Vibrational strong coupling (VSC) between molecular transitions and photonic structures can be used to tune the reactivity of molecules, and hybrid polariton states have been employed to modify the energy landscape of molecular systems in an optical cavity. To investigate how to modulate life reactions with VSC, herein we selected an in vitro model bioreaction, DNA replication, i.e., recombinase polymerase amplification (RPA), to couple with the typical Fabry–Pérot (FP) cavity mode. Known as an isothermal enzymatic reaction, RPA well satisfies the VSC study within FP cavities. Through tuning the resonance coupling strength between water molecules and FP cavity modes, we can regulate the efficiency of RPA as the cavity modes change from 3100 to 3550 cm–1. The results showed that O–H-based VSC can significantly inhibit the efficiency of RPA by ∼58%. Due to the key role of water in life, O–H stretching vibrational coupling with photonic structures could be a novel tool to regulate life in turn.

Photothermal therapy (PTT) is regarded as one of the potential techniques to replace surgery in the treatment of tumors. Polyaniline (PANI) shows better biocompatibility than inorganic reagents, which has been widely used in tumor photoacoustic (PA) imaging and PTT. However, the poor water solubility and nonspecific aggregation of PANI nanoparticles severely restricted their biomedical application. In addition, it is difficult to control the photothermal effect just on cancer cells. Herein, we develop tumor pH-responsive PANI-Gel/Cu assemblies, which can achieve targeted and precise ablation of tumors. Due to the high hydrophilicity of gelatin, the PANI-Gel/Cu assemblies show excellent dispersion in physiological solutions and long-term stability. By taking advantage of the self-doping effect between the carboxyl groups in gelatin and the imine part of the PANI skeleton, the photothermal characteristics of PANI-Gel/Cu assemblies can be promoted effectively by the acid tumor microenvironment, and the PA imaging of PANI-Gel/Cu assemblies can also be activated by tumor pH. Consequently, both the PTT enhancement and PA signal amplification can be triggered under a tumor microenvironment, and PANI-Gel/Cu assemblies can be targeted to cancer cells with the RGD sequences in their gelatin skeleton. In vivo imaging-guided PTT to A549 cancer shows precise treatment with little harm to normal cells, and PANI-Gel/Cu assemblies can disassemble into tiny particles (<15 nm) under laser irradiation. This work overcomes the intrinsic limitation of PANI materials, i.e., poor water solubility and nonspecific aggregation, meanwhile providing a pH-active PANI-based platform for precise and effective ablation of cancer.

Polaritonic chemistry has become an important research field, since vibrational strong coupling (VSC) between molecular transitions and photonic structures was discovered to alter the energy landscape of molecules, through the creation of hybrid states in an optical cavity resonant to a molecular absorption band. ATP hydrolysis is an essential reaction in all known forms of life and have fundamental roles in energy conservation, active transport and pH homeostasis. Herein, using a Fabry‐Pérot (FP) cavity filled with the ATP hydrolysis solution, we measured the ATP hydrolysis efficiency in both strong and weak coupling modes and investigated the VSC effect on the catalytic activity of ATPase at the stretching vibration band of water. We observed an approximately 10‐fold increase of the apparent hydrolysis rate when coupling with the water stretching vibration. This work demonstrates the potential of employing VSC to precisely interfere water‐based biochemical reactions.