Biomimics Molecularly Imprinted Polymers Mips

Due to the frequently poor stability (thermal, pH) and short life times of biological components, synthetic molecules with high affinity properties, similar

Table 3 Examples of immunosensors for food contaminants analysis

Analyte

Type and basis

Pesticides and herbicides Atrazine Atrazine Atrazine Atrazine Carbaril Chlorsulfuron

Inhibition assay and electrochemical detection Inhibition assay and optical detection Indirect assay and TIR-fluorescence detection Indirect assay and SPR Indirect assay and SPR

Competitive assay and amperometric detection

Isoproturon Simazine

Indirect assay and TIR-fluorescence detection Competitive immunoreaction and Potentiometrie detection

Triazines Triazines

Triazines

Pesticides

My co toxins Aflatoxins Aflatoxins Deoxynivalenol Fumonisin B1 Ochratoxin A

Inhibition assay and SPR detection Inhibition assay and surface refractive index change detection Flow-through amperometric immunosensor based on peroxidase chip and enzyme channeling system Competitive immunoassays and fluorescence detection

Direct immunoassay and fluorometric detection

Indirect assay and SPR

Indirect assay and SPR

Direct assay and SPR detection

Inhibition assay and SPR detection

Matrix

Sensitivity

Reference

Water 20ng/L [63]

Aqueous solution O.Olng/mL [128] water

Meat extract, milk, 3ng/mL [34] tomatoes, cucumbers, potatoes

Water 15ng/mL [131]

Aqueous solution 1 ng/L [132]

Aqueous solution [133]

Aqueous solution 0.01 ng/L [134]

Aqueous solution 15|j.g/mL [135]

Liquid food samples 5ng/mL [136]

Food borne microorganisms and bacterial toxins Staphylococcal Sandwich assay format

Enterotoxin B

Biosensor arrays

Enterotoxin B Indirect inhibition assay and SPR detection

Botulinum toxoid A Sandwich assay format and Biosensor arrays

Domoic acid Domoic acid Cyanobacter hepatotoxins microcystins E. coli enterotoxin E. coli enterotoxin E. coli 0157:H7

Indirect inhibition assay and SPR Indirect inhibition assay and SPR Recombinant antibodies

QCM SPR

Anti E. coli covalently immobilized to Biodyne membrane and amperometric detection

Tomatoes, sweet corn, green beans, mushrooms and tuna

Food

Tomatoes, sweet corn, green beans, mushrooms and tuna

Shellfish Shellfish

Food and drinking water

Tomato juice (buffered) 0.1 ng/ml

Whole tomatoes

0.1 ng/ml Mushrooms 0.5 ng/ml Sweet corn 0.5 ng/ml Green beans 0.5 ng/ml Tuna 0.5 ng/ml

Tomato juice (buffered) 20

Whole tomatoes 50 Mushrooms 100 Sweet corn 50 Sweet corn juice 50 Green beans 250 Green bean juice 100 Tuna 500 0.5-150 ng/L 2-3.3 ng/L

Food Food

Aqueous suspension

35 pM 70 pM

100 cells/mL

Table 3 (Continued)

Analyte

Type and basis

E. coli 0157:H7

Enterotoxin B Pathogens (Campylobacter jejuni) and mycotoxins Salmonella typhimurium

S. typhimurium

Staphylococcal enterotoxin A Staphylococcal enterotoxin B Staphylococcal enterotoxin B Clostridium botulinum toxins A, B, E and F C. jejuni

Anti E. coli immobilized in a fibre optic and fluorescence detection SPR sensor chip-MALDI-TOF detection Array biosensor

Anti-Salmonella antibody covalently bound to sensor surface refractive index change detection

Anti-Salmonella antibody adsorbed to gold electrode QCR detection

Sandwich assay and evanescent wave detection

Sandwich assay and SPR

Automated fibre optic

Paramagnetic bead-based electrochemiluminescence

Array Biosensor; Sandwich immunoassay

Matrix

Sensitivity

Reference

Beef

Milk, mushrooms Food

Chicken carcass wash fluid

1.10 cfu/mL

Aqueous suspension 1.106 cfu/mL

Food Milk Food Food

Food

50 pg/ml for serotype A [152] to 50-100 pg/ml for serotypes B, E and F Yogurt 1880 [153]

Milk 469

Ground turkey sausage 469

Ground turkey ham 3750

Antibiotics

Chloramphenicol

Chloramphenicol

Ciprofloxacine Enterofloxacine Penicillin and its derivatives Sulphadiazine

Sulphamethazine Sulphamethazine Sulphamethazine Sulphamethazine

Inhibition assay and SPR detection Label-free detection, quartz crystal microbalance measurement Inhibition assay and SPR detection Inhibition assay and SPR detection SPR, direct inhibition assay

Inhibition assay based on indirect immobilization of sulphamethazine to a sensor chip and SPR detection Inhibition assay and SPR detection Inhibition assay and SPR detection Inhibition assay and SPR detection Inhibition assay based on indirect immobilization of Sulphamethazine to a sensor chip and SPR detection

to biological ones, are being introduced. One of the most promising groups of biomimetic materials are molecularly imprinted polymers (MIPs).

MIPs are a class of highly cross-linked polymer-based molecular recognition elements engineered to bind a single target compound or a class of structurally related compounds with high selectivity. By engineering both the binding site and the polymer backbone a wide range of optimized separation phases can be produced. Selectivity is introduced during MIP synthesis in which a template molecule, designed to mimic the analyte, guides the formation of specific cavities or imprints that are sterically and chemically complementary to the desired target analyte(s).

Non-covalent imprinting, in particular, has a great range of applications because of the theoretical lack of restrictions on size, shape or chemical character of the imprinted molecule. The possibility of tailor-made, highly selective receptors at low cost, with good mechanical, thermal and chemical properties makes these polymers appear ideal chemoreceptors. There are great hopes for development of a new generation of chemical sensors using these novel synthetic materials as recognition elements [128,162].

The selected ligand or print molecule is first allowed to establish bond formations with polymerizable functionalities, and the resulting complexes or adducts are subsequently copolymerized with cross-linkers into a rigid polymer. Following the extraction of the print molecule, specific recognition sites are left in the polymer, where the spatial arrangement of the complementary functional entities of the polymer network together with the shape image corresponding to the imprinted molecule.

Molecular imprinted polymers can be prepared by self-assembly, where the prearrangement between the ligand and the functional monomers is formed by non-covalent bond, or metal coordination interactions; or by a preorganized approach, where the aggregates in solution prior to polymerization are maintained by reversible covalent bonds. By use of a high percentage of cross-linker, polymers of substantial rigidity and complete insolubility are obtained.

MIPs allow for selective extraction of low levels of target compounds in the presence of a mixture of potentially interfering matrix components. Compared to biological receptors, MIP polymer recognition systems have the advantage of superior chemical and mechanical stability being compatible with most solvents, pressures and pH conditions. The materials can be engineered for an almost unlimited variety of small molecules, such as drugs, natural products, pharmaceuticals, peptides and other types of molecules.

The main characteristics of these materials is their resistant, mechanical stress, high temperatures and pressures, resistant against treatment with acid, base, or metal ions, stability in a wide range of solvents, and can be used repeatedly.

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