Imprinting of Microorganisms for Biosensor Applications

Abstract

There is a growing need for selective recognition of microorganisms in complex samples due to the rapidly emerging importance of detecting them in various matrices. Most of the conventional methods used to identify microorganisms are time-consuming, laborious and expensive. In recent years, many efforts have been put forth to develop alternative methods for the detection of microorganisms. These methods include use of various components such as silica nanoparticles, microfluidics, liquid crystals, carbon nanotubes which could be integrated with sensor technology in order to detect microorganisms. In many of these publications antibodies were used as recognition elements by means of specific interactions between the target cell and the binding site of the antibody for the purpose of cell recognition and detection. Even though natural antibodies have high selectivity and sensitivity, they have limited stability and tend to denature in conditions outside the physiological range. Among different approaches, biomimetic materials having superior properties have been used in creating artificial systems. Molecular imprinting is a well suited technique serving the purpose to develop highly selective sensing devices. Molecularly imprinted polymers defined as artificial recognition elements are of growing interest for applications in several sectors of life science involving the investigations on detecting molecules of specific interest. These polymers have attractive properties such as high bio-recognition capability, mechanical and chemical stability, easy preparation and low cost which make them superior over natural recognition reagents. This review summarizes the recent advances in the detection and quantification of microorganisms by emphasizing the molecular imprinting technology and its applications in the development of sensor strategies.

Keywords: applications; biosensor; microorganism imprinting.

Figure 1

Schematic representation of microcontact imprinting of E. coli onto the polymer modified surfaces. (A) preparation of electrode surface; (B) preparation of bacteria stamps; (C) production of the microcontact imprinting (reproduced from [60] with permission).

Figure 2

SEM images of bare gold electrode (A) −50,000×, and E. coli imprinted electrode (B) −10,000×, (C,D) −50,000× magnifications (reproduced from [60] with permission).

Figure 3

(A) Capacitive sensorgram of the E. coli imprinted electrode (concentration of E. coli: 1.0 × 10⁷ CFU/mL), ΔC: change in capacitance; (B) calibration curve of E. coli obtained at a concentration range of (1.0 × 10²–1.0 × 10⁷ CFU/mL) under optimum conditions, LOD: limit of detection, flow rate: 100 μL/min; sample volume: 500 μL; running buffer: 10 mM sodium phosphate, pH: 7.4; regeneration buffer: pure ethyl alcohol, 10 mg/mL lysozyme solution (in 10 mM Tris-HCl buffer, pH 8.0, with 1 mM EDTA) and 50 mM glycine-HCl, pH 2.5; T 25 °C. (Reproduced from [60] with permission).