High-Resolution Patterning of Hydrogel Sensing Motifs within Fibrous Substrates for Sensitive and Multiplexed Detection of Biomarkers

Abstract

There has been an increasing and urgent demand to develop nucleic acid bioassays which not only offer high analytical performance but which are also amenable with point-of-care testing. Hydrogels present a versatile class of materials with biocompatible antifouling properties and the ability to be engineered for a range of advanced sensing applications. Fibrous substrates like nitrocellulose offer low-cost and durable platforms to run complex bioassays while enabling portability and ease of handling. We demonstrate herein the ability to synergistically combine these two materials into a portable biosensing platform by leveraging projection lithography. We demonstrate the direct polymerization of hydrogel sensing motifs within a range of fibrous substrates with precise control over their shape, size, location, and functionality. Spatial encoding of the hydrogel motifs enables the multiplex detection of multiple biomarkers on the same test. As a proof-of-concept, we apply the platform to the detection of microRNA, an emerging class of circulating biomarkers with promising potential for early diagnosis and monitoring of cancer. The assay offers a large dynamic range (over three orders of magnitude), high sensitivity (limit of detection of 2.5 amol), as well as versatility and ease of handling. Finally, the bioassay is validated using real biological samples, namely, total RNA extracted from the sera of late-stage breast cancer patients, demonstrating its utility and compatibility with clinical biosensing applications.

Hydrogel‐based composites: Unlimited platforms for biosensors and diagnostics

“…Some recent investigations have demonstrated the integration of different functions in individual hydrogel‐based devices. [ 329–332 ] For example, Chekini et al. constructed a wound dressing based on CD–cellulose–GE hydrogels that possess not only the antibacterial ability but also the sensing ability toward Fe 3+ ions based on the charge transfer‐induced fluorescent quenching (Figure 12A).…”

Hydrogel Nanoarchitectonics: An Evolving Paradigm for Ultrasensitive Biosensing

“…[ 237 ] Hydrogel sensing motif has been patterned on a fibrous substrate for miRNA detection. [ 238 ] Similarly, a 3D hydrogel‐based on chitosan and carbon dots (CDs) has been developed for breast cancer detection using a miRNA‐21 biomarker. [ 239 ] In their work, the carbon dot‐chitosan nanocomposite hydrogel was prepared as a biosensor scaffold.…”

Green Hydrogel Synthesis: Emphasis on Proteomics and Polymer Particle-Protein Interaction

“…In general, lower crosslinking density biases the hydrogel to the sol state—greater hydrophilicity, degree of swelling, and larger pore sizes—whereas higher crosslinking density biases the hydrogel to the gel state—greater hydrophobicity, more structurally collapsed, and greater mechanical strength [ 120 , 126 , 131 , 132 , 133 ]. When an especially high proportion of chemical crosslinker is used, structural heterogeneity may be introduced, since crosslinkers may be more rapidly incorporated in the growing polymer than other monomers, though this has not always been observed [ 134 ]. Even in the case of RAFT polymerization, evidence of spatial defects in the polymer structure has been observed [ 130 ].…”

“…Even in the case of RAFT polymerization, evidence of spatial defects in the polymer structure has been observed [ 130 ]. For higher resolution structural control, the use of a mask with photolithography and stop-flow lithography permits the synthesis of hydrogels with localized, controlled geometry [ 134 , 135 , 136 ]. Moreover, the molecular imprinting technique has been used to synthesize hydrogels with structural complementarity to biomolecules by including the target biomolecule in the reaction solution during polymerization [ 137 , 138 ].…”