Tankoslojna podloga za dvoslojeve lipida

A strip thin-film support consisting of compact or planar interdigitated array electrodes and glass substrate is presented. A novel method of forming of s-BLM on the thin metallic film (sl-BLM) has been developed. Electromechanical characteristics of BLM were studied and the measured value of elasticity modulus perpendicular to the bilayer plane was found to change considerably with increasing dc voltage. The presented results evidence the fact that the values of E^ are are strongly influenced by the degree of roughness of the metal surface. It is shown that sl-BLM modified by electron carrier can be used as a simple pH sensor.Opisuje se podloga u obliku tanke trake koja se sastoji od nizova kompaktnih ili ravnih elektroda i staklene osnove. Razvijena je nova metoda pripreme dvoslojne lipidne membrane (s-BLM) na tankom metalnom sloju (sl-BLM). Proučavana su elektromehanička svojstva BLM i mjeren je modul elastičnosti okomito na površinu dvosloja za koji se ustanovilo da se znatno mijenja s DC naponom. Izloženi rezultati ukazuju da na vrijednosti elastičnog modula E⊥ jako utječe stupanj neravnosti površine metala. Izmijenjen sl-BLM može se upotrebljavati kao jednostavna pH proba

Lipid-coated ruthenium dendrimer conjugated with doxorubicin in anti-cancer drug delivery: Introducing protocols

One of the major limitations for the treatment of many diseases is an inability of drugs to cross the cell membrane barrier. Different kinds of carriers are being investigated to improve drug bioavailability. Among them, lipid or polymer-based systems are of special interest due to their biocompatibility. In our study, we combined dendritic and liposomal carriers and analysed the biochemical and biophysical properties of these formulations. Two preparation methods of Liposomal Locked-in Dendrimers (LLDs) systems have been established and compared. Carbosilane ruthenium metallodendrimer was complexed with an anti-cancer drug (doxorubicin) and locked in a liposomal structure, using both techniques. The LLDs systems formed by hydrophilic locking had more efficient transfection profiles and interacted with the erythrocyte membrane better than systems using the hydrophobic method. The results indicate these systems have improved transfection properties when compared to noncomplexed components. The coating of dendrimers with lipids significantly reduced their hemotoxicity and cytotoxicity. The nanometric size, low polydispersity index and reduced positive zeta potential of such complexes made them attractive for future application in drug delivery. The formulations prepared by the hydrophobic locking protocol were not effective and will not be considered furthermore as prospective drug delivery systems. In contrast, the formulations formed by the hydrophilic loading method have shown promising results where the cytotoxicity of LLD systems with doxorubicin was more effective against cancer than normal cells

Electrochemical Immuno- and Aptasensors for Mycotoxin Determination

Modern analysis of food and feed is mostly focused on development of fast and reliable portable devices intended for field applications. In this review, electrochemical biosensors based on immunological reactions and aptamers are considered in the determination of mycotoxins as one of most common contaminants able to negatively affect human health. The characteristics of biosensors are considered from the point of view of general principles of bioreceptor implementation and signal transduction providing sub-nanomolar detection limits of mycotoxins. Moreover, the modern trends of bioreceptor selection and modification are discussed as well as future trends of biosensor development for mycotoxin determination are considered

Electrochemical Detection of Heavy Metal Ions Based on Nanocomposite Materials

Heavy metal ions (HMIs) have acute toxic effects on health and are dangerous for human existence and the ecosystem. Therefore, their sensitive and selective detection is of great importance. In recent years, various nanocomposite materials have been used by researchers for the detection of HMIs by using various modalities of electrochemical techniques. This review summarizes the recent advances in developing electrochemical sensors based on numerous nanocomposite materials for detecting HMIs. Nanocomposite materials, such as metal–organic frameworks (MOFs), organic conducting polymer (OCPs), carbon nanotubes (CNTs), graphene oxide (GO), graphene/reduced graphene oxide (rGO), graphitic carbon nitride, metal oxide, chitosan, MXenes, metal nanoparticle-based nanocomposites, etc., have been explored by various researchers to improve the sensing properties of electrochemical sensors. This review emphasizes nanocomposite materials’ synthesis and characterization techniques, modalities for HMI detection using electrochemical techniques, and electrochemical sensors. Moreover, this review highlights the development of portable biosensors for detecting HMIs in real-world scenarios, such as environmental monitoring, food safety, and clinical diagnosis. This review also demonstrates the importance of electrochemical sensors based on nanocomposite materials as a reliable, sensitive, and selective tool for detecting HMIs

Bilayer lipid membranes : stucture and mechanical properties

indexBibl. : 431 - 436vii, 436 hlm. : il. ; 23 c

Detection of Sub-Nanomolar Concentration of Trypsin by Thicken-Shear Mode (TSM) Acoustic Wave Biosensor

The determination of protease activity is very important for disease diagnosis, drug development, and quality and safety assurance for dairy products. Therefore, the development of low-cost methods for assessing protease activity is critical. Here, we demonstrate that an acoustic wave-based biosensor operated in the thickness-shear mode (TSM) enables the low-cost detection of protease activity in real time. The TSM sensor was based on a protein substrate (PS) β-casein immobilized on a piezoelectric quartz crystal electrode. The β-casein layer was immobilized onto a gold surface by a carboxylate terminated self-assembled monolayer (SAM) of 11-mercaptoundecanoic acid (MUA). The carboxylic acid terminal was activated by the reaction of a mixture of water- soluble N-(3-Dimethylaminopropyl)-N0-ethylcarbodiimide (EDC) and N–Hydroxysuccinimide (NHS) on the electrode surfaces. We demonstrated that β-casein can form a stable assembly on a piezoelectric quartz crystal electrode. After an enzymatic reaction with trypsin, it cleaved the surface-bound β-casein substrate, which increased the frequency of the crystal in a sigmoidal manner. Trypsin was detected in the range of concentrations from 1 to 50 nM. The limit of detection was 0.2 nM. Initial reaction rates measured at different enzyme concentrations have been used to construct a calibration curve. Considering the results obtained, we believe that the TSM biosensor is a useful tool for protease analysis

Polymer Nanoparticles and Nanomotors Modified by DNA/RNA Aptamers and Antibodies in Targeted Therapy of Cancer

Polymer nanoparticles and nano/micromotors are novel nanostructures that are of increased interest especially in the diagnosis and therapy of cancer. These structures are modified by antibodies or nucleic acid aptamers and can recognize the cancer markers at the membrane of the cancer cells or in the intracellular side. They can serve as a cargo for targeted transport of drugs or nucleic acids in chemo- immuno- or gene therapy. The various mechanisms, such as enzyme, ultrasound, magnetic, electrical, or light, served as a driving force for nano/micromotors, allowing their transport into the cells. This review is focused on the recent achievements in the development of polymer nanoparticles and nano/micromotors modified by antibodies and nucleic acid aptamers. The methods of preparation of polymer nanoparticles, their structure and properties are provided together with those for synthesis and the application of nano/micromotors. The various mechanisms of the driving of nano/micromotors such as chemical, light, ultrasound, electric and magnetic fields are explained. The targeting drug delivery is based on the modification of nanostructures by receptors such as nucleic acid aptamers and antibodies. Special focus is therefore on the method of selection aptamers for recognition cancer markers as well as on the comparison of the properties of nucleic acid aptamers and antibodies. The methods of immobilization of aptamers at the nanoparticles and nano/micromotors are provided. Examples of applications of polymer nanoparticles and nano/micromotors in targeted delivery and in controlled drug release are presented. The future perspectives of biomimetic nanostructures in personalized nanomedicine are also discussed