Hendrik Vondracek

Dr. Hendrik Vondracek

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
6 July 2023 in Advanced Science
Verified
Journal Article
Open access
MMMiriam Marchi
Miriam Marchi
EREdoardo Raciti
Edoardo Raciti
SGSai Manoj Gali
Sai Manoj Gali
FPFederica Piccirilli
Federica Piccirilli
HVHendrik Vondracek
Hendrik Vondracek
Paolo FornasieroPaolo Fornasiero
Paolo Fornasiero
The manipulation of carbon nitride (CN) structures is one main avenue to enhance the activity of CN‐based photocatalysts. Increasing the efficiency of photocatalytic heterogeneous materials is a critical step toward the realistic implementation of sustainable schemes for organic synthesis. However, limited knowledge of the structure/activity relationship in relation to subtle structural variations prevents a fully rational design of new photocatalytic materials, limiting practical applications. Here, the CN structure is engineered by means of a microwave treatment, and the structure of the material is shaped around its suitable functionality for Ni dual photocatalysis, with a resulting boosting of the reaction efficiency toward many CX (X = N, S, O) couplings. The combination of advanced characterization techniques and first‐principle simulations reveals that this enhanced reactivity is due to the formation of carbon vacancies that evolve into triazole and imine N species able to suitably bind Ni complexes and harness highly efficient dual catalysis. The cost‐effective microwave treatment proposed here appears as a versatile and sustainable approach to the design of CN‐based photocatalysts for a wide range of industrially relevant organic synthetic reactions.

29 April 2021 in Physical Chemistry Chemical Physics
Verified
Journal Article
Closed access
PDF file
IKInga Kolling
Inga Kolling
CHChristoph Hölzl
Christoph Hölzl
SISho Imoto
Sho Imoto
SASerena R. Alfarano
Serena R. Alfarano
HVHendrik Vondracek
Hendrik Vondracek
MHMartina Havenith
Martina Havenith
Trimethylamine N-oxide (TMAO) is a well known osmolyte in nature, which is used by deep sea fish to stabilize proteins against High Hydrostatic Pressure (HHP). We present a combined ab initio molecular dynamics, force field molecular dynamics, and THz absorption study of TMAO in water up to 12 kbar to decipher its solvation properties upon extreme compression. On the hydrophilic oxygen side of TMAO, AIMD simulations at 1 bar and 10 kbar predict a change of the coordination number from a dominating TMAO·(H2O)3 complex at ambient conditions towards an increased population of a TMAO·(H2O)4 complex at HHP conditions. This increase of the TMAO–oxygen coordination number goes in line with a weakening of the local hydrogen bond network, spectroscopic shifts and intensity changes of the corresponding intermolecular THz bands. Using a pressure-dependent HHP force field, FFMD simulations predict a significant increase of hydrophobic hydration from 1 bar up to 4–5 kbar, which levels off at higher pressures up to 10 kbar. THz spectroscopic data reveal two important pressure regimes with spectroscopic inflection points of the dominant intermolecular modes: The first regime (1.5–2 kbar) is barely recognizable in the simulation data. However, it relates well with the observation that the apparent molar volume of solvated TMAO is nearly constant in the biologically relevant pressure range up to 1 kbar as found in the deepest habitats on Earth in the ocean. The second inflection point around 4–5 kbar is related to the amount of hydrophobic hydration as predicted by the FFMD simulations. In particular, the blueshift of the intramolecular CNC bending mode of TMAO at about 390 cm−1 is the spectroscopic signature of increasingly pronounced pressure-induced changes in the solvation shell of TMAO. Thus, the CNC bend can serve as local pressure sensor in the multi-kbar pressure regime.

23 January 2026 in Science Advances
Verified
Journal Article
Open access
CLCorentin C. Loron
Corentin C. Loron
LCLaura M. Cooper
Laura M. Cooper
SMSean McMahon
Sean McMahon
SJSeán F. Jordan
Seán F. Jordan
AGAndrei V. Gromov
Andrei V. Gromov
AHAlexander J. Hetherington
Alexander J. Hetherington
Prototaxites was the first giant organism to live on the terrestrial surface, represented by columnar fossils of up to eight meters from the Early Devonian. However, its systematic affinity has been debated for over 165 years. There are now two remaining viable hypotheses: Prototaxites was either a fungus, or a member of an entirely extinct lineage. Here, we investigate the affinity of Prototaxites by contrasting its organization and molecular composition with that of Fungi. We report that fossils of Prototaxites taiti from the 407-million-year-old Rhynie chert were chemically distinct from contemporaneous Fungi and structurally distinct from all known Fungi. This finding casts doubt upon the fungal affinity of Prototaxites , instead suggesting that this enigmatic organism is best assigned to an entirely extinct eukaryotic lineage.

1 October 2016 in Review of Scientific Instruments
Verified
Journal Article
Closed access
PDF file
LKL. Knake
L. Knake
HVHendrik Vondracek
Hendrik Vondracek
MHMartina Havenith
Martina Havenith
We present a novel setup to investigate the low frequency (THz/FIR) spectra of an aqueous solution under high hydrostatic pressure (HHP). By integration of a diamond anvil cell into a THz Fourier transform spectrometer, we are able to record the absorption of bulk water in the pressure range from 1 bar to 10 kbar. The difference in intensity can directly be compared to the difference in extinction coefficients. The spectroscopic data reveal a blue shift of the H-bond stretch vibration at 180 cm−1, which is evidence of changes in the H-bond network dynamics.

23 December 2022 in Nanomaterials
Verified
Journal Article
Open access
PDF file
AAAhmed Alsadig Ahmed
Ahmed Alsadig Ahmed
BABehnaz Abbasgholi-NA
Behnaz Abbasgholi-NA
HVHendrik Vondracek
Hendrik Vondracek
BMBarbara Medagli
Barbara Medagli
SFSara Fortuna
Sara Fortuna
LCLoredana Casalis
Loredana Casalis
Herein, we report on a smart biosensing platform that exploits gold nanoparticles (AuNPs) functionalized through ssDNA self-assembled monolayers (SAM) and the DNA-directed immobilization (DDI) of DNA-protein conjugates; a novel, high-sensitivity optical characterization technique based on a miniaturized gel electrophoresis chip integrated with online thermal lens spectrometry (MGEC-TLS), for the high-sensitivity detection of antigen binding events. Specifically, we characterized the physicochemical properties of 20 nm AuNPs covered with mixed SAMs of thiolated single-stranded DNA and bio-repellent molecules, referred to as top-terminated oligo-ethylene glycol (TOEG6), demonstrating high colloidal stability, optimal binder surface density, and proper hybridization capacity. Further, to explore the design in the frame of cancer-associated antigen detection, complementary ssDNA fragments conjugated with a nanobody, called C8, were loaded on the particles and employed to detect the presence of the HER2-ECD antigen in liquid. At variance with conventional surface plasmon resonance detection, MGEC-TLS characterization confirmed the capability of the assay to titrate the HER2-ECD antigen down to concentrations of 440 ng/mL. The high versatility of the directed protein-DNA conjugates immobilization through DNA hybridization on plasmonic scaffolds and coupled with the high sensitivity of the MGEC-TLS detection qualifies the proposed assay as a potential, easily operated biosensing strategy for the fast and label-free detection of disease-relevant antigens.

19 August 2024 in Physical Chemistry Chemical Physics
Verified
Journal Article
Closed access
PDF file
Emiliano LaudadioEmiliano Laudadio
Emiliano Laudadio
FPFederica Piccirilli
Federica Piccirilli
HVHendrik Vondracek
Hendrik Vondracek
Giovanna MobbiliGiovanna Mobbili
Giovanna Mobbili
MSMarta Stefania Semrau
Marta Stefania Semrau
Cristina MinnelliCristina Minnelli
Cristina Minnelli
The integration of SEIRA spectroscopy with MD simulation reveals structural differences in the compactness and hydration of helical motifs between active and inactive EGFR conformations allowing to study the structural impacts of EGFR mutations.