A multifunctional mesoporous silica-gold nanocluster hybrid platform for selective breast cancer cell detection using a catalytic amplification-based colorimetric assay

Biomaterials for reliable wearable health monitoring: Applications in skin and eye integration

Recent advancements in biomaterials have significantly impacted wearable health monitoring, creating opportunities for personalized and non-invasive health assessments. These developments address the growing demand for customized healthcare solutions. Durability is a critical factor for biomaterials in wearable applications, as they must withstand diverse wearing conditions effectively. Therefore, there is a heightened focus on developing biomaterials that maintain robust and stable functionalities, essential for advancing wearable sensing technologies. This review examines the biomaterials used in wearable sensors, specifically those interfaced with human skin and eyes, highlighting essential strategies for achieving long-lasting and stable performance. We specifically discuss three main categories of biomaterials-hydrogels, fibers, and hybrid materials-each offering distinct properties ideal for use in durable wearable health monitoring systems. Moreover, we delve into the latest advancements in biomaterial-based sensors, which hold the potential to facilitate early disease detection, preventative interventions, and tailored healthcare approaches. We also address ongoing challenges and suggest future directions for research on material-based wearable sensors to encourage continuous innovation in this dynamic field.

Carboxylated mesoporous silica nanoparticle-nucleic acid chimera conjugate-assisted delivery of siRNA and doxorubicin effectively treat drug-resistant bladder cancer

Chemotherapy is the main treatment for bladder cancer, but drug resistance and side effects limit its application and therapeutic effect. Herein, we constructed doxorubicin (DOX)/COOH-mesoporous silica nanoparticle/polyethylenimine (PEI)/nucleic acid chimeras (DOX/MSN/Chimeras) to reduce the toxicity of chemotherapy drugs and the resistance of bladder cancer cells. Transmission electron microscopy showed that PEI was coated on the DOX/MSN/BSA nanoparticles with a diameter of about 150 nm. DOX/MSN/PEI could control DOX release for over 48 h, and the sudden release rate was significantly lower than DOX/MSN. Immunohistochemical results showed that DOX/MSN/Chimera specifically bound to bladder cancer cells, and markedly inhibited PI3K expression and proliferation of DOX-resistant bladder cancer cells. DOX/MSN/Chimera promoted the apoptosis of drug-resistant bladder cancer cells, which was superior to DOX/MSN/Aptamer or DOX/MSN. We further carried out animal experiments and found that DOX/MSN/Chimera could reduce the volume of transplanted tumors in vivo. Compared with DOX/MSN/Aptamer group, the proliferation rate was significantly decreased and the proportion of apoptotic cells was highly increased. Through the histological observation of kidneys and lungs, we believed that DOX/MSN/Chimera can effectively reduce the damage of chemotherapy drugs to normal tissues. In conclusion, we constructed a COOH-MSN/nucleic acid chimera conjugate for the targeted delivery of siRNA and anti-cancer drugs. Our study provides a new method for personalized and targeted treatment of drug-resistant bladder cancer.

Biomimetic Trypsin-Responsive Structure-Bridged Mesoporous Organosilica Nanomedicine for Precise Treatment of Acute Pancreatitis

Developing strategies to target injured pancreatic acinar cells (PACs) in conjunction with primary pathophysiology-specific pharmacological therapy presents a challenge in the management of acute pancreatitis (AP). We designed and synthesized a trypsin-cleavable organosilica precursor bridged by arginine-based amide bonds, leveraging trypsin's ability to selectively identify guanidino groups on arginine via Asp189 at the active S1 pocket and cleave the carboxy-terminal (C-terminal) amide bond via catalytic triads. The precursors were incorporated into the framework of mesoporous silica nanoparticles (MSNs) for encapsulating the membrane-permeable Ca2+ chelator BAPTA-AM with a high loading content (∼43.9%). Mesenchymal stem cell membrane coating and surface modification with PAC-targeting ligands endow MSNs with inflammation recruitment and precise PAC-targeting abilities, resulting in the highest distribution at 3 h in the pancreas with 4.7-fold more accumulation than that of naked MSNs. The outcomes transpired as follows: After bioinspired MSNs' skeleton biodegradation by prematurely and massively activated trypsin, BAPTA-AM was on-demand released in injured PACs, thereby effectively eliminating intracellular calcium overload (reduced Ca2+ level by 81.3%), restoring cellular redox status, blocking inflammatory cascades, and inhibiting cell necrosis by impeding the IκBα/NF-κB/TNF-α/IL-6 and CaMK-II/p-RIP3/p-MLKL/caspase-8,9 signaling pathways. In AP mice, a single dose of the formulation significantly restored pancreatic function (lipase and amylase reduced more by 60%) and improved the survival rate from 50 to 91.6%. The formulation offers a potentially effective strategy for clinical translation in AP treatment.

Biosensors for Cancer Biomarkers Based on Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles (MSNs) exhibit highly beneficial characteristics for devising efficient biosensors for different analytes. Their unique properties, such as capabilities for stable covalent binding to recognition groups (e.g., antibodies or aptamers) and sensing surfaces, open a plethora of opportunities for biosensor construction. In addition, their structured porosity offers capabilities for entrapping signaling molecules (dyes or electroactive species), which could be released efficiently in response to a desired analyte for effective optical or electrochemical detection. This work offers an overview of recent research studies (in the last five years) that contain MSNs in their optical and electrochemical sensing platforms for the detection of cancer biomarkers, classified by cancer type. In addition, this study provides an overview of cancer biomarkers, as well as electrochemical and optical detection methods in general.

Increasing the sensitivity and accuracy of detecting exosomes as biomarkers for cancer monitoring using optical nanobiosensors

The advancement of nanoscience and material design in recent times has facilitated the creation of point-of-care devices for cancer diagnosis and biomolecule sensing. Exosomes (EXOs) facilitate the transfer of bioactive molecules between cancer cells and diverse cells in the local and distant microenvironments, thereby contributing to cancer progression and metastasis. Specifically, EXOs derived from cancer are likely to function as biomarkers for early cancer detection due to the genetic or signaling alterations they transport as payload within the cancer cells of origin. It has been verified that EXOs circulate steadily in bodily secretions and contain a variety of information that indicates the progression of the tumor. However, acquiring molecular information and interactions regarding EXOs has presented significant technical challenges due to their nanoscale nature and high heterogeneity. Colorimetry, surface plasmon resonance (SPR), fluorescence, and Raman scattering are examples of optical techniques utilized to quantify cancer exosomal biomarkers, including lipids, proteins, RNA, and DNA. Many optically active nanoparticles (NPs), predominantly carbon-based, inorganic, organic, and composite-based nanomaterials, have been employed in biosensing technology. The exceptional physical properties exhibited by nanomaterials, including carbon NPs, noble metal NPs, and magnetic NPs, have facilitated significant progress in the development of optical nanobiosensors intended for the detection of EXOs originating from tumors. Following a summary of the biogenesis, biological functions, and biomarker value of known EXOs, this article provides an update on the detection methodologies currently under investigation. In conclusion, we propose some potential enhancements to optical biosensors utilized in detecting EXO, utilizing various NP materials such as silicon NPs, graphene oxide (GO), metal NPs, and quantum dots (QDs).

Multienzyme-Like Nanozymes: Regulation, Rational Design, and Application

Nanomaterials with more than one enzyme-like activity are termed multienzymic nanozymes, and they have received increasing attention in recent years and hold huge potential to be applied in diverse fields, especially for biosensing and therapeutics. Compared to single enzyme-like nanozymes, multienzymic nanozymes offer various unique advantages, including synergistic effects, cascaded reactions, and environmentally responsive selectivity. Nevertheless, along with these merits, the catalytic mechanism and rational design of multienzymic nanozymes are more complicated and elusive as compared to single-enzymic nanozymes. In this review, the multienzymic nanozymes classification scheme based on the numbers/types of activities, the internal and external factors regulating the multienzymatic activities, the rational design based on chemical, biomimetic, and computer-aided strategies, and recent progress in applications attributed to the advantages of multicatalytic activities are systematically discussed. Finally, current challenges and future perspectives regarding the development and application of multienzymatic nanozymes are suggested. This review aims to deepen the understanding and inspire the research in multienzymic nanozymes to a greater extent.

Challenges and Opportunities of Using Fluorescent Metal Nanocluster-Based Colorimetric Assays in Medicine

Development of rapid colorimetric methods based on novel optical-active metal nanomaterials has provided methods for the detection of ions, biomarkers, cancers, etc. Fluorescent metal nanoclusters (FMNCs) have gained a lot of attention due to their unique physical, chemical, and optical properties providing numerous applications from rapid and sensitive detection to cellular imaging. However, because of very small color changes, their colorimetric applications for developing rapid tests based on the naked eye or simple UV-vis absorption spectrophotometry are still limited. FMNCs with peroxidase-like activity have significant potential in a wide variety of applications, especially for point-of-care diagnostics. In this review, the effect of using various capping agents and metals for the preparation of nanoclusters in their colorimetric sensing properties is explored, and the synthesis and detection mechanisms and the recent advances in their application for ultrasensitive chemical and biological analysis regarding human health are highlighted. Finally, the challenges that remain as well as the future perspectives are briefly discussed. Overcoming these limitations will allow us to expand the nanocluster's application for colorimetric diagnostic purposes in medical practice.

Silicon-Carbon Dots-Loaded Mesoporous Silica Nanocomposites (mSiO2@SiCDs): An Efficient Dual Inhibitor of Cu2+-Mediated Oxidative Stress and Aβ Aggregation for Alzheimer's Disease

The redox-active metal ions, especially Cu2+, are highly correlated to Alzheimer's disease (AD) by causing metal ion-mediated oxidative stress and toxic metal-bound β-amyloid (Aβ) aggregates. Numerous pieces of evidence have revealed that the regulation of metal homeostasis could be an effective therapeutic strategy for AD. Herein, in virtue of the interaction of both amino-containing silane and ethylenediaminetetraacetic acid disodium salt for Cu2+, the silicon-carbon dots (SiCDs) are deliberately prepared using these two raw materials as the cocarbon source; meanwhile, to realize the local enrichment of SiCDs and further maximize the chelating ability to Cu2+, the SiCDs are feasibly loaded to the biocompatible mesoporous silica nanoparticles (mSiO2) with the interaction between residual silane groups on SiCDs and silanol groups of mSiO2. Thus-obtained nanocomposites (i.e., mSiO2@SiCDs) could serve as an efficient Cu2+ chelator with satisfactory metal selectivity and further modulate the enzymic activity of free Cu2+ and the Aβ42-Cu2+ complex to alleviate the pathological oxidative stress with an anti-inflammatory effect. Besides, mSiO2@SiCDs show an inspiring inhibitory effect on Cu2+-mediated Aβ aggregation and further protect the neural cells against the toxic Aβ42-Cu2+ complex. Moreover, the transgenic Caenorhabditis elegans CL2120 assay demonstrates the protective efficacy of mSiO2@SiCDs on Cu2+-mediated Aβ toxicity in vivo, indicating its potential for AD treatment.

Toxicological Profiling and Long-Term Effects of Bare, PEGylated- and Galacto-Oligosaccharide-Functionalized Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles (MSNs) are amongst the most used nanoparticles in biomedicine. However, the potentially toxic effects of MSNs have not yet been fully evaluated, being a controversial matter in research. In this study, bare MSNs, PEGylated MSNs (MSNs-PEG), and galacto-oligosaccharide-functionalized MSNs (MSNs-GAL) are synthesized and characterized to assess their genotoxicity and transforming ability on human lung epithelial BEAS-2B cells in short- (48 h) and long-term (8 weeks) exposure scenarios. Initial short-term treatments show a dose-dependent increase in genotoxicity for MSNs-PEG-treated cells but not oxidative DNA damage for MSNs, MSNs-PEG, or for MSNs-GAL. In addition, after 8 weeks of continuous exposure, neither induced genotoxic nor oxidative DNA is observed. Nevertheless, long-term treatment with MSNs-PEG and MSNs-GAL, but not bare MSNs, induces cell transformation features, as evidenced by the cell's enhanced ability to grow independently of anchorage, to migrate, and to invade. Further, the secretome from cells treated with MSNs and MSNs-GAL, but not MSNs-PEG, shows certain tumor-promoting abilities, increasing the number and size of HeLa cell colonies formed in the indirect soft-agar assay. These results show that MSNs, specifically the functionalized ones, provoke some measurable adverse effects linked to tumorigenesis. These effects are in the order of other nanomaterials, such as carbon nanotubes or cerium dioxide nanoparticles, but they are lower than those provoked by some approved drugs, such as doxorubicin or dexamethasone.

Nanoparticle-Based Artificial Mitochondrial DNA Transcription Regulator: MitoScript

The growing knowledge of the links between aberrant mitochondrial gene transcription and human diseases necessitates both an effective and dynamic approach to control mitochondrial DNA (mtDNA) transcription. To address this challenge, we developed a nanoparticle-based synthetic mitochondrial transcription regulator (MitoScript). MitoScript provides great colloidal stability, excellent biocompatibility, efficient cell uptake, and selective mitochondria targeting and can be monitored in live cells using near-infrared fluorescence. Notably, MitoScript controlled mtDNA transcription in a human cell line in an effective and selective manner. MitoScript targeting the light strand promoter region of mtDNA resulted in the downregulation of ND6 gene silencing, which eventually affected cell redox status, with considerably increased reactive oxygen species (ROS) generation. In summary, we developed MitoScript for the efficient, nonviral modification of mitochondrial DNA transcription. Our platform technology can potentially contribute to understanding the fundamental mechanisms of mitochondrial disorders and developing effective treatments for mitochondrial diseases.

Nanomaterials for Fluorescence and Multimodal Bioimaging

Bioconjugated nanomaterials replace molecular probes in bioanalysis and bioimaging in vitro and in vivo. Nanoparticles of silica, metals, semiconductors, polymers, and supramolecular systems, conjugated with contrast agents and drugs for image-guided (MRI, fluorescence, PET, Raman, SPECT, photodynamic, photothermal, and photoacoustic) therapy infiltrate into preclinical and clinical settings. Small bioactive molecules like peptides, proteins, or DNA conjugated to the surfaces of drugs or probes help us to interface them with cells and tissues. Nevertheless, the toxicity and pharmacokinetics of nanodrugs, nanoprobes, and their components become the clinical barriers, underscoring the significance of developing biocompatible next-generation drugs and contrast agents. This account provides state-of-the-art advancements in the preparation and biological applications of bioconjugated nanomaterials and their molecular, cell, and in vivo applications. It focuses on the preparation, bioimaging, and bioanalytical applications of monomodal and multimodal nanoprobes composed of quantum dots, quantum clusters, iron oxide nanoparticles, and a few rare earth metal ion complexes.

A novel biosensing platform for detection of glaucoma biomarker GDF15 via an integrated BLI-ELASA strategy

Glaucoma is a leading cause of irreversible blindness worldwide. Early discovery and prioritized intervention significantly impact its prognosis. Precise monitoring of the biomarker GDF15 contributes towards effective diagnosis and assessment of glaucoma. In this study, we demonstrate that GDF15 monitoring can also aid screening for glaucoma risk and early diagnosis. We obtained an aptamer (APT2TM) with high affinity, high specificity, and high stability for binding to both human-derived and rat-derived GDF15. Simulation results showed that the binding capabilities of APT2TM are mainly affected by the interplay between van der Waals forces and polar solvation energy, and that salt bridges and hydrogen bonds play critical roles. We then integrated an enzyme-linked aptamer sandwich assay (ELASA) into a biolayer interferometry (BLI) system to develop an automated, high-throughput, real-time monitoring BLI-ELASA biosensing platform. This platform exhibited a wide linear detection window (10-810 pg/mL range) and high sensitivity for GDF15 (detection limit of 5-6 pg/mL). Moreover, we confirmed its excellent performance when applied to GDF15 quantification in real samples from glaucomatous rats and clinical patients. We believe that this technology represents a robust, convenient, and cost-effective approach for risk screening, early diagnosis, and animal modeling evaluation of glaucoma in the near future.

Porphyrin-Based Covalent Organic Frameworks with Donor-Acceptor Structure for Enhanced Peroxidase-like Activity as a Colorimetric Biosensing Platform

Hydrogen peroxide (H₂O₂) and glucose play a key role in many cellular signaling pathways. The efficient and accurate in situ detection of H₂O₂ released from living cells has attracted extensive research interests. Herein, a new porphyrin-based porous covalent organic framework (TAP-COF) was fabricated via one-step condensation of 1,6,7,12-tetrachloroperylene tetracarboxylic acid dianhydride and 5,10,15,20-tetrakis (4-aminophenyl)porphyrin iron(III). The obtained TAP-COF has high surface areas, abundant surface catalytic active sites, and highly effective electron transport due to its precisely controllable donor-acceptor arrangement and 3D porous structure. Then, the new TAP-COF exhibited excellent peroxidase-like catalytic activity, which could effectively catalyze oxidation of the substrate 3,3',5,5'-tetramethylbenzidine by H₂O₂ to produce a typical blue-colored reaction. On this basis, simple, rapid and selective colorimetric methods for in situ H₂O₂ detection were developed with the detection limit of 2.6 nM in the wide range of 0.01 to 200 μM. The colorimetric approach also could be used for in situ detection of H₂O₂ released from living MCF-7 cells. This portable sensor based on a COF nanozyme not only opens a new path for point-of-care testing, but also has potential applications in the field of cell biology and clinical diagnosis.

An Oligopeptide-Protected Ultrasmall Gold Nanocluster with Peroxidase-Mimicking and Cellular-Imaging Capacities

Recent decades have witnessed the rapid progress of nanozymes and their high promising applications in catalysis and bioclinics. However, the comprehensive synthetic procedures and harsh synthetic conditions represent significant challenges for nanozymes. In this study, monodisperse, ultrasmall gold clusters with peroxidase-like activity were prepared via a simple and robust one-pot method. The reaction of clusters with H₂O₂ and 3,3',5,5'-tetramethylbenzidine (TMB) followed the Michaelis-Menton kinetics. In addition, in vitro experiments showed that the prepared clusters had good biocompatibility and cell imaging ability, indicating their future potential as multi-functional materials.

Gold nanoparticles: current and upcoming biomedical applications in sensing, drug, and gene delivery

Gold nanoparticles (AuNPs) present unique physicochemical characteristics, low cytotoxicity, chemical stability, size/morphology tunability, surface functionalization capability, and optical properties which can be exploited for detection applications (colorimetry, surface-enhanced Raman scattering, and photoluminescence). The current challenge for AuNPs is incorporating these properties in developing more sensible and selective sensing methods and multifunctional platforms capable of controlled and precise drug or gene delivery. This review briefly highlights the recent progress of AuNPs in biomedicine as bio-sensors and targeted nano vehicles.

Bovine serum albumin-gold nanoclusters protein corona stabilized polystyrene nanoparticles as dual-color fluorescent nanoprobes for breast cancer detection

Breast cancer is the most prevalent malignancy and the first leading cause of cancer-related mortality among the female population worldwide. Approaches for precise and reliable detection of breast cancer cells, particularly in the nascent state, are desperately needed for elevating the survival rate of patients bearing the breast tumor. In this work, we successfully performed the sensitive, precise, and reliable breast cancer cell detection using facilely fabricated bovine serum albumin-gold nanocluster (BSA-AuNCs) protein corona stabilized, epithelial cell adhesion molecule (EpCAM) aptamer linked fluorescent polystyrene nanoparticle (PS NP), termed as PS-BSA-AuNCs-Apt. The rapidly adsorbed BSA-AuNCs hard protein corona without complicated covalent conjugation not only imparted excellent colloidal stability to the PS nanoparticles, but also offered numerous active anchors for the targeted EpCAM aptamers to locate. With the remarkable aid of the aptamers specifically targeting the EpCAM-positive breast cancer cells, the PS-BSA-AuNCs-Apt emitted strong and photostable dual-color fluorescent signals for precise and reliable cancer cell detection by overcoming the false signals. The specific identification potency of the PS-BSA-AuNCs-Apt system was further verified by successfully detecting the xenografted breast tumor tissue. Notably, to the best of our knowledge, the protein corona formed nanoprobes was exploited for direct tumor cell and tissue detection with high efficacy for the first time, demonstrating their promising potential in clinical tumor detection.

AuPt Bimetallic Nanozymes for Enhanced Glucose Catalytic Oxidase

Au metal nanoparticles as artificial nanozymes have attracted wide interest in biotechnology due to high stability and easy synthesis. Unfortunately, its catalytic activity is limited by the uniform surface electron distribution, fundamentally affecting the oxidation efficiency of glucose. Here, we synthesized AuPt bimetallic nanoparticles with unique surface electron structure due to the coupling effect of the two metal components, achieving improved glucose catalytic oxidase. Because of the effective work function difference between the two metals in AuPt, the electrons will transfer from Au to accumulate on Pt, simultaneously contributing to the substantial enhancement of Au-induced glucose oxidase and Pt-induced catalase performance. We systematically studied the enzyme-catalytic efficiency of AuPt with varied two metal proportions, in which Au:Pt at 3:1 showed the highest catalytic efficiency of glucose oxidase in solution. The AuPt nanoparticles were further co-cultured with cells and also showed excellent biological activity for glucose oxidase. This work demonstrates that the physicochemical properties between different metals can be exploited for engineering high-performance metal nanoparticle-based nanozymes, which opens up a new way to rationally design and optimize artificial nanozymes to mimic natural enzymes.

A new recognition moiety diphenylborinate in the detection of pyruvate via Lewis acid/base sensing pathway and its bioimaging applications

Developing new reaction based recognizing units can enhance the specificity of target analyte molecules in practical applications of real samples and biosystems. Therefore, introducing a recognizing moiety diphenylborinate was encountered for the detection of pyruvate biomolecule through Lewis acid-base reaction based sensing strategy. The construction of the Schiff-base back bone between quinoline and N-(diethylamino)salicylaldehyde-diphenylborinate (QSB) were expressed the red shift from blue emission of quinoline in to green as that of dative bond developed between Schiff base nitrogen and boron atoms. The new sensing approach was involved such a way that fluorophore QSB is a Lewis acid while pyruvate acts as Lewis base, where the elimination of Lewis pair produced a weak green fluorescence including the formation of quinoline, N-(diethylamino)salicylaldehyde (QS). The switching products were witnessed through ¹H NMR titration, HR-MS and FT-IR studies. The good selectivity and interference ability were achieved in presence of 1000-fold excess of possible interferences with LOD of 16 nM. Moreover, the tracking ability of the probe was employed towards pyruvate in live HeLa cell imaging for evaluating an exogenous and endogenous signals producing ability and its mitochondria targeting property was investigated successfully. Further, the practical utility of the probe was tested with milk samples and obtained good recovery results.

Optical cytosensors for the detection of circulating tumour cells

Blood analysis is an established approach to monitor various diseases, ranging from heart defects and diabetes to cancer. Among various tumor markers in the blood, circulating tumor cells (CTCs) have received increasing attention due to the fact that they originate directly from the tumors. Capturing and detecting CTCs represents a promising approach in cancer diagnostics and clinical management of cancers. CTCs in blood progress to self-seeding a tumour or initiating a new lesion mass. Cytosensors are biosensors intended to identify CTCs in a blood sample of cancer patients and provide information about the cancer status. Herein, we firstly discuss different detection methods of state-of-the-art optical cytosensors, including colorimetry, fluorescence, surface plasmon resonance, photoelectrochemistry and electrochemiluminescence. Then we review the significant advances made in implementing biorecognition elements and nanomaterials for the detection of cancer cells. Despite great progress in optical cytosensors, and their integration with smartphones, they have still only been explored to prototype stages. Much more effort is needed to fulfil their potential in modern cancer diagnostics and in monitoring the state of disease for cancer patients.

Cell membrane-coated nanoparticles as peroxidase mimetics for cancer cell targeted detection and therapy

The development of novel and efficient recognition molecules that can be easily modified by nanomaterials to achieve ultra-sensitive and specific cancer cell analysis is of great significance for its early diagnosis and timely prognosis. Herin, a new nanostructured hybrid based on cell membrane-coated Au cores- ultrathin Pt skins composite nanoparticles (Au@Pt@CM NPs) were developed for in vitro detection and treatment of cancer cells. In this strategy, the Au@Pt NPs acted as the signal transducer, and the cell membrane were used as the cancer-cell recognition tool. The synthesized Au@Pt@CM NPs could catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of the hydrogen peroxide and were demonstrated to have excellent peroxidase-like activity. Coated with the source cancer cell membrane, the nanoparticles achieved highly specific self-recognition to the source cell. Therefore, the colorimetric method based on Au@Pt@CM NPs could detect the cancer cells in the linear range from 50 to 100000 cells/mL with a limit of detection of 5 cells/mL, which is much lower than other colorimetric detection methods. Afterwards, the nanoparticles as a mimetic enzyme were used for therapeutics of cancer cells through the ROS-mediated oxidative damage. Due to the change of the redox state in the cells by the Au@Pt@CM NPs, the hybrid can achieve the growth inhibitory effect and the selective killing effect on cancer cells. It can be expected that this novel hybrid membrane coating method will bring new insight into developing targeted nanomaterials for tumor treatment and detection.

CRISPR-Cas12a-regulated DNA adsorption and metallization on MXenes as enhanced enzyme mimics for sensitive colorimetric detection of hepatitis B virus DNA

Hepatitis B virus (HBV) infection is closely associated with the high risk of evolving into human hepatitis diseases including chronic hepatitis, liver fibrosis and cirrhosis, as well as hepatoma. Although various methods have been developed for HBV DNA detection, most of them either rely on expensive instruments or laborious procedures involving professional personnel. In this study, we for the first time established the CRISPR-Cas12a based colorimetric biosensor for target HBV detection by utilizing probe DNA regulation of the catalytic behaviors of Mxene-probe DNA-Ag/Pt nanohybrids. In the presence of HBV target, the Cas12a trans-cleavage activity could be efficiently activated to degrade the DNA probes, which led to the inhibition of DNA metallization and enzyme activity enhancer DNA adsorbed on Mxene, resulting in significantly reduced catalytic activity. The Mxene-probe DNA-Ag/Pt nanohybrids exhibited excellent sensitivity and specificity with subpicomolar detection limits, as well as good accuracy and stability for the determination of target HBV DNA in human serum samples. Moreover, this colorimetric sensing strategy could be integrated with the smartphone platform to allow the visible sensitive detection of target DNA. Taken together, the proposed colorimetric method provides a novel approach for HBV DNA diagnosis, especially suitable for the high endemic, developing countries with limited instrumental and medical supports.

Recent advances in nanomaterials for prostate cancer detection and diagnosis

Despite the significant progress in the discovery of biomarkers and the exploitation of technologies for prostate cancer (PCa) detection and diagnosis, the initial screening of these PCa-related biomarkers using current...

Optimization of the GSH-Mediated Formation of Mesoporous Silica-Coated Gold Nanoclusters for NIR Light-Triggered Photothermal Applications

Cancer light-triggered hyperthermia mediated by nanomaterials aims to eliminate cancer cells by inducing localized temperature increases to values superior to 42 °C, upon irradiation with a laser. Among the different nanomaterials with photothermal capacity, the gold-based nanoparticles have been widely studied due to their structural plasticity and advantageous physicochemical properties. Herein, a novel and straightforward methodology was developed to produce gold nanoclusters coated with mesoporous silica (AuMSS), using glutathione (GSH) to mediate the formation of the gold clusters. The obtained results revealed that GSH is capable of triggering and control the aggregation of gold nanospheres, which enhanced the absorption of radiation in the NIR region of the spectra. Moreover, the produced AuMSS nanoclusters mediated a maximum temperature increase of 20 °C and were able to encapsulate a drug model (acridine orange). In addition, these AuMSS nanoclusters were also biocompatible with both healthy (fibroblasts) and carcinogenic (cervical cancer) cells, at a maximum tested concentration of 200 μg/mL. Nevertheless, the AuMSS nanoclusters’ NIR light-triggered heat generation successfully reduced the viability of cervical cancer cells by about 80%. This confirms the potential of the AuMSS nanoclusters to be applied in cancer therapy, namely as theragnostic agents.

Spatiotemporal control of CRISPR/Cas9 gene editing

The clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) gene editing technology, as a revolutionary breakthrough in genetic engineering, offers a promising platform to improve the treatment of various genetic and infectious diseases because of its simple design and powerful ability to edit different loci simultaneously. However, failure to conduct precise gene editing in specific tissues or cells within a certain time may result in undesirable consequences, such as serious off-target effects, representing a critical challenge for the clinical translation of the technology. Recently, some emerging strategies using genetic regulation, chemical and physical strategies to regulate the activity of CRISPR/Cas9 have shown promising results in the improvement of spatiotemporal controllability. Herein, in this review, we first summarize the latest progress of these advanced strategies involving cell-specific promoters, small-molecule activation and inhibition, bioresponsive delivery carriers, and optical/thermal/ultrasonic/magnetic activation. Next, we highlight the advantages and disadvantages of various strategies and discuss their obstacles and limitations in clinical translation. Finally, we propose viewpoints on directions that can be explored to further improve the spatiotemporal operability of CRISPR/Cas9.

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

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

Red-light-responsive coordination polymers nanorods: New strategy for ultrasensitive photothermal detection of targeted cancer cells

The development of highly sensitive and simple detection methods for cancer cells is an important challenge to achieve early cancer diagnosis and effective treatment. In this paper, folic acid (FA)-conjugated platinum (IV) methylene blue (MB) coordination polymers nanorods (denoted as FA-PtCPs NRs) were developed by the photochemical method. The structure of the PtCPs NRs was investigated using the meta-dynamics and genetic algorithms (MTD-GC) method, and it was found that the coordination bond was formed between platinum (IV) and N atoms of MB. The field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) indicated that the morphology of PtCPs NRs was rod-like. The resulting FA-PtCPs NRs was used for the specific and ultra-sensitive temperature detection of cancer cells based on PtCPs NRs as a signal trigger unit and FA as a target recognition tool. After three-step reaction, oxidized 3,3',5,5'-tetramethylbenzidine (ox-TMB) with photothermal effect was obtained. Under 660 nm laser irradiation, such detection platform can convert the molecular recognition signal between FA and folate receptor (FR) of cancer cells into readable temperature value, which can be directly read by an ordinary thermometer, with a detection limit as low as 2 cells/mL. In addition, FA-PtCPs NRs could be used as fluorescent probes for in-situ bioimaging. Therefore, this photothermal sensing platform has a broad prospect in the field of point-of-care detection of cancer cells.

Diagnosis of cancer at early stages based on the multiplex detection of tumor markers using metal nanoclusters

Traditional cancer diagnosis strategies are not considered by most people until the last resort, which delays many cancer treatments leading to advanced stages. Tumor marker sensors show great potential for detecting cancer because of its cost-effective and harmless checking procedures. Normally, one tumor marker is detected each time by using one type of sensor, but the accuracy to declare cancer is not always satisfied. Metal nanoclusters are ultra-small nanomaterials with low toxicity, distinct optical properties, catalytic activities, and cost-effective performance. Some metal nanoclusters have been designed to detect more than one tumor marker in a single step. The consideration of combined parameters using such facile sensing strategies has the potential to simplify the test procedure, and increase the diagnostic accuracy of early cancer. Therefore, various sensing strategies for the multiplex detection of tumor markers using metal nanoclusters are summarized.

Engineering Nano-Therapeutics to Boost Adoptive Cell Therapy for Cancer Treatment

Although adoptive transfer of therapeutic cells to cancer patients is demonstrated with great success and fortunately approved for the treatment of leukemia and B-cell lymphoma, potential issues, including the unclear mechanism, complicated procedures, unfavorable therapeutic efficacy for solid tumors, and side effects, still hinder its extensive applications. The explosion of nanotechnology recently has led to advanced development of novel strategies to address these challenges, facilitating the design of nano-therapeutics to improve adoptive cell therapy (ACT) for cancer treatment. In this review, the emerging nano-enabled approaches, that design multiscale artificial antigen-presenting cells for cell proliferation and stimulation in vitro, promote the transducing efficiency of tumor-targeting domains, engineer therapeutic cells for in vivo imaging, tumor infiltration, and in vivo functional sustainability, as well as generate tumoricidal T cells in vivo, are summarized. Meanwhile, the current challenges and future perspectives of the nanostrategy-based ACT for cancer treatment are also discussed in the end.

Magnetism, Ultrasound, and Light-Stimulated Mesoporous Silica Nanocarriers for Theranostics and Beyond

Stimuli-responsive multifunctional mesoporous silica nanoparticles (MSNs) have been studied intensively during the past decade. A large variety of mesopore capping systems have been designed, initially to show that it could be done and later for biomedical applications such as drug delivery and imaging. On-command release of cargo molecules such as drugs from the pores can be activated by a variety of stimuli. This paper focuses on three noninvasive, biologically usable external stimuli: magnetism, ultrasound, and light. We survey the variety of MSNs that have been and are being used and assess capping designs and the advantages and drawbacks of the nanoplatforms' responses to the various stimuli. We discuss important recent advances, their basic mechanisms, and their requirements for stimulation. On the basis of our survey, we identify fundamental challenges and suggest future directions for research that will unleash the full potential of these fascinating nanosystems for clinical applications.

In vivo guiding inorganic nanozymes for biosensing and therapeutic potential in cancer, inflammation and microbial infections

Researchers have recently introduced some artificial enzymes based on nanomaterials that show significant catalytic activity relative to native enzymes called nanozyme. These nanozymes show superior performance than conventional catalysts and are considered as fascinating candidates for introducing the next generation of biomaterials in various industrial and biomedical fields. Recently, nanozymes have received a great deal of attention in biomedical applications due to their potential properties such as long-term stability, low cost, mass production capability, and controllable catalytic activity. Due to the intrinsic catalytic activity of nanoparticles (NPs) as nanozymes and their ability to be regulated in biomedical processes, this review paper focuses on the in vivo applications of nanozymes in biosensing and therapeutic activities. Despite the challenges and benefits of each approach, this paper attempts to provide an appropriate motivation for the classification of different nanozymes followed by their application in biomedical activities including in vivo biosensing and therapeutic potential in cancer, inflammation and microbial infections. Finally, some ongoing challenges and future perspective of nanozymes in biomedical application were surveyed. In conclusion, this paper may provide useful information regarding the development of nanozymes as promising platforms in biomedical settings due to expedited diagnosis, the advancement of multifactorial therapies and their pronounced stability.

Mesoporous Materials-Based Electrochemical Biosensors from Enzymatic to Nonenzymatic

Mesoporous materials have drawn more and more attention in the field of biosensors due to their high surface areas, large pore volumes, tunable pore sizes, as well as abundant frameworks. In this review, the progress on mesoporous materials-based biosensors from enzymatic to nonenzymatic are highlighted. First, recent advances on the application of mesoporous materials as supports to stabilize enzymes in enzymatic biosensing technology are summarized. Special emphasis is placed on the effect of pore size, pore structure, and surface functional groups of the support on the immobilization efficiency of enzymes and the biosensing performance. Then, the development of a nonenzymatic strategy that uses the intrinsic property of mesoporous materials (carbon, silica, metals, and composites) to mimic the behavior of enzymes for electrochemical sensing of some biomolecules is discussed. Finally, the challenges and perspective on the future development of biosensors based on mesoporous materials are proposed.

Rare-Earth Eu3+/Gold Nanocluster Ensemble-Based Fluorescent Photoinduced Electron Transfer Sensor for Biomarker Dipicolinic Acid Detection

The use of metal ions to bridge the fluorescent materials to target analytes has been demonstrated to be a promising way to sensor design. Herein, the effect of rare-earth ions on the fluorescence of l-methionine-stabilized gold nanoclusters (Met-AuNCs) was investigated. It was found that europium (Eu³⁺) can significantly suppress the emission of Met-AuNCs, while other rare-earth ions showed a negligible impact. The mechanism on the observed fluorescence quenching of Met-AuNCs triggered by Eu³⁺ was systematically explored, with results revealing the dominant role of photoinduced electron transfer (PET). Eu³⁺ can bind to the surface of Met-AuNCs by the coordination effect and accepts the electron from the excited Met-AuNCs, which results in Met-AuNC fluorescence suppression. After introducing dipicolinic acid (DPA), an excellent biomarker for spore-forming pathogens, Eu³⁺ was removed from the surface of Met-AuNCs owing to the higher binding affinity between Eu³⁺ and DPA. Consequently, an immediate fluorescence recovery occurred when DPA was present in the system. Based on the Met-AuNC/Eu³⁺ ensemble, we then established a simple and sensitive fluorescence strategy for turn-on determination of biomarker DPA, with a linear range of 0.2-4 μM and a low limit of detection of 110 nM. The feasibility of the proposed method was further validated by the quantitative detection of DPA in the soil samples. We believe that this study would significantly facilitate the construction of metal-ion-mediated PET sensors for the measurement of various interested analytes by applying fluorescent AuNCs as detection probes.

Recent advances in nanomaterials for colorimetric cancer detection

The early diagnosis of cancer can significantly improve patient survival rates. Colorimetric methods for real-time naked-eye detection have aroused growing interest owing to their low cost, simplicity, and practicability. With the rapid development of nanotechnology, compared with conventional diagnostic methods, nanomaterials with unique physical and chemical properties were applied to improve selectivity and sensitivity in colorimetric detection of cancer biomarkers, such as MUC1 aptamer conjugated PtAuNPs to specifically recognize MUC1 proteins on the cancer cell surfaces, etching of silver nanoprisms to detect prostate-specific antigen, and aggregation or dispersion of AuNPs to sense prostate cancer antigen gene 3 or glutathione, by which the limit of detection (LOD) could approach values down to a few cancer cells per mL, several fg per mL proteins, several ng of nucleic acids, or even tens of nM of organic molecules. Herein, we review the recent progress achieved in developing colorimetric nanosensors for cancer diagnosis, particularly providing an overview of the sensing principles, target biomarkers, advanced nanomaterials employed in the fabrication of sensing platforms, and strategies for improving signal sensitivity and specificity. Finally, we sum up the nanomaterial-based colorimetric cancer detection as well as existing challenges that should be resolved to extend their clinical application.

Cu2O nanocubes-grafted highly dense Au nanoparticles with modulated electronic structures for improving peroxidase catalytic performances

Based on the intermediate states of metal ions in metal oxide nanomaterials (NMs) that acted as the primary active species, the design of high-performance nanozymes has greatly stimulated current research in diverse biomedical applications. Herein, Cu₂O nanocubes-grafted highly dense Au nanoparticles (NPs) was developed as an appealing nanozyme for H₂O₂ colorimetric sensor and antioxidant detections. The obtained Au/Cu₂O heterostructures show efficient electron-transfer from metallic NPs to Cu₂O nanocubes owing to the difference of Fermi energy between two components. The modulated electronic structure of Au/Cu₂O hybrids enables them to possess enhanced peroxidase catalytic activity for the oxidation of 3, 3', 5, 5'-tetramethylbenzidine (TMB) in the presence of H₂O₂, which is about 32% higher than that of pristine Cu₂O nanocubes. Then, an excellent H₂O₂ colorimetric sensor was established by using Au/Cu₂O heterostructures with a low limit of detection (LOD) of 0.054 μM, which is much lower than the H₂O₂ allowance level of US FDA regulations (ca.15 μM, 0.05 wt%). The obtained Au/Cu₂O nanoproducts exhibit pronounced long-time stability with 95% peroxidase activity maintained after keeping them for 30 days, while residual 64.5% via Cu₂O nanocubes. Furthermore, we assessed the anti-oxidative behavior of three natural antioxidants (tannic acid, gallic acid, tartaric acid) with the LODs as low as 0.039, 0.16 and 1.55 μM, respectively, and the antioxidant capacity in the following order: tannic acid > gallic acid > tartaric acid. Therefore, it is believed that the as-prepared Au/Cu₂O nanozymes have promising potential applications in fields of biomedicine and food safety.

Applications of Nanobiomaterials in the Therapy and Imaging of Acute Liver Failure

This review focuses on the therapeutic mechanisms, targeting strategies of various nanomaterials in acute liver failure, and recent advances of diverse nanomaterials for acute liver failure therapy, diagnosis, and imaging. This review provides an outlook on the applications of nanomaterials, especially on the new horizons in acute liver failure therapy, and inspires broader interests across various disciplines. Acute liver failure (ALF), a fatal clinical disease featured with overwhelming hepatocyte necrosis, is a grand challenge in global health. However, a satisfactory therapeutic option for curing ALF is still absent, other than liver transplantation. Nanobiomaterials are currently being developed for the diagnosis and treatment of ALF. The liver can sequester most of nanoparticles from blood circulation, which becomes an intrinsic superiority for nanobiomaterials targeting hepatic diseases. Nanobiomaterials can enhance the bioavailability of free drugs, thereby significantly improving the therapeutic effects in ALF. Nanobiomaterials can also increase the liver accumulation of therapeutic agents and enable more effective targeting of the liver or specific liver cells. In addition, stimuli-responsive, optical, or magnetic nanomaterials exhibit great potential in the therapeutical, diagnostic, and imaging applications in ALF. Therefore, therapeutic agents in combination with nanobiomaterials increase the specificity of ALF therapy, diminish adverse systemic effects, and offer a multifunctional theranostic platform. Nanobiomaterial holds excellent significance and prospects in ALF theranostics. In this review, we summarize the therapeutic mechanisms and targeting strategies of various nanobiomaterials in ALF. We highlight recent developments of diverse nanomedicines for ALF therapy, diagnosis, and imaging. Furthermore, the challenges and future perspectives in the theranostics of ALF are also discussed.

Norfloxacin detection based on the peroxidase-like activity enhancement of gold nanoclusters

The use of nanomaterials as mimic enzymes provides a promising way to implement bio-molecule detection in living systems. However, to achieve highly efficient catalytic processes with gold nanocluster-based nanozymes is still challenging. In this study, a facile reduction method was utilized to synthesize gold nanoclusters with 1-methyl-D-tryptophan as the reducing and capping agent. The obtained gold nanoclusters exhibited a peroxidase-mimicking property in the redox reaction of 3,3',5,5'-tetramethylbenzidine to blue oxidized 3,3',5,5'-tetramethylbenzidine in the presence of H₂O₂. The addition of norfloxacin endowed the nanozymes with a 10-fold enhancement in catalytic efficiency due to the surface charge-controlled electron transfer modulation. The colorimetric sensing system presented a high selectivity toward norfloxacin. The good linear relationship of norfloxacin monitoring was gained in the range of 1.25~8.0 μM (R² = 0.996), with a detection limit of 0.2 μM. The practical application of the proposed protocol for the measurement of norfloxacin in capsules was realized. This demonstrates that on account of their significant catalytic efficiency enhancement, the gold nanocluster-based nanozymes hold great promise in realizing the selective detection of drugs. Graphical Abstract.

Decisive role of pH in synthesis of high purity fluorescent BSA-Au20 nanoclusters

Various types of bovine serum albumin (BSA)-protected fluorescent gold nanoclusters (BSA-AuNCs) have been fabricated and applied in various fields. However, the conventional synthesis methods for BSA-AuNCs usually yield a low photoluminescence quantum yield (PLQY) in solution. In this study, we systematically examined the influences of incubation time, temperature, and pH on the formation process of BSA-AuNCs and then developed a novel strategy to synthesize BSA-AuNCs with PLQY (26%), far exceeding that of existing counterparts. Of the three important factors, pH, temperature, and time, pH plays a key role in the formation of BSA-AuNCs with different compositions and fluorescence properties. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) results showed that BSA-Au₂₀NCs with high purity can be produced at a pH value of 10 and the correct combination of incubation temperature and reaction time. The advantages of the obtained BSA-Au₂₀NCs, including small size, high PLQY, long lifetime, high purity, as well as facile modification, make them ideal candidates for luminescent probes in imaging and sensing applications.

Highly stable folic acid functionalized copper-nanocluster/silica nanoparticles for selective targeting of cancer cells

In this paper, we present a novel strategy to construct folic acid functionalized conjugated Cu nanoclusters (CuNCs) and silica (SiO₂) nanocomposites for targeted detection of cancer cells. First of all, BSA capped CuNCs were encapsulated into a SiO₂ matrix. The resulting CuNCs@SiO₂ nanoparticles showed bright red fluorescence with an enhanced photoluminescence quantum yield compared with free CuNCs, as well as improved stability in a complex biological environment owning to the protection of the SiO₂ matrix. Upon attachment of folic acid via the poly-l-lysine conjugates (PLL-FA) on the surface of CuNCs@SiO₂ driven by electrostatic interaction, the as-prepared CuNCs@SiO₂/PLL-FA nanocomposites are capable of selectively recognizing folate receptor (FR) over-expressed cancer cells rather than FR-negative cells. The cell viability assay proved the low biotoxicity of CuNCs@SiO₂/PLL-FA nanocomposites toward living cells and the in vitro cellular imaging assay results demonstrated their selective endocytosis of FR-positive cells (KB cells), bringing about red fluorescence labeling within the cells. Intriguingly, our strategy provides a novel route to synthesize functional CuNCs@SiO₂/PLL-FA nanocomposites equipped with superior fluorescence properties, high stability against external stimuli and good biocompatibility, and have great application potential in bioimaging imaging and targeted cell detection.

Folic acid functionalized CuNCs@SiO₂ nanocomposites with superior fluorescence properties, high stability and good biocompatibility for targeted cell imaging.

Synthesis and biological evaluation of resveratrol derivatives with anti-breast cancer activity

Resveratrol is a natural phytoestrogen produced by plants to protect themselves from injury, UV irradiation, and fungal attack. The main active structure is E-resveratrol, which has many pharmacological activities. As the structure of resveratrol is similar to the natural estrogen 17β-estradiol and the synthetic estrogen E-diethylstilbestrol, resveratrol is used in reducing the incidence of breast cancer. However, the therapeutic application of resveratrol is limited due to its low bioavailability. To improve its bioavailability and pharmacological activity, some resveratrol derivatives have been designed and synthesized by substitutions of methoxy, hydroxyl, and other functional groups or heterocyclic esterification either on the "A" or "B" ring, and double bonds were replaced by imine bonds and isometric heterocycles such as naphthyl and imidazole, or synthetic resveratrol oligomers. The structures, synthetic routes, and evaluation of the biological activities of these compounds are discussed. These are aimed at providing some references for the study of resveratrol derivatives in anti-breast cancer treatment.

Nanozymes: A New Disease Imaging Strategy

Nanozymes are nanomaterials with intrinsic enzyme-like properties. They can specifically catalyze substrates of natural enzymes under physiological condition with similar catalytic mechanism and kinetics. Compared to natural enzymes, nanozymes exhibit the unique advantages including high catalytic activity, low cost, high stability, easy mass production, and tunable activity. In addition, as a new type of artificial enzymes, nanozymes not only have the enzyme-like catalytic activity, but also exhibit the unique physicochemical properties of nanomaterials, such as photothermal properties, superparamagnetism, and fluorescence, etc. By combining the unique physicochemical properties and enzyme-like catalytic activities, nanozymes have been widely developed for in vitro detection and in vivo disease monitoring and treatment. Here we mainly summarized the applications of nanozymes for disease imaging and detection to explore their potential application in disease diagnosis and precision medicine.

Homogenous Electrochemical Method for Ultrasensitive Detection of Tumor Cells Designed by Introduction of Poly(A) Tails onto Cell Membranes

Rapid and efficient detection of tumor cells is one of the central challenges for modern analytical technology. In this paper, we report a polyadenine (poly(A)) tail-based strategy for ultrasensitive detection of tumor cells in aqueous solution with an electrochemical technique. Specifically, tumor cell-specific EpCAM aptamers without any modification can tightly bind on cell membranes and facilitate the subsequent introduction of multiple poly(A) tails via programmable terminal deoxynucleotidyl transferase (TdT)-mediated elongation. Meanwhile, since tumor cells bearing poly(A) tails can be easily adsorbed onto the surface of gold electrodes through a strong interaction between adenosines and gold, a highly amplified electrochemical signal can be obtained. Thus, by virtue of poly(A) tails, the proposed method allows the detection of as low as 3 cells mL^-1. Compared with the previously reported methods for tumor cells detection, this poly(A)-based homogeneous electrochemical method needs just one enzyme and one aptamer without any modification and avoids the complex and time-consuming modification process of the working electrode, which holds great potential application in the future.

Multi-functional FITC-silica@gold nanoparticles conjugated with guar gum succinate, folic acid and doxorubicin for CT/fluorescence dual imaging and combined chemo/PTT of cancer

A novel type of multi-functional fluorescein isothiocyanate (FITC)-silica (SiO₂)@gold (Au) core-shell nanoparticles covered with folic acid (FA)-conjugated guar gum succinate (GGS) and doxorubicin (DOX) (FITC-SiO₂@Au-DOX-GGS-FA NPs) was prepared for imaging and therapy of cancer. The physicochemical properties of these NPs were analyzed with ¹H NMR, TEM and DLS. The FITC-SiO₂@Au-DOX-GGS-FA NPs exhibited the fluorescence and X-ray attenuation properties due to the presence of FITC-SiO₂@Au hybrid nanostructure. Due to acid-cleavable hydrazone bond between the DOX and NPs, the quantity of DOX delivered from the FITC-SiO₂@Au-DOX-GGS-FA NPs was increased at pH 5.6 than that at pH 7.4. Besides, the multi-functional NPs presented the improved cellular uptake by HeLa cells via FA-receptor-mediated endocytosis due to the existence of FA. The developed NPs also presented the improved cytotoxicity towards the HeLa cells due to its tumor-targetability and DOX/photothermal effect. These results suggested that the FITC-SiO₂@Au-DOX-GGS-FA NPs could be ideal for computed tomography (CT)/fluorescence dual imaging and combined chemo/photothermal therapy (PTT) of cancer.