Facile Synthesis of Biocompatible Fluorescent Nanoparticles for Cellular Imaging and Targeted Detection of Cancer Cells

Advancements in Assessments of Bio-Tissue Engineering and Viable Cell Delivery Matrices Using Bile Acid-Based Pharmacological Biotechnologies

The utilisation of bioartificial organs is of significant interest to many due to their versatility in treating a wide range of disorders. Microencapsulation has a potentially significant role in such organs. In order to utilise microcapsules, accurate characterisation and analysis is required to assess their properties and suitability. Bioartificial organs or transplantable microdevices must also account for immunogenic considerations, which will be discussed in detail. One of the most characterized cases is the investigation into a bioartificial pancreas, including using microencapsulation of islets or other cells, and will be the focus subject of this review. Overall, this review will discuss the traditional and modern technologies which are necessary for the characterisation of properties for transplantable microdevices or organs, summarizing analysis of the microcapsule itself, cells and finally a working organ. Furthermore, immunogenic considerations of such organs are another important aspect which is addressed within this review. The various techniques, methodologies, advantages, and disadvantages will all be discussed. Hence, the purpose of this review is providing an updated examination of all processes for the analysis of a working, biocompatible artificial organ.

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.

pDNA conjugated with citrate capped silver nanoparticles towards ultrasensitive bio-assay of haemophilus influenza in human biofluids: A novel optical biosensor

A sensitive and specific approach was developed for the determination of Haemophilus influenza using DNA based bio-assay. In this study, citrate capped silver nanoparticle was synthesized and employed for bioconjugation with pDNA toward target sequences detection. In this study, synthesized probe (SH-5'-AAT TTT CCA ACT TTT TCA CCT GCA T-3') of Haemophilus influenza was detected with great sensitivity and selectivity after hybridization with cDNA (5'-ATG CAG GTG AAA AAG TTG GAA AAT T-3'). Regarding to the obtained results, the low limit of quantification (LLOQ) of DNA sample was 1 ZM using 15 μL of probe and 200 μL of Cit/AgNPs. According to ultra-sensitivity of the fabricated optical DNA-based bio-assay, it has potential for bacterial determination both in clinical and environmental specimens. To evaluate the selectivity of developed DNA based biosensor, three mismatch sequences were applied. Finally, the designed genosensor is a significant diagnostic strategy for detection of Haemophilus influenza with great selectivity.

High resolution tracking of macrophage cells in deep organs and lymphatics using fluorescent polymer dots

In vivo cell tracking can provide information on cell migration and accumulation in the organs. Here, both folate and amino modified polymer dots were synthesized and screened for in vitro and in vivo tracking of macrophage Ana-1 cells. Flow cytometry analysis demonstrated that prepared polymer dots showed cellular uptake of approximately 98% within a short incubation time of 2 h, and these polymer dots maintained a cell labeling rate over 97% after 2 d. Moreover, a CCK-8 assay suggested that these polymer dots increased Ana-1 cell viabilities up to 110% at concentrations from 5 to 50 μg mL-1. Furthermore, the in vivo real time imaging of labelled Ana-1 cells in the alveolus of lung and lymph nodes were clearly detected by probe-based confocal laser endomicroscopy (pCLE). This study demonstrates a unique approach using polymer dots for real-time high resolution tracking of macrophage cells in deep organs and the lymphatic system.

3D quantum theranosomes: a new direction for label-free theranostics

Quantum-scale materials offer great potential in the field of cancer theranostics. At present, quantum materials are severely limited due to 0D & 1D materials lacking biocompatibility, resulting in coated materials with labelled tags for fluorescence excitation. In addition, the application of magnetic quantum materials has not been reported to date for cancer theranostics. In this current research study, we introduce the concept of applying nickel-based magnetic 3D quantum theranosomes for label-free broadband fluorescence enhancement and cancer therapy. To begin with, we present two (primary and secondary) distinct quantum theranosomes for cancer detection and differentiation (HeLa & MDAMB-231) from mammalian fibroblast cells. The primary theranosomes exhibit a metal enhanced fluorescence (MEF) property through localized surface plasmon resonance to act as cancer detectors, whereas the secondary theranosomes act as cancer differentiators through the fluorescence quenching of HeLa cancer cells. Apart from the above, the synthesized magnetic quantum theranosomes introduced therapeutic functionality wherein the theranosomes mimicked a tumor microenvironment by selectively accelerating the proliferation of mammalian fibroblasts cells while at the same time inducing cancer therapy. These quantum theranosomes were synthesized using femtosecond pulse laser ablation and self-assembled to form an interconnected 3D structure. The 3D architecture and the physicochemical properties of the laser synthesized quantum theranosomes closely resembled a tumor microenvironment. Furthermore, we anticipate that our current recorded findings can shed further light upon these unique magnetic quantum theranosomes as potential contenders towards opening an entirely new direction in the field of cancer theranostics.

Cu@Au(Ag)/Pt nanocomposite as peroxidase mimic and application of Cu@Au/Pt in colorimetric detection of glucose and l-cysteine

Nanomaterial-based artificial peroxidase has attracted extensive interests due to their distinct advantages over natural counterpart. Cu@Au/Pt and Cu@Ag/Pt nanocomposite with rambutan-like structure were prepared and discovered to function like peroxidase, which was illustrated by catalyzing the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) accompanied with a blue color change. Steady-state investigation indicates that the catalytic kinetics of Cu@Au/Pt and Cu@Ag/Pt all followed typical Michaelis–Menten behaviors and Cu@Au/Pt showed a strong affinity for H₂O₂, while Cu@Ag/Pt showed strong affinity for TMB. The color change and absorbance intensity strongly depend on the concentration of H₂O₂, thus the direct determination of H₂O₂ and indirect detection of glucose were demonstrated using Cu@Au/Pt with a detection limit of 1.5 μM and 6 μM, respectively. What is more important, the method was applied for detection of glucose in 50% fetal bovine serum with a detection limit of 80 μM, which is much lower than the lowest glucose content in blood for diabetes (7 mM). Moreover, the Cu@Au/Pt nanocomposite were also successfully applied for sensing l-cysteine because of the inhibition effect. Considering the good peroxidase-like activity and novel structure, Cu@Au(Ag)/Pt is expected to have a wide range of applications in bioassays and biocatalysis.

Cu@Au(Ag)/Pt nanocomposite possess good peroxidase-like activity and can be used for detection of glucose and l-cysteine.

Involvement of telomerase activity inhibition and telomere dysfunction in silver nanoparticles anticancer effects

AIM

To investigate the possible mechanisms of telomerase and telomere underlying the anticancer effects of silver nanoparticles (AgNPs).

MATERIALS & METHODS

25nm polyvinylpyrrolidone-coated AgNPs were used. The telomerase activity and telomere function were evaluated. The anticancer effects of AgNPs were gauged with cell viability assay under different statement of telomerase and telomere.

RESULTS & CONCLUSION

AgNPs could inhibit telomerase activity and lead to telomere shortening and dysfunction. Overexpression of telomerase attenuated the anticancer activity of AgNPs, whereas downregulation of telomerase activity or dysfunction of the telomere enhanced the cytotoxicity of AgNPs in HeLa cells. Our findings provided strong evidence that the anticancer effects of AgNPs were mediated via interference with the telomerase/telomere.

Distance dependent fluorescence quenching and enhancement of gold nanoclusters by gold nanoparticles

The interaction between fluorescent gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) has been investigated. It was observed that the fluorescence of AuNCs was remarkably quenched when direct contact with AuNPs. The fluorescence quenching of AuNCs by AuNPs was dynamic quenching and exhibited size-dependent property. A larger size of AuNPs displayed a stronger quenching effect and gave a larger quenching constant. When a silica spacer shell was introduced between AuNPs and AuNCs, a fluorescence enhancement of AuNCs by Au@SiO₂ NPs was observed. The fluorescence enhancement was strongly dependent on the separation distance between the AuNPs and the AuNCs. A maximal enhancement of 3.72 times was observed when Au@SiO₂ NPs have a silica shell thickness of 12nm. This nanocomposite consisting of relatively nontoxic AuNPs and AuNCs may have a potential application in developing novel fluorescent sensor.

The Decline in Vitamin Research Funding: A Missed Opportunity?

Background: The National Nutrition Research Roadmap has called for support of greater collaborative, interdisciplinary research for multiple areas of nutrition research. However, a substantial reduction in federal funding makes responding to these calls challenging. Objectives: The objectives of this study were to examine temporal trends in research funding and to discuss the potential consequences of these trends. Methods: We searched the NIH RePORTER database to identify NIH research grants and USASpending to identify National Science Foundation and USDA research grants awarded from 1992 to 2015. We focused on those that pertained to vitamin research. For the years 2000 to 2015, we examined funding trends for different vitamins, including vitamins A, B (one-carbon B-vitamins were considered separately from other B-vitamins), C, D, E, and K. Results: From 1992 to 2015, total federal research spending increased from ∼$14 to $45 billion (2016 US dollars). Although vitamin research spending increased from ∼$89 to $95 million, the proportion of grants awarded for vitamin research declined by more than two-thirds, from 0.65% in 1992 to 0.2% in 2015. Federal agencies awarded 6035 vitamin research grants over the time period, with vitamin A associated with the most research projects per year on average (n = 115) and vitamin K the fewest (n = 8). Vitamin D research projects were associated with the greatest average yearly project value ($34.8 million). Conclusions: Vitamin research has faced a disproportionate decline in research funding from 1992 to 2015. Insufficient federal research funding streams risk stalling progress in vitamin research and leaving important advancements unrealized.

Synthesis of Cu-Nanoparticle Hydrogel with Self-Healing and Photothermal Properties

Copper (Cu) nanoparticles possess unusual electrical, thermal, and optical properties. However, applications of these materials are often limited by their tendency to oxidize. We prepared Cu nanoparticles by a simple polyol method, with a good control over the particle size. The reaction required no inert atmosphere or surfactant agents. The as-prepared Cu nanoparticles showed good resistance to oxidation in solution. These Cu nanoparticles were then incorporated into a biocompatible polysaccharide hydrogel, which further stabilized the nanoparticles. The hybrid hydrogel exhibited a rapid self-healing ability. Because of the excellent photothermal conversion properties of the embedded Cu nanoparticles, the hybrid hydrogel showed rapid temperature elevation under laser irradiation. The hybrid hydrogel showed limited cytotoxicity; however, under laser irradiation the hydrogel displayed antibacterial properties owing to the heating effects. This study demonstrates that our hybrid hydrogel may have applications in biomedical fields and photothermal therapy.

Stimuli-responsive multifunctional glyconanoparticle platforms for targeted drug delivery and cancer cell imaging

Targeted bioimaging or chemotherapeutic drug delivery to achieve the desired therapeutic effects while minimizing side effects has attracted considerable research attention and remains a clinical challenge. Presented herein is a multi-component delivery system based on carbohydrate-functionalized gold nanoparticles conjugated with a fluorophore or prodrug. The system leverages active targeting based on carbohydrate-lectin interactions and release of the payload by biological thiols. Cell-type specific delivery of the activatable fluorophore was examined by confocal imaging on HepG2 cells, and displays distinct selectivity towards HepG2 cells over HeLa and NIH3T3 cells. The system was further developed into a drug delivery vehicle with camptothecin (CPT) as a model drug. It was demonstrated that the complex exhibits similar cytotoxicity to that of free CPT towards HepG2 cells, and is significantly less cytotoxic to normal HDF and NIH3T3 cells, indicating excellent specificity. The delivery vehicle itself exhibits excellent biocompatibility and offers an attractive strategy for cell-type specific delivery depending on the carbohydrates conjugated in the system.

Folic acid-conjugated carbon dots as green fluorescent probes based on cellular targeting imaging for recognizing cancer cells

Green fluorescent CDs using the natural product dandelion as a carbon source were covalently conjugated with folate to differentiate cancer cells from normal cells.

An emission-tunable fluorescent organic molecule for specific cellular imaging

A color-tunable fluorescent molecule was synthesized and applied in specific lysosomal imaging.