Fluorescence Imaging For Detection Research Articles

NIR-I Activated Orthogonal NIR-IIb/c Emissions in a Lanthanide-Doped Nanoparticle for Fluorescence Imaging and Information Encryption.

Applying the orthogonal principle for distinguishable second near-infrared (NIR-II) emissions has brought new dimensions for ratio fluorescence imaging (RFI) detection and information encryption, deepening the tissue detection depth and improving signal-to-noise ratio and information security. However, the orthogonal NIR-II emissions underlying these advanced optical applications have been reported only in heterogeneous structures and mixtures, limiting their practicality and potential impact. Herein, NIR-I-activated orthogonal NIR-IIb/c (1530/1825nm) emissions nanoparticles (ONNPs) are developed by spatially separated doping of Tm3+ and Er3+ emitter upon switching 808 and 980nm excitations. RFI techniques and orthogonal NIR-II emission ONNPs are used to demonstrate vessel depth detection based on wavelength-dependent optical attenuation properties in tissue. The superiority of the optical coding and encoding process in a 4×1 binary matrix is demonstrated for anticounterfeiting and decryption imaging of quick-response (QR) code for information storage. The research progress of this NIR-II orthogonal emissions probe will drive the development of biomedical sensing, imaging safety, and future biophotonics technologies.

Artificial Compound Eye with Tunable Properties for Enhancement in Fluorescence Imaging and Raman Detection

AbstractArtificial compound eye (CE) draws inspiration from nature, offering advanced imaging capabilities and an expansive field of view. In this work, an innovative technique is developed for the creation of CE with tunable dimensions. A solution‐based process is employed that involves in situ polymerization of surface nanodroplets prior to soft lithography to produce CE consisting of millions of ommatidia. The fabricated CE comprised of a densely arranged array of microwells, each with a base radius of 5 µm. Situated on a millimeter‐sized spherical dome, the CE can be tailored to arbitrary dimensions, enhancing its adaptability with a wide angular field of view up to 118°. The CE is used to enhance signal detection in fluorescent compounds, reaching a detection limit of 107 times lower concentration than that without using CEs in bulk solution. The signal enhancement capabilities are further utilized for surface‐enhanced Raman spectroscopy by using a portable handheld device, with an enhancement factor of 2. The fabrication technique underscores the advantages of the approach in simplicity, reproducibility, and efficiency in creating CE. The potential applications of CE may be extended to various domains, such as optical sensing, light‐dependent signal enhancement, motion perception, and medical endoscopy.

"Turn-on" and pinhole-free ultrathin core-shell Au@SiO2 nanoparticle-based metal-enhanced fluorescent (MEF) chemodosimeter for Hg2.

This study reports a metal-enhanced fluorescence chemodosimeter for highly sensitive detection of Hg2+ ions. Silica-coated Au nanoparticles (Au@SiO2 NPs) with a pinhole-free 4-5 nm shell were synthesized and functionalized with a monolayer of turn-on fluorescent probes. Compared to other organic fluorescent probes suffering from poor biocompatibility and detection limits, this design of a monolayer of turn-on fluorescent probes immobilized on the Au@SiO2 NPs with a pinhole-free 4-5 nm shell avoids fluorescence quenching and allows the fluorescent probe within the field of the inner Au NPs to experience metal-enhanced fluorescence. With this design, the chemodosimeter permits fluorescence emission in the presence of Hg2+ ions, because they trigger the ring-opening reaction of the fluorescent probe immobilized on the Au@SiO2 NPs. Additionally, the fluorescent probe is distanced by the thin SiO2 shell from directly attaching to the metallic Au NPs, which not only avoids fluorescence quenching but allows the fluorescent probe within the long-ranged field of the inner Au NPs to experience metal-enhanced fluorescence. As a result, the detection limit for the chemodosimeter can reach up to 5.0 × 10-11 M, nearly two orders of magnitude higher than that achieved for the free fluorescent probe. We also demonstrate the acquisition of images of Hg2+ in HTC116 cells and zebrafish using a simple fluorescence confocal imaging technique. The fluorescence response results for HTC116 cells and zebrafish show that the probes can permeate into cells and organisms. Considering the availability of the many organic fluorescent probes that have been designed, the current designed metal-enhanced fluorescence chemodosimeter holds great potential for fluorescence detection of diverse species and fluorescence imaging.

Nanotechnology boosts the efficiency of tumor diagnosis and therapy.

The incidence and mortality of cancer are gradually increasing. The highly invasive and metastasis of tumor cells increase the difficulty of diagnosis and treatment, so people pay more and more attention to the diagnosis and treatment of cancer. Conventional treatment methods, including surgery, radiotherapy and chemotherapy, are difficult to eliminate tumor cells completely. And the emergence of nanotechnology has boosted the efficiency of tumor diagnosis and therapy. Herein, the research progress of nanotechnology used for tumor diagnosis and treatment is reviewed, and the emerging detection technology and the application of nanodrugs in clinic are summarized and prospected. The first part refers to the application of different nanomaterials for imaging in vivo and detection in vitro, which includes magnetic resonance imaging, fluorescence imaging, photoacoustic imaging and biomarker detection. The distinctive physical and chemical advantages of nanomaterials can improve the detection sensitivity and accuracy to achieve tumor detection in early stage. The second part is about the nanodrug used in clinic for tumor treatment. Nanomaterials have been widely used as drug carriers, including the albumin paclitaxel, liposome drugs, mRNA-LNP, protein nanocages, micelles, membrane nanocomplexes, microspheres et al., which could improve the drug accumulate in tumor tissue through enhanced permeability and retention effect to kill tumor cells with high efficiency. But there are still some challenges to revolutionize traditional tumor diagnosis and anti-drug resistance based on nanotechnology.

A novel fluorescent probe based on naphthimide for H2S identification and application

In view of the superior chemical activity of selenoether bond (–Se–) and the excellent optical properties of naphthimide, a novel fluorescent probe (NapSe) with near-rectangular structure, which contains double naphthimide fluorophores linked by selenoether bond, is designed for specific fluorescence detection of hydrogen sulfide (H2S). NapSe has excellent optical properties: super large Stokes Shift (190 nm) and good stability in a wide pH range. The selectivity of NapSe fluorescence detection of H2S is high, and displays excellent "turn-on" phenomenon and strong anti-interference. And the fluorescence intensity increased obviously, reaching 42 times. The time response of probe NapSe is very rapid (3 min) compared with other fluorescence probes that respond to H2S. It shows high sensitivity by calculating the detection limit (LOD) as low as 5.4 μM. Notably, the identification of H2S by probe NapSe has been successfully applied to the detection of test paper and the detection of exogenous and endogenous fluorescence imaging of MCF-7 breast cancer cells.

Strategy of eudragit coated curcumin nanoparticles delivery system: Release and cell imaging studies in simulated gastrointestinal microenvironments

Curcumin has a broad-spectrum anti-tumor effect and has no toxic side effects. However, the unique diketone structure of curcumin will undergo diketo-enol tautomerism under different acid-base conditions, resulting in its instability under physiological conditions. In addition, the low biocompatibility and absorption rate of curcumin also limit the use of curcumin drugs. In this paper, curcumin was modified by substitution of acryloyl and acrylsulfonyl groups, and four kinds of nanoparticles with regular morphology were prepared using non-toxic and non-irritating acrylic resin as coating material to improve the stability and bioavailability of the compounds. Zeta potential testing shows that the composites surface carries positive charges and have good stability. In the release experiment, four complexes have the potential for slow and controlled release. Imaging of Hela cells with different channels was performed, and the imaging results showed that the complexes could enter the cells and be absorbed by them, demonstrating good imaging performance. MTT experiments have shown that the complexes have certain anti-tumor activity and low cytotoxicity. In general, the complexes synthesized in this paper have potential in the field of drug fluorescence imaging detection. At the same time, this experiment provides a new idea for the design of slow and controlled release of drugs.

Peptide nanodots-bridged metal-organic framework (PNMOF): Intelligently design a cascade amplification platform for smartphone-facilitated mobile fluorescence imaging detection of pyrethroids

Within this study, a peptide nanodots-bridged metal–organic framework (PNMOF) has been constructed by predictably assembling highly efficient fluorescent dipeptide nanodots into the three-dimensional framework upon coordination of Zn(II) and dihydroxamate linkers. The established system was on behalf of a new class of tripartite hybrid material, i.e., metal ion, organic linker, and peptide nanodot, which integrated the chemical and structural versatility in a modular fashion. Owing to its unique open framework with tripartite construction, PNMOF exhibited a rapid and sensitive response, therefore, the target (e.g., lambda-cyhalothrin, LCY) driven into the tripartite hybrid structure stimulated a cascade amplification effect. LCY can cause significant fluorescence quenching in the PNMOF-based cascade amplification platform due to the charge transfer mechanism, which was confirmed by density functional theory calculations. PNMOF-based cascade amplification platform was employed for fluorescence imaging detection of pyrethroids in solution and solid state assisted by the smartphone. The limit of detection was as low as 0.34 μg/L and the recoveries percentage in real agricultural products was calculated as 88.26–108.17%. This work not only underlies the structural diversity of conventional metal–organic framework but also offers a useful tool in environmental protection and food safety.

Noninvasive Early Diagnosis of Allograft Rejection by a Granzyme B Protease Responsive NIR-II Bioimaging Nanosensor.

Early diagnosis of allograft rejection helps to improve the immune-related management of transplant recipients. The clinically-used core needle biopsy method is invasive and subject to sampling error. In vivo fluorescence imaging for monitoring immune-related processes has the advantages of non-invasiveness, fast feedback and high sensitivity. Herein, we report a responsive second near-infrared (NIR-II) fluorescent nanosensor (ErGZ) to detect early allograft rejection. ErGZ allows ratiometric in vivo fluorescence sensing of granzyme B, which is overexpressed in recipients' T cells during the onset of rejection. The sensor demonstrates efficacious detection of allograft rejection with high sensitivity and specificity, which accomplishes non-invasive diagnosis of rejection in skin and deep buried islets transplant mice models 2 d and 5 d earlier than biopsy, by in vivo fluorescence imaging and urinary detection, respectively, providing a valuable approach for therapeutical management.

Noninvasive Early Diagnosis of Allograft Rejection by a Granzyme B Protease Responsive NIR‐II Bioimaging Nanosensor

AbstractEarly diagnosis of allograft rejection helps to improve the immune‐related management of transplant recipients. The clinically‐used core needle biopsy method is invasive and subject to sampling error. In vivo fluorescence imaging for monitoring immune‐related processes has the advantages of non‐invasiveness, fast feedback and high sensitivity. Herein, we report a responsive second near‐infrared (NIR‐II) fluorescent nanosensor (ErGZ) to detect early allograft rejection. ErGZ allows ratiometric in vivo fluorescence sensing of granzyme B, which is overexpressed in recipients’ T cells during the onset of rejection. The sensor demonstrates efficacious detection of allograft rejection with high sensitivity and specificity, which accomplishes non‐invasive diagnosis of rejection in skin and deep buried islets transplant mice models 2 d and 5 d earlier than biopsy, by in vivo fluorescence imaging and urinary detection, respectively, providing a valuable approach for therapeutical management.

Abstract 2385: Targeting mannose receptor expression on macrophages for sentinel lymph node mapping in endometrial cancer: murine model

Abstract Background: Sentinel lymph node (SLN) mapping has been used in various cancer surgery including endometrial cancer as a targeted assessment tool for identifying lymph node metastases, an alternative for complete lymphadenectomy to minimize surgical morbidity. Neomannosyl human serum albumin (MSA) targets the macrophage mannose receptor CD206 which is highly expressed in metastatic lymph node. The aim of this study was to evaluate the effectiveness of indocyanine green-neomannosyl human serum albumin (MSA:ICG) which targets macrophage mannose receptor CD206 for SLN mapping. Methods: LN targeting ability was examined on mouse footpad models of uterine cancer using MSA:ICG and ICG for comparison. Seven mice with uterine cancer and 2 mice without cancer as a control group were each assigned to MSA:ICG and ICG groups. After injection of tracers, fluorescence images were taken and SLN biopsy was done to confirm LN metastasis status. We compared the signal-to-background ratio (SBR) according to time. Results: In both MSA:ICG and ICG group, 16 lymph nodes out of 18 were detected using fluorescence imaging (detection rate: 88.9%). Four lymph nodes in MSA:ICG group and 5 lymph nodes in ICG group were metastatic among 16 lymph node each group. Excluding lymph nodes that were not detected, the SBR after the injection of MSA:ICG group was significantly higher than ICG group in metastatic LN (MSA:ICG 4.36 vs ICG 3.07, p<0.001), non-metastatic lymph nodes (MSA:ICG 3.11 vs ICG 1.93, p=0.001), and normal control lymph nodes (MSA:ICG 1.38 vs ICG 0.54, p<0.001). Comparing signal intensity according to CD206 expression, there was no difference in SBR values between the two groups in patients without CD206 expression, but the MSA group had a statistically significantly higher SBR value than the ICG group (p<0.001) in patients with CD206 moderate or high expression. Conclusions: This study showed that MSA:ICG may be an effective tracer for sentinel lymph node mapping. In addition, the metastatic lymph nodes expressing CD206 showed higher signal than normal lymph nodes in MSA:ICG group, unlike in ICG group. Further studies using larger animal models and clinical trials are needed to confirm this result. Citation Format: Hyun-Woong Cho, OK Hwa Jeon, Sanghoon Lee, Hyun Koo Kim, Jae Kwan Lee, Jin Hwa Hong. Targeting mannose receptor expression on macrophages for sentinel lymph node mapping in endometrial cancer: murine model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2385.

An ICT-PET dual-controlled strategy for improving molecular probe sensitivity: Application to photoactivatable fluorescence imaging and H2S detection

The organic small molecule fluorescent probes are very effective tool for accurately analyzing target molecules and super-resolution microscopy biological imaging. Generally, reducing the interference of background fluorescence is one of the effective strategies to improve the resolution and signal-to-noise ratio of biological imaging. Herein, in this work, using the synergistic effect of the ICT-PET dual quenching mechanism to reduce background fluorescence, the fluorescent probe Np-N3 with naphthalimide and small size azide as photocage and the recognition site of H2S was designed and synthesized. The synergistic mechanism of ICT-PET was computationally demonstrated by TD-DFT. The Np-N3 showed low background fluorescence, high sensitivity and high selectivity for visible light and H2S, respectively. Meanwhile, under visible light irradiation (465 nm), the azide was easily reduced to amino in situ without complicated separation steps, restoring strong emission in a short time (<3 min). Importantly, the spatiotemporal-controlled imaging of live HeLa cells was successfully achieved. In addition, the probe was also applied to detect and image H2S in solution and living HeLa cells.

An ultrasensitive GSH-specific fluorescent probe unveils celastrol-induced ccRCC ferroptosis

Glutathione (GSH) is closely related to the occurrence and development of tumors. The intracellular GSH levels are abnormally altered when tumor cells undergo programmed cell death. Therefore, real-time monitoring of the dynamic changes of intracellular GSH levels can better enable the early diagnosis of diseases and evaluate the effects of cell death-inducing drugs. In this study, a stable and highly selective fluorescent probe AR has been designed and synthesized for the fluorescence imaging and rapid detection of GSH in vitro and in vivo, as well as patient-derived tumor tissue. More importantly, the AR probe can be used to track changes in GSH levels and fluorescence imaging during the treatment of clear cell renal cell carcinoma (ccRCC) with celastrol (CeT) via inducing ferroptosis. These findings demonstrate that the developed fluorescent probe AR exhibits high selectivity and sensitivity, as well as good biocompatibility and long-term stability, which can be used to image endogenous GSH in living tumors and cells. Also, a significant decrease in GSH levels was observed by the fluorescent probe AR during the treatment of ccRCC with CeT-induced ferroptosis in vitro and in vivo. Overall, these findings will provide a novel strategy for celastrol targeting ferroptosis in the treatment of ccRCC and the application of fluorescent probes to help reveal the underlying mechanism of CeT in the treatment of ccRCC.

Development of an Au nanoclusters based activatable nanoprobe for NIR-II fluorescence imaging of gastric acid

Gastric acid is an important functional substance secreted by the stomach of the living organisms, reflecting the gastric physiological condition. The sensing of gastric acid in vivo is of great significance for evaluation of gastric function, diagnosis and treatment of gastric diseases and maintenance of organism health but remains challenging due to the harsh acid and digestive environment of stomach. This study developed an activatable nanoprobe based on Au nanoclusters (Au NCs) for sensitive and real-time noninvasive near-infrared II (NIR-II) fluorescence imaging detection of gastric acid in vivo for the first time. The Au NCs were encapsulated by polydopamine to have enhanced NIR-II luminescence and high stability and combined with methylene blue to possess the pH responsiveness for gastric acid imaging. The developed nanoprobe could not only monitor gastric acid secretion in vivo but also imaging the changes of gastric acid caused by feeding, acid-inhibition drugs and gastric ulcer disease. This study provides a promising avenue for the improvement of the application performance of Au NCs and imaging analysis of gastric acid and related gastric diseases.

Comprehensive quantitative analysis of erythrocytes and leukocytes using trace volume of human blood using microfluidic-image cytometry and machine learning.

A diagnostic test based on microfluidic image cytometry and machine learning has been designed and applied for accurate classification of erythrocytes and leukocytes, including a unique fully-automated 5-part quantitative differentiation into neutrophils, lymphocytes, monocytes, eosinophils, and basophils, using minute amounts of whole blood in a single counting chamber. A low-cost disposable multilayer microdevice for microfluidic image cytometry was developed that comprises a 1 mm × 22 mm × 70 μm (w × l × h) rectangular microchannel, allowing the analysis of trace volume of blood (20 μL) for each assay. Automated analysis of digitized binary images applying a border following algorithm was performed allowing the qualitative analysis of erythrocytes. Bright-field imaging was used for the detection of erythrocytes and fluorescence imaging for 5-part differentiation of leukocytes after acridine orange staining, applying a convolutional neural network enabling unparalleled speed for identification and automated morphology classification yielding 98.57% accuracy. Blood samples were obtained from 30 volunteers and count values did not significantly differ from data obtained using a commercial automated hematology analyzer.

Establishment of a platform imaged capillary isoelectric focusing (icIEF) characterization method for adeno-associated virus (AAV) capsid proteins

Herein we describe a platform method to study the charge heterogeneity of adeno-associated virus (AAV) capsid proteins. The method, based on imaged capillary isoelectric focusing (icIEF) with native fluorescence imaging detection, was validated, and can be used as an identity assay and stability indication assay. The protocol was also evaluated following the White Analytical Chemistry principle, its score is 89.7. The method is shown to be platform, with eight different AAV serotypes successfully analyzed. The resulting AAV serotype ‘fingerprints’ can be used for AAV identity and stability indication. • It is a platform method to study the charge heterogeneity of adeno-associated virus (AAV) capsid proteins. The method, based on imaged capillary isoelectric focusing (icIEF) with native fluorescence imaging detection, was validated, and evaluated as an identity assay and stability indication assay for AAVs of different serotypes. The score of the protocol is well balanced in the White Analytical Chemistry principle is 89.7. The method is shown to be platform, with eight different AAV serotypes successfully analyzed. The resulting AAV serotype ‘fingerprints’ (electropherograms) can be used for AAV identity and stability indicator

Target-triggered Au NPs self-assembled for fluorescence-SERS dual-mode monitoring of telomerase in living cells and in vivo

Telomerase was regarded as a pivotal tumor marker for cancers diagnosis and prognosis evaluation. Hence, the accurate quantification detection and distribution information of telomerase in complex biological environment is undoubtedly very important. Herein, we developed a dual-mode strategy for telomerase detection which combined the advantages of both surface-enhanced Raman scattering (SERS) and fluorescence approaches. The nanoprobes, consists of Au NPs and specific nucleic acid probes, would be triggered by telomerase to generate electromagnetic hot spots enhanced Au dimers for telomerase fluorescence imaging and label-free Raman detection after entering the living cells. In addition, a stronger fluorescent signal was generated after two signal amplifications. With the help of ATP and catalytic hairpin assembly (CHA), more Au dimers will be generated to increase the Raman signal. The experimental results showed that the dual-mode nanoprobe has great selectivity and sensitivity to telomerase and could distinguish different kinds of tumor cells by in situ imaging. Limit of detection (LOD) was 7.76 HeLa cells for fluorescence detection and 2.98 Hela cells fore SERS detection. This nanoplatform would be a promising dual-mode diagnostic strategy for biomarkers in complex biological environment.

Nonenzymatic Autonomous Assembly of Cross-Linked Network Structures from Only Two Palindromic DNA Components for Intracellular Fluorescence Imaging of miRNAs.

The abnormal expression of miRNA-21 is often found in tumor specimens and cell lines, and thus, its specific detection is an urgent need for the diagnosis and effective therapy of cancers. In this contribution, we demonstrate a palindrome-based hybridization chain reaction (PHCR) upon the stimuli of a short oligonucleotide trigger to perform the autonomous assembly of cross-linked network structures (CNSs) for the amplification detection of miRNA-21 and sensitive fluorescence imaging of cancerous cells. The building blocks are only two palindromic hairpin-type DNA strands that are separately modified with different fluorophores (Cy3 and Cy5), which is easily combined with the catalytic hairpin assembly (CHA) technique that can further amplify the signal output. Utilizing the CHA-PHCR assay system, a small amount of miRNA-21 can activate many triggers via CHA and in turn induce the PHCR-based CNS assembly from more DNA building blocks, bringing Cy3 and Cy5 into close proximity to each other and generating ultrasensitive fluorescence resonance energy transfer signals. As a result, target miRNA can be quantitatively detected down to as low as 10 pM with high assay specificity. The coexisting nontarget miRNAs and other biomacromolecules do not interfere with signal transduction. The developed assay system is suitable for screening different expression levels of miRNA-21 in living cells by fluorescence imaging. The palindrome-based cross-linking assembly can enhance the intracellular stability of assembled nanostructures by at least fivefold and exhibit the good universality for the detection of other miRNAs. Moreover, cancerous cells can be distinguished from healthy cells, and the CHA-PHCR assay is in good accordance with the gold standard PCR method, indicating a promising platform for the diagnosis of human cancers and other genetic diseases.

In situ immobilization of silver nanocrystals in carbon nanoparticles for intracellular fluorescence imaging and hydroxyl radicals detection

Silver nanoparticles (Ag NPs) have attracted extensive research interest in bioimaging and biosensing due to their unique surface plasmon resonance. However, the potential aggregation and security anxiety of Ag NPs hinder their further application in biomedical field due to their high surface energy and the possible ionization. Here, binary heterogeneous nanocomplexes constructed from silver nanoparticles and carbon nanomaterials (termed as C-Ag NPs) were reported. The C-Ag NPs with multiple yolk structure were synthesized via a one-step solvothermal route using toluene as carbon precursor and dispersant. The hydrophilic functional groups on the carbon layer endowed the C-Ag NPs excellent chemical stability and water-dispersity. Results showed that C-Ag NPs demonstrated excellent safety profile and excellent biocompatibility, which could be used as an intracellular imaging agent. Moreover, the C-Ag NPs responded specifically to hydroxyl radicals and were expected to serve as a flexible sensor to efficiently detect diseases related to the expression of hydroxyl radicals in the future.

Amorphous B-doped graphitic carbon nitride quantum dots with high photoluminescence quantum yield of near 90% and their sensitive detection of Fe2+/Cd2+

Graphitic carbon nitride quantum dots (CNQDs) are emerging as attractive photoluminescent (PL) materials with excellent application potential in fluorescence imaging and heavy-metal ion detection. However, three limitations, namely, low quantum yields (QYs), self-quenching, and excitation-dependent PL emission behaviors, severely impede the commercial applications of crystalline CNQDs. Here we address these three challenges by synthesizing boron-doped amorphous CNQDs via a hydrothermal process followed by the top-down cutting approach. Structural disorder endows the amorphous boron-doped CNQDs (B-CNQDs) with superior elastic strain performance over a wide range of pH values, thus effectively promoting mass transport and reducing exciton quenching. Boron as a dopant could fine-tune the electronic structure and emission properties of the PL material to achieve excitation-independent emission via the formation of uniform boron states. As a result, the amorphous B-CNQDs show unprecedented fluorescent stability (i.e., no obvious fading after two years) and a high QY of 87.4%; these values indicate that the quantum dots obtained are very promising fluorescent materials. Moreover, the B-CNQDs show bright-blue fluorescence under ultraviolet excitation when applied as ink on commercially available paper and are capable of the selective and sensitive detection of Fe2+ and Cd2+ in the parts-per-billion range. This work presents a novel avenue and scientific insights on amorphous carbon-based fluorescent materials for photoelectrical devices and sensors.

A One-Two-Three Multifunctional System for Enhanced Imaging and Detection of Intracellular MicroRNA and Chemogene Therapy.

Simultaneous imaging, diagnosis, and therapy can offer an effective strategy for cancer treatment. However, the complex probe design, poor drug release efficiency, and multidrug resistance remain tremendous challenges to cancer treatment. Here, a novel one-two-three system is built for enhanced imaging and detection of miRNA-21 (miR-21) overexpressed in cancer cell and chemogene therapy. The system consists of dual-mode DNA robot nanoprobes assembled by two types of hairpin DNAs and three-way branch DNAs modified on gold nanoparticles, with intercalating anticancer drugs (doxorubicin), into DNA duplex GC base pairs. In the system, via intracellular ATP-accelerated cyclic reaction triggered by miR-21, fluorescence and SERS signals were alternated with DNA structure switch, and the precise SERS detection of miRNA and fluorescence imaging oriented "on-demand" release of two types of anticancer drugs (anti-miR-21 and Dox) are achieved. Thus, "one-two-three" means one kind of miR-21-triggered endogenous substance accelerated cyclic reaction, two modes of signal switch, and three functions including enhanced imaging, detection, and comprehensive treatment. The one-two-three system has some notable merits. First, ATP as an endogenous substance promotes DNA structure switching and accelerates the cyclic reaction. Second, the treatment with a dual-mode signal switch is more reliable and accurate and can provide more abundant information than a single-mode treatment platform. Thus, the imaging and detection of intracellular miRNA and effective comprehensive therapy are realized. In vivo results indicate that the system can provide new insights and strategies for diagnosis and therapy.