High-risk human papillomavirus (hrHPV) is the primary cause of nearly all cervical cancers and contributes to a subset of vulva, anal, vaginal, penile, and oropharyngeal malignancies [1], [2]. Molecular detection of hrHPV forms the foundation of cervical screening programs [3]. The most common specimen type is liquid-based cytology (LBC) collected in PreservCyt®, a methanol-buffered preservative that stabilizes cellular and viral material but also introduces potent polymerase chain reaction (PCR) inhibition, necessitating nucleic-acid extraction before amplification [4], [5], [6]. Extraction increases cost, labor, and reliance on consumables, limiting scalability in both high-throughput laboratories and resource-limited settings [7]. Although extraction-free, or direct-to-PCR, approaches have shown recent success for pathogen diagnostics [8], [9], [10], PreservCyt® poses two distinct barriers to such methods: the high methanol concentration inhibits PCR directly, and the structural resilience of the HPV capsid further impedes access to viral DNA without prior extraction. Together, these factors make direct-to-PCR amplification from PreservCyt® specimens particularly challenging [11], [12]1.

We hypothesized that targeted destabilization of the HPV capsid could increase genome accessibility and reduce susceptibility of downstream amplification to matrix-borne inhibitors. To achieve this, we developed a rationally designed antiviral peptide (Molecular Diagnostic Peptide-1 [MDP-1]), engineered to bind the HPV L1 major capsid protein with high affinity. Unlike cationic antimicrobial peptides (AMPs), which have been widely studied for their ability to disrupt bacterial membranes (e.g., MRSA and VRE), MDP-1 represents a new application of peptide engineering in viral applications. Prior AMP work has focused on therapeutic membrane lysis, whereas MDP-1 was designed to interfere with L1–L1 interactions and promote partial capsid disassembly, thereby enhancing nucleic-acid release for amplification. This shift from antimicrobial killing to diagnostic facilitation establishes MDP-1 as the prototype of a new class of “capsid-targeted diagnostic enhancers,” distinct from conventional AMPs, and capable of enabling extraction-free qPCR detection of hrHPV directly from PreservCyt® specimens