This infographic presents a horizontal timeline illustrating scientific milestones in DNA nanotechnology and nucleic acid hydrogels (NAHs) from 1950 to the 2020s. The timeline is visually anchored by a blue double-helix DNA strand, with decade markers serving as nodes for historical breakthroughs. Key historical points include the 1953 proposal of the double-helix structure by Watson and Crick, the discovery of triple-helix structures in 1957 and 1963, and the enzymatic activity of ribozymes (1978/1981). Transitioning into functional DNA nanotechnology, the timeline highlights the 1982 foundation of the field by Nadrian Seeman, the birth of aptamers and SELEX in 1990, and the construction of peptide nucleic acids (1991). Significant developments in hydrogel science are featured, specifically the first synthesis of a DNA-contained polymer hydrogel in 1996 by Nagahara and Matsuda, and the 2006 assembly of the first all-DNA hydrogel by Dan Luo et al. The diagram maps the progression from basic molecular biology to the engineering of smart, functionalized biomaterials for medical and diagnostic applications.

This medical illustration represents a molecular model of a deoxyribonucleic acid (DNA) double helix, categorized under genetics and molecular biology. The image features a stylized, high-contrast visualization where one phosphodiester backbone is depicted with a solid, light blue, segmented geometric structure, and the antiparallel strand is rendered as a nebulous, particulate cloud in shades of purple and orange. Horizontal rungs, representing nitrogenous base pairs (adenine-thymine and cytosine-guanine), connect the two strands across the central axis. The use of particulate textures and glowing elements suggests concepts of genetic instability, DNA damage, or the dynamic nature of replication and transcription. This artistic rendering is suitable for educational use in explaining basic DNA architecture, genomic medicine, or molecular pathology at an introductory to intermediate level.

A comparison chart consisting of four vertically stacked subplots representing molecular dynamics simulation results for DNA duplexes using different force fields: CHARMM27, CHARMM36, AMBER_bsc_0, and AMBER_bsc_1. Each plot displays the Root Mean Square Fluctuation (RMSF) Ratio between Hoogsteen (HG) and Watson-Crick (WC) base pairing forms (y-axis) plotted against the Heavy Atom Index (x-axis, 0–700). Vertical black lines delineate specific base pairs (C1 through G24), with A16 and T9 highlighted as primary areas of interest. The data is shown as green line graphs with light green shading indicating 95% confidence intervals from five 50 ns trajectory segments; a horizontal blue line at y=1.0 serves as a baseline for equal fluctuation between HG and WC forms. The diagrams illustrate biophysical variations in DNA flexibility: CHARMM models show a decrease in the HG/WC ratio at A16 (increased HG fluctuations), while AMBER models show an increase at A16 (increased WC fluctuations), highlighting how different computational force fields model the entropic impact of Hoogsteen base pairing on B-DNA structural stability.

This diagnostic image displays four 1H-NMR (Proton Nuclear Magnetic Resonance) spectra, labeled (a) through (d), illustrating the imino proton region (10.5–15.5 ppm) of DNA oligonucleotides from the N-myc gene. The spectra demonstrate how biochemical conditions (pH and KCl concentration) influence DNA secondary structures. Spectra (a), (c), and (d) show prominent, well-resolved peaks between 12.5 and 14.0 ppm, which are characteristic fingerprints for Watson–Crick base-pairing in double-stranded helical structures. In contrast, spectrum (b), representing conditions of 100 mM KCl and pH 5.0, shows a marked reduction in Watson–Crick signals and the appearance of broad peaks between 10.5 and 12.0 ppm. Additionally, spectrum (b) displays a unique signal near 15.5 ppm, indicating the formation of C+ · C base pairs characteristic of i-motif structures. These visual variations illustrate the structural transition from a canonical duplex to non-canonical G-quadruplex and i-motif configurations under acidic and salt-stabilized conditions, making this a critical reference for molecular genetics and structural biology education.