11 research outputs found
Molecular weight-dependent activity of aminated poly(α)glutamates as siRNA nanocarriers
RNA interference (RNAi) can contribute immensely to the area of personalized medicine by its ability to target any gene of interest. Nevertheless, its clinical use is limited by lack of efficient delivery systems. Polymer therapeutics can address many of the challenges encountered by the systemic delivery of RNAi, but suffer from inherent drawbacks such as polydispersity and batch to batch heterogeneity. These characteristics may have far-reaching consequences when dealing with therapeutic applications, as both the activity and the toxicity may be dependent on the length of the polymer chain. To investigate the consequences of polymers’ heterogeneity, we have synthesized two batches of aminated poly(α)glutamate polymers (PGAamine), differing in their degree of polymerization, but not in the monomer units or their conjugation. Isothermal titration calorimetry study was conducted to define the binding affinity of these polymers with siRNA. Molecular dynamics simulation revealed that Short PGAamine:siRNA polyplexes exposed a higher amount of amine moieties to the surroundings compared to Long PGAamine. This resulted in a higher zeta potential, leading to faster degradation and diminished gene silencing. Altogether, our study highlights the importance of an adequate physico-chemical characterization to elucidate the structure–function-activity relationship, for further development of tailor-designed RNAi delivery vehicles
Image-guided surgery using near-infrared Turn-ON fluorescent nanoprobes for precise detection of tumor margins
4D printing of biodegradable elastomers with tailorable thermal response at physiological temperature
4D printing has a great potential for the manufacturing of soft robotics and medical devices. The alliance of digital light processing (DLP) 3D printing and novel shape-memory photopolymers allows for the fabrication of smart 4D-printed medical devices in high resolution and with tailorable functionalities. However, most of the reported 4D-printed materials are nondegradable, which limits their clinical applications. On the other hand, 4D printing of biodegradable shape-memory elastomers is highly challenging, especially when transition points close to physiological temperature and shape fixation under ambient conditions are required. Here, we report the 4D printing of biodegradable shape-memory elastomers with tailorable transition points covering physiological temperature, by using poly(D,L-lactide-co-trimethylene carbonate) methacrylates at various monomer feed ratios. After the programming step, the high-resolution DLP printed stents preserved their folded shape at room temperature, and showed efficient shape recovery at 37 °C. The materials were cytocompatible and readily degradable under physiological conditions. Furthermore, drug-loaded devices with tuneable release kinetics were realized by DLP-printing with resins containing polymers and levofloxacin or nintedanib. This study offers a new perspective for the development of next-generation 4D-printed medical devices.ISSN:0168-3659ISSN:1873-499
Sulfonated Amphiphilic Poly(α)glutamate Amine—A Potential siRNA Nanocarrier for the Treatment of Both Chemo-Sensitive and Chemo-Resistant Glioblastoma Tumors
Development of chemo-resistance is a major challenge in glioblastoma (GB) treatment. This phenomenon is often driven by increased activation of genes associated with DNA repair, such as the alkyl-removing enzyme O6-methylguanine-DNA methyltransferase (MGMT) in combination with overexpression of canonical genes related to cell proliferation and tumor progression, such as Polo-like kinase 1 (Plk1). Hereby, we attempt to sensitize resistant GB cells using our established amphiphilic poly(α)glutamate (APA): small interfering RNA (siRNA) polyplexes, targeting Plk1. Furthermore, we improved brain-targeting by decorating our nanocarrier with sulfonate groups. Our sulfonated nanocarrier showed superior selectivity towards P-selectin (SELP), a transmembrane glycoprotein overexpressed in GB and angiogenic brain endothelial cells. Self-assembled polyplexes of sulfonated APA and siPlk1 internalized into GB cells and into our unique 3-dimensional (3D) GB spheroids inducing specific gene silencing. Moreover, our RNAi nanotherapy efficiently reduced the cell viability of both chemo-sensitive and chemo-resistant GB cells. Our developed sulfonated amphiphilic poly(α)glutamate nanocarrier has the potential to target siRNA to GB brain tumors. Our findings may strengthen the therapeutic applications of siRNA for chemo-resistant GB tumors, or as a combination therapy for chemo-sensitive GB tumors
StructureâFunction Correlation of Aminated Poly(α)glutamate as siRNA Nanocarriers
It
has been two decades since cationic polymers were introduced
to the world of oligonucleotides delivery. However, the optimal physicochemical
properties to make them a successful delivery vehicle are yet unknown.
An ideal system became particularly interesting and necessary with
the introduction of RNA interference as a promising therapeutic approach.
Such nanocarrier should overcome challenges such as low plasma stability,
poor cellular internalization and endosomal escape to induce gene
silencing. To that end, we synthesized a library of biodegradable
aminated polyÂ(α)Âglutamate varied by amine moieties. In an attempt
to elucidate the structureâfunction relationship, our polyplexes
were physicochemically characterized and their silencing activity
and cytotoxicity were evaluated. We found several structures that
demonstrated improved cellular internalization. These candidates silenced
gene expression to less than 50% of their initial levels, while being
safe to cells and mice. Based on our research, an improved and promising
tailor-designed siRNA delivery platform can be developed
Amphiphilic poly(α)glutamate polymeric micelles for systemic administration of siRNA to tumors
\u3cp\u3eRNAi therapeutics carried a great promise to the area of personalized medicine: the ability to target âundruggableâ oncogenic pathways. Nevertheless, their efficient tumor targeting via systemic administration had not been resolved yet. Amphiphilic alkylated poly(α)glutamate amine (APA) can serve as a cationic carrier to the negatively-charged oligonucleotides. APA polymers complexed with siRNA to form round-shaped, homogenous and reproducible nano-sized polyplexes bearing ~50 nm size and slightly negative charge. In addition, APA:siRNA polyplexes were shown to be potent gene regulators in vitro. In light of these preferred physico-chemical characteristics, their performance as systemically-administered siRNA nanocarriers was investigated. Intravenously-injected APA:siRNA polyplexes accumulated selectively in tumors and did not accumulate in the lungs, heart, liver or spleen. Nevertheless, the polyplexes failed to induce specific mRNA degradation, hence neither reduction in tumor volume nor prolonged mice survival was seen.\u3c/p\u3
Tough PEGâonly hydrogels with complex 3D structure enabled by digital light processing of âallâPEGâ resins
Abstract Digital light processing (DLP) of structurally complex poly(ethylene glycol) (PEG) hydrogels with high mechanical toughness represents a longâstanding challenge in the field of 3D printing. Here, we report a 3D printing approach for the highâresolution manufacturing of structurally complex and mechanically strong PEG hydrogels via heatâassisted DLP. Instead of using aqueous solutions of photoâcrosslinkable monomers, PEG macromonomer melts were first printed in the absence of water, resulting in bulk PEG networks. Then, postâprinting swelling of the printed networks was achieved in water, producing highâfidelity 3D hydrogels with complex structures. By employing a dualâmacromonomer resin containing a PEGâbased fourâarm macrophotoinitiator, âallâPEGâ hydrogel constructs were produced with compressive toughness up to 1.3Â MJÂ mâ3. By this approach, porous 3D hydrogel scaffolds with trabecularâlike architecture were fabricated, and the scaffold surface supported cell attachment and the formation of a monolayer mimicking boneâlining cells. This study highlights the promises of heatâassisted DLP of PEG photopolymers for hydrogel fabrication, which may accelerate the development of 3D tissueâlike constructs for regenerative medicine
Tough PEG-only hydrogels with complex 3D structure enabled by digital light processing of "all-PEG" resins
Digital light processing (DLP) of structurally complex poly(ethylene glycol) (PEG) hydrogels with high mechanical toughness represents a long-standing challenge in the field of 3D printing. Here, we report a 3D printing approach for the high-resolution manufacturing of structurally complex and mechanically strong PEG hydrogels via heat-assisted DLP. Instead of using aqueous solutions of photo-crosslinkable monomers, PEG macromonomer melts were first printed in the absence of water, resulting in bulk PEG networks. Then, post-printing swelling of the printed networks was achieved in water, producing high-fidelity 3D hydrogels with complex structures. By employing a dual-macromonomer resin containing a PEG-based four-arm macrophotoinitiator, "all-PEG" hydrogel constructs were produced with compressive toughness up to 1.3 MJ m(-3). By this approach, porous 3D hydrogel scaffolds with trabecular-like architecture were fabricated, and the scaffold surface supported cell attachment and the formation of a monolayer mimicking bone-lining cells. This study highlights the promises of heat-assisted DLP of PEG photopolymers for hydrogel fabrication, which may accelerate the development of 3D tissue-like constructs for regenerative medicine.ISSN:2692-456
Identification of Dormancy-Associated MicroRNAs for the Design of Osteosarcoma-Targeted Dendritic Polyglycerol Nanopolyplexes
The
presence of dormant, microscopic cancerous lesions poses a
major obstacle for the treatment of metastatic and recurrent cancers.
While it is well-established that microRNAs play a major role in tumorigenesis,
their involvement in tumor dormancy has yet to be fully elucidated.
We established and comprehensively characterized pairs of dormant
and fast-growing human osteosarcoma models. Using these pairs of mouse
tumor models, we identified three novel regulators of osteosarcoma
dormancy: miR-34a, miR-93, and miR-200c. This report shows that loss
of these microRNAs occurs during the switch from dormant avascular
into fast-growing angiogenic phenotype. We validated their downregulation
in patientsâ tumor samples compared to normal bone, making
them attractive candidates for osteosarcoma therapy. Successful delivery
of miRNAs is a challenge; hence, we synthesized an aminated polyglycerol
dendritic nanocarrier, dPG-NH<sub>2</sub>, and designed dPG-NH<sub>2</sub>-microRNA polyplexes to target cancer. Reconstitution of these
microRNAs using dPG-NH<sub>2</sub> polyplexes into Saos-2 and MG-63
cells, which generate fast-growing osteosarcomas, reduced the levels
of their target genes, MET proto-oncogene, hypoxia-inducible factor
1α, and moesin, critical to cancer angiogenesis and cancer cellsâ
migration. We further demonstrate that these microRNAs attenuate the
angiogenic capabilities of fast-growing osteosarcomas <i>in vitro</i> and <i>in vivo</i>. Treatment with each of these microRNAs
using dPG-NH<sub>2</sub> significantly prolonged the dormancy period
of fast-growing osteosarcomas <i>in vivo</i>. Taken together,
these findings suggest that nanocarrier-mediated delivery of microRNAs
involved in osteosarcoma tumorâhost interactions can induce
a dormant-like state