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Scientific Reports Oct 2022Chemically coated micro/nanoparticles are often used in medicine to enhance drug delivery and increase drug up-take into specific areas of the body. Using a recently...
Chemically coated micro/nanoparticles are often used in medicine to enhance drug delivery and increase drug up-take into specific areas of the body. Using a recently discovered spontaneous symmetry breaking propulsion mechanism, we demonstrate that chemically coated microparticles can swim through mucus solution under precise navigation and that certain functionalizations can dynamically change propulsion behavior. For this investigation biotin, Bitotin-PEG3-amine, and biotin chitosan were chemically functionalized onto the surfaces of magnetic microparticles using an avidin-biotin complex. These chemicals were chosen because they are used prolifically in drug delivery applications, with PEG and chitosan having well known mucoadhesive effects. Coated microparticles were then suspended in mucus synthesized from porcine stomach mucins and propelled using rotating magnetic fields. The relationship between different chemical coatings, microparticle velocity, and controllability were thoroughly explored and discussed. Results indicate that the biotinylated surface coatings altered the propulsion behavior of microparticles, with performance differences interlinked to both magnetic field properties and localized mucus properties. Precisely controlled drug carrying microparticles are envisioned to help supplant traditional drug delivery methods and enhance existing medical techniques utilizing micro/nanoparticles.
Topics: Swine; Animals; Chitosan; Avidin; Biotin; Drug Delivery Systems; Mucins; Amines; Magnetic Phenomena
PubMed: 36271100
DOI: 10.1038/s41598-022-21725-z -
Journal of Controlled Release :... Feb 2020Targeted drug delivery to joint tissues like cartilage remains a challenge that has prevented clinical translation of promising osteoarthritis (OA) drugs. Local...
Targeted drug delivery to joint tissues like cartilage remains a challenge that has prevented clinical translation of promising osteoarthritis (OA) drugs. Local intra-articular (IA) injections of drugs suffer from rapid clearance from the joint space and slow diffusive transport through the dense, avascular cartilage matrix comprised of negatively charged glycosaminoglycans (GAGs). Here we apply drug carriers that leverage electrostatic interactions with the tissue's high negative fixed charge density (FCD) for delivering small molecule drugs to cartilage cell and matrix sites. We demonstrate that a multi-arm cationic nano-construct of Avidin (mAv) with 28 sites for covalent drug conjugation can rapidly penetrate through the full thickness of cartilage in high concentration and have long intra-cartilage residence time in both healthy and arthritic cartilage via weak-reversible binding with negatively charged aggrecans. mAv's intra-cartilage mean uptake was found to be 112× and 33× the equilibration bath concentration in healthy and arthritic (50% GAG depleted) cartilage, respectively. mAv was conjugated with Dexamethasone (mAv-Dex), a broad-spectrum glucocorticoid, using a combination of hydrolysable ester linkers derived from succinic anhydride (SA), 3,3-dimethylglutaric anhydride (GA) and phthalic anhydride (PA) in 2:1:1 M ratio that enabled 50% drug release within 38.5 h followed by sustained release in therapeutic doses over 2 weeks. A single 10 μM low dose of controlled release mAv-Dex (2:1:1) effectively suppressed IL-1α-induced GAG loss, cell death and inflammatory response significantly better than unmodified Dex over 2 weeks in cartilage explant culture models of OA. With this multi-arm design, <1 μM Avidin was needed - a concentration which has been shown to be safe, preventing further GAG loss and cytotoxicity. A charge-based cartilage homing drug delivery platform like this can elicit disease modifying effects as well as facilitate long-term symptomatic pain and inflammation relief by enhancing tissue specificity and prolonging intra-cartilage residence time of OA drugs. This nano-construct thus has high translational potential for enabling intra-cartilage delivery of a broad array of small molecule OA drugs and their combinations to chondrocytes, enabling OA treatment with a single injection of low drug doses and eliminating toxicity issues associated with multiple high dose injections.
Topics: Avidin; Cartilage, Articular; Chondrocytes; Drug Carriers; Humans; Injections, Intra-Articular; Osteoarthritis
PubMed: 31843642
DOI: 10.1016/j.jconrel.2019.12.020 -
Proceedings of the National Academy of... Sep 1991One distinguishing feature of "life" is that the physical forces between biological molecules and membrane surfaces are often highly specific, in contrast to nonspecific...
One distinguishing feature of "life" is that the physical forces between biological molecules and membrane surfaces are often highly specific, in contrast to nonspecific interactions such as van der Waals, hydrophobic, and electrostatic (Coulombic) forces. We have used the surface-forces-apparatus technique to study the specific "lock and key" or "ligand-receptor" interaction between two model biomembrane surfaces in aqueous solution. The membranes were lipid bilayers supported on mica surfaces; one carrying streptavidin receptors, the other exposing biotin ligand groups. We found that, although no unusual or specific interaction occurs between two avidin or two biotin surfaces, an avidin and a biotin surface exhibit a very strong, very short-range (less than 1 nm) attraction and that the binding mechanism involves equally specific molecular rearrangements. The results also show that highly specific biological interactions such as are involved in immunological recognition and cell-cell contacts may be studied at the molecular level and in real time by the surface-forces-apparatus technique.
Topics: Aluminum Silicates; Avidin; Bacterial Proteins; Biophysical Phenomena; Biophysics; Biotin; In Vitro Techniques; Ligands; Membranes, Artificial; Protein Binding; Streptavidin
PubMed: 1896465
DOI: 10.1073/pnas.88.18.8169 -
PloS One 2013The fluorescence lifetimes of most red emitting organic probes are under 4 nanoseconds, which is a limiting factor in studying interactions and conformational dynamics...
The fluorescence lifetimes of most red emitting organic probes are under 4 nanoseconds, which is a limiting factor in studying interactions and conformational dynamics of macromolecules. In addition, the nanosecond background autofluorescence is a significant interference during fluorescence measurements in cellular environment. Therefore, red fluorophores with longer lifetimes will be immensely helpful. Azaoxa-triangulenium fluorophores ADOTA and DAOTA are red emitting small organic molecules with high quantum yield, long fluorescence lifetime and high limiting anisotropy. In aqueous environment, ADOTA and DAOTA absorption and emission maxima are respectively 540 nm and 556 nm, and 556 nm and 589 nm. Their emission extends beyond 700 nm. Both probes have the limiting anisotropy between 0.36-0.38 at their absorption peak. In both protic and aprotic solvents, their lifetimes are around 20 ns, making them among the longest-lived red emitting organic fluorophores. Upon labeling of avidin, streptavidin and immunoglobulin their absorption and fluorescence are red-shifted. Unlike in free form, the protein-conjugated probes have heterogeneous fluorescence decays, with the presence of both significantly quenched and unquenched populations. Despite the presence of significant local motions due to a flexible trimethylene linker, we successfully measured both intermediate nanosecond intra-protein motions and slower rotational correlation times approaching 100 ns. Their long lifetimes are unaffected by the cell membrane (hexadecyl-ADOTA) and the intra-cellular (DAOTA-Arginine) localization. Their long lifetimes also enabled successful time-gating of the cellular autofluorescence resulting in background-free fluorescence lifetime based images. ADOTA and DAOTA retain a long fluorescence lifetime when free, as protein conjugate, in membranes and inside the cell. Our successful measurements of intermediate nanosecond internal motions and long correlations times of large proteins suggest that these probes will be highly useful to study slower intra-molecular motions and interactions among macromolecules. The fluorescence lifetime facilitated gating of cellular nanosecond autofluorescence should be of considerable help in in vitro and in vivo applications.
Topics: Absorption; Animals; Anisotropy; Avidin; Buffers; Butyric Acid; Cell Line, Tumor; Endothelial Cells; Fluorescent Dyes; Heterocyclic Compounds, 4 or More Rings; Humans; Hydrogen-Ion Concentration; Immunoglobulin G; Rhodamines; Solvents; Spectrometry, Fluorescence; Staining and Labeling; Streptavidin; Temperature; Time Factors; Unilamellar Liposomes
PubMed: 23667570
DOI: 10.1371/journal.pone.0063043 -
Biomaterials May 2013The avidin-biotin system is a highly specific reaction that has been used in a wide range of biomedical applications, including surface modification and cell patterning....
The avidin-biotin system is a highly specific reaction that has been used in a wide range of biomedical applications, including surface modification and cell patterning. We systematically examined a number of avidin derivatives as the basis for a simple and cost effective tissue culture polystyrene substrate surface modification for human stem cell culture. Non-specific adhesion between human mesenchymal stem cells and various avidin derivatives, media conditions, and subsequent biotinylation reactions was quantified. We observed significant non-specific cell adhesion to avidin and strepthavidin, indicating that previous observations using this system may be artifactual. Seeding of cells in serum free media, blocking with bovine serum albumin, and the use of the avidin derivative neutravidin were all necessary for elimination of background adhesion. Neutravidin conjugated with biotinylated bsp-RGD(15) peptide provided the most robust cell adhesion, as well as the greatest increase in cell adhesion over background levels.
Topics: Amino Acid Sequence; Animals; Avidin; Biotin; Cattle; Cell Adhesion; Culture Media, Serum-Free; Hot Temperature; Humans; Mesenchymal Stem Cells; Molecular Sequence Data; Peptides; Serum Albumin, Bovine
PubMed: 23452388
DOI: 10.1016/j.biomaterials.2013.01.081 -
Journal of Fluorescence Jul 2004We report recent achievements in metal-enhanced fluorescence from our laboratory. Several fluorophore systems have been studied on metal particle-coated surfaces and in... (Review)
Review
We report recent achievements in metal-enhanced fluorescence from our laboratory. Several fluorophore systems have been studied on metal particle-coated surfaces and in colloid suspensions. In particular, we describe a distance dependent enhancement on silver island films (SIFs), release of self-quenching of fluorescence near silver particles, and the applications of fluorescence enhancement near metalized surfaces to bioassays. We discuss a number of methods for various shaped silver particle deposition on surfaces.
Topics: Algorithms; Avidin; Biotin; Colloids; DNA; Electrochemistry; Fluorescence; Fluorescence Resonance Energy Transfer; Fluorescent Dyes; Metals; Microscopy, Atomic Force; Nanostructures; Nanotechnology; Nucleic Acid Hybridization; Photochemistry; Serum Albumin, Bovine; Silver; Spectrometry, Fluorescence; Surface Properties
PubMed: 15617385
DOI: 10.1023/b:jofl.0000031824.48401.5c -
Poultry Science Feb 2015Probable involvement of avidin and avidin-related protein-2 (AVR2) in sperm viability in the sperm storage tubules of turkeys has been suggested. The high affinity of... (Randomized Controlled Trial)
Randomized Controlled Trial
Oral administration of supplementary biotin differentially influences the fertility rate and oviductal expression of avidin and avidin-related protein-2 in low- and high-fertility broiler line hens.
Probable involvement of avidin and avidin-related protein-2 (AVR2) in sperm viability in the sperm storage tubules of turkeys has been suggested. The high affinity of biotin to avidin and its analogs is also well documented. The present study aimed to determine the effect of oral biotin on reproductive performance and oviductal mRNA expression of avidin and AVR2 in 2 broiler hen lines with different fertility rates. Low-fertility (line B) and high-fertility (line D) hens (n=144) were randomly allotted to receive 0 (T0), 0.30 (T1), or 0.45 (T2) mg/L biotin in drinking water from 30 through 33 wk of age. The reproductive performance of the hens was evaluated using artificial insemination. At the end of the treatment period, 24 hens per line were killed to assay the expression of avidin and AVR2 in the uterovaginal junction. Supplementary biotin increased egg production from 73.5% for T0 to 87.8% for T2. Hens administered with biotin in line B, but not in line D, showed an increase (8.4%) in fertility rate. Hatchability, chick quality, and overall embryonic mortality were not different among the experimental groups. Real-time PCR data showed that both avidin (P=0.0013) and AVR2 (P<0.0001) expressions were influenced by a biotin×line interaction effect, where low-fertility line B hens receiving the high biotin level recorded respectively a 3.9 and 15.3% increase in avidin and AVR2 mRNA expression, although biotin did not affect these traits in line D hens. Control hens in line D had a dramatically higher AVR2 expression record (7.4-fold) compared with the control hens in line B. The correlation coefficients of fertility rate and avidin expression were 0.73 and 0.66 in lines B and D, respectively. However, the correlation of fertility and AVR2 (r=0.65) was significant for line D hens only. Overall, fertility rate and oviductal expression of avidin and AVR2 were dichotomously affected by oral biotin in low- and high-fertility line hens, where only low-fertility birds showed improvements in these attributes.
Topics: Administration, Oral; Animals; Avidin; Biotin; Chickens; Dietary Supplements; Egg Yolk; Female; Fertility; Gene Expression Regulation; Oviducts; RNA, Messenger; Vitamin B Complex
PubMed: 25630677
DOI: 10.3382/ps/peu073 -
Journal of Nanobiotechnology Jun 2022Protein-stabilized gold nanoclusters (Prot-Au NCs) have been widely used in biosensing and cell imaging owing to their excellent optical properties and low biotoxicity....
Protein-stabilized gold nanoclusters (Prot-Au NCs) have been widely used in biosensing and cell imaging owing to their excellent optical properties and low biotoxicity. However, several Prot-Au NCs reported in the literature do not retain the biological role of the protein, which greatly limits their ability to directly detect biomarkers. This study demonstrated for the first time the successful synthesis of dual-function avidin-stabilized gold nanoclusters (Av-Au NCs) using a one-pot method. The resulting Av-Au NCs exhibited intense blue and red emissions under 374 nm excitation. Furthermore, the Av-Au NCs retained the native functionality of avidin to bind to biotin. When DNA strands modified with biotin at both ends (i.e., linker chains) were mixed with Av-Au NCs, large polymers were formed, indicating that Av-Au NCs could achieve fluorescence signal amplification by interacting with biotin. Taking advantage of the aforementioned properties, we constructed a novel enzyme-free fluorescent biosensor based on the Av-Au NCs-biotin system to detect DNA. The designed fluorescent biosensor could detect target DNA down to 0.043 nM, with a wide line range from 0.2 nM to 20 µM. Thus, these dual-functional Av-Au NCs were shown to be an excellent fluorescent material for biosensing.
Topics: Avidin; Biosensing Techniques; Biotin; Coloring Agents; Gold; Metal Nanoparticles
PubMed: 35761380
DOI: 10.1186/s12951-022-01512-8 -
Biomolecules Apr 2022Intermittent jumping force is an operational atomic-force microscopy mode that produces simultaneous topography and tip-sample maximum-adhesion images based on force...
Intermittent jumping force is an operational atomic-force microscopy mode that produces simultaneous topography and tip-sample maximum-adhesion images based on force spectroscopy. In this work, the operation conditions have been implemented scanning in a repulsive regime and applying very low forces, thus avoiding unspecific tip-sample forces. Remarkably, adhesion images give only specific rupture events, becoming qualitative and quantitative molecular recognition maps obtained at reasonably fast rates, which is a great advantage compared to the force-volume modes. This procedure has been used to go further in discriminating between two similar protein molecules, avidin and streptavidin, in hybrid samples. The adhesion maps generated scanning with biotinylated probes showed features identified as avidin molecules, in the range of 40-80 pN; meanwhile, streptavidin molecules rendered 120-170 pN at the selected working conditions. The gathered results evidence that repulsive jumping force mode applying very small forces allows the identification of biomolecules through the specific rupture forces of the complexes and could serve to identify receptors on membranes or samples or be applied to design ultrasensitive detection technologies.
Topics: Avidin; Microscopy, Atomic Force; Streptavidin
PubMed: 35454182
DOI: 10.3390/biom12040594 -
BMC Structural Biology Sep 2009Avidins are proteins with extraordinarily high ligand-binding affinity, a property which is used in a wide array of life science applications. Even though useful for...
BACKGROUND
Avidins are proteins with extraordinarily high ligand-binding affinity, a property which is used in a wide array of life science applications. Even though useful for biotechnology and nanotechnology, the biological function of avidins is not fully understood. Here we structurally and functionally characterise a novel avidin named xenavidin, which is to our knowledge the first reported avidin from a frog.
RESULTS
Xenavidin was identified from an EST sequence database for Xenopus tropicalis and produced in insect cells using a baculovirus expression system. The recombinant xenavidin was found to be homotetrameric based on gel filtration analysis. Biacore sensor analysis, fluorescently labelled biotin and radioactive biotin were used to evaluate the biotin-binding properties of xenavidin - it binds biotin with high affinity though less tightly than do chicken avidin and bacterial streptavidin. X-ray crystallography revealed structural conservation around the ligand-binding site, while some of the loop regions have a unique design. The location of structural water molecules at the entrance and/or within the ligand-binding site may have a role in determining the characteristic biotin-binding properties of xenavidin.
CONCLUSION
The novel data reported here provide information about the biochemically and structurally important determinants of biotin binding. This information may facilitate the discovery of novel tools for biotechnology.
Topics: Amino Acid Sequence; Animals; Avidin; Binding Sites; Biotin; Crystallography, X-Ray; Ligands; Molecular Sequence Data; Protein Structure, Tertiary; Recombinant Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Xenopus
PubMed: 19788720
DOI: 10.1186/1472-6807-9-63