title: Multifunctional alginate microspheres for biosensing, drug delivery and magnetic resonance imaging.
abstract: This research aims to develop and investigate a multifunctional implantable system capable of biosensing, drug delivery and magnetic resonance imaging (MRI) for continuous monitoring, controlled anti-inflammatory drug delivery and imaging, respectively. A glucose biosensor, diclofenac sodium (Diclo) and magnetic nanoparticles (MNP) were used as the biosensor component, anti-inflammatory agent and MRI contrast agent, respectively. MNP were synthesized by the co-precipitation technique and loaded with the sensor and drug components into alginate microspheres using a commercial droplet generator. The multifunctional system was then characterized using optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry (VSM) and MRI. The MNP were found to be in the size range of 5-15 nm. The final system, comprising the biosensor, drug and MNP loaded inside alginate microspheres, was found to be in the size range of 10-60 μm. Biosensing studies indicated an excellent glucose response curve, with a regression coefficient of 0.974 (0-10mM of glucose, response time: 4 min). In vitro Diclo release shows that MNP loading in alginate microspheres increases the burst release percentage by 11-12% in both 60 and 10 μm particles. However, the duration of release for 85% drug release decreases with MNP loading by 7 and 6 days for 39 the 60 and 10 μm particles, respectively. Super-paramagnetism was confirmed by VSM, with 2.09 and 1.368 emu g(-1), respectively, for the 60 and 10 μm particles, with no hysteresis. MRI showed significant contrast for both sizes. The particles showed an excellent biocompatibility (>80%) for all combinations of formulations. The system shows a great potential for biosensing with concurrent drug delivery and visualization for biomedical applications.
authors.affiliation: Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400 076 Maharashtra, India.
authors.forename: Abhijeet
authors.initials: A
authors.lastname: Joshi
authors.forename: Sanket
authors.initials: S
authors.lastname: Solanki
authors.forename: Rashmi
authors.initials: R
authors.lastname: Chaudhari
authors.forename: Dhirendra
authors.initials: D
authors.lastname: Bahadur
authors.forename: M
authors.initials: M
authors.lastname: Aslam
authors.forename: Rohit
authors.initials: R
authors.lastname: Srivastava
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics* / Q000494:pharmacology; D015374:Biosensing Techniques / Q000379:methods*; D002460:Cell Line; D003287:Contrast Media / Q000737:chemistry*; D004008:Diclofenac / Q000493:pharmacokinetics* / Q000494:pharmacology; D016503:Drug Delivery Systems; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008422:Materials Testing; D051379:Mice; D008863:Microspheres
chemical_list: D000464:Alginates; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003287:Contrast Media; D006603:Hexuronic Acids; D004008:Diclofenac; D020723:Glucuronic Acid; D005947:Glucose