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Silver Nanoparticle Coated Bioactive Glasses--Composites with Dex/CMC Hydrogels: Characterization, Solubility, and In Vitro Biological Studies

Wren AW, Hassanzadeh P, Placek LM, Keenan TJ, Coughlan A, Boutelle LR, et al.

Macromol Biosci, 2015 Aug;15(8):1146-58.
PMID: 25923463 DOI: 10.1002/mabi.201500109

Silver (Ag) coated bioactive glass particles (Ag-BG) were formulated and compared to uncoated controls (BG) in relation to glass characterization, solubility and microbiology. X-ray diffraction (XRD) confirmed a crystalline AgNP surface coating while ion release studies determined low Ag release (<2 mg/L). Cell culture studies presented increased cell viability (127 and 102%) with lower liquid extract (50 and 100 ml/ml) concentrations. Antibacterial testing of Ag-BG in E. coli, S. epidermidis and S. aureus significantly reduced bacterial cell viability by 60-90%. Composites of Ag-BG/CMC-Dex Hydrogels were formulated and characterized. Agar diffusion testing was conducted where Ag-BG/hydrogel composites produced the largest inhibition zones of 7 mm (E. coli), 5 mm (S. aureus) and 4 mm (S. epidermidis).

Matched MeSH terms: Metal Nanoparticles/chemistry*
Fulltext Colorimetric biosensing of targeted gene sequence using dual nanoparticle platforms

Thavanathan J, Huang NM, Thong KL

Int J Nanomedicine, 2015;10:2711-22.
PMID: 25897217 DOI: 10.2147/IJN.S74753

We have developed a colorimetric biosensor using a dual platform of gold nanoparticles and graphene oxide sheets for the detection of Salmonella enterica. The presence of the invA gene in S. enterica causes a change in color of the biosensor from its original pinkish-red to a light purplish solution. This occurs through the aggregation of the primary gold nanoparticles-conjugated DNA probe onto the surface of the secondary graphene oxide-conjugated DNA probe through DNA hybridization with the targeted DNA sequence. Spectrophotometry analysis showed a shift in wavelength from 525 nm to 600 nm with 1 μM of DNA target. Specificity testing revealed that the biosensor was able to detect various serovars of the S. enterica while no color change was observed with the other bacterial species. Sensitivity testing revealed the limit of detection was at 1 nM of DNA target. This proves the effectiveness of the biosensor in the detection of S. enterica through DNA hybridization.

Matched MeSH terms: Metal Nanoparticles/chemistry*
TiO₂ nanoparticle transport and retention through saturated limestone porous media under various ionic strength conditions

Esfandyari Bayat A, Junin R, Derahman MN, Samad AA

Chemosphere, 2015 Sep;134:7-15.
PMID: 25889359 DOI: 10.1016/j.chemosphere.2015.03.052

The impact of ionic strength (from 0.003 to 500mM) and salt type (NaCl vs MgCl2) on transport and retention of titanium dioxide (TiO2) nanoparticles (NPs) in saturated limestone porous media was systematically studied. Vertical columns were packed with limestone grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolent-visible spectrometry. Presence of NaCl and MgCl2 in the suspensions were found to have a significant influence on the electrokinetic properties of the NP aggregates and limestone grains. In NaCl and MgCl2 solutions, the deposition rates of the TiO2-NP aggregates were enhanced with the increase in ionic strength, a trend consistent with traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Furthermore, the NP aggregates retention increased in the porous media with ionic strength. The presence of salts also caused a considerable delay in the NPs breakthrough time. MgCl2 as compared to NaCl was found to be more effective agent for the deposition and retention of TiO2-NPs. The experimental results followed closely the general trends predicted by the filtration and DLVO calculations. Overall, it was found that TiO2-NP mobility in the limestone porous media depends on ionic strength and salt type.

Matched MeSH terms: Metal Nanoparticles/chemistry*
Immobilization of horseradish peroxidase on β-cyclodextrin-capped silver nanoparticles: Its future aspects in biosensor application

Karim Z, Khan MJ, Maskat MY, Adnan R

Prep Biochem Biotechnol, 2016 May 18;46(4):321-7.
PMID: 25830286 DOI: 10.1080/10826068.2015.1031389

This study aimed to work out a simple and high-yield procedure for the immobilization of horseradish peroxidase on silver nanoparticle. Ultraviolet-visible (UV-vis) and Fourier-transform infrared spectroscopy and transmission electron microscopy were used to characterize silver nanoparticles. Horseradish peroxidase was immobilized on β-cyclodextrin-capped silver nanoparticles via glutaraldehyde cross-linking. Single-cell gel electrophoresis (Comet assay) was also performed to confirm the genotoxicity of silver nanoparticles. To decrease toxicity, silver nanoparticles were capped with β-cyclodextrin. A comparative stability study of soluble and immobilized enzyme preparations was investigated against pH, temperature, and chaotropic agent, urea. The results showed that the cross-linked peroxidase was significantly more stable as compared to the soluble counterpart. The immobilized enzyme exhibited stable enzyme activities after repeated uses.

Matched MeSH terms: Metal Nanoparticles/chemistry*
Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties

Kuppusamy P, Ichwan SJ, Parine NR, Yusoff MM, Maniam GP, Govindan N

J Environ Sci (China), 2015 Mar 1;29:151-7.
PMID: 25766024 DOI: 10.1016/j.jes.2014.06.050

In this present study, we reported broccoli (Brassica oleracea L.) as a potential candidate for the synthesis of gold and silver nanoparticles (NPs) in green chemistry method. The synthesized metal nanoparticles are evaluated their antimicrobial efficacy against different human pathogenic organisms. The physico-chemical properties of gold nanoparticles were analyzed using different analytical techniques such as a UV-Vis spectrophotometer, Field Emission Scanning Electron Microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a Fourier Transform Infrared spectrophotometer. In addition, gold and silver NP antimicrobial efficacy was checked by disc diffusion assay. UV-Vis color intensity of the nanoparticles was shown at 540 and 450 nm for gold and silver nanoparticles respectively. Higher magnification of the Field Emission Scanning Electron Microscopy image shows the variable morphology of the gold nanoparticles such as spherical, rod and triangular shapes and silver nanoparticles were seen in spherical shapes. The average spherical size of the particles was observed in 24-38 nm for gold and 30-45 nm for silver NPs. X-ray diffraction pattern confirmed the presence of gold nanoparticles and silver nanoparticles which were crystalline in nature. Additionally, the functional metabolites were identified by the Fourier Transform Infrared spectroscopy. IR spectra revealed phenols, alcohols, aldehydes (sugar moieties), vitamins and proteins are present in the broccoli extract which are accountable to synthesize the nanoparticles. The synthesized gold and silver NPs inhibited the growth of the tested bacterial and fungal pathogens at the concentration of 50 μg/mL respectively. In addition, broccoli mediated gold and silver nanoparticles have shown potent antimicrobial activity against human pathogens.

Matched MeSH terms: Metal Nanoparticles/chemistry*
Gold nanostars-diagnosis, bioimaging and biomedical applications

Mousavi SM, Zarei M, Hashemi SA, Ramakrishna S, Chiang WH, Lai CW, et al.

Drug Metab Rev, 2020 05;52(2):299-318.
PMID: 32150480 DOI: 10.1080/03602532.2020.1734021

Gold Nanostars (GNS) have attracted tremendous attention toward themselves owing to their multi-branched structure and unique properties. These state of the art metallic nanoparticles possess intrinsic features like remarkable optical properties and exceptional physiochemical activities. These star-shaped gold nanoparticles can predominantly be utilized in biosensing, photothermal therapy, imaging, surface-enhanced Raman spectroscopy and target drug delivery applications due to their low toxicity and extraordinary optical features. In the current review, recent approaches in the matter of GNS in case of diagnosis, bioimaging and biomedical applications were summarized and reported. In this regard, first an overview about the structure and general properties of GNS were reported and thence detailed information regarding the diagnostic, bioimaging, photothermal therapy, and drug delivery applications of such novel nanomaterials were presented in detail. Summarized information clearly highlighting the superior capability of GNS as potential multi-functional materials for biomedical applications.

Matched MeSH terms: Metal Nanoparticles/chemistry*
Fulltext Cobalt nanoparticles as novel nanotherapeutics against Acanthamoeba castellanii

Anwar A, Numan A, Siddiqui R, Khalid M, Khan NA

Parasit Vectors, 2019 Jun 03;12(1):280.
PMID: 31159839 DOI: 10.1186/s13071-019-3528-2

BACKGROUND: Species of Acanthamoeba are facultative pathogens which can cause sight threatening Acanthamoeba keratitis and a rare but deadly brain infection, granulomatous amoebic encephalitis. Due to conversion of Acanthamoeba trophozoites to resistant cyst stage, most drugs are found to be ineffective at preventing recurrence of infection. This study was designed to test the antiacanthamoebic effects of different cobalt nanoparticles (CoNPs) against trophozoites and cysts, as well as parasite-mediated host cell cytotoxicity.
METHODS: Three different varieties of CoNPs were synthesized by utilizing hydrothermal and ultrasonication methods and were thoroughly characterized by X-ray diffraction and field emission scanning electron microscopy. Amoebicidal, encystation, excystation, and host cell cytopathogenicity assays were conducted to study the antiacanthamoebic effects of CoNPs.
RESULTS: The results of the antimicrobial evaluation revealed that cobalt phosphate Co3(PO4)2 hexagonal microflakes, and 100 nm large cobalt hydroxide (Co(OH)2) nanoflakes showed potent amoebicidal activity at 100 and 10 µg/ml against Acanthamoeba castellanii as compared to granular cobalt oxide (Co3O4) of size 35-40 nm. Furthermore, encystation and excystation assays also showed consistent inhibition at 100 µg/ml. CoNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release without causing significant damage to human cells when treated alone.
CONCLUSIONS: To our knowledge, these findings determined, for the first time, the effects of composition, size and morphology of CoNPs against A. castellanii. Co3(PO4)2 hexagonal microflakes showed the most promising antiamoebic effects as compared to Co(OH)2 nanoflakes and granular Co3O4. The results reported in the present study hold potential for the development of antiamoebic nanomedicine.

Matched MeSH terms: Nanoparticles/chemistry*
Central composite designed formulation, characterization and in vitro cytotoxic effect of erlotinib loaded chitosan nanoparticulate system

Pandey P, Chellappan DK, Tambuwala MM, Bakshi HA, Dua K, Dureja H

Int J Biol Macromol, 2019 Dec 01;141:596-610.
PMID: 31494160 DOI: 10.1016/j.ijbiomac.2019.09.023

The most common cause of deaths due to cancers nowadays is lung cancer. The objective of this study was to prepare erlotinib loaded chitosan nanoparticles for their anticancer potential. To study the effect of formulation variables on prepared nanoparticles using central composite design. Erlotinib loaded chitosan nanoparticles were prepared by ionic gelation method using probe sonication technique. It was found that batch NP-7 has a maximum loading capacity and entrapment efficiency with a particle size (138.5 nm) which is ideal for targeting solid tumors. Analysis of variance was applied to the particle size, entrapment efficiency and percent cumulative drug release to study the fitting and the significance of the model. The batch NP-7 showed 91.57% and 39.78% drug release after 24 h in 0.1 N hydrochloric acid and Phosphate Buffer (PB) pH 6.8, respectively. The IC50 value of NP-7 evaluated on A549 Lung cancer cells was found to be 6.36 μM. The XRD of NP-7 displayed the existence of erlotinib in the amorphous pattern. The optimized batch released erlotinib slowly in comparison to the marketed tablet formulation. Erlotinib loaded chitosan nanoparticles were prepared successfully using sonication technique with suitable particle size, entrapment efficiency and drug release. The formulated nanoparticles can be utilized for the treatment of lung cancer.

Matched MeSH terms: Nanoparticles/chemistry*
Fulltext Controlled synthesis of iron oxyhydroxide (FeOOH) nanoparticles using secretory compounds from Chlorella vulgaris microalgae

Ghanbariasad A, Taghizadeh SM, Show PL, Nomanbhay S, Berenjian A, Ghasemi Y, et al.

Bioengineered, 2019 12;10(1):390-396.
PMID: 31495263 DOI: 10.1080/21655979.2019.1661692

FeOOH nanoparticles are commonly synthesized at very high temperature and pressure that makes the process energy consuming and non-economic. Recently, novel approaches were developed for the fabrication of these particles at room temperature. But, the main problem with these methods is that the prepared structures are aggregates of ultra-small nanoparticles where no intact separate nanoparticles are formed. In this study, for the first time, secretory compounds from Chlorella vulgaris cells were employed for the controlled synthesis of FeOOH nanoparticles at room atmosphere. Obtained particles were found to be goethite (α-FeO(OH)) crystals. Controlled synthesis of FeOOH nanoparticles resulted in uniform spherical nanoparticles ranging from 8 to 17 nm in diameter with 12.8 nm mean particle size. Fourier-transform infrared and elemental analyses were indicated that controlled synthesized nanoparticles have not functionalized with secretory compounds of C. vulgaris, and these compounds just played a controlling role over the synthesis reaction.

Matched MeSH terms: Nanoparticles/chemistry*
Immunological axis of curcumin-loaded vesicular drug delivery systems

Chellappan DK, Ng ZY, Wong JY, Hsu A, Wark P, Hansbro N, et al.

Future Med Chem, 2018 04 01;10(8):839-844.
PMID: 29620416 DOI: 10.4155/fmc-2017-0245

Several vesicular systems loaded with curcumin have found their way in the therapeutic applications of several diseases, primarily acting through their immunological pathways. Such systems use particles at a nanoscale range, bringing about their intended use through a range of complex mechanisms. Apart from delivering drug substances into target tissues, these vesicular systems also effectively overcome problems like insolubility and unequal drug distribution. Several mechanisms are explored lately by different workers, and interest over vesicular curcumin has been renewed in the past decade. This commentary discusses several immunological targets in which curcumin is employed in a vesicular form.

Matched MeSH terms: Nanoparticles/chemistry
Recent Progress in Delivery of Therapeutic and Imaging Agents Utilizing Organic-Inorganic Hybrid Nanoparticles

Haque ST, Chowdhury EH

Curr Drug Deliv, 2018;15(4):485-496.
PMID: 29165073 DOI: 10.2174/1567201814666171120114034

BACKGROUND: Delivery of conventional small molecule drugs and currently evolving nucleic acid-based therapeutics, such as small interfering RNAs (siRNAs) and genes, and contrast agents for high resolution imaging, to the target site of action is highly demanding to increase the therapeutic and imaging efficacy while minimizing the off-target effects of the delivered molecules, as well as develop novel therapeutic and imaging approaches.
METHODS: We have undertaken a structured search for peer-reviewed research and review articles predominantly indexed in PubMed focusing on the organic-inorganic hybrid nanoparticles with evidence of their potent roles in intracellular delivery of therapeutic and imaging agents in different animal models.
RESULTS: Organic-inorganic hybrid nanoparticles offer a number of advantages by combining the unique properties of the organic and inorganic counterparts, thus improving the pharmacokinetic behavior and targetability of drugs and contrast agents, and conferring the exclusive optical and magnetic properties for both therapeutic and imaging purposes. Different polymers, lipids, dendrimers, peptides, cell membranes, and small organic molecules are attached via covalent or non-covalent interactions with diverse inorganic nanoparticles of gold, mesoporous silica, magnetic iron oxide, carbon nanotubes and quantum dots for efficient drug delivery and imaging purposes.
CONCLUSION: We have thus highlighted here the progress made so far in utilizing different organicinorganic hybrid nanoparticles for in vivo delivery of anti-cancer drugs, siRNA, genes and imaging agents.

Matched MeSH terms: Nanoparticles/chemistry*
Carbon nanotube scaffolds as emerging nanoplatform for myocardial tissue regeneration: A review of recent developments and therapeutic implications

Gorain B, Choudhury H, Pandey M, Kesharwani P, Abeer MM, Tekade RK, et al.

Biomed Pharmacother, 2018 Aug;104:496-508.
PMID: 29800914 DOI: 10.1016/j.biopha.2018.05.066

Myocardial infarction (cardiac tissue death) is among the most prevalent causes of death among the cardiac patients due to the inability of self-repair in cardiac tissues. Myocardial tissue engineering is regarded as one of the most realistic strategies for repairing damaged cardiac tissue. However, hindrance in transduction of electric signals across the cardiomyocytes due to insulating properties of polymeric materials worsens the clinical viability of myocardial tissue engineering. Aligned and conductive scaffolds based on Carbon nanotubes (CNT) have gained remarkable recognition due to their exceptional attributes which provide synthetic but viable microenvironment for regeneration of engineered cardiomyocytes. This review presents an overview and critical analysis of pharmaceutical implications and therapeutic feasibility of CNT based scaffolds in improving the cardiac tissue regeneration and functionality. The expository analysis of the available evidence revealed that inclusion of single- or multi-walled CNT into fibrous, polymeric, and elastomeric scaffolds results in significant improvement in electrical stimulation and signal transduction through cardiomyocytes. Moreover, incorporation of CNT in engineering scaffolds showed a greater potential of augmenting cardiomyocyte proliferation, differentiation, and maturation and has improved synchronous beating of cardiomyocytes. Despite promising ability of CNT in promoting functionality of cardiomyocytes, their presence in scaffolds resulted in substantial improvement in mechanical properties and structural integrity. Conclusively, this review provides new insight into the remarkable potential of CNT aligned scaffolds in improving the functionality of engineered cardiac tissue and signifies their feasibility in cardiac tissue regenerative medicines and stem cell therapy.

Matched MeSH terms: Nanoparticles/chemistry*
Impact of PEGylated Nanoparticles on Tumor Targeted Drug Delivery

Mozar FS, Chowdhury EH

Curr Pharm Des, 2018;24(28):3283-3296.
PMID: 30062957 DOI: 10.2174/1381612824666180730161721

PEG-functionalized nanoparticles as carriers of chemotherapeutics agents have been explored with notable successes in preclinical and clinical stages of cancer treatment, with some already approved by FDA, namely PEGylated liposomes and polymers. Half-life extension of therapeutic agents through PEGylation process improves their pharmacokinetic (PK) profiles, thereby reducing their dosing frequency. Protein corona composition of PEGylated nanoparticles (NPs) confers a tremendous influence on their surface characteristics which directly impact tumor accumulation and clearance properties of the drugs. By controlling the size and complexity of PEG molecules, as well as by attaching targeting moieties, the surface characteristics of NPs can be manipulated to improve their tumor uptake without sacrificing the circulation time. This review focuses on design and applications of PEGylated NPs for tumor targeted drug delivery in animal models and clinical setting.

Matched MeSH terms: Nanoparticles/chemistry*
Fulltext Potential Antimicrobial Applications of Chitosan Nanoparticles (ChNP)

Rozman NAS, Tong WY, Leong CR, Tan WN, Hasanolbasori MA, Abdullah SZ

J Microbiol Biotechnol, 2019 Jul 28;29(7):1009-1013.
PMID: 31288302 DOI: 10.4014/jmb.1904.04065

Polymeric nanoparticles are widely used for drug delivery due to their biodegradability property. Among the wide array of polymers, chitosan has received growing interest among researchers. It was widely used as a vehicle in polymeric nanoparticles for drug targeting. This review explored the current research on the antimicrobial activity of chitosan nanoparticles (ChNP) and the impact on the clinical applications. The antimicrobial activities of ChNP were widely reported against bacteria, fungi, yeasts and algae, in both in vivo and in vitro studies. For pharmaceutical applications, ChNP were used as antimicrobial coating for promoting wound healing, preventing infections and combating the rise of infectious disease. Besides, ChNP also exhibited significant inhibitory on foodborne microorganisms, particularly on fruits and vegetables. It is noteworthy that ChNP can be also applied to deliver antimicrobial drugs, which further enhance the efficiency and stability of the antimicrobial agent. The present review addresses the potential antimicrobial applications of ChNP from these few aspects.

Matched MeSH terms: Nanoparticles/chemistry*
A DNA based visual and colorimetric aggregation assay for the early growth factor receptor (EGFR) mutation by using unmodified gold nanoparticles

Ramanathan S, Gopinath SCB, Arshad MKM, Poopalan P, Anbu P

Mikrochim Acta, 2019 07 18;186(8):546.
PMID: 31321546 DOI: 10.1007/s00604-019-3696-y

A genomic DNA-based colorimetric assay is described for the detection of the early growth factor receptor (EGFR) mutation, which is the protruding reason for non-small cell lung cancer. A DNA sequence was designed and immobilized on unmodified gold nanoparticles (GNPs). The formation of the respective duplex indicates the presence of an EGFR mutation. It is accompanied by the aggregation of the GNPs in the presence of monovalent ions, and it indicates the presence of an EGFR mutation. This is accompanied by a color change from red (520 nm) to purple (620 nm). Aggregation was evidenced by transmission electron microscopy, scanning electron microscopy and atomic force microscopy. The limit of detection is 313 nM of the mutant target strand. A similar peak shift was observed for 2.5 μM concentrations of wild type target. No significant peak shift was observed with probe and non-complementary DNA. Graphical abstract Schematic representation of high-specific genomic DNA sequence on gold nanoparticle (GNP) aggregation with sodium chloride (NaCl). It illustrates the detection method for EGFR mutation on lung cancer detection. Red and purple colors of tubes represent dispersed and aggregated GNP, respectively.

Matched MeSH terms: Metal Nanoparticles/chemistry*
Gellan gum incorporating titanium dioxide nanoparticles biofilm as wound dressing: Physicochemical, mechanical, antibacterial properties and wound healing studies

Ismail NA, Amin KAM, Majid FAA, Razali MH

Mater Sci Eng C Mater Biol Appl, 2019 Oct;103:109770.
PMID: 31349525 DOI: 10.1016/j.msec.2019.109770

In this work, the potential of titanium dioxide nanoparticles incorporated gellan gum (GG + TiO2-NPs) biofilm as wound dressing material was investigated. The GG + TiO2-NPs biofilm was prepared via evaporative casting technique and was characterized using FTIR, XRD, and SEM to study their physiochemical properties. The mechanical properties, swelling and water vapor transmission rate (WVTR) of biofilm was determined to comply with an ideal wound dressing material. In vitro and in vivo wound healing studies was carried out to evaluate the performance of GG + TiO2-NPs biofilm. In vitro wound healing was studied on 3 T3 mouse fibroblast cells for cell viability, cell proliferation, and scratch assay. The acridine orange/propidium iodide (AO/PI) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to evaluate the viability of cell and cell proliferation. Cell migration assay was analyzed using Essen BioScience IncuCyteTM Zoom system. In vivo wound healing via open excision wounds model on Sprague Dawley rat was studied within 14 days. The FT-IR spectra of GG + TiO2-NPs biofilm show main bands assigned to OH stretching, OH deformation, and TiO stretching modes. XRD pattern of GG + TiO2-NPs biofilm suggesting that TiO2-NPs was successfully incorporated in biofilm and well distributed on the surface as proved by SEM analysis. The GG + TiO2-NPs biofilm shows higher mechanical strength and swelling (3.76 ± 0.11 MPa and 1061 ± 6%) as compared to pure GG film (3.32 ± 0.08 Mpa and 902 ± 6%), respectively. GG + TiO2-NPs biofilm shows good antibacterial properties as 9 ± 0.25 mm and 11 ± 0.06 mm exhibition zone was observed against Staphylococcus aureus and Escherichia coli bacteria, respectively. While no exhibition zone was obtained for pure GG biofilm. GG + TiO2-NPs biofilm also demonstrated better cell-to-cell interaction properties, as it's promoted cell proliferation and cell migration to accelerate open excision wound healing on Sprague Dawley rat. The wound treated with GG + TiO2-NPs biofilm was healed within 14 days, on the other hand, the wound is still can be seen when it was treated with GG. However, GG and GG + TiO2-NPs biofilm show no cytotoxicity effects on mouse fibroblast cells.

Matched MeSH terms: Nanoparticles/chemistry*
Amplification-free and direct fluorometric determination of telomerase activity in cell lysates using chimeric DNA-templated silver nanoclusters

Lee ST, Rahman R, Muthoosamy K, Mohamed NAH, Su X, Tayyab S, et al.

Mikrochim Acta, 2019 01 09;186(2):81.
PMID: 30627857 DOI: 10.1007/s00604-018-3194-7

A fluorogenic probe has been developed for determination of telomerase activity using chimeric DNA-templated silver nanoclusters (AgNCs). The formation of AgNCs was investigated before (route A) and after (route B) telomerase elongation reaction. Both routes caused selective quenching of the yellow emission of the AgNCs (best measured at excitation/emission wavelength of 470/557 nm) in telomerase-positive samples. The quenching mechanism was studied using synthetically elongated DNA to mimic the telomerase-catalyzed elongation. The findings show that quenching is due to the formation of parallel G-quadruplexes with a -TTA- loop in the telomerase elongated products. The assay was validated using different cancer cell extracts, with intra- and interassay coefficients of variations of <9.8%. The limits of detection for MCF7, RPMI 2650 and HT29 cell lines are 15, 22 and 39 cells/μL. This represents a distinct improvement over the existing telomeric repeat amplification protocol (TRAP) assay in terms of time, sensitivity and cost. Graphical Abstract A method was developed using chimeric DNA-templated silver nanoclusters to detect telomerase activity directly in cell extracts. The sensitivity of this new method outperforms the traditional TRAP assay, and without the need for amplification.

Matched MeSH terms: Metal Nanoparticles/chemistry
Nanomedicines for cancer therapy: current status, challenges and future prospects

Bor G, Mat Azmi ID, Yaghmur A

Ther Deliv, 2019 02;10(2):113-132.
PMID: 30678550 DOI: 10.4155/tde-2018-0062

The emergence of nanomedicine as an innovative and promising alternative technology shows many advantages over conventional cancer therapies and provides new opportunities for early detection, improved treatment, and diagnosis of cancer. Despite the cancer nanomedicines' capability of delivering chemotherapeutic agents while providing lower systemic toxicity, it is paramount to consider the cancer complexity and dynamics for bridging the translational bench-to-bedside gap. It is important to conduct appropriate investigations for exploiting the tumor microenvironment, and achieving a more comprehensive understanding of the fundamental biological processes in cancer and their roles in modulating nanoparticle-protein interactions, blood circulation, and tumor penetration. This review provides an overview of the current cancer nanomedicines, the major challenges, and the future opportunities in this research area.

Matched MeSH terms: Nanoparticles/chemistry
Fulltext Influence of Sputtering Temperature of TiO2 Deposited onto Reduced Graphene Oxide Nanosheet as Efficient Photoanodes in Dye-Sensitized Solar Cells

Low FW, Chin Hock G, Kashif M, Samsudin NA, Chau CF, Indah Utami AR, et al.

Molecules, 2020 Oct 21;25(20).
PMID: 33096759 DOI: 10.3390/molecules25204852

Renewable solar energy is the key target to reduce fossil fuel consumption, minimize global warming issues, and indirectly minimizes erratic weather patterns. Herein, the authors synthesized an ultrathin reduced graphene oxide (rGO) nanosheet with ~47 nm via an improved Hummer's method. The TiO2 was deposited by RF sputtering onto an rGO nanosheet with a variation of temperature to enhance the photogenerated electron or charge carrier mobility transport for the photoanode component. The morphology, topologies, element composition, crystallinity as well as dye-sensitized solar cells' (DSSCs) performance were determined accordingly. Based on the results, FTIR spectra revealed presence of Ti-O-C bonds in every rGO-TiO2 nanocomposite samples at 800 cm-1. Besides, XRD revealed that a broad peak of anatase TiO2 was detected at ~25.4° after incorporation with the rGO. Furthermore, it was discovered that sputtering temperature of 120 °C created a desired power conversion energy (PCE) of 7.27% based on the J-V plot. Further increase of the sputtering temperature to 160 °C and 200 °C led to excessive TiO2 growth on the rGO nanosheet, thus resulting in undesirable charge recombination formed at the photoanode in the DSSC device.

Matched MeSH terms: Nanoparticles/chemistry
Fulltext In Vitro Evaluation of Curcumin-Encapsulated Chitosan Nanoparticles against Feline Infectious Peritonitis Virus and Pharmacokinetics Study in Cats

Ng SW, Selvarajah GT, Hussein MZ, Yeap SK, Omar AR

Biomed Res Int, 2020;2020:3012198.
PMID: 32596292 DOI: 10.1155/2020/3012198

Feline infectious peritonitis (FIP) is an important feline viral disease, causing an overridden inflammatory response that results in a high mortality rate, primarily in young cats. Curcumin is notable for its biological activities against various viral diseases; however, its poor bioavailability has hindered its potential in therapeutic application. In this study, curcumin was encapsulated in chitosan nanoparticles to improve its bioavailability. Curcumin-encapsulated chitosan (Cur-CS) nanoparticles were synthesised based on the ionic gelation technique and were spherical and cuboidal in shape, with an average particle size of 330 nm and +42 mV in zeta potential. The nanoparticles exerted lower toxicity in Crandell-Rees feline kidney (CrFK) cells and enhanced antiviral activities with a selective index (SI) value three times higher than that of curcumin. Feline-specific bead-based multiplex immunoassay and qPCR were used to examine their modulatory effects on proinflammatory cytokines, including tumour necrosis factor (TNF)α, interleukin- (IL-) 6, and IL-1β. There were significant decrements in IL-1β, IL-6, and TNFα expression in both curcumin and Cur-CS nanoparticles. Based on the multiplex immunoassay, curcumin and the Cur-CS nanoparticles could lower the immune-related proteins in FIP virus (FIPV) infection. The single- and multiple-dose pharmacokinetics profiles of curcumin and the Cur-CS nanoparticles were determined by high-performance liquid chromatography (HPLC). Oral delivery of the Cur-CS nanoparticles to cats showed enhanced bioavailability with a maximum plasma concentration (Cmax) value of 621.5 ng/mL. Incorporating chitosan nanoparticles to deliver curcumin improved the oral bioavailability and antiviral effects of curcumin against FIPV infection. This study provides evidence for the potential of Cur-CS nanoparticles as a supplementary treatment of FIP.

Matched MeSH terms: Nanoparticles/chemistry*

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