Target-Initiated Great Change in Electrochemical Steric Hindrance for an Assay of Granzyme B Activity

Abstract

To improve long-term graft patient outcomes and develop more effective antirejection therapies, noninvasive monitoring of acute cellular rejection (ACR) after organ transplantation is urgently needed. As a biomarker of ACR, Granzyme B (GrB) is expected to be applied in the noninvasive monitoring of ACR. Herein, we have developed a method for detecting the GrB activity based on the target-initiated great change in electrochemical steric hindrance by designing a nanoprobe. The nanoprobe is prepared by conjugating a specific peptide, which is responsive to GrB cleavage activity, to gold nanoparticles (AuNPs). Meanwhile, a piece of DNA sequence with G-quadruplex (G4) is attached at the distal end of the peptide. Upon exposure to GrB, the peptide substrate is cleaved to eliminate the steric hindrance between inter-nanoprobes as well as nanoprobe and DNA tetrahedron (TDN), allowing the released DNA strand to hybridize with TDN, giving sensitive signal output. The method can also be used to detect GrB activity in complex biological settings, so it has a great potential for monitoring GrB activity in the blood or urine of graft patients.

Electrochemical Aptasensing of SARS-CoV-2 Based on Triangular Prism DNA Nanostructures and Dumbbell Hybridization Chain Reaction

“…To verify the feasibility of the electrochemical sensing strategy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) are carried out to identify the step-wise properties of modified electrodes. 25 As depicted in the nyquist plots, a bare gold electrode shows excellent electrical conductivity reflected by the straight line; after being modified with TPDNA, a semicircle domain is generated, which is due to the repellent reaction between immobilized DNA and [Fe(CN) 6 ] 3–/4– ; 26 after further incubation with CP, a slight larger semicircle demonstrates increased charge-transfer resistance by the attached CP; in the presence of the target, CP is released and DHCR can be carried out with stacked fuel strands at the electrode interface, leading to significantly an increased semicircle domain. On the other hand, in the absence of the target, the diameter of the semicircle is nearly the same as that of the TPDNA modified electrode, verifying that DHCR cannot be carried out without a target protein.…”

An electrochemical biosensor for SARS-CoV-2 detection via its papain-like cysteine protease and the protease inhibitor screening

“…The synthesis of 17 nm gold nanoparticles was based on a previous study using the sodium citrate reduction method [45] , [46] . 40 mL of 0.5 mM HAuCl 4 aqueous solution was boiled under stirring for 10 minutes, and then 4 mL of 19.4 mM sodium citrate solution was quickly added to the boiling HAuCl 4 solution and stirred.…”

“…The synthesis of 3.5 nm AuNPs is based on previous studies [46] , [47] . 0.25 mL of 25 mM HAuCl 4 was added to a mixed solution containing 37.5 mL of 2.2 nM sodium citrate (0.0243 g) and 0.025 mL of 2.5 mM tannic acid (0.0002 g), which were mixed and stirred at 70 °C for 30 minutes.…”

Emerging Biomaterials Imaging Antitumor Immune Response

“…In addition to using granzyme B to predict the response rate of tumor immunotherapy, since recipient T cells secrete granzyme in large volumes to attack the donor‐derived graft during acute cellular rejection (ACR), granzyme B can also be used to monitor ACR and myocarditis. [ 221,236 ] The early detection of transplant rejection is essential for long‐term patient survival. [ 237 ] To overcome the tedious biopsy process, noninvasive rejection can be monitored early using fluorescent probes to monitor the activity of granzyme B produced by recipient T cells.…”

“…[219,220] Multiple nanoprobes have been used to monitor granzyme B activity in patient blood and cancer progression; however, the visualization of this dynamic process is arduous. [221,222] Molecular optical probes allow the specific visualization of small molecules during immunization. Therefore, a specific granzyme B reagent can be developed to predict the ability to recognize active CTLs and quantitatively measure the kinetics of immune responses (Table 4).…”