A Genosensor Based on the Modification of a Microcantilever: A Review

Abstract

When the free end of a microcantilever is modified by a genetic probe, this sensor can be used for a wider range of applications, such as for chemical analysis, biological testing, pharmaceutical screening, and environmental monitoring. In this paper, to clarify the preparation and detection process of a microcantilever sensor with genetic probe modification, the core procedures, such as probe immobilization, complementary hybridization, and signal extraction and processing, are combined and compared. Then, to reveal the microcantilever's detection mechanism and analysis, the influencing factors of testing results, the theoretical research, including the deflection principle, the establishment and verification of a detection model, as well as environmental influencing factors are summarized. Next, to demonstrate the application results of the genetic-probe-modified sensors, based on the classification of detection targets, the application status of other substances except nucleic acid, virus, bacteria and cells is not introduced. Finally, by enumerating the application results of a genetic-probe-modified microcantilever combined with a microfluidic chip, the future development direction of this technology is surveyed. It is hoped that this review will contribute to the future design of a genetic-probe-modified microcantilever, with further exploration of the sensitive mechanism, optimization of the design and processing methods, expansion of the application fields, and promotion of practical application.

Keywords: application field; detection principle; environmental impact factors; genetic probe; microcantilever; sensitive modification.

Figure 1

Detection procedure of the genetic-probe-modified microcantilever sensor: (A) probe immobilization; (B) complementary hybridization; (C) signal processing.

Figure 2

The DNA detection protocol of a spin microcantilever based on in situ hybridization [57].

Figure 3

Processes of GNPs combine hybridization information [59].

Figure 4

The aptamer-modified microcantilever sensor for cocaine detection. (A) Schematic representation of the sensing strategy for cocaine detection. (B) Optical circuit of differential surface stress sensor. Laser wavelength is 635 nm. A pair of microlens arrays with lenses of 240 and 900 μm diameter, and pitches of 250 μm and 1 mm, respectively, were used to direct the beams toward the sensing/reference pair [65].

Figure 5

SEM images of microcantilever based on electrical measurement methods. (A) Microcantilever with comb capacitance detection, driver electrode, and CMOS signal amplification circuit proposed by Forsen et al. in 2005 [70]. (B) In 2007, Lee et al. achieved self-excited dynamic detection of the poly T-sequence DNA and a variety of proteins by using a PZT microcantilever [72]. (C) In 2021, Tian et al., developed a polyimide (PI)/Si/SiO₂ based piezoresistive microcantilever biosensor to achieve a trace level detection for aflatoxin B1 [75].

Figure 6

Improved scheme of electric signal extraction method. (A) Schematic of the interaction between probe and target molecules on an embedded-MOSFET cantilever system [76]; (B) schematic diagram of infrared pyroelectric detection system based on a PZT microcantilever [77]; (C) piezoresistive microcantilever sensor chip design with temperature compensation resistance [78].

Figure 7

(A) Schematic diagram of the hybrid spin microcantilever system in the presence of a strong pump field and a weak probe field; (B) the energy level diagram of the coupling between the NV center spin and the microcantilever [57].

Figure 8

Schematic illustration of the Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation detection using MutS, AuNP, and resonator [127].

Figure 9

Schematic of the nanomechanical method of SARS-CoV-2 detection from sampling to diagnosis. (A) Sample collection from infected individuals; (B) RNA extraction of SARS-CoV-2; (C) differential modification of microcantilever array with PNA. Four microcantilevers in an array were functionalized with PNA, and the other four were used for in situ comparison. (D) Detecting with nanomechanical devices. Eight semiconductor lasers sequentially emitted a stable beam focused on the tip of each microcantilever in the array, while a position-sensitive detector (PSD) was responsible for monitoring the deflection of each microcantilever in real time by measuring the movement of the reflected light. (E) Early diagnosis of COVID-19 within 60 min [137].

Figure 10

A schematic representation of the BMC and its multimode operation [143]. (A) BMC filled with bacteria supported on a silicon substrate; (B) SEM image of the cross section of an inlet; (C) cross section of microchannel on BMC modified with mAb or AMP; (D) fluorescent image from the top side of the BMC, filled with bacteria; (E) SEM image of the tip of the BMC; (F) deflection of BMC caused by heat when bacteria absorb infrared light; (G) resonance frequency changes with the quality of bacteria; (H) selective absorption of infrared light by bacteria.

Figure 11

(A) A schematic illustration of the mechanism of HepG2 cells determined by a microcantilever array sensor; (B) functionalization procedure of microcantilevers by immersing into capillaries containing TLSIIa aptamers; (C) AFM topography image of aptamers (1 μmol/L) on gold surface (2 × 2 μm) [45].

Figure 12

Nanomechanical detection of cancer cells in a model of breast cancer. (A) Schematic diagram showing the attachment of malignant cells to the cantilever surface; (B) close-up image of the cell–receptor complex on the nanomechanical cantilever surface; (C) attachment of stained MDA-MB231 breast cancer cells (blue) on the working microbeam and the reference microbeam; (D) SEM of a cancer cell attached to the measuring nanomechanical cantilever sensor [151].

Figure 13

(A) Picture of the complete setup; (B) schematic view of magnet-based microfluidic inlet assembly; (C) a polymer disc connected to nozzles through rare earth magnets; (D) installation schematic of the chip on the titanium alloy bracket; (E) installation schematic of polymer chip composed of PDMS and PMMA [156].

Figure 14

(A) Integrated testing equipment of Lechuga et al. [67]; (B) integrated testing equipment of Ricciardi et al. [175]; (C) integrated testing equipment of Huang et al. [176]; (D) integrated testing equipment of Khemthongcharoen et al. [142]; (E) integrated testing equipment of Wang et al. [184].