SERS-guided photodynamic therapy: pioneering strategies in advanced cancer diagnosis and treatment

Cancer remains a leading cause of mortality worldwide, and while advances in conventional therapies such as chemotherapy, radiotherapy, and targeted therapies have improved patient outcomes, these treatments often fail to meet the demand for precision and specificity. Many current therapies struggle with limitations such as non-specific targeting, drug resistance, and significant side effects, often leading to incomplete tumor eradication and damage to surrounding healthy tissues. The urgent need for more precise, minimally invasive, and efficient cancer treatment strategies has paved the way for novel therapeutic approaches. Cancer theranostics has evolved exceptionally by incorporating new diagnostic tools that ultimately improve the therapeutic outcome of the treatment. Surface Enhanced Raman Spectroscopy (SERS)-guided photodynamic therapy (PDT) is rapidly gaining attention as a highly sophisticated modality in cancer theranostics, offering a dual advantage of enhanced diagnostic precision and effective therapeutic action. SERS, an ultra-sensitive molecular imaging technique, provides real-time, high-resolution detection of cancer biomarkers, enabling precise tumor localization and characterization. SERS-based theranostic probes can show potential results in both in-vivo and in-vitro studies. Herein this review critically discusses the key roles of SERS during the PDT treatment and also focuses on providing brief information on the fundamentals of both SERS and PDT. In combination with PDT, which selectively destroys cancer cells through photosensitizer activation under light exposure, SERS-guided PDT ensures a targeted therapeutic approach that minimizes damage to surrounding healthy tissues and reduces side effects.