Recent advancements in nanomechanical microcantilever biosensors open new possibilities for clinical applications, permitting precise analysis of molecular interactions. The technology enables tracking gene expression, molecular conformational changes, antibody binding and antibiotic resistance. In particular, hybridization of DNA or RNA extracted from biopsies and whole blood from patients has led to significant advancements in diagnostics of critical medical conditions, e.g., cancer, bacteraemia and sepsis, utilizing rapid, sensitive, and label-free detection. Direct diagnosis from patient samples is a decisive advantage over competitive methods circumventing elaborate and time-consuming purification, amplification and cultivation procedures prior to analysis. Here, recent developments are presented from simple DNA hybridization of synthesized oligonucleotides to RNA material obtained from patients’ blood samples, highlighting technological advancements in diagnostic applications, such as detection of pathogens and disease biomarkers. We envisage our method to be a significant input to rapid, early and sensitive diagnosis directly from patients’ blood without requirements for amplification or cultivation. This would represent a paradigm shift in diagnostics, as no competing method currently exists.

Sepsis is a life-threatening condition mostly caused by a bacterial infection resulting in inflammatory reaction and organ dysfunction if not treated effectively. Rapid identification of the causing bacterial pathogen already in the early stage of bacteremia is therefore vital. Current technologies still rely on time-consuming procedures including bacterial culturing up to 72 h. Our approach is based on ultra-rapid and highly sensitive nanomechanical sensor arrays. In measurements we observe two clearly distinguishable distributions consisting of samples with bacteria and without bacteria respectively. Compressive surface stress indicates the presence of bacteria. For this proof-of-concept, we extracted total RNA from EDTA whole blood samples from patients with blood-culture-confirmed bacteremia, which is the reference standard in diagnostics. We determined the presence or absence of bacterial RNA in the sample through 16S-rRNA hybridization and species-specific probes using nanomechanical sensor arrays. Via both probes, we identified two clinically highly-relevant bacterial species i.e., Escherichia coli and Staphylococcus aureus down to an equivalent of 20 CFU per milliliter EDTA whole blood. The dynamic range of three orders of magnitude covers most clinical cases. We correctly identified all patient samples regarding the presence or absence of bacteria. We envision our technology as an important contribution to early and sensitive sepsis diagnosis directly from blood without requirement for cultivation. This would be a game changer in diagnostics, as no commercial PCR or POCT device currently exists who can do this.

The regulation of cell growth has fundamental physiological, biotechnological and medical implications. However, methods that can continuously monitor individual cells at sufficient mass and time resolution hardly exist. Particularly, detecting the mass of individual microbial cells, which are much smaller than mammalian cells, remains challenging. Here, we modify a previously described cell balance (‘picobalance’) to monitor the proliferation of single cells of the budding yeast, Saccharomyces cerevisiae , under culture conditions in real time. Combined with optical microscopy to monitor the yeast morphology and cell cycle phase, the picobalance approaches a total mass resolution of 0.45 pg. Our results show that single budding yeast cells (S/G2/M phase) increase total mass in multiple linear segments sequentially, switching their growth rates. The growth rates weakly correlate with the cell mass of the growth segments, and the duration of each growth segment correlates negatively with cell mass. We envision that our technology will be useful for direct, accurate monitoring of the growth of single cells throughout their cycle.

Scanning probe microscopy (SPM), a key invention in nanoscience, has by now been extended to a wide spectrum of basic and applied fields. Its application to basic science led to a paradigm shift in the understanding and perception of matter at its nanoscopic and even atomic levels. SPM uses a sharp tip to physically raster-scan samples and locally collect information from the surface. Various signals can be directly detected by SPM in real space with atomic or nanoscale resolution, which provides insights into the structural, electronic, vibrational, optical, magnetic, (bio)chemical and mechanical properties. This Primer introduces the key aspects and general features of SPM and SPM set-up and variations, with particular focus on scanning tunnelling microscopy and atomic force microscopy. We outline how to conduct SPM experiments, as well as data analysis of SPM imaging, spectroscopy and manipulation. Recent applications of SPM to physics, chemistry, materials science and biology are then highlighted, with representative examples. We outline issues with reproducibility, and standards on open data are discussed. This Primer also raises awareness of the ongoing challenges and possible ways to overcome these difficulties, followed by an outlook of future possible directions.

A search is conducted for a low-mass charged Higgs boson produced in a top quark decay and subsequently decaying into a charm and a strange quark. The data sample was recorded in proton-proton collisions at $\\sqrt{s}=$ 13 TeV by the CMS experiment at the LHC and corresponds to an integrated luminosity of 35.9 fb$^{-1}$. The search is performed in the process of top quark pair production, where one top quark decays to a bottom quark and a charged Higgs boson, and the other to a bottom quark and a W boson. With the W boson decaying to a charged lepton (electron or muon) and a neutrino, the final state comprises an isolated lepton, missing transverse momentum, and at least four jets, of which two are tagged as b jets. To enhance the search sensitivity, one of the jets originating from the charged Higgs boson is required to satisfy a charm tagging selection. No significant excess beyond standard model predictions is found in the dijet invariant mass distribution. An upper limit in the range 1.68-0.25% is set on the branching fraction of the top quark decay to the charged Higgs boson and bottom quark for a charged Higgs boson mass between 80 and 160 GeV.

Abstract The worldwide emergence of multidrug‐resistant (MDR) bacteria is associated with significant morbidity, mortality, and healthcare costs. Rapid and accurate diagnostic methods to detect antibiotic resistance are critical for antibiotic stewardship and infection control measurements. Here a cantilever nanosensor‐based diagnostic assay is shown to detect single nucleotide polymorphisms (SNPs) and genes associated with antibiotic resistance in Gram negative (Pseudomonas aeruginosa) and positive (Enterococcus faecium) bacteria, representing frequent causes for MDR infections. Highly specific RNA capture probes for SNPs (ampRD135G or ampRG154R) or resistance genes (vanA, vanB, and vanD) allow to detect the binding of bacterial RNA within less than 5 min. Serial dilutions of bacterial RNA indicate an unprecedented sensitivity of 10 fg µL−1 total RNA corresponding to less than ten bacterial cells for SNPs and 1 fg µL−1 total RNA for vanD detection equivalent to single bacterial cell sensitivity.

We describe a search for Z boson pair production in p (cid:1) p collisions at ffiffiffi s p ¼ 1 : 96 TeV with the D0 detector at the Fermilab Tevatron Collider using a data sample corresponding to an integrated luminosity of 2 : 7 fb (cid:1) 1 . Using the final state decay ZZ ! ‘ þ ‘ (cid:1) (cid:1) (cid:1) (cid:1) (where ‘ ¼ e or (cid:2) ) we find a signal with a 2.6 standard deviations significance (2.0 expected) corresponding to a cross section of (cid:3) ð p (cid:1) p ! ZZ þ X Þ ¼ 2 : 01 (cid:2) 0 : 93 ð stat Þ (cid:2) 0 : 29 ð sys Þ pb .

Mechanobiology emerges at the crossroads of medicine, biology, biophysics and engineering and describes how the responses of proteins, cells, tissues and organs to mechanical cues contribute to development, differentiation, physiology and disease. The grand challenge in mechanobiology is to quantify how biological systems sense, transduce, respond and apply mechanical signals. Over the past three decades, atomic force microscopy (AFM) has emerged as a key platform enabling the simultaneous morphological and mechanical characterization of living biological systems. In this Review, we survey the basic principles, advantages and limitations of the most common AFM modalities used to map the dynamic mechanical properties of complex biological samples to their morphology. We discuss how mechanical properties can be directly linked to function, which has remained a poorly addressed issue. We outline the potential of combining AFM with complementary techniques, including optical microscopy and spectroscopy of mechanosensitive fluorescent constructs, super-resolution microscopy, the patch clamp technique and the use of microstructured and fluidic devices to characterize the 3D distribution of mechanical responses within biological systems and to track their morphology and functional state. Mechanobiology describes how biological systems respond to mechanical stimuli. This Review surveys basic principles, advantages and limitations of applying and combining atomic force microscopy-based modalities with complementary techniques to characterize the morphology, mechanical properties and functional response of complex biological systems to mechanical cues.

Author(s): Khademhosseini, Ali; Chan, Warren WC; Chhowalla, Manish; Glotzer, Sharon C; Gogotsi, Yury; Hafner, Jason H; Hammond, Paula T; Hersam, Mark C; Javey, Ali; Kagan, Cherie R; Kotov, Nicholas A; Lee, Shuit-Tong; Li, Yan; Mohwald, Helmuth; Mulvaney, Paul A; Nel, Andre E; Parak, Wolfgang J; Penner, Reginald M; Rogach, Andrey L; Schaak, Raymond E; Stevens, Molly M; Wee, Andrew TS; Brinker, Jeffrey; Chen, Xiaoyuan; Chi, Lifeng; Crommie, Michael; Dekker, Cees; Farokhzad, Omid; Gerber, Christoph; Ginger, David S; Irvine, Darrell J; Kiessling, Laura L; Kostarelos, Kostas; Landes, Christy; Lee, Takhee; Leggett, Graham J; Liang, Xing-Jie; Liz-Marzan, Luis; Millstone, Jill; Odom, Teri W; Ozcan, Aydogan; Prato, Maurizio; Rao, CNR; Sailor, Michael J; Weiss, Emily; Weiss, Paul S

Atomic force microscopy (AFM) is a powerful, multifunctional imaging platform that allows biological samples, from single molecules to living cells, to be visualized and manipulated. Soon after the instrument was invented, it was recognized that in order to maximize the opportunities of AFM imaging in biology, various technological developments would be required to address certain limitations of the method. This has led to the creation of a range of new imaging modes, which continue to push the capabilities of the technique today. Here, we review the basic principles, advantages and limitations of the most common AFM bioimaging modes, including the popular contact and dynamic modes, as well as recently developed modes such as multiparametric, molecular recognition, multifrequency and high-speed imaging. For each of these modes, we discuss recent experiments that highlight their unique capabilities.

A picobalance consisting of an optically excited microcantilever has been developed and used to measure the masses of individual healthy and virus-infected cells at high temporal and mass resolutions in culture conditions. This paper reports a method to measure the mass of adherent cells in culture conditions with millisecond time resolution and picogram mass sensitivity. The approach uses a microcantilever which is optically excited at one end to generate tiny oscillations. When a cell adheres to the opposite end of the cantilever the fluctuations shift and these shifts are read by an infrared laser. The researchers offer some first attempts to link these fluctuations to specific cellular functions. For example, they connected the observed mass fluctuations of the cells throughout the cell cycle to ATP synthesis and water transport via perturbation of the cells under analysis. The technique also identified an arrest in cell growth when a cell was infected with the vaccinia virus, although the rapid fluctuations continued until cell death. The regulation of size, volume and mass in living cells is physiologically important, and dysregulation of these parameters gives rise to many diseases1. Cell mass is largely determined by the amount of water, proteins, lipids, carbohydrates and nucleic acids present in a cell, and is tightly linked to metabolism, proliferation2 and gene expression3. Technologies have emerged in recent years that make it possible to track the masses of single suspended cells4,5 and adherent cells6,7,8. However, it has not been possible to track individual adherent cells in physiological conditions at the mass and time resolutions required to observe fast cellular dynamics. Here we introduce a cell balance (a ‘picobalance’), based on an optically excited microresonator, that measures the total mass of single or multiple adherent cells in culture conditions over days with millisecond time resolution and picogram mass sensitivity. Using our technique, we observe that the mass of living mammalian cells fluctuates intrinsically by around one to four per cent over timescales of seconds throughout the cell cycle. Perturbation experiments link these mass fluctuations to the basic cellular processes of ATP synthesis and water transport. Furthermore, we show that growth and cell cycle progression are arrested in cells infected with vaccinia virus, but mass fluctuations continue until cell death. Our measurements suggest that all living cells show fast and subtle mass fluctuations throughout the cell cycle. As our cell balance is easy to handle and compatible with fluorescence microscopy, we anticipate that our approach will contribute to the understanding of cell mass regulation in various cell states and across timescales, which is important in areas including physiology, cancer research, stem-cell differentiation and drug discovery.

Atomic force microscopy (AFM)-based methods have matured into a powerful nanoscopic platform, enabling the characterization of a wide range of biological and synthetic biointerfaces ranging from tissues, cells, membranes, proteins, nucleic acids and functional materials. Although the unprecedented signal-to-noise ratio of AFM enables the imaging of biological interfaces from the cellular to the molecular scale, AFM-based force spectroscopy allows their mechanical, chemical, conductive or electrostatic, and biological properties to be probed. The combination of AFM-based imaging and spectroscopy structurally maps these properties and allows their 3D manipulation with molecular precision. In this Review, we survey basic and advanced AFM-related approaches and evaluate their unique advantages and limitations in imaging, sensing, parameterizing and designing biointerfaces. It is anticipated that in the next decade these AFM-related techniques will have a profound influence on the way researchers view, characterize and construct biointerfaces, thereby helping to solve and address fundamental challenges that cannot be addressed with other techniques.

For many diseases, where a particular organ is affected, chemical by-products can be found in the patient's exhaled breath. Breath analysis is often done using gas chromatography and mass spectrometry, but interpretation of results is difficult and time-consuming. We performed characterization of patients' exhaled breath samples by an electronic nose technique based on an array of nanomechanical membrane sensors. Each membrane is coated with a different thin polymer layer. By pumping the exhaled breath into a measurement chamber, volatile organic compounds present in patients' breath diffuse into the polymer layers and deform the membranes by changes in surface stress. The bending of the membranes is measured piezoresistively and the signals are converted into voltages. The sensor deflection pattern allows one to characterize the condition of the patient. In a clinical pilot study, we investigated breath samples from head and neck cancer patients and healthy control persons. Evaluation using principal component analysis (PCA) allowed a clear distinction between the two groups. As head and neck cancer can be completely removed by surgery, the breath of cured patients was investigated after surgery again and the results were similar to those of the healthy control group, indicating that surgery was successful.

Jet multiplicity distributions in top quark pair () events are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC using a data set corresponding to an integrated luminosity of 19.7. The measurement is performed in the dilepton decay channels (, , and ). The absolute and normalized differential cross sections for production are measured as a function of the jet multiplicity in the event for different jet transverse momentum thresholds and the kinematic properties of the leading additional jets. The differential and cross sections are presented for the first time as a function of the kinematic properties of the leading additional jets. Furthermore, the fraction of events without additional jets above a threshold is measured as a function of the transverse momenta of the leading additional jets and the scalar sum of the transverse momenta of all additional jets. The data are compared and found to be consistent with predictions from several perturbative quantum chromodynamics event generators and a next-to-leading order calculation.

According to the American skin cancer foundation, there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung, and colon each year, and malignant melanoma represents its deadliest form. About 50% of all cases are characterized by a particular mutation BRAF(V600E) in the BRAF (Rapid Acceleration of Fibrosarcoma gene B) gene. Recently developed highly specific drugs are able to fight BRAF(V600E) mutated tumors but require diagnostic tools for fast and reliable mutation detection to warrant treatment efficiency. We completed a preliminary clinical trial applying cantilever array sensors to demonstrate identification of a BRAF(V600E) single-point mutation using total RNA obtained from biopsies of metastatic melanoma of diverse sources (surgical material either frozen or fixated with formalin and embedded in paraffin). The method is faster than the standard Sanger or pyrosequencing methods and comparably sensitive as next-generation sequencing. Processing time from biopsy to diagnosis is below 1 day and does not require PCR amplification, sequencing, and labels.