ABSTRACT
Radiotherapy still fails to achieve satisfactory efficacy in the treatment of malignant tumors, and applying radiotherapy sensitizers is an effective method to improve the efficacy of radiotherapy. Gold nanomaterials can effectively increase the sensitivity of tumor cells to radiotherapy due to their high atomic numbers. Gold nanoclusters have more excellent radiobiological and radiophysical properties due to their smaller size. This paper reviews the special radiobiological and radiophysical properties of gold nanoclusters and describes in detail their sensitizing effects in external radiation radiotherapy, radionuclide therapy, and X-ray induced photodynamic therapy.
ABSTRACT
【Objective】 To establish a simple, economical and rapid method for the determination of methylene blue (MB) release in virus inactivation bag. 【Methods】 Based on the fluorescence energy transfer between MB and BSA-stabilized gold nanoclusters (BSA-AuNCs), the standard curve of MB determination was established by measuring the fluorescence quenching degree of MB to BSA-AuNCs in different concentrations to conduct the determination of MB release in virus inactivation bag. 【Results】 There was a good linear relationship between the MB concentration (cMB) and the fluorescence quenching degree of BSA-AuNCs[ (I0-I)/I0=0.018cMB+ 0.021(r=0.996)] when the fluorescence emission wavelength was about 620 nm and the cMB was in the range of (0.9-36) μmoL/L. The recovery of MB was 98.00% -101.95 % when applied to determine MB at high, medium, and low concentrations, the obtained intra-day variation coefficients were 0.73%, 0.81% and 0.77% respectively, and the obtained inter-day variation coefficients were 3.92%, 3.81%, and 4.73% respectively. There was no significant difference between the results measured by this method and those measured by combination of solid-phase extraction and spectrophotometry(P>0.05). 【Conclusion】 The fluorescence energy transfer method could achieve simple and rapid determination of MB release in virus inactivation bag with accurate and reliable results.
ABSTRACT
Therapeutic nanoparticles are designed to enhance efficacy, real-time monitoring, targeting accuracy, biocompatibility, biodegradability, safety, and the synergy of diagnosis and treatment of diseases by leveraging the unique physicochemical and biological properties of well-developed bio-nanomaterials. Recently, bio-inspired metal nanoclusters (NCs) consisting of several to roughly dozens of atoms (<2 nm) have attracted increasing research interest, owing to their ultrafine size, tunable fluorescent capability, good biocompatibility, variable metallic composition, and extensive surface bio-functionalization. Hybrid core-shell nanostructures that effectively incorporate unique fluorescent inorganic moieties with various biomolecules, such as proteins (enzymes, antigens, and antibodies), DNA, and specific cells, create fluorescently visualized molecular nanoparticle. The resultant nanoparticles possess combinatorial properties and synergistic efficacy, such as simplicity, active bio-responsiveness, improved applicability, and low cost, for combination therapy, such as accurate targeting, bioimaging, and enhanced therapeutic and biocatalytic effects. In contrast to larger nanoparticles, bio-inspired metal NCs allow rapid renal clearance and better pharmacokinetics in biological systems. Notably, advances in nanoscience, interfacial chemistry, and biotechnologies have further spurred researchers to explore bio-inspired metal NCs for therapeutic purposes. The current review presents a comprehensive and timely overview of various metal NCs for various therapeutic applications, with a special emphasis on the design rationale behind the use of biomolecules/cells as the main scaffolds. In the different hybrid platform, we summarize the current challenges and emerging perspectives, which are expected to offer in-depth insight into the rational design of bio-inspired metal NCs for personalized treatment and clinical translation.
ABSTRACT
Cyclodextrin metal-organic framework (CD-MOF) as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol (STV). The solubility of STV was lower than 20.00 ng/mL at pH 1.0 and pH 4.5, whilst its solubility increased to 20,074.30 ng/mL at pH 6.8 and 129.58 ng/mL in water with a significant pH-dependence. The
ABSTRACT
One-step green synthetic approach,with bovine serum albumin(BSA) as stabilizer and reductant, was developed for preparation of BSA hybrid fluorescence gold nanoclusters (AuNCs@BSA). The prepared AuNCs@BSA exhibited strong red fluorescence under UV light illumination. Upon excited at 360 nm, the fluorescence spectrum of AuNCs@ BSA exhibited maximum emission peak at 635 nm. AuNCs@ BSA was presented as uniform spherical morphology with diameter at (2.0 ±0.05) nm. The fluorescence of AuNCs@BSA could be quenched by Hg2+because of its metallophilic reaction. Based on the fluorescent spectrometry, a rapid detection system was developed for Hg2+detection in tap water. The AuNCs@BSA amount, pH and buffer system were optimized in this study. According to optimization results, ultrapure water (pH 5.0) was selected to dilute the AuNCs@BSA by 100 times, and 50 μL/well of AuNCs@BSA dilution was applied to detect mercury ion in tap water. Under the optimized conditions, the detection could be completed within 3 min,the fluorescence intensity of the system was linearly proportional to the concentration of mercury ion in the range of 0.5–900 μg/L with linear equations y=-26.76lgx+803.1(0.5-75 μg/L,R2=0.9951) and y=-0.27x+762.02 (75-900 μg/L,R2=0.9959). The limit of detection was 0.14 μg/L(3σ). The average recoveries in spiked tape water samples ranged from 86.8%-113.4% with relative standard deviation of less than 15%. The result implied that the developed method was able to apply to detect mercury ion rapidly, sensitively and conveniently.
ABSTRACT
A colorimetric method was developed for detection of mercury based on the inhibition of oxidation of peroxidase substrates. The as-prepared gold nanoclusters ( Au NCs), which has been stabilized and reduced by Glutathione (GSH), can effectively catalyze the H2 O2-TMB to generate a blue color signal. It is interestingly that Hg2+ can inhibit the oxidation of peroxidase substrates, thus causing a color diminished. Taking advantage of the inhibitive effect of Hg2+, a novel Hg2+ sensor has been developed. In this system, sensing conditions, including pH of the buffer solution, substrate concentration and time, were optimized. Under the optimal conditions, the probe showed a linear range of 10 - 300 nmol/ L ( R2 = 0. 997) with a detection limit of 6. 26 nmol/ L. In addition, this sensor exhibited good selectivity and sensitivity for Hg2+against other common environmental mental ions, providing a new method for water analysis.
ABSTRACT
A terminal deoxynucleotidyl transferase ( TdT ) amplification based DNA-copper nanoclusters (CuNCs) sensor was developed for detection of L-histidine ( L-His). Single strand DNA containing poly-thymine ( T) sequences were synthesized by TdT in the presence of dTTP. In blank control, poly-T sequences worked as templates of CuNCs due to the affinity between thymine and copper ions( II) . Fluorescence intensity was enhanced when CuNCs formed with reducing agents. In the presence of L-His, the imidazolyl group of L-His worked as a chelating agent that formed L-His-Cu2+ chelated complex. Thus less copper ions were induced in poly-T sequences, and less CuNCs were obtained to produce week fluorescence signals. A good linear correlation was obtained between fluorescence change and the logarithm of the L-His concentration over the range of 5. 0 ×10-9-5. 0 ×10-4 mol/L. The detection limit was estimated as 3. 4 ×10-9 mol/L. And the recoveries were 97. 4%-104. 6% for the actual urine samples. Compared with other methods of synthetic CuNCs, this method allowed to specifically determining L-histidine without template or labeling, which showed good potential in biomedical and clinical analysis.
ABSTRACT
MicroRNAs (miRNAs) are essential small RNA molecules (20–24 nt) that negatively regulate the expression of target genes at the post-transcriptional level. Due to their roles in a variety of biological processes, the aberrant expression profiles of miRNAs have been identified as biomarkers for many diseases, such as cancer, diabetes, cardiovascular disease and neurodegenerative diseases. In order to precisely, rapidly and economically monitor the expression of miRNAs, many cutting-edge nanotechnologies have been developed. One of the nanotechnologies, based on DNA encapsulated silver nanoclusters (DNA/AgNCs), has increasingly been adopted to create nanoscale bio-sensing systems due to its attractive optical properties, such as brightness, tuneable emission wavelengths and photostability. Using the DNA/AgNCs sensor methods, the presence of miRNAs can be detected simply by monitoring the fluorescence alteration of DNA/AgNCs sensors. We introduce these DNA/ AgNCs sensor methods and discuss their possible applications for detecting miRNA biomarkers in neurodegenerative diseases.
Subject(s)
Biological Phenomena , Biomarkers , Cardiovascular Diseases , DNA , Fluorescence , MicroRNAs , Nanotechnology , Neurodegenerative Diseases , RNA , SilverABSTRACT
A terminal deoxynucleotidyl transferase ( TdT ) amplification based DNA-copper nanoclusters (CuNCs) sensor was developed for detection of L-histidine ( L-His). Single strand DNA containing poly-thymine ( T) sequences were synthesized by TdT in the presence of dTTP. In blank control, poly-T sequences worked as templates of CuNCs due to the affinity between thymine and copper ions( II) . Fluorescence intensity was enhanced when CuNCs formed with reducing agents. In the presence of L-His, the imidazolyl group of L-His worked as a chelating agent that formed L-His-Cu2+ chelated complex. Thus less copper ions were induced in poly-T sequences, and less CuNCs were obtained to produce week fluorescence signals. A good linear correlation was obtained between fluorescence change and the logarithm of the L-His concentration over the range of 5. 0 ×10-9-5. 0 ×10-4 mol/L. The detection limit was estimated as 3. 4 ×10-9 mol/L. And the recoveries were 97. 4%-104. 6% for the actual urine samples. Compared with other methods of synthetic CuNCs, this method allowed to specifically determining L-histidine without template or labeling, which showed good potential in biomedical and clinical analysis.
ABSTRACT
A sensitive colorimetric method for the detection of copper ions (Cu2+) was developed based on the surface modification of silver/platinum nanoclusters (Ag/Pt NCs) and regulation of peroxidase-like activity. It was found that 3-mercaptopropionic acid (MPA) could inhibit the catalytic ability of Ag/Pt NCs; however, it lost the inhibition toward catalytic ability of Ag/Pt NCs after oxidized by oxygen through the catalysis of Cu2+. On the basis of this, a colorimetric method was developed for the detection of Cu2+ through measuring the colorimetric signal variation of the TMB-H2O2 reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions. The linear range was 10-100 nmol/L and the detection limit was 5.0 nmol/L (3σ). The above method was also applied to detect real water samples and spiked samples, and the results demonstrated that this method was simple with low cost.
ABSTRACT
Based on melamine-Cu conjugate and subsequent interruption of formation of polythymine (Poly T)-templated copper nanoclusters (CuNCs), a novel fluorescent strategy was developed for detection of melamine.The method relied on the principle that the coordination of melamine to copper would be unfavorable for the reduction of Cu2+ in the poly T-CuNCs synthesis process, and thereby resulting in the decrease of fluorescence intensity of CuNCs.By this method, the fluorescence response of CuNCs displayed an linear relationship with melamine concentration in the range from 5 μmol/L to 120 μmol/L.The detection limit was 1.5 μmol/L.Furthermore, the assay was successfully applied in the detection of melamine in milk samples with good recoveries.
ABSTRACT
A new type of fluorescent gold nanoclusters (MU-Au NCs) was prepared by hydrothermal synthesis method using ammonium benzoate murexide (MU) as reducing agent and protecting agent.The synthesis method was simple and rapid.Based on the fluorescence quenching ability of spermine, a turn off type fluorescence analysis method was established for rapid and ultra sensitive detection of spermine.The linear range for detection of spermine was 0.003-300 μmol/L and the detection limit was 1 nmol/L (S/N=3).The established analytical method of spermine provided theoretical basis and reference for construction of spermine biosensor and actual sample detection.
ABSTRACT
In the past ten years, the development of electrochemiluminescent ( ECL ) analytical methods based on various types of nanostructures has become a research hotspot. Nanocluster, an intermediate between molecules and conventional nanoparticles, is renowned for its luminescent feature. The first report on ECL for nanoclusters can be traced back to 2009 . Here we summarized the main research progresses since 2011 . Firstly, the preparation of ECL-related nanoclusters was briefly introduced. Then, the mechanisms and applications of ECL by nanoclusters were described. To improve ECL performances, two main strategies, i. e. , nanostructure-based ECL enhancement and biological signal amplification were proposed. Besides, the nanoclusters as the energy transfer receptors in ECL systems were also discussed. In prospect part, the future development of ECL by nanoclusters was considered. We believed that the synthesis of high quality nanoclusters, the reveal of ECL structure-activity relationships, the rationale design and application of near-infrared ECL, and the role of ECL in the interdisciplinary research were the main problems we faced in the future.
ABSTRACT
There is high demand for a sensitive method for miRNA detection in clinical diagnosis. In this work, we developed a method for miRNA detection based on the surface plasmon-enhanced energy transfer ( SPEET ) between gold nanoparticles ( AuNPs ) and silver nanoclusters ( AgNCs ) , coupled with DNA polymerase and nicking enzyme-assisted isothermal amplification for target recycling. Two DNA probes ( Probe a and Probe b) were assembled onto the surface of AuNPs to form Probe b-Probe a-AuNP conjugates. Probe a consisted three domains:the complementary sequence of miRNA, the specific site of the nicking enzyme, and the self-assembly sequence for AgNCs. The 3′ end of Probe a was modified with thiol as a binding site for AuNPs. The SPEET of AgNCs and AuNPs was inhibited when miRNA was added to produce the dumbbell shaped template by polymerase. The template could promote synthesis of AgNCs, resulting in replacement and subsequently recycling of the target molecule for signal amplification. In comparison with the traditional method of miRNA detection with commercial RT-PCR kits, this method avoided the process of reverse transcription and was easy to perform. In addition, this method with a detection limit of 2. 5×10-11 mol/L was cost-effective, label-free, and highly selective for detecting miRNA, and could be applied to the analysis of miRNA in biological samples.
ABSTRACT
Objective To investigate the effects of glutathione protected gold nanoclusters (GSH-Au NCs) on HeLa cytotoxity.Methods Fluorescence intensity were measured on GSH-Au NCs containing medium treated cells using fluorescence spectrophotometer at different time points.GSH-Au NCs uptake by HeLa cells at 1,2,6,12 and 24 h were investigated through fluorescent spectrophotometer.In vivo tumor uptake was also investigated on BALB/c tumor-bearing mice through inductively coupled plasma mass spectrometry (ICP-MS) at 24 h after intraperitoneal injection of 0.2 ml GSH-Au NCs (3 mmol/L) and distilled water (control group) respectively.The cytotoxicity of GSH-Au NCs at different doses (0.003-0.3 mmol/L) was tested at 24 and 48 h using MTT assay after interaction with HeLa cells.Results The uptake efficiency of GSH-Au NCs by HeLa cells kept increasing and reached maximum of 73.13％ at 24 h.The results of tumor-bearing mice indicated that the tumor tissue had higher uptake efficiency after 24 h (320±15) ng/g than that of control group (intraperitoneal injection of distilled water),and the difference was stastically significant (P＜0.05).HeLa cells were treated with different concentrations of GSH-Au NCs for 24 h,and GSHAu NCs had a slight effect on cell viability.With the increase of GSH-Au NCs dose,the inhibition effects on growth of HeLa cells enhanced.The cell activity of HeLa cells treated with 0.3 mmol/L GSH-Au NCs for 24 h reduced to 86％compared with that of control group (the concentration of GSH-Au NCs was 0) (P＜0.05),while there was no significant difference between the survival rate of different concentrations of GSH-Au NCs group and the control group for 48 h.Conclusions GSH-Au NCs have neglectable cytotoxity on HeLa cells even though both in vitro and in vivo uptake are high.GSH-Au NCs are suitable for biomedical application such as imaging,drug loading and targeted drug delivery.
ABSTRACT
Novel optical materials are crucial for environmental monitoring. Metal nanoclusters ( metal NCs) , typically consisting of several to tens of metal atoms, have attracted more and more attention for recent years. Due to their ultrasmall size, strong fluorescence, low toxicity, excellent stability and unique core-shell structure, metal NCs have been considered as promising optical materials for the construction of excellent fluorescent sensors. In this review, we mainly focus on the recent progress in their applications in environmental monitoring, including the detection of pH, heavy metal ions, inorganic anions and nitroaromatic explosives.