Though we crossed many milestones in the field of medicine and health care in eradicating some deadly diseases over the past decades, cancer remained a challenge taking the lives of millions of people and having adverse effects on the quality of life of survivors. Chemotherapy and radiotherapy, the two existing major treatment modalities, have severe side effects and patients undergoing these treatments experience unbearable pain. Consequently, clinicians and researchers are working for the alternate treatment regimens, which can provide complete cure with minimum or no side effects. To this end, the present review highlights the major advances and future promises of photodynamic therapy, an emerging and promising therapeutic modality for combating cancer. We delve on various important aspects of photodynamic therapy including principle, mechanism of action, brief history and development of photosensitizers from first generation to the existing third generation, delivery strategies, development or suppression of immunity, combination therapy and future prospects.

Tetrathiafulvalene and dithiafulvalene are thermally stable, versatile and their HOMO–LUMO levels can be easily through molecular engineering to yield metal-free organic dyes for dye-sensitized solar cells, which are not restricted by the availability of natural resources.

Geminiviruses pose serious threat to many economically important crops such as mungbean, tomato, cotton, etc. To devise a specific antiviral strategy at the viral DNA replication level, a hammerhead ribozyme was directed against the mRNA of the replication initiator protein (Rep). Rep is the most important viral protein for the DNA replication of the Mungbean yellow mosaic India virus (MYMIV), a member of the Geminiviridae family. The ribozyme showed $33% cleavage activity on synthetic rep transcript within 1 h under in vitro conditions, whereas the mutant ribozyme, designed to lack the catalytic activity but target the same site, showed no cleavage. The in vivo efficiency of ribozyme was evaluated in Saccharomyces cerevisiae as it can act as a surrogate host for replication of the MYMIV-DNA and lacks RNAi machinery. In the presence of the ribozyme, growth of the yeast cells that are dependent on geminiviral replication was inhibited by 30% and cellular generation time was increased by 2 h. The RT-PCR analysis showed a maximum of about 50% reduction in the rep mRNA level in presence of the ribozyme compared to its noncatalytic mutant control. About 65% decrease in geminiviral DNA replication was observed due to the downregulation of replication initiator protein by the ribozyme. These results raise the possibility of engineering resistance to geminiviruses employing the ribozyme approach.

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The benzimidazole-1,2,3-triazole hybrid 4f selectively interacted with G-quadruplex DNA over duplex DNA, inhibits cell cycle at the G2/M phase, inducing apoptosis, and may be a G-quadruplex DNA groove binder with anticancer activity.