Ultrafast Photonic PCR with All-Solution-Processed Ti₃C₂T_x-Based Perfect Absorbers

Polymerase chain reaction (PCR) is a critical tool for nucleic acid amplification in molecular diagnosis and genetic analysis. Point-of-care (POC) devices are essential for controlling the spread of infectious diseases, but developing cost-effective chip-based PCR systems remains a challenge. This study introduces a photonic PCR chip featuring a perfect metamaterial absorber made of Ti₃C₂T_x MXene, silicon dioxide (SiO₂), and gold nanoparticles (GNP) in a metal-insulator-metal (MIM) configuration. Fabricated via a solution-processing approach, the absorber demonstrates 98% light absorption without the need for expensive lithographic methods. Utilizing a 940 nm infrared (IR) LED, the chip achieves efficient photothermal effects with heating rates of ≈8.3 °C s⁻¹ and cooling rates of ≈7.2 °C s⁻¹ during 30 cycles of λ-DNA and SARS-CoV-2 amplification, transitioning from 65 °C to 95 °C. The low cost and high efficiency of the MXene-based metamaterial absorbers highlight their potential as key components for ultrafast, energy-efficient molecular diagnostic chips suitable for on-site applications.