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Small (Weinheim An Der Bergstrasse,... Mar 2023Super-resolution microscopy has revolutionized how researchers characterize samples in the life sciences in the last decades. Amongst methods employing single-molecule...
Super-resolution microscopy has revolutionized how researchers characterize samples in the life sciences in the last decades. Amongst methods employing single-molecule localization microscopy, DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) is a relatively easy-to-implement method that uses the programmable and repetitive binding of dye-labeled DNA imager strands to their respective docking strands. Recently developed Peptide-PAINT replaces the interaction of oligonucleotides by short coiled-coil peptide sequences leading to an improved labeling scheme by reducing linkage errors to target proteins. However, only one coiled-coil pair is currently available for Peptide-PAINT, preventing multiplexed imaging. In this study, the initial Peptide-PAINT E/K coil is improved by modifying its length for optimized binding kinetics leading to improved localization precisions. Additionally, an orthogonal P3/P4 coil pair is introduced, enabling 2-plex Peptide-PAINT imaging and benchmarking its performance and orthogonality using single-molecule and DNA origami assays. Finally, the P3/P4 peptide pair is used to image the human epidermal growth factor receptors 2 (ErbB2/Her2) in 2D and 3D at the single receptor level using genetically encoded peptide tags.
Topics: Humans; Microscopy, Fluorescence; DNA; Oligonucleotides; Nanotechnology; Peptides
PubMed: 36642829
DOI: 10.1002/smll.202206347 -
Small (Weinheim An Der Bergstrasse,... Mar 2023Heparin is a commonly applied blood anticoagulant agent in clinical use. After treatment, excess heparin needs to be removed to circumvent side effects and recover the...
Heparin is a commonly applied blood anticoagulant agent in clinical use. After treatment, excess heparin needs to be removed to circumvent side effects and recover the blood-clotting cascade. Most existing heparin antidotes rely on direct heparin binding and complexation, yet selective compartmentalization and sequestration of heparin would be beneficial for safety and efficiency. However, such systems have remained elusive. Herein, a semipermeable protein-based microcompartment (proteinosome) is loaded with a highly positively charged chitosan derivative, which can induce electrostatics-driven internalization of anionic guest molecules inside the compartment. Chitosan-loaded proteinosomes are subsequently employed to capture heparin, and an excellent heparin-scavenging performance is demonstrated under physiologically relevant conditions. Both the highly positive scavenger and the polyelectrolyte complex are confined and shielded by the protein compartment in a time-dependent manner. Moreover, selective heparin-scavenging behavior over serum albumin is realized through adjusting the localized scavenger or surrounding salt concentrations at application-relevant circumstances. In vitro studies reveal that the cytotoxicity of the cationic scavenger and the produced polyelectrolyte complex is reduced by protocell shielding. Therefore, the proteinosome-based systems may present a novel polyelectrolyte-scavenging method for biomedical applications.
Topics: Heparin; Artificial Cells; Chitosan; Polyelectrolytes; Proteins
PubMed: 35570377
DOI: 10.1002/smll.202201790 -
Small (Weinheim An Der Bergstrasse,... Oct 2022The photoelastic effect has many uses in mechanics today, but it is usually disregarded in flexible materials. Using 2-phenoxyethyl acrylate as a monomer and...
The photoelastic effect has many uses in mechanics today, but it is usually disregarded in flexible materials. Using 2-phenoxyethyl acrylate as a monomer and 4-cyano-4'-pentylbiphenyl (5CB) as a solvent, a multiple responsive photoelastic organogel (PO) with strong birefringence but low modulus is created. 5CB is a liquid crystal molecule that does not participate in the polymerization process and is always present as tiny molecules in the polymer. It endows the PO low modulus and high birefringence, as well as the ability to drive the birefringence using an electric field. This PO not only has high sensitivity and fast response as a photoelastic strain sensor, but also has a very sensitive response to heat, especially in the range of human body temperature. It also has a high dielectric constant and a strong correlation between the interference color and the applied electric field, allowing for easy writing and erasure of encrypted data. This unique multisignal response feature and low modulus that mimics human skin bring up new opportunities in the potential applications such as multiple information encryption, anticounterfeiting, and multifunctional wearable sensors.
Topics: Acrylates; Biphenyl Compounds; Humans; Liquid Crystals; Nitriles; Polymers; Solvents
PubMed: 36058641
DOI: 10.1002/smll.202204140 -
Small (Weinheim An Der Bergstrasse,... Aug 2019Solid-state ion nanochannels/nanopores, the biomimetic products of biological ion channels, are promising materials in real-world applications due to their robust... (Review)
Review
Solid-state ion nanochannels/nanopores, the biomimetic products of biological ion channels, are promising materials in real-world applications due to their robust mechanical and controllable chemical properties. Functionalizations of solid-state ion nanochannels/nanopores by biomolecules pave a wide way for the introduction of varied properties from biomolecules to solid-state ion nanochannels/nanopores, making them smart in response to analytes or external stimuli and regulating the transport of ions/molecules. In this review, two features for nanochannels/nanopores functionalized by biomolecules are abstracted, i.e., specificity and signal amplification. Both of the two features are demonstrated from three kinds of nanochannels/nanopores: nucleic acid-functionalized nanochannels/nanopores, protein-functionalized nanochannels/nanopores, and small biomolecule-functionalized nanochannels/nanopores, respectively. Meanwhile, the fundamental mechanisms of these combinations between biomolecules and nanochannels/nanopores are explored, providing reasonable constructs for applications in sensing, transport, and energy conversion. And then, the techniques of functionalizations and the basic principle about biomolecules onto the solid-state ion nanochannels/nanopores are summarized. Finally, some views about the future developments of the biomolecule-functionalized nanochannels/nanopores are proposed.
Topics: Fluorescence; Ions; Nanopores; Nanotechnology; Nucleic Acids; Signal Processing, Computer-Assisted
PubMed: 30756522
DOI: 10.1002/smll.201804878 -
Small (Weinheim An Der Bergstrasse,... Aug 2022Biofunctionalized nanoparticles are increasingly used in biomedical applications including sensing, targeted delivery, and hyperthermia. However, laser excitation and...
Biofunctionalized nanoparticles are increasingly used in biomedical applications including sensing, targeted delivery, and hyperthermia. However, laser excitation and associated heating of the nanomaterials may alter the structure and interactions of the conjugated biomolecules. Currently no method exists that directly monitors the local temperature near the material's interface where the conjugated biomolecules are. Here, a nanothermometer is reported based on DNA-mediated points accumulation for imaging nanoscale topography (DNA-PAINT) microscopy. The temperature dependent kinetics of repeated and reversible DNA interactions provide a direct readout of the local interfacial temperature. The accuracy and precision of the method is demonstrated by measuring the interfacial temperature of many individual gold nanoparticles in parallel, with a precision of 1 K. In agreement with numerical models, large particle-to-particle differences in the interfacial temperature are found due to underlying differences in optical and thermal properties. In addition, the reversible DNA interactions enable the tracking of interfacial temperature in real-time with intervals of a few minutes. This method does not require prior knowledge of the optical and thermal properties of the sample, and therefore opens the window to understanding and controlling interfacial heating in a wide range of nanomaterials.
Topics: DNA; Gold; Metal Nanoparticles; Microscopy; Nanostructures
PubMed: 35789234
DOI: 10.1002/smll.202201602 -
Small (Weinheim An Der Bergstrasse,... Nov 2019Carbon dots (C-dots) are generally separated into graphene quantum dots (GQDs) and carbon nanodots (CNDs) based on their respective top-down and bottom-up preparation... (Review)
Review
Carbon dots (C-dots) are generally separated into graphene quantum dots (GQDs) and carbon nanodots (CNDs) based on their respective top-down and bottom-up preparation processes. However, GQDs can be prepared by carbonization of small-molecule precursors as revealed with unconventional preparation strategies. Thus, it is their structures rather than their precursors and preparation strategy that govern whether C-dots are GQDs or CNDs. Here, the composites, structure, and electronic properties of C-dots are discussed. C-dots generally consist of a graphite-like core and amorphous oxygen-containing shell. When graphite becomes C-dots, its conduction and valence bands are separated, and the quantum confinement effect appears. Combined with the light-harvesting ability inherited from graphite, electrons in the core of C-dots are transferred from conduction to valence bands, leading to electron-hole pair formation upon light excitation. The photoexcitation activities, such as photovoltaic conversion, photocatalysis, and photodynamic therapy, are influenced by the electronic properties of the core. Different to the semiconductor properties of core, the C-dot shell is electrochemically active, leading to electrochemiluminescence (ECL). The oxygen-containing groups in shell can conjugate to functional species for use in imaging and therapy. The applications of C-dots beyond photoluminescence, including ECL, solar photovoltaics, photocatalysis, and theranostics, are reviewed.
PubMed: 31240816
DOI: 10.1002/smll.201901803 -
Small (Weinheim An Der Bergstrasse,... Dec 2020Their tunable optical properties and versatile surface functionalization have sparked applications of plasmonic assemblies in the fields of biosensing, nonlinear optics,... (Review)
Review
Their tunable optical properties and versatile surface functionalization have sparked applications of plasmonic assemblies in the fields of biosensing, nonlinear optics, and photonics. Particularly, in the field of biosensing, rapid advances have occurred in the use of plasmonic assemblies for real-time single-molecule sensing. Compared to individual particles, the use of assemblies as sensors provides stronger signals, more control over the optical properties, and access to a broader range of timescales. In the past years, they have been used to directly reveal single-molecule interactions, mechanical properties, and conformational dynamics. This review summarizes the development of real-time single-molecule sensors built around plasmonic assemblies. First, a brief overview of their optical properties is given, and then recent applications are described. The current challenges in the field and suggestions to overcome those challenges are discussed in detail. Their stability, specificity, and sensitivity as sensors provide a complementary approach to other single-molecule techniques like force spectroscopy and single-molecule fluorescence. In future applications, the impact in real-time sensing on ultralong timescales (hours) and ultrashort timescales (sub-millisecond), time windows that are difficult to access using other techniques, is particularly foreseen.
Topics: Biosensing Techniques; Nanostructures; Nanotechnology; Optics and Photonics; Surface Plasmon Resonance
PubMed: 33258287
DOI: 10.1002/smll.202003934 -
Small (Weinheim An Der Bergstrasse,... Sep 2023Clustered regularly interspaced short palindromic repeats (CRISPR) and polymerases are powerful enzymes and their diverse applications in genomics, proteomics, and... (Review)
Review
Clustered regularly interspaced short palindromic repeats (CRISPR) and polymerases are powerful enzymes and their diverse applications in genomics, proteomics, and transcriptomics have revolutionized the biotechnology industry today. CRISPR has been widely adopted for genomic editing applications and Polymerases can efficiently amplify genomic transcripts via polymerase chain reaction (PCR). Further investigations into these enzymes can reveal specific details about their mechanisms that greatly expand their use. Single-molecule techniques are an effective way to probe enzymatic mechanisms because they may resolve intermediary conformations and states with greater detail than ensemble or bulk biosensing techniques. This review discusses various techniques for sensing and manipulation of single biomolecules that can help facilitate and expedite these discoveries. Each platform is categorized as optical, mechanical, or electronic. The methods, operating principles, outputs, and utility of each technique are briefly introduced, followed by a discussion of their applications to monitor and control CRISPR and Polymerases at the single molecule level, and closing with a brief overview of their limitations and future prospects.
Topics: CRISPR-Cas Systems; Clustered Regularly Interspaced Short Palindromic Repeats; Gene Editing; Biotechnology
PubMed: 37226388
DOI: 10.1002/smll.202300328 -
Small (Weinheim An Der Bergstrasse,... Apr 2024Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate... (Review)
Review
Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate autophagy by inhibiting the mTOR pathway, which is essential for cell regulation. This can clear damaged components but may cause cytotoxicity with prolonged use. Nanoparticles, however, induce autophagy, often causing oxidative stress, through broader cellular interactions and can lead to a targeted form known as "xenophagy." Their impact varies with their properties but can be harnessed therapeutically. In this review, the autophagy induced by nanoparticles is explored and small molecules across four dimensions: the mechanisms behind autophagy induction, the outcomes of such induction, the toxicological effects on cellular autophagy, and the therapeutic potential of employing autophagy triggered by nanoparticles or small molecules. Although small molecules and nanoparticles each induce autophagy through different pathways and lead to diverse effects, both represent invaluable tools in cell biology, nanomedicine, and drug discovery, offering unique insights and therapeutic opportunities.
PubMed: 38616767
DOI: 10.1002/smll.202310966 -
Small (Weinheim An Der Bergstrasse,... Jun 2022The nanopore sensing technique is an emerging method of detecting single molecules, and extensive research has gone into various fields, including nanopore sequencing... (Review)
Review
The nanopore sensing technique is an emerging method of detecting single molecules, and extensive research has gone into various fields, including nanopore sequencing and other applications of single-molecule studies. Recently, several researchers have explored the specific ion effects in nanopore channels, enabling a unique understanding of the Hofmeister effect at the single-molecule level. Herein, the recent advances of using nanopore sensing techniques are reviewed to study the Hofmeister effect and the physicochemical mechanism of this process is attempted. The challenges and goals are also discussed for the future in this field.
Topics: Nanopores; Nanotechnology
PubMed: 35484475
DOI: 10.1002/smll.202200921