A recent article in Scientific Reports investigated the optical properties of surfactant-free deoxyribonucleic acid (SF-DNA) solid films, focusing on their dual-band transparency in the near-infrared (IR) and terahertz (THz) regions.
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The study explored the potential of these optical characteristics for photonics applications, including sensing and imaging technologies, emphasizing the biocompatibility and distinct optical traits of SF-DNA films. The findings highlight the potential of DNA-based materials for advancements in optoelectronic devices.
Advancements in DNA-Based Technologies
Watson and Crick's discovery of the DNA double-helix structure transformed molecular biology and opened avenues for its use in optoelectronics. Thin solid films derived from DNA have shown potential in applications such as optical amplifiers, organic light-emitting diodes (OLEDs), and sensors.
However, many current applications rely on hybrid DNA structures combined with polymers or inorganic materials, limiting their performance to infrared and visible light and reducing biocompatibility due to surfactants.
In contrast, surfactant-free DNA (SF-DNA) films prepared from aqueous solutions present a biocompatible alternative. This study investigates the optical properties of SF-DNA films across the ultraviolet (UV), visible, IR, and THz) spectral ranges.
Methodologies
SF-DNA thin solid films were fabricated using spin-coating and drop-casting techniques with aqueous precursors. These films were categorized into nanometer-scale (40-200 nm) and micrometer-scale (1-300 μm) thicknesses. The focus was to examine the transmission properties of these films over a wide spectral range, from UV to THz, while also measuring their refractive index and birefringence.
To verify DNA purity, absorbance measurements at 230, 260, and 280 nm were conducted to confirm low levels of protein and humic acid contamination. The spin-coating process included oxygen plasma treatment of substrates to enhance wettability, followed by the application of the DNA solution and spinning to produce films with uniform thickness. Freestanding films were also created using the drop-casting method and peeled off for analysis.
Key Findings and Insights
SF-DNA films demonstrated dual-band transparency in the near-infrared range (1270–1870 nm) and the THz range (0.22–0.64 THz), indicating their potential as optical components such as prisms, lenses, and waveguides for IR-THz sensing and imaging technologies. The films achieved over 80% transmittance in key spectral ranges, highlighting their suitability for optical applications.
Refractive index measurements showed significant birefringence, a property essential for polarization control in optical systems. Birefringence increased with film thickness, stabilizing at approximately 100 nm, suggesting improved alignment of DNA helices with thickness.
The authors also introduced a method for fabricating cylindrical DNA waveguides by placing SF-DNA between optical fiber facets. These waveguides exhibited low propagation losses (6.7–10.5 dB/mm) and enhanced light coupling between fibers, presenting opportunities for biochemical sensing and photonic device integration.
Applications in Optoelectronics
Due to its dual-band transparency in the IR and THz ranges, SF-DNA shows promise for applications in telecommunications, medical diagnostics, and environmental monitoring. Its biocompatibility and flexibility make it suitable for fabricating optical components for biosensing technologies, enabling real-time monitoring of biological and chemical processes.
The development of DNA-based waveguides expands their potential, offering efficient sensing capabilities in challenging environments. These sensors can detect temperature variations, humidity changes, and biochemical interactions, demonstrating the versatility of DNA for applications beyond traditional biotechnological uses.
Future Directions
This study advanced the understanding of SF-DNA films in optoelectronic technologies, highlighting their dual-band transparency and low propagation loss as alternatives to traditional optical materials. Future research may focus on refining fabrication methods, tailoring films for specific applications, and assessing their performance in real-world conditions.
The findings contribute to the development of DNA-based materials, setting the foundation for photonic device innovation. Integrating DNA components into existing systems has the potential to enhance optoelectronics, enabling efficient and sustainable technological advancements.
Journal Reference
Jeong, H., et al. (2024). Dual-band transparency over near-IR and THz in surfactant-free DNA solid film. Sci Rep. 10.1038/s41598-024-77968-5, https://www.nature.com/articles/s41598-024-77968-5
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