Carbon nanosphere-based fluorescence aptasensor for targeted detection of breast cancer cell MCF-7

A photoelectrochemical cytosensor based on a Bi2S3-MoS2 heterojunction-modified reduced oxide graphene honeycomb film for sensitive detection of circulating tumor cells

A novel photoelectrochemical (PEC) cytosensor for the ultrasensitive detection of circulating tumor cells (CTCs) was developed. The bio-inspired reduced graphene oxide (rGO) honeycomb film photoelectrode was fabricated via a "breath figure" method, followed by the self-assembly of a Bi2S3-MoS2 heterojunction. The resulting Bi2S3-MoS2 heterojunction-modified rGO honeycomb film was employed as a sensing matrix for the first time. Compared to the smooth rGO film, the significant enhanced photocurrent of the photoelectrode under visible light was attributed to its improved visible light absorption, increased surface area and enhanced separation efficiency of photo-generated electron-hole pairs, which met the requirements of the PEC sensor for detecting larger targets. By virtue of the photocurrent decrease due to the steric hindrance of MCF-7 cells, which were captured by an aptamer immobilized on the surface of the photoelectrode, a cytosensor for detecting CTCs was achieved, showing a wide linear range of 10-1 × 105 cells per mL and a low detection limit of 2 cells per mL. Furthermore, MCF-7 cells in human serum were determined by this PEC biosensor, exhibiting great potential in the clinical detection of CTCs.

A photoelectrochemical aptasensor based on double Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction for sensitive detection of circulating tumor cells

A novel photoelectrochemical (PEC) aptasensor based on a dual Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction for the ultrasensitive detection of circulating tumor cells (CTCs) was developed. The α-Fe2O3/MoS2/Bi2S3 nanocomposite was prepared via a step-by-step route, and the photoproduced electron/hole transfer path was speculated by conducting trapping experiments of reactive species. α-Fe2O3/MoS2/Bi2S3-modified electrodes exhibited greatly enhanced photocurrent under visible light due to the double Z-scheme charge transfer process, which met the requirement of the PEC sensor for detecting larger targets. After the aptamer was conjugated on the photoelectrode through chitosan (CS) and glutaraldehyde (GA), when MCF-7 cells were presented and captured, the photocurrent of the PEC biosensing system decreased due to steric hindrance. The current intensity had a linear relationship with the logarithm of MCF-7 cell concentration ranging from 10 to 1×105 cells mL-1, with a low detection limit of 3 cell mL-1 (S/N = 3). The dual Z-scheme α-Fe2O3/MoS2/Bi2S3 ternary heterojunction-modified PEC aptasensor exhibited high sensitivity and excellent specificity and stability. Additionally, MCF-7 cells in human serum were determined by this PEC aptasensor, exhibiting great potential as a promising tool for clinical detection.

Recent advances in nanomaterials-based optical sensors for detection of various biomarkers (inorganic species, organic and biomolecules)

This review briefly emphasizes the different detection approaches (electrochemical sensors, chemiluminescence, surface-enhanced Raman scattering), functional nanostructure materials (quantum dots, metal nanoparticles, metal nanoclusters, magnetic nanomaterials, metal oxide nanoparticles, polymer-based nanomaterials, and carbonaceous nanomaterials) and detection mechanisms. Further, this review emphasis on the integration of functional nanomaterials with optical spectroscopic techniques for the identification of various biomarkers (nucleic acids, glucose, uric acid, oxytocin, dopamine, ascorbic acid, bilirubin, spermine, serotonin, thiocyanate, Pb²⁺ , Cu²⁺ , Hg²⁺ , F^- , peptides, and cancer biomarkers (mucin 1, prostate specific antigen, carcinoembryonic antigen, CA15-3, human epidermal growth factor receptor 2, C-reactive protein, and interleukin-6). Analytical characteristics of nanomaterials-based optical sensors are summarized in Tables, providing the insights of nanomaterials-based optical sensors for biomarkers detection. Finally, the opportunities and challenges of nanomaterials-based optical analytical approaches for the detection of various biomarkers (inorganic, organic, biomolecules, peptides and proteins) are discussed.

Ultrasensitive Detection of MCF-7 Cells with a Carbon Nanotube-Based Optoelectronic-Pulse Sensor Framework

Biosensors are of vital significance for healthcare by supporting the management of infectious diseases for preventing pandemics and the diagnosis of life-threatening conditions such as cancer. However, the advancement of the field can be limited by low sensing accuracy. Here, we altered the bioelectrical signatures of the cells using carbon nanotubes (CNTs) via structural loosening effects. Using an alternating current (AC) pulse under light irradiation, we developed a photo-assisted AC pulse sensor based on CNTs to differentiate between healthy breast epithelial cells (MCF-10A) and luminal breast cancer cells (MCF-7) within a heterogeneous cell population. We observed a previously undemonstrated increase in current contrast for MCF-7 cells with CNTs compared to MCF-10A cells with CNTs under light exposure. Moreover, we obtained a detection limit of ∼1.5 × 10³ cells below a baseline of ∼1 × 10⁴ cells for existing electrical-based sensors for an adherent, heterogeneous cell population. All-atom molecular dynamics (MD) simulations reveal that interactions between the embedded CNT and cancer cell membranes result in a less rigid lipid bilayer structure, which can facilitate CNT translocation for enhancing current. This as-yet unconsidered cancer cell-specific method based on the unique optoelectrical properties of CNTs represents a strategy for unlocking the detection of a small population of cancer cells and provides a promising route for the early diagnosis, monitoring, and staging of cancer.

Aptamer-conjugated carbon-based nanomaterials for cancer and bacteria theranostics: A review

Aptamers are single-stranded oligonucleotides that link to various substrates with great affinity and selectivity, including small molecules, peptides, proteins, cells, and tissues. For this reason, they can be used as imaging agents for cancer imaging techniques. Multifunctional nanomaterials combined with imaging probes and drugs are promising cancer diagnosis and treatment candidates. On the other hand, carbon-based nanomaterials (CNMs), including such as fullerene, carbon nanotubes, carbon-based quantum dots, carbon nanohorns, graphene oxide and its derivatives carbon nanodots, and nanodiamonds, are sort of smart materials that can be used in a variety of theranostic applications, including photo-triggered therapies. The remarkable physical characteristics, functionalizable chemistry, biocompatibility, and optical properties of these nanoparticles have enabled their utilization in less-invasive therapies. The theranostic agents that emerged by combining aptamers with CNMs have opened a novel alternative for personified medicine of cancer, target-specific imaging, and label-free diagnosis of a broad range of cancers, as well as pathogens. Aptamer-functionalized CNMs have been used as nanovesicles for targeted delivery of anti-cancer agents (i.e., doxorubicin and 5-fluorouracil) to tumor sites. Furthermore, these CNMs conjugated with aptamers have shown great advantages over standard CNMs to sensitively detect Mycobacterium tuberculosis, Escherichia coli, staphylococcus aureus, Vibrio parahaemolyticus, Salmonella typhimurium, Pseudomonas aeruginosa, and Citrobacter freundii. Regrettably, CNMs can form compounds defined as NOAA (nano-objects, and their aggregates and agglomerates larger than 100 nm), that accumulate in the body and cause toxic effects. Surface modification and pretreatment with albumin avoid agglomeration and increase the dispersibility of CNMs, so it is needed to guarantee the desirable interactions between functionalized CNMs and blood plasma proteins. This preliminary review aimed to comprehensively discuss the features and uses of aptamer-conjugated CNMs to manage cancer and bacterial infections.

Properties and Applications of Graphene and Its Derivatives in Biosensors for Cancer Detection: A Comprehensive Review

Cancer is one of the deadliest diseases worldwide, and there is a critical need for diagnostic platforms for applications in early cancer detection. The diagnosis of cancer can be made by identifying abnormal cell characteristics such as functional changes, a number of vital proteins in the body, abnormal genetic mutations and structural changes, and so on. Identifying biomarker candidates such as DNA, RNA, mRNA, aptamers, metabolomic biomolecules, enzymes, and proteins is one of the most important challenges. In order to eliminate such challenges, emerging biomarkers can be identified by designing a suitable biosensor. One of the most powerful technologies in development is biosensor technology based on nanostructures. Recently, graphene and its derivatives have been used for diverse diagnostic and therapeutic approaches. Graphene-based biosensors have exhibited significant performance with excellent sensitivity, selectivity, stability, and a wide detection range. In this review, the principle of technology, advances, and challenges in graphene-based biosensors such as field-effect transistors (FET), fluorescence sensors, SPR biosensors, and electrochemical biosensors to detect different cancer cells is systematically discussed. Additionally, we provide an outlook on the properties, applications, and challenges of graphene and its derivatives, such as Graphene Oxide (GO), Reduced Graphene Oxide (RGO), and Graphene Quantum Dots (GQDs), in early cancer detection by nanobiosensors.

Nanocarbon Tracer and Areola Injection Site Are Superior in the Sentinel Lymph Node Biopsy Procedure for Breast Cancer

Background. Axillary lymph node (ALN) staging is the most effective method to evaluate the condition of patients with breast cancer, their choice of treatment options, and prognosis. The sentinel lymph node (SLN) status assessment is the key to sentinel lymph node biopsy (SLNB) in patients with breast cancer. The choice of tracer and tracer injection sites affects SLNB. Objective. This study mainly analyzes the best tracer for SLNB and the best choice of tracer injection site. Methods. A total of 165 breast cancer patients who underwent SLNB were selected and injected with methylene blue or 99mTc-labeled sodium phytate or nanocarbon 20 min before biopsy. The number of SLNs detected by different tracers in different injection sites such as peritumoral tissue (PT) and subareolar area (SA) was counted, and the sensitivity, specificity, and positive/negative prediction rates were recorded and compared. Results. The detection success rate, average detection number of SLNs, and detection accuracy of the nanocarbon tracer were higher than the other two. The detection sensitivity, specificity, and positive and negative prediction rates of nanocarbon for SLNB were also higher than those of the other two tracers. When comparing the performance of tracers in different injection sites, it was found that the detection of three tracers injected in the SA was better than the injection in the PT. Conclusion. For women with early-stage breast cancer, nanocarbon can be used as the preferred tracer for SLNB to determine the status of the patient’s ALNs, and the areola area can be used as the best injection site.

Ultrasensitive two-dimensional material-based MCF-7 cancer cell sensor driven by perturbation processes

Changes in lipid composition and structure during cell development can be markers for cell apoptosis or various diseases such as cancer. Although traditional fluorescence techniques utilising molecular probes have been studied, these methods are limited in studying these micro-changes as they require complex probe preparation and cannot be reused, making cell monitoring and detection challenging. Here, we developed a direct current (DC) resistance sensor based on two-dimensional (2D) molybdenum disulfide (MoS₂) nanosheets to enable cancer cell-specific detection dependent on micro-changes in the cancer cell membrane. Atomistic molecular dynamics (MD) simulations were used to study the interaction between 2D MoS₂ and cancer lipid bilayer systems, and revealed that previously unconsidered perturbations in the lipid bilayer can cause an increase in resistance. Under an applied DC sweep, we observed an increase in resistance when cancer cells were incubated with the nanosheets. Furthermore, a correlation was observed between the resistance and breast cancer epithelial cell (MCF-7) population, illustrating a cell population-dependent sensitivity of our method. Our method has a detection limit of ∼3 × 10³ cells, below a baseline of ∼1 × 10⁴ cells for the current state-of-the-art electrical-based biosensors using an adherent monolayer with homogenous cells. This combination of a unique 2D material and electrical resistance framework represents a promising approach for the early detection of cancerous cells and to reduce the risk of post-surgery cancer recurrence.

Applications of Aptamer-Bound Nanomaterials in Cancer Therapy

Cancer is still a major disease that threatens human life. Although traditional cancer treatment methods are widely used, they still have many disadvantages. Aptamers, owing to their small size, low toxicity, good specificity, and excellent biocompatibility, have been widely applied in biomedical areas. Therefore, the combination of nanomaterials with aptamers offers a new method for cancer treatment. First, we briefly introduce the situation of cancer treatment and aptamers. Then, we discuss the application of aptamers in breast cancer treatment, lung cancer treatment, and other cancer treatment methods. Finally, perspectives on challenges and future applications of aptamers in cancer therapy are discussed.

Photoelectrochemical assay for the detection of circulating tumor cells based on aptamer-Ag2S nanocrystals for signal amplification

In this work, we developed a photoelectrochemical assay for circulating tumor cells (CTCs) detection based on hexagonal carbon-nitrogen tubes (HCNT) as visible light-sensitive materials. The MCF-7 cell was selected as the model CTC and was captured through specific recognition between epithelial cell adhesion molecules (EpCAM) on the cell surface and anti-EpCAM antibodies. Anti-EpCAM antibody-modified magnetic nanoparticles were used to enrich and separate MCF-7 cells from samples. The detection signal was amplified by Ag₂S nanocrystals, which can compete with HCNTs for absorbing visible light, leading to a decrease of photocurrent intensity. The linear range of the assay for MCF-7 cells is from 10 to 5000 cells mL^-1, with a detection limit of 3 cells mL^-1 (S/D = 3). The assay has good selectivity for MCF-7 detection over HeLa cells. The assay was successfully applied for the detection of MCF-7 in human whole blood, which indicates the potential for clinical application.

Aptamer-based sensing of breast cancer biomarkers: a comprehensive review of analytical figures of merit

INTRODUCTION

Accurate determination of the aberrantly expressed biomarkers such as human epidermal growth factor receptor 2 (HER2), carcinoembryonic antigen (CEA), platelet-derived growth factor (PDGF), mucin 1 (MUC1), and vascular endothelial growth factor VEGF₁₆₅ have played an essential role in the clinical management of the breast cancer. Assessment of these cancer-specific biomarkers has conventionally relied on time-taking methods like the enzyme-linked immunosorbent assay and immunohistochemistry. However, recent development in the aptamer-based diagnostics has allowed developing tools that may substitute the conventional means of biomarker assessment in breast cancer. Adopting the aptamer-based diagnostic tools (aptasensors) to clinical practices will depend on their analytical performance on clinical samples.

AREAS COVERED

In this review, we provide an overview of the analytical merits of HER2, CEA, PDGF, MUC1, and VEGF₁₆₅ aptasensors. Scopus and Pubmed databases were searched for studies reporting aptasensor development for the listed breast cancer biomarkers in the past one decade. Linearity, detection limit, and response time are emphasized.

EXPERT OPINION

In our opinion, aptasensors have proven to be on a par with the antibody-based methods for detection of various breast cancer biomarkers. Though robust validation of the aptasensors on significant sample size is required, their ability to detect pathophysiological range of biomarkers suggest the possibility of future clinical adoption.

Multifunctional nanoparticles as optical biosensing probe for breast cancer detection: A review

Optical biosensors show attractive performance in medical sensing in the event of using different nanoparticles in their design. Owing to their unique optical characteristics and biological compatibility, gold nanoparticles (GNPs), silver nanoparticles (AgNPs), bimetallic nanoparticles and magnetic nanoparticles have been broadly implemented in making sensing tools. The functionalization of these nanoparticles with different components provides an excellent opportunity to assemble selective and sensitive sensing materials to detect various biological molecules related to breast cancer. This review summarizes the recent application of optical biosensing devices based on nanomaterials and discusses their pros and cons to improve breast cancer detection in real samples. In particular, the main constituent elements of these optical biosensors including recognition and transducer elements, types of applied nanostructures, analytical sensing procedures, sensor detection ranges and limit of detection (LOD), are expressed in detail.

Clinical Study of Ultrasonic Extreme Velocity Imaging Pulse Wave Technique in Carotid Elasticity in Patients with Type II Diabetes Mellitus

In this study, extreme velocity ultrasonic imaging pulse wave technology was used to detect the main indices of atherosclerosis such as carotid intima-media thickness (IMT) and carotid elasticity, and biochemical indices such as glycated hemoglobin, blood glucose and blood lipids in one hundred twenty 18–60-year-old patients with type II diabetes mellitus (T2DM) and 120 healthy controls. We analyzed the correlations between carotid elasticity, carotid IMT, and a range of biochemical indices. The results indicated that when the carotid IMT in young and middle-aged patients with T2DM was within the normal range (0.56±0.03 mm), the carotid artery elasticity was abnormal [Pulse wave propagation velocity (PWV)-BS = 7.69± 1.26 m/s; PWV-ES = 8.34±1.51 m/s; P < 0.05]. Additionally, PWV-BS was positively correlated with age, course of the disease, glycated hemoglobin (HbA1c), and fasting blood glucose (FBG) (r = 0.297, 0.377, 0.369, 0.382), and PWV-ES was positively correlated with age, course of the disease, HbA1c, and FBG (r = 0.318, 0.386, 0.392, 0.339). This finding provides a basis for extreme velocity ultrasonic imaging pulse wave technology to become a new method for the early screening of atherosclerosis in patients with T2DM; this is important for timely clinical intervention in patients with T2DM.

Point-of-care diagnostics for infectious diseases: From methods to devices

The current widespread of COVID-19 all over the world, which is caused by SARS-CoV-2 virus, has again emphasized the importance of development of point-of-care (POC) diagnostics for timely prevention and control of the pandemic. Compared with labor- and time-consuming traditional diagnostic methods, POC diagnostics exhibit several advantages such as faster diagnostic speed, better sensitivity and specificity, lower cost, higher efficiency and ability of on-site detection. To achieve POC diagnostics, developing POC detection methods and correlated POC devices is the key and should be given top priority. The fast development of microfluidics, micro electro-mechanical systems (MEMS) technology, nanotechnology and materials science, have benefited the production of a series of portable, miniaturized, low cost and highly integrated POC devices for POC diagnostics of various infectious diseases. In this review, various POC detection methods for the diagnosis of infectious diseases, including electrochemical biosensors, fluorescence biosensors, surface-enhanced Raman scattering (SERS)-based biosensors, colorimetric biosensors, chemiluminiscence biosensors, surface plasmon resonance (SPR)-based biosensors, and magnetic biosensors, were first summarized. Then, recent progresses in the development of POC devices including lab-on-a-chip (LOC) devices, lab-on-a-disc (LOAD) devices, microfluidic paper-based analytical devices (μPADs), lateral flow devices, miniaturized PCR devices, and isothermal nucleic acid amplification (INAA) devices, were systematically discussed. Finally, the challenges and future perspectives for the design and development of POC detection methods and correlated devices were presented. The ultimate goal of this review is to provide new insights and directions for the future development of POC diagnostics for the management of infectious diseases and contribute to the prevention and control of infectious pandemics like COVID-19.

Aptamer based recognition of cancer cells: Recent progress and challenges in bioanalysis

Rapid and accurate monitoring of cancer cells with high sensitivity is essential for a successful cancer treatment. As high-affinity nucleic acid ligands, aptamers can improve the properties of detection methods by conjugating with intracellular or extracellular cancer biomarkers. Despite the advances in the early detection and treatment of cancer cells, lacking effective early detection tools is one of the causes of a high mortality rate. Aptasensors, which are based on the specificity of aptamer-target recognition, with transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. In this review, some selective and sensitive methods were summarized based on advanced nanomaterials towards aptasensing of cancer cells, such as blood, breast, cervical, colon, gastric, liver, and lung cancer cells. This review summarizes advances from 2010 to June 2020 in the development of aptasensors for cancer cell detection. Various aptasensing strategies are assessed according to their potential for reaching relevant limits of sensitivity, specificity, and degrees of multiplexing. Furthermore, we address the remaining challenges and opportunities to integrate aptasensing platforms into point-of-care solutions. Finally, the advantages and limitations of aptamer-based aptasensing strategies were reviewed.

A review: Recent advances in ultrasensitive and highly specific recognition aptasensors with various detection strategies

One of the most studied topics in analytical chemistry and physics is to develop bio-sensors. Aptamers are small single-stranded RNA or DNA oligonucleotides (5-25 kDa), which have advantages in comparison to their antibodies such as physicochemical stability and high binding specificity. They are able to integrate with proteins or small molecules, including intact viral particles, plant lectins, gene-regulation factor, growth factors, antibodies and enzymes. The aptamers have reportedly shown some unique characteristics, including long shelf-life, simple modification to provide covalent bonds to material surfaces, minor batch variation, cost-effectiveness and slight denaturation susceptibility. These features led important efforts toward the development of aptamer-based sensors, known as apta-sensors classified into optical, electrical and mass-sensitive based on the signal transduction mode. This review provided a number of current advancements in selecting, development criteria, and aptamers application with the focus on the effect of apta-sensors, specifically for disease-associated analyses. The review concentrated on the current reports of apta-sensors that are used for evaluating different food and environmental pollutants.

Controlled assembly of AIEgens based on a super-quadruplex scaffold for detection of plasma membrane proteins

Quantification of plasma membrane proteins (PMPs) is crucial for understanding the fundamentals of cellular signaling systems and their related diseases. In this work, a super-quadruplex scaffold was designed to regulate assembly of oligonucleotide-grafted AIEgens for detection of PMPs. The nonfluorescence oligonucleotide-grafted AIEgen (Oligo-AIEgen) was firstly synthesized by attaching the AIEgen to 3'-terminus of the oligonucleotide through click chemistry. Meanwhile, the tetramolecular hairpin-conjugated super-quadruplex (THP-G4) as cleavage element and signal enhancement scaffold composited of three elements: a substrate sequence of DNAzyme in the loop region, partial hybridization region in the stem, and six guanine nucleotides to form G-quadruplex. Once the DNAzyme was anchored on the specific PMPs through aptamer-protein recognition, the substrate sequence on the loop of THP-G4 was cleaved by DNAzyme with the aid of cofactor Mn^II, resulting in the conformation switch of THP-G4 to the activated G-quadruplex scaffold. The latter could assemble Oligo-AIEgens to generate aggregation-induced emission (AIE) enhancement, resulting in a simple and sensitive strategy for detection of membrane proteins. Moreover, the DNAzyme continuously cut the next THP-G4 to achieve recycling amplification. Under the optimized conditions, this AIE-based strategy exhibited good linear relationship with the logarithm of MUC1 concentration from 0.01 to 10 μg mL^-1 with the limit of detection down to 4.3 ng mL^-1. The G4-assembled AIEgens provides a universal platform for detecting various biomolecules and a proof-of concept for AIE biosensing.

An exonuclease-assisted triple-amplified electrochemical aptasensor for mucin 1 detection based on strand displacement reaction and enzyme catalytic strategy

The development of some sensitive methods for MUC1 is critical for preclinical diagnosis of tumors. In this experiment, we built a triple-amplified electrochemical aptasensor to achieve sensitive detection of MUC1, which was based on exonuclease III (Exo III)-assisted with strand displacement reaction and enzyme catalytic strategy. Firstly, with the help of Exo III, MUC1 and aptamer could be recycled during the cycle I, the single stranded DNA-1 (S-1) was produced during the process and was introduced to the hybride reaction on the electrode. Secondly, during the cycle II, strand displacement reaction was triggered on the electrode with the adding of hairpin DNA-2 (H-2). Thirdly, after the gold nanoparticles (AuNPs)-DNA-enzyme conjugates hybrided with the H-2 on the electrode, the AuNPs-DNA-enzyme conjugates could act as signal probe to produce electrochemical catalytic signal. We used the fabricated triple-amplified electrochemical aptasensor that could detect MUC1 from 0.1 pg mL^-1 to 10 ng mL^-1 with the detection limit of 0.04 pg mL^-1 under the optimized experimental conditions. The constructed triple-amplified electrochemical aptasensor could be applied in real samples determination. Besides, the strategy can be applied to detect other proteins for health monitoring.

DNA-Based Nanomedicine with Targeting and Enhancement of Therapeutic Efficacy of Breast Cancer Cells

Recently, a DNA tetrahedron has been reported to be a novel nanomedicine and promising drug vector because of its compactness, biocompatibility, biosafety, and editability. Here, we modified the DNA tetrahedron with a DNA aptamer (AS1411) as a DNA-based delivery system, which could bind to nucleolin for its cancer cell selectivity. Nucleolin is a specific biomarker protein overexpressed on membranes of malignant cancer cells and its deregulation is implicated in cell proliferation. The antimetabolite drug 5-fluorouracil (5-FU) is an extensively used anticancer agent; however, its major limitation is the lack of target specificity. Cyanine 5 (Cy5), a fluorescent probe, can be used to label DNA tetrahedron and enhance photostability with minimal effects on its basic functions. In this study, we additionally attached 5-FU to the DNA-based delivery system as a new tumor-targeting nanomedicine (AS1411-T-5-FU) to enhance the therapeutic efficacy and targeting of breast cancer. We examined the difference of the cellular uptake of AS1411-T-5-FU between breast cancer cells and normal breast cells and concluded that AS1411-T-5-FU had a better targeting ability to kill breast cancer cells than 5-FU. We further evaluated the expressions of cell apoptosis-related proteins and genes, which are associated with the mitochondrial apoptotic pathway. Ultimately, our results suggest the potential of DNA tetrahedron in cancer therapies, and we develop a novel approach to endow 5-FU with targeting property.

Aptasensors as a new sensing technology developed for the detection of MUC1 mucin: A review

Mucin 1 protein (MUC1) is a membrane-associated glycoprotein overexpressed in the majority of human malignancies and considered as a predominant protein biomarker in cancers. Owing to the crucial role of MUC1 in cancer dissemination and metastasis, detection and quantification of this biomarker is of great importance in clinical diagnostics. Today, there exist a wide variety of strategies for the determination of various types of disease biomarkers, especially MUC1. In this regard, aptamers, as artificial single-stranded DNA or RNA oligonucleotides with catalytic and receptor properties, have drawn lots of attention for the development of biosensing platforms. So far, various sensitivity-enhancement techniques in combination with a broad range of smart nanomaterials have integrated into the design of novel aptamer-based biosensors (aptasensors) to improve detection limit and sensitivity of analyte determination. This review article provides a brief classification and description of the research progresses of aptamer-based biosensors and nanobiosensors for the detection and quantitative determination of MUC1 based on optical and electrochemical platforms.