Engineering Polysaccharide‐Based Hydrogel Photonic Constructs: From Multiscale Detection to the Biofabrication of Living Optical Fibers

Abstract

Solid‐state optics has been the pillar of modern digital age. Integrating soft hydrogel materials with micro/nanooptics could expand the horizons of photonics for bioengineering. Here, wet‐spun multilayer hydrogel fibers are engineered through ionic‐crosslinked natural polysaccharides that serve as multifunctional platforms. The resulting flexible hydrogel structure and reversible crosslinking provide tunable design properties such as adjustable refractive index and fusion splicing. Modulation of the optical readout via physical stimuli, including shape, compression, and multiple optical inputs/outputs is demonstrated. The unique permeability of the hydrogels is also combined with plasmonic nanoparticles for molecular detection of SARS‐CoV‐2 in fiber‐coupled biomedical swabs. A tricoaxial 3D printing nozzle is then employed for the continuous fabrication of living optical fibers. Light interaction with living cells enables the quantification and digitalization of complex biological phenomena such as 3D cancer progression and drug susceptibility. These fibers pave the way for advances in biomaterial‐based photonics and biosensing platforms.

Advanced Point‐of‐Care Testing Technologies for Human Acute Respiratory Virus Detection

“…Centrifugal microfluidic nucleic acid assay 10 copies µL −1 10 5 -10 1 copies µL −1 10 5 -10 1 copies µL −1 10 7 -10 1 copies µL −1 10 7 -10 1 copies µL −1 10 7 -10 1 copies µL −1 10 7 -10 1 copies µL −1 10 7 -10 [100][101][102] Optical POCTs for specific recognition of RVs depend on signal conversion to an easily measurable optical signal through physical methods, e.g., colorimetry [103,104] or fluorescence, [105] hydrogel photonic construct, [106] and biochemical approaches, e.g., enzyme activation, surface-enhanced Raman scattering (SERS), [107] or surface plasmon resonance (SPR). [108] The SERS signal comes from Raman scattering due to RV recognition by Abs or aptamer molecules adsorbed on the surfaces of nanostructures, while the SPR signal depends on the refractive index of Au or Ag detection surface before and after the recognition of RV via Abs or aptamers.…”

Pushing the Natural Frontier: Progress on the Integration of Biomaterial Cues toward Combinatorial Biofabrication and Tissue Engineering

“…In 3D gradient fabrication, microfluidics has proven to be a very powerful tool for the creation of screening libraries. Microfluidic-driven hydrogel manipulation can very efficiently create droplets, [248] 3D microfibers, [249,250] or combinations thereof. [251] Typically, microfluidic-driven biofabrication is extremely fast and capable of introducing 3D microarchitectures that can recapitulate the organization of living tissues, [205,252] as well as establish 3D gradients by controlled hydrogel precursor mixing, followed by deposition onto chips, [253] or spinning into 3D fibers.…”

Investigation of coupling loss caused by misalignment in optical fiber

“…Optical fiber couplers can interface at least one fiber to permit the transmission of light waves in different paths. Inputs from multiple sources can be combined into a single output [1]. Fiber optic couplers are either active or passive.…”