title: The design and development of fluorescent nano-optodes for in vivo glucose monitoring.
abstract: BACKGROUND
  The advent of fluorescent nanosensors has enabled intracellular monitoring of several physiological analytes, which was previously not possible with molecular dyes or other invasive techniques. We have extended the capability of these sensors to include the detection of small molecules with the development of glucose-sensitive nano-optodes. Herein, we discuss the design and development of glucose-sensitive nano-optodes, which have been proven functional both in vitro and in vivo.
  
  
  METHODS
  Throughout the design process, each of the sensor formulations was evaluated based on their response to changes in glucose levels. The percent change in signal, sensor reversibility, and the overall fluorescence intensity were the specific parameters used to assess each formulation.
  
  
  RESULTS
  A hydrophobic boronic acid was selected that yielded a fully reversible fluorescence response to glucose in accordance with the sensor mechanism. The change in fluorescence signal in response to glucose was approximately 11%. The use of different additives or chromophores did not improve the response; however, modifications to the plasticized polymeric membrane extended sensor lifetime.
  
  
  CONCLUSIONS
  Sensors were developed that yielded a dynamic response to glucose and through further modification of the components, sensor lifetime was improved. By following specific design criteria for the macrosensors, the sensors were miniaturized into nano-optodes that track changes in glucose levels in vivo.
authors.affiliation: Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Mary K
authors.initials: MK
authors.lastname: Balaconis
authors.forename: Kelvin
authors.initials: K
authors.lastname: Billingsley
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Dubach
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Cash
authors.forename: Heather A
authors.initials: HA
authors.lastname: Clark
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring / Q000295:instrumentation / Q000379:methods; D003920:Diabetes Mellitus / Q000097:blood* / Q000175:diagnosis / Q000628:therapy; D003940:Diagnostic Techniques, Endocrine / Q000295:instrumentation*; D004305:Dose-Response Relationship, Drug; D004566:Electrodes; D004867:Equipment Design; D005456:Fluorescent Dyes; D006801:Humans; D008954:Models, Biological; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D053758:Nanoparticles; D010968:Plasticizers / Q000737:chemistry / Q000494:pharmacology; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D005456:Fluorescent Dyes; D010968:Plasticizers; D011108:Polymers