Rational Design of Amphiphilic Diblock Copolymer/MWCNT Surface Modifiers and Their Application for Direct Electrochemical Sensing of DNA

Abstract

<jats:p>We demonstrate the application of amphiphilic ionic poly(n-butylmethacrylate)-block- poly(2-(dimethylamino)ethyl methacrylate) diblock copolymers (PnBMA40-b-PDMAEMA40, PnBMA40-b-PDMAEMA120, PnBMA70-b-PDMAEMA120) for dispersing multiwalled carbon nanotubes (MWCNTs) in aqueous media, a subsequent efficient surface modification of screen-printed electrodes (SPEs), and the application of the modified SPEs for DNA electrochemistry. Stable and fine aqueous dispersions of MWCNTs were obtained with PnBMAx-b-PDMAEMAy diblock copolymers, regardless of the structure of the copolymer and the amount of MWCNTs in the dispersions. The effect of the diblock copolymer structure was important when the dispersions of MWCNTs were deposited as modifying layers on surfaces of SPEs, resulting in considerable increases of the electroactive surface areas and great acceleration of the electron transfer rate. The SPE/(PnBMAx-b-PDMAEMAy + MWCNT) constructs were further exploited for direct electrochemical oxidation of the guanine (G) and adenine (A) residues in a model salmon sperm double-stranded DNA (dsDNA). Two well-defined irreversible oxidation peaks were observed at about +600 and +900 mV, corresponding to the electrochemical oxidation of G and A residues, respectively. A multi-parametric optimization of dsDNA electrochemistry enables one to get the limits of detection (LOD) as low as 5 μg/mL (0.25 μM) and 1 μg/mL (0.05 μM) for G and A residues, respectively. The achieved sensitivity of DNA assay enables quantification of the A and G residues of dsDNA in the presence of human serum and DNA in isolated human leukocytes.</jats:p>

Plasmonic-magnetic nanorobots for SARS-CoV-2 RNA detection through electronic readout

“…To validate the role of Fe 3 O 4 /Au/Ag in the electrochemical analysis, we evaluated the electrooxidation of ssDNA probes with and without NPs ( Figure 3 a and b ). The DPV measurement for 2 μM of ssDNA probes on the SPEs shows a clear oxidative peak at 0.63 V, relying on the irreversible oxidation of G to 8-oxoguanine [43] . In addition, the current intensity of the G oxidation peak was enhanced 1.2-, and 1.4-times when the same concentration of probe DNAs (2 μM) was incubated with Fe 3 O 4 and Fe 3 O 4 /Au/Ag NPs, respectively.…”

Enzymes in the Development of Physico-Chemical Methods for Biomedical Research

“…Такой тип модификации электродов позволил зарегистрировать не только окислительно-восстановительные процессы иона железа гема при потенциале около 0 В, но и электрохимическое окисление аминокислот полипептидной цепи цитохрома с (тирозина и триптофана при +0,6 В), а также необратимое электрохимическое окисление гема при +0,8 В. Это многоточечное обнаружение цитохрома с можно рассматривать как метод распознавания и количественного определения цитохрома с в сложных (био)химических матрицах. Другие примеры демонстрируют эффективную модификацию электродов дисперсия-ми углеродных нанотрубок в водных растворах амфифильных полимеров и сополимеров для количественного электроанализа пуриновых гетероциклических оснований, олигонуклеотидов и двухцепочечной ДНК [40,41], а также лекарственных препаратов диклофенака и ацетаминофена [42].…”

In Situ SERS Sensing by a Laser-Induced Aggregation of Silver Nanoparticles Templated on a Thermoresponsive Polymer

“…Thus, the hydrophilic–hydrophobic balance of PDMAEMA can be changed by varying both the pH and temperature. Linear PDMAEMAs and PDMAEMA-based diblock copolymers have been used as efficient surface modifiers for the design of various types of electrochemical sensors, e.g., for choline [ 25 , 26 , 27 ], phenol [ 28 ], myoglobin [ 29 ], dsDNA [ 30 , 31 ], and drugs [ 32 ], as well as to reveal drug–DNA interactions [ 33 ]. PDMAEMA-based (co/ter)polymers were applied for the non-viral delivery of genetic material into cells [ 34 , 35 ].…”