Design of an artificial natural killer cell mimicking system to target tumour cells.

NK cell mimics are assemblies of a cell membrane and a template that replicate biomimetic features and physicochemical properties, respectively. To develop this targeted drug delivery system, gelatin microspheres (cG) were fabricated using a water-in-oil emulsion and reinforced via DMTMM cross-linking to exhibit tunable Young's modulus, a critical parameter for cell-material interactions. These microspheres were subsequently coated with membranes derived from the human NK cell line KHYG-1 to form biomimetic NK cell mimics (cGCM), combining physicochemical control with bioinspired functionality. These engineered cGCM were non-toxic, non-inflammatory, and capable of reducing macrophage uptake by ~10% when incubated with differentiated THP-1 cells. In vitro studies demonstrated significant interaction/ proximity of the cGCM with cancer cells in 2D cultures of breast cancer cells (MDA-MB-231), 3D spheroids of liver (HepG2), and colon (HT-29) cancer cell models, and a zebrafish breast cancer xenograft (MDA-MB-231) model. The cGCM also evaded macrophage detection in a Kdrl:EGFP Spil:Ds Red zebrafish model. Furthermore, in a pilot assessment, loading and release of the sialyltransferase inhibitor (STI, 3Fax-Peracetyl Neu5Ac) using cGCM significantly reduced α-2,6 sialylation in 2D cultures of MDA-MB-231 cells, demonstrating the STI's intact functionality in inhibiting sialylation. By integrating bioinspired membranes with mechanically tunable gelatin-based carriers, our system demonstrates a multifunctional immune-mimicking platform with relevance to tissue engineering, tumour modelling, immune modulation, and drug delivery. These findings offer a promising foundation for future therapeutic strategies in cancer research and immuno-engineering.