitizer. The wireless transfer of RF power is effective even when the device is buried in chicken breast and located 6 cm from the transmitting antenna. The combination of a wireless device as light source and Rose Bengal as photosensitizer was found to induce cell death of cultured HT-29 human colorectal adenocarcinoma cells. Time-dependent generation of protruding bubbles was observed in the photoactivated cells suggesting cell death by light-induced pyroptosis and supporting evidence was gained by cell staining with the fluorescence probes Annexin-V FITC and Propidium Iodide. The results reveal a future path towards a wireless implanted LED-based device that can trigger photodynamic immunogenic cell death in deep-seated cancerous tissue.

Low-cost, 3D printed irradiation system for in vitro photodynamic therapy experiments

The development of a suitable irradiation setup is essential for in vitro experiments in photodynamic therapy (PDT). While various irradiation systems have been developed for PDT, only a few offer practical and high-quality setups for precise and reproducible results in cell culture experiments. This report introduces a cost-effective illumination setup designed for in vitro photodynamic treatments. The setup consists of a commercially available light-emitting diode (LED) lamp, a cooling unit, and a specially designed 3D-printed enclosure to accommodate a multiwell plate insert. The LED lamp is versatile, supporting various irradiation wavelengths and adjustable illumination fields, ensuring consistent and reliable performance. The study evaluates the setup through various parameters, including photon flux density, illumination uniformity, photon distribution across the multiwell plate, and temperature changes during irradiation. In addition, the effectiveness of the LED-based illumination system is tested by treating mouse mammary breast carcinoma cells (4T1) with Rose Bengal and LED irradiation at around 525 nm. The resulting IC50 of 5.2 ± 0.9 μM and a minimum media temperature change of ca. 1.2°C indicate a highly promising LED-based setup that offers a cost-effective and technically feasible solution for achieving consistent, reproducible, and uniform irradiation, enhancing research capabilities and potential applications.

Light-Activatable Photocaged UNC2025 for Triggering TAM Kinase Inhibition in Bladder Cancer

Photopharmacology is an emerging field that utilizes photo-responsive molecules to enable control over the activity of a drug using light. The aim is to limit the therapeutic action of a drug at the level of diseased tissues and organs. Considering the well-known implications of protein kinases in cancer and the therapeutic issues associated with protein kinase inhibitors, the photopharmacology is seen as an innovative and alternative solution with great potential in oncology. In this context, we developed the first photocaged TAM kinase inhibitors based on UNC2025, a first-in-class small molecule kinase inhibitor. These prodrugs showed good stability in biologically relevant buffer and rapid photorelease of the photoremovable protecting group upon UV-light irradiation (<10 min.). These light-activatable prodrugs led to a 16-fold decrease to a complete loss of kinase inhibition, depending on the protein and the position at which the coumarin-type phototrigger was introduced. The most promising candidate was the N,O-dicaged compound, showing the superiority of having two photolabile protecting groups on UNC2025 for being entirely inactive on TAM kinases. Under UV-light irradiation, the N,O-dicaged compound recovered its inhibitory potency in enzymatic assays and displayed excellent antiproliferative activity in RT112 cell lines.

BODIPY precursors and their cyclotriphosphazene Derivatives: Synthesis, photochemical properties and their application in PDT

Photodynamic therapy (PDT) is a treatment method consisting of common combination of oxygen, light energy and a light absorbing molecule called a photosensitizer. In this work, four new compounds consisting of BODIPY precursors and BODIPY-cyclotriphosphazene derivatives were synthesized to investigate the PDT effects. The chemical structures of the compounds were characterized and then their photophysical properties were determined by spectroscopic techniques. The precursor BODIPYs and their cyclotriphosphazene derivatives exhibited similar properties such as strong absorption intensity, high photostability and low fluorescence profile in the NIR region. Additionally, the singlet oxygen production capacities of these compounds were determined using the photobleaching technique of 1,3-diphenylisobenzofuran (DPBF) under light illumination. By introducing iodine atoms into the molecule, which are responsible for the intersystem transition (ISC) enhancement, a more efficient singlet oxygen production was achieved in both the iodinated-BODIPY and its cyclotriphosphazene derivative. Anticancer activities of the precursor BODIPYs and their cyclotriphosphazene derivatives in the absence and presence of light illumination were evaluated on cancerous cell lines (PC3 and DU145) and non-tumorigenic prostate epithelial PNT1a cell. The compounds triggered the death of cancer cell PC3 the more significantly in the presence of red light compared to the healthy cells (PNT1a).

Light Control in Microbial Systems

Light is a key environmental component influencing many biological processes, particularly in prokaryotes such as archaea and bacteria. Light control techniques have revolutionized precise manipulation at molecular and cellular levels in recent years. Bacteria, with adaptability and genetic tractability, are promising candidates for light control studies. This review investigates the mechanisms underlying light activation in bacteria and discusses recent advancements focusing on light control methods and techniques for controlling bacteria. We delve into the mechanisms by which bacteria sense and transduce light signals, including engineered photoreceptors and light-sensitive actuators, and various strategies employed to modulate gene expression, protein function, and bacterial motility. Furthermore, we highlight recent developments in light-integrated methods of controlling microbial responses, such as upconversion nanoparticles and optical tweezers, which can enhance the spatial and temporal control of bacteria and open new horizons for biomedical applications.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.

A Bioorthogonal Antidote Against the Photosensitivity after Photodynamic Therapy

As an effective and non-invasive treatment modality for cancer, photodynamic therapy (PDT) has attracted considerable interest. With the recent advances in the photosensitizing agents, the fiber-optic systems, and other aspects, its application is extended to a wide range of superficial and localized cancers. However, for the few clinically used photosensitizers, most of them suffer from the drawback of causing prolonged photosensitivity after the treatment. As a result, post-PDT management is also a crucial issue. Herein, a facile bioorthogonal approach is reported that can effectively suppress this common side effect of PDT in nude mice. It involves the use of an antidote that contains a black-hole quencher BHQ-3 conjugated with a bicyclo[6.1.0]non-4-yne (BCN) moiety and a tetrazine-substituted boron dipyrromethene-based photosensitizer. By using tumor-bearing nude mice as an animal model, it is demonstrated that after PDT with this photosensitizer, the administration of the antidote can effectively quench the photodynamic activity of the residual photosensitizer by bringing the BHQ-3 quencher close to the photosensitizing unit through a rapid click reaction. It results in substantial reduction in skin damage upon light irradiation. The overall results demonstrate that this simple and facile strategy can provide an effective means for minimizing the photosensitivity after PDT.

Photodynamic treatment of malignant melanoma with structured light: in silico Monte Carlo modeling

In this report, we propose a novel strategy for the photodynamic approach to the treatment of melanoma, aiming to mitigate the excessive absorption and consequent thermal effects. The cornerstone of this approach is an innovative structured illumination technique that optimizes light delivery to the tissue. The methodology of this in silico study involves the development of an optical model of human skin with the presence of melanoma and an accurate simulation technique of photon transport within the complex turbid scattering medium. To assess the effectiveness of our proposed strategy, we introduced a cost function reflecting the irradiated volume and optical radiation absorption within the target area/volume occupied by malformation. By utilizing the cost function, we refine the offset illumination parameters for a variety of target system parameters, ensuring increased efficiency of photodynamic therapy. Our computer simulation results introduce a promising new path towards improved photodynamic melanoma treatments, potentially leading to better therapeutic outcomes and reduced side effects. Further experimental validation is needed to confirm these theoretical advancements, which could contribute towards revolutionizing current melanoma photodynamic treatment methodologies.

Clinical Practice of Photodynamic Therapy for Non-Small Cell Lung Cancer in Different Scenarios: Who Is the Better Candidate?

BACKGROUND

Photodynamic therapy (PDT) is a relatively safe and highly selectivity antitumor treatment, which might be increasingly used as a supplement to conventional therapies. A clinical overview and detailed comparison of how to select patients and lesions for PDT in different scenarios are urgently needed to provide a basis for clinical treatment.

SUMMARY

This review demonstrates the highlights and obstacles of applying PDT for lung cancer and underlines points worth considering when planning to initiate PDT. The aim was to make out the appropriate selection and help PDT develop efficacy and precision through a better understanding of its clinical use.

KEY MESSAGES

Increasing evidence supports the feasibility and safety of PDT in the treatment of non-small cell lung cancer. It is important to recognize the factors that influence the efficacy of PDT to develop individualized management strategies and implement well-designed procedures. These important issues should be worth considering in the present and further research.

Photodynamic Therapy for Eye, Ear, Laryngeal Area, and Nasal and Oral Cavity Diseases: A Review

Photodynamic therapy (PDT) has emerged as a promising modality for the treatment of various diseases. This non-invasive approach utilizes photosensitizing agents and light to selectively target and destroy abnormal cells, providing a valuable alternative to traditional treatments. Research studies have explored the application of PDT in different areas of the head. Research is focusing on a growing number of new developments and treatments for cancer. One of these methods is PDT. Photodynamic therapy is now a revolutionary, progressive method of cancer therapy. A very important feature of PDT is that cells cannot become immune to singlet oxygen. With this therapy, patients can avoid lengthy and costly surgeries. PDT therapy is referred to as a safe and highly selective therapy. These studies collectively highlight the potential of PDT as a valuable therapeutic option in treating the head area. As research in this field progresses, PDT may become increasingly integrated into the clinical management of these conditions, offering a balance between effectiveness and minimal invasiveness.

Review of three-dimensional spheroid culture models of gynecological cancers for photodynamic therapy research

Photodynamic therapy (PDT) is a specific cancer treatment with minimal side effects. However, it remains challenging to apply PDT clinically, partially due to the difficulty of translating research findings to clinical settings as the conventional 2D cell models used for in vitro research are accepted as less physiologically relevant to a solid tumour. 3D spheroids offer a better model for testing PDT mechanisms and efficacy, particularly on photosensitizer uptake, cellular and subcellular distribution and interaction with cellular oxygen consumption. 3D spheroids are usually generated by scaffold-free and scaffold-based methods and are accepted as physiologically relevant models for PDT anticancer research. Scaffold-free methods offer researchers advantages including high efficiency, reproducible, and controlled microenvironment. While the scaffold-based methods offer an extracellular matrix-like 3D scaffold with the necessary architecture and chemical mediators to support the spheroid formation, the natural scaffold used may limit its usage because of low reproducibility due to patch-to-patch variation. Many studies show that the 3D spheroids do offer advantages to gynceologcial cancer PDT investigation. This article will provide a review of the applications of 3D spheroid culture models for the PDT research of gynaecological cancers.

Hydrogel design to overcome thermal resistance and ROS detoxification in photothermal and photodynamic therapy of cancer

Responsive heat resistance (by heat shock protein upregulation) and spontaneous reactive oxygen species (ROS) detoxification have been regarded as the major obstacles for photothermal/photodynamic therapy of cancer. To overcome the thermal resistance and improve ROS susceptibility in breast cancer therapy, Au ion-crosslinked hydrogels including indocyanine green (ICG) and polyphenol are devised. Au ion has been introduced for gel crosslinking (by catechol-Au3+ coordination), cellular glutathione depletion, and O2 production from cellular H2O2. ICG can generate singlet oxygen from O2 (for photodynamic therapy) and induce hyperthermia (for photothermal therapy) under the near-infrared laser exposure. (-)-Epigallocatechin gallate downregulates heat shock protein to overcome heat resistance during hyperthermia and exerts multiple anticancer functions in spite of its ironical antioxidant features. Those molecules are concinnously engaged in the hydrogel structure to offer fast gel transformation, syringe injection, self-restoration, and rheological tuning for augmented photo/chemotherapy of cancer. Intratumoral injection of multifunctional hydrogel efficiently suppressed the growth of primary breast cancer and completely eliminated the residual tumor mass. Proposed hydrogel system can be applied to tumor size reduction prior to surgery of breast cancer and the complete remission after its surgery.

Aluminium phthalocyanine-mediated photodynamic therapy induces ATM-related DNA damage response and apoptosis in human oesophageal cancer cells

Introduction

Photodynamic therapy (PDT) is a light-based technique used in the treatment of malignant and non-malignant tissue. Aluminium-phthalocyanine chloride tetra sulfonate (AlPcS4Cl)-mediated PDT has been well investigated on several cancer types, including oesophageal cancer. However, the effects of (AlPcS4Cl)-mediated PDT on DNA damage response and the mechanism of cell death in oesophageal cancer needs further investigation.

Methods

Here, we examined the in vitro effects of AlPcS4Cl-mediated PDT on cell cycle, DNA damage response, oxidative stress, and intrinsic apoptotic cell death pathway in HKESC-1 oesophageal cancer cells. The HKESC-1 cells were exposed to PDT using a semiconductor laser diode (673.2 nm, 5 J/cm2 fluency). Cell viability and cytotoxicity were determined by the ATP cell viability assay and the lactate dehydrogenase (LDH) release assay, respectively. Cell cycle and DNA damage response (DDR) analyses were conducted using the Muse™ cell cycle kit and the Muse® multi-color DNA damage kit, respectively. The mode of cell death was identified using the Annexin V-FITC/PI detection assay and Muse® Autophagy LC3 antibody-based kit. The intrinsic apoptotic pathway was investigated by measuring the cellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm) function, cytochrome c levels and the activity of caspase 3/7 enzymes.

Results

The results show that AlPcS4Cl-based PDT reduced cell viability, induced cytotoxicity, cell cycle arrest at the G0/G1 phase, and DNA double-strand break (DSB) through the upregulation of the ataxia telangiectasia mutated (ATM), a DNA damage sensor. In addition, the findings showed that AlPcS4Cl-based PDT induced cell death via apoptosis, which is observed through increased ROS production, reduced ΔΨm, increased cytochrome c release, and activation of caspase 3/7 enzyme. Finally, no autophagy was observed in the AlPcS4Cl-mediated PDT-treated cells.

Conclusion

Our findings showed that apoptotic cell death is the main cell death mechanism triggered by AlPcS4Cl-mediated PDT in oesophageal cancer cells.

Stimuli-responsive hydrogel based on natural polymers for breast cancer

Aims: Breast cancer is the most common malignancy among women in both high- and low-resource settings. Conventional breast cancer therapies were inefficient and had low patient compliance. Stimuli-responsive hydrogels possessing similar physicochemical features as soft tissue facilitate diagnostic and therapeutic approaches for breast cancer subtypes. Scope: Polysaccharides and polypeptides are major natural polymers with unique biocompatibility, biodegradability, and feasible modification approaches utilized frequently for hydrogel fabrication. Alternating the natural polymer-based hydrogel properties in response to external stimuli such as pH, temperature, light, ultrasonic, enzyme, glucose, magnetic, redox, and electric have provided great potential for the evolution of novel drug delivery systems (DDSs) and various advanced technologies in medical applications. Stimuli-responsive hydrogels are triggered by specific cancer tissue features, promote target delivery techniques, and modify release therapeutic agents at localized sites. This narrative review presented innovation in preparing and characterizing the most common stimuli-responsive natural polymer-based hydrogels for diagnostic and therapeutic applications in the breast cancer area. Conclusion: Stimuli-responsive hydrogels display bioinspiration products as DDSs for breast cancer subtypes, protect the shape of breast tissue, provide modified drug release, enhance therapeutic efficacy, and minimize chemotherapy agents' side effects. The potential benefits of smart natural polymer-based hydrogels make them an exciting area of practice for breast cancer diagnosis and treatment.

Optimizing the average distance between a blue light photosensitizer and a harmonic nanoparticle for effective infrared photodynamic therapy

Photodynamic therapy can be significantly improved by techniques utilizing light windows of higher tissue penetration depths with optimally matched photoactive agents to provide deep interstitial treatment. Classical blue light photosensitizers were photodynamically activated using infrared light via coupled harmonic nanoparticles with optimized intermediary distances using spacers. Upon 800 nm pulsed laser irradiation perovskite nanoparticles with optimized coupling to either curcumin or protoporphyrin IX reduced the viability of MCF7 breast cancer cells by 73 percent and 64 percent, respectively, while exhibiting negligible dark toxicity. The findings pave the way for clinical adaptation of ease-of-synthesis photodynamically active preparations operable under deep tissue penetrating infrared lights using commonly available otherwise infrared inactive classical blue light photosensitizers.

Recent Advances in the HPPH-Based Third-Generation Photodynamic Agents in Biomedical Applications

Photodynamic therapy has emerged as a recognized anti-tumor treatment involving three fundamental elements: photosensitizers, light, and reactive oxygen species. Enhancing the effectiveness of photosensitizers remains the primary avenue for improving the biological therapeutic outcomes of PDT. Through three generations of development, HPPH is a 2-(1-hexyloxyethyl)-2-devinyl derivative of pyropheophorbide-α, representing a second-generation photosensitizer already undergoing clinical trials for various tumors. The evolution toward third-generation photosensitizers based on HPPH involves structural modifications for multimodal applications and the combination of multifunctional compounds, leading to improved imaging localization and superior anti-tumor effects. While research into third-generation HPPH is beneficial for advancing PDT treatment, equal attention should also be directed toward the other two essential elements and personalized diagnosis and treatment methodologies.

Physico-mechanical and antimicrobial properties of an elastomeric ligature coated with reduced nanographene oxide-nano curcumin subjected to dual-modal photodynamic and photothermal inactivation against Streptococcus mutans biofilms

BACKGROUND

White spot lesions (WSLs) are a common side effect of fixed orthodontic treatment. Streptococcus mutans is the primary causative agent of WSLs and dental caries on the teeth during treatment. According to the unique features of reduced graphene oxide-nano curcumin (rGO-nCur), this study aimed to investigate the mechanical properties and antimicrobial potency of rGO-nCur coated orthodontic elastomeric ligatures as a novel coating composite following dual-modal photodynamic inactivation (PDI) and photothermal inactivation (PTI) against S. mutans biofilms.

METHODS

After confirmation of rGO-nCur synthesis and coating elastomeric ligatures with different concentration levels of 1.25, 2.5, 5, 7.5, and 10 % of rGO-nCur, tensile strength, force decay, extension to tensile strength, and contact angle of the coated elastomeric ligatures were measured using universal testing machine and sessile drop method, respectively. To investigate the mechanism through which irradiated rGO-nCur can inhibit the formation of S. mutans biofilms, intracellular reactive oxygen species (ROS) generation, and increase in temperature of rGO-nCur solutions under the 450 and 980 nm laser irradiation, respectively, were measured. The anti-biofilm activity and inhibition of water-insoluble extracellular polysaccharide (EPS) production ability of irradiated rGO-nCur coated elastomeric ligatures using a 450 nm diode laser (195 J/cm2), a 980 nm diode laser (195 J/cm2), and a combination of both (78 J/cm2 of irradiation from each one) (i.e., PDI, PTI, and dual-modal PDI/PTI, respectively) were determined. Also, the expression of virulence genes involved in biofilm formation (comDE, gtfD, and smuT) was assessed by quantitative real-time polymerase chain reaction (RT-qPCR) following the mentioned treatment. One-way ANOVA test and Tukey post-hoc test at a p-value equal to/or less than 0.05 were used to analyze the obtained data.

RESULTS

The synthesis of GO nano-sheets in a layered structure with a thickness of 0.76 nm was confirmed by AFM analysis. FESEM showed that the exfoliated sheet of synthesized GO had several micrometers in lateral size. DLS revealed that the mean particle size and density index of synthesized nCur were 57.47 ± 2.14 nm and 10 % respectively. In DLS analysis, rGO-nCur showed more positive surface charge (24 mV) than the nano-sheets of GO. FESEM confirmed the coating of rGO-nCur on elastomeric ligatures. ANOVA revealed that tensile strength of 1.25, 2.5, and 5 % rGO-nCur coated elastomeric ligatures were not decreased statistically significantly (P > 0.05). Mean tensile strength and recorded force of 7.5 and 10 % rGO-nCur coated elastomeric ligatures decreased significantly after 14 days' immersion in the artificial saliva (P < 0.05). On the 28th day of the study, the mean of the tensile strength of elastomeric ligatures coated with 10 % rGO-nCur (13.03 ± 0.10 N) was recorded as 55.90 % of the initial tensile strength (23.31 ± 0.41 N in uncoated elastomeric ligatures), while the mean tensile strength of elastomeric ligatures coated with 7.5 % rGO-nCur (16.01 ± 0.10 N) was measured as 68.94 % of the initial tensile strength (23.22 ± 0.09 N in uncoated elastomeric ligatures). When comparing the coated elastomeric ligatures at 7.5 % and 10 % to the original uncoated elastomeric ligatures at similar time intervals, statistically significant decreases in extension to tensile strength (0.42 to 0.71 mm or 3.02 to 5.05 %; all P < 0.05) were observed. The largest contact angle was measured in elastomeric ligatures coated by 10 % rGO-nCur followed by 7.5 and 5 % rGO-nCur (128 ± 2.19°, 117 ± 2.23°, and 99 ± 1.83°; respectively). The results revealed a rise of 6.4-fold in intracellular ROS and an 11.2 °C increase in the temperature of rGO-nCur solutions following the 450 nm and 980 nm laser irradiation, respectively. The 5 % rGO-nCur coated elastomeric ligature mediated dual-modal PDI/PTI showed the most inhibition of the biofilm formation of S. mutans by 83.62 % (P = 0.00). Significant reductions in water-insoluble EPS were detected in biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 nm and 980 nm diode lasers (i.e., dual-modal PDI/PTI; 96.17 %; P = 0.00). The expression levels of comDE, gtfD, and smuT virulence genes were significantly downregulated (7.52-, 13.92-, and 8.23-fold, respectively) in the biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following dual-modal PDI/PTI in comparison with biofilm cultures on non-coated elastomeric ligatures.

CONCLUSION

5 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 and 980 nm diode lasers (dual-modal PDI/PTI), without adverse effects on the physico-mechanical properties of elastomeric ligatures, can be used to inhibit the formation of S. mutans biofilms on the coated elastomeric ligatures around orthodontic brackets.

Recent Advances of Tumor Microenvironment-Responsive Nanomedicines-Energized Combined Phototherapy of Cancers

Photodynamic therapy (PDT) has emerged as a powerful tumor treatment tool due to its advantages including minimal invasiveness, high selectivity and thus dampened side effects. On the other side, the efficacy of PDT is severely frustrated by the limited oxygen level in tumors, thus promoting its combination with other therapies, particularly photothermal therapy (PTT) for bolstered tumor treatment outcomes. Meanwhile, nanomedicines that could respond to various stimuli in the tumor microenvironment (TME) provide tremendous benefits for combined phototherapy with efficient hypoxia relief, tailorable drug release and activation, improved cellular uptake and intratumoral penetration of nanocarriers, etc. In this review, we will introduce the merits of combining PTT with PDT, summarize the recent important progress of combined phototherapies and their combinations with the dominant tumor treatment regimen, chemotherapy based on smart nanomedicines sensitive to various TME stimuli with a focus on their sophisticated designs, and discuss the challenges and future developments of nanomedicine-mediated combined phototherapies.

Advancement in Biopolymer Assisted Cancer Theranostics

Applications of nanotechnology have increased the importance of research and nanocarriers, which have revolutionized the method of drug delivery to treat several diseases, including cancer, in the past few years. Cancer, one of the world's fatal diseases, has drawn scientists' attention for its multidrug resistance to various chemotherapeutic drugs. To minimize the side effects of chemotherapeutic agents on healthy cells and to develop technological advancement in drug delivery systems, scientists have developed an alternative approach to delivering chemotherapeutic drugs at the targeted site by integrating it inside the nanocarriers like synthetic polymers, nanotubes, micelles, dendrimers, magnetic nanoparticles, quantum dots (QDs), lipid nanoparticles, nano-biopolymeric substances, etc., which has shown promising results in both preclinical and clinical trials of cancer management. Besides that, nanocarriers, especially biopolymeric nanoparticles, have received much attention from researchers due to their cost-effectiveness, biodegradability, treatment efficacy, and ability to target drug delivery by crossing the blood-brain barrier. This review emphasizes the fabrication processes, the therapeutic and theragnostic applications, and the importance of different biopolymeric nanocarriers in targeting cancer both in vitro and in vivo, which conclude with the challenges and opportunities of future exploration using biopolymeric nanocarriers in onco-therapy with improved availability and reduced toxicity.

Effect of high-intensity laser therapy versus shockwave therapy on selected outcome measures in osteoporotic long-term hemiparetic patients: a randomized control trial

BACKGROUND

This study aimed to compare the effects of high-intensity laser therapy (HILT) and extracorporeal shock wave therapy (ESWT) in treating consequences of osteoporosis in hemiparetic patients.

METHODS

A randomized controlled trial was conducted on hemiplegic patients with osteoporosis. They were randomly classified into three equal groups (n = 40 in each group). The control group received medication and traditional physiotherapy programs for stroke patients. The high-intensity laser (HIL) group received the same intervention as the control group in addition to high-intensity laser therapy. The shock wave (SW) group received the same intervention as the control group in addition to shock wave therapy. The three groups received an intervention that lasted 3 sessions/week for 12 weeks). All groups were assessed before and after therapy for the degree of pain, fall risk, and quality of life.

RESULTS

A statistically significant difference (p < 0.05) was found concerning VAS, which had a significant difference in favor of HILT and ESWT groups compared to the control group; however, no significant difference was determined between HIL and SW groups. Regarding the overall stability index, SFBBS, and QUALEFFO-41, there was a significant difference in favor of HIL and SW groups compared to the control group, and a significant difference was found in HIL when compared to SW.

CONCLUSION

The current study indicates that the combined traditional physical therapy and HILT and ESWT have clinical significance in improving osteoporotic long-term hemiparetic patients with more favor to HILT.

TRIAL REGISTRATION

The study was registered as a clinical trial at ClinicalTrial.gov ID (NCT05616611).

Preparation and characterization of solid lipid nanoparticles incorporating bioactive coumarin analogues as photosensitizing agents

Daphnetin (7,8-dihydroxy-coumarin, DAPH) is a naturally occurring coumarin presenting a wide array of biological activities. In the present study, daphnetin and its novel synthetic analogue 7,8-dihydroxy-4-methyl-3-(4-hydroxyphenyl)-coumarin (DHC) were encapsulated in solid lipid nanoparticles (SLNs) with Encapsulation Efficiency values of 80% and 40%, respectively. Nanoparticles of an average hydrodynamic diameter of approximately 250 nm were formed, showing a good stability in aqueous dispersion (polydispersity index 0.3-0.4), as determined by Dynamic Light Scattering (DLS). The SLNs were also characterized using Fourier Transform-Infrared (FT-IR) spectroscopy and Thermogravimetric Analysis (TGA). TEM images of the blank-SLNs indicated a spherical morphology and a size of 20-50 nm. The release studies of the coumarin analogues indicated a non-Fickian diffusion mechanism, while the release profiles better fitted on the Higuchi kinetic model. Moreover, the coumarin analogues and their SLNs were examined for their antioxidant activity using DPPH and anti-lipid peroxidation assays, exhibiting stronger antioxidant activity when encapsulated than in their free form. The coumarin derivatives and their SLNs were examined for their photodynamic therapy (PDT) efficacy against the human squamous carcinoma A431 cell line, with DHC coumarin both in its free and encapsulated form exhibiting significant PDT activity, reducing the cell viability to 11% after irradiation with a fluence rate of 2.16 J/cm2. Finally, the intracellular localization studies indicated the enhanced cellular uptake of the coumarin analogues when loaded in the SLNs.

Managing Corneal Infections: Out with the old, in with the new?

There have been multiple reports of eye infections caused by antibiotic-resistant bacteria, with increasing evidence of ineffective treatment outcomes from existing therapies. With respect to corneal infections, the most commonly used antibiotics (fluoroquinolones, aminoglycosides, and cephalosporines) are demonstrating reduced efficacy against bacterial keratitis isolates. While traditional methods are losing efficacy, several novel technologies are under investigation, including light-based anti-infective technology with or without chemical substrates, phage therapy, and probiotics. Many of these methods show non-selective antimicrobial activity with potential development as broad-spectrum antimicrobial agents. Multiple preclinical studies and a limited number of clinical case studies have confirmed the efficacy of some of these novel methods. However, given the rapid evolution of corneal infections, their treatment requires rapid institution to limit the impact on vision and prevent complications such as scarring and corneal perforation. Given their rapid effects on microbial viability, light-based technologies seem particularly promising in this regard.

Advanced Light Source Technologies for Photodynamic Therapy of Skin Cancer Lesions

Photodynamic therapy (PDT) is an increasingly popular dermatological treatment not only used for life-threatening skin conditions and other tumors but also for cosmetic purposes. PDT has negligible effects on underlying functional structures, enabling tissue regeneration feasibility. PDT uses a photosensitizer (PS) and visible light to create cytotoxic reactive oxygen species, which can damage cellular organelles and trigger cell death. The foundations of modern photodynamic therapy began in the late 19th and early 20th centuries, and in recent times, it has gained more attention due to the development of new sources and PSs. This review focuses on the latest advancements in light technology for PDT in treating skin cancer lesions. It discusses recent research and developments in light-emitting technologies, their potential benefits and drawbacks, and their implications for clinical practice. Finally, this review summarizes key findings and discusses their implications for the use of PDT in skin cancer treatment, highlighting the limitations of current approaches and providing insights into future research directions to improve both the efficacy and safety of PDT. This review aims to provide a comprehensive understanding of PDT for skin cancer treatment, covering various aspects ranging from the underlying mechanisms to the latest technological advancements in the field.

Photodynamic Therapy for Colorectal Cancer: An Update and a Look to the Future

This review provides an update on the current state of photodynamic therapy (PDT) for colorectal cancer (CRC) and explores potential future directions in this field. PDT has emerged as a promising minimally invasive treatment modality that utilizes photosensitizers and specific light wavelengths to induce cell death in targeted tumor tissues. In recent years, significant progress has been made in understanding the underlying mechanisms, optimizing treatment protocols, and improving the efficacy of PDT for CRC. This article highlights key advancements in PDT techniques, including novel photosensitizers, light sources, and delivery methods. Furthermore, it discusses ongoing research efforts and potential future directions, such as combination therapies and nanotechnology-based approaches. By elucidating the current landscape and providing insights into future directions, this review aims to guide researchers and clinicians in harnessing the full potential of PDT for the effective management of CRC.

Combinations of Photodynamic Therapy with Other Minimally Invasive Therapeutic Technologies against Cancer and Microbial Infections

The rapid rise in research and development following the discovery of photodynamic therapy to establish novel photosensitizers and overcome the limitations of the technology soon after its clinical translation has given rise to a few significant milestones. These include several novel generations of photosensitizers, the widening of the scope of applications, leveraging of the offerings of nanotechnology for greater efficacy, selectivity for the disease over host tissue and cells, the advent of combination therapies with other similarly minimally invasive therapeutic technologies, the use of stimulus-responsive delivery and disease targeting, and greater penetration depth of the activation energy. Brought together, all these milestones have contributed to the significant enhancement of what is still arguably a novel technology. Yet the major applications of photodynamic therapy still remain firmly located in neoplasms, from where most of the new innovations appear to launch to other areas, such as microbial, fungal, viral, acne, wet age-related macular degeneration, atherosclerosis, psoriasis, environmental sanitization, pest control, and dermatology. Three main value propositions of combinations of photodynamic therapy include the synergistic and additive enhancement of efficacy, the relatively low emergence of resistance and its rapid development as a targeted and high-precision therapy. Combinations with established methods such as chemotherapy and radiotherapy and demonstrated applications in mop-up surgery promise to enhance these top three clinical tools. From published in vitro and preclinical studies, clinical trials and applications, and postclinical case studies, seven combinations with photodynamic therapy have become prominent research interests because they are potentially easily applied, showing enhanced efficacy, and are rapidly translating to the clinic. These include combinations with chemotherapy, photothermal therapy, magnetic hyperthermia, cold plasma therapy, sonodynamic therapy, immunotherapy, and radiotherapy. Photochemical internalization is a critical mechanism for some combinations.

Photodynamic Therapy: From the Basics to the Current Progress of N-Heterocyclic-Bearing Dyes as Effective Photosensitizers

Photodynamic therapy, an alternative that has gained weight and popularity compared to current conventional therapies in the treatment of cancer, is a minimally invasive therapeutic strategy that generally results from the simultaneous action of three factors: a molecule with high sensitivity to light, the photosensitizer, molecular oxygen in the triplet state, and light energy. There is much to be said about each of these three elements; however, the efficacy of the photosensitizer is the most determining factor for the success of this therapeutic modality. Porphyrins, chlorins, phthalocyanines, boron-dipyrromethenes, and cyanines are some of the N-heterocycle-bearing dyes' classes with high biological promise. In this review, a concise approach is taken to these and other families of potential photosensitizers and the molecular modifications that have recently appeared in the literature within the scope of their photodynamic application, as well as how these compounds and their formulations may eventually overcome the deficiencies of the molecules currently clinically used and revolutionize the therapies to eradicate or delay the growth of tumor cells.

Choline phosphate lipid-hitchhiked near-infrared BODIPY nanoparticles for enhanced phototheranostics

Phototheranostics integrating optical imaging and phototherapy has attracted extensive attention. Achieving nanophototherapeutics with near infrared (NIR)-light synchronously triggered photodynamic therapy (PDT) and photothermal therapy (PTT) is challenging. Herein, we develop a multifunctional theranostic nanoplatform prepared from the co-assembly of NIR boron dipyrromethene (BODIPY) with a cooperative D-π-A structure of a thiophene-BODIPY core and benzene-diethylamino, and a choline phosphate lipid. The as-fabricated nanoparticles (DBNPs) exhibited desirable NIR absorption, uniform spherical morphology and good colloidal stability. The elaborate molecular design and supramolecular assembly endowed DBNPs with desirable PDT and PTT activities. Upon 808 nm laser irradiation, the DBNPs efficiently generated active singlet oxygen and regional hyperpyrexia, with a photothermal conversion efficiency of 37.6%. The excellent PDT and PTT performance of DBNPs boosted the potent in vitro and in vivo anti-tumor effects. In addition, these nanoparticles manifested their good capability of NIR fluorescence imaging of tumors. Overall, the DBNPs provide a paradigm for delivering hydrophobic phototherapy molecules with phospholipids for enhanced tumor treatment and imaging.

Metronomic Photodynamic Therapy with Conjugated Polymer Nanoparticles in Glioblastoma Tumor Microenvironment

Alternative therapies such as photodynamic therapy (PDT) that combine light, oxygen and photosensitizers (PSs) have been proposed for glioblastoma (GBM) management to overcome conventional treatment issues. An important disadvantage of PDT using a high light irradiance (fluence rate) (cPDT) is the abrupt oxygen consumption that leads to resistance to the treatment. PDT metronomic regimens (mPDT) involving administering light at a low irradiation intensity over a relatively long period of time could be an alternative to circumvent the limitations of conventional PDT protocols. The main objective of the present work was to compare the effectiveness of PDT with an advanced PS based on conjugated polymer nanoparticles (CPN) developed by our group in two irradiation modalities: cPDT and mPDT. The in vitro evaluation was carried out based on cell viability, the impact on the macrophage population of the tumor microenvironment in co-culture conditions and the modulation of HIF-1α as an indirect indicator of oxygen consumption. mPDT regimens with CPNs resulted in more effective cell death, a lower activation of molecular pathways of therapeutic resistance and macrophage polarization towards an antitumoral phenotype. Additionally, mPDT was tested in a GBM heterotopic mouse model, confirming its good performance with promising tumor growth inhibition and apoptotic cell death induction.

Effect of Hypericin-Mediated Photodynamic Therapy on the Secretion of Soluble TNF Receptors by Oral Cancer Cells

Squamous cell carcinoma is the most common cancer of the head and neck region. In addition to the classic surgical treatment method, alternative therapy methods are sought. One such method is photodynamic therapy (PDT). In addition to the direct cytotoxic effect, it is essential to determine the effect of PDT on persistent tumor cells. The study used the SCC-25 oral squamous cell carcinoma (OSCC) cell line and the HGF-1 healthy gingival fibroblast line. A compound of natural origin-hypericin (HY)-was used as a photosensitizer (PS) at concentrations of 0-1 µM. After two hours of incubation with the PS, the cells were irradiated with light doses of 0-20 J/cm². The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test was used to determine sublethal doses of PDT. Cell supernatants subjected to sublethal PDT were assessed for soluble tumor necrosis alpha receptors (sTNF-R1, sTNF-R2). The phototoxic effect was observed starting with a light dose of 5 J/cm² and amplified with the increase in HY concentration and light dose. A statistically significant increase in sTNF-R1 secretion by SCC-25 cells was demonstrated after the PDT with 0.5 µM HY and irradiation with 2 J/cm² (sTNF-R1 concentration = 189.19 pg/mL ± 2.60) compared to the control without HY and irradiated with the same dose of light (sTNF-R1 concentration = 108.94 pg/mL ± 0.99). The baseline production of sTNF-R1 was lower for HGF-1 than for SCC-25, and secretion was not affected by the PDT. The PDT had no effect on the sTNF-R2 production in the SCC-25 or HGF-1 lines.

Suppressing cancer by damaging cancer cell DNA using LED irradiation

BACKGROUND

High-energy irradiation eliminates cancer cells by destroying their genetic components. However, there are several side effects from doing this, such as fatigue, dermatitis, and hair loss, which remain obstacles to this treatment. Here, we propose a moderate method that uses low-energy white light from a light-emitting diode (LED) to selectively inhibit cancer cell proliferation without affecting normal cells.

METHODS

The association between LED irradiation and cancer cell growth arrest was evaluated based on cell proliferation, viability, and apoptotic activity. Immunofluorescence, polymerase chain reaction, and western blotting were performed in vitro and in vivo to identify the metabolism related to the inhibition of HeLa cell proliferation.

RESULTS

LED irradiation aggravated the defective p53 signaling pathway and induced cell growth arrest in cancer cells. Consequently, cancer cell apoptosis was induced by the increased DNA damage. Additionally, LED irradiation inhibited the proliferation of cancer cells by suppressing the MAPK pathway. Furthermore, the suppression of cancer growth by the regulation of p53 and MAPK was observed in cancer-bearing mice irradiated with LED.

CONCLUSIONS

Our findings suggest that LED irradiation can suppress cancer cell activity and may contribute to preventing the proliferation of cancer cells after medical surgery without causing side effects.

Near-infrared phototheranostics of tumors with protoporphyrin IX and chlorin e6 photosensitizers

BACKGROUND

The study aims to develop a method for phototheranostics of tumors in the near-infrared (NIR) range using protoporphyrin IX (PpIX) and chlorin e6 (Ce6) photosensitizers (PSs) MATERIALS AND METHODS: Phototheranostics includes spectral fluorescence diagnostics of PS distribution and photodynamic therapy (PDT) using a single laser in the red spectral range. PpIX and Ce6 fluorescence were registered in the NIR range. PpIX and Ce6 photobleaching was determined during PDT by the change in PS fluorescence. NIR phototheranostics with PpIX and Ce6 were performed on optical phantoms and tumors of patients with oral leukoplakia and basal cell carcinoma.

RESULTS

NIR spectral fluorescence diagnostics of optical phantoms with PpIX or Ce6 is possible when fluorescence is excited by 635 or 660 nm lasers. Fluorescence intensity of PpIX and Ce6 was measured in the range of 725-780 nm. The highest values of signal-to-noise in the case of phantoms with PpIX were observed at λ_exc=635 nm, and for phantoms with Ce6 at λ_exc=660 nm. NIR phototheranostics provides the detection of tumor tissues with PpIX or Ce6 accumulation. The PSs photobleaching in the tumor during PDT occurs according to a bi-exponential law.

CONCLUSION

Phototheranostics of tumors containing PpIX or Ce6 allows fluorescent monitoring of PS distribution in the NIR range and measuring PSs photobleaching during light exposure that provides personalization of the photodynamic exposure duration to deeper tumors. Using a single laser for fluorescence diagnostics and PDT reduces patient treatment time.

Improved Simulated-Daylight Photodynamic Therapy and Possible Mechanism of Ag-Modified TiO2 on Melanoma

Simulated-daylight photodynamic therapy (SD-PDT) may be an efficacious strategy for treating melanoma because it can overcome the severe stinging pain, erythema, and edema experienced during conventional PDT. However, the poor daylight response of existing common photosensitizers leads to unsatisfactory anti-tumor therapeutic effects and limits the development of daylight PDT. Hence, in this study, we utilized Ag nanoparticles to adjust the daylight response of TiO₂, acquire efficient photochemical activity, and then enhance the anti-tumor therapeutic effect of SD-PDT on melanoma. The synthesized Ag-doped TiO₂ showed an optimal enhanced effect compared to Ag-core TiO₂. Doping Ag into TiO₂ produced a new shallow acceptor impurity level in the energy band structure, which expanded optical absorption in the range of 400-800 nm, and finally improved the photodamage effect of TiO₂ under SD irradiation. Plasmonic near-field distributions were enhanced due to the high refractive index of TiO₂ at the Ag-TiO₂ interface, and then the amount of light captured by TiO₂ was increased to induce the enhanced SD-PDT effect of Ag-core TiO₂. Hence, Ag could effectively improve the photochemical activity and SD-PDT effect of TiO₂ through the change in the energy band structure. Generally, Ag-doped TiO₂ is a promising photosensitizer agent for treating melanoma via SD-PDT.

Enzyme-Responsive Double-Locked Photodynamic Molecular Beacon for Targeted Photodynamic Anticancer Therapy

An advanced photodynamic molecular beacon (PMB) was designed and synthesized, in which a distyryl boron dipyrromethene (DSBDP)-based photosensitizer and a Black Hole Quencher 3 moiety were connected via two peptide segments containing the sequences PLGVR and GFLG, respectively, of a cyclic peptide. These two short peptide sequences are well-known substrates of matrix metalloproteinase-2 (MMP-2) and cathepsin B, respectively, both of which are overexpressed in a wide range of cancer cells either extracellularly (for MMP-2) or intracellularly (for cathepsin B). Owing to the efficient Förster resonance energy transfer between the two components, this PMB was fully quenched in the native form. Only upon interaction with both MMP-2 and cathepsin B, either in a buffer solution or in cancer cells, both of the segments were cleaved specifically, and the two components could be completely separated, thereby restoring the photodynamic activities of the DSBDP moiety. This PMB could also be activated in tumors, and it effectively suppressed the tumor growth in A549 tumor-bearing nude mice upon laser irradiation without causing notable side effects. In particular, it did not cause skin photosensitivity, which is a very common side effect of photodynamic therapy (PDT) using conventional "always-on" photosensitizers. The overall results showed that this "double-locked" PMB functioned as a biological AND logic gate that could only be unlocked by the coexistence of two tumor-associated enzymes, which could greatly enhance the tumor specificity in PDT.

Reactive oxygen species-powered cancer immunotherapy: Current status and challenges

Reactive oxygen species (ROS) are crucial signaling molecules that can arouse immune system. In recent decades, ROS has emerged as a unique therapeutic strategy for malignant tumors as (i) it can not only directly reduce tumor burden but also trigger immune responses by inducing immunogenic cell death (ICD); and (ii) it can be facilely generated and modulated by radiotherapy, photodynamic therapy, sonodynamic therapy and chemodynamic therapy. The anti-tumor immune responses are, however, mostly downplayed by the immunosuppressive signals and dysfunction of effector immune cells within the tumor microenvironment (TME). The past years have seen fierce developments of various strategies to power ROS-based cancer immunotherapy by e.g. combining with immune checkpoints inhibitors, tumor vaccines, and/or immunoadjuvants, which have shown to potently inhibit primary tumors, metastatic tumors, and tumor relapse with limited immune-related adverse events (irAEs). In this review, we introduce the concept of ROS-powered cancer immunotherapy, highlight the innovative strategies to boost ROS-based cancer immunotherapy, and discuss the challenges in terms of clinical translation and future perspectives.

Synthesis and characterization of novel Schiff base-silicon (IV) phthalocyanine complex for photodynamic therapy of breast cancer cell lines

BACKGROUND

Photodynamic therapy is an alternative anticancer treatment approach that promises high therapeutic efficacy. In this study, it is aimed to investigate the PDT-mediated anticancer effects of newly synthesized silicon phthalocyanine (SiPc) molecules on MDA-MB-231, MCF-7 breast cancer cell lines, and non-tumorigenic MCF-10A breast cell line.

METHODS

Novel bromo substituted Schiff base (3a), its nitro homolog (3b), and their silicon complexes (SiPc-5a and SiPc-5b) were synthesized. Their proposed structures were confirmed by FT-IR, NMR, UV-vis and MS instrumental techniques. MDA-MB-231, MCF-7 and MCF-10A cells were illuminated at a light wavelength of 680 nm for 10 min, giving a total irradiation dose of 10 j/cm². MTT assay was used to determine the cytotoxic effects of SiPc-5a and SiPc-5b. Apoptotic cell death was analyzed using flow cytometry. Changes in the mitochondrial membrane potential were determined by TMRE staining. Intracellular ROS generation was observed microscopically using H₂DCFDA dye. Colony formation assay and in vitro scratch assay were performed to analyze the clonogenic activity and cell motility. Transwell migration and matrigel invasion analyzes were conducted to observe changes in the migration and invasion status of the cells.

RESULTS

The combination of SiPc-5a and SiPc-5b with PDT exhibited cytotoxic effects on cancer cells and triggered cell death. SiPc-5a/PDT and SiPc-5b/PDT decreased mitochondrial membrane potential and increased intracellular ROS production. Statistically significant changes were detected in cancer cells' colony-forming ability and motility. SiPc-5a/PDT and SiPc-5b/PDT reduced cancer cells' migration and invasion capacities.

CONCLUSION

The present study identifies PDT-mediated antiproliferative, apoptotic, and anti-migratory characteristics of novel SiPc molecules. The outcomes of this study emphasize the anticancer properties of these molecules and suggest that they may be evaluated as drug-candidate molecules for therapeutic purposes.

Erlotinib-Modified BODIPY Photosensitizers for Targeted Photodynamic Therapy

Photodynamic therapy (PDT) is an innovative, non-invasive and highly selective therapeutic modality for tumours and non-malignant diseases. BODIPY based molecules can function as new generation photosensitizers (PSs) in various PDT applications. Despite numerous conjugated PS systems are available, BODIPYs containing erlotinib lagged behind other photosensitizer units. In this study, smart photosensitizers containing BODIPY, erlotinib and hydrophilic units were prepared for the first time, their physicochemical properties and PDT effects were investigated. Compared with non-halogenated compound, halogenated derivatives possessed much lower fluorescence profile as well as the good ROS generation ability under red light. In vitro PDT studies were performed on both healthy (PNT1a) and prostate cancerous cells (PC3) to determine the selectivity of the compounds on cancerous cells and their effects under light. The halogenated conjugates, exposed to low dose of light illumination exhibited potent activity on cancer cell viability and the calculated IC₅₀ values proved the high phototoxicity of the photosensitizers. It was also determined that the PSs have very low dark toxicity and that the light illumination and ROS formation are required for the initiation of the cell death mechanism. As a result, erlotinib modified BODIPYs could serve as promising agents in anticancer photodynamic therapy.

Enhanced Photodynamic Therapy: A Review of Combined Energy Sources

Photodynamic therapy (PDT) has been used in recent years as a non-invasive treatment for cancer, due to the side effects of traditional treatments such as surgery, radiotherapy, and chemotherapy. This therapeutic technique requires a photosensitizer, light energy, and oxygen to produce reactive oxygen species (ROS) which mediate cellular toxicity. PDT is a useful non-invasive therapy for cancer treatment, but it has some limitations that need to be overcome, such as low-light-penetration depths, non-targeting photosensitizers, and tumor hypoxia. This review focuses on the latest innovative strategies based on the synergistic use of other energy sources, such as non-visible radiation of the electromagnetic spectrum (microwaves, infrared, and X-rays), ultrasound, and electric/magnetic fields, to overcome PDT limitations and enhance the therapeutic effect of PDT. The main principles, mechanisms, and crucial elements of PDT are also addressed.

Advanced techniques for performing photodynamic therapy in deep-seated tissues

Photodynamic therapy (PDT) is a promising localized cancer treatment modality. It has been used successfully to treat a range of dermatological conditions with comparable efficacy to conventional treatments. However, some drawbacks limit the clinical utility of PDT in treating deep-seated tumors. Notably, the penetration limitation of UV and visible light, commonly applied to activate photosensitizers, makes PDT incompetent in treating deep-seated tumors. Development in light delivery technologies, especially fiber optics, led to improved clinical strategies for accessing deep tissues for irradiation. However, PDT efficacy issues remained partly due to light penetration limitations. In this review, we first summarized the current PDT applications for deep-seated tumor treatment. Then, the most recent progress in advanced techniques to overcome the light penetration limitation in PDT, including using functional nanomaterials that can either self-illuminate or be activated by near-infrared (NIR) light and X-rays as transducers, and implantable light delivery devices were discussed. Finally, current challenges and future opportunities of these technologies were discussed, which we hope may inspire the development of more effective techniques to enhance PDT efficacy against deep-seated tumors.

Lima K, Alves de Matos P, Tsubone TM, Gonçalves RR, Ferrari JL. Upconversion rare Earths nanomaterials applied to photodynamic therapy and bioimaging

Light-based therapies and diagnoses including photodynamic therapy (PDT) have been used in many fields of medicine, including the treatment of non-oncological diseases and many types of cancer. PDT require a light source and a light-sensitive compound, called photosensitizer (PS), to detect and destroy cancer cells. After absorption of the photon, PS molecule gets excited from its singlet ground state to a higher electronically excited state which, among several photophysical processes, can emit light (fluorescence) and/or generate reactive oxygen species (ROS). Moreover, the biological responses are activated only in specific areas of the tissue that have been submitted to exposure to light. The success of the PDT depends on many parameters, such as deep light penetration on tissue, higher PS uptake by undesired cells as well as its photophysical and photochemical characteristics. One of the challenges of PDT is the depth of penetration of light into biological tissues. Because photon absorption and scattering occur simultaneously, these processes depend directly on the light wavelength. Using PS that absorbs photons on “optical transparency windows” of biological tissues promises deeper penetration and less attenuation during the irradiation process. The traditional PS normally is excited by a higher energy photon (UV-Vis light) which has become the Achilles’ heel in photodiagnosis and phototreatment of deep-seated tumors below the skin. Thus, the need to have an effective upconverter sensitizer agent is the property in which it absorbs light in the near-infrared (NIR) region and emits in the visible and NIR spectral regions. The red emission can contribute to the therapy and the green and NIR emission to obtain the image, for example. The absorption of NIR light by the material is very interesting because it allows greater penetration depth for in vivo bioimaging and can efficiently suppress autofluorescence and light scattering. Consequently, the penetration of NIR radiation is greater, activating the biophotoluminescent material within the cell. Thus, materials containing Rare Earth (RE) elements have a great advantage for these applications due to their attractive optical and physicochemical properties, such as several possibilities of excitation wavelengths – from UV to NIR, strong photoluminescence emissions, relatively long luminescence decay lifetimes (µs to ms), and high sensitivity and easy preparation. In resume, the relentless search for new systems continues. The contribution and understanding of the mechanisms of the various physicochemical properties presented by this system is critical to finding a suitable system for cancer treatment via PDT.

Optical Characterization of Biological Tissues Based on Fluorescence, Absorption, and Scattering Properties

Optical diagnostics methods are significantly appealing in biological applications since they are non-destructive, safe, and minimally invasive. Laser-induced fluorescence is a promising optical spectrochemical analytical technique widely employed for tissue classification through molecular analysis of the studied samples after excitation with appropriate short-wavelength laser light. On the other hand, diffuse optics techniques are used for tissue monitoring and differentiation based on their absorption and scattering characteristics in the red to the near-infrared spectra. Therefore, it is strongly foreseen to obtain promising results by combining these techniques. In the present work, tissues under different conditions (hydrated/dry skin and native/boiled adipose fat) were distinguished according to their fluorescence emission, absorption, and scattering properties. The selected tissues' optical absorption and scattering parameters were determined via Kubelka-Munk mathematical model according to the experimental tissue reflectance and transmittance measurements. Such measurements were obtained using an optical configuration of integrating sphere and spectrometer at different laser wavelengths (808, 830, and 980 nm). Moreover, the diffusion equation was solved for the fluence rate at the sample surface using the finite element method. Furthermore, the accuracy of the obtained spectroscopic measurements was evaluated using partial least squares regression statistical analysis with 0.87 and 0.89 R-squared values for skin and adipose fat, respectively.

Three-dimensional printing of smart constructs using stimuli-responsive biomaterials: A future direction of precision medicine

Three-dimensional (3D) printing, which is a valuable technique for the fabrication of tissue-engineered constructs and biomedical devices with complex architectures, has brought about considerable progress in regenerative medicine, drug delivery, and diagnosis of diseases. However, because of the static and inanimate properties of conventional 3D-printed structures, it is difficult to use them in therapies for active and precise medicine, such as improved tissue regeneration, targeted or controlled drug delivery, and advanced pathophysiological monitoring. The integration of stimuli-responsive biomaterials into 3D printing provides a potential strategy for designing and building smart constructs that exhibit programmed functions and controllable changes in properties in response to exogenous and autogenous stimuli. These features make 3D-printed smart constructs the next generation of tissue-engineered products. In this review, we introduce the prevalent 3D printing techniques (with an emphasis on the differences between 3D printing and bioprinting, and biomaterials and bioink), the working principle of each technique, and the advantages of using 3D printing for the fabrication of smart constructs. Stimuli-responsive biomaterials that are widely used for 3D printing of smart constructs are categorized, followed by a summary of their applications in tissue regeneration, drug delivery, and biosensors. Finally, the challenges and future perspectives of 3D-printed smart constructs are discussed.

Nanophotosensitizers Composed of Phenyl Boronic Acid Pinacol Ester-Conjugated Chitosan Oligosaccharide via Thioketal Linker for Reactive Oxygen Species-Sensitive Delivery of Chlorin e6 against Oral Cancer Cells

Chlorin E6 (Ce6)-incorporated nanophotosensitizers were fabricated for application in photodynamic therapy (PDT) of oral cancer cells. For this purpose, chitosan oligosaccharide (COS) was conjugated with hydrophobic and reactive oxygen species (ROS)-sensitive moieties, such as phenyl boronic acid pinacol ester (PBAP) via a thioketal linker (COSthPBAP). ThdCOOH was conjugated with PBAP to produce ThdCOOH-PBAP conjugates and then attached to amine groups of COS to produce a COSthPBAP copolymer. Ce6-incorporated nanophotosensitizers using the COSthPBAP copolymer were fabricated through the nanoprecipitation and dialysis methods. The Ce6-incorporated COSthPBAP nanophotosensitizers had a small diameter of less than 200 nm with a mono-modal distribution pattern. However, it became a multimodal and/or irregular distribution pattern when H₂O₂ was added. In a morphological observation using TEM, the nanophotosensitizers were disintegrated by the addition of H₂O₂, indicating that the COSthPBAP nanophotosensitizers had ROS sensitivity. In addition, the Ce6 release rate from the COSthPBAP nanophotosensitizers accelerated in the presence of H₂O₂. The SO generation was also higher in the nanophotosensitizers than in the free Ce6. Furthermore, the COSthPBAP nanophotosensitizers showed a higher intracellular Ce6 uptake ratio and ROS generation in all types of oral cancer cells. They efficiently inhibited the viability of oral cancer cells under light irradiation, but they did not significantly affect the viability of either normal cells or cancer cells in the absence of light irradiation. The COSthPBAP nanophotosensitizers showed a tumor-specific delivery capacity and fluorescence imaging of KB tumors in an in vivo animal tumor imaging study. We suggest that COSthPBAP nanophotosensitizers are promising candidates for the imaging and treatment of oral cancers.

Photodynamic therapy for prostate cancer: Recent advances, challenges and opportunities

Over the past two decades, there has been a tendency toward early diagnosis of prostate cancer due to raised awareness among the general public and professionals, as well as the promotion of prostate-specific antigen (PSA) screening. As a result, patients with prostate cancer are detected at an earlier stage. Due to the risks of urine incontinence, erectile dysfunction, etc., surgery is not advised because the tumor is so small at this early stage. Doctors typically only advise active surveillance. However, it will bring negative psychological effects on patients, such as anxiety. And there is a higher chance of cancer progression. Focal therapy has received increasing attention as an alternative option between active monitoring and radical therapy. Due to its minimally invasive, oncological safety, low toxicity, minimal effects on functional outcomes and support by level 1 evidence from the only RCT within the focal therapy literature, photodynamic treatment (PDT) holds significant promise as the focal therapy of choice over other modalities for men with localized prostate cancer. However, there are still numerous obstacles that prevent further advancement. The review that follows provides an overview of the preclinical and clinical published research on PDT for prostate cancer from 1999 to the present. It focuses on clinical applications of PDT and innovative techniques and technologies that address current problems, especially the use of nanoparticle photosensitizers in PDT of prostate cancer.

Novel Short PEG Chain-Substituted Porphyrins: Synthesis, Photochemistry, and In Vitro Photodynamic Activity against Cancer Cells

This work presents the synthesis and characterization of metal-free, zinc (II), and cobalt (II) porphyrins substituted with short PEG chains. The synthesized compounds were characterized by UV-Vis, ¹H and ¹³C NMR spectroscopy, and MALDI-TOF mass spectrometry. The origin of the absorption bands for tested compounds in the UV-Vis range was determined using a computational model based on the electron density functional theory (DFT) and its time-dependent variant (TD-DFT). The photosensitizing activity was evaluated by measuring the ability to generate singlet oxygen (ΦΔ), which reached values up to 0.54. The photodynamic activity was tested using bladder (5637), prostate (LNCaP), and melanoma (A375) cancer cell lines. In vitro experiments clearly showed the structure-activity relationship regarding types of substituents, their positions in the phenyl ring, and the variety of central metal ions on the porphyrin core. Notably, the metal-free derivative 3 and its zinc derivative 6 exerted strong cytotoxic activity toward 5637 cells, with IC₅₀ values of 8 and 15 nM, respectively. None of the tested compounds induced a cytotoxic effect without irradiation. In conclusion, these results highlight the potential value of the tested compounds for PDT application.

WS2/Polyethylene Glycol Nanostructures for Ultra-Efficient MCF-7 Cancer Cell Ablation and Electrothermal Therapy

Developing novel nanostructures and advanced nanotechnologies for cancer treatment has attracted ever-increasing interest. Electrothermal therapy offers many advantages such as high efficiency and minimal invasiveness, but finding a balance between increasing stability of the nanostructure state and, at the same time, enhancing the nanostructure biodegradability presents a key challenge. Here, we modulate the biodegradation process of two-dimensional-material-based nanostructures by using polyethylene glycol (PEG) via nanostructure disrupt-and-release effects. We then demonstrate the development of a previously unreported alternating current (AC) pulse WS₂/PEG nanostructure system for enhancing therapeutic performance. A decrease in cell viability of ∼42% for MCF-7 cells with WS₂/PEG was achieved, which is above an average of ∼25% for current electrothermal-based therapeutic methods using similar energy densities, as well as degradation time of the WS₂ of ∼1 week, below an average of ∼3.5 weeks for state-of-the-art nanostructure-based systems in physiological media. Moreover, the incubation time of MCF-7 cells with WS₂/PEG reached ∼24 h, which is above the average of ∼4.5 h for current electrothermal-based therapeutic methods and with the use of the amount of time harnessed to incubate the cells with nanostructures before applying a stimulus as a measure of incubation time. Material characterizations further disclose the degradation of WS₂ and the grafting of PEG on WS₂ surfaces. These WS₂-based systems offer strong therapeutic performance and, simultaneously, maintain excellent biodegradability/biocompatibility, thus providing a promising route for the ablation of cancer.

Hybrid laser activated phycocyanin/capecitabine treatment of cancerous MCF7 cells

Laser-induced fluorescence is recently used as an efficient technique in cancer diagnosis and non-invasive treatment. Here, the synergic therapeutical efficacies of the Capecitabine (CAP) chemodrug, photosensitive Phycocyanin (PC) and graphene oxide (GO) under laser irradiation were investigated. The therapeutical efficacies of diverse concentrations of CAP (0.001-10 mg/ml) and PC (0.5-10 mg/ml) alone and with laser irradiation on human breast adenocarcinoma (MCF-7) cells were examined. The interactional effects of 100 mW SHG Nd:YAG laser at 532nm and GaAs laser at 808 nm ranging power of 150 mW- 2.2W were considered. The contribution of graphene oxide (GO) in biocompatible concentrations of 2.5-20 ng/ml and thermal characteristics of laser exposure at 808 nm on GO + fluorophores have been studied. The effects of the bare and laser-excited CAP + PC on cell mortality have been obtained. Despite the laser irradiation could not hold up the cell proliferation in the absence of drug interaction considerably; however, the viability of the treated cells (by a combination of fluorophores) under laser exposure at 808 nm was significantly reduced. The laser at 532 nm excited the fluorescent PC in (CAP + PC) to trigger the photodynamic processes via oxygen generation. Through the in-vitro experiments of laser-induced fluorescence (LIF) spectroscopy of PC + CAP, the PC/CAP concentrations of the maximum fluorescence signal and spectral shifts have been characterized. The synergic effects of the laser exposures and (CAP + PC) treatment at different concentrations were confirmed. It has been shown here that the laser activation of (CAP + PC) can induce the mortality of the malignant cells by reducing the chemotherapeutic dose of CAP to avoid its non-desirable side effects and by approaching the minimally invasive treatment. Elevation of the laser intensity/exposure time could contribute to the therapeutic efficacy. Survival of the treated cells with a combination of GO and fluorophores could be reduced under laser exposure at 808 nm compared to the same combination therapy in the absence of GO. This survey could benefit the forthcoming clinical protocols based on laser spectroscopy for in-situ imaging/diagnosis/treatment of adenocarcinoma utilizing PC + CAP + GO.