Facile preparation of toluidine blue-loaded DNA nanogels for anticancer photodynamic therapy

Abstract

Photodynamic therapy (PDT) provides an effective therapeutic option for different types of cancer in addition to surgery, radiation, and chemotherapy. The treatment outcome of PDT is largely determined by both the light and dark toxicity of photosensitizers (PSs), which can be technically improved with the assistance of a drug delivery system, especially the nanocarriers. Toluidine blue (TB) is a representative PS that demonstrates high PDT efficacy; however, its application is largely limited by the associated dark toxicity. Inspired by TB’s noncovalent binding with nucleic acids, in this study, we demonstrated that DNA nanogel (NG) could serve as an effective TB delivery vehicle to facilitate anticancer PDT. The DNA/TB NG was constructed by the simple self-assembly between TB and short DNA segments using cisplatin as a crosslinker. Compared with TB alone, DNA/TB NG displayed a controlled TB-releasing behavior, effective cellular uptake, and phototoxicity while reducing the dark toxicity in breast cancer cells MCF-7. This DNA/TB NG represented a promising strategy to improve TB-mediated PDT for cancer treatments.

Photodynamic Therapy with an Association of Methylene Blue and Toluidine Blue Promoted a Synergic Effect against Oral Squamous Cell Carcinoma

“…The difference observed between groups was statistically significant (p < 0.05). Similar results using TB-PDT were found using breast cancer cell lines, where TB presented an IC 50 value of 1.13 µM in the dark phase and 0.88 µM in the presence of light, reinforcing the advantages of PDT [41]. Despite its already established use in conjunction with other techniques in the field of cancer diagnosis, the use of TB as a photosensitizer for the treatment of oral cancer is not much discussed in the literature [42].…”

“…Despite its already established use in conjunction with other techniques in the field of cancer diagnosis, the use of TB as a photosensitizer for the treatment of oral cancer is not much discussed in the literature [42]. It is also important to report that exposure to PDT without a photosensitizer did not cause loss of cell viability in the three lineages evaluated, suggesting that the phototoxicity must be attributed exclusively to phenothiazine derivatives as previously reported [41,43].…”

“…As revealed in Table 1, the lowest IC50 value found was obtained using the SCC-9 cell line (41.4 µM). The dark toxicity of TB is well characterized in the literature and also associated with undesired side effects, thereby limiting the concentrations and doses that can be used [40][41][42].…”

Rational Design and Evaluation of Photoactive Molecularly Imprinted Nanoparticles for Tetracycline Degradation Under Visible Light

“…To that aim, we chose toluidine blue (TOL), which is a cheap, highly soluble, nontoxic, and well-characterized cationic thiazine dye that generates high yields of singlet oxygen ( 1 O 2 ) in aqueous solution under visible light irradiation (λ max = 628–633 nm) with a type-II photosensitization mechanism . TOL has been extensively used in photodynamic applications either in solution or as part of conjugated nanomaterials, and thereby it is a proven choice to confer photodynamic properties to our molecularly imprinted and non-imprinted materials. − TOL conjugation was achieved through its aromatic amino moiety via EDC/NHS coupling with the carboxyl side chain of AA within the polymers (Figure A). The conjugated materials were thoroughly purified by dialysis to remove the template, unreacted monomers, low molecular weight oligomers, the fraction of non-conjugated TOL, and other reaction byproducts.…”