Editing Biosensor (section)

===Artificial binding proteins===
The use of antibodies as the bio-recognition component of biosensors has several drawbacks. They have high molecular weights and limited stability, contain essential disulfide bonds and are expensive to produce. In one approach to overcome these limitations, recombinant binding fragments ([[Fragment antigen-binding|Fab]], [[Fragment variable|Fv]] or [[scFv]]) or domains (VH, [[VHH]]) of antibodies have been engineered.<ref>{{cite journal|last1=Crivianu-Gaita|first1=V|last2=Thompson|first2=M|title=Aptamers, antibody scFv, and antibody Fab' fragments: An overview and comparison of three of the most versatile biosensor biorecognition elements|journal=Biosens Bioelectron|date=Nov 2016|volume=85|pages=32–45|doi=10.1016/j.bios.2016.04.091|pmid=27155114}}</ref> In another approach, small protein scaffolds with favorable biophysical properties have been engineered to generate artificial families of Antigen Binding Proteins (AgBP), capable of specific binding to different target proteins while retaining the favorable properties of the parent molecule. The elements of the family that specifically bind to a given target antigen, are often selected in vitro by display techniques: [[phage display]], [[ribosome display]], [[yeast display]] or [[mRNA display]]. The artificial binding proteins are much smaller than antibodies (usually less than 100 amino-acid residues), have a strong stability, lack disulfide bonds and can be expressed in high yield in reducing cellular environments like the bacterial cytoplasm, contrary to antibodies and their derivatives.<ref>{{cite journal|last1=Skrlec|first1=K|last2=Strukelj|first2=B|last3=Berlec|first3=A|title=Non-immunoglobulin scaffolds: a focus on their targets|journal=Trends Biotechnol|date=Jul 2015|volume=33|issue=7|pages=408–418|doi=10.1016/j.tibtech.2015.03.012|pmid=25931178}}</ref><ref>{{cite journal|last1=Jost|first1=C|last2=Plückthun|first2=A|title=Engineered proteins with desired specificity: DARPins, other alternative scaffolds and bispecific IgGs|journal=Curr Opin Struct Biol|date=Aug 2014|volume=27|pages=102–112|doi=10.1016/j.sbi.2014.05.011|pmid=25033247}}</ref> They are thus especially suitable to create biosensors.<ref name="pmid19945965">{{cite journal|last1=Brient-Litzler|first1=E|last2=Plückthun|first2=A|last3=Bedouelle|first3=H|title=Knowledge-based design of reagentless fluorescent biosensors from a designed ankyrin repeat protein|journal=Protein Eng Des Sel|date=Apr 2010|volume=23|issue=4|pages=229–241|doi=10.1093/protein/gzp074|pmid=19945965|url=http://doc.rero.ch/record/298976/files/gzp074.pdf|doi-access=free}}</ref><ref name="pmid21565483">{{cite journal|last1=Miranda|first1=FF|last2=Brient-Litzler|first2=E|last3=Zidane|first3=N|last4=Pecorari|first4=F|last5=Bedouelle|first5=Hugues|title=Reagentless fluorescent biosensors from artificial families of antigen binding proteins|journal=Biosens Bioelectron|date=Jun 2011|volume=26|issue=10|pages=4184–4190|doi=10.1016/j.bios.2011.04.030|pmid=21565483}}</ref>