pH-Insensitive Hydrogel Fiber Random Lasers

Overcoming the impact of pH on the performance of random lasers (RLs) has emerged as a significant challenge in its application for biomedical therapy. To tackle this issue, this paper proposes a pH-insensitive hydrogel fiber RLs. The RLs consists of Rhodamine B dye-doped p(acrylamide-co-acrylic acid, AM-co-AA) hydrogel as the fiber core and calcium alginate (Ca-alginate) hydrogel as the cladding, termed as p(AM-co-AA)/Ca-alginate hydrogel fiber RLs. The prepared RLs not only operate reliably at different pH levels but also allow for tuning of its emission wavelength by adjusting the temperature, ensuring the reliability and safety of photothermal therapy. Experimental results demonstrate that the threshold of p(AM-co-AA)/Ca-alginate hydrogel fiber RLs is only 0.23 mJ/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. Moreover, within the range of 20∼80 °C, the random laser emission wavelength can be tuned by controlling the temperature, with a maximum tunable range of 5.6 nm and good reversibility. Most importantly, the random laser intensity and wavelength of the p(AM-co-AA)/Ca-alginate hydrogel fiber RLs exhibit excellent stability when the pH value changes within the range of 3.5 to 9.5, indicating its exceptional ability to resist pH interference. We believe that the hydrogel fiber RLs proposed in this paper, leveraging the porous structure of hydrogel to reduce the laser threshold and employing the “core-cladding” structure to enhance stability, holds broad potential applications in the biomedical field.