Spatial control of PEG-lipid interfaces at cell surface enables on-demand adhesion and enzymatic detachment of suspension cells

Abstract

Suspension cells are widely used in biomedical research and cell-based therapies; however, their lack of stable adhesion to substrates limits their efficient handling, including gene delivery and downstream processing. Although surface engineering approaches have been studied to induce cell adhesion, precise control over attachment and detachment, comparable to that of adherent cells, remains challenging. Here, we report a strategy to control cell adhesion and detachment using enzyme-responsive trans-activator of transcription peptide–poly(ethylene glycol)-lipid (Tat-PEG-lipid) conjugates and non-functional poly(ethylene glycol)-lipids (PEG-lipid). A collagenase-cleavable peptide sequence was inserted between the Tat peptide and the PEG chain, yielding Tat-Col-PEG-lipid constructs with PEG molecular weights of 20 and 40 kDa. These conjugates were incorporated into the cell membranes of CCRF-CEM cells, a human T-lymphoblastoid cell line, to induce adhesion via the Tat peptide. To regulate the interfacial structure, Tat-Col-PEG-lipid was co-assembled with a non-functional PEG(5k)-lipid, enabling precise control over the surface density to improve collagenase access. We demonstrated that the mixed PEG-lipid modification allows robust cell adhesion to substrates while enabling efficient detachment upon collagenase treatment. Notably, the use of Tat-Col-PEG-lipids with longer PEG chains (40 kDa) significantly improved the adhesion efficiency, enzymatic detachment, and cell viability compared to shorter PEG chains. Optimal mixing ratios of Tat-Col-PEG(40k)-lipids and PEG(5k)-lipids resulted in stable attachment and rapid collagenase-triggered release across different substrates, planar surfaces, and fibrous scaffolds. This hierarchical PEG-lipid modification approach provides a versatile and minimally invasive platform for the transient manipulation of suspended cells, with potential applications in gene delivery, cell processing, and regenerative medicine.