Liam Yourston - Academia.edu (original) (raw)

Papers by Liam Yourston

Research paper thumbnail of Optical, structural, and biological properties of silver nanoclusters formed within the loop of a C-12 hairpin sequence

Nanoscale Advances

Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic struc... more Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic structures where silver atoms are organized in a particular geometry. The composition and geometry of AgNCs defines their optical and biological properties.

Research paper thumbnail of Detection of cancer‐associated miRNA using a fluorescence switch of AgNC@NA and guanine‐rich overhang sequences

Luminescence

DNA‐templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterial with advantageous o... more 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)12 when adjacent G‐rich sequences (dGN, with N = 3–15) were added. The ‘red’ emission of AgNC@dC12 with λMAX = 660 nm dramatically changed upon the addition of a G‐rich overhang with NG = 15. The pattern of the emission–excitation matrix (EEM) suggested the emergence of two new emissive states at λMAX = 575 nm and λMAX = 710 nm. The appearance of these peaks provides an effective way to design biosensors capable of detecting specific nucleic acid sequences with low fluorescence backgrounds. We used this property to construct an NA‐based switch that brings AgNC and the G overhang near one another, turning ‘ON’ the new fluorescence peaks only when a specific miRNA sequence is present. N...

Research paper thumbnail of Hg2+ Detection with Rational Design of DNA-Templated Fluorescent Silver Nanoclusters

Processes

Atomically precise silver nanoclusters (AgNCs) are small nanostructures consisting of only a few ... more Atomically precise silver nanoclusters (AgNCs) are small nanostructures consisting of only a few atoms of silver. The combination of AgNCs with cytosine-rich single-stranded oligonucleotides results in DNA-templated silver nanoclusters (DNA-AgNCs). DNA-AgNCs are highly luminescent and can be engineered with reproducible and unique fluorescent properties. Furthermore, using nucleic acids as templates for the synthesis of AgNCs provides additional practical benefits by expanding optical activity beyond the visible spectral range and creating the possibility for color tunability. In this study, we explore DNA oligonucleotides designed to fold into hairpin-loop (HL) structures which modulate optical properties of AgNCs based on the size of the loop containing different number of cytosines (HL-CN). Depending on the size of the loop, AgNCs can be manufactured to have either single or multiple emissive states. Such hairpin-loop structures provide an additional stability for AgNCs and furth...

Research paper thumbnail of DNA-Templated Fluorescent Silver Nanoclusters Inhibit Bacterial Growth While Being Non-Toxic to Mammalian Cells

Molecules

Silver has a long history of antibacterial effectiveness. The combination of atomically precise m... more 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. In this work, we characterize the sequence-specific fluorescence and composition of four representative DNA-AgNCs, compare their corresponding antibacterial effectiveness at different pH, and assess cytotoxicity to several mammalian cell lines.

Research paper thumbnail of Tuning properties of silver nanoclusters with RNA nanoring assemblies

Nanoscale

Combining atomically resolved DNA-templated silver nanoclusters (AgNCs) with nucleic acid nanotec... more Combining atomically resolved DNA-templated silver nanoclusters (AgNCs) with nucleic acid nanotechnology opens new exciting possibilities for engineering bioinorganic nanomaterials with uniquely tunable properties.

Research paper thumbnail of First Step Towards Larger DNA-Based Assemblies of Fluorescent Silver Nanoclusters: Template Design and Detailed Characterization of Optical Properties

Nanomaterials

Besides being a passive carrier of genetic information, DNA can also serve as an architecture tem... more 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. The effects of close proximity of the double-stranded DNA, the directionality of templating single-stranded sequence, and conformational heterogeneity of the template are presented. We observe differences between designs containing the same AgNC templating sequence—twelve consecutive cytosines, (dC)12. AgNCs synthesized on a single “basic” templating element, (dC)12, emit in “red”. The a...

Research paper thumbnail of Micro RNA Sensing with Green Emitting Silver Nanoclusters

Molecules

Micro RNA (miR) are regulatory non-coding RNA molecules, which contain a small number of nucleoti... more 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. Other functions include cardiovascular and neural development, stem cell differentiation, apoptosis, and tumors. In tumors, some miRs can function as oncogenes, others as tumor suppressors. Levels of certain miR molecules reflect cellular events, both normal and pathological. Therefore, miR molecules can be used as biomarkers for disease diagnosis and prognosis. One of these promising molecules is miR-21, which can serve as a biomarker with high potential for early diagnosis of various types of cancer. Here, we present a novel design of miR detection and demonstrate its efficacy on miR-21. The design employs emissive properties of DNA-silver n...

Research paper thumbnail of Optical, structural, and biological properties of silver nanoclusters formed within the loop of a C-12 hairpin sequence

Nanoscale Advances

Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic struc... more Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic structures where silver atoms are organized in a particular geometry. The composition and geometry of AgNCs defines their optical and biological properties.

Research paper thumbnail of Detection of cancer‐associated miRNA using a fluorescence switch of AgNC@NA and guanine‐rich overhang sequences

Luminescence

DNA‐templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterial with advantageous o... more 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)12 when adjacent G‐rich sequences (dGN, with N = 3–15) were added. The ‘red’ emission of AgNC@dC12 with λMAX = 660 nm dramatically changed upon the addition of a G‐rich overhang with NG = 15. The pattern of the emission–excitation matrix (EEM) suggested the emergence of two new emissive states at λMAX = 575 nm and λMAX = 710 nm. The appearance of these peaks provides an effective way to design biosensors capable of detecting specific nucleic acid sequences with low fluorescence backgrounds. We used this property to construct an NA‐based switch that brings AgNC and the G overhang near one another, turning ‘ON’ the new fluorescence peaks only when a specific miRNA sequence is present. N...

Research paper thumbnail of Hg2+ Detection with Rational Design of DNA-Templated Fluorescent Silver Nanoclusters

Processes

Atomically precise silver nanoclusters (AgNCs) are small nanostructures consisting of only a few ... more Atomically precise silver nanoclusters (AgNCs) are small nanostructures consisting of only a few atoms of silver. The combination of AgNCs with cytosine-rich single-stranded oligonucleotides results in DNA-templated silver nanoclusters (DNA-AgNCs). DNA-AgNCs are highly luminescent and can be engineered with reproducible and unique fluorescent properties. Furthermore, using nucleic acids as templates for the synthesis of AgNCs provides additional practical benefits by expanding optical activity beyond the visible spectral range and creating the possibility for color tunability. In this study, we explore DNA oligonucleotides designed to fold into hairpin-loop (HL) structures which modulate optical properties of AgNCs based on the size of the loop containing different number of cytosines (HL-CN). Depending on the size of the loop, AgNCs can be manufactured to have either single or multiple emissive states. Such hairpin-loop structures provide an additional stability for AgNCs and furth...

Research paper thumbnail of DNA-Templated Fluorescent Silver Nanoclusters Inhibit Bacterial Growth While Being Non-Toxic to Mammalian Cells

Molecules

Silver has a long history of antibacterial effectiveness. The combination of atomically precise m... more 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. In this work, we characterize the sequence-specific fluorescence and composition of four representative DNA-AgNCs, compare their corresponding antibacterial effectiveness at different pH, and assess cytotoxicity to several mammalian cell lines.

Research paper thumbnail of Tuning properties of silver nanoclusters with RNA nanoring assemblies

Nanoscale

Combining atomically resolved DNA-templated silver nanoclusters (AgNCs) with nucleic acid nanotec... more Combining atomically resolved DNA-templated silver nanoclusters (AgNCs) with nucleic acid nanotechnology opens new exciting possibilities for engineering bioinorganic nanomaterials with uniquely tunable properties.

Research paper thumbnail of First Step Towards Larger DNA-Based Assemblies of Fluorescent Silver Nanoclusters: Template Design and Detailed Characterization of Optical Properties

Nanomaterials

Besides being a passive carrier of genetic information, DNA can also serve as an architecture tem... more 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. The effects of close proximity of the double-stranded DNA, the directionality of templating single-stranded sequence, and conformational heterogeneity of the template are presented. We observe differences between designs containing the same AgNC templating sequence—twelve consecutive cytosines, (dC)12. AgNCs synthesized on a single “basic” templating element, (dC)12, emit in “red”. The a...

Research paper thumbnail of Micro RNA Sensing with Green Emitting Silver Nanoclusters

Molecules

Micro RNA (miR) are regulatory non-coding RNA molecules, which contain a small number of nucleoti... more 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. Other functions include cardiovascular and neural development, stem cell differentiation, apoptosis, and tumors. In tumors, some miRs can function as oncogenes, others as tumor suppressors. Levels of certain miR molecules reflect cellular events, both normal and pathological. Therefore, miR molecules can be used as biomarkers for disease diagnosis and prognosis. One of these promising molecules is miR-21, which can serve as a biomarker with high potential for early diagnosis of various types of cancer. Here, we present a novel design of miR detection and demonstrate its efficacy on miR-21. The design employs emissive properties of DNA-silver n...