A photothermal surface modified with polyelectrolyte multilayers for gene transfection and cell harvest

Gene transfection, which involves introducing nucleic acids into cells, is a pivotal technology in the life sciences and medical fields, particularly in gene therapy. Surface-mediated transfection, primarily targeting cells adhering to surfaces, shows promise for enhancing cell transfection by localizing and presenting surface-bound nucleic acids directly to the cells. However, optimizing endocytosis for efficient delivery remains a persistent challenge. Additionally, ensuring efficient and non-traumatic cell harvest capability is crucial for applications such as ex vivo cell-based therapy. To address these challenges, we developed a photothermal platform with enzymatic degradation capability for efficient gene transfection and cell harvest. This platform is based on carbon nanotubes (CNTs) doped with poly(dimethylsiloxane) and modified with polyelectrolyte multilayers (PEMs) containing hyaluronic acid and quaternized chitosan, allowing for substantial loading of poly(ethyleneimine)/plasmid DNA (pDNA) complexes through electrostatic interactions. Upon irradiation of near-infrared laser, the photothermal properties of CNTs enable high transfection efficiency by delivering pDNA into attached cells via a membrane disruption mechanism. The engineered cells can be harvested by treating with a non-toxic hyaluronidase solution to degrade PEMs, thus maintaining good viability for further applications. This platform has demonstrated remarkable efficacy across various cell lines (including Hep-G2 cells, Ramos cells and primary T cells), achieving a transfection efficiency exceeding 95 %, cell viability exceeding 90 %, and release efficiency surpassing 95 %, highlighting its potential for engineering living cells.