Encapsulated Rose Bengal Enhances the Photodynamic Treatment of Triple-Negative Breast Cancer Cells.

Among breast cancer subtypes, triple-negative breast cancer stands out as the most aggressive, with patients facing a 40% mortality rate within the initial five years. The limited treatment options and unfavourable prognosis for triple-negative patients necessitate the development of novel therapeutic strategies. Photodynamic therapy (PDT) is an alternative treatment that can effectively target triple-negative neoplastic cells such as MDA-MB-231. In this in vitro study, we conducted a comparative analysis of the PDT killing rate of unbound Rose Bengal (RB) in solution versus RB-encapsulated chitosan nanoparticles to determine the most effective approach for inducing cytotoxicity at low laser powers (90 mW, 50 mW, 25 mW and 10 mW) and RB concentrations (50 µg/mL, 25 µg/mL, 10 µg/mL and 5 µg/mL). Intracellular singlet oxygen production and cell uptake were also determined for both treatment modalities. Dark toxicity was also assessed for normal breast cells. Despite the low laser power and concentration of nanoparticles (10 mW and 5 µg/mL), MDA-MB-231 cells experienced a substantial reduction in viability (8 ± 1%) compared to those treated with RB solution (38 ± 10%). RB nanoparticles demonstrated higher singlet oxygen production and greater uptake by cancer cells than RB solutions. Moreover, RB nanoparticles display strong cytocompatibility with normal breast cells (MCF-10A). The low activation threshold may be a crucial advantage for specifically targeting malignant cells in deep tissues.

Ocular surface changes in primary open-angle glaucoma on anti-glaucoma medications versus treatment-naïve patients.

PURPOSE: To examine the ocular surface disease in primary open-angle glaucoma (POAG) patients already on treatment versus POAG patients without treatment. METHODS: A prospective cohort study was conducted on 120 eyes of 60 POAG patients: 60 treatment-naïve eyes (group I) and 60 eyes already on topical anti-glaucoma medications (AGMs) (group II). All patients had filled out the Ocular Surface Disease Index (OSDI) questionnaire and underwent a comprehensive glaucoma workup. Tear break-up time (TBUT) test, Schirmer's test (type I), corneal sensitivity, anterior segment-optical coherence tomography (AS-OCT), and corneal and conjunctival staining were done at day 1, 1 month, 3 months, 6 months, and 12 months follow-up. RESULTS: On presentation, TBUT, Schirmer's test, tear meniscus height (TMH), and tear meniscus depth (TMD) were significantly higher in group I compared to group II. No significant difference was noted in OSDI score, corneal sensitivity, and tear meniscus area (TMA) between the groups on presentation. Both, lissamine green and rose bengal staining, had higher grades in group II compared to group I. Worsening of ocular surface disease was noted in both groups on follow-up. OSDI score, TBUT, Schirmer's test, TMH, and TMD had better values in group I in comparison to group II on follow-up. CONCLUSION: The study has identified glaucoma patients on AGMs to be more affected by dry eye disease (DED) compared to treatment-naive glaucoma patients. We found statistically significant differences in values of TBUT, Schirmer tests, lissamine and rose bengal staining, and AS-OCT parameters at baseline and 3, 6, and 12 months follow-up. OSDI scores showed significant differences at 6 and 12 months of follow-up. We recommend consideration of evaluation and management of DED/ocular surface disease in glaucoma patients on topical AGMs, particularly multiple drugs and doses.

Novel Photodynamic/Photothermal Treatment of Fungal Keratitis Using Rose Bengal-Loaded Polypyrrole-Gold Nanoparticles in Wistar Albino Rats.

Purpose: Fungal keratitis is a potential corneal contagious disease mainly caused by yeast such as Candida albicans and filamentous fungi such as Aspergillus niger. The response of fungal keratitis to standard antifungals is limited by the poor bioavailability, the limited ocular penetration of antifungal drugs, and the development of microbial resistance. Photodynamic therapy using rose bengal (RB) as a photosensitizer was found to be effective in fungal keratitis management; however, the hydrophilicity of RB limits its corneal penetration. Polypyrrole-coated gold nanoparticles (AuPpy NP) were introduced as a nano-delivery system of RB with high loading capacity. It was proved that (RB-AuPpy NP) exhibited a combined photodynamic/photothermal effect. This study aims to use the combined photodynamic/photothermal effect of RB-AuPpy NP as a novel protocol for treating Fungal Keratitis in albino Wistar rats. Methods: The rats were infected by C. albicans and A. niger. Each infected group of rats was subdivided into groups treated by RB followed by radiation (photodynamic only), AuPpy NP followed by radiation (photothermal only), and RB-AuPpy NP followed by radiation (combined photodynamic/photothermal). Histopathological examination and slit lamp imaging were done to investigate the results. Results: The results revealed that 3 weeks post-treatment, the corneas treated by RB-AuPpy NP (combined photodynamic/photothermal effect) exhibited the best improvement compared to other groups. Conclusion: This protocol can be considered a promising one for Fungal Keratitis management that overcomes microbial resistance problems.

Photothrombotic Mouse Models for the Study of Melatonin as a Therapeutic Tool After Ischemic Stroke.

Melatonin is a potent neuroprotective agent which has shown therapeutic effects in animal models of brain injury such as stroke. Currently, there are few effective treatments for the therapeutics of stroke, the second leading cause of death and a major cause of disability worldwide. As demonstrated by the high number of publications during the last two decades, there is growing interest in understanding how and if melatonin could be a possible drug for stroke in humans, given also its very low and limited toxicity. Here, we describe the detailed protocol for performing the photothrombotic model of stroke which involves the occlusion of small cerebral vessels caused by the photoactivation of the previously injected light-sensitive dye Rose Bengal. Importantly, this model allows for the study of cellular and molecular mechanisms underlying the pathophysiology of stroke and thus can be used for investigating the neuropharmacological role of melatonin and the melatonin system in stroke. In particular, future research is warranted to demonstrate how and if melatonin impacts neurodegeneration, neuroprotection, and neuro-regeneration occurring after the brain injury caused by the occlusion of cerebral vessels.

Rose Bengal Photodynamic Antimicrobial Therapy: A Review of the Intermediate-Term Clinical and Surgical Outcomes.

PURPOSE: To evaluate the intermediate-term clinical outcomes of Rose Bengal Photodynamic Antimicrobial Therapy (RB-PDAT) for infectious keratitis; secondarily, to evaluate the surgical outcomes of individuals who underwent optical keratoplasty after RB-PDAT. DESIGN: Retrospective cohort study. METHOD: A retrospective chart review was performed of 31 eyes from 30 consecutive individuals with infectious keratitis refractory to standard medical therapy who underwent RB-PDAT at the Bascom Palmer Eye Institute between January 2016 and July 2020. Data collected included demographics, risk factors for infectious keratitis, microbiological diagnosis, best spectacle-corrected visual acuity (BCVA), clinical outcomes after RB-PDAT, and complication rates post-keratoplasty. RB-PDAT was performed as described in previous studies. Graft survival was evaluated using Kaplan-Meier curves with log-ranks in individuals who underwent keratoplasty after RB-PDAT. RESULTS: The mean age of the study population was 53 ± 18.0 years. In all, 70% were female; 53.3% self-identified as non-Hispanic White and 43.3% as Hispanic. Mean follow-up time was 28.0 ± 14.4 months. Risk factors included contact lens use (80.6%), history of infectious keratitis (19.3%), and ocular surface disease (16.1%). Cultures were positive for Acanthamoeba (51.6%), Fusarium (12.9%), and Pseudomonas (6.5%). Of the individuals with Acanthamoeba infection, 22.5% were treated with concomitant Miltefosine. Clinical resolution was achieved in 77.4% of patients on average 2.72 ± 1.85 months after RB-PDAT, with 22.5% requiring therapeutic penetrating keratoplasties and 54.8% subsequently requiring optical penetrating keratoplasties. At 2 years, the overall probability of graft survival was 78.7%, and the graft failure rate was 21.3%. CONCLUSION: RB-PDAT is a potential adjunct therapy for infectious keratitis that may reduce the need for a therapeutic penetrating keratoplasty. Patients who undergo keratoplasty after RB-PDAT may have a higher probability of graft survival at 1 year postoperatively.

Clinical Outcomes of Rose Bengal Mediated Photodynamic Antimicrobial Therapy on Fungal Keratitis with Their Microbiological and Pathological Correlation.

PURPOSE: To report the clinical outcome of Photodynamic Antimicrobial Therapy (PDAT) with Rose Bengal (RB) used as an early adjuvant therapy in patients with fungal keratitis and their microbiological and pathological correlation. METHODS: Patients with microbiologically confirmed fungal keratitis underwent PDAT-RB along with topical natamycin 5% drops hourly and oral ketoconazole 200 mg twice a day. This was performed by applying rose bengal (0.1%) to the de-epithelialized cornea for 30 minutes, followed by irradiation with a 6 mW/cm2 custom-made green LED source for 15 minutes (5.4 J/cm2). The corresponding fungal isolates were tested in vitro using PDAT-RB and corneal buttons were evaluated for correlation. RESULTS: Following informed consent, seven patients (male-5, female-2, mean age 47.7 years) with fungal keratitis were recruited. There were 3 cases each of Fusarium and Aspergillus flavus and 1 case of Acremonium sp. The average vertical and horizontal diameters of the corneal infiltrate were 4.12 ± 0.55 and 3.99 ± 1.19 mm, respectively. The average depth of corneal involvement was 283 ± 75.27µ as measured by anterior segment OCT. The clinical resolution was achieved in the cases with Fusarium keratitis with an average time of 39 days. Three cases of A. flavus and a single patient with Acremonium keratitis worsened and needed therapeutic keratoplasty (TPK) for resolution. Post-TPK, the corneal tissues grew A. flavus in one out of three cases and Acremonium sp. in one case. In vitro PDAT-RB experiment was performed on the corresponding fungal isolates grown from the corneal scraping. PDAT-RB produced clear inhibition of Fusarium and Acremonium sp. with no effect on the growth of A. flavus. Histopathologically, 2 out of 4 (50%) corneal buttons showed fungal filaments. CONCLUSIONS: While the in vitro and in vivo results of PDAT-RB matched for Fusarium sp. and Aspergillus flavus keratitis being favourable in the former and non-favourable in the latter, these results were discrepant in Acremonium sp.

Fabrication and characterization of chitosan nanoparticles using the coffee-ring effect for photodynamic therapy.

BACKGROUND AND OBJECTIVES: Biocompatible nanoparticles have been increasingly used in a variety of medical applications, including photodynamic therapy. Although the impact of synthesis parameters and purification methods is reported in previous studies, it is still challenging to produce a reliable protocol for the fabrication, purification, and characterization of nanoparticles in the 200-300 nm range that are highly monodisperse for biomedical applications. STUDY DESIGN/MATERIALS AND METHODS: We investigated the synthesis of chitosan nanoparticles in the 200-300 nm range by evaluating the chitosan to sodium tripolyphosphate (TPP) mass ratio and acetic acid concentration of the chitosan solution. Chitosan nanoparticles were also crosslinked to rose bengal and incubated with human breast cancer cells (MCF-7) to test photodynamic activity using a green laser (λ = 532 nm, power = 90 mW). RESULTS: We established a simple protocol to fabricate and purify biocompatible nanoparticles with the most frequent size occurring between 200 and 300 nm. This was achieved using a chitosan to TPP mass ratio of 5:1 in 1% v/v acetic acid at a pH of 5.5. The protocol involved the formation of nanoparticle coffee rings that showed the particle shape to be spherical in the first approximation. Photodynamic treatment with rose bengal-nanoparticles killed ~98% of cancer cells. CONCLUSION: A simple protocol was established to prepare and purify spherical and biocompatible chitosan nanoparticles with a peak size of ~200 nm. These have remarkable antitumor activity when coupled with photodynamic treatment.

Antibacterial Activity of Pharmaceutical-Grade Rose Bengal: An Application of a Synthetic Dye in Antibacterial Therapies.

Rose bengal has been used in the diagnosis of ophthalmic disorders and liver function, and has been studied for the treatment of solid tumor cancers. To date, the antibacterial activity of rose bengal has been sporadically reported; however, these data have been generated with a commercial grade of rose bengal, which contains major uncontrolled impurities generated by the manufacturing process (80-95% dye content). A high-purity form of rose bengal formulation (HP-RBf, >99.5% dye content) kills a battery of Gram-positive bacteria, including drug-resistant strains at low concentrations (0.01-3.13 µg/mL) under fluorescent, LED, and natural light in a few minutes. Significantly, HP-RBf effectively eradicates Gram-positive bacterial biofilms. The frequency that Gram-positive bacteria spontaneously developed resistance to HP-RB is extremely low (less than 1 × 10-13). Toxicity data obtained through our research programs indicate that HP-RB is feasible as an anti-infective drug for the treatment of skin and soft tissue infections (SSTIs) involving multidrug-resistant (MDR) microbial invasion of the skin, and for eradicating biofilms. This article summarizes the antibacterial activity of pharmaceutical-grade rose bengal, HP-RB, against Gram-positive bacteria, its cytotoxicity against skin cells under illumination conditions, and mechanistic insights into rose bengal's bactericidal activity under dark conditions.

Rose Bengal and Future Directions in Larynx Tumor Photodynamic Therapy.

Photodynamic Therapy (PDT) seems to be a promising method in the treatment of larynx tumor tissues. The aim of the present analysis was the study of photosensitizer penetration of larynx tissue associated with the application of PDT in vitro. This study is based on the use of photosensitive compounds Rose Bengal (RB) that selectively accumulate in larynx tissue. The selection of the study group of patients who will undergo surgery in accordance with medical principles was of key importance for the project. Histopathological examination of samples subjected to PDT revealed numerous changes in the morphology of the cancer cells and surrounding tissues. After PDT treatment, the number of tumor cells decreased compared with the cells number before PDT and the arrangement was relatively loose. After PDT with RB the nuclei morphology was incomplete and fragmented. The effects of the applied PDT of larynx in vitro were assessed under an optical microscope. The future directions in larynx tumor PDT with the use of upconversion nanoparticles (UPCNP) is also discussed.

Rose Bengal Photodynamic Antimicrobial Therapy: A Pilot Safety Study.

PURPOSE: To evaluate the in vivo corneal changes after Rose Bengal photodynamic antimicrobial therapy (RB-PDAT) treatment in New Zealand White rabbits. METHODS: Sixteen rabbits were divided into 5 groups. All groups underwent deepithelialization of an 8 mm diameter area in the central cornea. Group 1: balanced salt solution drops only, group 2: 0.2% RB only, group 3: green light exposure (525 nm, 5.4 J/cm2) only, group 4: 0.1% RB-PDAT, and group 5: 0.1% RB-PDAT. All rabbits were followed clinically. Group 5 rabbits were followed using anterior segment optical coherence tomography (AS-OCT) and clinically. On day 35 after initial treatment, 1 rabbit from group 5 was re-exposed to green light (5.4 J/cm2) to evaluate reactivation of the remaining RB dye, and terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling assay was performed on corneal cryosections. RESULTS: Complete reepithelization was observed, and corneas remained clear after treatment in all groups. In group 5, AS-OCT revealed a cross-linking demarcation line. AS-OCT showed RB fluorescence and collagen cross-linking in all treated eyes of group 5 animals after 5 weeks of treatment. Photobleached RB retention in the corneal stroma was corroborated by fluorescence confocal microscopy on frozen sections. There was no evidence of a sustained cytotoxic effect through terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling at 5 weeks. CONCLUSIONS: RB-PDAT with 0.1% RB is a safe procedure. There was no difference clinically and on histopathology compared with control groups. In eyes where RB dye is retained in the corneal stroma after 1 month of treatment, oxidative stress is not evidenced at long term.

Intralesional injection of rose bengal augments the efficacy of gemcitabine chemotherapy against pancreatic tumors.

BACKGROUND: Chemotherapy regimens that include the utilization of gemcitabine are the standard of care in pancreatic cancer patients. However, most patients with advanced pancreatic cancer die within the first 2 years after diagnosis, even when treated with standard of care chemotherapy. This study aims to explore combination therapies that could boost the efficacy of standard of care regimens in pancreatic cancer patients. METHODS: In this study, we used PV-10, a 10% solution of rose bengal, to induce the death of human pancreatic tumor cells in vitro. Murine in vivo studies were carried out to examine the effectiveness of the direct injection of PV-10 into syngeneic pancreatic tumors in causing lesion-specific ablation. Intralesional PV-10 treatment was combined with systemic gemcitabine treatment in tumor-bearing mice to investigate the control of growth among treated tumors and distal uninjected tumors. The involvement of the immune-mediated clearance of tumors was examined in immunogenic tumor models that express ovalbumin (OVA). RESULTS: In this study, we demonstrate that the injection of PV-10 into mouse pancreatic tumors caused lesion-specific ablation. We show that the combination of intralesional PV-10 with the systemic administration of gemcitabine caused lesion-specific ablation and delayed the growth of distal uninjected tumors. We observed that this treatment strategy was markedly more successful in immunogenic tumors that express the neoantigen OVA, suggesting that the combination therapy enhanced the immune clearance of tumors. Moreover, the regression of tumors in mice that received PV-10 in combination with gemcitabine was associated with the depletion of splenic CD11b+Gr-1+ cells and increases in damage associated molecular patterns HMGB1, S100A8, and IL-1α. CONCLUSIONS: These results demonstrate that intralesional therapy with PV-10 in combination with gemcitabine can enhance anti-tumor activity against pancreatic tumors and raises the potential for this strategy to be used for the treatment of patients with pancreatic cancer.

Local and regional therapy for primary and locally recurrent melanoma.

In the vast majority of cases, cutaneous melanoma presents as localized disease and is treated with wide excision and sentinel lymph node biopsy, with shared decision making regarding completion lymph node dissection and adjuvant systemic therapy. The treatment of recurrent and in-transit disease is more complex, with further options for regional and systemic therapies and multiple variables to be factored into decisions. Rates of overall and complete response to regional therapies can be quite high in carefully chosen patients, which limits the need for systemic therapies and their inherent side effects. Ongoing trials aim to assess the efficacy of combination regional and systemic therapies and assist in deciding among these options. This review discusses the treatment of primary melanoma and regional nodal disease and offers an in-depth discussion of options for the treatment of recurrent melanoma and in-transit melanoma.

Development of Glycerol-Rose Bengal-Polidocanol (GRP) foam for enhanced sclerosis of a cyst for cystic diseases.

Polycystic kidney disease (PKD) is a common genetic disorder that results in a proliferating and enlarging cyst and ultimately leads to loss of kidney function. Because an enlarged cyst is a primary factor for limited kidney function, the large cyst is surgically removed by laparoscopic deroofing or sclerosant. This a relatively nascent treatment method entails complications and sometimes fail due to the cyst fluid refilling and infection. This study proposes using a more stable and effective polidocanol foam with glycerol and Rose Bengal (GRP form) to prevent cyst regeneration and irritation, which is caused by the required body movement during the treatment. Specifically, the foam retention time and viscosity were increased by adding glycerol up to 10% (w/v). The GRP form inhibited cellular proliferation and disrupted cellular junctions, e-cadherin, and cyst formation, demonstrated by the LDH, Live and Dead, and re-plating culture assays. The GRP foam was shown to be a safe and effective treatment as a commercial grade polidocanol foam form by an in vivo study in which subcutaneously injected mice injected with commercial 3% polidocanol, and the GRP foam showed no difference in inflammation. Thus, this study provides an advanced polidocanol form by adding glycerol and Rose-Bengal to help existing sclerotherapy.

Iontophoresis-Assisted Rose Bengal and Green Light Corneal Cross-Linking.

PURPOSE: To evaluate the effects of the application of iontophoresis-assisted rose bengal and green light cross-linking (I-RGX) therapy on enucleated rabbit eyes for corneal biomechanical parameters, dye diffusion rates, and green light levels reaching deep tissues and to compare these parameters with a standard rose bengal and green light cross-linking (RGX) therapy. METHOD: Forty-five enucleated rabbit eyes were used in this study. To evaluate biomechanical changes, corneas were divided into the following 4 groups: the control group, the 0.1% rose bengal application group, the RGX group (100 J/cm), and the I-RGX group (100 J/cm). After this, corneal strips were evaluated with a uniaxial extensometer. To assess corneal dye diffusion, postprocedure dye depth was recorded with anterior segment optic coherence tomography. The amount of irradiation passing through the cornea during irradiation with 250 mW/cm irradiation power was measured with a laser power meter at the first, third, and seventh minutes. RESULTS: In the I-RGX-treated group especially, the mean elastic modulus and corneal stiffness values were about 4.7 times higher when compared with the controls and about 2.2 times higher than those in the RGX group. The rose bengal diffusion depth was 26.63% ± 3.84% of the total corneal thickness in the rose bengal drop group, but this value increased to 42.22% ± 4.77% in the iontophoresis group (<0.001). After iontophoresis, an average of 98% of the 100 J/cm green light was kept in the cornea. CONCLUSIONS: I-RGX is a very useful method for increasing corneal biomechanical strength and is highly effective in increasing the amount of corneal dye diffusion into the cornea while also minimalizing the amount of laser passage reaching deeper tissues.

Rose Bengal-Mediated Photodynamic Antimicrobial Treatment of Acanthamoeba Keratitis.

Purpose: To evaluate the in vivo efficacy of rose bengal (RB)-mediated photodynamic antimicrobial therapy (PDAT) for treatment of Acanthamoeba castellanii keratitis (AK). Materials and Methods: An animal (rabbit) AK model was successfully achieved via intrastromal inoculation of a suspension of A. castellanii cells and trophozoites. Prior to RB-PDAT (pre-treatment, day-5), the severity of the induced corneal infection was graded numerically for epithelial defects, stromal edema, neovascularity, and stromal opacity/infiltration. The right eyes of rabbits (n = 18) were divided equally into three groups (n = 6/group): control (no treatment); 0.1% RB+518 nm irradiation (5.4 J/cm2); and 0.2% RB+518 nm irradiation (5.4 J/cm2). On post-treatment day-5, animals were euthanized, after which corneal buttons were excised and submitted for real-time polymerase chain reaction (RT-PCR) analysis. Results: Post-treatment clinical scores of the 0.1 and 0.2% RB groups indicated significant improvement compared to control group scores (pre-treatment clinical scores; 5.17 ± 0.98, 7.50 ± 0.62, and 6.17 ± 0.70 and post-treatment clinical scores; 4.50 ± 0.56, (p = .043), 3.50 ± 0.99 (p = .039), 6.83 ± 1.66 (p = .34), respectively). RT-PCR analysis revealed that the mean cycle threshold (Ct) values were significantly higher in treated-group corneas compared to control-group corneas, with no significant differences between treated-groups (Mean Ct values; 34.33, 34.5, and 29.67 for 0.1 and 0.2% RB, and control groups). There was a statistically significant negative correlation between post-treatment clinical scores and Ct values (r = -0.474, p-value 0.047). Conclusions: Our results demonstrate that RB-PDAT is effective in decreasing the parasitic load and clinical severity of AK.

Rose Bengal-Amphiphilic Peptide Conjugate for Enhanced Photodynamic Therapy of Malignant Melanoma.

Malignant melanoma is an aggressive skin cancer with poor survival outcomes for patients diagnosed at an advanced stage. While targeted serine/threonine-protein kinase B-Raf (BRAF) and immune checkpoint inhibitors have improved survival outcomes for a proportion of these patients, response rates remain variable. There is a need, therefore, for more effective treatments to bolster the options available for melanoma patients. In this manuscript, we covalently attached Rose Bengal (RB) to the amphipathic peptide (AMP) C(KLAKLAK)2 and determined the effectiveness of the resulting RB-C(KLAKLAK)2 conjugate as a photodynamic therapy (PDT) sensitizer. RB-C(KLAKLAK)2-mediated PDT treatment of subcutaneous B16-F10-Luc2 tumors in C57 mice resulted in lesions that were 479% smaller at the end of the study than animals treated with RB-mediated PDT. The synergistic effect between RB and C(KLAKLAK)2 has been attributed to the AMP sensitizing cells to reactive oxygen species (ROS), making them more susceptible to ROS-induced oxidative stress.

Comparison of Photochemical Crosslinking Versus Sutures for Bonding Conjunctival Grafts.

BACKGROUND AND OBJECTIVES: To explore whether Rose Bengal-induced photochemical crosslinking (RB-PCL) can be a replacement for sutures in conjunctival autograft bonding, we compared the safety, operating time, postoperative ocular signs, and inflammatory responses of RB-PCL versus nylon suturing for sealing conjunctival autografts in rabbits. STUDY DESIGN/MATERIALS AND METHODS: Thirty-six New Zealand White rabbits underwent limbal conjunctival autografting using either sutures or RB-PCL to attach conjunctival autografts to the bare sclera. Animals were randomized to one of two groups (18 per group): the suture group or RB-PCL group. Photochemical crosslinking with a wavelength of 532 nm green light with an illumination intensity of 0.6 W/cm2 for 250 seconds (150 J/cm2 ) or suturing was performed followed by light examination at 3, 7, 28 days after surgery to evaluate the healing condition. Rabbits in each group were euthanized on day 3 (n = 6), 7 (n = 6), or 28 (n = 6) postoperatively, and the graft tissues from the surgical site were processed to evaluate inflammatory response by assessing protein levels of tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) as well as histological examination. Cell viability was evaluated by counting both total and dead cells on hematoxylin and eosin (H&E) stained tissue samples from both groups at 3 and 7 days after surgery. The surgery procedure time was recorded and the graft surface temperatures were measured before and after illumination. RESULTS: Photochemical crosslinking effectively secured the limbal conjunctival autograft over an ocular conjunctival defect with no significant difference from the suture group. The time required for this light activated bonding method was ~550 seconds in comparison with the suture method of half hour. The differences of measured temperature on the graft surface before and after RB-PCL treatment were 2.98 ± 0.11°C. The induction of IL-6 and TNF-α protein was remarkably reduced in the RB-PCL group compared with the suture group at 3 and 7 days after surgery. Histology revealed less infiltrated neutrophils were observed in the RB-PCL group than in the suture group at 3 and 7 days postoperatively. Furthermore, the RB-PCL group showed a better healing process with less eye discharge and mild conjunctival congestion. No significant difference in percent dead cells was observed between RB-PCL and suture groups at 3 and 7 days after surgery. CONCLUSIONS: RB-PCL is a promising alternative for bonding the conjunctival autograft with shorter operation time, less inflammation and better healing outcomes compared to conventional suture. Thermal damage and phototoxicity were not observed using the RB-PCL method in bonding conjunctival grafts. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Upconversion System with Quantum Dots as Sensitizer: Improved Photoluminescence and PDT Efficiency.

Upconversion nanoparticles (UCNPs) are prospective platforms for bioimaging and phototherapy, but a critical bottleneck is the limited brightness due to the faint absorptivity of lanthanide ions and the low quantum yield. To circumvent this problem, we herein propose our strategy to reconstruct the energy cascade of UCNPs using semiconductor quantum dots (QDs) as light sensitizer of Nd3+/Yb3+ codoped UCNPs. Ag2Se QDs with strong absorption at 808 nm acted as efficient antenna and transferred their energy to Yb3+ via a resonance energy transfer process, significantly enhancing the luminescence of UCNPs. This nanocomposite was then combined with Rose Bengal and applied for photodynamic therapy. Both in vitro and in vivo studies revealed the introduction of QDs improved the therapeutic performance remarkably. Our study suggests Ag2Se QDs with excellent photophysical properties can be promising agents to overcome the shortcomings of UCNPs and further strengthen their applications.