26 research outputs found
Multifunctional Lactobionic Acid-Modified Dendrimers for Targeted Drug Delivery to Liver Cancer Cells: Investigating the Role Played by PEG Spacer
We
report the development of a lactobionic acid (LA)-modified multifunctional
dendrimer-based carrier system for targeted therapy of liver cancer
cells overexpressing asialoglycoprotein receptors. In this study,
generation 5 (G5) polyÂ(amidoamine) (PAMAM) dendrimers were sequentially
modified with fluorescein isothiocyanate (FI) and LA (or polyethylene
glycol (PEG)-linked LA, PEG-LA), followed by acetylation of the remaining
dendrimer terminal amines. The synthesized G5.NHAc-FI-LA or G5.NHAc-FI-PEG-LA
conjugates (NHAc denotes acetamide groups) were used to encapsulate
a model anticancer drug doxorubicin (DOX). We show that both conjugates
are able to encapsulate approximately 5.0 DOX molecules within each
dendrimer and the formed dendrimer/DOX complexes are stable under
different pH conditions and different aqueous media. The G5.NHAc-FI-PEG-LA
conjugate appears to have a better cytocompatibility, enables a slightly
faster DOX release rate, and displays better liver cancer cell targeting
ability than the G5.NHAc-FI-LA conjugate without PEG under similar
experimental conditions. Importantly, the developed G5.NHAc-FI-PEG-LA/DOX
complexes are able to specifically inhibit the growth of the target
cells with a better efficiency than the G5.NHAc-FI-LA/DOX complexes
at a relatively high DOX concentration. Our results suggest a key
role played by the PEG spacer that affords the dendrimer platform
with enhanced targeting and therapeutic efficacy of cancer cells.
The developed LA-modified multifunctional dendrimer conjugate with
a PEG spacer may be used as a delivery system for targeted liver cancer
therapy and offers new opportunities in the design of multifunctional
drug carriers for targeted cancer therapy applications
Acetylated Polyethylenimine-Entrapped Gold Nanoparticles Enable Negative Computed Tomography Imaging of Orthotopic Hepatic Carcinoma
Developing
an effective computed tomography (CT) contrast agent
is still a challenging task for precise diagnosis of hepatic carcinoma
(HCC). Here, we present the use of acetylated polyethylenimine (PEI)-entrapped
gold nanoparticles (Ac-PE-AuNPs) without antifouling modification
for negative CT imaging of HCC. PEI was first linked to fluorescein
isothiocyanate (FI) and then utilized as a vehicle for the entrapment
of AuNPs. The particles were then acetylated to reduce its positive
surface potential. The designed Ac-PE-AuNPs were characterized by
various techniques. We find that the Ac-PE-AuNPs with a uniform size
distribution (mean diameter = 2.3 nm) are colloidally stable and possess
low toxicity in the studied range of concentration. Owing to the fact
that the particles without additional antifouling modification were
mainly gathered in liver, the Ac-PE-AuNPs could greatly improve the
CT contrast enhancement of normal liver, whereas poor CT contrast
enhancement appeared in liver necrosis region caused by HCC. As a
result, HCC could be easily and precisely diagnosed. The designed
Ac-PE-AuNPs were demonstrated to have biocompatibility through in
vivo biodistribution and histological studies, hence holding an enormous
potential to be adopted as an effective negative CT contrast agent
for diagnosis of hepatoma carcinoma
Manganese Dioxide-Entrapping Dendrimers Co-Deliver Protein and Nucleotide for Magnetic Resonance Imaging-Guided Chemodynamic/Starvation/Immune Therapy of Tumors
Development
of a nanoscale drug delivery system that can simultaneously
exert efficient tumor therapeutic efficacy while creating the desired
antitumor immune responses is still challenging. Herein, we report
the use of a manganese dioxide (MnO2)-entrapping dendrimer
nanocarrier to codeliver glucose oxidase (GOx) and cyclic GMP-AMP
(cGAMP), an agonist of the stimulator of interferon genes (STING)
for improved tumor chemodynamic/starvation/immune therapy. Methoxy
poly(ethylene glycol) (mPEG)- and phenylboronic acid
(PBA)-modified generation 5 (G5) poly(amidoamine) dendrimers were
first synthesized and then entrapped with MnO2 nanoparticles
(NPs) to generate the hybrid MnO2@G5-mPEG–PBA (MGPP) NPs. The created MGPP NPs with an MnO2 core size of 2.8 nm display efficient glutathione depletion ability,
and a favorable Mn2+ release profile under a tumor microenvironment
mimetic condition to enable Fenton-like reaction and T1-weighted magnetic resonance (MR) imaging.
We show that the MGPP-mediated GOx delivery facilitates enhanced chemodynamic/starvation
therapy of cancer cells in vitro, and further codelivery of cGAMP
can effectively trigger immunogenic cell death (ICD) to strongly promote
the maturation of dendritic cells. In a bilateral mouse colorectal
tumor model, the dendrimer delivery nanosystem elicits a potent antitumor
performance with a strong abscopal effect, greatly improving the overall
mouse survival rate. Importantly, the dendrimer-mediated codelivery
not only allows the coordination of Mn2+ with GOx and cGAMP
for respective chemodynamic/starvation-triggered ICD and augmented
STING activation to boost systemic antitumor immune responses, but
also enables T1-weighted tumor MR imaging,
potentially serving as a promising nanoplatform for enhanced antitumor
therapy with desired immune responses
<sup>99m</sup>Tc-Labeled Multifunctional Low-Generation Dendrimer-Entrapped Gold Nanoparticles for Targeted SPECT/CT Dual-Mode Imaging of Tumors
Development
of cost-effective and highly efficient nanoprobes for
targeted tumor single-photon emission computed tomography (SPECT)/computed
tomography (CT) dual-mode imaging remains a challenging task. Here,
multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs)
modified with folic acid (FA) and labeled with <sup>99m</sup>Tc were
synthesized for targeted dual-mode SPECT/CT imaging of tumors. Generation
2 (G2) polyÂ(amidoamine) (PAMAM) dendrimers (G2-NH<sub>2</sub>) conjugated
with cyclic diethylenetriamine pentaacetic anhydride (cDTPAA) via
an amide linkage and FA via a spacer of polyethylene glycol (PEG)
were used for templated synthesis of Au core NPs, followed by labeling
of <sup>99m</sup>Tc via chelation. The thus created multifunctional
Au DENPs were well-characterized. It is shown that particles with
an average Au core diameter of 1.6 nm can be dispersed in water, display
stability under different conditions, and are cytocompatible in the
studied concentration range. Further results demonstrate that the
multifunctional nanoprobe is able to be utilized for targeted SPECT/CT
dual-mode imaging of cancer cells having FA receptor (FAR)-overexpression
in vitro and the established subcutaneous tumor model in vivo within
a time frame up to 4 h. The formed multifunctional Au DENPs synthesized
using dendrimers of low-generation may be employed as an effective
and economic nanoprobe for SPECT/CT imaging of different types of
FAR-expressing tumors
Haematoxylin and eosin staining of endometrium (original magnification, 200×).
<p>(A) eutopic endometrium. (B) ectopic endometrium. The glandular tissue (arrow) was obviously observed in eutopic endometrium (A). In ectopic endometrium(B), the neovascularization (arrow) was observed under the columnar epithelial cells (arrowhead).</p
Fe content in the surgically induced endometriotic lesions at different time points after intravenous injection of HA-Fe<sub>3</sub>O<sub>4</sub> NPs (2 mg Fe per mouse, in 1 mL PBS).
<p>Fe content in the surgically induced endometriotic lesions at different time points after intravenous injection of HA-Fe<sub>3</sub>O<sub>4</sub> NPs (2 mg Fe per mouse, in 1 mL PBS).</p
T<sub>2</sub> signal intensity value of the wall of ectopic endometriotic lesions at different time points.
<p>T<sub>2</sub> signal intensity value of the wall of ectopic endometriotic lesions at different time points.</p
The surgically induced ectopic endometriotic lesions at four weeks post operation.
<p>The tubal cystic structure with a size of 23.8×4.7×3.9 mm was noticed at the fixed site (long arrow). The ectopic lesions were full of liquids and the small dendritic vessels on the surface of the wall were also clearly observed. Note that a strip of the adhesion tissues (arrowhead) was also observed between the ectopic lesions and abdominal wall.</p
Construction of Hybrid Alginate Nanogels Loaded with Manganese Oxide Nanoparticles for Enhanced Tumor Magnetic Resonance Imaging
Development of sensitive
contrast agents for positive magnetic
resonance (MR) imaging of biosystems still remains a great challenge.
Herein, we report a facile process to construct hybrid alginate (AG)
nanogels (NGs) loaded with manganese oxide (Mn<sub>3</sub>O<sub>4</sub>) nanoparticles (NPs) for enhanced tumor MR imaging. The obtained
AG/PEI-Mn<sub>3</sub>O<sub>4</sub> NGs with a mean size of 141.6 nm
display excellent colloidal stability in aqueous solution and good
cytocompatibility in the studied concentration range. Moreover, the
hybrid NGs have a high <i>r</i><sub>1</sub> relaxivity of
26.12 mM<sup>–1</sup> s<sup>–1</sup>, which is about
19.5 times higher than that of PEI-Mn<sub>3</sub>O<sub>4</sub> NPs
with PEI surface amine acetylated (PEI.Ac–Mn<sub>3</sub>O<sub>4</sub> NPs). Furthermore, the AG/PEI-Mn<sub>3</sub>O<sub>4</sub> NGs presented longer blood circulation time and better tumor MR
imaging performances <i>in vivo</i> than PEI.Ac–Mn<sub>3</sub>O<sub>4</sub> NPs. With the good biosafety confirmed by histological
examinations, the developed AG/PEI-Mn<sub>3</sub>O<sub>4</sub> NGs
may be potentially used as an efficient contrast agent for enhanced
MR imaging of different biosystems
MR images of the ectopic endometriotic lesions at different time points.
<p>On T<sub>1</sub>WI, the EUTs (arrow) appeared as ill defined cystic mass with low signal (A). On axial FS-T<sub>2</sub>WI before injection (B), the EUTs appeared to have slightly high signal intensity surrounding with intermediate signals of fibrous walls. At 15 min (C), 30 min (D), 60 min (E), and 120 min (F) post injection, the wall of lesions were more clearly outlined and the lesion to background contrast was obviously improved compared with (A).</p