Responsive principles and applications of smart materials in biosensing

Abstract

Biosensing is a rising analytical field for detection of biological indicators using transducing systems. Smart materials can response to external stimuli, and translate the stimuli from biological domains into signals that are readable and quantifiable. Smart materials, such as nanomaterials, photonic crystals and hydrogels have been widely used for biosensing purpose. In this review, we illustrate the incorporation of smart materials in biosensing systems, including the design of responsive materials, their responsive mechanism of biosensing, and their applications in detection of four types of common biomolecules (including glucose, nucleic acids, proteins, and enzymes). In the end, we also illustrate the current challenges and prospective of using smart materials in biosensing research fields.

Keywords: Biosensing; Hydrogel; Nanomaterial; Photonic crystal; Responsive material.

Fig. 1

A zwitterionic hydrogel for simultaneous detection of pH and glucose in wound. (a) Mechanism of sensing of pH and glucose. (b) Visualization of pH values with visible light and glucose concentrations with ultraviolet (UV) light. Reprinted with permission from Ref. [33]. Copyright (2019) Wiley.

Fig. 2

A smart hydrogel system for visualization of glucose in physiological levels. (a) Swelling of hydrogels and (b) SEM images of freeze-dried hydrogels in neutral solution and in acidic solution, respectively. (c) Fluorescence images of smart hydrogels incubated in glucose solutions with different concentrations. (d) Fluorescence images of smart hydrogels implanted in mice with different blood glucose levels. Reprinted with permission from Refs. [34]. Copyright (2019) Elsevier.

Fig. 3

Hydrogel optical fibers for glucose sensing. (a) Structural composition of the glucose-sensitive fiber. Ii, the intensity of laser light that illuminated the hydrogel fiber; Io, the intensity of output light. (b–d) The core of hydrogel fiber is functionalized with 3-APBA, which binds with glucose through its cis-diol group and changes the refractive index of the fiber. Reprinted with permission from Ref. [42]. Copyright (2017) Wiley.

Fig. 4

An inverse opal hydrogel system for colorimetric detection of glucose. (a) Template method for preparing inverse opal hydrogel. (b) SEM image of silica template with colloidal crystal. (c) SEM of the inverse opal hydrogel. (d) Optical responsiveness of the hydrogel sensor to different glucose concentrations. (e) Reusability of the hydrogel sensor. Reprinted with permission from Ref. [49]. Copyright (2019) Royal Society of Chemistry.

Fig. 5

Optical glucose sensing based on nanomaterials. (a) Principle of colorimetric sensing of glucose based on glucose-responsive AuNPs. AuNPs aggregated after incubation at 37 ​°C in solution without glucose, inducing a violet color in solution (b). AuNPs dispersed after incubation at 37 ​°C in glucose solution, and the solution remained a red color (c). Reprinted with permission from Ref. [52]. Copyright (2013) Wiley. (d) Principle of colorimetric detection of glucose using AuNRs. (e) Image of glucose solutions at various concentrations with addition of AuNRs. Reprinted with permission from Ref. [54]. Copyright (2013) Royal Society of Chemistry.

Fig. 6

Detection of nucleic acid based on nanomaterials. (a) A hybrid nanoprobe for visual detection of viral RNA replication in cells. (b) Merged fluorescentce and phase contrast images of cells that infected with different quantities of virus. Reprinted with permission from Ref. [60]. Copyrithg (2010) Royal Society of Chemistry. (c–d) DNA detection based on two types of self-assembled NP pyramids. Reprinted with permission from Ref. [61]. Copyrithg (2014) Wiley.

Fig. 7

MoS₂-integrated SCCBs for screening of multiplex miRNA. (a) Process of miRNA detection on MoS₂ platform. (b) Detection of multiplex miRNA based on MoS₂-integrated SCCBs. (c–e) Bright field images and (f–h) fluorescence images of three types of MoS₂-integrated SCCBs after incubating with target miRNA: (c, f) with one type of miRNA; (d, g) with two types of miRNA; (e, h) with three types of miRNA. Reprinted with permission from Ref. [65]. Copyright (2019) Elsevier.

Fig. 8

Detection of EBOV glycoprotein with nanozyme-strip. (a) Design of standard colloidal gold strip. (b) Design of nanozyme-strip with Fe₃O₄ MNPs. The detection of the glycoprotein of EBOV using standard colloidal gold strip (c) and using nanozyme-strip (d). Reprinted with permission from Ref. [72]. Copyright (2015) Elsevier.

Fig. 9

PC-encapsulated hydrogels for responsive detection of lectin. (a) Synthesis of carbohydrate hydrogels. (b) Protein recognition of the hydrogels results in hydrogel shrinkage, exhibiting an optical readout from the hydrogel (c). (a) and (b) are reprinted with permission from Ref. [78]. Copyright (2017) American Chemical Society. (c) is reprinted with permission from Refs. [77]. Copyright (2015) American Chemical Society.

Fig. 10

Encoded MNs with PC barcodes for detection of ISF biomarkers. (a) Preparation of the encoded MNs. (b) Application of the MNs in detection of ISF. (c–f) Optical images of MNs with multiplex barcodes with different structural colors. Blue, green and red barcodes were used for detection of IL-6, IL-1β and TNF-α, respectively. Reprinted with permission from Ref. [81]. Copyright (2019) Wiley.

Fig. 11

Nanomaterials used for detection of protease. (a) QDs and (b) plasmonic AuNPs employed as signal transducers during the detection of protease. Reprinted with permission from Refs. [10]. Copyright (2014) American Association for the Advancement of Science.

Fig. 12

Hydrogels used for detection of enzymes. (a) Detection of thrombin through induced volume change of a super-aptamer hydrogel. Reprinted with permission from Ref. [87]. Copyright (2013) American Chemical Society. (b) PC hydrogels used for detection of different enzymes. Reprinted with permission from Ref. [88]. Copyright (2020) American Chemical Society.