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We fabricated a novel single molecule nanosensor by integrating a solid-state nanopore and a double nanohole nanoaperture. The nanosensor employs Self-Induced Back-Action (SIBA) for optical trapping and enables SIBA-Actuated Nanopore Electrophoresis (SANE) for concurrent acquisition of bimodal optical and electrical signatures of molecular interactions. This work describes how to fabricate and use the SANE sensor to quantify antibody-ligand interactions. We describe how to analyze the bimodal optical-electrical data to improve upon the discrimination of antibody and ligand versus bound complex compared to electrical measurements alone. Example results for specific interaction detection are described for T-cell receptor-like antibodies (TCRmAbs) engineered to target peptide-presenting Major Histocompatibility Complex (pMHC) ligands, representing a model of target ligands presented on the surface of cancer cells. We also describe how to analyze the bimodal optical-electrical data to discriminate between specific and non-specific interactions between antibodies and ligands. Example results for non-specific interactions are shown for cancer-irrelevant TCRmAbs targeting the same pMHCs, as a control. These example results demonstrate the utility of the SANE sensor as a potential screening tool for ligand targets in cancer immunotherapy, though we believe that its potential uses are much broader.

A plasmonic nanopore sensor enabling detection of bimodal optical and electrical molecular signatures was fabricated and tested for its ability to characterize low affinity ligand-receptor interactions. This plasmonic nanosensor uses self-induced back-action (SIBA) for optical trapping to enable SIBA-actuated nanopore electrophoresis (SANE) through a nanopore located immediately below the optical trap volume. A natural killer (NK) cell inhibitory receptor heterodimer molecule CD94/NKG2A was synthesized to target a specific peptide-presenting Qa-1b Qdm ligand as a simplified model of low-affinity interactions between immune cells and peptide-presenting cancer cells that occurs during cancer immunotherapy. A cancer-irrelevant Qa-1b GroEL ligand was also targeted by the same receptor as a control experiment to test for non-specific binding. The analysis of different pairs of bimodal SANE sensor signatures enabled discrimination of ligand, receptor and their complexes and enabled differentiating between specific and non-specific ligand interactions. We were able to detect ligand-receptor complex binding at concentrations over 500 times lower than the free solution equilibrium binding constant (K D ). Additionally, SANE sensor measurements enabled estimation of the fast dissociation rate (k off) for this low-affinity specific ligand-receptor system, previously shown to be challenging to quantify with commercial technologies. The k off value of targeted peptide-presenting ligands is known to correlate with the subsequent activation of immune cells in vivo, suggesting the potential utility of the SANE senor as a screening tool in cancer immunotherapy.

A plasmonic nanopore sensor enabling detection of bimodal optical and electrical molecular signatures was fabricated and tested for its ability to characterize low affinity ligand-receptor interactions. This plasmonic nanosensor uses a Self- Induced Back-Action (SIBA) mechanism for optical trapping to enable SIBA-Actuated Nanopore Electrophoresis (SANE) sensing through a nanopore located immediately below the optical trap volume. The ligand-receptor model consisted of a Natural Killer (NK) cell inhibitory receptor heterodimer molecule CD94/NKG2A that was synthesized to target a specific peptide-presenting Qa-1b Qdm ligand. The latter interaction pair was used as a simplified model of lowaffinity interactions between immune cells and peptide-presenting cancer cells that occur during cancer immunotherapy. A cancer-irrelevant GroEL ligand was also targeted by the same receptor in control experiments to test for non-specific interactions. Although the analysis of different pairs of bimodal SANE sensor signatures enabled some level of discrimination between specific and non-specific interactions the separation was not complete, which suggested the need for multi-dimensional data analyses in future work. Nevertheless, the SANE sensor showed ability to quantify the fast dissociation rate (koff) in this low-affinity model system that was previously shown to be challenging to quantify with commercial technologies. The koff value of targeted peptide-presenting ligands is known to correlate with the subsequent activation of immune cells in vivo, suggesting the potential utility of the SANE sensor as a screening tool in cancer immunotherapy.

How ideas develop and evolve is a topic of interest for educators. By understanding this process, designers and educators are better able to support and guide collaborative learning activities. This paper presents an application of our Lifespan of an Idea framework to measure engagement patterns among individuals in communal socio-technical spaces like Twitter. We correlated engagement with social participation, enabling the process of idea expression, spread, and evolution. Social participation leads to transmission of ideas from one individual to another and can be gauged in the same way as evaluating diseases. The temporal dynamics of the social participation can be modeled through the lens of epidemiological modeling. To test the plausibility of this framework, we investigated social participation on Twitter using the tweet posting patterns of individuals in three academic conferences and one long term chat space. We used a basic SIR epidemiological model, where the rate parameters were estimated through Euler's solutions to SIR model and non-linear least squares optimization technique. We discuss the differences in the social participation among individuals in these spaces based on their transition behavior into different categories of the SIR model. We also made inferences on how the total lifetime of these different twitter spaces affects the engagement among individuals. We conclude by discussing implications of this study and planned future research of refining the Lifespan of an Idea Framework.

Recent advances in plasmonic nanopore technologies have enabled the use of concurrently acquired bimodal optical-electrical data for improved quantification of molecular interactions. This work presents the use of a new plasmonic nanosensor employing self-induced back-action (SIBA) for optical trapping to enable SIBA-actuated nanopore electrophoresis (SANE) for quantifying antibody-ligand interactions. T-cell receptor-like antibodies (TCRmAbs) engineered to target peptide-presenting major histocompatibility complex (pMHC) ligands, representing a model of target ligands presented on the surface of cancer cells, were used to test the SANE sensor's ability to identify specific antibody-ligand binding. Cancer-irrelevant TCRmAbs targeting the same pMHCs were also tested as a control. It was found that the sensor could provide bimodal molecular signatures that could differentiate between antibody, ligand and the complexes that they formed, as well as distinguish between specific and non-specific interactions. Furthermore, the results suggested an interesting phenomenon of increased antibody-ligand complex bound fraction detected by the SANE sensor compared to that expected for corresponding bulk solution concentrations. A possible physical mechanism and potential advantages for the sensor's ability to augment complex formation near its active sensing volume at concentrations lower than the free solution equilibrium binding constant (K D ) are discussed.

We present a novel method to trap nanoparticles in double nanohole (DNH) nanoapertures integrated on top of solid-state nanopores (ssNP). The nanoparticles were propelled by an electrophoretic force from the cis towards the trans side of the nanopore but were trapped in the process when they reached the vicinity of the DNH-ssNP interface. The self-induced back action (SIBA) plasmonic force existing between the tips of the DNH opposed the electrophoretic force and enabled simultaneous optical and electrical sensing of a single nanoparticle for seconds. The novel SIBA actuated nanopore electrophoresis (SANE) sensor was fabricated using two-beam GFIS FIB. Firstly, Ne FIB milling was used to create the DNH features and was combined with end pointing to stop milling at the metal-dielectric interface. Subsequently, He FIB was used to drill a 25 nm nanopore through the center of the DNH. Proof of principle experiments to demonstrate the potential utility of the SANE sensor were performed with 20 nm silica and Au nanoparticles. The addition of optical trapping to electrical sensing extended translocation times by four orders of magnitude. The extended electrical measurement times revealed newly observed high frequency charge transients that were attributed to bobbing of the nanoparticle driven by the competing optical and electrical forces. Frequency analysis of this bobbing behavior hinted at the possibility of distinguishing single from multi-particle trapping events. We also discuss how SANE sensor measurement characteristics differ between silica and Au nanoparticles due to differences in their physical properties and how to estimate the charge around a nanoparticle. These measurements show promise for the SANE sensor as an enabling tool for selective detection of biomolecules and quantification of their interactions.