Hatice Altug

Swiss Federal Institute of Technology in Lausanne | EPFL · Institute of Bioengineering

Chiral metasurfaces provide invaluable tools capable of controlling structured light required for biosensing, photochemistry, holography, and quantum photonics. Here we suggest and realize a universal strategy for controlling the chiral response of resonant metasurfaces via the interplay of meta-atom geometry and lattice arrangements within all fiv...

The Activin-A precursor dimer can be cleaved by furin, but how this proteolytic maturation is regulated in vivo and how it facilitates access to signaling receptors is unclear. Here, analysis in a syngeneic melanoma grafting model shows that without furin coexpression, Activin-A failed to accelerate tumor growth, correlating with failure of one or...

The demand for continuous monitoring of biochemical markers for diagnostic purposes is increasing as it overcomes the limitations of traditional intermittent measurements. This study introduces a method for long‐term, continuous plasmonic biosensing of oligonucleotides with high temporal resolution. Our method is based on a regeneration‐based rever...

Recent studies investigated the hydrolysis of Magnesium (Mg) thin films, highlighting their potential use in biodegradable devices. Quantitatively monitoring the degradation rate and morphological changes of Mg through optical methods and light‐delivery devices offers an innovative, contactless technique, independent of electrical wiring. This meth...

The demand for continuous monitoring of biochemical markers for diagnostic purposes is increasing as it overcomes the limitations of traditional intermittent measurements. This study introduces a method for long‐term, continuous plasmonic biosensing of oligonucleotides with high temporal resolution. Our method is based on a regeneration‐based rever...

Organoid tumor models have emerged as a powerful tool in the fields of biology and medicine as such 3D structures grown from tumor cells recapitulate better tumor characteristics, making these tumoroids unique for personalized cancer research. Assessment of their functional behavior, particularly protein secretion, is of significant importance to p...

Surface‐enhanced infrared absorption spectroscopy (SEIRA) has emerged as a powerful technique for ultrasensitive chemical‐specific analysis. SEIRA can be realized by employing metasurfaces that can enhance light‐matter interactions in the spectral bands of molecular vibrations. Increasing sample complexity emphasizes the need for metasurfaces that...

High‐index dielectric subwavelength structures and metasurfaces are capable of enhancing light‐matter interaction by orders of magnitude via geometry‐dependent optical resonances. This enhancement, however, comes with a fundamental limitation of a narrow spectral range of operation in the vicinity of one or few resonant frequencies. Here we tackle...

Chirality (C) is a fundamental property of objects, in terms of symmetry. It is extremely important to sense and distinguish chiral molecules in the fields of biochemistry, science, and medicine. Vibrational circular dichroism (VCD) spectroscopy, obtained from the differential absorption of left- and right- circularly polarized light (CPL) in the i...

Background CD4 T cells help coordinating adaptive immune responses. Increasing evidence shows that antigen-specific CD4 T cells are also key players in anti-tumor immunity. We and others recently reported on the frequent existence of fully active, tumor-specific CD4 T cells with cytolytic properties in cancer patients. However, the molecular determ...

High-index dielectric subwavelength structures and metasurfaces are capable of enhancing light-matter interaction by orders of magnitude via geometry-dependent optical resonances. This enhancement, however, comes with a fundamental limitation of a narrow spectral range of operation in the vicinity of one or few resonant frequencies. Here we tackle...

Many photonic and electronic molecular properties, as well as chemical and biochemical reactivities are controlled by fast intramolecular vibrational energy redistribution (IVR). This fundamental ultrafast process limits coherence time in applications from photochemistry to single quantum level control. While time-resolved multidimensional IR-spect...

Methods for the analysis of cell secretions at the single-cell level only provide semiquantitative endpoint readouts. Here we describe a microwell array for the real-time spatiotemporal monitoring of extracellular secretions from hundreds of single cells in parallel. The microwell array incorporates a gold substrate with arrays of nanometric holes...

We design high-Q metasurfaces with resonant wavelengths in mid-IR varying continuously along the sample. We demonstrate tunable rainbow generation of high harmonics as we vary the pump wavelength and the coordinate along the metasurface.

Infrared (IR) spectroscopy provides unique information on the composition and dynamics of biochemical systems by resolving the characteristic absorption fingerprints of their constituent molecules. Based on this inherent chemical specificity and the capability for label‐free, non‐invasive, and real‐time detection, IR spectroscopy approaches have un...

Nanophotonic devices, which control light in subwavelength volumes and enhance light–matter interactions, have opened up exciting prospects for biosensing. Numerous nanophotonic biosensors have emerged to address the limitations of the current bioanalytical methods in terms of sensitivity, throughput, ease-of-use and miniaturization. In this Review...

Proteins secreted by cells play significant roles in mediating many physiological, developmental, and pathological processes due to their functions in intra/intercellular communication and signaling. Conventional end-point methods are insufficient for understanding the temporal response in cell secretion process, which is often highly dynamic. Furt...

We report a high-throughput biosensing microarray platform integrating ultrasensitive nanoplasmonic substrate and microwell compartments for label-free and real-time secretome monitoring. Interleukin-2 from hundreds of single EL4 cells were measured and a statistical analysis was done.

We demonstrate free-standing metasurfaces made by a new wafer-scale and CMOS compatible nanofabrication method and produce nanostructures over large-area transparent oxide membranes. Applications include narrow-band spectral filtering, efficient light focusing, polarization control and optofluidic biosensors.

We propose all-dielectric metasurfaces integrated with a tilting stage capable of in-situ sensor characterization for imaging-based label-free optofluidic biosensing. Our technique removes the need for pre-characterized sensors and sophisticated spectroscopy instrumentations favorable for point-of-care platforms.

Low-dimensional van der Waals (vdW) materials can harness tightly confined polaritonic waves to deliver unique advantages for nanophotonic biosensing. The reduced dimensionality of vdW materials, as in the case of two-dimensional graphene, can greatly enhance plasmonic field confinement, boosting sensitivity and efficiency compared to conventional...

Metasufaces In article number 2102232, Hatice Altug and co-workers demonstrate a wafer-scale nanofabrication method for manufacturing highly efficient meta-optical elements and metasurface-based optofluidic biosensors. The demonstrated method enables low-cost infrared optical components and disposable sensor chips for medical diagnostics, and has t...

Metasurfaces have emerged as a breakthrough platform for manipulating light at the nanoscale and enabling on-demand optical functionalities for next-generation biosensing, imaging, and light-generating photonic devices. However, translating this technology to practical applications requires low-cost and high-throughput fabrication methods. Due to t...

Biosensors are indispensable tools for public, global, and personalized healthcare as they provide tests that can be used from early disease detection and treatment monitoring to preventing pandemics. We introduce single-wavelength imaging biosensors capable of reconstructing spectral shift information induced by biomarkers dynamically using an adv...

Metasurfaces have outstanding light‐manipulation capabilities at the nanoscale, which enables functions beyond that which is otherwise seen in nature. In article number 2006054, Hatice Altug and co‐workers augment highly sensitive, broadband mid‐IR metasurfaces with artificial intelligence to introduce a spectroscopic biosensor that enables label‐f...

Insights into the fascinating molecular world of biological processes are crucial for understanding diseases, developing diagnostics, and effective therapeutics. These processes are complex as they involve interactions between four major classes of biomolecules, i.e., proteins, nucleic acids, carbohydrates, and lipids, which makes it important to b...

CD4 T cells have been implicated in cancer immunity for their helper functions. Moreover, their direct cytotoxic potential has been shown in some patients with cancer. Here, by mining single-cell RNA-seq datasets, we identified CD4 T cell clusters displaying cytotoxic phenotypes in different human cancers, resembling CD8 T cell profiles. Using the...

We present optofluidic label-free biosensors leveraging high quality-factor resonances emanated from bound-states-in-the-continuum and novel data processing. The sensors are based on imaging and offer solutions to remove sophisticated spectroscopy instrumentations towards point-of-care applications.

We present device applications of all-dielectric mid-infrared metasurfaces ranging from label-free biosensing and high precision spectral filtering to optical wavefront and polarization control. Additionally, we experimentally demonstrate how the concept of static Huygens’ metasurfaces can be extended with phase change materials to obtain spatial a...

Hybrid metal-dielectric nanostructures have recently gained prominence because they combine strong field enhancement of plasmonic metals and the several low-loss radiation channels of dielectric resonators, which are qualities pertaining to the best of both worlds. In this work, an array of such hybrid nanoantennas is successfully fabricated over a...

Background CD4 T cells have been implicated in cancer immunity for their helper functions. However, their direct cytotoxic potential remains elusive in cancer patients. Here, we aimed at assessing the presence, rate and cytotoxic function of tumor-specific Th-CTX directly in cancer patients. Methods We capitalized on published single cell transcri...

Most present-day resonant systems, throughout physics and engineering, are characterized by a strict time-reversal symmetry between the rates of energy coupled in and out of the system, which leads to a trade-off between how long a wave can be stored in the system and the system's bandwidth. Any attempt to reduce the losses of the resonant system,...

In article number 1910259, Andreas Tittl, Hatice Altug, and co‐workers develop tunable metasurfaces consisting of hybrid germanium and Ge3Sb2Te6 disk meta‐units. Switching the Ge3Sb2Te6 between its structural states enables dynamic light phase control with high transmittance. The versatility of these metasurfaces is demonstrated by optically progra...

Low‐loss nanostructured dielectric metasurfaces have emerged as a breakthrough platform for ultrathin optics and cutting‐edge photonic applications, including beam shaping, focusing, and holography. However, the static nature of their constituent materials has traditionally limited them to fixed functionalities. Tunable all‐dielectric infrared Huyg...

The past two decades have witnessed the explosion of activities in the field of surface enhanced Raman spectroscopy (SERS). SERS platforms employ nano-structures that excite plasmonic modes with large local electromagnetic fields localized within small gap spaces between each constituting feature. Although the research-oriented SERS platforms yield...

In article number 1906108, Anna Fàbrega, Hatice Altug, and co‐workers present a portable optical biosensor based on nanoparticle‐enhanced digital plasmonic imaging to assist sepsis diagnosis, enabling rapid and sensitive detection of blood‐circulating disease biomarkers. The low‐cost device is tested with patient samples in a hospital and is shown...

Sepsis is a critical health threat, and its survival strictly depends on early diagnosis. A novel portable biosensor based on nanoparticle-enhanced digital plasmonic imaging is reported for rapid and sensitive detection of two sepsis-related biomarkers, procalcitonin and C-reactive protein directly from blood senrm.

New point‐of‐care diagnostic devices are urgently needed for rapid and accurate diagnosis, particularly in the management of life‐threatening infections and sepsis, where immediate treatment is key. Sepsis is a critical condition caused by systemic response to infection, with chances of survival drastically decreasing every hour. A novel portable b...

An invisibility cloak should completely hide an object from an observer, ideally across the visible spectrum and for all angles of incidence and polarizations of light, in three dimensions. However, until now, all such devices have been limited to either small bandwidths or have disregarded the phase of the impinging wave or worked only along speci...

A biosensor device including a metal layer, a transparent substrate layer, and a dielectric layer, wherein the metal layer includes a plurality of sub-wavelength apertures, and wherein the dielectric layer is located between the metal layer and the transparent substrate layer to form a spectrally isolated and well-defined optical transmission reson...

Nanophotonics excels at confining light into nanoscale optical mode volumes and generating dramatically enhanced light matter interactions. These unique aspects have been unveiling a plethora of fundamentally new optical phenomena, yet a critical issue ahead for nanophotonics is the development of novel devices and applications that can take advant...

Molecular spectroscopy provides unique information on the internal structure of biological materials by detecting the characteristic vibrational signatures of their constituent chemical bonds at infrared frequencies. Nanophotonic antennas and metasurfaces have driven this concept towards few‐molecule sensitivity by confining incident light into int...

Detection and differentiation of enantiomers in small quantities are crucially important in many scientific fields including biology, chemistry, and pharmacy. Chiral molecules manifest their handedness in their interaction with the chiral state of light (e.g., circularly polarized light), which is commonly leveraged in circular dichroism (CD) spect...

Metasurfaces based on resonant subwavelength photonic structures enable novel ways of wavefront control and light focusing, underpinning a new generation of flat-optics devices¹. Recently emerged all-dielectric asymmetric metasurfaces, composed of arrays of metaunits with broken in-plane inversion symmetry2–7, exhibit high-quality resonances origin...

Infrared spectroscopy resolves the structure of molecules by detecting their characteristic vibrational fingerprints. Subwavelength light confinement and nanophotonic enhancement have extended the scope of this technique for monolayer studies. However, current approaches still require complex spectroscopic equipment or tunable light sources. Here,...

Sepsis is a condition characterized by a severe stage of blood-infection often leading to tissue damage, organ failure and finally death. Fast diagnosis and identification of the sepsis stage (sepsis, severe sepsis or septic shock) is critical for the patient's evolution and could help in defining the most adequate treatment in order to reduce its...

Einblick in Materie durch Metaresonanzen: Die Metaoberflächen‐basierte Biospektroskopie hat sich als empfindliches Werkzeug zur Quantifizierung der Bestandteile biochemischer Systeme etabliert. Dieser Kurzaufsatz präsentiert verschiedene Metaresonatorgeometrien und die einzigartigen Möglichkeiten, die sie für molekulare Studien bieten. Ein Schwerpu...

Modern devices require the tuning of the size, shape and spatial arrangement of nano-objects and their assemblies with nanometre-scale precision, over large-area and sometimes soft substrates. Such stringent requirements are beyond the reach of conventional lithographic techniques or self-assembly approaches. Here, we show nanoscale control over th...

In the version of this Article originally published, the volume, article number and year of ref. 32 were incorrect; they should have read 31, 1802348 (2019). This has now been corrected.

Typical, reciprocal resonant systems are always limited to a time-bandwidth product of 1, causing a fundamental trade-off between long storage times and large acceptance bandwidths. A recent theory suggests that this limit may be arbitrarily overcome by breaking Lorentz reciprocity. We report an experimental realization of this concept using a time...

Typical, reciprocal resonant systems are always limited to a time-bandwidth product of 1, causing a fundamental trade-off between long storage times and large acceptance bandwidths. A recent theory suggests that this limit may be arbitrarily overcome by breaking Lorentz reciprocity. We report an experimental realization of this concept using a time...

In an effort to address the requirements of next-generation healthcare systems, including personalized medicine, point-of-care diagnostics, and global health surveillance, I will introduce imaging-based portable nanoplasmonic biosensors integrated with microfluidic systems for various bioanalytical applications.

We present a nanophotonic method capable of detecting mid-infrared molecular fingerprints without the need for spectrometry, frequency scanning, or moving mechanical parts. We leverage dielectric metasurfaces featuring ultra-sharp resonances each tuned to discrete frequencies, enabling us to sample molecular absorption signatures over the mid-IR sp...

We reveal that optical chirality at the nanoscale can be boosted dramatically by bound states in the continuum (BIC). We predict the enhancement of chiroptical signals from nanostructures supporting quasi-BICs in mid-IR with a record-high efficiency.

Mobile and affordable biosensors enabling detection of disease biomarkers from small sample volumes are essential for next-generation healthcare systems. Here, I will introduce ultrasensitive compact biosensors and label-free large-area biomolecule imagers based on nanophotonic metasurfaces.

We present an ultra-sensitive label-free point-of-care platform for potential early diagnosis of sepsis based on lens-free interferometric phase imaging and localized surface plasmon resonance.