Overview of Optical Biosensors for Early Cancer Detection: Fundamentals, Applications and Future Perspectives

Abstract

Conventional cancer detection and treatment methodologies are based on surgical, chemical and radiational processes, which are expensive, time consuming and painful. Therefore, great interest has been directed toward developing sensitive, inexpensive and rapid techniques for early cancer detection. Optical biosensors have advantages in terms of high sensitivity and being label free with a compact size. In this review paper, the state of the art of optical biosensors for early cancer detection is presented in detail. The basic idea, sensitivity analysis, advantages and limitations of the optical biosensors are discussed. This includes optical biosensors based on plasmonic waveguides, photonic crystal fibers, slot waveguides and metamaterials. Further, the traditional optical methods, such as the colorimetric technique, optical coherence tomography, surface-enhanced Raman spectroscopy and reflectometric interference spectroscopy, are addressed.

Keywords: early cancer detection; label free; metamaterial; optical biosensors; plasmonic biosensor.

Figure 7

(a) A schematic illustration of evanescent-wave-based sensing technique where ${\mathrm{n}}_2<{\mathrm{n}}_1$ [63], (b) Image of a sensor cell and SEM image of a 1.0 mm thick optical microfiber [64], (c) A cross-sectional view along one of the sensing patches [65], (d) Schematic of planar waveguide evanescent-wave-based immune sensing platform [68].

Figure 1

Different types of optical sensing mechanisms.

Figure 2

(a) Front side and back side of the i-Genbox LAMP box [21], (b) Left—mini-centrifuge used for DNA precipitation and preparation of the LAMP reaction mix; right—sous-vide stick heating water to different temperatures in a rubber ice bucket; bottom—results of 6 samples to test the simple setup relying on visual readout [22], (c) A schematic illustration of LAMP-GNP/DNA probe assay [23], (d) The interface of the smartphone app for hue value quantitative measurement [20] and (e) LAMP primer sets α and β, which can enable the amplification of synthetic samples of SARS-CoV-2 nucleic acids in a wide range of template concentrations [24].

Figure 3

(a) Photographs of color change and typical UV–vis spectra upon addition of different concentrations of miR-21 [30], (b) UV−Vis absorption spectra of C-AuNPs and P-AuNPs. Inset: colors of AuNPs solution [27], (c) UV-vis absorption spectra of the reduction in 4-NP by NaBH4 in the presence of Au/Bi2Se3 nanosheets, with inserted photograph showing the color change of reduction in 4-NP [26], (d) The optical-fiber-based LSPR [29], (e) Evolution of colorimetric changes of PDDA-AgNPs, PDDA-AuNPs and PDDA-(Ag+Au)NPs [31].

Figure 4

(a) Schematic diagram of a typical first-generation free-space optics-based optical coherence tomography setup [32], (b) Complete low-cost OCT system with PC, touchscreen and scanner [33], (c) Schematics of the optical palpation setup for an inclusion phantom [34], (d) Setup of the frequency response measurement of the fiber optic sensor [35], (e) Schematic of phase-sensitive OCT [41] and (f) A complete compact and mobile FF-OCT fingerprint sensor system, which includes the sensor, the microcomputer and the screen. [42].

Figure 5

(a) Au/HCP-PS monolayer SERS biosensor chip [44], (b) Experimental setup for continuous SERS measurements in the gas phase [46], (c) Schematic illustration of the liquid phase detection using SLIPSERS [49] and (d) SERS sensor for the selective detection of histamine [51].

Figure 6

(a) Biopsy needle with integrated optical fibers [55], (b) Microfluidic nanoporous RIfS device [57], (c) Schematic illustration of binding event between human serum albumin (HSA) and quercetin in the environment of fresh primer binding sites (PBS) [60] and (d) The structural diagram of the ${\mathrm{Cu}}^{2+}$ sensing part. [61].

Figure 8

Prism coupling to SPPs based on evanescent wave through total internal reflection using (a) Otto and (b) Kretschmann configurations. The possible light paths for excitation in the prism coupling and SPP dispersion curve are shown in (c).

Figure 9

Resonance peaks detected based on prism coupling.

Figure 10

The cross-section of the (a) Self-calibration biosensor [80], (b) Side-polished D-shaped biosensor [84], (c) Ti${\mathrm{O}}_2$ sensor [85], (d) ITO-based PCF sensor [86], (e) Bended PCF-based SPR sensor [87] and (f) Twin-core PCF sensor [90].

Figure 11

Cross-section of the (a) Hybrid plasmonic refractive index sensor with the nano slit array [100], (b) Vertical slot waveguide biosensor [96], (c) DNA HPSW biosensor [106], (d) DSHP waveguide covered with test liquid [110] and (e) Compact parallel biosensor [112].

Figure 12

(a) Top view of a single-cell split ring resonator [120], (b) Top view of the latch array [120] and (c) Side view of the sensor to show the effective values for the relative permittivity and permeability for achieving the matching condition.

Figure 13

Schematic structures for the (a) Hexagonal cancer biosensor [120], (b) Microfluidic sensor [125], (c) Graphene metamaterial absorber [127], (d) Double corrugated metamaterial biosensor [128], (e) Unit cell of the F-shaped metamaterial sensor [129] and (f) Spoof surface plasmon metamaterials (MMs) structure [131].