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. 2026 Oct 19;21:604909. doi: 10.2147/IJN.S604909

Figure 2.

Two part schematic, Basic Structure of SNAs and Classification by core with three core types. Image A depicts a schematic with a large spherical particle and multiple strands, including an enlarged strand with three segments labeled: Attachment group (SH, N subscript 3, NH subscript 2, COO, Tocopherol), Spacer (5-10 nt, PEG, poly T, poly A) and Recognition sequence (ASOs, siRNAs, miRNAs, mRNAs, pDNAs). Below is Image B, showing a classification layout with three columns: I. Inorganic core SNAs (AuNP, Ag/Pt, Fe subscript 3O subscript 4, Silica), II. Organic core SNAs (Liposomal, Polymeric, Protein) and III. Core-free SNAs (Hollow, Core-free).

Structural organization, core-based classification, and representative architectures of SNAs. (A) Basic SNA, consisting of a multifunctional core surrounded by a dense, radially oriented oligonucleotide shell with an attachment group, a spacer region, and a recognition sequence. (B) Classification of SNAs according to the nature or absence of the core, including inorganic-core SNAs, organic-core SNAs, and core-free SNAs. Selected SNA structures were drawn with assistance from ChatGPT (GPT-4o, OpenAI) and subsequently edited and assembled by the authors.