Small footprint optoelectrodes using ring resonators for passive light localization

The combination of electrophysiology and optogenetics enables the exploration of how the brain operates down to a single neuron and its network activity. Neural probes are in vivo invasive devices that integrate sensors and stimulation sites to record and manipulate neuronal activity with high spatiotemporal resolution. State-of-the-art probes are limited by tradeoffs involving their lateral dimension, number of sensors, and ability to access independent stimulation sites. Here, we realize a highly scalable probe that features three-dimensional integration of small-footprint arrays of sensors and nanophotonic circuits to scale the density of sensors per cross-section by one order of magnitude with respect to state-of-the-art devices. For the first time, we overcome the spatial limit of the nanophotonic circuit by coupling only one waveguide to numerous optical ring resonators as passive nanophotonic switches. With this strategy, we achieve accurate on-demand light localization while avoiding spatially demanding bundles of waveguides and demonstrate the feasibility with a proof-of-concept device and its scalability towards high-resolution and low-damage neural optoelectrodes.

Optical Ring Resonators (ORR) Minimalisasi Rugi Daya Menggunakan Metode SA Dan PSO

Penyelesaian permasalahan yang terjadi pada industri penerbangan ataupun transfer data dapat diselesaikan dengan berbagai aplikasi teknik. Beberapa metode telah dikembangkan untuk menyelesaikan sistem persamaan ini dan metode Simulated Annealing (SA) merupakan salah satu metode yang dapat digunakan untuk menyelesaikan persamaan ini. Namun, metode ini memerlukan waktu yang lama untuk mendapatkan nilai optimum karena sistemnya akan terus mencari nilai global minimum tanpa memperhatikan jumlah iterasi yang telah dilakukan. Pada makalah ini, dibuktikan bahwa pada permasalahan ini untuk mendapatkan nilai global minimum dari daya yang diinginkan, metode Partical Swarm Optimization (PSO) lebih efektif dan efisien daripada metode SA. Hal ini karena PSO lebih cepat menemukan nilai global minimum serta hasil dari setiap iterasi yang dilakukan cenderung stabil daripada metode SA. Dari lima sampel yang dilakukan dengan metode PSO, nilai global minimum yang didapatkan lebih baik dengan nilai yang besar dan waktu yang lebih cepat daripada metode SA.

Rapid Drop-Test for Lectin Binding with Glycopolymer-Coated Optical Ring Resonators

We fabricated a simple sensor system for qualitative analysis of glycan-mediated interactions. Our main aim was to establish a ronbbust system that allowes drop-tests without complex fluidics. The test system should be usable in routine analytics in the future and bear sufficient sensitivity to detect binding events in the nanomolar range. For this, we employed optical ring resonators and coated them with high avidity glycopolymers based on N-acetylglucosamine (GlcNAc). These hydrophilic polymers are also very feasible in preventing unspecific protein adsorption. Drop-on binding studies with suitable lectins showed that glycopolymers were specifically recognized by a lectin with GlcNAc-specificity and prevented unspecific protein interactions very well. The system could be elaborated in the future for detection of glycan-mediated interactions in the biomedical field and is promising in means of multiplexed analysis and usage in routine analysis.