Aptamer-conjugated graphene oxide membranes for highly efficient capture and accurate identification of multiple types of circulating tumor cells

Recent advances of biocompatible optical nanobiosensors in liquid biopsy: towards early non-invasive diagnosis

Liquid biopsy is a non-invasive diagnostic method that can reduce the risk of complications and offers exceptional benefits in the dynamic monitoring and acquisition of heterogeneous cell population information. Optical nanomaterials with excellent light absorption, luminescence, and photoelectrochemical properties have accelerated the development of liquid biopsy technologies. Owing to the unique size effect of optical nanomaterials, their improved optical properties enable them to exhibit good sensitivity and specificity for mitigating signal interference from various molecules in body fluids. Nanomaterials with biocompatible and optical sensing properties play a crucial role in advancing the maturity and diversification of liquid biopsy technologies. This article offers a comprehensive review of recent advanced liquid biopsy technologies that utilize novel biocompatible optical nanomaterials, including fluorescence, colorimetric, photoelectrochemical, and Raman broad-spectrum-based biosensors. We focused on liquid biopsy for the most significant early biomarkers in clinical medicine, and specifically reviewed reports on the effectiveness of optical nanosensing technology in the detection of real patient samples, which may provide basic evidence for the transition of optical nanosensing technology from engineering design to clinical practice. Furthermore, we introduced the integration of optical nanosensing-based liquid biopsy with modern devices, such as smartphones, to demonstrate the potential of the technology in portable clinical diagnosis.

Construction of Smart DNA-Based Drug Delivery Systems for Cancer Therapy

Due to the disadvantages of poor targeting, slow action, and low effectiveness of current commonly used cancer treatments, including surgery, chemotherapy, and radiotherapy, researchers have turned to DNA as a biomaterial for constructing drug delivery nanocarriers. DNA is favored for its biocompatibility and programmability. In order to overcome the limitations associated with traditional drug delivery systems (DDSs), researchers have developed smart-responsive DNA DDSs that can control drug release in response to specific physical or chemical stimuli at targeted sites. In this review, a summary of multiple targeted ligand structures is provided, various shapes of stable DNA nanomaterials, and different stimuli-responsive drug release strategies in DNA DDSs. Specifically, targeted cell recognition, in vivo stable transport, and controlled drug release of smart DDSs are focused. Finally, the further development prospects and challenges of clinical application of DNA nanomaterials in the field of smart drug delivery are discussed. The objective of this review is to enhance researchers' comprehension regarding the potential application of DNA nanomaterials in precision drug delivery, with the aim of expediting the clinical implementation of intelligent DDSs.

The Landscape of Biomimetic Nanovesicles in Brain Diseases

Brain diseases, such as brain tumors, neurodegenerative diseases, cerebrovascular diseases, and brain injuries, are caused by various pathophysiological changes, which pose a serious health threat. Brain disorders are often difficult to treat due to the presence of the blood-brain barrier (BBB). Biomimetic nanovesicles (BNVs), including endogenous extracellular vesicles (EVs) derived from various cells and artificial nanovesicles, possess the ability to penetrate the BBB and thus can be utilized for drug delivery to the brain. BNVs, especially endogenous EVs, are widely distributed in body fluids and usually carry various disease-related signal molecules such as proteins, RNA, and DNA, and may also be analyzed to understand the etiology and pathogenesis of brain diseases. This review covers the exhaustive classification and characterization of BNVs and pathophysiological roles involved in various brain diseases, and emphatically focuses on nanotechnology-integrated BNVs for brain disease theranostics, including various diagnosis strategies and precise therapeutic regulations (e.g., immunity regulation, disordered protein clearance, anti-neuroinflammation, neuroregeneration, angiogenesis, and the gut-brain axis regulation). The remaining challenges and future perspectives regarding the nanotechnology-integrated BNVs for the diagnosis and treatment of brain diseases are also discussed and outlined.

Efficient detection of single circulating tumor cell in blood using Raman mapping based on Aptamer-SERS bio-probe coupled with micropore membrane filtration

Rapid and accurate detection of rare circulating tumor cells (CTCs) in human blood still remains a challenge. We present a surface enhanced Raman spectroscopy (SERS) method based on aptamer-SERS bio-probe recognition coupled with micropore membrane filtration capture for the detection of CTCs at single cell level. The parylene micropore membrane with optimized micropore size installed on a filtration holder could capture bio-probe labeled CTCs by gravity in less than 10 s, and only with very less white blood cells (WBCs) residual. In order to facilitate the synthesis of the aptamer-SERS bio-probe, ethyl acetate dehydration method was established. The bio-probe can be rapidly synthesized within 2 h by binding SH-aptamer to 4- mercaptobenzoic acid (4-MBA) modified AuNPs with the help of ethyl acetate. The SERS bio-probe with selected specific aptamer could distinguish single human non-small cell lung cancer A549 cells from residual WBCs on membrane efficiently and reliably based on their Raman signal intensity difference at 1075 cm-1. Through the filter membrane coupled with aptamer-SERS bio-probe system, even 20 A549 cells in blood solution simulating CTCs sample can be detected, which the recovery rate and recognition rate are more than 90%. This method is rapid, reliable and cost-effective, which indicates a good prospect in clinical application for CTCs detection.

Graphene oxide nanoarchitectures in cancer therapy: Drug and gene delivery, phototherapy, immunotherapy, and vaccine development

The latest advancements in oncology involves the creation of multifunctional nanostructures. The integration of nanoparticles into the realm of cancer therapy has brought about a transformative shift, revolutionizing the approach to addressing existing challenges and limitations in tumor elimination. This is particularly crucial in combating the emergence of resistance, which has significantly undermined the effectiveness of treatments like chemotherapy and radiotherapy. GO stands as a carbon-derived nanoparticle that is increasingly finding utility across diverse domains, notably in the realm of biomedicine. The utilization of GO nanostructures holds promise in the arena of oncology, enabling precise transportation of drugs and genetic material to targeted sites. GO nanomaterials offer the opportunity to enhance the pharmacokinetic behavior and bioavailability of drugs, with documented instances of these nanocarriers elevating drug accumulation at the tumor location. The GO nanostructures encapsulate genes, shielding them from degradation and facilitating their uptake within cancer cells, thereby promoting efficient gene silencing. The capability of GO to facilitate phototherapy has led to notable advancements in reducing tumor progression. By PDT and PTT combination, GO nanomaterials hold the capacity to diminish tumorigenesis. GO nanomaterials have the potential to trigger both cellular and innate immunity, making them promising contenders for vaccine development. Additionally, types of GO nanoparticles that respond to specific stimuli have been applied in cancer eradication, as well as for the purpose of cancer detection and biomarker diagnosis. Endocytosis serves as the mechanism through which GO nanomaterials are internalized. Given these advantages, the utilization of GO nanomaterials for tumor elimination comes highly recommended.

Unlocking Translational Potential: Conditionally Reprogrammed Cells in Advancing Breast Cancer Research

Preclinical in vitro models play an important role in studying cancer cell biology and facilitating translational research, especially in the identification of drug targets and drug discovery studies. This is particularly relevant in breast cancer, where the global burden of disease is quite high based on prevalence and a relatively high rate of lethality. Predictive tools to select patients who will be responsive to invasive or morbid therapies (radiotherapy, chemotherapy, immunotherapy, and/or surgery) are relatively lacking. To be clinically relevant, a model must accurately replicate the biology and cellular heterogeneity of the primary tumor. Addressing these requirements and overcoming the limitations of most existing cancer cell lines, which are typically derived from a single clone, we have recently developed conditional reprogramming (CR) technology. The CR technology refers to a co-culture system of primary human normal or tumor cells with irradiated murine fibroblasts in the presence of a Rho-associated kinase inhibitor to allow the primary cells to acquire stem cell properties and the ability to proliferate indefinitely in vitro without any exogenous gene or viral transfection. This innovative approach fulfills many of these needs and offers an alternative that surpasses the deficiencies associated with traditional cancer cell lines. These CR cells (CRCs) can be reprogrammed to maintain a highly proliferative state and reproduce the genomic and histological characteristics of the parental tissue. Therefore, CR technology may be a clinically relevant model to test and predict drug sensitivity, conduct gene profile analysis and xenograft research, and undertake personalized medicine. This review discusses studies that have applied CR technology to conduct breast cancer research.

Biosensing Systems Based on Graphene Oxide Fluorescence Quenching Effect

Graphene oxide (GO) is a versatile material obtained by the strong oxidation of graphite. Among its peculiar properties, there is the outstanding ability to significantly alter the fluorescence of many common fluorophores and dyes. This property has been exploited in the design of novel switch-ON and switch-OFF fluorescence biosensing platforms for the detection of a plethora of biomolecules, especially pathological biomarkers and environmental contaminants. Currently, novel advanced strategies are being developed for therapeutic, diagnostic and theranostic approaches to widespread pathologies caused by viral or bacterial agents, as well as to cancer. This work illustrates an overview of the most recent applications of GO-based sensing systems relying on its fluorescence quenching effect.

Double spiral chip-embedded micro-trapezoid filters (SMT filters) for the sensitive isolation of CTCs of prostate cancer by spectral detection

Circulating tumor cells (CTCs) are cancer cells that are released from the original tumor and circulate in the blood vessels, carrying greatly similar constituents as the original tumor. Therefore, CTCs have a significant value in cancer prognosis, early diagnosis, and anti-cancer therapy. However, their rarity and heterogeneity make the isolation of CTCs an arduous task. In the present research, we propose a double spiral chip-embedded micro-trapezoid filter (SMT filter) for the sensitive isolation of the CTCs of prostate cancer by spectral detection. SMT filters were elongated to effectively capture CTCs and this distinctive design was conducive to their isolation and enrichment. The SMT filters were verified with tumor cells and artificial patient blood with a capture efficiency as high as 94% at a flow rate of 1.5 mL h^-1. As a further validation, the SMT filters were validated in isolating CTCs from 10 prostate cancers and other cancers in 4 mL blood samples. Also, the CTCs tested positive for each patient blood sample, ranging from 83-114 CTCs. Significantly, we advanced hyperspectral imaging to detect the characteristic spectrum of CTCs both captured in situ on SMT filters and enriched after isolation. The CTCs could be positively identified by hyperspectral imaging with complete integrity of the cell morphology and an improved characteristic spectrum. This represents a breakthrough in the conventional surface-enhanced Raman scattering (SERS) spectroscopy of nanoparticles. Also, the characteristic spectrum of the CTCs would be highly beneficial for distinguishing the cancer type and accurate for enumerating tumor cells with varied intensities. Furthermore, a novel integrated flower-shaped microfilter was presented with all these aforementioned merits. The success of both the SMT filters and characteristic spectral detection indicated their feasibility for further clinical analysis, the evaluation of cancer therapy, and for potential application.

Bioconjugated Nanomaterial for Targeted Diagnosis of SARS-CoV-2

Infectious diseases by pathogenic microorganisms are one of the leading causes of mortality worldwide. Healthcare and socio-economic development have been seriously affected for different civilizations because of bacterial and viral infections. According to the Centers for Disease Control and Prevention (CDC), pandemic in 1918 by the Influenza A virus of the H1N1 subtype was responsible for 50 to 100 million deaths worldwide. Similarly, the Asian flu pandemic in 1957, Hong Kong flu in 1968, and H1N1pdm09 flu pandemic in 2009 were responsible for more than 1 million deaths across the globe each time. As per the World Health Organization (WHO), the current pandemic by coronavirus disease 2019 (COVID-19) due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is responsible for more than 4.8 M death worldwide until now. Since the gold standard polymerase chain reaction (PCR) test is more time-consuming, the health care system cannot test all symptomatic and asymptomatic Covid patients every day, which is extremely important to tackle the outbreak. One of the significant challenges during the current pandemic is developing mass testing tools, which is critical to control the virus spread in the community. Therefore, it is highly desirable to develop advanced material-based approaches that can provide a rapid and accurate diagnosis of COVID-19, which will have the capability to save millions of human lives. Aiming for the targeted diagnosis of deadly virus, researchers have developed nanomaterials with various sizes, shapes, and dimensions. These nanomaterials have been used to identify biomolecules via unique optical, electrical, magnetic, structural, and functional properties, which are lacking in other materials. Despite significant progress, nanomaterial-based diagnosis of biomolecules is still facing several obstacles due to low targeting efficiency and nonspecific interactions. To overcome these problems, the bioconjugated nanoparticle has been designed via surface coating with polyethylene glycol (PEG) and then conjugated with antibodies, DNA, RNA, or peptide aptamers. Therefore, the current Account summarizes an overview of the recent advances in the design of bioconjugated nanomaterial-based approached as effective diagnosis of the SARS-CoV-2 virus and the SARS-CoV-2 viral RNA, antigen, or antibody, with a particular focus on our work and other's work related to this subject. First, we present how to tailor the surface functionalities of nanomaterials to achieve bioconjugated material for targeted diagnosis of the virus. Then we review the very recent advances in the design of antibody/aptamer/peptide conjugated nanostructure, which represent a powerful platform for naked-eye colorimetric detection via plasmonic nanoparticles. We then discuss nanomaterial-based surface-enhanced Raman scattering (SERS) spectroscopy, which has the capability for very low-level fingerprint identification of virus, antigen, and antibody via graphene, plasmonic nanoparticle, and heterostructure material. After that, we summarized about fluorescence and nanoparticle surface energy transfer (NSET)-based on specific identification of SARS-CoV-2 infections via CNT, quantum dots (QDs), and plasmonic nanoparticles. Finally, we highlight the merit and significant challenges of nanostructure-based tools in infectious diseases diagnosis. For the researchers who want to engage in the new development of bioconjugated material for our survival from the current and future pandemics, we hope that this Account will be helpful for generating ideas that are scientifically stimulating and practically challenging.

Graphene Based Nanohybrid Aptasensors in Environmental Monitoring: Concepts, Design and Future Outlook

In view of ever-increasing environmental pollution, there is an immediate requirement to promote cheap, multiplexed, sensitive and fast biosensing systems to monitor these pollutants or contaminants. Aptamers have shown numerous advantages in being used as molecular recognition elements in various biosensing devices. Graphene and graphene-based materials/nanohybrids combined with several detection methods exhibit great potential owing to their exceptional optical, electronic and physicochemical properties which can be employed extensively to monitor environmental contaminants. For environmental monitoring applications, aptamers have been successfully combined with graphene-based nanohybrids to produce a wide range of innovative methodologies. Aptamers are immobilized at the surface of graphene based nanohybrids via covalent and non-covalent strategies. This review highlights the design, working principle, recent developmental advances and applications of graphene based nanohybrid aptasensors (GNH-Apts) (since January 2014 to September 2021) with a special emphasis on two major signal-transduction methods, i.e., optical and electrochemical for the monitoring of pesticides, heavy metals, bacteria, antibiotics, and organic compounds from different environmental samples (e.g., water, soil and related). Lastly, the challenges confronted by scientists and the possible future outlook have also been addressed. It is expected that high-performance graphene-based nanohybrid aptasensors would find broad applications in the field of environmental monitoring.

Recent Advances in Aptamer-Based Liquid Biopsy

Liquid biopsy capable of noninvasive and real-time molecular profiling is considered as a breakthrough technology, endowing an opportunity for precise diagnosis of individual patients. Extracellular vesicles (EVs) and circulating tumor cells (CTCs) consisting of substantial disease-related molecular information play an important role in liquid biopsy. Therefore, it is critically significant to exploit high-performance recognition ligands for efficient isolation and analysis of EVs and CTCs from complex body fluids. Aptamers exhibit extraordinary merits of high specificity and affinity, which are considered as superior recognition ligands for liquid biopsy. In this review, we first summarize recent advanced strategies for the evolution of high-performance aptamers and the construction of various aptamer-based recognition elements. Subsequently, we mainly discuss the isolation and analysis of EVs and CTCs based on the aptamer functioned biomaterials/biointerface. Ultimately, we envision major challenges and future direction of aptamer-based liquid biopsy for clinical utilities.

A review of enrichment methods for circulating tumor cells: from single modality to hybrid modality

Circulating tumor cell (CTC) analysis as a liquid biopsy can be used for early diagnosis of cancer, evaluating cancer progression, and assessing treatment efficacy. The enrichment of CTCs from patient blood is important for CTC analysis due to the extreme rarity of CTCs. This paper updates recent advances in CTC enrichment methods. We first review single-modality methods, including biophysical and biochemical methods. Hybrid-modality methods, combining at least two single-modality methods, are gaining increasing popularity for their improved performance. Then this paper reviews hybrid-modality methods, which are categorized into integrated and sequenced hybrid-modality methods. The state of the art indicates that the CTC capture efficiencies of integrated hybrid-modality methods can reach 85% or higher by taking advantage of the superimposed and enhanced capture effects from multiple single-modality methods. Moreover, a hybrid method integrating biophysical with biochemical methods is characterized by both high processing rate and high specificity.

Identification and Engineering of Aptamers for Theranostic Application in Human Health and Disorders

An aptamer is a short sequence of synthetic oligonucleotides which bind to their cognate target, specifically while maintaining similar or higher sensitivity compared to an antibody. The in-vitro selection of an aptamer, applying a conjoining approach of chemistry and molecular biology, is referred as Systematic Evolution of Ligands by Exponential enrichment (SELEX). These initial products of SELEX are further modified chemically in an attempt to make them stable in biofluid, avoiding nuclease digestion and renal clearance. While the modification is incorporated, enough care should be taken to maintain its sensitivity and specificity. These modifications and several improvisations have widened the window frame of aptamer applications that are currently not only restricted to in-vitro systems, but have also been used in molecular imaging for disease pathology and treatment. In the food industry, it has been used as sensor for detection of different diseases and fungal infections. In this review, we have discussed a brief history of its journey, along with applications where its role as a therapeutic plus diagnostic (theranostic) tool has been demonstrated. We have also highlighted the potential aptamer-mediated strategies for molecular targeting of COVID-19. Finally, the review focused on its future prospective in immunotherapy, as well as in identification of novel biomarkers in stem cells and also in single cell proteomics (scProteomics) to study intra or inter-tumor heterogeneity at the protein level. Small size, chemical synthesis, low batch variation, cost effectiveness, long shelf life and low immunogenicity provide advantages to the aptamer over the antibody. These physical and chemical properties of aptamers render them as a strong biomedical tool for theranostic purposes over the existing ones. The significance of aptamers in human health was the key finding of this review.

Recent Development of Nanomaterials-Based Cytosensors for the Detection of Circulating Tumor Cells

The accurate analysis of circulating tumor cells (CTCs) holds great promise in early diagnosis and prognosis of cancers. However, the extremely low abundance of CTCs in peripheral blood samples limits the practical utility of the traditional methods for CTCs detection. Thus, novel and powerful strategies have been proposed for sensitive detection of CTCs. In particular, nanomaterials with exceptional physical and chemical properties have been used to fabricate cytosensors for amplifying the signal and enhancing the sensitivity. In this review, we summarize the recent development of nanomaterials-based optical and electrochemical analytical techniques for CTCs detection, including fluorescence, colorimetry, surface-enhanced Raman scattering, chemiluminescence, electrochemistry, electrochemiluminescence, photoelectrochemistry and so on.

Aptamer-based nanostructured interfaces for the detection and release of circulating tumor cells

Analysis of circulating tumor cells (CTCs) can provide significant clinical information for tumors, which has proven to be helpful for cancer diagnosis, prognosis monitoring, treatment efficacy, and personalized therapy. However, CTCs are an extremely rare cell population, which challenges the isolation of CTCs from patient blood. Over the last few decades, many strategies for CTC detection have been developed based on the physical and biological properties of CTCs. Among them, nanostructured interfaces have been widely applied as CTC detection platforms to overcome the current limitations associated with CTC capture. Furthermore, aptamers have attracted significant attention in the detection of CTCs due to their advantages, including good affinity, low cost, easy modification, excellent stability, and low immunogenicity. In addition, effective and nondestructive release of CTCs can be achieved by aptamer-mediated methods that are used under mild conditions. Herein, we review some progress in the detection and release of CTCs through aptamer-functionalized nanostructured interfaces.

Aptamer-Based Detection of Circulating Targets for Precision Medicine

The past decade has witnessed ongoing progress in precision medicine to improve human health. As an emerging diagnostic technique, liquid biopsy can provide real-time, comprehensive, dynamic physiological and pathological information in a noninvasive manner, opening a new window for precision medicine. Liquid biopsy depends on the sensitive and reliable detection of circulating targets (e.g., cells, extracellular vesicles, proteins, microRNAs) from body fluids, the performance of which is largely governed by recognition ligands. Aptamers are single-stranded functional oligonucleotides, capable of folding into unique tertiary structures to bind to their targets with superior specificity and affinity. Their mature evolution procedure, facile modification, and affinity regulation, as well as versatile structural design and engineering, make aptamers ideal recognition ligands for liquid biopsy. In this review, we present a broad overview of aptamer-based liquid biopsy techniques for precision medicine. We begin with recent advances in aptamer selection, followed by a summary of state-of-the-art strategies for multivalent aptamer assembly and aptamer interface modification. We will further describe aptamer-based micro-/nanoisolation platforms, aptamer-enabled release methods, and aptamer-assisted signal amplification and detection strategies. Finally, we present our perspectives regarding the opportunities and challenges of aptamer-based liquid biopsy for precision medicine.

Coordination-driven reversible surfaces with site-specifically immobilized nanobody for dynamic cancer cell capture and release

Selective isolation of circulating tumor cells (CTCs) from blood provides a non-invasive avenue for the diagnosis, prognosis and personalized treatment for patients with cancer. The specific capture of CTCs is conventionally based on the immunoaffinity recognition between antibody and receptor on cell membranes. However, using a traditional antibody for high-efficiency isolation of CTCs remains a challenge due to the limited loading capacity of the large antibodies on material surfaces. Herein, using a small-sized nanobody (Nb), we developed a widely applicable strategy to construct reversible site-specifically immobilized Nb surfaces for the capture and release of epidermoid cancer cell line A431 cells. Coordination interaction between the histidine tag (His-tag) of the nanobody (Nb) and Ni2+ ions that chelated to the NTA-modified poly(2-hydroxyethyl methacrylate) (PHEMA) brushes was used to achieve site-specific immobilization of EGFR Nb (PHEMA-aEGFR surfaces). The high-density immobilized nanobody possessing maximized activity resulted in the high-efficiency capture of 81% rare A431 cells within just 30 min, showing a higher capture yield and shorter capture time compared with that achieved by the conventional antibody immobilized on the flat surface. Additionally, the PHEMA-aEGFR surfaces exhibited low capture limit (1 cell mL-1), cytocompatibility for captured cells, as well as negligible non-specific adhesion of PBMCs. With a one-step treatment using imidazole for competitive coordination, 86% of the captured cells were effectively released. This multifunctional and dynamic site-specifically immobilized nanobody strategy paves a new path in the development of materials and instruments for the high-efficiency capture and release of rare cells at a low cost.

Immunomagnetic separation of circulating tumor cells with microfluidic chips and their clinical applications

Circulating tumor cells (CTCs) are tumor cells detached from the original lesion and getting into the blood and lymphatic circulation systems. They potentially establish new tumors in remote areas, namely, metastasis. Isolation of CTCs and following biological molecular analysis facilitate investigating cancer and coming out treatment. Since CTCs carry important information on the primary tumor, they are vital in exploring the mechanism of cancer, metastasis, and diagnosis. However, CTCs are very difficult to separate due to their extreme heterogeneity and rarity in blood. Recently, advanced technologies, such as nanosurfaces, quantum dots, and Raman spectroscopy, have been integrated with microfluidic chips. These achievements enable the next generation isolation technologies and subsequent biological analysis of CTCs. In this review, we summarize CTCs' separation with microfluidic chips based on the principle of immunomagnetic isolation of CTCs. Fundamental insights, clinical applications, and potential future directions are discussed.

In Situ-Generated Multivalent Aptamer Network for Efficient Capture and Sensitive Electrochemical Detection of Circulating Tumor Cells in Whole Blood

Monitoring circulating tumor cells (CTCs) in human blood can offer useful information for convenient metastasis diagnosis, prognosis, and treatment of cancers. However, it remains a substantial challenge to detect CTCs because of their particular scarcity in complex peripheral blood. Herein, we describe an in situ-generated multivalent aptamer network-modified electrode interface for efficiently capturing and sensitively detecting CTCs in whole blood by electrochemistry. Such an interface was fabricated via rolling circle amplification extension of the electrode-immobilized primer/circular DNA complexes for the yield of long ssDNA strands with many repeated aptamer segments, which could achieve efficient capture of rare CTCs in a multivalent cooperative manner. The antibody and horseradish peroxidase-functionalized gold nanoparticles further specifically associated with the surface-bound CTCs and generated electrocatalytically amplified current outputs for highly sensitive detection of CTCs with an attractive detection limit of five cells. Also, the multivalent aptamer network interface could successfully distinguish the target cells from other control cells and achieve CTC detection in whole blood, demonstrating its promising potential for monitoring different rare CTCs in human blood.

A fluorescent immunosensor for determination and imaging of circulating tumor cells based on a bifunctional DNA nanomachine

A fluorescent platform was developed for the determination and visualization of circulating tumor cells by a toehold-mediated bifunctional DNA nanomachine. In the presence of target tumor cells, the DNA nanomachine was activated. Multiple DNA products were formed, including dendritic DNA products and double-strand DNA products. Dendritic DNA products bound to their target cells for the visualization, while double-strand DNA products were released for the determination of tumor cells. At fluorescence excitation and emission wavelengths of 530 and 550 nm, this method could detect as low as 43 cells/mL (S/N = 3) with a linear range of 100 to 10,000 cells/mL. In clinical hydrothorax samples, this platform exhibited high reliability with a recovery of 93 to 116%. At the fluorescence excitation and emission wavelengths of 490 and 515 nm, the specificity and biocompatibility of this method were further verified by tumor cells imaging. Furthermore, the robustness of the toehold-mediated bifunctional DNA nanomachine was demonstrated by the specific gene mutation detection in single-cell analysis. Graphical abstract Schematic illustration of the fluorescent immunosensor for determination and imaging of circulating tumor cells. The method is based on aptamer-based recognition and toehold-mediated bifunctional DNA nanomachine.

Applications of Two-Dimensional Nanomaterials in Breast Cancer Theranostics

Breast cancer is the leading cause of cancer-related mortality among women. Early stage diagnosis and treatment of this cancer are crucial to patients' survival. In addition, it is important to avoid severe side effects during the process of conventional treatments (surgery, chemotherapy, hormonal therapy, and targeted therapy) and increase the patients' quality of life. Over the past decade, nanomaterials of all kinds have shown excellent prospects in different aspects of oncology. Among them, two-dimensional (2D) nanomaterials are unique due to their physical and chemical properties. The functional variability of 2D nanomaterials stems from their large specific surface area as well as the diversity of composition, electronic configurations, interlayer forces, surface functionalities, and charges. In this review, the current status of 2D nanomaterials in breast cancer diagnosis and therapy is reviewed. In this respect, sensing of the tumor biomarkers, imaging, therapy, and theranostics are discussed. The ever-growing 2D nanomaterials are building blocks for the development of a myriad of nanotheranostics. Accordingly, there is the possibility to explore yet novel properties, biological effects, and oncological applications.

Capture and selective release of multiple types of circulating tumor cells using smart DNAzyme probes

The effective capture, release and reanalysis of circulating tumor cells (CTCs) are of great significance to acquire tumor information and promote the progress of tumor therapy. Particularly, the selective release of multiple types of CTCs is critical to further study; however, it is still a great challenge. To meet this challenge, we designed a smart DNAzyme probe-based platform. By combining multiple targeting aptamers and multiple metal ion responsive DNAzymes, efficient capture and selective release of multiple types CTCs were realized. Sgc8c aptamer integrated Cu2+-dependent DNAzyme and TD05 aptamer integrated Mg2+-dependent DNAzyme can capture CCRF-CEM cells and Ramos cells respectively on the substrate. With the addition of Cu2+ or Mg2+, CCRF-CEM cells or Ramos cells will be released from the substrate with specific selectivity. Furthermore, our platform has been successfully demonstrated in the whole blood sample. Therefore, our capture/release platform will benefit research on the molecular analysis of CTCs after release and has great potential for cancer diagnosis and individualized treatment.

Graphene based sensors

The two dimensional, honeycomb structured, single carbon layered graphene has extensively been used in the field of sensor detection due to its unique physicochemical properties. These properties such as excellent electrical conductivity, high electron mobility, tunable optical properties, room temperature quantum Hall effect, large surface to volume ratio, high mechanical strength, and ease of functionalization, make it an ideal nanomaterial for sensor development. This has enabled the fabrication of a large variety of highly sensitive sensors which include colorimetric, electrochemical, potentiometric, fluorescence, etc. based sensors. These sensors in conjugation with graphene or its derivatives such as graphene quantum dots, graphene oxide, reduced graphene oxide, etc. show highly desirable properties such as high sensitivity (detecting minute amounts of target analyte), specificity (no cross reactivity while detecting the target analyte), rapid results, low cost, extended storage shelf life and robustness (stability), and easy-to-use capabilities (user-friendly). This book chapter gives a detailed overview of all the advances made in the development and fabrication of novel graphene based sensors and their application in point of care (PoC) detection of various diseases as well as health monitoring devices. The different sensors, their methods of fabrication, their sensitivity and the analytes and biomolecules used have been discussed in detail and compared.

Circulating Tumor Cell Enrichment Technologies

Circulating tumor cells (CTCs) are responsible for the metastatic spread of cancer and therefore are extremely valuable not only for basic research on cancer metastasis but also as potential biomarkers in diagnosing and managing cancer in the clinic. While relatively non-invasive access to the blood tissue presents an opportunity, CTCs are mixed with approximately billion-times more-populated blood cells in circulation. Therefore, the accuracy of technologies for reliable enrichment of the rare CTC population from blood samples is critical to the success of downstream analyses. The focus of this chapter is to provide the reader an overview of significant advances made in the development of diverse CTC enrichment technologies by presenting the strengths of individual techniques in addition to specific challenges remaining to be addressed.

Emerging Nanotechnologies for Liquid Biopsy: The Detection of Circulating Tumor Cells and Extracellular Vesicles

Liquid biopsy enables noninvasive and dynamic analysis of molecular or cellular biomarkers, and therefore holds great potential for the diagnosis, prognosis, monitoring of disease progress and treatment efficacy, understanding of disease mechanisms, and identification of therapeutic targets for drug development. In this review, the recent progress in nanomaterials, nanostructures, nanodevices, and nanosensors for liquid biopsy is summarized, with a focus on the detection and molecular characterization of circulating tumor cells (CTCs) and extracellular vesicles (EVs). The developments and advances of nanomaterials and nanostructures in enhancing the sensitivity, specificity, and purity for the detection of CTCs and EVs are discussed. Sensing techniques for signal transduction and amplification as well as visualization strategies are also discussed. New technologies for the reversible release of the isolated CTCs and EVs and for single-CTC/EV analysis are summarized. Emerging microfluidic platforms for the integral on-chip isolation, detection, and molecular analysis are also included. The opportunities, challenges, and prospects of these innovative materials and technologies, especially with regard to their feasibility in clinical applications, are discussed. The applications of nanotechnology-based liquid biopsy will bring new insight into the clinical practice in monitoring and treatment of tumor and other significant diseases.

Optical and electrochemical-based nano-aptasensing approaches for the detection of circulating tumor cells (CTCs)

More recently, detection of circulating tumor cells (CTCs) has been considered as an appealing prognostic and diagnostic approach for cancer patients. CTCs as a type of tumor-derived cells are secreted by the tumor and released into the blood circulation. Since the migration of CTCs is an early event in cancer progression, patients who still have tumor-free lymph nodes have to be well examined for the CTCs presence in their blood circulation. Nowadays, there is a broad range of detection methods available to identify CTCs. As artificial RNA oligonucleotides or single-stranded DNA with receptor and catalytic characteristics, aptamers have been standing out, owing to their target-induced conformational modifications, elevated stability, and target specificity to be implemented in biosensing techniques. To date, several sensitivity-enhancement methods alongside smart nanomaterials have been used for the creation of new aptasensors to address the limit of detection (LOD), and improve the sensitivity of numerous analyte identification methods. The present review article supports a focused overview of the recent studies in the identification and quantitative determination of CTCs by aptamer-based biosensors and nanobiosensors.

Highly specific and sensitive point-of-care detection of rare circulating tumor cells in whole blood via a dual recognition strategy

Despite the fact that the identification and detection of circulating tumor cells (CTCs) plays a critical role in cancer monitoring and diagnosis, it remains a major challenge to isolate and detect these cells, due to their extreme scarcity in peripheral blood. In this work, by coupling a dual recognition strategy and the commercial personal glucose meter, we established a point-of-care approach for detecting rare CTCs in whole blood with high sensitivity and selectivity. The antibody-conjugated magnetic beads lead to the capture and isolation of the CTCs while the enzyme- and second antibody-modified microspheres yield the signal for detection. Because of the dual recognition format, the developed method is highly selective, and a low detection limit of 7 cells can be realized as well, owing to the great signal amplification through the enzyme-loaded microbead labels. More importantly, the detection of CTCs in whole blood can be achieved in a point-of-care fashion with the using of the glucose meter transducer, offering our method a convenient and attractive alternative to traditional biopsy for the diagnosis of various cancers.

Graphene- and Graphene Oxide-Based Nanocomposite Platforms for Electrochemical Biosensing Applications

Graphene and its derivatives such as graphene oxide (GO) and reduced GO (rGO) offer excellent electrical, mechanical and electrochemical properties. Further, due to the presence of high surface area, and a rich oxygen and defect framework, they are able to form nanocomposites with metal/semiconductor nanoparticles, metal oxides, quantum dots and polymers. Such nanocomposites are becoming increasingly useful as electrochemical biosensing platforms. In this review, we present a brief introduction on the aforementioned graphene derivatives, and discuss their synthetic strategies and structure-property relationships important for biosensing. We then highlight different nanocomposite platforms that have been developed for electrochemical biosensing, introducing enzymatic biosensors, followed by non-enzymatic biosensors and immunosensors. Additionally, we briefly discuss their role in the emerging field of biomedical cell capture. Finally, a brief outlook on these topics is presented.

Pea-like nanocabins enable autonomous cruise and step-by-step drug pushing for deep tumor inhibition

Pea-like nanocabins (HA@APT§DOX) were designed for deep tumor inhibition. The AS1411 aptamer (APT) constituted "core shelf" which guaranteed DOX "beans" could be embedded, while the outer HA acted as "pea shell" coating. During the circulation (primary orbit), HA@APT§DOX could autonomously cruise until leak through tumor vasculature. Upon tumor superficial site, the "pea shell" could be degraded by highly expressed hyaluronic acid enzymes (HAase) and peel-off, resulting in orbit changing of released APT§DOX to reach the deep tumor tissue. Furthermore, APT§DOX could be specifically uptaken into A549 tumor cells (secondary orbit). Finally, DOX was released under the acidic environment of lysosome, and delivered into nuclear (targeting orbit) to achieve drug pushing for deep tumor inhibition. More importantly, the in vivo imaging and anti-tumor effects evaluations showed that these nanocabins could effectively enhance drugs accumulation in tumor sites and inhibit tumor growth, with reduced systemic toxicity in 4T1 tumor-bearing mice.

Molecular Engineering of Functional Nucleic Acid Nanomaterials toward In Vivo Applications

Recent advances in nanotechnology and engineering have generated many nanomaterials with unique physical and chemical properties. Over the past decade, numerous nanomaterials are introduced into many research areas, such as sensors for environmental monitoring, food safety, point-of-care diagnostics, and as transducers for solar energy transfer. Meanwhile, functional nucleic acids (FNAs), including nucleic acid enzymes, aptamers, and aptazymes, have attracted major attention from the biomedical community due to their unique target recognition and catalytic properties. Benefiting from the recent progress of molecular engineering strategies, the physicochemical properties of nanomaterials are endowed by the target recognition and catalytic activity of FNAs in the presence of a target analyte, resulting in numerous smart nanoprobes for diverse applications including intracellular imaging, drug delivery, in vivo imaging, and tumor therapy. This progress report focuses on the recent advances in designing and engineering FNA-based nanomaterials, highlighting the functional outcomes toward in vivo applications. The challenges and opportunities for the future translation of FNA-based nanomaterials into clinical applications are also discussed.

Nanofiber-integrated miniaturized systems: an intelligent platform for cancer diagnosis

Cancer diagnostic tools enabling screening, diagnosis, and effective disease management are essential elements to increase the survival rate of diagnosed patients. Low abundance of cancer markers present in large amounts of interferences remains the major issue. Moreover, current diagnostic technologies are restricted to high-resourced settings only. Integrating nanofibers into miniaturized analytical systems holds a significant promise to address these challenges as demonstrated by recent publications. A large surface area, three-dimensional porous network, and diverse range of functional chemistries make nanofibers an excellent candidate as immobilization support and/or transduction elements, enabling high capture yield and ultrasensitive detection in miniaturized devices. Functional nanofibers have thus been used to isolate and detect various cancer-related biomarkers with a high degree of success in both on-chip and off-chip platforms. In fact, the chemical and functional adaptability of nanofibers has been exploited to address the technical challenges unique to each of the cancer markers in body fluids, where circulating tumor cells are prominently investigated among others (proteins, nucleic acids, and exosomes). So far, none of the work has exploited the nanofibers for cancer-derived exosomes, opening an avenue for further research effort. The trend and future prospects signal possibilities to strengthen the implementation of nanofiber-miniaturized system hybrid for a next generation of cancer diagnostic platforms both in clinical and point-of-care testing.

Potential use of aptamers for diagnosis and treatment of pancreatic cancer

Pancreatic cancer (PC) is highly malignant with a low 5-year survival rate. PC currently does not have good early diagnostic markers and responses poorly to chemotherapeutic drugs. The search for better biomarkers and developing more effective chemotherapy are important ways to improve the healthcare of PC patients. Aptamers are single-stranded nucleic acids with high binding affinity and specificity to target molecules. Many aptamers against different forms of cancer including PC have been selected for both diagnostic and therapeutic use. Aptamers can work as ligands to distinguish tumour cells from normal cells. Using cells as selection targets, the obtained aptamers have been used to discover new cancer biomarkers after identification of the binding target. Aptamers have been shown to have antagonists effect on cancer cell proliferation, apoptosis, and metastasis. In addition, aptamers have been used as carriers to deliver therapeutic agents to selectively kill PC cells. This review summarises the potential use of aptamers in the diagnosis and treatment of PC.

Current detection technologies for circulating tumor cells

Circulating tumor cells (CTCs) are cancer cells that circulate in the blood stream after being naturally shed from original or metastatic tumors, and can lead to a new fatal metastasis. CTCs have become a hotspot research field during the last decade. Detection of CTCs, as a liquid biopsy of tumors, can be used for early diagnosis of cancers, earlier evaluation of cancer recurrence and chemotherapeutic efficacy, and choice of individual sensitive anti-cancer drugs. Therefore, CTC detection is a crucial tool to fight against cancer. Herein, we classify the currently reported CTC detection technologies, introduce some representative samples for each technology, conclude the advantages and limitations, and give a future perspective including the challenges and opportunities of CTC detection.

Self-assembled, bivalent aptamers on graphene oxide as an efficient anticoagulant

Graphene oxide (GO) has unique structural properties, can effectively adsorb single-strand DNA through π-π stacking, hydrogen bonding and hydrophobic interactions, and is useful in many biotechnology applications. In this study, we developed a thrombin-binding-aptamers (15- and 29-mer) conjugated graphene oxide (TBA15/TBA29-GO) composite for the efficient inhibition of thrombin activity towards the formation of fibrin from fibrinogen. The TBA15/TBA29-GO composite was simply obtained by the self-assembly of TBA15/TBA29 hybrids on GO. The high density and appropriate orientation of TBA15/TBA29 on the GO surface enabled TBA15/TBA29-GO to acquire an ultrastrong binding affinity for thrombin (dissociation constant = 2.9 × 10-12 M). Compared to bivalent TBA15h20A20/TBA29h20A20 hybrids, the TBA15/TBA29-GO composite exhibited a superior anticoagulant potency (ca. 10-fold) against thrombin-mediated coagulation as a result of steric blocking effects and a higher binding affinity for thrombin. In addition, the prolonged thrombin clotting time, prothrombin time (PT), and activated partial thromboplastin time (aPTT) of TBA15/TBA29-GO were at least 2 times longer than those of commercially available drugs (heparin, argatroban, hirudin, and warfarin). The in vitro cytotoxicity and hemolysis analyses revealed the high biocompatibility of TBA15/TBA29-GO. The rat-tail bleeding assay of the hemostasis time and ex vivo PT and aPTT further revealed that TBA15/TBA29-GO is superior (>2-fold) to heparin, which is commonly used in the treatment and prevention of thrombotic diseases. Our multivalent, oligonucleotide-modified GO nanocomposites are easy to prepare, cost-effective, and highly biocompatible and they show great potential as effective anticoagulants for the treatment of thrombotic disorders.

Microfluidic technologies in cell isolation and analysis for biomedical applications

Efficient platforms for cell isolation and analysis play an important role in applied and fundamental biomedical studies. As cells commonly have a size of around 10 microns, conventional handling approaches at a large scale are still challenged in precise control and efficient recognition of cells for further performance of isolation and analysis. Microfluidic technologies have become more prominent in highly efficient cell isolation for circulating tumor cells (CTCs) detection, single-cell analysis and stem cell separation, since microfabricated devices allow for the spatial and temporal control of complex biochemistries and geometries by matching cell morphology and hydrodynamic traps in a fluidic network, as well as enabling specific recognition with functional biomolecules in the microchannels. In addition, the fabrication of nano-interfaces in the microchannels has been increasingly emerging as a very powerful strategy for enhancing the capability of cell capture by improving cell-interface interactions. In this review, we focus on highlighting recent advances in microfluidic technologies for cell isolation and analysis. We also describe the general biomedical applications of microfluidic cell isolation and analysis, and finally make a prospective for future studies.

Nucleic acid aptamers in diagnosis of colorectal cancer

Nucleic acid aptamers are promising recognition ligands for diagnostic applications. They are short DNA or RNA molecules isolated from large random libraries through the Systematic Evolution of Ligands by EXponential enrichment (SELEX) procedure. These molecules, with a particular three-dimensional shape, bind to a wide range of targets from small molecules to whole cells with high affinity and specificity. The unique properties of nucleic acid aptamers including high binding affinity and specificity, thermostability, ease of chemical production, ease of chemical modification, target adaptability, simple storage, resistance to denaturation, low immunogenicity, and low cost make them potential diagnostic tools for clinical use. Colorectal cancer is one of the most common types of cancer in humans and the third leading cause of cancer deaths in the world. Due to low response rate to current therapies in advanced stages of the disease, early detection of CRC can be useful in disease management. This review highlights recent advances in the development of nucleic acid aptamer-based methods for diagnosis, prognosis, and theranosis of colorectal cancer.

Aptamer chemistry

Aptamers are single-stranded DNA or RNA molecules capable of tightly binding to specific targets. These functional nucleic acids are obtained by an in vitro Darwinian evolution method coined SELEX (Systematic Evolution of Ligands by EXponential enrichment). Compared to their proteinaceous counterparts, aptamers offer a number of advantages including a low immunogenicity, a relative ease of large-scale synthesis at affordable costs with little or no batch-to-batch variation, physical stability, and facile chemical modification. These alluring properties have propelled aptamers into the forefront of numerous practical applications such as the development of therapeutic and diagnostic agents as well as the construction of biosensing platforms. However, commercial success of aptamers still proceeds at a weak pace. The main factors responsible for this delay are the susceptibility of aptamers to degradation by nucleases, their rapid renal filtration, suboptimal thermal stability, and the lack of functional group diversity. Here, we describe the different chemical methods available to mitigate these shortcomings. Particularly, we describe the chemical post-SELEX processing of aptamers to include functional groups as well as the inclusion of modified nucleoside triphosphates into the SELEX protocol. These methods will be illustrated with successful examples of chemically modified aptamers used as drug delivery systems, in therapeutic applications, and as biosensing devices.

Dual-Selective and Dual-Enhanced SERS Nanoprobes Strategy for Circulating Hepatocellular Carcinoma Cells Detection

The detection of hepatocellular carcinoma (HCC) circulating tumor cells (CTCs) from a blood sample can be a very powerful noninvasive approach for the early detection and therapy of liver cancer. However, the extreme rarity of tumor cells in blood containing billions of other cells makes the capture and identification of CTCs with sufficient sensitivity and specificity a real challenge. Here, a magnetically assisted surface-enhanced Raman scattering (SERS) biosensor for HCC CTC detection is reported for the first time. The biosensor consists of two basic elements: anti-ASGPR antibody-Fe₃ O₄ @Ag magnetic nanoparticles and anti-GPC3 antibody-Au@Ag@DTNB nanorods. According to the dual-selectivity of the anti-ASGPR and anti-GPC3 antibodies and the dual-enhancement SERS signal of the MNPs silver shell and the Au@Ag NRs SERS tags, a limit of detection of 1 cell mL^-1 for HCC CTC in human peripheral blood samples with a linear relationship from 1 to 100 cells mL^-1 can be obtained. The system shows good performance in real serum, which suggests it may be a promising tool for HCC clinical diagnosis.

Improved Detection of HER2 by a Quasi-Targeted Proteomics Approach Using Aptamer–Peptide Probe and Liquid Chromatography–Tandem Mass Spectrometry

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is a particularly aggressive type of the disease. To date, much evidence has indicated that accurate HER2 status detection is crucial for prognosis and treatment strategy selection. Thus, bioanalytical techniques for early and accurate detection of HER2 have the potential to improve patient care. Currently, the widely used immunohistochemical staining normally has problems with reproducibility and lack of standardization, resulting in poor concordance between laboratories. Aptamers are a good alternative, but the extent of their use in quantitative analysis of HER2 is limited because of the lack of effective detection methods.

METHODS

We developed a quasi-targeted proteomics assay and converted the HER2 signal into the mass response of reporter peptide by a combination of aptamer–peptide probe and LC-MS/MS.

RESULTS

The selected aptamer–peptide probe consisted of aptamer HB5 and the substrate peptide GDKAVLGVDPFR that contained the reporter peptide AVLGVDPFR. After characterization of this newly synthesized probe (e.g., conjugation efficiency, stability, binding affinity, specificity, and digestion efficiency), probe binding and trypsin shaving conditions were optimized. The resulting limit of quantification for HER2 was 25 pmol/L. Then, the quasi-targeted proteomics assay was applied to determine the HER2 concentrations in the HER2-positive breast cancer cells BT474 and SK-BR-3, the HER2-negative breast cancer cells MDA-MB-231 and MCF-7, and 36 pairs of human breast primary tumors and adjacent normal tissue samples. The results were highly concordant with those obtained by immunohistochemistry with reflex testing by fluorescent in situ hybridization.

CONCLUSIONS

Quasi-targeted proteomics can be a quantitative alternative for HER2 detection.

Multifunctional hybrid graphene oxide for circulating tumor cell isolation and analysis

Even in 21st century, >90% cancer-associated deaths are caused by metastatic disease. Circulating tumor cells (CTCs), which circulate in the blood stream after release from primary tumors, extravasate and form fatal metastases in different organs. Several clinical trials indicate that CTCs can be used as a liquid biopsy of tumors for early diagnosis of cancers. Since CTCs are extremely rare and exhibit heterogeneous biology due to epithelial-mesenchymal transition (EMT), oncologists continue to face enormous challenges in using CTCs as a true "liquid biopsy" for cancer patients. Recent advancements in nanoscience allow us to design nano-architectures with the capability of targeted CTCs isolation and identification. In the current review, we discuss contribution from different groups on the development of graphene oxide based nanoarchitecture for effective isolation and accurate identification of CTCs from whole blood. In the last few years, using zero-dimensional (0D), two dimensional (2D) and three dimensional (3D) multifunctional hybrid graphene oxide (GO), different types of nanoarchitectures have been designed. These nanoarchitectures represent a highly powerful platform for CTC diagnosis. We discuss the major design criteria that have been used to develop hybrid GO nanoarchitectures for selective capture and accurate identification of heterogeneous CTCs from whole blood. At the end, we conclude with the promises, major challenges, and prospect to clinically translate the identification of CTCs using GO based nanotechnology.

Clinical utility of non-EpCAM based circulating tumor cell assays

Methods enabling the isolation, detection, and characterization of circulating tumor cells (CTCs) in blood have clear potential to facilitate precision medicine approaches in patients with cancer, not only for prognostic purposes but also for prediction of the benefits of specific therapies in oncology. However, current CTC assays, which capture CTCs based on expression of epithelial cell adhesion molecule (EpCAM), fail to capture cells from de-differentiated tumors and carcinomas undergoing loss of the epithelial phenotype during the invasion/metastatic process. To address this limitation, many groups are developing non-EpCAM based CTC assays that incorporate nanotechnology to improve test sensitivity for rare but important cells that may otherwise go undetected, and therefore may improve upon clinical utility. In this review, we outline emerging non-EpCAM based CTC assays utilizing nanotechnology approaches for CTC capture or characterization, including dendrimers, magnetic nanoparticles, gold nanoparticles, negative selection chip or software-based on-slide methods, and nano-scale substrates. In addition, we address challenges that remain for the clinical translation of these platforms.

Apoptotic and Nonapoptotic Activities of Pterostilbene against Cancer

Cancer is a major cause of death. The outcomes of current therapeutic strategies against cancer often ironically lead to even increased mortality due to the subsequent drug resistance and to metastatic recurrence. Alternative medicines are thus urgently needed. Cumulative evidence has pointed out that pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene, PS) has excellent pharmacological benefits for the prevention and treatment for various types of cancer in their different stages of progression by evoking apoptotic or nonapoptotic anti-cancer activities. In this review article, we first update current knowledge regarding tumor progression toward accomplishment of metastasis. Subsequently, we review current literature regarding the anti-cancer activities of PS. Finally, we provide future perspectives to clinically utilize PS as novel cancer therapeutic remedies. We, therefore, conclude and propose that PS is one ideal alternative medicine to be administered in the diet as a nutritional supplement.