Victor Borisovich Loshhenov

Photodynamic therapy (PDT) with chlorin-based photosensitizers requires real-time monitoring of photosensitizer distribution and photobleaching to guide treatment, yet existing endoscopic fluorescence systems rely on short-wavelength (375–450 nm) excitation that is spectrally incompatible with 660 nm chlorin e6 (Ce6)-PDT, forcing interruption of therapy for diagnostic imaging. We developed VENERA-red-660, a dual-channel endoscopic system using a single 660 nm laser for simultaneous white-light and Ce6 fluorescence imaging (>670 nm detection) without interrupting irradiation. System sensitivity was validated on optical phantoms (Ce6 0.1–5.0 mg/L), and phototheranostics was performed in patients with basal cell carcinoma (n = 5), vulvar intraepithelial neoplasia grade III (n = 3), and peritoneal carcinomatosis (n = 10) using intravenous chlorin-based photosensitizer. Phantom testing showed a linear fluorescence response (R² = 0.998) down to the lowest tested concentration of 0.1 mg/L. Pre-PDT fluorescence contrast indices confirmed photosensitizer selectivity in all three tumor types, decreasing by 57%, 66%, and 60% after treatment, consistent with photobleaching; continuous intra-PDT monitoring confirmed progressive photobleaching kinetics, and confocal microscopy verified cellular-level Ce6 selectivity. Increased backscattered laser signal after PDT was consistent with treatment-induced changes in tissue optical properties. These pilot findings demonstrate that single-source phototheranostic monitoring is feasible across external and laparoscopic access routes, supporting further evaluation of VENERA-red-660 as a tool for intraoperative PDT dosimetry.

Peritoneal carcinomatosis (PC) is a common, prognostically unfavorable manifestation of advanced gastrointestinal and gynecological malignancies whose treatment is constrained by the blood-peritoneal barrier, which limits drug penetration even when cytoreductive surgery is combined with systemic chemotherapy. This review evaluates current intraperitoneal treatment modalities and emerging technologies for overcoming this limitation, based on recent clinical trials and meta-analyses identified through Scopus and PubMed. We sequentially examine conventional intraperitoneal chemotherapy (IPC); hyperthermic intraperitoneal chemotherapy (HIPEC) in ovarian, gastric, and colorectal cancers, with attention to patient selection and the peritoneal cancer index as determinants of survival benefit; pressurized intraperitoneal aerosol chemotherapy (PIPAC) and its electrostatic precipitation variant (ePIPAC); and photodynamic and photothermal therapy for tumor treatment. Novel strategies are also discussed, including IPC combined with immune checkpoint inhibitors, optical dosimetry, and nanomedicine-based drug delivery as tools for improving treatment precision. Overall, management of PC is transitioning toward a personalized, multimodal approach: HIPEC and PIPAC provide standardized platforms for regional therapy, but future progress depends on integrating advanced drug delivery systems, immunotherapy, and real-time intraoperative monitoring, with standardization of protocols through large multicenter trials remaining a priority for translating these modalities into clinical practice.

Gastrointestinal (GI) cancers account for a quarter of all cancer cases worldwide and are responsible for a third of cancer deaths. One of the characteristic features of GI tissue is its multilayered structure, which, in addition to multiple scattering, complicates optical spectral analysis. The use of spectroscopic diagnostics and photodynamic therapy for the detection and treatment of GI cancer is a rapidly developing field. The method proposed in this paper for layer-by-layer optical properties assessment, suitable for real-time clinical application to the walls of hollow organs, allows us to calculate the absorbed dose layer by layer. This paper proposes a method for recording spectral data in two geometries, diffuse reflectance and transmission, using light delivery from both the external and internal surfaces of the gastrointestinal tract wall. Layer-by-layer assessment of optical properties was performed using a developed algorithm based on the inverse adding–doubling method with initial optical properties values determined using the modified two-stream Kubelka–Munk model with the accuracy equal to 86 ± 13%. The method was approved in clinical conditions. Based on the results of the work, the developed method for assessing the optical properties of multilayered biological tissues exhibited sufficient speed and accuracy for in vivo application to personalize laser-induced therapy by correction of the laser dose.

AIM: to evaluate discrepancies between subjective intraoperative perfusion assessment and qualitative and quantitative ICG fluorescence angiography, as well as the impact of quantitative perfusion assessment on intraoperative surgical decision-making during colorectal resections. PATIENTS AND METHODS: this prospective single-center study included patients aged 18 years and older with histologically confirmed adenocarcinoma of the distal sigmoid colon, rectosigmoid junction, or rectum, who underwent surgery with primary colorectal anastomosis between May and November 2025. No restrictions regarding tumor stage were applied. Intraoperatively, fluorescence angiography with ICG (0.1 mg/kg) was performed. Perfusion was assessed using the UFF-630/675-01-BIOSPEC system with quantitative analysis of fluorescence parameters, including maximum intensity (Imax), time to peak intensity (Tmax), inflow rate, and outflow rate. The primary outcome was the frequency of discrepancies between visual, qualitative, and quantitative perfusion assessment of the colonic wall. Postoperative complications were recorded within 30 days and classified according to the Clavien-Dindo classification, while anastomotic leakage was graded according to the ISREC classification. RESULTS: a total of 20 patients were included in the study. Impaired colonic wall perfusion was identified in 3/20 (15%) patients based on visual assessment, in 3/20 (15%) patients based on qualitative ICG assessment, whereas quantitative analysis revealed signs of reduced perfusion in 6/20 (30%) patients. Subjective perfusion assessment was based on visual signs of blood supply. The presence of bright red bleeding and a visibly pulsatile blood jet were evaluated. The presence of bright red blood alone was considered a doubtful finding, whereas a pulsatile jet of bright red blood was interpreted as a positive result. In the absence of these signs, additional bowel resection was performed prior to ICG assessment. Thus, a discrepancy between subjective visual and quantitative perfusion assessment was observed in 3/20 (15%) patients, and a similar discrepancy between qualitative ICG assessment and quantitative analysis was also observed in 3/20 (15%) patients. Anastomotic leakage occurred in 2/20 (10%) patients, including 1/20 (5%) case of grade A and 1/20 (5%) case of grade B according to the ISREC classification. In both patients, a decrease in Imax to 83% and 87%, respectively, was observed. In one of these patients, visual perfusion assessment was considered adequate, whereas qualitative ICG assessment was classified as weakly positive in both cases. Negative visual and qualitative perfusion assessments were consistent with quantitative findings in 2/20 (10%) patients. CONCLUSION: the preliminary data demonstrate the presence of discrepancies between subjective, qualitative, and quantitative assessment of intestinal wall perfusion. The clinical significance of these findings should be further evaluated in larger prospective studies.

Gastrointestinal (GI) cancers account for a quarter of all cancer cases worldwide and are responsible for a third of cancer deaths. One of the characteristic features of GI tissue is its multilayered structure, which in addition to multiple scattering, complicates optical-spectral analysis. The risk of lymph node metastasis in GI cancer is primarily related to the depth of tumor invasion. The use of spectroscopic diagnostics and photodynamic therapy for the detection and treatment of GI cancer is a rapidly developing field. The method proposed in this paper for layer-by-layer optical properties assessment, suitable for real-time clinical application to the walls of hollow organs, allows for both determining the depth of tumor invasion into the GI organ wall and calculating the absorbed dose layer-by-layer. This paper proposes a method for recording spectral data in two geometries, diffuse reflectance and transmission, using light delivery from both the external and internal surfaces of the gastrointestinal tract wall. Layer-by-layer assessment of optical properties was performed using a developed algorithm based on the inverse adding-doubling method with initial optical properties values determined using the modified two-stream Kubelka-Munk model with the accuracy equal to 86±13%. The method was approbated in clinical conditions. Based on the results of the work, the developed method for assessing the optical properties of multilayered biological tissues exhibited sufficient speed and accuracy for in vivo application to personalize laser-induced therapy by correction of the laser dose.

Background: Photodynamic therapy (PDT) has emerged as a powerful minimally invasive modality for cancer treatment. However, its efficacy as a monotherapy is often limited by oxygen dependence and limited light penetration. Combining PDT with systemic anticancer drug therapies offers a promising strategy to achieve synergistic effects and overcome resistance. Objective: This review aims to provide a systematic analysis of the mechanisms and clinical potential of combining PDT with chemotherapy, targeted therapy, and immunotherapy, focusing on recent advancements and nanotechnology-based delivery systems. Methods: A comprehensive literature search was performed using PubMed and Scopus databases. The analysis focused on peer-reviewed studies published over the last 10 years addressing synergistic molecular pathways, co-delivery nanoplatforms, and clinical trial outcomes. Results: The combination of PDT with chemotherapy enhances drug accumulation via vascular photosensitization and can overcome multi-drug resistance. Integration with immunotherapy, particularly immune checkpoint inhibitors and tumor vaccines, triggers immunogenic cell death (ICD), leading to systemic antitumor responses. Nanotechnology provides a versatile platform for the targeted co-delivery of photosensitizers and pharmacological agents, significantly reducing systemic toxicity. Conclusions: Combined PDT–drug regimens demonstrate superior therapeutic efficacy compared to monotherapies. Future clinical translation requires the standardization of dosimetry and the development of multifunctional nanomedicines to enable personalized treatment protocols.

This study presents a comparative analysis of the effect of methylene blue (MB) loading strategy on the physicochemical and colloidal properties of ethosomes prepared by the cold method. Two synthesis protocols differing in the phase of introduction of the cationic hydrophilic dye were investigated: a classical approach with MB loading into the aqueous phase and an alternative approach involving MB incorporation into the ethanolic lipid phase. It is shown that the loading strategy is a critical technological factor determining vesicle size, encapsulation efficiency, loading capacity, and electrokinetic properties of the systems. The alternative method results in the formation of smaller ethosomes (R_h ≈ 78 nm) compared to the classical protocol (R_h ≈ 96 nm), but is accompanied by a lower encapsulation efficiency (EE ≈ 36% versus 48%). The results indicate that a reduction in vesicle size does not necessarily lead to higher encapsulation of hydrophilic cationic MB and may be associated with a decrease in the total internal aqueous volume as well as an increased contribution of a weakly bound surface-associated dye fraction. Spectral analysis indicates the preservation of a predominantly monomeric form of MB within ethosomes, while differences in ζ-potential suggest distinct localization of the dye within the vesicular systems. Overall, the results highlight the importance of optimizing the loading protocol in the development of ethosomal drug delivery systems for photodynamic therapy and topical applications.

Background/Objectives: Lymph node dissection during surgeries for cervical and endometrial cancer is associated with significant complications and morbidity. Sentinel lymph nodes (SLNs) mapping using indocyanine green (ICG) has become a promising method for reducing surgical invasiveness and improving patient outcomes. However, the optimal protocol for intraoperative fluorescence mapping of SLNs using ICG, especially regarding the timing of imaging after injection, remains to be fully optimized. This study aimed to evaluate the efficacy of real-time near-infrared (NIR) fluorescence SLN mapping at various time intervals and to investigate the photophysical properties of ICG in human lymph to establish a correlation between fluorescence signals and dye concentration. Methods: A prospective study included 20 patients with cervical and endometrial cancer undergoing laparoscopic or laparotomic surgery. Interstitial ICG injection was administered into the cervical stroma. SLN mapping was conducted using the novel VENERA-green endoscopic system (λ_exc = 800 nm, registration of fluorescence in the range of 830–1000 nm). Spectral fluorescence analysis (λ_exc = 650 nm) was conducted on SLNs and optical phantoms containing human lymph with ICG concentrations from 0 to 40 mg/L. The method made it possible to evaluate ICG absorption/emission properties, as well as to quantify concentration-dependent effects. Results: SLNs were successfully detected in all patients. The average detection time was 15 min with a range of 10 to 25 min. Fluorescence intensity of SLNs was significantly higher 10–15 min after ICG injection compared to 20–25 min. Spectral analysis indicated an absorption peak at 804 nm and an emission peak in the 835–855 nm range for ICG in human lymph. A concentration-dependent redshift of the fluorescence peak was observed and accurately modeled using a logarithmic function (R² = 0.99), which allows for the estimation of ICG concentration in tissue. The bilateral detection rate was 77% for laparoscopy and 100% for laparotomy. Metastases were histologically confirmed in only 2.8% (1/36) of the detected SLNs. Conclusions: Intraoperative NIR fluorescence imaging using ICG is a highly sensitive method for real-time SLN mapping in gynecologic oncology. The optimal detection period is 10 to 15 min after cervical injection to achieve maximum ICG fluorescence intensity, compared to 20 to 25 min. The concentration-dependent fluorescence and absorption properties of ICG in lymph provide the basis for the development of quantitative intraoperative monitoring methods that could improve the accuracy of sentinel lymph node biopsy.

Background/Objectives: This work is devoted to the presentation of the intraoperative method for assessing the blood supply to the tracheal tissues in order to minimize the risk of tissue ischemia and necrosis by early diagnosis of bloodstream disorders during surgery. The vascular network supplying the trachea is characterized by collateral blood circulation. However, after the surgical removal of a tracheal tumor, the created anastomosis may be untenable due to insufficient blood supply to the tissues. The consequence of such a disorder may require additional surgical interventions to restore the integrity of the trachea. Based on publicly available information, diffuse reflectance spectroscopy has not previously been used for blood supply assessment in tracheal surgeries. Methods: Light propagation in a four- or six-layer model of the tracheal wall (500–600 nm) was simulated using the Monte Carlo method; in the simulation, the layer thicknesses, levels of oxygen saturation (StO₂) (0–100%), and blood filling (Hb% 0.5–2%) were varied. Intraoperative measurements using diffuse reflectance spectroscopy were performed in 12 patients at three stages of the operation. Results: The simulation showed that when the fiber is placed from the adventitial side, the differences in the diffuse scattered signal with changes in perichondrium saturation are 2.6 ± 1.7%, whereas when placed from the mucosa side, the changes are less than 1%, which means that deeper layers make a greater contribution to the signal with adventitial access. When testing the StO₂ estimation algorithm, the simulation and experiment agree: the measured StO₂ was 56 ± 7%, which is close to the specified level in the simulation. Clinical measurements demonstrated the possibility of recording saturation changes at the stages before and after the anastomosis. Conclusions: According to the results of this study, saturation estimation by diffuse reflectance spectroscopy shows the prospect for assessing the state of tracheal tissues by the level of their blood supply in clinical conditions in real time.

Photodynamic inactivation and antimicrobial photodynamic therapy (PDI/APDT) based on the toxic properties of reactive oxygen species (ROS), which are generated by a number of photoexcited dyes, are promising for preventing and treating infections, especially those associated with drug-resistant pathogens. The negatively charged bacterial cell surface attracts polycationic photosensitizers, which contribute to the vulnerability of the bacterial plasma membrane to ROS. The integrity of the plasma membrane is critical for the viability of the bacterial cell. Polycationic phthalocyanines are regarded as promising photosensitizers due to their high quantum yields of ROS generation (mainly singlet oxygen), high extinction coefficients in the far-red spectral range, and low dark toxicity. For application in PDI/APDT, the wide range of possibilities of modifying the chemical structure of phthalocyanines is particularly valuable, especially by introducing various peripheral and non-peripheral substituents into the benzene rings. Depending on the type and location of such substituents, it is possible to obtain photosensitizers with different photophysical properties, photochemical activity, solubility in an aqueous medium, biocompatibility, and tropism for certain structures of photoinactivation targets. In this study, we tested novel water-soluble Zn (II) phthalocyanines bearing four 4-((diethylmethylammonium)methyl)phenoxy substituents with symmetric and asymmetric charge distributions for photodynamic antibacterial activity and compared them with those of water-soluble octacationic zinc octakis(cholinyl)phthalocyanine. The obtained results allow us to conclude that the studied tetracationic aryloxy-substituted Zn(II) phthalocyanines effectively bind to the oppositely charged cell wall of the Gram-negative bacteria E. coli. This finding is supported by data on bacteria’s zeta potential neutralization in the presence of phthalocyanine derivatives and fluorescence microscopy images of stained bacterial cells. Asymmetric substitution influences the aggregation and fluorescent characteristics but has little effect on the ability of the studied tetracationic phthalocyanines to sensitize the bioluminescent E. coli K12 TG1 strain. Both symmetric and asymmetric aryloxy-substituted phthalocyanines are no less effective in PDI than the water-soluble zinc octakis(cholinyl)phthalocyanine, a photosensitizer with proven antibacterial activity, and have significant potential for further studies as antibacterial photosensitizers.