V.K. Sanju

A significant study and review led by Malayali scientists regarding Squaraine dyes is garnering attention for its potential to revolutionize the field of biophotonics. The study highlights that these dyes hold immense possibilities in molecular sensing, bioimaging, and theranostics, which can aid in the early detection and effective treatment of deadly diseases like cancer.

Squaraines are organic dyes with a unique ability to absorb and emit light (fluorescence) near the infrared spectrum. The near-infrared (NIR) rays they emit can penetrate deep into body tissues, allowing for a clearer observation of internal biological processes.

The review was led by Dr. A. Ajayaghosh, SSB Chair Professor, and Dr. S. Sreejith, Research Assistant Professor, both from the SRM Institute of Science and Technology, Chennai, who have been researching this branch of science for years. Research Assistant Professor Dr. B. Vedhanarayanan and research scholar C. Sanjay were also part of the team.

These four Malayalis are among the few scientists in India conducting research in this specific field. The research paper has been published in 'Chemical Society Reviews' (Impact Factor 39.3), a prestigious journal of the Royal Society of Chemistry, London.

Diagnosis: Squaraine dyes can detect changes in blood proteins, enzymes, and DNA with extreme precision.

Bioimaging: Using Squaraine dyes allows for capturing images of cells and tissues with greater clarity than current testing methods. The study explains how this can accurately identify tumors during surgery and how it can be utilized for both diagnosis and treatment.

Cancer Treatment: These dyes are expected to bring major breakthroughs in Photodynamic Therapy and Photothermal Therapy, which use light to destroy cancer cells.

Drug Delivery: Researchers found that Squaraine dyes are effective in Targeted Drug Delivery, a technology used to deliver medication specifically to diseased cells.

Our skin and tissues have a high capacity to absorb visible light, making it difficult to capture images inside the body using ordinary light. However, Squaraine dyes emit light in the NIR region (700 to 900 nanometers). Light at this wavelength can travel through tissues without obstruction, helping doctors see internal organs and tumors very clearly.

Precision in Diagnosis

Squaraine dyes function like sensors. When specific types of enzymes or proteins are present in the body, these dyes undergo changes in color or light emission. For instance, they can identify proteins like albumin and enzymes like chymotrypsin in the blood, which is crucial for detecting early symptoms of diseases, including cancer.

Photodynamic Therapy

This is one of the most modern methods in cancer treatment. When Squaraine dyes reach cancer cells, they are targeted with external laser light. At this point, the dyes break down oxygen within the cells, destroying only the cancer cells while protecting other healthy cells. This method can help reduce the side effects of chemotherapy.

Integrated Diagnosis and Treatment

Theranostics is a technology that combines diagnosis and therapy. Using Squaraine dyes, it is possible to locate tumors and simultaneously deliver drugs to destroy them at the exact site. This is known as a multi-modal approach. Researchers emphasize that future advanced treatments will rely on this multi-modal method.

Overcoming Obstacles

Squaraine dyes typically have low solubility in water, which was a major hurdle for their use in the human body. However, the new study describes methods to make these dyes water-soluble. By converting them into nanoparticle forms, they can be used more effectively.

Fluorescence-Guided Surgery

These dyes help distinguish tumor areas with precision during surgery. This reduces the likelihood of tumor cells remaining in the body and increases the success rate of the surgery.

Over the years, Squaraine dyes have evolved from simple fluorescent molecules into multifunctional platforms playing a key role in diagnosis and treatment. Researchers point out that if growth in squaraine chemistry focuses on shaping next-generation biophotonic materials and technologies, it will pave the way for advancements in disease monitoring and personalized medicine.

It is expected that these findings and the review will help develop cost-effective cancer treatment methods without side effects in the future.