Bright Fluorescent Nanodiamonds:  No Photobleaching and Low Cytotoxicity

2005 ◽  
Vol 127 (50) ◽  
pp. 17604-17605 ◽  
Author(s):  
Shu-Jung Yu ◽  
Ming-Wei Kang ◽  
Huan-Cheng Chang ◽  
Kuan-Ming Chen ◽  
Yueh-Chung Yu
Keyword(s):  
Fluorescent Nanodiamonds ◽  
Low Cytotoxicity

scholarly journals Thermometric Characterization of Fluorescent Nanodiamonds Suitable for Biomedical Applications

2021 ◽  
Vol 11 (9) ◽  
pp. 4065
Author(s):  
Francisco Pedroza-Montero ◽  
Karla Santacruz-Gómez ◽  
Mónica Acosta-Elías ◽  
Erika Silva-Campa ◽  
Diana Meza-Figueroa ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Data Representation ◽  
Colour Centres ◽  
High Pressure High Temperature ◽  
Aqueous Environments ◽  
Fluorescent Nanodiamonds ◽  
Low Cytotoxicity ◽  
Scientific Fields ◽  
Potential Use

Nanodiamonds have been studied for several biomedical applications due to their inherent biocompatibility and low cytotoxicity. Recent investigations have shown perspectives in using fluorescent nanodiamonds as nanothermometers because of their optical properties’ dependence on temperature. Easy and accurate localized temperature sensing is essential in a wide variety of scientific fields. Our work demonstrated how the fluorescence spectrum of high-pressure high-temperature fluorescent nanodiamonds of three different sizes: 35 nm, 70 nm and 100 nm, changes with temperature within an important biological temperature range (25 °C to 60 °C). Taking advantage of this phenomenon, we obtained nanothermic scales (NS) from the zero phonon lines (ZPL) of the NV0 and NV− colour centres. In particular, the 100 nm-sized features the more intense fluorescence spectra whose linear dependence with temperature achieved 0.98 R2 data representation values for both NV0 and NV−. This model predicts temperature for all used nanodiamonds with sensitivities ranging from 5.73% °C−1 to 6.994% °C−1 (NV0) and from 4.14% °C−1 to 6.475% °C−1 (NV−). Furthermore, the non-cytotoxic interaction with HeLa cells tested in our study enables the potential use of fluorescence nanodiamonds to measure temperatures in similar nano and microcellular aqueous environments with a simple spectroscopic setup.

Mesoscopic gelation of chitosan and genipin at below critical concentrations

2017 ◽  
Author(s):  
Christoph Engwer ◽  
Ronja Loy ◽  
Ioannis S. Chronakis ◽  
Ana C. Mendes ◽  
Francisco M. Goycoolea
Keyword(s):  
Sol Gel ◽  
Crosslinking Agent ◽  
Small Deformation ◽  
Macroscopic Appearance ◽  
Critical Concentrations ◽  
Gelation Kinetics ◽  
Gardenia Jasminoides ◽  
Sol Gel Transition ◽  
Low Cytotoxicity ◽  
High Concentrations

Genipin is increasingly used as a crosslinking agent for chitosans due to its low cytotoxicity as a naturally occurring extract of the plant <i>Gardenia jasminoides</i>. Genipin reacts with the primary amino groups of chitosan to form blue hydrogels. We studied the gelation kinetics of different chitosans varying in their properties (molar mass 34 000-213 000 g mol<sup>-1</sup>, degree of acetylation 9-20%) and genipin in detail. We found that critical sol-gel transition times obtained from dynamic light scattering were in good agreement with the results obtained by small deformation oscillatory rheometry and microviscosimetry at high concentrations of chitosan. However, at below critical concentrations, we found a second regime of gelation that followed the same Ross-Murphy's gelation kinetics. The macroscopic appearance of these samples was a suspension of weak gel-like particles that were sensitive to mechanical forces. We believe that the material is a mesoscopic gel, as described for other polymers. To the best of our knowledge, this is the first time that this phenomenon has been described for the gelling system of chitosan and genipin.

Targeted Delivery of siRNA Therapeutics using Ligand Mediated Biodegradable Polymeric Nanocarriers

2018 ◽  
Vol 24 (16) ◽  
pp. 1788-1800 ◽  
Author(s):  
Kye-Soo Cho ◽  
Seo-Jin Hong ◽  
Min-Hye Ahn ◽  
Sukdeb Pal ◽  
Pill-Hoon Choung ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Delivery System ◽  
Targeted Delivery ◽  
Sirna Delivery ◽  
Public Health Issue ◽  
Magic Bullet ◽  
Bodily Fluids ◽  
Low Cytotoxicity ◽  
Genetic And Environmental Factors ◽  
Sirna Delivery System

Background: Cancer poses a major public health issue, is linked with high mortality rates across the world, and shows a strong interplay between genetic and environmental factors. To date, common therapeutics, including chemotherapy, immunotherapy, and radiotherapy, have made significant contributions to cancer treatment, although diverse obstacles for achieving the permanent “magic bullet” cure have remained. Recently, various anticancer therapeutic agents designed to overcome the limitations of these conventional cancer treatments have received considerable attention. One of these promising and novel agents is the siRNA delivery system; however, poor cellular uptake and altered siRNA stability in physiological environments have limited its use in clinical trials. Therefore, developing the ideal siRNA delivery system with low cytotoxicity, improved siRNA stability in the body’s circulation, and prevention of its rapid clearance from bodily fluids, is rapidly emerging as an innovative therapeutic strategy to combat cancer. Moreover, active targeting using ligand moieties which bind to over-expressed receptors on the surface of cancer cells would enhance the therapeutic efficiency of siRNA. Conclusion: In this review, we provide 1) an overview of the non-viral carrier associated with siRNA delivery for cancer treatment, and 2) a description of the five major cancer-targeting ligands.

Synthesis and Structure−Activity Relationship Studies of N-monosubstituted Aroylthioureas as Urease Inhibitors

2020 ◽  
Vol 16 ◽  
Author(s):  
Wei-Wei Ni ◽  
Hai-Lian Fang ◽  
Ya-Xi Ye ◽  
Wei-Yi Li ◽  
Li Liu ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Mammalian Cells ◽  
Intact Cell ◽  
Linear Regression Analysis ◽  
Positive Control ◽  
Acetohydroxamic Acid ◽  
Urease Inhibitors ◽  
Ic50 Value ◽  
Ic50 Values ◽  
Low Cytotoxicity

Background: Thiourea is a classical urease inhibitor usually as a positive control, and many N,N`-disubstituted thioureas have been determined as urease inhibitors. However, due to steric hindrance, N,N`-disubstituted thiourea motif could not bind urease as thiourea. On the contrary, N-monosubstituted thioureas with a tiny thiourea motif could theoretically bind into the active pocket as thiourea. Objective: A series of N-monosubstituted aroylthioureas were designed and synthesized for evaluation as urease inhibitors. Methods: Urease inhibition was determined by the indophenol method and IC50 values were calculated using computerized linear regression analysis of quantal log dose-probit functions. The kinetic parameters were estimated viasurface plasmon resonance (SPR) and by nonlinear regression analysis based on the mixed type inhibition model derived from Michaelis-Menten kinetics. Results: Compounds b2, b11and b19 reversibly inhibited urease with a mixed mechanism, and showed excellent potency against both cell-free urease and urease in intact cell, with IC50 values being 90-to 450-fold and 5-to 50-fold lower than the positive control acetohydroxamic acid, respectively. The most potent compound b11 showed IC50 value of 0.060 ±0.004μM against cell-free urease, which bound to urea binding site with a very low KDvalue (0.420±0.003nM) and a very long residence time (6.7 min). Compound b11was also demonstrated having very low cytotoxicity to mammalian cells. Conclusion: These results revealed that N-monosubstituted aroylthioureas clearly bind the active site of urease as expected, and represent a new class of urease inhibitors for the development of potential therapeutics against infections caused by ure-ase-containing pathogens.

scholarly journals The newly synthesized thiazole derivatives as potential antifungal compounds against Candida albicans

2021 ◽  
Author(s):  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Gumieniczek ◽  
Maria Malm ◽  
Krzysztof Z. Łączkowski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Cell Membrane ◽  
Mode Of Action ◽  
Thiazole Derivatives ◽  
Fungal Cell ◽  
Erythrocyte Lysis ◽  
Low Cytotoxicity ◽  
High Antifungal Activity

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract

scholarly journals Discovery and Optimization of Selective Inhibitors of Meprin α (Part I)

2021 ◽  
Vol 14 (3) ◽  
pp. 203 ◽  
Author(s):  
Shurong Hou ◽  
Juan Diez ◽  
Chao Wang ◽  
Christoph Becker-Pauly ◽  
Gregg B. Fields ◽  
...  
Keyword(s):  
Inhibitory Activity ◽  
De Novo ◽  
Selective Inhibitors ◽  
Preclinical Development ◽  
Starting Point ◽  
Good Starting Point ◽  
Parallel Screening ◽  
Low Cytotoxicity

Meprin α and β are zinc-dependent proteinases implicated in multiple diseases including cancers, fibrosis, and Alzheimer’s. However, until recently, only a few inhibitors of either meprin were reported and no inhibitors are in preclinical development. Moreover, inhibitors of other metzincins developed in previous years are not effective in inhibiting meprins suggesting the need for de novo discovery effort. To address the paucity of tractable meprin inhibitors we developed ultrahigh-throughput assays and conducted parallel screening of >650,000 compounds against each meprin. As a result of this effort, we identified five selective meprin α hits belonging to three different chemotypes (triazole-hydroxyacetamides, sulfonamide-hydroxypropanamides, and phenoxy-hydroxyacetamides). These hits demonstrated a nanomolar to micromolar inhibitory activity against meprin α with low cytotoxicity and >30-fold selectivity against meprin β and other related metzincincs. These selective inhibitors of meprin α provide a good starting point for further optimization.

scholarly journals Functionalization of Gold Nanostars with Cationic β-Cyclodextrin-Based Polymer for Drug Co-Loading and SERS Monitoring

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 261
Author(s):  
Orlando Donoso-González ◽  
Lucas Lodeiro ◽  
Álvaro E. Aliaga ◽  
Miguel A. Laguna-Bercero ◽  
Soledad Bollo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Colloidal Stability ◽  
Biomedical Application ◽  
Drug Loading ◽  
Gold Nanostars ◽  
Raman Optical Activity ◽  
Cationic Group ◽  
Low Cytotoxicity ◽  
Stability Limits ◽  
Zeta Potential Analysis

Gold nanostars (AuNSs) exhibit modulated plasmon resonance and have a high SERS enhancement factor. However, their low colloidal stability limits their biomedical application as a nanomaterial. Cationic β-cyclodextrin-based polymer (CCD/P) has low cytotoxicity, can load and transport drugs more efficiently than the corresponding monomeric form, and has an appropriate cationic group to stabilize gold nanoparticles. In this work, we functionalized AuNSs with CCD/P to load phenylethylamine (PhEA) and piperine (PIP) and evaluated SERS-based applications of the products. PhEA and PIP were included in the polymer and used to functionalize AuNSs, forming a new AuNS-CCD/P-PhEA-PIP nanosystem. The system was characterized by UV–VIS, IR, and NMR spectroscopy, TGA, SPR, DLS, zeta potential analysis, FE-SEM, and TEM. Additionally, Raman optical activity, SERS analysis and complementary theoretical studies were used for characterization. Minor adjustments increased the colloidal stability of AuNSs. The loading capacity of the CCD/P with PhEA-PIP was 95 ± 7%. The physicochemical parameters of the AuNS-CCD/P-PhEA-PIP system, such as size and Z potential, are suitable for potential biomedical applications Raman and SERS studies were used to monitor PhEA and PIP loading and their preferential orientation upon interaction with the surface of AuNSs. This unique nanomaterial could be used for simultaneous drug loading and SERS-based detection.

scholarly journals Exploiting DNA Endonucleases to Advance Mechanisms of DNA Repair

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 530
Author(s):  
Marlo K. Thompson ◽  
Robert W. Sobol ◽  
Aishwarya Prakash
Keyword(s):  
Dna Repair ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Gene Editing ◽  
Adaptive Immune System ◽  
Zinc Finger Nucleases ◽  
Specific Gene ◽  
Target Sequence ◽  
Transcription Activator ◽  
Low Cytotoxicity

The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.

scholarly journals Polysaccharide-Based Aerogel Production for Biomedical Applications: A Comparative Review

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1631
Author(s):  
Mariangela Guastaferro ◽  
Ernesto Reverchon ◽  
Lucia Baldino
Keyword(s):  
Tissue Regeneration ◽  
Supercritical Co2 ◽  
Biomedical Applications ◽  
Freeze Drying ◽  
Time Interval ◽  
Comparative Review ◽  
Biomedical Field ◽  
Low Cytotoxicity ◽  
Gel Preparation ◽  
Cell Adhesion And Proliferation

A comparative analysis concerning bio-based gels production, to be used for tissue regeneration, has been performed in this review. These gels are generally applied as scaffolds in the biomedical field, thanks to their morphology, low cytotoxicity, and high biocompatibility. Focusing on the time interval 2015–2020, the production of 3D scaffolds of alginate, chitosan and agarose, for skin and bone regeneration, has mainly been investigated. Traditional techniques are critically reviewed to understand their limitations and how supercritical CO2-assisted processes could overcome these drawbacks. In particular, even if freeze-drying represents the most widespread drying technique used to produce polysaccharide-based cryogels, supercritical CO2-assisted drying effectively allows preservation of the nanoporous aerogel structure and removes the organic solvent used for gel preparation. These characteristics are essential for cell adhesion and proliferation.

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