Special Issue "Advances in Diagnostics: Applications of Nucleic Acids and Their Analogs"

Nucleic acids and their synthetic analogs have driven modern diagnostics of versatile platforms capable of detecting disease signatures with molecular precision [1]. Classical hybridization assays based on sequence complementarity have been strengthened by peptide nucleic acids (PNAs) and locked nucleic acids (LNAs), which provide higher affinity, improved mismatch discrimination, and resistance to nuclease degradation, enabling sensitive detection in complex matrices [2,3]. Conformation-responsive elements such as aptamers further expand capabilities: they offer antibody-like affinity with superior thermal/chemical stability and batch consistency, making them suitable for portable and point-of-care devices [4,5,6]. In parallel, CRISPR-based detectors exploit programmable recognition and collateral nuclease activity (e.g., Cas13, Cas12) to achieve isothermal signal amplification and very low limits of detection in platforms such as SHERLOCK and DETECTR [7,8]. Finally, diagnostic readouts now extend beyond sequence to epitranscriptomic and epigenetic marks: RNA modifications (e.g., m6A, m5C) and DNA hydroxymethylation provide insight into cell state and disease. These marks are becoming increasingly measurable owing to advances in selective chemistry, enzymatic labelling, and sequencing/nanopore-based detection methods [9,10,11].