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Optofluidic dye lasers integrated into microfluidic chips are promising miniature coherent light sources for biosensing. However, achieving the accurate and efficient tuning of lasers remains challenging. This study introduces a novel pneumatically tunable optofluidic distributed feedback (DFB) dye laser in a multilayer microfluidic chip. The dye laser device integrates microfluidic channels, grating structures, and vacuum chambers. A second-order DFB grating configuration is utilized to ensure single-mode lasing. The application of vacuum pressure to the chambers stretches the soft grating layer, enabling the sensitive tuning of the lasing wavelength at a high resolution of 0.25 nm within a 7.84 nm range. The precise control of pressure and laser tuning is achieved through an electronic regulator. Additionally, the integrated microfluidic channels and optimized waveguide structure facilitate efficient dye excitation, resulting in a low pump threshold of 164 nJ/pulse. This pneumatically tunable optofluidic DFB laser, with its high-resolution wavelength tuning range, offers new possibilities for the development of integrated portable devices for biosensing and spectroscopy. [ABSTRACT FROM AUTHOR]

3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGS) is a member of condensing enzymes that catalyze a Claisen-like condensation reaction.The tobacco (nicotiana tabacum) HMGS gene was firstly characterized using the rapid amplification of cDNA ends methods based on one tobacco EST. The full-length tobacco HMGS gene mRNA was 1,773bp containing a 1389 bp open reading frame, which encodes a protein of 462 amino acids. Sequence analysis revealed that the HMGS of tobacco shares high homology with the HMGS of nicotiana tomentosiformis (96%), nicotiana attenuata (95%), Nicotiana sylvestris (95%), nicotiana benthamiana(94%), solanum lycopersicum(94%), solanum tuberosum(93%) and withania somnifera(93%). Results also showed that tobacco HMGS gene has a closer genetic relationship with the HMGS gene of withania somnifera. Tissue expression profile analysis revealed that the tobacco HMGS gene was highly expressed in flower, but moderately expressed in leaf and stem, and weakly expressed in root. Our experiment established the foundation for further research on this tobacco gene.

Optofluidic dye lasers integrated into microfluidic chips are promising miniature coherent light sources for biosensing. However, achieving the accurate and efficient tuning of lasers remains challenging. This study introduces a novel pneumatically tunable optofluidic distributed feedback (DFB) dye laser in a multilayer microfluidic chip. The dye laser device integrates microfluidic channels, grating structures, and vacuum chambers. A second-order DFB grating configuration is utilized to ensure single-mode lasing. The application of vacuum pressure to the chambers stretches the soft grating layer, enabling the sensitive tuning of the lasing wavelength at a high resolution of 0.25 nm within a 7.84 nm range. The precise control of pressure and laser tuning is achieved through an electronic regulator. Additionally, the integrated microfluidic channels and optimized waveguide structure facilitate efficient dye excitation, resulting in a low pump threshold of 164 nJ/pulse. This pneumatically tunable optofluidic DFB laser, with its high-resolution wavelength tuning range, offers new possibilities for the development of integrated portable devices for biosensing and spectroscopy.