Nanoparticle-facilitated functional and molecular imaging for the early detection of cancer

Emerging Biohybrids of Aptamer-Based Nano-Biosensing Technologies for Effective Early Cancer Detection

Cancer is a leading global cause of mortality, which underscores the imperative of early detection for improved patient outcomes. Biorecognition molecules, especially aptamers, have emerged as highly effective tools for early and accurate cancer cell identification. Aptamers, with superior versatility in synthesis and modification, offer enhanced binding specificity and stability compared with conventional antibodies. Hence, this article reviews diagnostic strategies employing aptamer-based biohybrid nano-biosensing technologies, focusing on their utility in detecting cancer biomarkers and abnormal cells. Recent developments include the synthesis of nano-aptamers using diverse nanomaterials, such as metallic nanoparticles, metal oxide nanoparticles, carbon-derived substances, and biohybrid nanostructures. The integration of these nanomaterials with aptamers significantly enhances sensitivity and specificity, promising innovative and efficient approaches for cancer diagnosis. This convergence of nanotechnology with aptamer research holds the potential to revolutionize cancer treatment through rapid, accurate, and non-invasive diagnostic methods.

In Situ Cancer-Cell-Triggered Visible Changes in Mechanical Properties, Electroconductivity, and Adhesiveness of a MnO2@PD-Based Mineralized Hydrogel

Herein, a cancer-specific dopamine-conjugated sp2-rich carbonized polymer dot (PD)-encapsulated mesoporous MnO2 (MnO2@PD)-mineralized hydrogel biosensor was developed that offers cancer-induced observable in situ alterations in fluorescence (FL), electrochemical, and mechanophysical properties. Cancer-triggered MnO2 degradation in the hydrogel, prompted by increased levels of glutathione (GSH) and reactive oxygen species (ROS) such as H2O2, leads to PD release and FL restoration, thereby controlling changes in the pore structure and increasing hydrogen bonding, resulting in physiologically visible alterations in mechanical stretchability, viscosity, swelling behavior, and adhesiveness. The pore size of the matrix increased from 21.83 to 36.81 m2/g upon GSH treatment, affecting the viscosity and swellability of the system. The resistance increased from 21.96 ± 1.16 to 30.69 ± 2.01 and 32.21 ± 2.54 kΩ, respectively, confirming the dependence of conductivity changes on H2O2 and GSH treatments. The in vitro treatment with cancer cells (HeLa, PC-3, and B16F10) facilitated a tunable electrochemical sensing performance via redox-mediated MnO2 breakdown by intracellular ROS and GSH, whereas hydrogels treated with normal cells (CHO-K1) showed minimal changes. Cancer-microenvironment-derived water-drop sensing showed three times higher response as compared to the normal cell-treated hydrogel. The sensing capability of the fabricated sensor was validated based on bending-induced relative resistance changes under dry and wet conditions. Moreover, the integration of the developed sensor with a wireless sensor enabled real-time monitoring with a smartphone.

Interactions of Nanoscale Self-Assembled Peptide-Based Assemblies with Glioblastoma Cell Models and Spheroids

Peptide nanoassemblies have garnered remarkable importance in the development of novel nanoscale biomaterials for drug delivery into tumor cells. Taking advantage of receptor mediated recognition of two known peptides, angiopep-2 (TFFYGGSRGKRNNFKTEEY) and A-COOP-K (ACGLSGLC10 VAK) that bind to the over-expressed receptors low density lipoprotein (LRP-1) and fatty acid binding protein (FABP3) respectively, we have developed new peptide conjugates by combining the anti-inflammatory, antitumor compound azelaic acid with angiopep-2, which efficiently self-assembled into nanofibers. Those nanofibers were then functionalized with the A-COOP-K sequence and formed supramolecular hierarchical structures that were found to entrap the chemotherapeutic drug doxorubicin efficaciously. Furthermore, the nanoassemblies were found to release the drug in a dose-dependent manner and showed a stepwise increase over a period of 2 weeks under acidic conditions. Two cell lines (U-87-MG and U-138-MG) were utilized as models for glioblastoma cells grown in the presence of serum and under serum-free conditions to mimic the growth conditions of natural tumors. The drug entrapped assemblies were found to inhibit the cell proliferation of both U-87 and U-138MG glioblastoma cells. Three dimensional spheroids of different sizes were grown to mimic the tumors and evaluate the efficacy of drug release and internalization. Our results indicated that the nanoassemblies were found to have higher internalization of DOX and were well-spread throughout the spheroids grown, particularly under serum-free conditions. The nanoassemblies also displayed blood-brain barrier penetration when tested with a multicellular in vitro model. Such self-assembled nanostructures with targeting ability may provide a suitable platform for the development of new peptide-based biomaterials that can provide more insights about the mechanistic approach for drug delivery for not only 2D cell cultures but also 3D tumoroids that mimic the tumor microenvironments.

Analysis of urine using electronic tongue towards non-invasive cancer diagnosis

Electronic tongues (e-tongues) have been broadly employed in monitoring the quality of food, beverage, cosmetics, and pharmaceutical products, and in diagnosis of diseases, as the e-tongues can discriminate samples of high complexity, reduce interference of the matrix, offer rapid response. Compared to other analytical approaches using expensive and complex instrumentation as well as required sample preparation, the e-tongue is non-destructive, miniaturizable and on-site method with little or no preparation of samples. Even though e-tongues are successfully commercialized, their application in cancer diagnosis from urine samples is underestimated. In this review, we would like to highlight the various analytical techniques such as Raman spectroscopy, infrared spectroscopy, fluorescence spectroscopy, and electrochemical methods (potentiometry and voltammetry) used as e-tongues for urine analysis towards non-invasive cancer diagnosis. Besides, different machine learning approaches, for instance, supervised and unsupervised learning algorithms are introduced to analyze extracted chemical data. Finally, capabilities of e-tongues in distinguishing between patients diagnosed with cancer and healthy controls are highlighted.

Chemotherapeutic nanomaterials in tumor boundary delineation: Prospects for effective tumor treatment

Accurately delineating tumor boundaries is key to predicting survival rates of cancer patients and assessing response of tumor microenvironment to various therapeutic techniques such as chemotherapy and radiotherapy. This review discusses various strategies that have been deployed to accurately delineate tumor boundaries with particular emphasis on the potential of chemotherapeutic nanomaterials in tumor boundary delineation. It also compiles the types of tumors that have been successfully delineated by currently available strategies. Finally, the challenges that still abound in accurate tumor boundary delineation are presented alongside possible perspective strategies to either ameliorate or solve the problems. It is expected that the information communicated herein will form the first compendious baseline information on tumor boundary delineation with chemotherapeutic nanomaterials and provide useful insights into future possible paths to advancing current available tumor boundary delineation approaches to achieve efficacious tumor therapy.

The Multifarious Applications of Copper Nanoclusters in Biosensing and Bioimaging and Their Translational Role in Early Disease Detection

Nanoclusters possess an ultrasmall size, amongst other favorable attributes, such as a high fluorescence and long-term colloidal stability, and consequently, they carry several advantages when applied in biological systems for use in diagnosis and therapy. Particularly, the early diagnosis of diseases may be facilitated by the right combination of bioimaging modalities and suitable probes. Amongst several metallic nanoclusters, copper nanoclusters (Cu NCs) present advantages over gold or silver NCs, owing to their several advantages, such as high yield, raw abundance, low cost, and presence as an important trace element in biological systems. Additionally, their usage in diagnostics and therapeutic modalities is emerging. As a result, the fluorescent properties of Cu NCs are exploited for use in optical imaging technology, which is the most commonly used research tool in the field of biomedicine. Optical imaging technology presents a myriad of advantages over other bioimaging technologies, which are discussed in this review, and has a promising future, particularly in early cancer diagnosis and imaging-guided treatment. Furthermore, we have consolidated, to the best of our knowledge, the recent trends and applications of copper nanoclusters (Cu NCs), a class of metal nanoclusters that have been gaining much traction as ideal bioimaging probes, in this review. The potential modes in which the Cu NCs are used for bioimaging purposes (e.g., as a fluorescence, magnetic resonance imaging (MRI), two-photon imaging probe) are firstly delineated, followed by their applications as biosensors and bioimaging probes, with a focus on disease detection.

Recent Advances in Gene Therapy for Cancer Theranostics

There is great interest in developing gene therapies for many disease indications, including cancer. However, successful delivery of nucleic acids to tumor cells is a major challenge, and in vivo efficacy is difficult to predict. Cancer theranostics is an approach combining anti-tumor therapy with imaging or diagnostic capabilities, with the goal of monitoring successful delivery and efficacy of a therapeutic agent in a tumor. Successful theranostics must maintain a high degree of anticancer targeting and efficacy while incorporating high-contrast imaging agents that are nontoxic and compatible with clinical imaging modalities. This review highlights recent advancements in theranostic strategies, including imaging technologies and genetic engineering approaches. Graphical Abstract.

High Channel Temperature Mapping Electronics in a Thin, Soft, Wireless Format for Non-Invasive Body Thermal Analysis

Hemodynamic status has been perceived as an important diagnostic value as fundamental physiological health conditions, including decisive signs of fatal diseases like arteriosclerosis, can be diagnosed by monitoring it. Currently, the conventional hemodynamic monitoring methods highly rely on imaging techniques requiring inconveniently large numbers of operation procedures and equipment for mapping and with a high risk of radiation exposure. Herein, an ultra-thin, noninvasive, and flexible electronic skin (e-skin) hemodynamic monitoring system based on the thermal properties of blood vessels underneath the epidermis that can be portably attached to the skin for operation is introduced. Through a series of thermal sensors, the temperatures of each subsection of the arrayed sensors are observed in real-time, and the measurements are transmitted and displayed on the screen of an external device wirelessly through a Bluetooth module using a graphical user interface (GUI). The degrees of the thermal property of subsections are indicated with a spectrum of colors that specify the hemodynamic status of the target vessel. In addition, as the sensors are installed on a soft substrate, they can operate under twisting and bending without any malfunction. These characteristics of e-skin sensors exhibit great potential in wearable and portable diagnostics including point-of-care (POC) devices.

Modeling of Anti-cancer Drug Release Kinetics from Liposomes and Micelles: A review

Nanocarriers, such as liposomes and micelles, were developed to enhance the delivery of therapeutic drugs to malignant tissues. Internal or external stimuli can be applied to achieve spatiotemporal controlled release from these carriers. This will result in enhancing their therapeutic efficacy while reducing toxicity. Mathematical modeling is used to simulate drug release from nanocarriers; this will facilitate and optimize the development and design of desirable nanocarriers in a systematic manner, rather than a trial-and-error approach. This review summarizes nine mathematical models often used to simulate drug release from nanocarriers and reviews studies which employed these models to simulate drug release from conventional as well as temperature-, pH-, and ultrasound-triggered micelles and liposomes.

Ultrasound-Responsive Nanocarriers in Cancer Treatment: A Review

The safe and effective delivery of anticancer agents to diseased tissues is one of the significant challenges in cancer therapy. Conventional anticancer agents are generally cytotoxins with poor pharmacokinetics and bioavailability. Nanocarriers are nanosized particles designed for the selectivity of anticancer drugs and gene transport to tumors. They are small enough to extravasate into solid tumors, where they slowly release their therapeutic load by passive leakage or biodegradation. Using smart nanocarriers, the rate of release of the entrapped therapeutic(s) can be increased, and greater exposure of the tumor cells to the therapeutics can be achieved when the nanocarriers are exposed to certain internally (enzymes, pH, and temperature) or externally (light, magnetic field, and ultrasound) applied stimuli that trigger the release of their load in a safe and controlled manner, spatially and temporally. This review gives a comprehensive overview of recent research findings on the different types of stimuli-responsive nanocarriers and their application in cancer treatment with a particular focus on ultrasound.

Albumin-based nanoparticles as contrast medium for MRI: vascular imaging, tissue and cell interactions, and pharmacokinetics of second-generation nanoparticles

This multidisciplinary study examined the pharmacokinetics of nanoparticles based on albumin-DTPA-gadolinium chelates, testing the hypothesis that these nanoparticles create a stronger vessel signal than conventional gadolinium-based contrast agents and exploring if they are safe for clinical use. Nanoparticles based on human serum albumin, bearing gadolinium and designed for use in magnetic resonance imaging, were used to generate magnet resonance images (MRI) of the vascular system in rats ("blood pool imaging"). At the low nanoparticle doses used for radionuclide imaging, nanoparticle-associated metals were cleared from the blood into the liver during the first 4 h after nanoparticle application. At the higher doses required for MRI, the liver became saturated and kidney and spleen acted as additional sinks for the metals, and accounted for most processing of the nanoparticles. The multiple components of the nanoparticles were cleared independently of one another. Albumin was detected in liver, spleen, and kidneys for up to 2 days after intravenous injection. Gadolinium was retained in the liver, kidneys, and spleen in significant concentrations for much longer. Gadolinium was present as significant fractions of initial dose for longer than 2 weeks after application, and gadolinium clearance was only complete after 6 weeks. Our analysis could not account quantitatively for the full dose of gadolinium that was applied, but numerous organs were found to contain gadolinium in the collagen of their connective tissues. Multiple lines of evidence indicated intracellular processing opening the DTPA chelates and leading to gadolinium long-term storage, in particular inside lysosomes. Turnover of the stored gadolinium was found to occur in soluble form in the kidneys, the liver, and the colon for up to 3 weeks after application. Gadolinium overload poses a significant hazard due to the high toxicity of free gadolinium ions. We discuss the relevance of our findings to gadolinium-deposition diseases.

Targeting of an antecedent proteinase by an activatable probe with deep tissue penetration facilitates early visualization and dynamic malignancy evaluation of orthotopic pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal and most commonly diagnosed at an advanced stage; therefore, early detection with an effective approach is vital. However, due to the anatomical stealthiness and hypovascular features of PDAC, clinically available imaging techniques lack specificity and sensitivity for early detection. As important components of the tumour microenvironment, elevated matrix metalloproteinase (MMP) levels during the early stages of tumour formation lead to tumour invasion and metastases by degrading the extracellular matrix. Thus, in the current study, we hypothesized that MMPs might be promising markers for early visualization and prognosis evaluation of PDAC. An MMP activatable probe, I₇₈₀BP-PEG12, was synthesized utilizing a long wavelength near-infrared (NIR) fluorophore that could map the dynamic development of orthotopic PDAC in vivo with deep tissue penetration. Elevated MMP activity in tumours was detected as early as 4 days after tumour transplantation. At that time, the tumour diameter was approximately 3 mm, which is much smaller than the size visualized by clinical approaches. Furthermore, much higher levels of MMP activity were detected in PDAC under diabetic conditions, which promote the malignant actions of tumours. By noninvasively monitoring MMP alteration, tumour growth, and prognostic evaluation, we found that malignant actions under diabetic conditions were reversed by inhibition of MMPs. Generally, in addition to earlier visualization of PDAC, a probe targeting MMPs can facilitate dynamic monitoring of tumour progression and inhibitory treatment in vivo, which is beneficial for personal therapeutic strategy planning and optimization of PDAC management, especially for diabetic individuals.

Current and Future Approaches for Effective Cancer Imaging and Treatment

Cancer poses a major health problem, not only due to cancer-related deaths but also because of treatment toxicities. This review discusses early diagnosis and strategies to overcome treatment difficulties, to facilitate recovery, and prevent deaths. Generally, noninvasive techniques such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission computed tomography (PET), and their hybrid systems, including SPECT/CT, PET/CT, and PET/MRI, are used in diagnosis of cancer. Cancer treatment in clinics still comprises conventional methods such as chemotherapy, radiotherapy, and surgery. However, these techniques and methods are often inadequate. Therefore, new approaches, including the formulation of actively and/or passively targeted nanosized drug delivery systems and combined treatment protocols, are being investigated. In this article, conventional cancer imaging and treatment are reviewed. In addition, the formulation of nanosized systems and their use in cancer treatment are discussed and combined diagnostic and therapeutic (theranostic) approach are proposed as additional cancer therapies.

Folate receptor-targeted ultrasonic PFOB nanoparticles: Synthesis, characterization and application in tumor-targeted imaging

In this study, we aimed to determine an effective strategy for the synthesis of folate receptor (FR) targeted-nanoparticles (FRNPs). The nanoparticles used as ultrasound contrast agents (UCAs) were composed of a liquid core of perfluorooctyl bromide (PFOB) liposome and a targeted shell chemically conjugated with folic acid (FA) and polyethylene glycol (PEG). This was done in order to avoid recognition and clearance by the mononuclear phagocyte system [also known as the reticuloendothelial system (RES)] and enhance the targeting capability of the nanoparticles to tumors overexpressing folate receptor (FR). The FRNPs exhibited an average particle size of 301±10.8 nm and surface potential of 39.1±0.43 mV. Subsequently, in vitro, FRNPs labeled with FITC fluorescence dye were visibly uptaken into the cytoplasm of FR-overexpressing cancer cells (Bel7402 and SW620 cells), whereas the A549 cells expressing relatively low levels of FR just bound with few FRNPs. These results demonstrated that FRNPs have a high affinity to FR-overexpressing cancer cells. Additionally, in in vivo experiments, FRNPs achieved a greater enhancement of tumor ultrasound imaging and a longer enhancement time in FR-overexpressing tumors and the Cy7-labeled FRNPs exhibited a relatively high tumor-targeted distribution in FR-overexpressing tumors. Targeted ultrasound and fluorescence imaging revealed that FRNPs have the ability to target FR-overexpressing tumors and ex vivo fluorescence imaging was then used to further verify and confirm the presence of FRNPs in tumor tissues with histological analysis of the tumor slices. On the whole, our data demonstrate that the FRNPs may prove to be a promising candidate for the early diagnosis for FR-overexpressing tumors at the molecular and cellular levels.

Nanoparticle-based probes to enable noninvasive imaging of proteolytic activity for cancer diagnosis

Proteases play a key role in tumor biology, with high expression levels often correlating with poor prognosis for cancer patients - making them excellent disease markers for tumor diagnosis. Despite their significance, quantifying proteolytic activity in vivo remains a challenge. Nanoparticles, with their ability to serve as scaffolds having unique chemical, optical and magnetic properties, offer the promise of merging diagnostic medicine with material engineering. Such nanoparticles can interact preferentially with proteases enriched in tumors, providing the ability to assess disease state in a noninvasive and spatiotemporal manner. We review recent advances in the development of nanoparticles for imaging and quantification of proteolytic activity in tumor models, and prognosticate future advancements.

Stimuli-Responsive Gold Nanoparticles for Cancer Diagnosis and Therapy

An emerging concept is that cancers strongly depend on both internal and external signals for growth and invasion. In this review, we will discuss pathological and physical changes in the tumor microenvironment and how these changes can be exploited to design gold nanoparticles for cancer diagnosis and therapy. These intrinsic changes include extracellular and intracellular pH, extracellular matrix enzymes, and glutathione concentration. External stimuli include the application of laser, ultrasound and X-ray. The biology behind these changes and the chemistry behind the responding mechanisms to these changes are reviewed. Examples of recent in vitro and in vivo studies are also presented, and the clinical implications of these findings are discussed.

Stimuli-Responsive Gold Nanoparticles for Cancer Diagnosis and Therapy

An emerging concept is that cancers strongly depend on both internal and external signals for growth and invasion. In this review, we will discuss pathological and physical changes in the tumor microenvironment and how these changes can be exploited to design gold nanoparticles for cancer diagnosis and therapy. These intrinsic changes include extracellular and intracellular pH, extracellular matrix enzymes, and glutathione concentration. External stimuli include the application of laser, ultrasound and X-ray. The biology behind these changes and the chemistry behind the responding mechanisms to these changes are reviewed. Examples of recent in vitro and in vivo studies are also presented, and the clinical implications of these findings are discussed.