2026-07-01 | Carbon nanotubes based nano-materials against Acanthamoeba castellanii
Acanthamoeba castellanii is a free-living amoeba that causes diseases such as Acanthamoeba Keratitis (AK) and Acanthamoeba granulomatous encephalitis (AGE), both of which can result in irreversible harm or even death if left untreated. Treating A. castellanii infection is challenging due to its ability to transform into its resistant cysts form when it is in harsh conditions, making complete eradication difficult. Additionally, the sensitive nature of the site of infection requires the treatment to have a low cytotoxicity. Therefore, there is a pressing need to discover improved treatment options. This study evaluates the anti-amoebic properties of Tioconazole (TCZ) and Tioconazole chitosan oxidized multiwalled carbon nanotubes (TCO) and its cytotoxicity to human cells. Various assays were conducted against A. castellanii strain (ATCC 50492) T4 genotype at concentrations ranging from 10 to 100 µg/mL to determine its amoebicidal, amoebistatic, encystation, and excystation effects. The cytotoxicity of TCO against HaCaT cell lines was evaluated using MTT cytotoxicity assay. Both TCZ and TCO exhibited significant amoebicidal and amoebistatic effects at all concentrations tested. However, at the highest concentration tested TCZ lost amoebicidal effectiveness, while TCO maintained its effectiveness. Additionally, TCO showed greater amoebistatic effect then TCZ at 25 µg/mL. Although both TCZ and TCO exhibited inhibitory effect on encystation and excystation, TCO had a significantly weaker effect compared to TCZ. In the cytotoxic assay, both TCZ and TCO exhibited no significant cytotoxic effect. However, at the high concentration TCO displayed significantly lower cytotoxicity then TCZ. This study has shown the potential of TCO as a promising candidate for treating A. castellanii infections, offering effective amoebicidal and amoebistatic properties with lower cytotoxicity.
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2026-06-29 | In Vitro Inhibition of Bacterial Interactions With Acanthamoeba castellanii by a Monoclonal Antibody Against Galactose-Binding Protein.
Introduction Acanthamoeba castellanii causes amoebic keratitis (AK), primarily in contact lens wearers, and severe lesions may require corneal transplantation. Direct contact between the amoeba and the cornea during AK induction is important for the pathogenic process of the amoeba. From a clinical perspective, identifying molecular factors that regulate this contact-dependent interaction is essential for understanding disease progression and for developing preventive or therapeutic strategies for AK. Methods This study analyzed the effect of treatments with galactose and monoclonal antibodies against the galactose-binding protein (GBP) on the interactions between bacteria and A. castellanii. A. castellanii trophozoites were pre-incubated with monosaccharides (galactose, mannose, or glucose; 100 mM) or monoclonal antibodies against GBP for one hour, followed by co-incubation with pathogenic Escherichia coli O157:H7 (one hour) or non-pathogenic E. coli DH5α (four hours). Bacterial association and invasion were quantified using colony-forming unit (CFU)-based assays following cell lysis, and proteolytic activity was evaluated using gelatin zymography. Statistical analysis was performed using Student's t-test, with P<0.05 considered significant. Results The amoeba-bacteria association after the incubation treatment with mannose was 3.4 times lower than with no treatment. However, the association after the galactose treatment was about 0.7 times lower than with no treatment. In particular, incubation with monoclonal antibodies to GBP showed results very similar to those of mannose. E. coli O157:H7's invasion of the amoebae was reduced by about three times as compared to the association reaction. This reduction in invasion suggests that disruption of lectin-mediated binding may limit the ability of pathogenic bacteria to persist within amoebae. The effects of the incubation treatments with monoclonal antibodies against galactose, mannose, and GBP were so similar that they were almost incomparable. E. coli DH5α's association reaction with galactose was slightly lower than that in the monosaccharide-untreated (no treatment) group. However, it was confirmed that monoclonal antibodies against GBP could reduce the amoeba-bacteria association about 3.65 times more than no treatment. The incubation treatment with antibodies to GBP showed an increase in proteolytic enzyme expression to a degree very similar to that of the mannose treatment group. Conclusion Taken together, these findings indicate that GBP plays a key role in contact-dependent interactions relevant to amoebic pathogenicity. Targeting GBP-mediated pathways may represent a clinically meaningful approach to attenuating host tissue damage and microbial interactions associated with AK.
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2026-06-26 | 3D Molded Inserts Fabricated Using a Self-Nanoemulsifying Drug Delivery System (SNEDDS) to Increase Voriconazole and Diclofenac Permeation for the Treatment of Corneal Keratitis.
Acanthamoeba keratitis (AK) and mycotic keratitis (MK) are severe infectious diseases of the cornea. A major challenge to treatment is the poor bioavailability of conventional eye drop formulations, resulting in significant loss of the therapeutic compound. The present study describes the preparation of self-nanoemulsifying drug delivery systems (SNEDDSs) utilizing 3D-molded inserts as a vehicle for the co-delivery of voriconazole (VOR) and diclofenac sodium (DIC). Characterization of the SNEDDS and the 3D-molded inserts involved analysis of droplet size, polydispersity index (PDI), and zeta potential (ZP), followed by an ex vivo transcorneal permeation. Careful optimization of the SNEDDS composition was fundamental for obtaining a nanoemulsion with a droplet size under 100 nm, a PDI below 0.35, and a variable ZP (ranging from -14.6 ± 0.1 to 16.3 ± 2.4 mV). These properties facilitated a marked improvement in voriconazole's solubility and subsequent transcorneal permeability. The investigation of the inserts revealed that the in vitro drug release could be tailored for immediate release or extended release. Moreover, ex vivo permeation studies demonstrated that the inserts delivered voriconazole to the cornea at concentrations more than the minimum inhibitory concentration. This work successfully demonstrates the formulation of a patient-centric, personalized drug delivery platform for the treatment of AK and MK.
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