Abstract
Hydrogel fibers (HFs) have shown great potential for delivering light and sensing in vivo. However, HFs commonly suffer from high optical attenuation, which significantly affects their light-guiding efficiency and sensing performance. Here, we demonstrate a projection-suspended stereolithography (PSS) 3D printing method for fabricating low-loss HFs. Axially continuous and uniform HFs are produced via a light-curing area that floats on the precursor solution. Additionally, PSS improves the guiding efficiency of the HF by simultaneously regulating the fiber diameter, core–cladding structure, and refractive index. We obtained a loss of ≤0.15 dB/cm, which is better than that reported by previous studies. We also demonstrate that the fabricated HF provides light delivery and sensing capability in deep tissues, which will benefit the development of biomedicine and optogenetics. The PSS method heralds a novel fabrication for advanced waveguides.
Highlights
The delivery of light into biological tissue for sensing, imaging, and stimulation is a crucial aspect of applications in biosensing, photomedicine, and optogenetics.1–3 efficient delivery must overcome the challenges presented by the absorption and scattering characteristics of biological tissue.4 Optical fibers based on silica or inorganic plastic are popularly utilized for light penetration,5,6 but they are stiff and not biocompatible
In this Letter, we present the first demonstration of a projection-suspended stereolithography (PSS) 3D printing method to fabricate axially continuous and uniform Hydrogel fibers (HFs)
The slightly higher loss in tissue is presumably due to the contribution by the light leaked from the interface scattering
Summary
The delivery of light into biological tissue for sensing, imaging, and stimulation is a crucial aspect of applications in biosensing, photomedicine, and optogenetics.1–3 efficient delivery must overcome the challenges presented by the absorption and scattering characteristics of biological tissue.4 Optical fibers based on silica or inorganic plastic are popularly utilized for light penetration,5,6 but they are stiff and not biocompatible. It represents a potential solution to arbitrarily shape the hydrogel geometry and make high-resolution microstructures.22,23 the printing process solidifies the pattern layer-by-layer, resulting in axially discontinuous HFs, which makes the optical waveguide non-uniform, and leads to the nonlinear transmission of the axial optical field.24–26 the high optical loss remains a problem for HFs. In this Letter, we present the first demonstration of a projection-suspended stereolithography (PSS) 3D printing method to fabricate axially continuous and uniform HFs. We demonstrate how to improve the light-guiding efficiency by simultaneously optimizing the fiber diameter, core–cladding thickness, and RI distribution. PSS can fabricate HFs with submicrometersized to millimeter-sized diameters, offer flexibility in terms of the core–cladding structure, and modulate the RI by controlling the cross-linking intensity.
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