Multifrequency Nanomechanical Mass Spectrometer Prototype for Measuring Viral Particles Using Optomechanical Disk Resonators

Nanomechanical mass spectrometry allows characterization of analytes with broad mass range, from small proteins to bacterial cells, and with unprecedented mass sensitivity. In this work, we show a novel multifrequency nanomechanical mass spectrometer prototype designed for focusing, guiding and soft-landing of nanoparticles and viral particles on a nanomechanical resonator surface placed in vacuum. The system is compatible with optomechanical disk resonators, with an integrated optomechanical transduction method, and with the laser beam deflection technique for the measurement of the vibrations of microcantilever resonators. The prototype allows the in-vacuum alignment of resonators thanks to a dedicated visualization system. Finally, in this work, we have demonstrated the detection of gold nanoparticles, polystyrene nanoparticles and phage G viruses with optomechanical disks and microcantilever resonators.Peer reviewe

Factors affecting Kleptoparasitism by gulls in a multi-species seabird colony

Kleptoparasitism is defined as the stealing by one animal of food that has been caught by another. It is a well-known foraging tactic used opportunistically by many seabirds. Our study describes qualitatively and quantitatively kleptoparasitism of gulls on terns and compares the effect of prey quality (prey type and size) and environmental conditions (tide, wind direction and intensity) triggering such behavior. The rate of kleptoparasitism by Kelp Gulls (Larus dominicanus) was higher on Royal (Thalasseus maximus) than on Cayenne Terns (T. sandvicensis eurygnatha). However, the percentage of successful attacks on both species was similar (∼42%). We used an information-theoretic approach to determine the relative importance of prey quality and environmental conditions in triggering kleptoparasitism. We found that more valuable prey triggered kleptoparasitism whereas the environmental conditions included in the models didn't affect the rate of such behavior significantly. Our study shows the importance of prey quality in triggering kleptoparasitism and how this behavior can remove an important portion of food brought to the tern colony.Fil: García, Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Vassallo, Aldo Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Interspecific kleptoparasitism by Brown-headed Gulls (Chroicocephalus maculipennis) on two hosts with different foraging strategies: A comparative approach

Kleptoparasitism is a well known foraging strategy used opportunistically by many seabirds. Our study compares the strategies performed by a facultative kleptoparasite species, the Brown-hooded Gull (Chroicocephalus maculipennis), associated with two hosts with different foraging strategies, the American Oystercatcher (Haematopus palliatus) and Red-gartered Coot (Fulica armillata). In total, 97% of the prey items stolen from Oystercatchers were the clam Tagelus plebeius, and all prey items stolen from Coots were the crab Cyrtograpsus angulatus. The attack rate by Gulls (number of kleptoparasitic attacks per unit time) did not differ significantly between Oystercatchers and Coots, but the success rate of attacks (successful kleptoparasitic attacks as a proportion of total attacks) was greater for attacks on Coots than on Oystercatchers. The mean rate of feeding (number of stolen items ingested per minute) by Brown-hooded Gulls did not differ with host. Gulls strongly selected large prey when stealing food. The comparison of net intake (costbenefit balance) for each kleptoparasitehost system showed that profitability was 3.5 times higher when kelptoparsitising Coots than when stealing from Oystercatchers. We suggest future work should study in more detail the costs and benefits for kleptoparasites with multiple hosts in similar systems elsewhere.Fil: García, Germán Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Vassallo, Aldo Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Super-twisting-based meal detector for type 1 diabetes management: Improvement and assessment in a real-life scenario

[EN] Background and objective: Hybrid automated insulin delivery systems rely on carbohydrate counting to improve postprandial control in type 1 diabetes. However, this is an extra burden on subjects, and it introduces a source of potential errors that could impact control performances. In fact, carbohydrates estimation is challenging, prone to errors, and it is known that subjects sometimes struggle to adhere to this requirement, forgetting to perform this task. A possible solution is the use of automated meal detection algorithms. In this work, we extended a super-twisting-based meal detector suggested in the literature and assessed it on real-life data. Methods: To reduce the false detections in the original meal detector, we implemented an implicit discretization of the super-twisting and replaced the Euler approximation of the glucose derivative with a Kalman filter. The modified meal detector is retrospectively evaluated in a challenging real-life dataset corresponding to a 2-week trial with 30 subjects using sensor-augmented pump control. The assessment includes an analysis of the nature and riskiness of false detections. Results: The proposed algorithm achieved a recall of 70 [13] % (median [interquartile range]), a precision of 73 [26] %, and had 1.4 [1.4] false positives-per-day. False positives were related to rising glucose conditions, whereas false negatives occurred after calibrations, missing samples, or hypoglycemia treatments. Conclusions: The proposed algorithm achieves encouraging performance. Although false positives and false negatives were not avoided, they are related to situations with a low risk of hypoglycemia and hyperglycemia, respectively.This work was supported by grant DPI2016-78831-C2-1-R funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe"; grant PID2019-107722RB-C21 funded by MCIN/AEI/10.13039/501100011033; the Generalitat Valenciana through FSE funds (grant number ACIF/2017/021); the Italian Ministry of Education, Universities and Research (MIUR) through the project "Learn4AP: Patient-Specific Models for an Adaptive, Fault Tolerant Artificial Pancreas"(SIR initiative, project ID: RBSI14JYM2); the MIUR under the initiative "Departments of Excellence"(Law 232/2016).Faccioli, S.; Sala-Mira, I.; Diez, J.; Facchinetti, A.; Sparacino, G.; Del Favero, S.; Bondía Company, J. (2022). Super-twisting-based meal detector for type 1 diabetes management: Improvement and assessment in a real-life scenario. Computer Methods and Programs in Biomedicine. 219:1-10. https://doi.org/10.1016/j.cmpb.2022.10673611021

Simultaneous optical and mechanical sensing based on nano-optomechanical disks

Resumen del trabajo presentado en la 12th International Conference on Metamaterials, Photonic Crystals and Plasmonics - META, celebrada en Torremolinos (España), del 19 al 22 de julio de 2022In this work, we demonstrate that by bringing together optical and mechanical resonances in single sensing platforms, their performances are significantly enhanced. In particular, we use nano-optomechanical disks, which simultaneously support high quality optical and mechanical modes. First, we apply the simultaneous or dual optical and mechanical sensing technique for monitoring environmental changes. Then, we employ it for detecting individual bacteria, accessing to its optical and mechanical properties. A variety of optical and mechanical resonators have been successfully employed in a diversity of sensing applications. Typically, optical resonators stand out for being extraordinary sensitive, while mechanical resonators are highly reliable. In this sense, optomechanical devices are unique platforms, since they support, at the same time, high quality optical and mechanical modes. Here we highlight the advantages of combining optical and mechanical resonances in a unique sensing platform, improving the sensor assets, together with its reliability and robustness. In particular, we apply nano-optomechanical disks fabricated out of gallium arsenide (Figure 1), which have already shown excellent capabilities when operating in liquids and for biosensing applications [1, 2]. We first apply them for monitoring environmental changes. Notably, the dual sensing approach allows decoupling relative humidity and temperature changes, reaching extraordinary precision, 0.01 % and 100 µK respectively (Figure 2). To further prove the capabilities of this novel method, we employ it for detecting individual bacteria (Figure 3). The technique allows to simultaneously access the bacterium optical and mechanical properties, such as its refractive index, absorption coefficient, mass, rigidity and viscosity [3].Work produced with the support of a 2021 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. The Foundation takes no responsibility for the opinions, statements and contents of this project, which are entirely the responsibility of its authors. This research is also funded by the Spanish Ministry of Science under the project MicroBIOMS, reference PID2019-109765RA-I00. E.G.S. acknowledges financial support by the Spanish Science and Innovation Ministry through the Ramón y Cajal grant RYC2019-026626-I

Optomechanical detection of single bacterium mechanical modes

Resumen del trabajo presentado en Bionanomechanics Conference, celebrada de forma virtual del 4 al 7 de mayo de 2021Mechanical modes of biological particles such as proteins, viruses and bacteria involve coherent structural vibrations at frequencies in the THz and GHz domains, which carry very valuable information on their mechanical properties and structure that play a pivotal role in many relevant biological processes. Here we demonstrate the detection of single bacterium mechanical modes in ambient conditions, by using ultra-high frequency optomechanical resonators. We harness a particular regime in the physics of mechanical resonator sensing, which emerge when the sensor and the analyte support mechanical modes at similar frequencies (Figure 1). We develop a general theoretical framework to describe the different regimes that can be found when an analyte adsorbs on a mechanical resonant sensor. Our model recovers the classical inertial mass sensing regime as a limit case of a more general problem, showing excellent agreement with numerical simulations and experiments, which enables retrieving the eigenfrequencies and mechanical loss of the bacterium modes from the detected collective modes. We apply our method to study the effect of hydration on the properties of a single bacterium. This work opens the door for a new class of vibrational spectrometry based on the use of high frequency mechanical resonators with the unique capability to obtain information on single bioentities [1].Peer reviewe

Optomechanical detection of single bacterium mechanical modes

Resumen del trabajo presentado en el 17th International Workshop on Nanomechanical Sensing, celebrado de forma híbrida (presencial-online) desde Calgary, Alberta (Canadá), del 15 al 18 de junio de 2021Mechanical modes of biological particles such as proteins, viruses and bacteria involve coherent structural vibrations at frequencies in the THz and GHz domains, which carry very valuable information on their mechanical properties and structure that play a pivotal role in many relevant biological processes. Here we demonstrate the detection of single bacterium mechanical modes in ambient conditions, by using ultra-high frequency optomechanical resonators. We harness a particular regime in the physics of mechanical resonator sensing, which emerge when the sensor and the analyte support mechanical modes at similar frequencies (Figure 1). We develop a general theoretical framework to describe the different regimes that can be found when an analyte adsorbs on a mechanical resonant sensor. Our model recovers the classical inertial mass sensing regime as a limit case of a more general problem, showing excellent agreement with numerical simulations and experiments, which enables retrieving the eigenfrequencies and mechanical loss of the bacterium modes from the detected collective modes. We apply our method to study the effect of hydration on the properties of a single bacterium. This work opens the door for a new class of vibrational spectrometry based on the use of high frequency mechanical resonators with the unique capability to obtain information on single bioentities [1].Peer reviewe

Optomechanical detection of vibration modes of single bacterium

Resumen del trabajo presentado en la Conferencia Española de Nanofotónica (CEN2021), celebrada de forma virtual del 20 al 22 de septiembre de 2021Vibration modes of biological particles such as proteins, viruses and bacteria involve coherent structural vibrations at frequencies in the THz and GHz domains. These vibration modes carry information on its structure and mechanical properties that play a pivotal role in many relevant biological processes. Despite the rapid advances of optical spectroscopy techniques, detection of vibration modes of single bioparticles has remained elusive. Here we harness a particular regime in the physics of mechanical resonator sensing that serves for detecting them. By depositing single bacterium on the surface of ultra-high frequency optomechanical disk resonators, we demonstrate that the vibration modes of the disk and bacterium hybridize when their associated frequencies are similar (Figure). A general theoretical framework is developed to describe the different regimes that can be found when an analyte adsorbs on a mechanical resonant sensor. The model recovers the classical inertial mass sensing regime as a limit case of a more general problem. Theory, numerical calculations and experiments show excellent agreement, allowing to retrieve the eigenfrequencies and mechanical loss of the bacterium vibration modes. Our method is applied for analysis of the effect of hydration on the vibrational properties of a single bacterium. This work opens the door for a new class of vibrational spectrometry based on the use of high frequency mechanical resonators with the unique capability to obtain information on single biological entitiesThis work was supported by the European Union’s Horizon 2020 under grants agreement no. 731868 – VIRUSCAN, 681275 – LIQUIDMASS- ERC- CoG-2015 and 770933-NOMLI-ERC-CoG 2017. E. Gil-Santos acknowledge financial support by the Spanish Science and Innovation Ministry through the projects PID2019-109765RA-I00 and RYC2019-026626-I

Optomechanical detection of single bacterium mechanical modes

Resumen del trabajo presentado en la 8th Multifrequency AFM Conferenced, celebrada en Madrid (España), del 27 al 30 de octubre de 2020Low-frequency phonon modes of biological particles such as proteins, viruses and bacteria involve coherent structural vibrations at frequencies in the THz and GHz domains. These vibration modes carry information on its structure and mechanical properties that play a pivotal role in many relevant biological processes. Despite the rapid advances of optical spectroscopy techniques, detection of low-frequency phonons of single bioparticles has remained elusive. Here we harness a particular regime in the physics of mechanical resonator sensing that serves for detecting them. By depositing single bacterium on the surface of ultra-high frequency optomechanical disk resonators in ambient conditions, we demonstrate that the vibration modes of the disk and bacterium hybridize when their associated frequencies are similar (Figure 1). A general theoretical framework is developed to describe the different regimes that can be found when an analyte adsorbs on a mechanical resonant sensor