Publications by authors named "Alexey Krasnoslobodtsev"

Self-powered biosensors are innovative devices that can detect and analyze biological or chemical substances without the need for an external power source. These biosensors can convert energy from the surrounding environment or the analyte itself into electrical signals for sensing and data transmission. The self-powered nature of these biosensors offers several advantages, such as portability, autonomy, and reduced waste generation from disposable batteries.

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The protocol described in this chapter allows for acquiring topography images of RNA-based nanoring structures and assessing their dynamic properties using atomic force microscopy (AFM) imaging. AFM is an indispensable tool for characterization of nucleic acid-based nanostructures with the exceptional capability of observing complexes in the range of a few nanometers. This method can visualize structural characteristics and evaluate differences between individual structurally different RNA nanorings.

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Particle tracking (PT) microrheology is a passive microrheological approach that characterizes material properties of soft matter. Multicomponent materials with the ability to create extensive crosslinking, such as supra-assemblies, may exhibit a complex interplay of viscous and elastic properties with a substantial contribution of liquid phase still diffusing through the system. Microrheology analyzes the motion of microscopic beads immersed in a sample, making it possible to evaluate the rheological properties of biological supra-assemblies.

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Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic structures where silver atoms are organized in a particular geometry. DNA can effectively template and stabilize these novel fluorescent AgNCs. Only a few atoms in size - the properties of nanoclusters can be tuned using only single nucleobase replacement of C-rich templating DNA sequences.

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Nanomaterials have been extensively explored in developing sensors due to their unique properties, contributing to the development of reliable sensor designs with improved sensitivity and specificity. Herein, we propose the construction of a fluorescent/electrochemical dual-mode self-powered biosensor for advanced biosensing using DNA-templated silver nanoclusters (AgNCs@DNA). AgNC@DNA, due to its small size, exhibits advantageous characteristics as an optical probe.

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DNA-templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterial with advantageous optical properties. Only a few atoms in size, the fluorescence of nanoclusters can be tuned using DNA overhangs. In this study, we explored the properties of AgNCs manufactured on a short single-stranded (dC) when adjacent G-rich sequences (dG , with N = 3-15) were added.

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Sensitive detection of biomarkers is very critical in the diagnosis, management, and monitoring of diseases. Recent efforts have suggested that bioassays using surface-enhanced Raman scattering as a signal read-out strategy possess certain unique beneficial features in terms of sensitivity and low limits of detection which set this method apart from its counterparts such as fluorescence, phosphorescence, and radiolabeling. Surface-enhanced Raman scattering (SERS) has also emerged as an ideal choice for the development of multiplexed bioassays.

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SERS immunoassay biosensors hold immense potential for clinical diagnostics due to their high sensitivity and growing interest in multi-marker panels. However, their development has been hindered by difficulties in designing compatible extrinsic Raman labels. Prior studies have largely focused on spectroscopic characteristics in selecting Raman reporter molecules (RRMs) for multiplexing since the presence of well-differentiated spectra is essential for simultaneous detection.

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Ribonucleic acid (RNA) nanotechnology platforms have the potential of harboring therapeutics for delivery in disease treatment. However, the nonspecific interaction between the harbored hydrophobic drugs and cells or other components before reaching the diseased site has been an obstacle in drug delivery. Here we report an encapsulation strategy to prevent such nonspecific hydrophobic interactions and based on a self-assembled three-dimensional (3D) RNA nanocage.

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Silver has a long history of antibacterial effectiveness. The combination of atomically precise metal nanoclusters with the field of nucleic acid nanotechnology has given rise to DNA-templated silver nanoclusters (DNA-AgNCs) which can be engineered with reproducible and unique fluorescent properties and antibacterial activity. Furthermore, cytosine-rich single-stranded DNA oligonucleotides designed to fold into hairpin structures improve the stability of AgNCs and additionally modulate their antibacterial properties and the quality of observed fluorescent signals.

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With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Here we report rechargeable aluminum-ion batteries capable of reaching a high specific capacity of 200 mAh g. When liquid metal is further used to lower the energy barrier from the anode, fastest charging rate of 10 C (duration of 0.

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Combining atomically resolved DNA-templated silver nanoclusters (AgNCs) with nucleic acid nanotechnology opens new exciting possibilities for engineering bioinorganic nanomaterials with uniquely tunable properties. In this unforeseen cooperation, nucleic acids not only drive the formation of AgNCs but also promote their spatial organization in supra-assemblies. In this work, we confirm the feasibility of this approach using programmable RNA rings to control formation and optical properteis of six individual AgNCs.

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Micro RNA (miR) are regulatory non-coding RNA molecules, which contain a small number of nucleotides ~18-28 nt. There are many various miR sequences found in plants and animals that perform important functions in developmental, metabolic, and disease processes. miRs can bind to complementary sequences within mRNA molecules thus silencing mRNA.

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Background: The Golgi apparatus undergoes disorganization in response to stress, but it is able to restore compact and perinuclear structure under recovery. This self-organization mechanism is significant for cellular homeostasis, but remains mostly elusive, as does the role of giantin, the largest Golgi matrix dimeric protein.

Methods: In HeLa and different prostate cancer cells, we used the model of cellular stress induced by Brefeldin A (BFA).

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The protocol described herein allows for acquiring topography images of DNA-protein complexes using Atomic Force Microscopy imaging. Since the very beginning of this method, AFM has been an indispensable tool for characterization of biomolecular complexes with exceptional capability of observing single complexes. This method can visualize structural characteristics of DNA-protein assemblies and evaluate differences between individual complexes.

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Besides being a passive carrier of genetic information, DNA can also serve as an architecture template for the synthesis of novel fluorescent nanomaterials that are arranged in a highly organized network of functional entities such as fluorescent silver nanoclusters (AgNCs). Only a few atoms in size, the properties of AgNCs can be tuned using a variety of templating DNA sequences, overhangs, and neighboring duplex regions. In this study, we explore the properties of AgNCs manufactured on a short DNA sequence-an individual element designed for a construction of a larger DNA-based functional assembly.

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Pancreatic cancer is a highly lethal malignancy. Lack of early diagnostic markers makes timely detection of pancreatic cancer a highly challenging endeavor. Exosomes have emerged as information-rich cancer specific biomarkers.

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Adipose-derived mesenchymal stem/stromal cells (ADMSC) are one of the major stromal cells in the breast cancer microenvironment that promote cancer progression. Previous studies on the effects of ADMSC on breast cancer metastasis and drug resistance, using two-dimensional (2D) cultures, remained inconclusive. In the present study, we compared cocultured ADMSC and human epidermal receptor 2 positive breast primary breast cancer cells (21PT) in 2D and three-dimensional (3D) cultures and then examined their response to doxorubicin (DOX).

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The blood-brain barrier (BBB) is an active and complex diffusion barrier that separates the circulating blood from the brain and extracellular fluid, regulates nutrient transportation, and provides protection against various toxic compounds and pathogens. Creating an in vitro microphysiological BBB system, particularly with relevant human cell types, will significantly facilitate the research of neuropharmaceutical drug delivery, screening, and transport, as well as improve our understanding of pathologies that are due to BBB damage. Currently, most of the in vitro BBB models are generated by culturing rodent astrocytes and endothelial cells, using commercially available transwell membranes.

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RNA is an attractive biopolymer for engineering self-assembling materials suitable for biomedical applications. Previously, programmable hexameric RNA rings were developed for the controlled delivery of up to six different functionalities. To increase the potential for functionalization with little impact on nanoparticle topology, we introduce gaps into the double-stranded regions of the RNA rings.

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Detection of biomarkers is of vital importance in disease detection, management, and monitoring of therapeutic efficacy. Extensive efforts have been devoted to the development of novel diagnostic methods that detect and quantify biomarkers with higher sensitivity and reliability, contributing to better disease diagnosis and prognosis. When it comes to such devastating diseases as cancer, these novel powerful methods allow for disease staging as well as detection of cancer at very early stages.

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Environmental factors, such as acidic pH, facilitate the assembly of α-synuclein (α-Syn) in aggregates, but the impact of pH on the very first step of α-Syn aggregation remains elusive. Recently, we developed a single-molecule approach that enabled us to measure directly the stability of α-Syn dimers. Unlabeled α-Syn monomers were immobilized on a substrate, and fluorophore-labeled monomers were added to the solution to allow them to form dimers with immobilized α-Syn monomers.

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Aggregation of prion proteins is the cause of various prion related diseases. The infectious form of prions, amyloid aggregates, exist as multiple strains. The strains are thought to represent structurally different prion protein molecules packed into amyloid aggregates, but the knowledge on the structure of different types of aggregates is limited.

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Immobilization is a key step involved in probing molecular interactions using single-molecule force spectroscopy methods, including atomic force microscopy (AFM). To our knowledge, we describe a novel approach termed flexible nanoarray (FNA) in which the interaction between the two internally immobilized amyloid β peptides is measured by pulling of the tether. The FNA tether was synthesized with nonnucleotide phosphoramidite monomers using the DNA synthesis chemistry.

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The aggregation of α-synuclein (α-Syn) is linked to Parkinson's disease. The mechanism of early aggregation steps and the effect of pathogenic single-point mutations remain elusive. We report here a single-molecule fluorescence study of α-Syn dimerization and the effect of mutations.

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