In situ silver nanoparticle development for molecular-specific biological imaging via highly accessible microscopies
Dae-Hyeon Song
;
Chang Woo Song
;
Jinkyoung Chung
, et al.
Nanoscale Adv.,2023,5(6):1636-1650.
DOI:
10.1039/d2na00449f
PubMed ID:
36926569
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Abstract: In biological studies and diagnoses, brightfield (BF), fluorescence, and electron microscopy (EM) are used to image biomolecules inside cells. When compared, their relative advantages and disadvantages are obvious. BF microscopy is the most accessible of the three, but its resolution is limited to a few microns. EM provides a nanoscale resolution, but sample preparation is time-consuming. In this study, we present a new imaging technique, which we termed decoration microscopy (DecoM), and quantitative investigations to address the aforementioned issues in EM and BF microscopy. For molecular-specific EM imaging, DecoM labels proteins inside cells using antibodies bearing 1.4 nm gold nanoparticles (AuNPs) and grows silver layers on the AuNPs' surfaces. The cells are then dried without buffer exchange and imaged using scanning electron microscopy (SEM). Structures labeled with silver-grown AuNPs are clearly visible on SEM, even they are covered with lipid membranes. Using stochastic optical reconstruction microscopy, we show that the drying process causes negligible distortion of structures and that less structural deformation could be achieved through simple buffer exchange to hexamethyldisilazane. Using DecoM, we visualize the nanoscale alterations in microtubules by microtubule-severing proteins that cannot be observed with diffraction-limited fluorescence microscopy. We then combine DecoM with expansion microscopy to enable sub-micron resolution BF microscopy imaging. We first show that silver-grown AuNPs strongly absorb white light, and the structures labeled with them are clearly visible on BF microscopy. We then show that the application of AuNPs and silver development must follow expansion to visualize the labeled proteins clearly with sub-micron resolution.
Purchased from AmBeed:
7446-81-3
Strong, Chemically Stable, and Enzymatically On-Demand Detachable Hydrogel Adhesion Using Protein Crosslink
Lee, Wonseok
;
Heo, Eunseok
;
Koo, Hye Been
, et al.
Macromol. Rapid Comm.,2023,44(4):2200750.
DOI:
10.1002/marc.202200750
PubMed ID:
36484110
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Abstract: Achieving strong adhesion between hydrogels and diverse materials is greatly significant for emerging technologies yet remains challenging. Existing methods using non-covalent bonds have limited pH and ion stability, while those using covalent bonds typically lack on-demand detachment capability, limiting their applications. In this study, a general strategy of covalent bond-based and detachable adhesion by incorporating amine-rich proteins in various hydrogels and inducing the interfacial crosslinking of the hydrogels using a protein-crosslinking agent is demonstrated. The protein crosslink offers topol. adhesion and can reach a strong adhesion energy of ≈750 J m-2. The chem. of the adhesion is characterized and that the inclusion of proteins inside the hydrogels does not alter the hydrogels' properties is shown. The adhesion remains intact after treating the adhered hydrogels with various pH solutions and ions, even at an elevated temperature The detachment is triggered by treating proteinase solution at the bonding front, causing the digestion of proteins, thus breaking up the interfacial crosslink network. In addition, that this approach can be used to adhere hydrogels to diverse dry surfaces, including glass, elastomers and plastics, is shown. The stable chem. of protein crosslinks opens the door for various applications in a wide range of chem. environments.
Keywords:
covalent adhesion ;
detachable adhesion ;
hydrogels ;
otein crosslinks
Purchased from AmBeed:
7446-81-3
Fabrication of Heterogeneous Chemical Patterns on Stretchable Hydrogels Using Single-Photon Lithography
Haeseong Im
;
Eunseok Heo
;
Dae-Hyeon Song
, et al.
Soft Matter,2022,18(23):4402-4413.
DOI:
10.1039/D2SM00253A
PubMed ID:
35635476
More
Abstract: Curved hydrogel surfaces bearing chemical patterns are highly desirable in various applications, including artificial blood vessels, wearable electronics, and soft robotics. However, previous studies on the fabrication of chemical patterns on hydrogels employed two-photon lithography, which is still not widely accessible to most laboratories. This work demonstrates a new patterning technique for fabricating curved hydrogels with chemical patterns on their surfaces without two-photon microscopy. In this work, we show that exposing hydrogels in fluorophore solutions to single photons via confocal microscopy enables the patterning of fluorophores on hydrogels. By applying this technique to highly stretchable hydrogels, we demonstrate three applications: (1) improving pattern resolution by fabricating patterns on stretched hydrogels and then returning the hydrogels to their initial, unstretched length; (2) modifying the local stretchability of hydrogels at a microscale resolution; and (3) fabricating perfusable microchannels with chemical patterns by winding chemically patterned hydrogels around a template, embedding the hydrogels in a second hydrogel, and then removing the template. The patterning method demonstrated in this work may facilitate a better mimicking of the physicochemical properties of organs in tissue engineering and may be used to make hydrogel robots with specific chemical functionalities.
Purchased from AmBeed:
7446-81-3
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