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Structure-Activity Relationships of Photoswitchable Diarylethene-Based β-Hairpin Peptides as Membranolytic Antimicrobial and Anticancer Agents
摘要： Five series (28 structures) of photoswitchable β-hairpin peptides were synthesized, based on the cyclic scaffold of the natural antibiotic gramicidin S. Cell-type selectivity was compared for all activated (diarylethene ring-open) and deactivated (closed) forms in terms of antibacterial activity (MIC against E. coli and B. subtilis), anticancer activity (IC50 against HeLa cell line), and hemolytic cytotoxicity (HC50 against human erythrocytes). Correlations between the conformational plasticity of the peptides, their hydrophobicity and their bioactivity were also analyzed. Considerable improvements in selectivity were achieved compared to the reference compound. We found a dissociation of the anticancer activity from hemolysis. Phototherapeutic indices (PTI) – HC50(closed)/MIC(open) and HC50(closed)/IC50(open) – were introduced for the peptides as safety criteria. The highest PTI for HeLa-selective toxicity were observed among analogues containing hydroxyleucine on the hydrophobic face. For one compound, high PTIs were demonstrated across a range of different cancer cell lines, including a doxorubicin-resistant one.
关键词： photoswitchable diarylethene-based β-hairpin peptides,antimicrobial,phototherapeutic indices,gramicidin S,anticancer,hemolytic cytotoxicity
更新于2025-09-23 15:21:01
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Topography-guided transepithelial phototherapeutic keratectomy to treat a partial laser in?situ keratomileusis flap amputation over the visual axis
摘要： We describe the use of topography-guided transepithelial phototherapeutic keratectomy (PTK) to restore excellent uncorrected distance visual acuity (UDVA) in an eye with extremely irregular topography as a result of a severe complication during laser in situ keratomileusis (LASIK) flap creation. Three months before the patient presented to our clinic, the microkeratome cut outward during LASIK flap creation, amputating the partially cut flap across the visual axis. Without a flap cut into the preserved one half of the cornea, complete flap amputation was not considered a safe option. Topography-guided transepithelial PTK was used to regularize the cornea and treat the resulting irregular astigmatism. Six months postoperatively, the cornea remained stable and the UDVA was 6/6C2.
关键词： flap amputation,PTK,LASIK,irregular astigmatism,topography-guided transepithelial phototherapeutic keratectomy
更新于2025-09-12 10:27:22
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Highly Stable and Multifunctional Aza-BODIPY-Based Phototherapeutic Agent for Anticancer Treatment
摘要： Phototherapy, as an important class of noninvasive tumor treatment methods, has attracted extensive research interest. Although a large amount of the near-infrared (NIR) phototherapeutic agents have been reported, the low efficiency, complicated structures, tedious synthetic procedures, and poor photostability limit their practical applications. To solve these problems, herein, a donor?acceptor?donor (D?A?D) type organic phototherapeutic agent (B-3) based on NIR aza-boron-dipyrromethene (aza-BODIPY) dye has been constructed, which shows the enhanced photothermal conversion efficiency and high singlet oxygen generation ability by simultaneously utilizing intramolecular photoinduced electron transfer (IPET) mechanism and heavy atom effects. After facile encapsulation of B-3 by amphiphilic DSPE?mPEG5000 and F108, the formed nanoparticles (B-3 NPs) exhibit the excellent photothermal stabilities and reactive oxygen and nitrogen species (RONS) resistance compared with indocyanine green (ICG) proved for theranostic application. Noteworthily, the B-3 NPs can remain outstanding photothermal conversion efficiency (η = 43.0%) as well as continuous singlet oxygen generation ability upon irradiation under a single-wavelength light. Importantly, B-3 NPs can effectively eliminate the tumors with no recurrence via synergistic photothermal/photodynamic therapy under mild condition. The exploration elaborates the photothermal conversion mechanism of small organic compounds and provides a guidance to develop excellent multifunctional NIR phototherapeutic agents for the promising clinical applications.
关键词： heavy atom effects,intramolecular photoinduced electron transfer,donor?acceptor?donor type,NIR phototherapeutic agents,aza-BODIPY
更新于2025-09-10 09:29:36
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Near-infrared excited cooperative upconversion in luminescent Ytterbium(ΙΙΙ) bioprobes as light-responsive theranostic agents
摘要： Near-infrared (NIR) Ytterbium(III) complexes namely [Yb(dpq)(DMF)2Cl3] (1), [Yb(dppz)(DMF)2Cl3] (2), [Yb(dpq)(ttfa)3] (3) and [Yb(dppz)(ttfa)3] (4) based on photosensitizing antenna: dipyrido-[3,2-d:2’,3’-f]-quinoxaline (dpq), dipyrido-[3,2-a:2′,3′-c]-phenazine (dppz) and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Httfa), were designed as NIR bioimaging agents utilizing cooperative upconversion luminescence (CUCL) of Yb(III). Their structures, detailed photophysical properties, biological interactions, photo-induced DNA cleavage, NIR photocytotoxicity and cellular internalization and bioimaging properties were examined. Discrete mononuclear complexes adopt a seven-coordinated {LnN2O2Cl3} mono-capped octahedron (1, 2) and eight-coordinated {LnN2O6} distorted square antiprism geometry (3, 4) with bidentate N, N-donor dpq, dppz and O,O-donor ttfa ligands. The designed Yb(III) probes (3, 4) having advantages of dual sensitizing antennae (dpq/dppz and Httfa) to modulate the desirable optical properties in NIR region for bioimaging in biologically transparent window and light-responsive intracellular damage with spatiotemporal control. The lack of inner-sphere water (q = 0), remarkable photostability, large Stokes’ shifts, presence of energetically rightly poised ligand 3T states allows efficient energy transfer (ET) to the emissive 2F5/2 state of Yb(III). The unique cooperative upconversion luminescence (CUCL) of Yb(III) was observed in 1-4 in the visible blue region (λem = 490 nm) upon NIR excitation at 980 nm, makes them special candidates for NIR-to-visible or NIR-to-NIR cellular imaging probes. The CUCL property of Yb(III) were observed in the discrete mononuclear complexes both in solid state and solution. We elegantly utilized this remarkable property of Yb(III) for cellular imaging application for the first time to the our knowledge including potential uses in CUC/multiphoton excitation microscopy. The complexes exhibit significant binding propensity to DNA, HSA and BSA (K ~ 105 M-1). They effectively cleave supercoiled (SC) DNA to its nicked circular (NC) form at 365 nm via photoredox pathways. The cellular uptake studies evidently displayed cytosolic and nuclear localization of the complexes. Finally, the capability of Yb(III) complexes usage for PDT were demonstrated through significant near-IR photocytotoxicity at 980 nm CW laser. The results depicted here offers an intelligent strategy towards developing light-responsive highly photostable Yb(III) probes for NIR theranostic application in the biologically transparent phototherapeutic window.
关键词： Cooperative upconversion luminescence,NIR photocytotoxicity,NIR cellular imaging,Phototherapeutic,NIR excitation,Ytterbium
更新于2025-09-09 09:28:46
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Recurrent rates and risk factors associated with recurrent painful bullous keratopathy after primary phototherapeutic keratectomy
摘要： Objective: To assess the recurrent rate, mean survival time, and risk factors associated with recurrent painful bullous keratopathy (BK) after primary treatment with phototherapeutic keratectomy. Methods: Medical records from 72 patients (72 eyes) who had phototherapeutic keratectomy for painful BK were evaluated. Data for sex, age, duration of BK, associated ocular and systemic diseases (hypertension, diabetes mellitus, ischemic heart disease, asthma, dyslipidemia, and rheumatoid arthritis), frequency and degree of pain (grade 1–3), visual acuity, corneal thickness, intraocular pressure, and laser setting were extracted and analyzed. Results: The mean age of the patients was 64.2±11.4 years. The mean preoperative duration of BK was 15.0±11.0 months. Most patients had pseudophakic BK (69.40%). Majority of the cases had grade 3 degree of pain (48.60%). Glaucoma and hypertension were markedly found among these patients (51.40% and 19.40%, respectively). Preoperative mean intraocular pressure and corneal thickness were 13.70±4.95 mmHg and 734.1±83.80 μm, respectively. The mean laser diameter and depth were 8.36±1.22 mm and 38.89±8.81 μm, respectively. Systemic disease was significantly associated with the risk for developing recurrent painful BK (P=0.022, hazard ratio [HR] 1.673, 95% confidence interval [CI] 1.08–2.58). The overall recurrent rate was 51%. The average duration time of recurrent painful BK was 17.3±12.9 months (range 1–50 months). The median survival time before recurrence was 29.0±6.6 months. Conclusion: Systemic disease was found to be the only risk factor significantly associated with the development of recurrent painful BK. Low recurrent rate and long mean survival time showed that phototherapeutic keratectomy was effective in relieving recurrent painful BK and can be used as an alternative procedure for patients waiting for corneal transplantation.
关键词： mean survival time,phototherapeutic keratectomy,PTK,recurrent painful,bullous keratopathy,risk factor
更新于2025-09-04 15:30:14