Synthetic DNA for Cell Surface Engineering: Experimental Comparison between Click Conjugation and Lipid Insertion in Terms of Cell Viability, Engineering Efficiency, and Displaying Stability

Advancements in adoptive CAR immune cell immunotherapy synergistically combined with multimodal approaches for tumor treatment

Adoptive immunotherapy, notably involving chimeric antigen receptor (CAR)-T cells, has obtained Food and Drug Administration (FDA) approval as a treatment for various hematological malignancies, demonstrating promising preclinical efficacy against cancers. However, the intricate and resource-intensive autologous cell processing, encompassing collection, expansion, engineering, isolation, and administration, hamper the efficacy of this therapeutic modality. Furthermore, conventional CAR T therapy is presently confined to addressing solid tumors due to impediments posed by physical barriers, the potential for cytokine release syndrome, and cellular exhaustion induced by the immunosuppressive and heterogeneous tumor microenvironment. Consequently, a strategic integration of adoptive immunotherapy with synergistic multimodal treatments, such as chemotherapy, radiotherapy, and vaccine therapy etc., emerges as a pivotal approach to surmount these inherent challenges. This collaborative strategy holds the key to addressing the limitations delineated above, thereby facilitating the realization of more precise personalized therapies characterized by heightened therapeutic efficacy. Such synergistic strategy not only serves to mitigate the constraints associated with adoptive immunotherapy but also fosters enhanced clinical applicability, thereby advancing the frontiers of therapeutic precision and effectiveness.

Display of Polyvalent Hybrid Antibodies on the Cell Surface for Enhanced Cell Recognition

Cell surface engineering with exogeneous receptors holds great promise for various applications. However, current biological methods face problems with safety, antigen escape, and receptor stoichiometry. The purpose of this study is to develop a biochemical method for displaying polyvalent antibodies (PAbs) on the cell surface. The PAbs are synthesized through the self-assembly of DNA-Ab conjugates under physiological conditions without the involvement of any factors harsh to cells. The data show that PAb-functionalized cells can recognize target cells much more effectively than monovalent controls. Moreover, dual Ab incorporation into the same PAb with a defined stoichiometric ratio leads to the formation of a polyvalent hybrid Ab (DPAb). DPAb-functionalized cells can effectively recognize target cell models with antigen escape, which cannot be achieved by PAbs with one type of Ab. Therefore, this work presents a novel biochemical method for Ab display on the cell surface for enhanced cell recognition.

Integrating Metabolic Oligosaccharide Engineering and SPAAC Click Chemistry for Constructing Fibrinolytic Cell Surfaces

To effectively solve the problem of significant loss of transplanted cells caused by thrombosis during cell transplantation, this study simulates the human fibrinolytic system and combines metabolic oligosaccharide engineering with strain-promoted azide-alkyne cycloaddition (SPAAC) click chemistry to construct a cell surface with fibrinolytic activity. First, a copolymer (POL) of oligoethylene glycol methacrylate (OEGMA) and 6-amino-2-(2-methylamido)hexanoic acid (Lys) was synthesized by reversible addition-fragmentation chain transfer (RAFT) copolymerization, and the dibenzocyclooctyne (DBCO) functional group was introduced into the side chain of the copolymer through an active ester reaction, resulting in a functionalized copolymer DBCO-PEG4-POL with ε-lysine ligands. Then, azide functional groups were introduced onto the surface of HeLa model cells through metabolic oligosaccharide engineering, and DBCO-PEG4-POL was further specifically modified onto the surface of HeLa cells via the SPAAC "click" reaction. In vitro investigations revealed that compared with unmodified HeLa cells, modified cells not only resist the adsorption of nonspecific proteins such as fibrinogen and human serum albumin but also selectively bind to plasminogen in plasma while maintaining good cell viability and proliferative activity. More importantly, upon the activation of adsorbed plasminogen into plasmin, the modified cells exhibited remarkable fibrinolytic activity and were capable of promptly dissolving the primary thrombus formed on their surfaces. This research not only provides a novel approach for constructing transplantable cells with fibrinolytic activity but also offers a new perspective for effectively addressing the significant loss of transplanted cells caused by thrombosis.

Biomimetic Bacterial Capsule for Enhanced Aptamer Display and Cell Recognition

Great effort has been made to encapsulate or coat living mammalian cells for a variety of applications ranging from diabetes treatment to three-dimensional printing. However, no study has reported the synthesis of a biomimetic bacterial capsule to display high-affinity aptamers on the cell surface for enhanced cell recognition. Therefore, we synthesized an ultrathin alginate-polylysine coating to display aptamers on the surface of living cells with natural killer (NK) cells as a model. The results show that this coating-mediated aptamer display is more stable than direct cholesterol insertion into the lipid bilayer. The half-life of the aptamer on the cell surface can be increased from less than 1.5 to over 20 h. NK cells coated with the biomimetic bacterial capsule exhibit a high efficiency in recognizing and killing target cells. Therefore, this work has demonstrated a promising cell coating method for the display of aptamers for enhanced cell recognition.

Engineering Biomimetic Microenvironment for Organoid

Organoid is an emerging frontier technology in the field of life science, in which pluripotent stem cells or tissue-derived differentiated/progenitor cells form 3D structures according to their multi-directional differentiation potential and self-assembly ability. Nowadays, although various types of organoids are widely investigated, their construction is still complicated in operation, uncertain in yield, and poor in reproducibility for the structure and function of native organs. Constructing a biomimetic microenvironment for stem cell proliferation and differentiation in vitro is recognized as a key to driving this field. This review reviews the recent development of engineered biomimetic microenvironments for organoids. First, the composition of the matrix for organoid culture is summarized. Then, strategies for engineering the microenvironment from biophysical, biochemical, and cellular perspectives are discussed in detail. Subsequently, the newly developed monitoring technologies are also reviewed. Finally, a brief conclusion and outlook are presented for the inspiration of future research.

Cell Surface Engineering Tools for Programming Living Assemblies

Breakthroughs in precision cell surface engineering tools are supporting the rapid development of programmable living assemblies with valuable features for tackling complex biological problems. Herein, the authors overview the most recent technological advances in chemically- and biologically-driven toolboxes for engineering mammalian cell surfaces and triggering their assembly into living architectures. A particular focus is given to surface engineering technologies for enabling biomimetic cell-cell social interactions and multicellular cell-sorting events. Further advancements in cell surface modification technologies may expand the currently available bioengineering toolset and unlock a new generation of personalized cell therapeutics with clinically relevant biofunctionalities. The combination of state-of-the-art cell surface modifications with advanced biofabrication technologies is envisioned to contribute toward generating living materials with increasing tissue/organ-mimetic bioactivities and therapeutic potential.

Advancing cell surface modification in mammalian cells with synthetic molecules

Biological cells, being the fundamental entities of life, are widely acknowledged as intricate living machines. The manipulation of cell surfaces has emerged as a progressively significant domain of investigation and advancement in recent times. Particularly, the alteration of cell surfaces using meticulously crafted and thoroughly characterized synthesized molecules has proven to be an efficacious means of introducing innovative functionalities or manipulating cells. Within this realm, a diverse array of elegant and robust strategies have been recently devised, including the bioorthogonal strategy, which enables selective modification. This review offers a comprehensive survey of recent advancements in the modification of mammalian cell surfaces through the use of synthetic molecules. It explores a range of strategies, encompassing chemical covalent modifications, physical alterations, and bioorthogonal approaches. The review concludes by addressing the present challenges and potential future opportunities in this rapidly expanding field.

Deoxyribonucleic Acid-Based Polyvalent Ligand-Receptor Binding for Engineering the Cell Surface with Nanoparticles

Tethering nanoparticles (NPs) onto the cell surface is critical to cellular hitchhiking applications, such as targeted NP delivery and enhanced cell therapy. While numerous methods have been developed to achieve NP attachment onto the cell membrane, they often face limitations such as the use of complicated cell surface modifications or low-efficiency NP attachment. The purpose of this work was to explore a DNA-based synthetic ligand-receptor pair for NP attachment to the surface of live cells. Polyvalent ligand mimics were used to functionalize NPs, while the cell membrane was functionalized with DNA-based cell receptor mimics. Base pair-directed polyvalent hybridization allowed the NPs to bind to the cells quickly and efficiently. Notably, the process of attaching NPs to cells did not require sophisticated chemical conjugation on the cell membrane or involve any cytotoxic cationic polymers. Therefore, DNA-based polyvalent ligand-receptor binding is promising to various applications ranging from cell surface engineering to NP delivery.

Effects of Various Cell Surface Engineering Reactions on the Biological Behavior of Mammalian Cells

Cell surface engineering technologies can regulate cell function and behavior by modifying the cell surface. Previous studies have mainly focused on investigating the effects of cell surface engineering reactions and materials on cell activity. However, they do not comprehensively analyze other cellular processes. This study exploits covalent bonding, hydrophobic interactions, and electrostatic interactions to modify the macromolecules succinimide ester-methoxy polyethylene glycol (NHS-mPEG), distearoyl phosphoethanolamine-methoxy polyethylene glycol (DSPE-mPEG), and poly-L-lysine (PLL), respectively, on the cell surface. This work systematically investigates the effects of the three surface engineering reactions on the behavior of human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts, including viability, growth, proliferation, cell cycle, adhesion, and migration. The results reveals that the PLL modification method notably affects cell viability and G2/M arrest and has a short modification duration. However, the DSPE-mPEG and NHS-mPEG modification methods have little effect on cell viability and proliferation but have a prolonged modification duration. Moreover, the DSPE-mPEG modification method highly affects cell adherence. Further, the NHS-mPEG modification method can significantly improve the migration ability of HUVECs by reducing the area of focal adhesions. The findings of this study will contribute to the application of cell surface engineering technology in the biomedical field.