scholarly journals Multimodal Gold Nanostars as SERS Tags for Optically-Driven Doxorubicin Release Study in Cancer Cells

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7272
Author(s):  
Luca Minati ◽  
Devid Maniglio ◽  
Filippo Benetti ◽  
Andrea Chiappini ◽  
Giorgio Speranza
Keyword(s):  
Laser Scanning ◽  
Close Contact ◽  
Gold Surface ◽  
Laser Scanning Confocal Microscopy ◽  
Living Cells ◽  
Sers Signal ◽  
Scanning Confocal Microscopy ◽  
Gold Nanostars ◽  
Real Time Analysis

Surface Enhanced Raman Scattering (SERS) active gold nanostars represent an opportunity in the field of bioimaging and drug delivery. The combination of gold surface chemical versatility with the possibility to tune the optical properties changing the nanoparticles shape constitutes a multimodal approach for the investigation of the behavior of these carriers inside living cells. In this work, SERS active star-shaped nanoparticles were functionalized with doxorubicin molecules and covered with immuno-mimetic thiolated polyethylene glycol (PEG). Doxorubicin-conjugate gold nanoparticles show an intense Raman enhancement, a good stability in physiological conditions, and a low cytotoxicity. The strong adsorption of the anticancer drug doxorubicin in close contact with the gold nanostars surface enables their use as SERS tag imaging probes in vivo. Upon laser irradiation of the nanoparticles, a strong SERS signal is generated by the doxorubicin molecules close to the nanostars surface, enabling the localization of the nanoparticles inside the cells. After long time irradiation, the SERS signal drops, indicating the thermally driven delivery of the drug inside the cell. Therefore, the combination of SERS and laser scanning confocal microscopy is a powerful technique for the real-time analysis of drug release in living cells.

scholarly journals Monitoring Tritrophic Biocontrol Interactions Between Bacillus spp., Fusarium oxysporum f. sp. cubense, Tropical Race 4, and Banana Plants in vivo Based on Fluorescent Transformation System

2021 ◽  
Vol 12 ◽  
Author(s):  
Ping He ◽  
Shu Li ◽  
Shengtao Xu ◽  
Huacai Fan ◽  
Yongfen Wang ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Fluorescent Protein ◽  
Laser Scanning Confocal Microscopy ◽  
Transformation System ◽  
Scanning Confocal Microscopy ◽  
Bacillus Spp ◽  
Green Fluorescent ◽  
Race 4

Bacillus spp. is effective biocontrol agents for Fusarium wilt of banana (FWB), tropical race 4 (TR4). This study explores the colonization by Bacillus subtilis, Bacillus velezensis, and Bacillus amyloliquefaciens of host banana plants and elucidates the mechanism of antagonistic TR4 biocontrol. The authors selected one B. subtilis strain, three B. velezensis strains, and three B. amyloliquefaciens strains that are proven to significantly inhibit TR4 in vitro, optimized the genetic transformation conditions and explored their colonization process in banana plants. The results showed that we successfully constructed an optimized fluorescent electro-transformation system (OD600 of bacteria concentration=0.7, plasmid concentration=50ng/μl, plasmid volume=2μl, transformation voltage=1.8kV, and transformation capacitance=400Ω) of TR4-inhibitory Bacillus spp. strains. The red fluorescent protein (RFP)-labeled strains were shown to have high stability with a plasmid-retention frequency above 98%, where bacterial growth rates and TR4 inhibition are unaffected by fluorescent plasmid insertion. In vivo colonizing observation by Laser Scanning Confocal Microscopy (LSCM) and Scanning Electron Microscopy (SEM) showed that Bacillus spp. can colonize the internal cells of banana plantlets roots. Further, fluorescent observation by LSCM showed these RFP-labeled bacteria exhibit chemotaxis (chemotaxis ratio was 1.85±0.04) toward green fluorescent protein (GFP)-labeled TR4 hyphae in banana plants. We conclude that B. subtilis, B. velezensis, and B. amyloliquefaciens can successfully colonize banana plants and interact with TR4. Monitoring its dynamic interaction with TR4 and its biocontrol mechanism is under further study.

Imaging Subcellular Changes in Living Mammalian Embryos Using 1047 Nm Two Photon Excitation Fluorescence Microscopy

1999 ◽  
Vol 5 (S2) ◽  
pp. 1060-1061
Author(s):  
J. M. Squirrell ◽  
D. L. Wokosin ◽  
B. D. Bavister ◽  
J. G. White
Keyword(s):  
Fluorescence Imaging ◽  
Laser Scanning ◽  
Prolonged Exposure ◽  
Laser Scanning Confocal Microscopy ◽  
Living Cells ◽  
Laser Scanning Microscopy ◽  
Scanning Confocal Microscopy ◽  
Two Photon ◽  
Photon Excitation ◽  
Mammalian Embryos

A major challenge for fluorescence imaging of living cells is maintaining viability during and following prolonged exposure to excitation illumination, especially when imaging over hours or even days, as when studying mammalian embryonic development. The use of specific fluorescently labeled components in living embryos promises to reveal the roles of organelles and molecules in a native and reproducible context. However, to gain a thorough understanding of dynamic biological systems, events of interest must be recorded as they occur, while limiting perturbations caused by the observation technique. Therefore, establishing long-term fluorescence imaging methods that maintain viability is critical for advancing our understanding of cell and developmental biology.One promising technique for imaging living cells is two photon laser scanning microscopy (TPLSM). The lower energy per photon and the restriction of fluorophore excitation to the imaged focal plane should reduce the total photodamage to thick specimens when compared to conventional laser scanning confocal microscopy (LSCM).

In Vivo Laser Scanning Confocal Microscopy of the Ocular Surface in Glaucoma

2014 ◽  
Vol 20 (3) ◽  
pp. 879-894 ◽  
Author(s):  
Leonardo Mastropasqua ◽  
Luca Agnifili ◽  
Rodolfo Mastropasqua ◽  
Vincenzo Fasanella ◽  
Mario Nubile ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Ocular Surface ◽  
Laser Scanning ◽  
Current Knowledge ◽  
Laser Scanning Confocal Microscopy ◽  
Cellular Level ◽  
Surgical Approaches ◽  
Imaging Method ◽  
Scanning Confocal Microscopy

AbstractOver the past decade, knowledge about the ocular surface in glaucoma has significantly increased through the use of in vivo laser scanning confocal microscopy (LSCM). This in vivo imaging method can show modifications at the cellular level induced by anti-glaucoma drugs on ocular surface structures and adnexa in the eye. High-quality images of the conjunctiva, cornea, limbus, meibomian glands, and lymphoid structures during therapy can be obtained. In addition, LSCM opened new fields of research on the patho-physiology of aqueous humor (AH) hydrodynamics in untreated, and in medically or surgically treated glaucomatous patients. In these conditions, an enhancement of the trans-scleral AH outflow contributed to clarification of the mechanism of action of different anti-glaucoma medications and surgical approaches. Finally, the use of LSCM represented a huge advance in evaluation of bleb functionality after filtration surgery, defining the hallmarks of AH filtration through the bleb-wall and distinguishing functional from nonfunctional blebs. Thus, signs seen with LSCM may anticipate clinical failure, guiding the clinician in planning the appropriate timing of the various steps in bleb management. In this review we summarize the current knowledge about in vivo LSCM of the ocular surface in glaucoma.

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