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1. Ultrashort electron probe opportunities

   https://doi.org/10.1038/s41566-020-0613-1  

   Musumeci, Pietro (April 2020, Nature Photonics)
2. Vinculin tension probe in neurons

   https://doi.org/10.1117/12.2578501  

   Ayad, Marina A.; Mahon, Timothy; Sumetsky, Daniel; Cararo-Lopes, Marina M.; Firestein, Bonnie L.; Boustany, Nada N. (March 2021, Optical Techniques in Neurosurgery, Neurophotonics, and Optogenetics)

   Yang, Victor X.; Kainerstorfer, Jana M.; Luo, Qingming; Ding, Jun; Fu, Ling; Mohanty, Samarendra K.; Roe, Anna W.; Shoham, Shy (Ed.)

   Vinculin is a known key regulator of focal adhesions; it undergoes tension in the locations of attachment to the extracellular matrix. In this study, we explore the use of a vinculin tension FRET probe to investigate vinculin tension within neurons. A critical component of neuronal growth is migration, which is dependent on the mechanical cues between the cells and the extracellular matrix. An understanding of tension variation within the neuron may help us understand mechanisms of neurogenesis. To study these forces, we use a previously developed molecular tension sensor, which consists of an elastic linker, TSMod, a 40-amino-acid-long peptide inserted between teal fluorescent protein (mTFP1) and mVenus. The vinculin tension sensor, VinTS, consists of TSMod embedded between the Vinculin head and tail. When under tension, VinTS will exhibit a lower fluorescence resonance energy transfer (FRET) efficiency between mTFP1 and mVenus. Cortical neurons were isolated from embryonic rat brains and cultured on glass coverslips coated with poly-D-lysine and laminin. The neurons were transfected with TSMod (the unloaded tension sensor) or VinTS. Neurons expressing TSMod are used as the experiment’s control group since TSMod on its own is not affected by vinculin tension. The mean FRET efficiency of 171 TSMod and 127 VinTS expressing neurons was 27.08 ± 4.98%, and 22.86 ± 3.98%, respectively. The FRET efficiency of VinTS was significantly lower than that of TSMod (p = 6.6e15 by Welch’s t-test). These results support the feasibility of using the VinTS probe in neurons and provide a first assessment of VinTS FRET efficiency in neurons. The lower FRET efficiency of VinTS compared with TSMod suggests that VinTS may be under tension in neurons. However, additional studies are required to further characterize these results. 

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3. Local Crowd, Local Probe: Strengths and Drawbacks of Azidohomoalanine as a Site-Specific Crowding Probe

   https://doi.org/10.1021/acs.jpcb.4c00712  

   Shirley, Joseph C; Baiz, Carlos R (June 2024, The Journal of Physical Chemistry B)

   Every residue on a protein can be characterized by its interaction with water, in lack or in excess, as water is the matrix of biological systems. Infrared spectroscopy and the implementation of local azidohomoalanine (AHA) probes allow us to move beyond an ensemble or surface-driven conceptualization of water behavior and toward a granular, site-specific picture. In this paper, we examined the role of crowding in modulating both global and local behavior on the β-hairpin, TrpZip2 using a combination of Fourier-transform infrared spectroscopy (FTIR) spectroscopy, two-dimensional infrared (2D IR) spectroscopy, and molecular dynamics simulations. We found that, at the amino acid level, crowding drove dehydration of both sheet and turn peptide sites as well as free AHA. However, the subpicosecond dynamics showed highly individualized responses based on the local environment. Interestingly, while steady-state FTIR measurements revealed similar responses at the amino-acid level to hard versus soft crowding (dehydration), we found that PEG and glucose had opposite stabilizing and destabilizing effects on the protein secondary structure, emphasizing an important distinction in understanding the impact of crowding on protein structure as well as the role of crowding across length scales. 

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4. Pulsed Force Kelvin Probe Force Microscopy

   https://doi.org/10.1021/acsnano.0c00767  

   Jakob, Devon S.; Wang, Haomin; Xu, Xiaoji G. (April 2020, ACS Nano)

   null (Ed.)
5. Single optical fiber photoacoustic sensing probe

   https://doi.org/10.1117/12.2508008  

   Ustun, Arif Kivanc; Zou, Jun (February 2019, Proceedings of SPIE)