Self-assembled VEGF-R2 targeting DNA aptamer-collagen fibers stimulate an angiogenic-like endothelial cell phenotype

Exploring the Fibrous Nature of Single-Stranded DNA-Collagen Complexes: Nanostructural Observations and Physicochemical Insights

Nucleic acid-collagen complexes (NACCs) are a self-assembled biomimetic fibrillary platform arising from the spontaneous complexation of single-stranded DNA (ssDNA) oligonucleotides and collagen. NACCs merge the extracellular matrix functionality of collagen with the tunable bioactivity of ssDNA as aptamers for broad biomedical applications. We hypothesize that NACCs offer a hierarchical architecture across multiple length scales that significantly varies compared to native collagen. We investigate this using atomic force microscopy and electron microscopy (transmission electron microscopy and cryogenic electron microscopy). Results demonstrate key topographical differences induced by adding ssDNA oligonucleotides to collagen type I. NACCs form a dense network of intertwined collagen fiber bundles in the microscale and nanoscale while retaining their characteristic D-band periodicities (∼67 nm). Additionally, our exploration of thermodynamic parameters governing the interaction indicates an entropically favorable NACC formation driven by ssDNA. Thermal analysis demonstrates the preservation of collagen's triple helical domains and a more stabilized polypeptide structure at higher temperatures than native collagen. These findings offer important insights into our understanding of the ssDNA-induced complexation of collagen toward the further establishment of structure-property relationships in NACCs and their future development into practical biomaterials. They also provide pathways for manipulating and enhancing collagenous matrices' properties without requiring complex chemical modifications or fabrication procedures.

Application of aptamers in regenerative medicine

Regenerative medicine is a discipline that studies how to use biological and engineering principles and operation methods to repair and regenerate damaged tissues and organs. Until now, regenerative medicine has focused mainly on the in-depth study of the pathological mechanism of diseases, the further development and application of new drugs, and tissue engineering technology strategies. The emergence of aptamers has supplemented the development methods and types of new drugs and enriched the application elements of tissue engineering technology, injecting new vitality into regenerative medicine. The role and application status of aptamers screened in recent years in various tissue regeneration and repair are reviewed, and the prospects and challenges of aptamer technology are discussed, providing a basis for the design and application of aptamers in long-term transformation.