• Home
  • Radostina Georgieva
Radostina Georgieva

Radostina Georgieva
Trakia University Stara Zagora

Professor

About

72
Publications
11,788
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,177
Citations
Citations since 2016
28 Research Items
1002 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Additional affiliations
July 2009 - December 2018
Trakia University, Stara Zagora, Bulgaria
Position
  • Professor (Full)
January 2006 - August 2022
Charité Universitätsmedizin Berlin
Position
  • Senior Researcher
January 2005 - December 2006

Publications

Publications (72)
Article
Full-text available
The co-localization of platelets and tumor cells in hematogenous metastases has long been recognized. Interactions between platelets and circulating tumor cells (CTCs) contribute to tumor cell survival and migration via the vasculature into other tissues. Taking advantage of the interactions between platelets and tumor cells, two schemes, direct an...
Article
This paper describes the synthesis and O2 binding properties of core-shell structured hemoglobin (Hb) nanoparticles (NPs), artificial O2 carriers of five types, as designed for use as red blood cell (RBC) substitutes. Human adult Hbs were polymerized using α-succinimidyl-ω-maleimide and dithiothreitol in spheroidal shapes to create parent particles...
Chapter
Hemoglobin-based oxygen carriers (HBOC) have been the subject of scientific studies for decades. The fabrication of HBOC is sophisticated, but meanwhile also simpler nano- and microparticle fabrication methods exist. One of them consists of three key steps: Co-precipitation of insoluble metal carbonates with biopolymers, Cross-linking of co-precipi...
Article
Full-text available
Hemoglobin microparticles (HbMP) produced with a three-step procedure, including coprecipitation of hemoglobin with manganese carbonate, protein cross-linking, and dissolution of the carbonate template were shown to be suitable for application as artificial oxygen carriers. First preclinical safety investigations delivered promising results. Bacter...
Preprint
Full-text available
Hemoglobin microparticles (HbMP) produced with a three-step procedure including co-precipitation of hemoglobin with manganese carbonate, protein crosslinking and dissolution of the carbonate template were shown to be suitable for application as artificial oxygen carriers. First preclinical safety investigations delivered promising results. Bacteria...
Article
Full-text available
In this study, we describe a nano-carrier system for propolis that is able to cross an in vitro model of the blood-brain barrier (BBB) and effectively reduce the virulence of Cryptococcus neoformans in animal models. Antimicrobial properties of propolis have been widely studied. However, propolis applications are limited by its low water solubility...
Conference Paper
The redox reaction of hemoglobin (Hb) is studied by spectroelectrochemistry. Fifteen absorption spectra are measured at different electrode potentials in the range from +0.4 V to -0.3 V. The spectra are collected in a matrix, X, with each spectrum representing one column. The method of Principal component analysis (PCA) is applied by the aid of the...
Article
Full-text available
Non-sericin (NS) extract was produced from the ethanolic extract of Bombyx mori silk cocoons. This extract is composed of both carotenoids and flavonoids. Many of these compounds are composed of substances of poor aqueous solubility. Thus, this study focused on the development of a carrier system created from biocompatible and biodegradable materia...
Article
Full-text available
Methemoglobin (MetHb) is a hemoglobin (Hb) derivative with the heme iron in ferric state (Fe3+), unable to deliver oxygen. Quantification of methemoglobin is a very important diagnostic parameter in hypoxia. Recently, novel hemoglobin microparticles (Hb-MP) with a narrow size distribution around 700 nm, consisting of cross-linked Hb were proposed a...
Article
Full-text available
Doxorubicin (DOX) is an effective anthracycline antibiotic drug which is commonly used in a broad range cancer therapy. However, due to dose depending side effects and toxicity to non-cancerous tissues, its clinical applications are restricted. To overcome these limitations, human serum albumin (HSA) has been investigated as a biocompatible drug de...
Article
Full-text available
Riboflavin (RF) is a water-soluble member of the B-vitamin family. Sufficient dietary and supplemental RF intake appears to have a protective effect on various medical conditions such as sepsis, ischemia etc., while it also contributes to the reduction in the risk of some forms of cancer in humans. These biological effects of RF have been widely st...
Article
Full-text available
Blood compatibility is a key requirement to fulfil for intravenous administration of drug and oxygen carrier system. Recently, we published the fabrication of oxidised-dextran (Odex)-crosslinked protein particles by one-pot formulation. In the current study we investigate the haemocompatibility of these Odex - particles including albumin particles...
Article
Full-text available
CD33 is a myeloid-associated marker and belongs to the sialic acid-binding immunoglobulin (Ig)-like lectin (Siglec) family. Such types of receptors are highly expressed in acute myeloid leukemia, which could be used in its treatment. CD33 shows high variability in its expression levels with still unknown reasons. Here, we investigated the CD33 expr...
Article
Full-text available
Hemoglobin-based oxygen carriers (HBOCs) represent a propitious type of blood substitute to transport oxygen throughout the body while acting as a carrier in biomedical applications. However, HBOCs in blood are recognized and rapidly scavenged by the body’s innate immune systems. To overcome this problem, HBOCs require a surface modification that p...
Article
Full-text available
Although riboflavin (RF) belongs to the water-soluble vitamins of group B, its solubility is low. Therefore, the application of micro-formulations may help to overcome this limiting factor for the delivery of RF. In this study we immobilized RF in newly developed albumin submicron particles prepared using the Co-precipitation Crosslinking Dissoluti...
Article
Full-text available
The effects of thioridazine (TDZ) and chlorpromazine (CPZ) and bovine serum albumin nanoparticles (BSA-NPs) on erythrocyte membranes have been investigated. Two kinds of hemolytic assays were used; hemolysis under hypotonic conditions and hemolysis in physiological conditions. Under hypotonic conditions for 50% hemolysis, both TDZ and CPZ have a bi...
Article
Clinically applicable haemoglobin-based oxygen carriers (HBOCs) should neither induce immunological nor toxic reactions. Additionally, Hb should be protected against oxidation. In the absence of protective enzymes (superoxide dismutase (SOD) and catalase (CAT)) Hb is oxidized to MetHb and thus losing its function of oxygen delivery. Alternatively,...
Article
Full-text available
The coprecipitation–cross-linking–dissolution (CCD) technique for protein submicron particle fabrication was improved by omitting one preparation step using the macromolecular cross-linker, periodate-oxidized dextran (Odex, M.W. of 40 and 70 kDa). The coprecipitation and cross-linking of haemoglobin (Hb) were combined in one single step since the c...
Article
The nanomaterials have been extensively applied in biomedical field. These nanoscale objects may either promote or restrain immune responses depending on their surface characteristics and compositions. In this study, chitosan (CS) particles prepared by an emulsion-crosslinking method were modified with different amounts of human serum albumin (HSA)...
Article
Hemoglobin-based oxygen carriers (HBOCs) are being developed as oxygen and plasma volume-expanding therapeutics though their potential to promote oxidative tissue injury and nitric oxide (NO) scavenging combined with vasoconstriction has raised safety concerns. Therefore, we focused on these aspects during preclinical studies performed with the rec...
Article
The Co-precipitation Crosslinking Dissolution technique (CCD-technique) allows a few-steps fabrication of particles composed of different biopolymers and bioactive agents under mild conditions. Morphology and properties of the fabricated biopolymer particles depend on the fabrication conditions, the nature of the biopolymers and additives, but also...
Article
Full-text available
Stimuli-responsive particles are widely used as carriers for on-demand delivery of drugs, genes, proteins, etc., due to their response to environmental stimuli. In this study, photoresponsive albumin sub-micrometer particles are fabricated by using ortho-nitrobenzyl derivative 4-bromomethyl-3-nitrobenzoic acid (BNBA) as a cross-linker. Bovine serum...
Article
Full-text available
In this study we heated insoluble residues, obtained after Triton-X-100 (0.1 v/v%) extraction of erythrocyte ghost membranes (EGMs). Specific heat capacity, electric capacitance and resistance, and optical transmittance (280 nm) sustained sharp changes at 49°C (TA) and 66°C (TC), the known denaturation temperatures of spectrin and band 3, respectiv...
Article
The impact of macromolecules on RBC aggregation continues to be of interest, nevertheless present measurements still have limitations and need improvement. We applied flow cytometry to measure RBC aggregation in dextran T500 (Dx500) solution. The samples were fixed in the aggregated state by glutaraldehyde. Fixed RBC exhibit auto fluorescence, whic...
Article
Increasing antimicrobial resistance requires the development of novel materials and approaches for treatment of various infections. Utilization of photodynamic therapy represents an advanced alternative to antibiotics and metal-based agents. Here, we report the fabrication of electrospun material that possesses benefits of both topical antimicrobia...
Article
An analytical centrifugation technique (LUMiFuge) for mechanical testing is introduced. Measurements on calibrated springs with LUMiFuge and BOSE LM1-ElectroForce TestBench delivered similar values for E-moduli and spring constants. Native cylindrical scaffolds from cancellous femoral bone were successfully tested using this new technique. The E-mo...
Article
Novel chitosan-based nanofibrous composite materials containing different amounts of the photosensitizer Photosens were obtained by electrospinning and were characterized by scanning electron microscopy and by confocal laser scanning microscopy. The release of Photosens from the materials was investigated in water and in phosphate-buffered saline....
Article
The adsorption of proteins on surfaces often results in a change of their structural behavior and consequently, a loss of bioactivity. One experimental method to study interactions on a molecular level is single molecular force spectroscopy that permits to measure forces down to the pico-newton range. In this work, the binding force between human s...
Article
Polyelectrolyte microcapsules (PEMC) have a great potential for targeted delivery of drugs. PEMCs prepared on fixes erythrocytes were loaded with the water insoluble antifungal drug funphotericin B (AmB) by solvent exchange. The surface of loaded capsules was modified with polyethylene glycol to prevent from immune responses. The interaction of loa...
Article
During the last 30 years, artificial oxygen carriers have been investigated intensively with the aim to develop universal blood substitutes. Favorably, hemoglobin-based oxygen carriers (HBOCs) are expected to meet the sophisticated requirements. However, the HBOCs tested until now show serious side effects, which resulted in failure of clinical tri...
Article
5-Fluorouracil (5-FU) is a clinically well-established anti-cancer drug effectively applied in chemotherapy, mainly for the treatment of breast and colorectal cancer. Substantial disadvantages are adverse effects, arising from serious damage of healthy tissues, and shortcoming pharmacokinetics due to its low molecular weight. A promising approach f...
Article
In the present work the immobilization of enzymes within poly-N-Isopropylacrylamide (p-NIPAM) microgels using the method of solvent exchange is applied to the enzyme horseradish peroxidase (HRP). By changing the solvent from water to isopropanol HRP is embedded within the polymer structure. After determination of the immobilized amount of enzyme, a...
Article
Artificial oxygen carriers, favorably hemoglobin-based oxygen carriers (HBOCs) are being investigated intensively during the last 30 years with the aim to develop an universal blood substitute. However, serious side effects mainly caused by vasoconstriction triggered by nitric oxide (NO) scavenging due to penetration of nano-sized HBOCs through the...
Article
Bovine hemoglobin microparticles (Hb-MPs) as suitable oxygen carriers are fabricated easily by three key steps: coprecipitation of Hb and CaCO(3) to make Hb-CaCO(3)-microparticles (Hb-CaCO(3)-MPs), cross-linking by glutaraldehyde (GA) to polymerize the Hb and dissolution of CaCO(3) template to obtain pure Hb-MPs. The Hb entrapment efficiency ranged...
Article
The immobilization of lipase B from Candida antarctica (CalB) within micronsized poly-N-Isopropylacrylamide (p-NIPAM) microgel particles with a crosslinker content of 5% is reported. The immobilization of the enzyme was reached by an exchange from polar to organic solvents. After determining the embedded amount of CalB within the polymer network, a...
Article
The aim of the present work is the use of a water soluble enzyme in an organic solvent, still with a pronounced catalytic activity. Therefore, lipase B from Candida antarctica (CalB) is immobilized within micron-sized thermosensitive p-NIPAM hydrogel particles using a solvent exchange from polar to organic solvents. The absorbed amount of CalB is i...
Article
A nanoplasmonics-based opto-nanoporation method of creating nanopores upon laser illumination is applied for inducing diffusion and triggered release of small and large molecules from red blood cells (RBCs). The method is implemented using absorbing gold nanoparticle (Au-NP) aggregates on the membrane of loaded RBCs, which, upon near-IR laser light...
Article
Full-text available
Red blood cells (RBCs) are natural carriers which can be used for targeted drug delivery. Conditions during loading and surface modification are essential for carrier-RBC preparation for specifically targeted drug delivery. Therefore, human RBCs were loaded with albumin and magnetic nanoparticles (NPs) by different hypotonic haemolysis procedures a...
Article
In this article, a non-chemical crosslinking method is used to produce pure protein microparticles with an innovative approach, so-called protein activation spontaneous and self-assembly (PASS). The fabrication of protein microparticles is based on the idea of using the internal disulfide bridges within protein molecules as molecular linkers to ass...
Article
Full-text available
The objective of this study was to investigate the effect of new 4-maleamic acid and 4-maleamide peptidyl chalcone derivatives against human prostate cancer in vitro and in vivo. From a series of 21 chalcones, the effects of the three best inhibitors of PC-3 and LNCaP cell viability on growth, including cell cycle changes, adhesion, migration, and...
Article
Transfer of a fluorescently labeled protein particle from a surface to a microsized scanning probe has been induced by repetitive scanning in aqueous medium. The so-attached particle can in turn act as a probing tool to study particle-substrate and particle-particle interactions. Attachment of the fluorescent particle occurs at the apical region of...
Article
Spherical biopolymer particles have been fabricated, applying coprecipitation with calcium carbonate, followed by cross-linking of the macromolecules and dissolution of the inorganic support. Particles made of roughly 80% horseradish peroxidase (HRP) as well as glucose oxidase (GOX) were prepared and enzyme activities were confirmed, applying the A...
Article
Full-text available
The present work describes the synthesis, physico-chemical and biological properties of the first water-soluble goethite nanoparticles covered with biologically active components: oleic acid and cytotoxic decyldimethyl(dimethylaminoethoxy)silane methiodide. The structure of initial goethite nanoparticles synthesized was proved by XRD analysis and t...
Article
The efficacy of antifungal treatment has been diminished by the biodistribution limitations of amphotericin B (AmB) due to its pharmacological profile, as well as the severe side effects it causes. A cellular drug-delivery system, which incorporates human erythrocytes (RBCs) loaded with an AmB nanosuspension (AmB-NS), is developed in order to impro...
Article
Full-text available
A number of catechol-terminated copolymers of di(ethylene glycol) methyl ether methacrylate (MEO2MA) and poly(ethylene glycol) methyl ether methacrylate (OEGMA) with varied MEO2MA-to-OEGMA molar ratios were synthesized via atom transfer radical polymerization triggered by dopamine-derived initiators. They were grafted on magnetite nanoparticles (NP...
Patent
Full-text available
The invention concerns microparticles with modified or unmodified surfaces that contain at least one aggregate composed of superparamagnetic nanoparticles; the nanoparticles can be in combination with a drug whereby the drug is bound or not bound to the nanoparticles. The microparticles further include human or animal cells, liposomes, polyelectrol...
Article
Polyelectrolyte microcapsules composed by using the LbL technique on stabilized RBC as templates were coated with up to ten layer pairs of trypsin/PSS or trypsin/alginate. The trypsin layer growth was confirmed by particle electrophoresis, confocal laser scanning microscopy, flow cytometry, and protein determination according to Lowry. In the coati...
Article
Full-text available
This study presents evidence for the role of spectrin and the anion exchanger in the temperature activation of ion permeability, hyperthermic permeability transition (HPT), involved in thermal necrosis of RBCs. Membranes, undergoing HTP at conditions sparing the structure of spectrin (39 degrees C, 18%, v/v ethanol, 3 min), became irreversibly perm...
Article
Superparamagnetic iron oxide nanoparticles (SPIONs) are commonly used in magnetic resonance imaging (MRI), but their fast phagocytosis makes them less than ideal for this application. To circumvent the lymphocyte-macrophage system, we encapsulated SPIONs into red blood cells (RBCs). For loading, the RBC's membrane was opened by swelling under hypoo...
Article
A novel method for the encapsulation of biomacromolecules, such as nucleic acids and proteins, into polyelectrolyte microcapsules is described. Fluorescence-labelled double-stranded DNA and human serum albumin (HSA) are used as model substances for encapsulation in hollow microcapsules templated on human erythrocytes. The encapsulation procedure in...
Article
Full-text available
Polyelectrolyte capsules of poly( styrene sulfonate, sodium salt) and poly( allylamine hydrochloride) prepared on weakly polymerized melamine formaldehyde colloidal particles have been incubated in solutions of different salts ( carbonates, phosphates, chlorides). The salt concentration was varied from 0.05 to a maximum of 1.7 M. The effect of the...
Article
Full-text available
The effect of cholesterol on the formation and properties of bilayer lipid membranes deposited on polyelectrolyte multilayered capsules was studied. The permeability of lipid/cholesterol coated capsules for NaCl was derived from osmotic response experiments and ranged from 1.45 x 10(-8) to 2.9 x 10(-8) m.s(-1), which corresponds to a lipid layer co...
Chapter
Full-text available
Kobayashi K, published in Tokyo: ID: 366720.0, MPI für Kolloid- und Grenzflächenforschung / Grenzflächen / Multifunctional Polymeric Micro- and Nanosized Capsules
Article
Full-text available
H.Bäumler, A. Krabi, R. Mitlöhner, R. Georgieva, P. Rösch, C. Kelemen, G. Artmann, H. Kiesewetter: see copy attached
Article
The permeability of ions and small polar molecules through polyelectrolyte multilayer capsules templated on red blood cells was studied by means of confocal microscopy and electrorotation. Capsules were obtained by removing the cell after polyelectrolyte multilayer formation by means of NaOCl treatment. This procedure results in cross-linking of po...
Article
Charged phospholipids and mixtures of charged phospholipids with zwitterionic lipids were adsorbed onto polyelectrolyte capsules templated on erythrocytes. The assembly was proved by means of electrophoretic mobility measurements, confocal laser scanning microscopy and flow cytometry. Freeze-fracture electron microscopy proved that the phospholipid...
Article
Three-dimensional ultrathin polymer shells have been produced by a combination of step-by-step adsorption of polyelectrolytes on glutaraldehyde-treated human erythrocytes and subsequent solubilization of the cytoplasmatic constituents by means of a deproteinizing agent. The obtained hollow films preserve both the size and shape of the templating ce...