Plasmonic gold nanorod-aligned scaffolds represent an emerging approach in the treatment of tumors through photothermal therapy, particularly in the context of resection beds where residual cancer cells may persist. These scaffolds leverage the unique optical properties of gold nanorods, which exhibit strong localized surface plasmon resonance (LSPR) when exposed to near-infrared (NIR) light. This interaction converts light energy into heat, enabling precise hyperthermia within the target temperature range of 45–50°C, a critical threshold for inducing cancer cell death while minimizing damage to surrounding healthy tissue.
The design of these scaffolds involves the alignment of gold nanorods within a biocompatible matrix, often composed of polymers or hydrogels, to create a three-dimensional structure that can be implanted at the tumor resection site. The alignment is crucial as it enhances the collective plasmonic effect, ensuring uniform heat distribution when irradiated. Gold nanorods are preferred due to their tunable LSPR peaks, which can be adjusted to the NIR window (700–900 nm), a region where biological tissues exhibit minimal absorption and scattering, allowing deeper penetration of light.
Localized hyperthermia within the 45–50°C range is particularly effective for inducing irreversible cellular damage in residual tumor cells. At these temperatures, proteins denature, membrane integrity is compromised, and apoptosis pathways are activated. Importantly, this thermal threshold spares most healthy cells, which typically withstand temperatures up to 45°C without significant harm. The precision of this approach is further enhanced by the ability to functionalize gold nanorods with targeting ligands, such as antibodies or peptides, that selectively bind to cancer stem cells (CSCs). CSCs are often responsible for tumor recurrence due to their resistance to conventional therapies, making their targeted elimination a priority.
The scaffolds are engineered to respond to NIR light exposure with rapid temperature elevation, reaching the therapeutic window within seconds. Studies have demonstrated that maintaining this temperature for 5–10 minutes is sufficient to achieve near-complete ablation of residual cancer cells in preclinical models. The photothermal conversion efficiency of gold nanorods, often exceeding 80%, ensures minimal energy waste and reduces the required irradiation time, further protecting adjacent healthy tissue.
Following photothermal treatment, the scaffold’s role transitions to supporting tissue regeneration. The biocompatible matrix can be designed to degrade gradually, releasing growth factors or providing structural support for infiltrating healthy cells. In some designs, the scaffold incorporates extracellular matrix (ECM)-mimicking components to promote cell adhesion and proliferation. The gold nanorods themselves, being inert and biocompatible, do not impede healing and can remain embedded without eliciting significant immune responses.
A critical advantage of this approach is the ability to perform repeated treatments if residual cancer cells are detected post-resection. The scaffolds can be re-irradiated as needed, offering a non-invasive method to address recurrence without additional surgical intervention. This adaptability is particularly valuable in cases where tumor margins are unclear or where CSCs persist despite initial therapy.
The integration of imaging modalities with these scaffolds further enhances their utility. For instance, the strong optical absorption and scattering properties of gold nanorods allow for real-time monitoring using techniques like photoacoustic imaging, ensuring accurate placement and irradiation. This theranostic capability ensures that the treatment is both precise and verifiable, reducing the risk of under- or over-treatment.
In summary, plasmonic gold nanorod-aligned scaffolds provide a multifaceted solution for post-resection tumor treatment. By combining targeted hyperthermia with regenerative support, they address two major challenges in oncology: eliminating residual cancer cells, particularly CSCs, and promoting the restoration of healthy tissue. The precision of photothermal therapy, confined to the 45–50°C range, ensures efficacy while preserving surrounding structures, making this a promising strategy for improving outcomes in tumor resection cases.
Future developments may focus on optimizing scaffold composition for specific cancer types, refining targeting strategies to further enhance specificity, and integrating advanced imaging techniques for real-time feedback. The continued exploration of gold nanorod-based platforms holds significant potential for advancing localized cancer therapies and improving patient recovery.