Nanomotors for Nucleic Acid, Proteins, Pollutants and Cells Detection

FOF1-ATP synthase molecular motor biosensor for miRNA detection of colon cancer

AIMS

To establish a F_OF1-ATP synthase molecular motor biosensor to accurately identify colon cancer miRNAs.

MAIN METHODS

The F_OF1-ATP synthase molecular motor is extracted by fragmentation-centrifugation and connected to the colon cancer-specific miR-17 capture probe in the manner of the ε subunit-biotin-streptavidin-biotin system. Signal probes are designed for dual-signal characterization to increase detection accuracy. The F_OF1-ATPase rotation rate decreases when the signaling and capture probes are combined with the target miRNA, resulting in a decrease in ATP synthesis. miR-17 concentrations are determined by changes in ATP-mediated chemiluminescence intensity and signal probe-mediated OD_450nm.

KEY FINDINGS

The chemiluminescence intensity and OD_450nm show a good linear relationship with the miR-17 concentration in the range of 5 to 200 nmol L^-1 (R² = 0.9985, 0.9989). The colon cancer mouse model is established for the blood samples, and miR-17 in serum and RNA extracts is quantitatively determined using the constructed sensor.

SIGNIFICANCE

The results are consistent with colon cancer progression, and the low concentration of miR-17 detecting accuracy is comparable to the PCR assay. In conclusion, the developed method is a direct, rapid, and promising method for miRNA detection of colon cancer.

Fluorescence Detection of miRNA-21 Using Au/Pt Bimetallic Tubular Micromotors Driven by Chemical and Surface Acoustic Wave Forces

In this study, surface acoustic wave (SAW) systems are described for the removal of molecules that are unbound to micromotors, thereby lowering the detection limit of the cancer-related biomarker miRNA-21. For this purpose, in the first step, mass production of the Au/Pt bimetallic tubular micromotor was performed with a simple membrane template electrodeposition. The motions of catalytic Au/Pt micromotors in peroxide fuel media were analyzed under the SAW field effect. The changes in the micromotor speed were investigated depending on the type and concentration of surfactants in the presence and absence of SAW streaming. Our detection strategy was based on immobilization of probe dye-labeled single-stranded probe DNA (6-carboxyfluorescein dye-labeled-single-stranded DNA) to Au/Pt micromotors that recognize target miRNA-21. Before/after hybridization of miRNA-21 (for both w/o SAW and SAW streaming conditions), the changes in the speed of micromotors and their fluorescence intensities were studied. The response of fluorescence intensities was observed to be linearly varied with the increase of the miRNA-21 concentration from 0.5 to 5 nM under both w/o SAW and with SAW. The resulting fluorescence sensor showed a limit of detection of 0.19 nM, more than 2 folds lower compared to w/o SAW conditions. Thus, the sensor and behaviors of Au/Pt tubular micromotors were improved by acoustic removal systems.

Biodegradability of Micro/Nanomotors: Challenges and Opportunities

Micro/nanomotors (MNMs) are miniature machines that can convert chemical or external energy into their own mechanical motions. In previous decades, significant efforts have been made to improve the performance of MNMs. For practical applications, the biodegradability of MNMs is an important aspect that must be considered, particularly in the biomedical field. In this review, recent progress in the biodegradability of MNMs and their potential applications are summarized. Different biodegradable materials, including metals and polymers, or other strategies for the fabrication of MNMs, are presented. Current challenges and future perspectives are also discussed.

Current status of micro/nanomotors in drug delivery

Synthetic micro/nanomotors (MNMs) are novel, self-propelled nano or microscale devices that are widely used in drug transport, cell stimulation and isolation, bio-imaging, diagnostic and monitoring, sensing, photocatalysis and environmental remediation. Various preparation methods and propulsion mechanisms make MNMs "tailormade" nanosystems for the intended purpose or use. As the one of the newest members of nano carriers, MNMs open a new perspective especially for rapid drug transport and gene delivery. Although there exists limited number of in-vivo studies for drug delivery purposes, existence of in-vitro supportive data strongly encourages researchers to move on in this field and benefit from the manoeuvre capability of these novel systems. In this article, we reviewed the preparation and propulsion mechanisms of nanomotors in various fields with special attention to drug delivery systems.

Validation of Nanoparticle Response to the Sound Pressure Effect during the Drug-Delivery Process

Intravenous delivery is the fastest conventional method of delivering drugs to their targets in seconds, whereas intramuscular and subcutaneous injections provide a slower continuous delivery of drugs. In recent years, nanoparticle-based drug-delivery systems have gained considerable attention. During the progression of nanoparticles into the blood, the sound waves generated by the particles create acoustic pressure that affects the movement of nanoparticles. To overcome this issue, the impact of sound pressure levels on the development of nanoparticles was studied herein. In addition, a composite nanostructure was developed using different types of nanoscale substances to overcome the effect of sound pressure levels in the drug-delivery process. The results demonstrate the efficacy of the proposed nanostructure based on a group of different nanoparticles. This study suggests five materials, namely, polyimide, acrylic plastic, Aluminum 3003-H18, Magnesium AZ31B, and polysilicon for the design of the proposed structure. The best results were obtained in the case of the movement of these molecules at lower frequencies. The performance of acrylic plastic is better than other materials; the sound pressure levels reached minimum values at frequencies of 1, 10, 20, and 60 nHz. Furthermore, an experimental setup was designed to validate the proposed idea using advanced biomedical imaging technologies. The experimental results demonstrate the possibilities of detecting, tracking, and evaluating the movement behaviors of nanoparticles. The experimental results also demonstrate that the lowest sound pressure levels were observed at lower frequency levels, thus proving the validity of the proposed computational model assumptions. The outcome of this study will pave the way to understand the interaction behaviors of nanoparticles with the surrounding biological environments, including the sound pressure effect, which could lead to the useof such an effect in facilitating directional and tactic movements of the micro- and nano-motors.