Editing Biosensor (section)

==Placement of biosensors==
The appropriate placement of biosensors depends on their field of application, which may roughly be divided into [[biotechnology]], [[agriculture]], [[food technology]] and [[biomedicine]].

In biotechnology, analysis of the chemical composition of [[microbial culture|cultivation]] broth can be conducted in-line, on-line, at-line and off-line. As outlined by the US Food and Drug Administration ([[FDA]]) the sample is not removed from the process stream for in-line sensors, while it is diverted from the manufacturing process for on-line measurements. For at-line sensors the sample may be removed and analyzed in close proximity to the process stream.<ref>{{Citation | title = Guidance for Industry: PAT — A Framework for Innovative Pharmaceutical Development, Manufacturing, and Quality Assurance  | editor = US Department of Health and Human Services | editor2 = Food and Drug Administration | editor3 = Center for Drug Evaluation and Research | editor4 = Center for Veterinary Medicine | editor5 = Office of Regulatory Affairs | date = September 2004 | url = http://www.gmp-compliance.org/guidemgr/files/PAT-FDA-6419FNL.PDF }}</ref> An example of the latter is the monitoring of lactose in a dairy processing plant.<ref>Pasco, Neil; Glithero, Nick. Lactose at-line biosensor 1st viable industrial biosensor? {{cite web|url=http://nzbio2012.co.nz/content/nzbio2012/images/3_Biosensor_Development_for_Detecting_Lactose_in_Dairy_Wastewater__Neil_Pasco.pdf |title=Archived copy |access-date=9 February 2016 |archive-url=https://web.archive.org/web/20130208062347/http://nzbio2012.co.nz/content/nzbio2012/images/3_Biosensor_Development_for_Detecting_Lactose_in_Dairy_Wastewater__Neil_Pasco.pdf |archive-date=8 February 2013 |df=dmy }} (accessed 30 January 2013).</ref> Off-line biosensors compare to [[bioanalysis|bioanalytical techniques]] that are not operating in the field, but in the laboratory. These techniques are mainly used in agriculture, food technology and biomedicine.

In medical applications biosensors are generally categorized as ''[[in vitro]]'' and ''[[in vivo]]'' systems. An ''in vitro'', biosensor measurement takes place in a test tube, a culture dish, a microtiter plate or elsewhere outside a living organism. The sensor uses a bioreceptor and transducer as outlined above. An example of an ''in vitro'' biosensor is an enzyme-conductimetric biosensor for [[blood glucose monitoring]]. There is a challenge to create a biosensor that operates by the principle of [[point-of-care testing]], i.e. at the location where the test is needed.<ref>{{cite journal | last = Kling | first = Jim | year = 2006 | title = Moving diagnostics from the bench to the bedside | journal = Nat. Biotechnol. | volume = 24 | issue = 8| pages = 891–893 | doi = 10.1038/nbt0806-891| pmid = 16900120 | s2cid = 32776079 }}</ref><ref>{{Cite journal|last1=Quesada-González|first1=Daniel|last2=Merkoçi|first2=Arben|date=2018|title=Nanomaterial-based devices for point-of-care diagnostic applications|journal=Chemical Society Reviews|volume=47|issue=13|pages=4697–4709|doi=10.1039/C7CS00837F|pmid=29770813|issn=0306-0012|url=http://ddd.uab.cat/record/224237}}</ref> Development of wearable biosensors is among such studies.<ref>{{cite journal | doi = 10.1002/elan.201200349  | title = Wearable Electrochemical Sensors and Biosensors: A Review  | journal = Electroanalysis  | volume = 25  | pages = 29–46  | year = 2013  | last1 = Windmiller  | first1 = Joshua Ray  | last2 = Wang  | first2 = Joseph  }}</ref> The elimination of lab testing can save time and money. An application of a POCT biosensor can be for the testing of [[HIV]] in areas where it is difficult for patients to be tested. A biosensor can be sent directly to the location and a quick and easy test can be used. 
[[File:Glucose biosensor implant.png|thumb|Biosensor implant for glucose monitoring in subcutaneous tissue (59x45x8 mm). Electronic components are hermetically enclosed in a Ti casing, while antenna and sensor probe are moulded into the epoxy header.<ref name= MIM2016>{{cite journal | last1 = Birkholz | first1 = Mario | last2 = Glogener | first2 = Paul | last3 = Glös | first3 = Franziska | last4 = Basmer | first4 = Thomas | last5 = Theuer | first5 = Lorenz | year = 2016 | title = Continuously operating biosensor and its integration into a hermetically sealed medical implant | journal = Micromachines | volume = 7 | issue = 10 | pages = 183 | doi = 10.3390/mi7100183| pmid = 30404356 | pmc = 6190112 | doi-access = free }}</ref>]]

An ''in vivo'' biosensor is an [[implant (medicine)|implantable device]] that operates inside the body. Of course, biosensor implants have to fulfill the strict regulations on [[sterilization (microbiology)|sterilization]] in order to avoid an initial inflammatory response after implantation. The second concern relates to the long-term [[biocompatibility]], i.e. the unharmful interaction with the body environment during the intended period of use.<ref>{{cite journal | last1 = Kotanen | first1 = Christian N. | last2 = Gabriel Moussy | first2 = Francis | last3 = Carrara | first3 = Sandro | last4 = Guiseppi-Elie | first4 = Anthony | year = 2012 | title = Implantable enzyme amperometric biosensors | journal = Biosensors and Bioelectronics | volume = 35 | issue = 1| pages = 14–26 | doi = 10.1016/j.bios.2012.03.016 | pmid=22516142}}</ref> Another issue that arises is failure. If there is failure, the device must be removed and replaced, causing additional surgery. An example for application of an in vivo biosensor would be the insulin monitoring within the body, which is not available yet.

Most advanced biosensor implants have been developed for the continuous monitoring of glucose.<ref>{{cite journal | last1 = Gough | first1 = David A. | last2 = Kumosa | first2 = Lucas S. | last3 = Routh | first3 = Timothy L. | last4 = Lin | first4 = Joe T. | last5 = Lucisano | first5 = Joseph Y. | year = 2010 | title = Function of an Implanted Tissue Glucose Sensor for More than 1 Year in Animals | journal = Sci. Transl. Med. | volume = 2 | issue = 42 | pages = 42ra53 | doi = 10.1126/scitranslmed.3001148 | pmid=20668297 | pmc=4528300}}</ref><ref>{{cite journal | last1 = Mortellaro | first1 = Mark | last2 = DeHennis | first2 = Andrew | year = 2014 | title = Performance characterization of an abiotic and fluorescent-based continuous glucose monitoring system in patients with type 1 diabetes | journal = Biosens. Bioelectron. | volume = 61 | pages = 227–231 | doi = 10.1016/j.bios.2014.05.022 | pmid = 24906080 | doi-access = free }}</ref> The figure displays a device, for which a Ti casing and a battery as established for cardiovascular implants like [[pacemakers]] and [[implantable cardioverter-defibrillator|defibrillators]] is used.<ref name="MIM2016"/> Its size is determined by the battery as required for a lifetime of one year. Measured glucose data will be transmitted wirelessly out of the body within the [[Medical Implant Communication Service|MICS]] 402-405&nbsp;MHz band as approved for medical implants.

Biosensors can also be integrated into mobile phone systems, making them user-friendly and accessible to a large number of users.<ref>{{cite journal | last1 = Quesada-González | first1 = Daniel | last2 = Merkoçi | first2 = Arben | year = 2016 | title = Mobile phone-based biosensing: An emerging "diagnostic and communication" technology | journal = Biosensors & Bioelectronics | volume = 92| pages = 549–562| doi=10.1016/j.bios.2016.10.062 | pmid=27836593| url = http://ddd.uab.cat/record/194894 }}</ref>