A magnetic resonance tuning sensor for the MRI detection of biological targets. Issue 11 (November 2018)

• Record Type: Journal Article
• Authors: Shin, Tae-Hyun; Kang, Sunghwi; Park, Sohyeon; Choi, Jin-sil; Kim, Pan; Cheon, Jinwoo
• Is Part Of: Nature protocols. Volume 13:Issue 11(2018)
• Page Start: 2664
• Page End: 2684
• Publication Date: 2018-11
• Subjects: Biology -- Methodology -- Periodicals; Chemistry -- MethodologyPeriodicals; Biology -- Handbooks, manuals, etc; Chemistry -- Handbooks, manuals, etc; 570.28
• DOI: 10.1038/s41596-018-0057-y
• Languages: English
• ISSNs: 1754-2189

Abstract

Abstract Sensors that detect specific molecules of interest in a living organism can be useful tools for studying biological functions and diseases. Here, we provide a protocol for the construction of nanosensors that can noninvasively detect biologically important targets with magnetic resonance imaging (MRI). The key operating principle of these sensors is magnetic resonance tuning (MRET), a distance-dependent phenomenon occurring between a superparamagnetic quencher and a paramagnetic enhancer. The change in distance between the two magnetic components modulates the longitudinal (T 1 ) relaxivity of the enhancer. In this MRET sensor, distance variation is achieved by interactive linkers that undergo binding, cleavage, or folding/unfolding upon their interaction with target molecules. By the modular incorporation of suitable linkers, the MRET sensor can be applied to a wide range of targets. We showcase three examples of MRET sensors for enzymes, nucleic acid sequences, and pH. This protocol comprises three stages: (i) chemical synthesis and surface modification of the quencher, (ii) conjugation with interactive linkers and enhancers, and (iii) MRI sensing of biological targets. The entire procedure takes up to 3 d. This protocol describes the synthesis of magnetic resonance tuning (MRET) sensors. The sensors consist of two magnetic components separated by a linker and can be modularly designed for targets such as enzymes, nucleic acid sequences, and pH values.