CdTe amplification nanoplatforms capped with thioglycolic acid for electrochemical aptasensing of ultra-traces of ATP

Radiolabeled nanomaterial for cancer diagnostics and therapeutics: principles and concepts

In the last three decades, radiopharmaceuticals have proven their effectiveness for cancer diagnosis and therapy. In parallel, the advances in nanotechnology have fueled a plethora of applications in biology and medicine. A convergence of these disciplines has emerged more recently with the advent of nanotechnology-aided radiopharmaceuticals. Capitalizing on the unique physical and functional properties of nanoparticles, radiolabeled nanomaterials or nano-radiopharmaceuticals have the potential to enhance imaging and therapy of human diseases. This article provides an overview of various radionuclides used in diagnostic, therapeutic, and theranostic applications, radionuclide production through different techniques, conventional radionuclide delivery systems, and advancements in the delivery systems for nanomaterials. The review also provides insights into fundamental concepts necessary to improve currently available radionuclide agents and formulate new nano-radiopharmaceuticals.

Recent Advances in Engineered Noble Metal Nanomaterials as a Surface-Enhanced Raman Scattering Active Platform for Cancer Diagnostics

Recently, noble metal nanomaterials have been extensively studied in the fields of biosensing, environmental catalysis, and cancer diagnosis and treatment, due to their excellent electrical conductivity, high surface area, and individual physical and optical properties. Early research on the surface-enhanced Raman scattering (SERS) effect was focused on the cognition of the SERS phenomenon and enhancing its sensitivity for single-molecule detection. With the development of nanomaterials and nanotechnology, the advances and applications based on SERS substrates have been accelerated. Among them, noble metal nanomaterials are mainly used as SERS-active substrates to enhance SERS signals owing to their compelling surface plasmon resonance (SPR) properties. This review provides recent advances, perspectives, and challenges in SERS assays based on engineered noble metal nanomaterials for early cancer diagnosis.

Design, Bioanalytical, and Biomedical Applications of Aptamer-Based Hydrogels

Aptamers are special types of single-stranded DNA generated by a process called systematic evolution of ligands by exponential enrichment (SELEX). Due to significant advances in the chemical synthesis and biotechnological production, aptamers have gained considerable attention as versatile building blocks for the next generation of soft materials. Hydrogels are high water-retainable materials with a three-dimensional (3D) polymeric network. Aptamers, as a vital element, have greatly expanded the applications of hydrogels. Due to their biocompatibility, selective binding, and molecular recognition, aptamer-based hydrogels can be utilized for bioanalytical and biomedical applications. In this review, we focus on the latest strategies of aptamer-based hydrogels in bioanalytical and biomedical applications. We begin this review with an overview of the underlying design principles for the construction of aptamer-based hydrogels. Next, we will discuss some bioanalytical and biomedical applications of aptamer-based hydrogel including biosensing, target capture and release, logic devices, gene and cancer therapy. Finally, the recent progress of aptamer-based hydrogels is discussed, along with challenges and future perspectives.

A review on nanostructure-based mercury (II) detection and monitoring focusing on aptamer and oligonucleotide biosensors

Heavy metal ion pollution is a severe problem in environmental protection and especially in human health due to their bioaccumulation in organisms. Mercury (II) (Hg²⁺), even at low concentrations, can lead to DNA damage and give permanent harm to the central nervous system by easily passing through biological membranes. Therefore, sensitive detection and monitoring of Hg²⁺ is of particular interest with significant specificity. In this review, aptamer-based strategies in combination with nanostructures as well as several other strategies to solve addressed problems in sensor development for Hg²⁺ are discussed in detail. In particular, the analytical performance of different aptamer and oligonucleotide-based strategies using different signal improvement approaches based on nanoparticles were compared within each strategy and in between. Although quite a number of the suggested methodologies analyzed in this review fulfills the standard requirements, further development is still needed on real sample analysis and analytical performance parameters.

Label-Free and Regenerable Aptasensor for Real-Time Detection of Cadmium(II) by Dual Polarization Interferometry

Recently, numerous aptamer-based biosensors have been developed to detect heavy metal ions. Most of aptamer-based biosensors only can be used to get some quantitative information. The mechanism of the interaction between aptamer and metal ions, however, is rarely studied. In this work, a label-free and regenerable aptamer-based biosensor was constructed using dual polarization interferometry (DPI). This aptasensor was used to investigate the real-time interaction process between cadmium(II) and its aptamer. According to the information on mass, thickness, and density obtained by DPI, a Cd²⁺ concentration-dependent interaction mechanism and conformation of aptamer was proposed. At low Cd²⁺ concentration, Cd²⁺ mainly interacted with phosphate groups on aptamer, resulting in the stretched ssDNA and a few vertical hairpin structures. When adding the high concentration of Cd²⁺, Cd²⁺ primarily bound with bases of DNA by coordination interaction and the conformation of aptamer transferred to a tight and short hairpin structure. In addition, the association rate constant (k_a), dissociation rate constant (k_d) and disassociation constant (K_D) between Cd²⁺ and its aptamer were calculated to be 96 M^-1 S^-1, 2.11 × 10^-5 S^-1, and 220 nM, respectively. The proposed aptasensor showed high sensitivity for Cd²⁺ detection with the detection limit of 0.61 μg/L, which was far below the 5.0 μg/L ranked by the U.S. Environmental Protection Agency. The biosensor also exhibited excellent regenerability and could be used for three cycles without obvious change in response signal. Therefore, the developed method could not only provide quantitative information, but also offered the information on conformation and kinetics for molecular interaction. This method can facilely extend to study the interaction of DNA with other ions, small molecules, or biomacromolecules.

Dual-modal label-free genosensor based on hemoglobin@gold nanocluster stabilized graphene nanosheets for the electrochemical detection of BCR/ABL fusion gene

For the first time, we have successfully synthesized stable graphene nanosheets from graphite powder through sonication in the hemoglobin-capped gold nanoclusters (Hb@AuNCs) solution for biosensing application. This approach, as a simple method for the exfoliation and fragmentation of graphite in a nanocluster solution, enabled us to produce stable aqueous graphene dispersions at low cost and without the need for hazardous chemicals or tedious experimental procedures. In this method, Hb@AuNCs were used not only as stabilizing agent of graphene through non-covalent bonding, but also as dispersing agent of few-layer graphene nanosheets. The Hb@AuNCs stabilized graphene (Hb@AuNCs-G) was characterized by high resolution transmission electron microscopy (HRTEM), zeta-sizer and Raman spectroscopy. Then, the graphene nanosheets were applied as a novel versatile electrochemical platform for ultrasensitive biosensing of short DNA species of chronic myelogenous leukemia (CML) based on the "signal off" and "signal on" strategies. For this purpose, a single strand DNA (ssDNA) was immobilized on the Hb@AuNCs-G/AuNPs modified electrode surface and acted as the biorecognition element. Methylene blue (MB), as the signaling probe, was then intercalated into the ssDNA. The intercalated MB was liberated upon interaction with the synthetic complementary DNA (cDNA, target), thereby resulting in the apparent reduction of MB redox signal. This designed "signal off" sensing system enabled the voltammetric determination of the target cDNA over a dynamic linear range (DLR) of 0.1 fM to 10 pM with a limit of detection (LOD) of 0.037 fM. In the "signal on" strategy, the response to the cDNA was detected by monitoring the change in the electron transfer resistance (R_ct) using the ferro/ferricyanide system as a redox probe. The charge transfer resistance of the probe was found to increase linearly with increasing concentration of target cDNA in the range of 0.1 fM-10 pM with a limit of detection of 0.030 fM. Finally, the selectivity and feasibility of genosensor was evaluated by the analysis of derived nucleotides from mismatched sequences and the clinical samples of patients with leukemia as real samples, respectively.

HIV biosensors for early diagnosis of infection: The intertwine of nanotechnology with sensing strategies

Human immunodeficiency virus (HIV) is a lentivirus that leads to acquired immunodeficiency syndrome (AIDS). With increasing awareness of AIDS emerging as a global public health threat, different HIV testing kits have been developed to detect antibodies (Ab) directed toward different parts of HIV. A great limitation of these tests is that they can not detect HIV antibodies during early virus infection. Therefore, to overcome this challenge, a wide range of biosensors have been developed for early diagnosis of HIV infection. A significant amount of these studies have been focused on the application of nanomaterials for improving the sensitivity and accuracy of the sensing methods. Following an introduction into this field, a first section of this review covers the synthesis and applicability of such nanomaterials as metal nanoparticles (NPs), quantum dots (QDs), carbon-based nanomaterials and metal nanoclusters (NCs). A second larger section covers the latest developments concerning nanomaterial-based biosensors for HIV diagnosis, with paying a special attention to the determination of CD4⁺ cells as a hall mark of HIV infection, HIV gene, HIV p24 core protein, HIV p17 peptide, HIV-1 virus-like particles (VLPs) and HIV related enzymes, particularly those that are passed on from the virus to the CD⁴⁺ T lymphocytes and are necessary for viral reproduction within the host cell. These studies are described in detail along with their diverse principles/mechanisms (e.g. electrochemistry, fluorescence, electromagnetic-piezoelectric, surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and colorimetry). Despite the significant progress in HIV biosensing in the last years, there is a great need for the development of point-of-care (POC) technologies which are affordable, robust, easy to use, portable, and possessing sufficient quantitative accuracy to enable clinical decision making. In the final section, the focus is on the portable sensing devices as a new standard of POC and personalized diagnostics.

Functionalized magnetic composites based on the aptamer serve as novel bio-adsorbent for the separation and preconcentration of trace lead

A magnetic functionalized bio-sorbent based on aptamer was designed for the selective separation of ultra-trace Pb²⁺, shortly termed as Fe₃O₄@Au@DNA. Pb(II) specific aptamer attached to the magnetic solid substrate served as affinity probe to capture and separate trace lead. Oligonucleotides with a polyA block were employed for the immobilization on the surface of AuNPs, with adenine sequences (polyA) as the part of effective anchoring block. The prepared Fe₃O₄@Au@DNA composites were characterized by FT-IR, SEM and XPS. The binding of lead on Fe₃O₄@Au@DNA composites surface was pH-dependent, the adsorption follows Langmuir model, and the adsorption dynamic fits the pseudo-second-order kinetics model. Procedure for lead separation and preconcentration was explored and combined with detection of graphite furnace atomic absorption spectrometry (GFAAS). Under the optimum condition, an enrichment factor of 17.73 was obtained with a sample volume of 1.0 mL. The limit of detection (LOD) was 57 ng L^-1 along with a relative standard deviation (RSD) of 2.06 (n = 9). The procedure was further validated by a certified reference material GBW08608 and several environmental and blood samples.

A review on nanomaterial-based electrochemical, optical, photoacoustic and magnetoelastic methods for determination of uranyl cation

This review (with 177 refs) gives an overview on nanomaterial-based methods for the determination of uranyl ion (UO₂²⁺) by different types of transducers. Following an introduction into the field, a first large section covers the fundamentals of selective recognition of uranyl ion by receptors such as antibodies, aptamers, DNAzymes, peptides, microorganisms, organic ionophores (such as salophens, catechols, phenanthrolines, annulenes, benzo-substituted macrocyclic diamides, organophosphorus receptors, calixarenes, crown ethers, cryptands and β-diketones), by ion imprinted polymers, and by functionalized nanomaterials. A second large section covers the various kinds of nanomaterials (NMs) used, specifically on NMs for electrochemical signal amplification, on NMs acting as signal tags or carriers for signal tags, on fluorescent NMs, on NMs for colorimetric assays, on light scattering NMs, on NMs for surface enhanced Raman scattering (SERS)-based assays and wireless magnetoelastic detection systems. We then discuss detection strategies, with subsections on electrochemical methods (including ion-selective and potentiometric systems, voltammetric systems and impedimetric systems). Further sections treat colorimetric, fluorometric, resonance light scattering-based, SERS-based and photoacoustic methods, and wireless magnetoelastic detection. The current state of the art is summarized, and current challenges are discussed at the end. Graphical abstract An overview is given on nanomaterial-based methods for the detection of uranyl ion by different types of transducers (such as electrochemical, optical, photoacoustic, magnetoelastic, etc) along with a critical discussion of their limitations, benefits and application to real samples.

A glassy carbon electrode modified with graphene oxide, poly(3,4-ethylenedioxythiophene), an antifouling peptide and an aptamer for ultrasensitive detection of adenosine triphosphate

An antifouling aptasensor is described for voltammetric determination of adenosine triphosphate (ATP). A glassy carbon electrode (GCE) was modified with a graphene oxide and poly(3,4-ethylenedioxythiophene) (GO-PEDOT) composite film by electrodeposition. Next, the zwitterionic peptide (EKEKEKE) was attached. It forms an antifouling layer on the modified GCE and serves as the support for subsequent aptamer immobilization. The resulting aptasensor typically is operated at a potential of 0.18 V (vs. SCE) using hexacyanoferrate as the electrochemical probe. It has a linear response in the 0.1 pM to 1.0 μM ATP concentration range, a 0.03 pM detection limit and a sensitivity of 2674.7 μA·μM^-1·cm^-2. It has outstanding selectivity, satisfactory reproducibility and desired stability. It was used to quantify ATP in ATP-spiked 10% serum solutions. Graphical abstract Schematic presentation of the construction of the aptamer based electrode for voltammetric determination of ATP.

Employing AgNPs doped amidoxime-modified polyacrylonitrile (PAN-oxime) nanofibers for target induced strand displacement-based electrochemical aptasensing of CA125 in ovarian cancer patients

In this study, a high-performance biosensing nanoplatform based on amidoxime-modified polyacrylonitrile nanofibers decorated with Ag nanoparticles (AgNPs-PAN-oxime NFs) is described. The AgNPs-PAN-oxime NFs were prepared by the combination of electrospinning technique and chemical modification of nitrile group in the PAN. The proposed signal amplifiying nanoplatform was applied in the fabrication of an electrochemical aptasensor for the sensitive detection of CA 125 based on aptamer-cDNA duplex and target induced strand displacement recognition mechanism. The aptasensing interface offers high sensitivity and selectivity for detection of tumor marker due to inherent advantages such as high specific surface area of NFs, good conductivity by doping AgNPs into the polymer NFs and especially the ideal selectivity of anti CA 125 aptamer to its target. The electrochemical aptasensor revealed a wide dynamic linear range (DLR) from 0.01 to 350 U mL^-1 with a correlation coefficient of 0.991 and limit of detection (LOD) of 0.0042 U mL^-1. Additionally, the designed aptasensor showed acceptable selectivity, reproducibility, repeatability and stability. The satisfactory results for determination of CA 125 in serum samples compared to ELISA method (p-value > 0.05) indicated the potential application of aptasensor in clinical monitoring of tumor biomarker for early diagnosis and management of ovarian cancer.

Clinical aspects of radiolabeled aptamers in diagnostic nuclear medicine: A new class of targeted radiopharmaceuticals

Targeted radiopharmaceuticals offer the possibility of improved imaging with reduced side effects. Up to now, a variety of biological receptors such as aptamers have been successfully radiolabeled and applied to diagnostic imaging of cancers. The concept of using radio-labeled aptamers for binding to their targets has stimulated an immense body of research in diagnostic nuclear medicine. These biological recognition elements are single-stranded oligonucleotides that interact with their target molecules with high affinity and specificity in unique three-dimensional structures. Because of their high affinity and specificity, the receptor-binding aptamers labeled with gamma emitters such as ^99mTc, ⁶⁴Cu, ¹¹¹In, ¹⁸F and ⁶⁷Ga can facilitate the visualization of receptor-expressing tissues noninvasively. Compared to the antibody-based radiopharmaceuticals, the radiolabeled aptamers provide a number of advantages for clinical diagnostics including high stability, low cost, and ease of production and modification, low immunogenicity and, especially, superior tissue penetration because of their smaller size. In this review, we present recent progresses and challenges in aptamer-based diagnostic radiopharmaceuticals and highlight some representative applications of aptamers in nuclear medicine.

An overview of nanoscale radionuclides and radiolabeled nanomaterials commonly used for nuclear molecular imaging and therapeutic functions

Recent advances in the field of nanotechnology applications in nuclear medicine offer the promise of better diagnostic and therapeutic options. In recent years, increasing efforts have been focused on developing nanoconstructs that can be used as core platforms for attaching medical radionuclides with different strategies for the purposes of molecular imaging and targeted drug delivery. This review article presents an introduction to some commonly used nanomaterials with zero-dimensional, one-dimensional, two-dimensional, and three-dimensional structures, describes the various methods applied to radiolabeling of nanomaterials, and provides illustrative examples of application of the nanoscale radionuclides or radiolabeled nanocarriers in nuclear nanomedicine. Especially, the passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy was reviewed and summarized. The accurate and early diagnosis of cancer can lead to increased survival rates for different types of this disease. Although, the conventional single-modality diagnostic methods such as positron emission tomography/single photon emission computed tomography or MRI used for such purposes are powerful means; most of these are limited by sensitivity or resolution. By integrating complementary signal reporters into a single nanoparticulate contrast agent, multimodal molecular imaging can be performed as scalable images with high sensitivity, resolution, and specificity. The advent of radiolabeled nanocarriers or radioisotope-loaded nanomaterials with magnetic, plasmonic, or fluorescent properties has stimulated growing interest in the developing multimodality imaging probes. These new developments in nuclear nanomedicine are expected to introduce a paradigm shift in multimodal molecular imaging and thereby opening up an era of new diagnostic medical imaging agents. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 251-285, 2019.

Recent advances in designing nanomaterial based biointerfaces for electrochemical biosensing cardiovascular biomarkers

Early diagnosis of cardiovascular disease (CVD) is critically important for successful treatment and recovery of patients. At present, detection of CVD at early stages of its progression becomes a major issue for world health. The nanoscale electrochemical biosensors exhibit diverse outstanding properties, rendering them extremely suitable for the determination of CVD biomarkers at very low concentrations in biological fluids. The unique advantages offered by electrochemical biosensors in terms of sensitivity and stability imparted by nanostructuring the electrode surface together with high affinity and selectivity of bioreceptors have led to the development of new electrochemical biosensing strategies that have introduced as interesting alternatives to conventional methodologies for clinical diagnostics of CVD. This review provides an updated overview of selected examples during the period 2005-2018 involving electrochemical biosensing approaches and signal amplification strategies based on nanomaterials, which have been applied for determination of CVD biomarkers. The studied CVD biomarkers include AXL receptor tyrosine kinase, apolipoproteins, cholesterol, C-reactive protein (CRP), D-dimer, fibrinogen (Fib), glucose, insulin, interleukins, lipoproteins, myoglobin, N-terminal pro-B-type natriuretic peptide (BNP), tumor necrosis factor alpha (TNF-α) and troponins (Tns) on electrochemical transduction format. Identification of new specific CVD biomarkers, multiplex bioassay for the simultaneous determination of biomarkers, emergence of microfluidic biosensors, real-time analysis of biomarkers and point of care validation with high sensitivity and selectivity are the major challenges for future research.

Advances in the design of nanomaterial-based electrochemical affinity and enzymatic biosensors for metabolic biomarkers: A review

This review (with 340 refs) focuses on methods for specific and sensitive detection of metabolites for diagnostic purposes, with particular emphasis on electrochemical nanomaterial-based sensors. It also covers novel candidate metabolites as potential biomarkers for diseases such as neurodegenerative diseases, autism spectrum disorder and hepatitis. Following an introduction into the field of metabolic biomarkers, a first major section classifies electrochemical biosensors according to the bioreceptor type (enzymatic, immuno, apta and peptide based sensors). A next section covers applications of nanomaterials in electrochemical biosensing (with subsections on the classification of nanomaterials, electrochemical approaches for signal generation and amplification using nanomaterials, and on nanomaterials as tags). A next large sections treats candidate metabolic biomarkers for diagnosis of diseases (in the context with metabolomics), with subsections on biomarkers for neurodegenerative diseases, autism spectrum disorder and hepatitis. The Conclusion addresses current challenges and future perspectives. Graphical abstract This review focuses on the recent developments in electrochemical biosensors based on the use of nanomaterials for the detection of metabolic biomarkers. It covers the critical metabolites for some diseases such as neurodegenerative diseases, autism spectrum disorder and hepatitis.

Magnetically controlled fluorescence aptasensor for simultaneous determination of ochratoxin A and aflatoxin B1

Development of an efficient method for the simultaneous detection of two highly concerning mycotoxins, ochratoxin A (OTA) and aflatoxin B1 (AFB1), is of great significance on food safety monitoring. Herein, a magnetically controlled fluorescence aptasensor for simultaneous determination of OTA and AFB1 has been successfully developed. The working principle of the aptasensor is based on the specific aptamer-mycotoxin recognition and further leads to the partial release of two distinguishable fluorescence labels from the magnetic carriers. Through the magnetic separation, the reporter probes in the supernatant solution can be collected and converted into a sensitive fluorescence signal with dual emission peaks. This aptasensor provided a wide detection range of 2 pg mL^-1 - 5 ng mL^-1 for OTA and 5 pg mL^-1 - 10 ng mL^-1 for AFB1. The new easy-to-wash and simple-to-use approach offers a simultaneous and high selective detection with high sensitivity (limits of detection of 0.67 and 1.70 pg mL^-1 for OTA and AFB1, respectively). Remarkable accuracy (relative standard deviation < 5.6%) during the mycotoxins determination as well as excellent quantitative recoveries (95-108%) during the analysis of the spiked corn samples were also achieved. This simple aptasensing scheme provides a new avenue for high throughput screen of dual mycotoxins due to its simple manipulation, short assay times, high selectivity and sensitivity.

Signalling probe displacement electrochemical aptasensor for malignant cell surface nucleolin as a breast cancer biomarker based on gold nanoparticle decorated hydroxyapatite nanorods and silver nanoparticle labels

Nucleolin is a multifunctional protein that is markedly overexpressed on the surface of most cancer cells. By taking advantage of the high affinity and specificity of the AS1411 aptamer for nucleolin, a signalling probe displacement electrochemical aptasensor was developed. The thiolated AS1411 aptamer was conjugated to hydroxyapatite nanorods (HApNRs) decorated with gold nanoparticles (AuNPs). To further increase the electrical conductivity of the interface, the ionic liquid 1-ethyl-3-methylimidazolium alanine with its high ion conductivity was placed on the electrode surface. Then, the aptamer was immobilized on the modified electrode and conjugated to signalling c-DNA tagged with AgNPs (c-DNA@AgNPs). In the presence of the MCF7 target cells, the signalling probe is displaced and released from the electrode surface. This leads to a decrease in the current that is proportional to the concentration of cancer cells in the range from 10 to 106 cells mL-1, with a detection limit as low as 8 ± 2 cells mL-1 (n = 3) (based as 3σ/m, where σ is the standard deviation of the blank and m is the slope of the calibration plot). This method presents a promising tool for highly sensitive and selective detection of surface nucleolin on MCF7 cancer cells. Graphical abstract HApNR-AuNP-AS1411 aptamer nanocomposite as an electrochemical sensing interface was immobilized on the gold electrode surface and conjugated to signaling c-DNA tagged with AgNPs for determination of surface nucleolin on MCF7 cancer cells.

Label-free Electrochemical Detection of ATP Based on Amino-functionalized Metal-organic Framework

A sensitive, selective and recyclable electrochemical sensor is designed for ATP detection based on amino-functionalized metal-organic framework. The functional MOF as the sensor is constructed by one-step synthesis Ce-MOF and sequentially modified on the Au electrode and conjugated with the aptamer of ATP. The presence of target ATP leads to the conformational change of aptamer strands and strong electrochemical impedance. The electrochemical sensor can detect ATP down to 5.6 nM with the linear range of 10 nm to 1000 μM. The present study is the first report on the use of MOF as an electrochemical sensor for ATP at nM level. This strategy has been successfully applied in detection of ATP in serum of cancer patients, which reveals its potential application in clinical diagnosis.

A review: Aptamer-based analytical strategies using the nanomaterials for environmental and human monitoring of toxic heavy metals

Recent developments in biotechnology offer the new methods for the sensitive detection of heavy metals based on the affinity and specificity of aptamers, as nucleic acid ligands selected from random sequence pools in vitro. Heavy metals have received considerable importance as the most toxic metallic pollutants which may cause serious environmental damages. They are classified as trace elements because of their presence in trace concentrations in various environmental matrices. Thus, the precise and sensitive methods to detect heavy metals are important to ensure human and environment safety. Aptamers as the biological probes, show high binding affinity which can often be directly translated into high detection sensitivity. On the other hand, high selectivity and stability make them possible to detect a wide range of targets, especially metallic ions. This review provides current progress of aptamers for environmental and biological monitoring of heavy metals using the nanomaterials mainly in two groups: (i) aptamer based biosensors (aptasensors) and (ii) aptamer based biosorbents (aptasorbents). The introduction of nanomaterials can efficiently increase the immobilization quantity of aptamers. Furthermore, they play an important role in the orientation and assembly density controlling of aptamers for the optimized recognition ability.