biostudies-literatureLi Hthe Guangdong Basic and Applied Basic Research FoundationNational Natural Science Foundation of China73https://www.ebi.ac.uk/biostudies/studies/S-EPMC12044087biostudies-literatureUnknown20(1)Optical manipulation and detection of single molecules, such as biomolecules and bacterial viruses, are crucial in single-molecule mechanics and biosensing. The interaction between light and individual molecules is weak due to the size of biomolecules (≤ 10 nm) being significantly smaller than the wavelength (λ) of light. This limitation results in a reduced optical gradient force and diminished detection sensitivity of light on biomolecules. To overcome this challenge, we propose a single-molecule trapping and sensing method that utilizes whisper-gallery mode (WGM) coupled photonic nanojets (PNJs). Our theoretical analysis demonstrates that a focused beam with a waist radius of λ/6 can be generated by WGM-coupled PNJs. By harnessing this sub-diffraction-limit focused beam, we create a staDiscover nanoSingle-molecule manipulation and detection by WGM-coupled photonic nanojets.PMC120440872023A1515030143624225051247443162305132Li HLi YHe TZhang YWu TGong ZfalseSingle-molecule manipulation and detection by WGM-coupled photonic nanojets.Optical manipulation and detection of single molecules, such as biomolecules and bacterial viruses, are crucial in single-molecule mechanics and biosensing. The interaction between light and individual molecules is weak due to the size of biomolecules (≤ 10 nm) being significantly smaller than the wavelength (λ) of light. This limitation results in a reduced optical gradient force and diminished detection sensitivity of light on biomolecules. To overcome this challenge, we propose a single-molecule trapping and sensing method that utilizes whisper-gallery mode (WGM) coupled photonic nanojets (PNJs). Our theoretical analysis demonstrates that a focused beam with a waist radius of λ/6 can be generated by WGM-coupled PNJs. By harnessing this sub-diffraction-limit focused beam, we create a sta2025-01-01T00:00:00Z2025 Apr2025-07-10T03:08:39.88Z2025-07-10T03:08:39.88ZS-EPMC120440874030493310.1186/s11671-025-04253-3