The detection of particular genetic sequences aids in the early detection and diagnosis of disease; permits monitoring of the health and state of the natural environment; and informs forensic investigations. To date, gene detection has relied on enzymatic amplification followed by optical readout. Though these technologies have advanced dramatically, the instruments and assays are costly and lack portability. The work presented herein addresses an urgent challenge: molecular diagnostics at the point-of-need. This work reports the first electronic chip capable of analyzing - directly, without amplification, and with clinically-relevant sensitivity - multiple genes of interest present in a clinical sample. It reports a dramatic acceleration in sample-to-answer times, with clinically actionable findings in minutes where legacy techniques take hours or days. The key to the sensitivity and speed of the biosensors reported herein lies in their architecture and morphology on multiple lengthscales. It is proven that hybridization-based assays employing a nucleic probe attached to a solid surface can only achieve efficient performance when displayed on a nanotextured surface. It is also discovered that these same sensing elements must reach tens of micrometers into solution to achieve rapid, sensitive detection of nucleic acids in clinical samples. As a result, the materials integrated onto the sensing chip reported herein are engineered on multiple lengthscales - from the nanometers to the tens of micrometers. Engineering is done through a combination of low-cost, convenient top-down photolithographic patterning; combined with hierarchically-designed bottom-up growth of electrodeposited sensing elements. The capstone of this work is a chip that distinguishes among different types of bacteria in an unpurified sample. The chip gives accurate answers in under half an hour when detecting bacteria at a level of 1.5 colony-forming-unit (cfu) per microliter. These speeds and sensitivies enable the application of this technology in point-of-need assays for infectious disease detection. Ultimately, the work showcases the power of bringing together techniques and principles from materials chemistry, biochemistry, applied physics, and electrical engineering to the solution of an important problem relevant to human health.

The detection of particular genetic sequences aids in the early detection and diagnosis of disease; permits monitoring of the health and state of the natural environment; and informs forensic investigations. To date, gene detection has relied on enzymatic amplification followed by optical readout. Though these technologies have advanced dramatically, the instruments and assays are costly and lack portability. The work presented herein addresses an urgent challenge: molecular diagnostics at the point-of-need. This work reports the first electronic chip capable of analyzing - directly, without amplification, and with clinically-relevant sensitivity - multiple genes of interest present in a clinical sample. It reports a dramatic acceleration in sample-to-answer times, with clinically actionable findings in minutes where legacy techniques take hours or days. The key to the sensitivity and speed of the biosensors reported herein lies in their architecture and morphology on multiple lengthscales. It is proven that hybridization-based assays employing a nucleic probe attached to a solid surface can only achieve efficient performance when displayed on a nanotextured surface. It is also discovered that these same sensing elements must reach tens of micrometers into solution to achieve rapid, sensitive detection of nucleic acids in clinical samples. As a result, the materials integrated onto the sensing chip reported herein are engineered on multiple lengthscales - from the nanometers to the tens of micrometers. Engineering is done through a combination of low-cost, convenient top-down photolithographic patterning; combined with hierarchically-designed bottom-up growth of electrodeposited sensing elements. The capstone of this work is a chip that distinguishes among different types of bacteria in an unpurified sample. The chip gives accurate answers in under half an hour when detecting bacteria at a level of 1.5 colony-forming-unit (cfu) per microliter. These speeds and sensitivies enable the application of this technology in point-of-need assays for infectious disease detection. Ultimately, the work showcases the power of bringing together techniques and principles from materials chemistry, biochemistry, applied physics, and electrical engineering to the solution of an important problem relevant to human health.

Biomarkers are biological measures used for clinical assessment, whether an individual has a particular medical condition or to monitor and predict health states in individuals. Sensitive detection and quantification of various biomarkers are essential for disease diagnostics. The majority of biomarker-based diagnostics examines the presence and quantity of a single biomarker. Since the symptoms of many diseases are alike, multiplexed biomarker tests are highly desirable. Furthermore, detection of multiple biomarkers would improve the accuracy of diagnosis as well as providing additional information about the prognosis. Microarray platforms have the potential for higher level of multiplexing for biomarker detection. However, conventional microarray technologies are limited by the sensitivity of assays. This dissertation describes how single-particle interferometric reflectance imaging sensor (SP-IRIS) overcomes the sensitivity issues in biomarker detection and its applications to biomolecular and cellular biomarker detection assays. SP-IRIS provides optical detection of individual nanoparticles when they are captured onto a simple reflecting substrate, providing single-molecule sensitivity. This technique can be used to detect natural nanoparticles (such as viruses) without labels as well as molecular analytes (proteins and nucleic acids) that are labeled with metallic nanoparticles. Moreover, the advancements in technology make SP-IRIS ideal for the detection of low abundance biomarkers. Utilization of light polarization in combination with plasmonic gold nanorods as labels enhances the signal-to-noise ratio in nanoparticle detection allowing for the use of low numerical aperture optics increasing the field-of-view, hence, the throughput and sensitivity. Additionally, the integration of a disposable microfluidic flow cell and dynamic particle tracking in kinetic measurements provide a robust, ultra-sensitive and automated diagnostic platform. This dissertation focuses on the development of biological assays demonstrating effective use of SP-IRIS as a clinical diagnostic platform. We discuss the development of protein, nucleic acid and biological nanoparticle detecting SP-IRIS microarrays. We demonstrate four digital detection platforms for Hepatitis B, microRNA, rare mutations in an oncogene, KRAS, and virus-like particle detection with ultra-high sensitivity. / 2022-09-28T00:00:00Z

The design of probes for the selective recognition of biopolymers (nucleic acids and proteins) is a fundamental task for studying, diagnosing, and treating diseases. Traditional methods utilize a single component (small molecule or oligonucleotide) that binds directly to the target biopolymer. However, many biopolymers are unable to be targeted with this approach. The overarching goal of this dissertation is to explore a new, binary approach for designing probes. The binary approach requires two components that cooperatively bind to the target, triggering a recognition event. The requisite binding of two-components allows the probes to have excellent selectivity and modularity. The binary approach was applied to design a new sensor, called operating cooperatively (OC) sensor, for recognition of nucleic acids, including selectively differentiating between single nucleotide polymorphisms (SNPs). An OC sensor contains two oligonucleotide probe strands, called O and C, each with two domains. The first domain contains a target recognition sequence, whereas the second domain is complementary to a molecular beacon (MB) probe. Binding of both probe strands to the fully matched analyte generates a full MB probe recognition site, allowing a MB to bind and report the presence of the target analyte. Importantly, we show that the OC sensor selectively discriminates between single nucleotide polymorphisms (SNPs) in DNA and RNA targets at room temperature, including those with stable secondary structures. Furthermore, the combinatorial use of OC sensors to create a DNA logic gate capable of analyzing DNA sequences of Mycobacterium tuberculosis is described. The binary approach was also applied to design covalent inhibitors for HIV-1 reverse transcriptase (RT). In this application, two separate pre-reactive groups were attached to a natural RT ligand, deoxythymidine triphosphate (dTTP). Upon binding of both dTTP analogs in the RT active site, the pre-reactive groups are brought into the proper proximity and react with each other forming an intermediate that subsequently reacts with an amino acid side chain from the RT. This leads to covalent modification of RT, and inhibition of its DNA polymerase activity. This concept was tested in vitro using dTTP analogs containing pre-reactive groups derived from ?-lactamase inhibitors clavulanic acid (CA) and sulbactam (SB). Importantly, our in vitro assays show that CA based inhibitors are more potent than zidovudine (AZT), a representative of the dominant class of RT inhibitors currently used in anti-HIV therapy. Furthermore, molecular dynamics simulations predict that complexes of RT with these analogs are stable, and point to possible reaction mechanisms. The inhibitors described in this work may serve as the basis for the development of the first covalent inhibitors for RT. Moreover, the pre-reactive groups used in this study can be used to design covalent inhibitors for other targets by attaching them to different ligands. Overall, the work presented herein establishes the binary approach as a straightforward way to develop new probes to selectively recognize nucleic acids and proteins.

No description available.

Protective antiviral immune responses require priming of naïve T cells by dendritic cells (DCs) that have matured sufficiently to produce co-stimulatory cell surface molecules and cytokines. Although only low levels of productive HIV-1 infection are detected in ex vivo DCs following HIV-1 challenge, those few cells exhibit innate activation. Experimentally bypassing blocks to entry and replication leads to more efficient transduction of DCs and maturation as indicated by production of interferons and interferon stimulated genes. Furthermore, similar innate activation occurs upon transduction of macrophages or CD4+ T cells. However, the mechanism by which HIV-1 is detected to activate innate immune signaling is not clear. The purpose of this thesis is to incorporate my data and observations into the understanding of HIV-1 innate detection and attempt to resolve seemingly conflicting observations. Reverse transcription and genomic integration are necessary for innate activation implying the need de novo transcription. Coding sequences are unnecessary save for those cis-acting sequences necessary for the HIV-1 life cycle. CRM1 dependent, HIV-1 unspliced RNA export is essential for innate activation. As intact viral sequence is unnecessary for transcription and export, defective proviruses may contribute to systemic inflammation seen in chronically infected individuals. These insights, are hoped to aid in the production of qualitatively better anti-retroviral drugs as well as in the design a protective HIV vaccine.

The aim of this report is to present a basis for development of an alternative quality control method for a part of the cancer monitoring technique DiviTum® by Biovica. The methods recommended are direct implementation of bromodeoxyuridine (BrdUTP), as well as biotin and digoxigenin systems. All methods show great potential since they do not require acquisition of new instruments or a change of microtiter plate. Further, all have specificity for the poly-A templates, include fewer steps, and are relatively cheap which aligns with the delimitations of the project. Additional methods are discussed to gain an overview of possible quality controls. However, these methods do not align with all the delimitations and are thus not recommended. An ethical analysis was conducted in which issues related to the suggested quality control methods were discussed. These were for example the potential for reusability of materials, and some ethical considerations that arise when handling biological samples from patients or donors. The results obtained are based on a literature study as well as a complementary interview.

Indiana University-Purdue University Indianapolis (IUPUI) / MicroRNAs (miRNA) are short, 18-24 nucleotide long noncoding RNAs. These small RNAs, which are initially transcribed in the nucleus, are transported into the cell cytoplasm where they regulate protein translation either through direct cleavage of mRNA, or indirect inhibition through binding to mRNA and disrupting the protein translation machinery. Recently, miRNAs have gained much attention due to their implication in numerous diseases and cancers. It has been found that heightened or lowered levels of miRNA in diseased cells vs. healthy cells are linked to disease progression. It is therefore immensely important to be able to detect these small molecules. Current detection methods of Northern blotting, microarrays, and qRT-PCR suffer from drawbacks including low sensitivity, a lack of simplicity, being semi-quantitative in nature, time-consuming, and requiring expensive instruments. This work aims to develop novel miRNA technologies which will address these above problems. Bioluminescent labels are promising alternatives to current methods of miRNA detection. Bioluminescent labels are relatively small, similar in size to fluorescent proteins, and they emit very intense signals upon binding to their substrate. Bioluminescent labels are advantageous to fluorescent labels in that they do not require an external excitation source, rather, the excitation energy is supplied through a biochemical reaction. Therefore, background signal due to excitation is eliminated. They also have the advantage of being produced in large amounts through bacterial expression. Four miRNA detection methods are presented which utilize luminescence-based methods. Three employ Renilla luciferase, a bioluminescent protein, and one is based on fluorescence. The presented methods are capable of detecting miRNA from the picomole (nanomolar) level down to the femtomole (picomolar) level. These methods are rapid, sensitive, simple, and quantitative, can be employed in complex matrices, and do not require expensive instruments. All methods are hybridization-based and do not require amplification steps.

<p dir="ltr">Nucleic acid testing has become a prominent method for rapid microbial detection. Unlike polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP) is a simple method of nucleic acid amplification where the reaction can be performed at a constant temperature and the output provided in a colorimetric format. A transparent water bath heater is a desirable instrument to perform the heating and observe the visual results of nucleic acid amplification. However, existing methods of heating the water are not convenient for loading and unloading the nucleic acid samples. Here, we developed a field-deployable water bath heating device—an isothermal heater called IsoHeat for short–which is solely dedicated to performing LAMP reactions and can heat the water up to 85 °C (if needed). Using 3D-printing and LASER-cutting technology, we fabricated different parts of the device and mechanically assembled the parts to develop the entire device. Users can commence the heating by pressing the start button on the screen after entering the target temperature. Subsequently, the device heats up the water bath and maintains the target temperature through a PID algorithm-based control system. We demonstrate that IsoHeat can operate in environmental temperatures ranging from 5-33 °C and it can conduct LAMP reactions in a liquid format as well as in paper-based devices. IsoHeat is more efficient and user-friendly compared to a commercially available immersion-heating device, which is often used to perform LAMP reactions. This newly developed device would be helpful to detect pathogens conveniently in the field (e.g., at the point-of-care for human applications, on farms for plant and animal applications, and in production facilities for food safety applications).</p>

MicroRNAs are a class of small non-coding RNAs involved in post-transcriptional regulation. Their role in almost all processes of the cell, make microRNAs ubiquitary players of cell development, growth, differentiation, cell to cell communication and cell death. Thus, cells’ physiological or pathological conditions are reflected by variations in the levels of expression of microRNAs, enabling them to be used as biomarkers of such states. In the past decade, there has been an exponential increase of studies using microRNAs as potential biomarkers for cancer, neurodegenerative diseases, inflammation and cardiac diseases, from tissues and liquid biopsies. However, none of them has reached the clinics yet, due to inconsistency of results through the literature and lack of assay standardization and reproducibility. Technological limitations of microRNAs detection have been, to date, the biggest challenge for using these molecules in clinical settings. In fact, although microarrays, RT-qPCR and RNA-seq are well-established technologies, they all require complex procedures and trained personnel, for performing RNA extraction, labelling of the target and PCR amplification. All these steps introduce variability and, in addition, since no universally standardized protocol – from sample extraction to analyte detection - has been produced yet, methodological procedures are difficult to reproduce. For this reason, we developed a new platform for the rapid detection of microRNAs in biofluids composed of an innovative silicon-photomultiplier (SiPM) based detector and a new chemistry for nucleic acid testing (Chem-NAT). Chem-NAT exploits a dynamic labelling chemistry which allows the sensitive detection of nucleic acids till single base level. On the other hand, SiPM-based device, compared to normal vacuum photomultipliers, grants miniaturization and higher capacity of fitting in a bench-top solution for clinical settings, among other advantages. The new platform – ODG – has been validated for the direct detection – neither RNA extraction nor PCR amplification needed - of microRNA-21 in plasma of lung cancer patients. In this work, we also explored the use of microRNAs as biomarkers in metastatic castration resistant prostate cancer (mCRPC). We collected plasma samples from mCRPC patients before and after abiraterone acetate treatment – androgen deprivation type of drug – and performed a miRnome analysis for discovering microRNAs predicting the efficacy of the drug. We chose miR-103a-3p and miR-378a-5p and we validated them via TaqMan RT-qPCR. We discovered that the ratio between the two microRNAs is able to predict the efficacy of abiraterone acetate and follow the responsiveness in time. In liquid biopsies, extracellular vesicles are getting increasing importance for diagnostic and prognostic purposes. Therefore, in this work we also explored the expression of some microRNAs in extracellular vesicles from plasma, isolated via nickel-based method. We discovered that microRNA-21 and microRNA-223 are not enriched in vesicles from healthy individuals.