Fluorescence intensity and lifetime imaging of free and micellar-encapsulated doxorubicin in living cells

Dai, Xiaowen; Yue, Zhilian; Eccleston, Mark E.; Swartling, Johannes; Slater, Nigel K.H.; Kaminski, Clemens F.

doi:10.1016/j.nano.2007.12.002

Cited by 131 publications

(126 citation statements)

References 25 publications

(17 reference statements)

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“…5(A-B) shows the difference in fluorescence lifetime for both free DOX and nanocomplexes prepared at varying w/w ratios at 0 hours. The free DOX exhibits a lifetime of 1 ns 46 and the nanocomplexes at 0 hours display a dominant longer lifetime verifying P(MAA-co-CMA)-DOX conjugation as shown by their position in the phasor plot. 49,50 The data indicated that with increasing P(MAA-co-CMA)-DOX nanocomplexation ratios from 125 : 1 to 1250 : 1 longer lifetimes were observed in the same region.…”

Section: Characterization Studies Of P(maa-co-cma)-dox Nanocomplexesmentioning

confidence: 98%

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

et al. 2015

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Previously synthesized poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA) copolymers were examined as potential drug delivery vehicles. P(MAA-co-CMA) copolymers were fluorescently labelled and imaged in SHEP and HepG2 cells. To understand their cell internalization pathway endocytic inhibition studies were conducted. It was concluded that P(MAA-co-CMA) are taken up by the cells via clathrin-independent endocytosis (CIE) (both caveolae mediated and cholesterol dependent endocytosis) mechanisms. The formation and characterization of P(MAA-co-CMA)-doxorubicin (DOX) nanocomplexes was investigated by fluorescence lifetime imaging microscopy (FLIM), UV-Visible spectroscopy (UV-Vis) and dynamic light scattering (DLS) studies. The toxicity screening between P(MAA-co-CMA)-DOX nanocomplexes (at varying w/w ratios) and free DOX, revealed nanocomplexes to exhibit higher cytotoxicity towards cancer cells in comparison to normal cells. FLIM and confocal microscopy were employed for investigating the time-dependent release of DOX in SHEP cells and the cellular uptake profile of P(MAAco-CMA)-DOX nanocomplexes in cancer and normal cell lines, respectively. The endocytic pathway of P(MAA-co-CMA)-DOX nanocomplexes were examined in SHEP and HepG2 cells via flow cytometry revealing the complexes to be internalized through both clathrin-dependent (CDE) and CIE mechanisms. The drug delivery profile, reported herein, illuminates the specific endocytic route and therapeutic efficiency of P(MAA-co-CMA)-DOX nanocomplexes strongly suggesting these particles to be promising candidates for in vivo applications.

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Section: Characterization Studies Of P(maa-co-cma)-dox Nanocomplexesmentioning

confidence: 98%

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

et al. 2015

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“…This is due to the difficulty associated with distinguishing between fluorescence due to the released drug and that from the encapsulated drug. Dai et al [24] showed for the first time that fluorescence lifetime imaging microscopy (FLIM) could be applied to measure drug delivery inside cells and permitted the local environment of the drug inside the cell to be probed. FLIM produces contrast images based upon the lifetime of the fluorophores.…”

Section: Introductionmentioning

confidence: 99%

Study of Intracellular Delivery of Doxorubicin from Poly(lactide‐co‐glycolide) Nanoparticles by Means of Fluorescence Lifetime Imaging and Confocal Raman Microscopy

Romero

Qiu

Murray

et al. 2013

Macromolecular Bioscience

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The intracellular delivery of Doxorubicin (Dox) from poly(lactide-co-glycolide) (PLGA) nanoparticles stabilised with bovine serum albumin, in HepG2 cells, is studied via flow cytometry, fluorescence lifetime imaging microscopy (FLIM), confocal Raman microscopy (CRM) and cell viability studies. Flow cytometry shows that the initial uptake of PLGA and Dox follow the same kinetics. However, following 8 h of incubation, the fluorescence intensity and cellular uptake of Dox decreases, while in the case of PLGA both parameters remain constant. FLIM shows the presence of a single-lifetime species, with a lifetime of 1.15 ns when measured inside the cells. Cell viability decreases by approximately 20% when incubated for 24 h with PLGA loaded with Dox, with a particle concentration of 100 µg · mL(-1). At the single-cell level, CRM shows changes in the bands from DNA and proteins in the cell nucleus when incubated with PLGA loaded with Dox.

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“…43 The resulting conjugated system of bonds in Dox tetracene structure with partially disrupted aromaticity causes typical Dox absorbance, with a maximum at approximately 480 nm, as well as its fluorescence, with emission maximum at approximately 600 nm. 44 Changes in optical properties of an encapsulated drug, both absorbance and fluorescence, can be caused by different amounts of prematurely released drug, changes in the molecular structure of the drug, or even the structure of the nanocarrier. Absorbance (Figure 2A and C) and fluorescence ( Figure 2B and D) of the encapsulated drug in nanocarriers prepared in water (Figure 2A and B) and PBS ( Figure 2C and D) were collected every week.…”

Section: Optical Properties Of Encapsulated and Prematurely Released Doxmentioning

confidence: 99%

Apoferritin as an ubiquitous nanocarrier with excellent shelf life

Dostálová¹,

Vašíčková²,

Hynek³

et al. 2017

IJN

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Due to many adverse effects of conventional chemotherapy, novel methods of targeting drugs to cancer cells are being investigated. Nanosize carriers are a suitable platform for this specific delivery. Herein, we evaluated the long-term stability of the naturally found protein nanocarrier apoferritin (Apo) with encapsulated doxorubicin (Dox). The encapsulation was performed using Apo’s ability to disassemble reversibly into its subunits at low pH (2.7) and reassemble in neutral pH (7.2), physically entrapping drug molecules in its cavity (creating ApoDox). In this study, ApoDox was prepared in water and phosphate-buffered saline and stored for 12 weeks in various conditions (−20°C, 4°C, 20°C, and 37°C in dark, and 4°C and 20°C under ambient light). During storage, a very low amount of prematurely released drug molecules were detected (maximum of 7.5% for ApoDox prepared in PBS and 4.4% for ApoDox prepared in water). Fourier-transform infrared spectra revealed no significant differences in any of the samples after storage. Most of the ApoDox prepared in phosphate-buffered saline and ApoDox prepared in water and stored at −20°C formed very large aggregates (up to 487% of original size). Only ApoDox prepared in water and stored at 4°C showed no significant increase in size or shape. Although this storage caused slower internalization to LNCaP prostate cancer cells, ApoDox (2.5 μM of Dox) still retained its ability to inhibit completely the growth of 1.5×10 4 LNCaP cells after 72 hours. ApoDox stored at 20°C and 37°C in water was not able to deliver Dox inside the nucleus, and thus did not inhibit the growth of the LNCaP cells. Overall, our study demonstrates that ApoDox has very good stability over the course of 12 weeks when stored properly (at 4°C), and is thus suitable for use as a nanocarrier in the specific delivery of anticancer drugs to patients.

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Fluorescence intensity and lifetime imaging of free and micellar-encapsulated doxorubicin in living cells

Cited by 131 publications

References 25 publications

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

The endocytic pathway and therapeutic efficiency of doxorubicin conjugated cholesterol-derived polymers

Study of Intracellular Delivery of Doxorubicin from Poly(lactide‐co‐glycolide) Nanoparticles by Means of Fluorescence Lifetime Imaging and Confocal Raman Microscopy

Apoferritin as an ubiquitous nanocarrier with excellent shelf life

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