RESUMEN
A rapid and one-pot synthesis of poly 3-thiopheneacetic acid (PTAA) functionalized polyurea polymer dots (Pdots) using polyethyleneimine and isophorone diisocyanate is reported. The one-pot mini-emulsion polymerization technique yielded Pdots with an average diameter of ~20 nm. The size, shape, and concentration of the surface functional groups could be controlled by altering the synthesis parameters such as ultrasonication time, concentration of the surfactant, and crosslinking agent, and the types of isocyanates utilized for the synthesis. Colloidal properties of Pdots were characterized using dynamic light scattering and zeta potential measurements. The spherical geometry of Pdots was confirmed by scanning electron microscopy. The Pdots were post-functionalized by 1,4,7,10 tetraazacyclododecane-1,4,7,10-tetraacetic acid for chelating gadolinium nanoparticles (Gd3+) that provide magnetic properties to the Pdots. Thus, the synthesized Pdots possess fluorescent and magnetic properties, imparted by PTAA and Gd3+, respectively. Fluorescence spectroscopy and microscopy revealed that the synthesized dual-functional Gd3+-Pdots exhibited detectable fluorescent signals even at lower concentrations. Magnetic levitation experiments indicated that the Gd3+-Pdots could be easily manipulated via an external magnetic field. These findings illustrate that the dua- functional Gd3+-Pdots could be potentially utilized as fluorescent reporters that can be magnetically manipulated for bioimaging applications.
RESUMEN
Profiling of advanced glycation end products (AGEs) is an emerging area of clinical significance for disease diagnosis and prognosis. Typically, concentrations of AGEs are estimated in laboratories by trained personnel using sophisticated equipment. Herein, a facile approach for colorimetric and fluorometric profiling of AGEs is reported for rapid and on-site analysis. The concentrations of AGE levels in plasma are estimated via changes in optical properties of polythiophenes (PTs) upon interaction with aptamers (Apts) in the presence and in the absence of AGEs. To validate the proposed approach, glyceraldehyde-derived AGEs (AGE class 1 [AGE1]), the biomarker associated with cardiovascular diseases and diabetes, are used as a model system. Colorimetric analysis yielded linear responses for AGE1 for clinically relevant concentration ranges between 1.5 and 300 µg/mL with a limit of detection (LOD) of â¼1.3 µg/mL. Subsequently, an approach utilizing PTs with four different pendant groups in conjunction with four different Apts is demonstrated for qualitative colorimetric profiling and for quantitative fluorometric profiling of up to four AGEs in clinical matrices. Principal component analysis (PCA) of fluorometric responses of AGE-spiked samples yielded distinct responses for the different AGEs tested. Thus, the proposed approach ascertains rapid profiling of spiked AGEs in plasma samples without the requirement of preanalytical processing and advanced instrumentation, thereby facilitating on-site diagnosis.