In nature we can find a variety of systems by which plants and animals are defending against dangers coming from their surrounding. The aim of this contribution is to show three different types of nanostructures, which are one, two or three dimensional and show their function in defence of nature objects. First type are nanoparticles. In specific types of plants, when they are growing they make primary nanoparticles which are made of silicon dioxide with a size from one till tens of nanometers. These structures then form a bigger globular formation. Moreover, these formations make up layers, which serve as a compact barrier against microorganisms. The second type of nanostructures has a prolonged shape with a diameter size of tens of nanometers and a length of hundreds of nanometers. It could be found on plant surfaces. These structures have wax characteristics which allow them to be superhydrophobic. From these kind of surfaces even dirt can be washed away, as well as pathogens which stick to drops of water. The third type of nanostructure is a three dimensional nanoformation in a conical shape, which can be found on the wings of cicada. The ratio of these formations are approximately 150 nanometers at the base and 30 nanometres at the top, with a height of 200 nanometers. These nanocones have the ability to disturb cell walls of bacteria which are sticking to it. The breaching of these cell walls is caused by physical-mechanical processes without the usage of chemical substances.
Nanofibers (NF) are often considered to be a suitable material for drug delivery, tissue engineering, and wound healing. Hyaluronic acid (HA) NF is a promising material for wound healing because of its biocompatibility and ability to stimulate the healing process. NF materials enable incorporation of various amounts of additives and their subsequent release during e.g. medical applications. The release of additives is related to NF layer material, type of additive and release environment.
NF layers made from HA derivative including an electrospinning-supporting polymer with potential application in wound healing were prepared. Furanyl HA derivative (HA-FU) was used due to its crosslinking ability resulted in e.g. lower solubility. Brilliant green (BG) as a model drug was chosen because of its detectability, antiseptic properties, and common usage as a topic bandage. Influence of NF layer crosslinking and addition of cover shell on BG release was evaluated. HA-FU NF layer with 2wt% of BG was prepared using 4SPIN® LAB. The BG release from both crosslinked and uncrosslinked samples was led into the phosphate buffer. As cover material NF layers without any additives were used. The concentration of BG in release environment was determined by means of UV-Vis spectroscopy.
The results exhibited as it was assumed that the drug release from HA-FU electrospun layers can be tune by crosslinking and/or adding the cover shell layer. The addition of cover layer resulted in disturbance of burst effect that was observed together with the effect of core crosslinking where the gel-blocking effect takes a role.
Cerium oxide nanoparticles were prepared by the hydrothermal method. Simultaneous measurements of the bovine serum albumin adsorption and zeta potential determination of the (adsorption) suspensions were carried out. The samples of nanoceria with positive zeta potential adsorbed more bovine serum albumin while on the other hand, the samples with negative zeta potential exhibited little or no protein adsorption. Particle size distribution and the influence of pH and temperature on the zeta potential of the prepared CeO2 and BSA were determined. The adsorption isotherms of BSA on CeO2 were found to be of the typical Langmuir type; values of the bovine serum albumin adsorption capacities were calculated. Increasing pH led to a decrease in zeta potential and decrease in the adsorption capacity of cerium oxide nanoparticles. It was proved that the adsorption capacity of BSA on nanoceria particles increased with a rise in temperature. The maximum adsorption capacity was found for an acid (pH 4) suspension and temperature of 34oC (am = 124 mg/g). Calculated thermodynamic parameters indicate that the adsorption of BSA on the ceria is an endothermic (ΔHads > 0) and spontaneous (ΔGads < 0) process. The kinetics of adsorption best fit the pseudo-second-order.
In this article we address with the antibacterial effect of nanocomposite thin films TiO2:SiO2:Ag on two Gram-negative bacteria Escherichia coli and Pseudomonas. putida. The thin films were deposited on glass substrates without heating by r.f. magnetron co-sputtering of TiO2 target with small plates of quartz and Ag on its surface in the zone with maximum erosion. The total area of quartz plates was 750 mm2 and the areas of Ag plates were 40 mm2 and 100 mm2. High resistant E.coli and sensitive P. putida with ability to form biofilm were chosen for the test. The antibacterial activity was established by three representative experimental methods, including classical Koch’s method, optical density measurements and dehydrogenase activity inhibition, respectively. Bacteria were cultivated on thin films in liquid nutrient medium for 24 h without agitation. Completely deactivation of the bacterial growth was observed between the 1st and the 4th hours from the beginning of the experiment. The destruction of the bacterial cells was registered by scanning electron microscope images. The created nanostructured thin films have potential for application in the field of nanomedicine as coating for different surfaces and devices. ACKNOWLEDGEMENTS: Sofia University Scientific Fund (project 80-10-12/12.04.2017) and Bulgarian National Scientific Fund (grand DCOST 01/14/08.12.2016) are gratefully acknowledged for the financial support of this investigation performed in the frame of COST Action TD 1305 "Improved Protection of Medical Devices Against Infections".
Vibrational spectroscopy (IR-absorption and Raman spectroscopy) allows for the labelfree detection of molecular specific fingerprints of inorganic, organic and biological substances. To reach detection levels required for an ultrasensitive analysis the sensitivity of vibrational spectroscopy can be improved by several orders of magnitude via the application of plasmonic active surfaces. Within this contribution, we will discuss two such approaches, namely surface enhanced Raman spectroscopy (SERS) as well as surface enhanced IR absorption (SEIRA). It will be shown that SERS using metal colloids as SERS active substrate in combination with a microfluidic lab-on-a-chip (LOC) device enables high throughput and reproducible measurements with highest sensitivity and specificity. The application of such a LOC-SERS approach for therapeutic drug monitoring (e.g. quantitative detection of antibiotics in a urine matrix) will be presented. Furthermore, we will introduce innovative bottom-up and top-down strategies to prepare SERS-active substrates like e.g. nanostructures coated with a lipophilic sensor layer as one-time use SERS substrates for specific food analysis (e.g. quantitative detection of toxic food colorants). The last part of this contribution presents a slit array metamaterial perfect absorber for IR sensing applications consisting of a dielectric layer sandwiched between two metallic layers of which the upper layer is perforated with a periodic array of slits. Light-matter interaction is greatly amplified in the slits, where also the analyte is concentrated, as the surface of the substrate is covered by a thin silica layer. Thus, already small concentrations of analytes down to a monolayer can be detected by refractive index sensing and identified by their spectral fingerprints with a standard mid-infrared lab spectrometer. ACKNOWLEDGEMENTS: Financial support of the EU, the ”Thüringer Ministerium für Wirtschaft, Wissenschaft und Digitale Gesellschaft”, the ”Thüringer Aufbaubank”, the Federal Ministry of Education and Research, Germany (BMBF), the German Science Foundation, the Fonds der Chemischen Industrie and the Carl-Zeiss Foundation are greatly acknowledged.
Aptamers, single-stranded nucleic acid molecules, have been widely used in disease diagnosis and bioassays since their first report1. Compared to traditional recognition element antibodies, the aptamers have many unique properties that make them more advantageous, including low cost and large scale production2. Thrombin, a serine protease, plays an important role in the coagulation cascade3. It can convert fibrinogen into fibrin monomer by activating the platelet, and then the fibrin monomer covers the cut and blocks the wound to stop bleeding. The abnormal levels of thrombin are closely related to human diseases such as thrombus, tumor or inflammation4.
In general, nanomaterials can be fitted with appropriate functional groups in order to tailor their physico-chemical as well as their structural and dimensional properties. In turn, such nano-engineered platforms might offer reproducible immobilization of bioreceptor units, enhanced sensitivity for given target or increased biocompability of these nanomaterials. In this work, we used hybrid of metal-organic gel combined with fluorinated graphene oxide as sensing platform for thrombin detection using thrombin-binding aptamer. In this case, combination of large internal surface and hierarchical pores of hybrids offer great sensitivity for target detection.
REFERENCES: [1] Ellington, A. D.; Szostak, J. W.; Nature 1990, 346, 818-822.; [2] Hermann, T.; Patel, D. J.; Science 2000, 287, 820-825.; [3] Ariens, R. A.; Philippou, H.; Nagaswami, C. ; Weisel, J. W. ; Lane, D. A.; Grant, P. J. ; Blood 2000, 96, 988-995.; [4] Martinelli, R. A.; Scheraga, H. A.; Biochemistry 1980, 19, 2343-2350.
Carbosilane dendrimers (CS-Dms) represent three-dimensional branched molecules with defined structure and accurate molar weight. As they have favorable properties like high density of peripheral groups, hydrophobic core, low cytotoxicity and high biocompatibility, CS-Dms are under intensive investigation for many biomedicinal applications, mainly for drug targeting and gene therapies.
CS-Dms with cationic groups at their periphery are able to form complexes (dendriplexes) with antisense oligonucleotides and interact with cellular structures. Progress in the field of gene therapies depends on the development of specific, non-toxic and effective vectors for therapeutic delivery of nucleic acids. For that purpose, CS-Dms mainly with ammonium groups were investigated1. CS-Dms bearing other cationic groups attracted only little attention so far.
The study is focused on synthesis and chemical properties of new library of CS-Dms with phosphonium groups on the periphery. As we previously reported on methyl- substituted CS-Dms differing only in onium group (N or P), substitution of nitrogen atom by phosphorus improves overall cytotoxicity. To evaluate the effect of substitution on phosphorus atom we prepared four series of CS-Dms decorated with phosphonium groups with both aliphatic and aromatic substituents attached to P atom. Comparative study of their cytotoxicity, the ability to form dendriplexes and their transfection through cell membrane will be presented2.
ACKNOWLEDGEMENTS: The authors thank Czech Science Foundation (GA CR) (GA15-05903S) for financial support.
REFERENCES: [1] Arnáiz, E.; Doucede, L. I.; García-Gallego, S.; Urbiola, K.; Gómez, R.; Tros de Ilarduya, C.; de la Mata, F. J. Mol. Pharmaceutics 2011, 9, 433−447.; [2] Strasak, T., Malý, J., Wróbel, D., Malý, M., Herma, R., Čermák, J., Müllerová, M., Červenková Šťastná, L., Cuřínová, P. RSC Advances, 2017, 7, 18724 – 18744.
The microRNA(miRNA)-34a is an important regulator of tumor suppression. It controls the expression of several target proteins involved in cell cycle, differentiation and apoptosis, and antagonizes processes that are necessary for basic cancer cell viability as well as cancer stemness, metastasis, and chemoresistance. It is downregulated in numerous cancer types, including prostatic cancer, and inhibits malignant growth by repressing genes involved in various oncogenic signaling pathways. Given the anti-oncogenic activity of miR-34a, here we proved the substantial benefits of a new therapeutic concept based on nanotechnology delivery of miRNA mimics. In order to monitor the miRNA-34a replacement, we used a fluorescent nanodiamond particles (FND) system with linked miRNA-34a mimic, which was delivered to PC3 and DU145 prostatic cancer cell lines. We used functionalized nanodiamonds coated with polyethylenimine to transfer miRNA-34a into PC3 and DU145 prostatic cancer cell lines and we measured the zeta-potential of these complexes before using them for in vitro experiments. A replacement of miRNA-34 was observed by monitoring levels of miRNA-34 via real-time PCR. Moreover, our in vitro experiments demonstrated that miRNA-34a replacement, using this FND delivery system, decreased viability and induced apoptosis in prostatic cancer cell lines. Our findings suggest the replacement of oncosuppressor miRNA-34a provides an effective strategy for cancer therapy and the FND-based delivery systems seems to be an excellent strategy for a safe and effective targeting of the tumor.The project was supported by the Ministry ofEducation, Youth and Sports of the Czech Republic under NPU: LO1309 and LO1508 and by Ministry of Health of the Czech Republic, grant number 15-33094A.
Endodontic treatment of permanent immature tooth with necrotic pulp poses several clinical challenges and is generally considered to be one of the most demanding intervention in endodontics. In a recent time with new findings in the field of tissue engineering has been established new treatment protocols. The most spread treatment modality is revascularization, based on an exposure of collagen matrix and embedded growth factors.
In this work, Surface enhanced Raman spectroscopy (SERS) was utilized to screen the influence of protocol parameters, namely time of treatment using EDTA, on an exposure and accessibility of growth factors, including TGF- β1, BMP-2 and bFGF on a dentin surface. The nanotags, consisted of noble-metal nanoparticles applicable in SERS, covalently functionalized using Raman labels (Cy3, Cy5, Cy7) and respective antibodies (anti-TGF-β1, anti-BMP-2 and anti-bFGF), were employed as a SERS substrate. Each antibody was coupled with a different label to allow a multiplexed analysis of all three labels in one analytical run. Performed analysis showed an increasing amount of exposed growth factors with longer times.
Nanomedicine is the field of research with huge expectations for the development of personalized medicine based on the application of nanoparticles as nanoscale materials interact effectively with biological systems. Therefore, the use of nanodiagnostics in vivo imaging and nanotherapeutics for use in drug delivery may allow overcoming many intractable health challenges. The term “theranostic” is defined as a material that combines the modalities of therapy and diagnostic imaging. Thus, theranostics deliver therapeutic drugs and diagnostic imaging agents at the same time within one dose.
In the presented work, we were focused on developing a new strategy for the preparation of the theranostic nanocarriers (TNCs). The TNCs were composed of biopolymer (polycaprolactone, PCL) and iron oxide nanoparticles (Fe3O4 or Fe2O3) incorporated into solid core as well as polyelectrolyte shell. The nanocarriers’ shell was prepared using Layer-by-Layer technique based on sequential adsorption of biocompatible polyelectrolytes (poly L-lysine, PLL and poly-glutamic acid, PGA) and iron oxide nanoparticles. All synthesized TNCs were characterized by size, size distribution and zeta potential measurements using Zetasizer Nano ZS (Malvern Instruments). Using preclinical MRI scanner we demonstrated that incorporation of magnetic nanoparticles in polyelectrolyte multilayer shell allowed obtaining nanocapsules sensitive to a magnetic field, which thus can be detected due to locally altered contrast in the MR image. Obtained results indicate that our nanocarriers are a promising platform for future theranostic application.
ACKNOWLEDGEMENTS: This work was supported by grants from the Polish National Science Centre, grant UMO-2015/17/B/ST5/02808, and grant PRELUDIUM 2016/23/N/ST5/02783.
Synthesis of theranostic nanoparticles or nanocapsules, which combine both therapeutic and diagnostic capabilities in one platform, is the first step forward personalized medicine. The layer-by-layer adsorption of polyelectrolytes is considered as a convenient method to obtain multilayer nanocapsules’ shells on colloidal cores. A polyelectrolyte shell of capsules can be functionalized e.g. by immobilization of targeting ligands or nanoparticles to form theranostic carriers. The aim of this work was to develop the method of preparation of theranostic nanocapsules containing Gadolinium contrast agent. The nanocapsules were prepared by sequential adsorption of polyelectrolytes (layer by layer technique) using biocompatible polyelectrolytes (Poly L-lysine and Gadolinium-Labeled Polylysine as the polycations, Poly-Glutamic acid as the polyanion). Formation of the hybrid multilayer polyelectrolyte shell was evidenced by zeta potential changes with number of layer. The PEG corona grafted on the top polyelectrolyte layer assured stability of nanocapsules against aggregation in the media with high ionic strength (FBS solution). We demonstrated that incorporation of Gadolinium labeled polyelectrolyte into polyelectrolyte multilayer shell allowed obtaining nanocapsules, which can be imaged by MRI. They may be a promising platform for future targeted therapies (e.g. cancer) or other biomedical applications (e.g. diagnostics).
After decades of intensive nanoresearch, nanoparticles are widely implemented as functional elements on surfaces, into volumes and as nanohybrids, with a wide spectrum of applications such as catalysis and biomedicine. However, integration of the “nanofunction” into products is still limited due to drawbacks of gas phase and chemical synthesis methods regarding particle aggregation and contaminantion with artificial additives causing deactivation of the building blocks´surface.
As an alternative synthesis route, nanoparticle generation by lasers in liquids has proven its capability to generate totally ligand-free colloidal nanoparticle building blocks1, which are already commercially available. Recent studies highlight unique properties of laser-generated nanoparticles potentially integrated into real-world applications in biology and medicine1. One approach in nanointegration of laser-generated nanoparticles involves nanocomposites, which can be fabricated in situ by laser ablation synthesis, directly in monomer or polymer solutions, yielding enhanced matrix coupling and outstanding composite stability even after thermal post processing. The laser-fabricated nanocomposites were shown to favour cell proliferation and migration, which makes them particularly suitable as advanced implant materials2, 3. Scale-up of the laser-based synthesis route is demonstrated4 fabricating kilogram scale of polymer membrane nanocomposites essential in artificial lung implants. Another field of great interest are surface coatings on metal implants, e.g. electrode surfaces modified by electrophoretic deposition5. First in vivo studies on neural electrodes modified by ligand.free platinum nanoparticles show application prospects in treatment of Parkinson deasease6. Nanoparticles from laser-based synthesis are also applicable in the colloidal state, where they may be utilized in toxicity studies7 as well as for bioimaging. In this context solid solution gold-silver alloy nanoparticles were applied in reference material series, which represent a grayscale of toxicity, used to model unintended implant debris toxicity using a very sensitive biofunctional system: mammalian reproduction biology8. The studies involve life cell imaging and intracellular quantification of single, 60 femtogram plasmonic nanoobjects. Finally, laser-synthesized nanoparticles can also be conjugated with functional biomolecules forming nanobioconjugates, where their additive-free naked surface allows an extemely efficient conjugation process with a high surface coverage9. Specifically designed gold nanoparticle-peptide-conjugates were demonstrated to be highly efficient in the decomposition of protein aggregates and oligomers, believed to be involved in the pathology of neurodegenerative diseases such as Alzheimer´s disease10.
REFERENCES: [1] D. Zhang, B. Gökce and S. Barcikowski, Chemical Reviews, 2017.; [2] A. Blaeser, N. Million, D. F. D. Campos, L. Gamrad, M. Kopf, C. Rehbock, M. Nachev, B. Sures, S. Barcikowski and H. Fischer, Nano Res., 2016, 9, 3407-3427.; [3] C. Hess, A. Schwenke, P. Wagener, S. Franzka, C. L. Sajti, M. Pflaum, B. Wiegmann, A. Haverich and S. Barcikowski, J. Biomed. Mater. Res. Part A, 2014, 102, 1909-1920.; [4] R. Streubel, S. Barcikowski and B. Gokce, Opt. Lett., 2016, 41, 1486-1489.; [5] S. Koenen, R. Streubel, J. Jakobi, K. Schwabe, J. K. Krauss and S. Barcikowski, Journal of the Electrochemical Society, 2015, 162, D174-D179.; [6] S. D. Angelov, S. Koenen, J. Jakobi, H. E. Heissler, M. Alam, K. Schwabe, S. Barcikowski and J. K. Krauss, Journal of Nanobiotechnology, 2016, 14.; [7] U. Taylor, A. Barchanski, S. Petersen, W. A. Kues, U. Baulain, L. Gamrad, L. Sajti, S. Barcikowski and D. Rath, Nanotoxicology, 2014; [8] D. Tiedemann, U. Taylor, C. Rehbock, J. Jakobi, S. Klein, W. A. Kues, S. Barcikowski and D. Rath, Analyst, 2014, 139, 931-942.; [9] S. Petersen and S. Barcikowski, Journal of Physical Chemistry C, 2009, 113, 19830-19835.; [10] C. Streich, L. Akkari, C. Decker, J. Bormann, C. Rehbock, A. Muller-Schiffmann, F. C. Niemeyer, L. Nagel-Steger, D. Willbold, B. Sacca, C. Korth, T. Schrader and S. Barcikowski, Acs Nano, 2016, 10, 7582-7597.
The easy and fast detection of drug content and concentration levels is demanded in biological research as well as in clinical practice. Therefore, label-free platforms based on photonic, mechanical, electrochemical or electrical detection principles are being intensively developed. Nanomaterials and structures are often introduced to provide a fast and sensitive response. Gold and nanodiamond particles exhibit unique features for such applications. To understand the nanoparticle functions and their impact on overall sensor response, detailed characterization of interactions between molecules and nanoparticles is essential.
Here we explore structural and chemical interactions of gold and nanodiamond particles with a drug (EN-142), linker (MTAB: 16-merkaptohexadecyltrimethylamoniumbromid) and solvents (water, MeOH, DMSO) being developed for treatment of Alzheimer disease. We use detonation nanodiamonds with hydrogen rich (as-received H-DNDs) and annealed oxidized surfaces (O-DNDs) as well as gold nanoparticles (20 nm, citrate stabilized) in aqueous colloidal suspensions. We apply Fourier-transform infrared spectroscopy in ATR arrangement and corroborate the data with atomic force microscopy. We compare the results before and after rinsing of the composite and reference (single component) samples with water and/or MeOH. The results show that: 1) all components (nanoparticles, linker, drug) can be resolved via specific IR spectral features; 2) MTAB linker binds and interacts with Au nanoparticles in solution as well as on substrate while citrate signal is quenched; 3) the drug binds both to gold and to diamond nanoparticles (with or without Au nanoparticles and MTAB); 4) the drug is removed from H-DND and MTAB functionalized Au by MeOH, yet it remains stable in water; 5) the drug binds stably to O-DND even after MeOH rinsing. The IR spectra after the MeOH rinsing indicate less pronounced drug vibrations on O-DNDs, due to stronger binding and/or lower drug amount. Nanodiamonds thus provide perspective binding platform for the drug detection.
We discuss role of zeta potential, molecular charge and surface functional groups on the binding and rinsing effects. We also discuss impact of the results for application in biosensors. The work has been financially supported by GACR 17-19968S.
Photon-upconversion nanoparticles (UCNPs) have become an attractive label in immunoassays because their anti-Stokes luminescence can be excited by the NIR laser and detected in the VIS region without optical background interference. Further advantages of UCNPs include good photostability, large anti-Stokes shifts, and multiple and narrow emission bands that can be used for multiplexed detection.
We have developed a competitive upconversion-linked immunoassay (ULISA) for the detection of the pharmaceutical diclofenac (DCF) in surface waters. Silica-coated UCNPs with carboxyl groups on the surface were synthesized and conjugated with secondary anti-IgG antibody. The structure and monodispersity of the nanoconjugates was studied in detail by TEM and agarose gel electrophoresis [1]. Using a highly affine anti-DCF primary antibody, the optimized ULISA provided a detection limit of 50 pg/mL [2].
Due to the low background, single UCNPs can be visualized by a simple wide-field optical microscopy under 980 nm excitation. Prostate specific antigen (PSA) was used as a model analyte with a high clinical relevance to establish a single molecule sandwich ULISA. A microtiter plate was coated with anti-PSA antibodies and UCNPs (48 nm in diameter) were conjugated to anti-PSA antibody as a detection label. Counting individual UCNPs (digital readout) was used to determine the PSA concentration. The digital readout of PSA had a detection limit of 1.2 pg/mL of PSA in 25% serum and was more sensitive than a conventional microtiter plate reader (analog) detection [3]. REFERENCES: [1] Hlaváček A, Sedlmeier A, Skládal P, Gorris HH. ACS Appl. Mater. Interfaces. 2014, 6, 6930–6935.; [2] Hlaváček A, Farka Z, Hübner M, Horňáková V, Němeček D, Niessner R, Skládal P, Knopp D, Gorris HH. Anal. Chem. 2016, 88, 6011-6017.; [3] Farka Z, Mickert MJ, Hlaváček A, Skládal P, Gorris HH. 2017, submitted.
Classical “wet“ chemistry methods can produce polymers with well‑defined molecular structure, but many types of polymers are hard to prepare with significant degree of crosslinking without residues of the crosslinking agent. On the other hand, plasma polymers usually have very high degree of crosslinking but nearly random molecular structure.
Plasma‑assisted vapour thermal deposition combines both methods. Classical polymers are heated in a crucible at low pressure and the released oligomeric fragments of the polymer chain are repolymerized in a glow discharge into a thin film. The number of well‑preserved monomeric units between the crosslinks can be tuned e.g. from units to tens.
Special class of of polymeric materials are biodegradable polymers like poly-lactic acid (PLA) or poly-ethylene oxide (PEO). In this work, plasma polymers prepared from various PLA and PEO precursors are presented. Molar weights and chemical composition of the “precursor” polymer and of the thin films have been characterized. As the measure of degradability, behaviour of the polymers during hydrolysis has been studied using spectroscopic ellipsometry and liquid chromatography. Possibility to prepare plasma polymer films with controlled degradability was demonstrated. ACKNOWLEDGEMENTS: This work was supported by the grant 17‑10813S of the Czech Science Foundation.
The use of proteins and enzymes for therapeutic purposes requires the maintenance of sufficient activity during in vivo treatment. Many proteins exhibit short half-life in vivo and therefore require carrier structures to selectively transport them to diseased cells or tissues. The biocompatibility and ability to create functionalized bioconjugates make gold nanoparticles (AuNPs) the perfect candidate for the creation of such structures [1]. Immobilization on the nanomaterial surface should not cause a decrease in protein / enzyme activity by blocking access to the active center. It is necessary to spatially position the biomolecules on the AuNPs surface.
The work presents a comparison of the antioxidant activity of catalase immobilized on AuNPs surface by two methods. The first involves protein adsorption directly on the nanoparticles surface. The second is based on the chemical bonding of the enzyme, through the specific binding between the imidazole histidine groups of His-tag-catalase and Ni2+ ion, complexed by the nitrilotriacetic acid residue present on the surface of AuNPs (NTA-linker). The use of NTA-linker makes it possible to immobilize catalase on nanoparticles without losing its enzymatic activity. ACKNOWLEDGEMENTS: Scientific work supported by National Science Centre of Poland project number 2013/09/B/NZ7/01019 and by University of Lodz, Subsidy for scientific research contributing to the development of young researchers and PhD students, project number: B1711100001603.02. REFERENCE: 1. Ranoszek-Soliwoda K., Czechowska E., Tomaszewska E., Celichowski G Kowalczyk T.,Sakowicz T., Szemraj J., Grobelny J. Catalase-Modified Gold Nanoparticles: Determination of the Degree of Protein Adsorption by Gel Electrophoresis // Colloids and Surface B:-2017 - accepted.
Non-healing wounds are serious complication in diabetic patients and represent a challenge for development of biocompatible carrier system possessing slow and driven biomolecule release. Electrospun nanofibers are suitable material for wounds dressing. Fluorescent nanodiamond particles (FND) have been previously shown to be an efficient biocompatible RNA delivery system enabling real-time imaging of carried payload.
Here we used FNDs carrying small interfering RNA (siRNA) via a pH-sensitive polymer linker that are embedded into the cores of PCL/PVA nanofibers. The siRNA specifically targets matrix metalloproteinases (MMPs) since their overexpression is a major cause of healing failure in diabetic wounds.
We incorporated FND-siRNA complexes into core/shell nanofibers, visualized the nanosystem by confocal microscopy and used electron microscopy for the characterization. Real-time PCR was used to assess the silencing effect of siRNA that has been delivered to target murine fibroblasts by FND released from nanofibre dressing. Nanofibrous system with embedded FNDs was applied on wounds in diabetic animal models to show its suitability regarding short and long term toxicity, efficacy, and handling in vivo.
In summary we developed driven and biocompatible RNA delivery system enabling localized and effective gene therapy of diabetic non-healing wounds.