Enhanced non-linear optical properties of porphyrin-based polymers covalently functionalized with graphite phase carbon nitride

In our work, a flurry of original porphyrin-based polymers covalently functionalized g-C₃N₄ nanohybrids were constructed and nominated as PPorx-g-C₃N₄ (x = 1, 2 and 3) through click chemistry between porphyrin-based polymers with alkyne end-groups [(PPorx-C≡CH (x = 1, 2 and 3)] and azide-functionalized graphitic carbon nitride (g-C₃N₄-N₃). Due to the photoinduced electron transfer (PET) between porphyrin-based polymers [PPorx (x = 1, 2 and 3)] group and graphite phase carbon nitride (g-C₃N₄) group in PPorx-g-C₃N₄ nanohybrids, the PPorx-g-C₃N₄ nanohybrids exhibited better non-linear optical (NLO) performance than the corresponding PPorx-C≡CH and g-C₃N₄-N₃. It found that the imaginary third-order susceptibility (Im [χ⁽³⁾]) value of the nanohybrids with different molecular weight (MW) of the pPorx group in the nanohybrids ranged from 2.5×10³ to 7.0 × 10³ g mol^-1 was disparate. Quite interestingly, the Im [χ⁽³⁾] value of the nanohybrid with a pPorx group's MW of 4.2 × 10³ g mol^-1 (PPor2-g-C₃N₄) was 1.47 × 10^-10 esu, which exhibited the best NLO performance in methyl methacrylate (MMA) of all nanohybrids. The PPorx-g-C₃N₄ was dispersed in polymethyl methacrylate (PMMA) to prepare the composites PPorx-g-C₃N₄/PMMA since PMMA was widely used as an alternative to glass. PPor2-g-C₃N₄/PMMA showed the excellent NLO performance of all nanohybrids with the Im [χ⁽³⁾] value of 2.36 × 10^-10 esu, limiting threshold of 1.71 J/cm², minimum transmittance of 8% and dynamic range of 1.09 in PMMA, respectively. It suggested that PPorx-g-C₃N₄ nanohybrids were potential outstanding NLO materials.

Nanomaterials for photothermal and photodynamic cancer therapy

In recent years, the role of optically sensitive nanomaterials has become powerful moieties in therapeutic techniques and has become particularly emphasized. Currently, by the extraordinary development of nanomaterials in different fields of medicine, they have found new applications. Phototherapy modalities, such as photothermal therapy (PTT) by toxic heat generation and photodynamic therapy (PDT) by reactive oxygen species, are known as promising phototherapeutic techniques, which can overcome the limitations of conventional protocols. Moreover, nanomaterial-based PDT and PTT match the simultaneous immune therapy and increase the immune system stimulation resulting from the denaturation of cancer cells. Nevertheless, nanomaterials should have sufficient biocompatibility and efficiency to meet PDT and PTT requirements as therapeutic agents. The present review focuses on the therapeutic potency of PDT, PTT, and also their combined modalities, which are known alternative protocols with minimal morbidity integrated into gold standard treatments such as surgery, chemotherapy, and radiation therapy at tumor treatment and cancer-related infectious diseases. In addition, for deeper understanding, photoablation effects with emphasis on the nature, morphology, and size of photosensitive nanomaterials in PDT and PTT were studied. Finally, transportation techniques and moieties needed as carriers of photosensitizers and photothermal therapy agents to hard-accessed regions, for example, cancerous regions, were investigated.