Table 4.

Advantages and disadvantages of potential binders for SPR analysis of PSP toxins.

Binder	Advantages	Disadvantages
Chemosensors	Non-animal-based binders Can be incorporated into self-assembly monolayers for sensing on a surface	Lower binding affinity than antibodies No correlation between the binding intensity and biological response or toxicity
Molecular imprinted polymers (MIPS)	Non-animal-based binder Target analyte defines its own recognition site Stable at extreme temperature and pH Show specificity in natural systems Adaptable and flexible in their use Low cost and ease of manufacture May be used in non-aqueous media or aggressive environments	May be sensitive to small alterations in target analyte structure and properties Show non-specific binding Diversity of binding sites Template bleeding requires suitable template analogue for imprinting and affects quantitative applications Generally lower binding affinities than antibodies
Aptamers	Nucleic acid aptamers are non-animalbased binders produced by chemical synthesis resulting in limited batch to batch variation Selectively bind to low molecular weight compounds Binding affinities of aptamers are in the μM to nM range and kinetic parameters can be altered on demand Toxins that do not illicit a good immune response can be used to generate high-affinity aptamers Aptamers are stable for long-term storage and can be transported at ambient temperature Selection conditions can be manipulated to obtain aptamers with properties desirable for in vitro assays, e.g. non-physiological buffers, solvents, etc. Reporter molecules can be attached to aptamers at precise locations so as not to affect binding	Aptamers are costly to generate and long aptamer sequences are difficult to achieve DNA aptamers have a smaller range of three-dimensional structures obtainable compared with RNA aptamers but they can bind their target to the entire sequence DNA and RNA aptamers are susceptible to enzymatic degradation by nucleases, thus requiring highly pure environments. This can be overcome Peptide aptamers are constrained to the scaffold protein so they are less flexible, which may affect their effectiveness. Only the variable range is used for binding Peptide aptamers require biological systems for selection purposes