Fabrication and evaluation of aptamer-conjugated paclitaxel-loaded magnetic nanoparticles for targeted therapy on breast cancer cells

Targeted drug delivery vehicles make it possible to deliver anti-cancer drugs to the cells or tissues of interest. Aptamers are peptide or oligonucleotide molecules that can serve as targeting elements of drug carriers. In the current study, we evaluated the capacity of an aptamer-based drug carrier to deliver Paclitaxel (PTX) to cancer cells. After being synthesized, SPIONs@PTX-SYL3C aptamer was characterized using different methods, including differential light scattering (DLS), infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Encapsulation efficiency (EE) and loading efficiency (LE) were also evaluated. The carrier was applied on 4T1, MCF 7, and MCF-10A breast cell lines to evaluate its drug delivery potency and specificity. EE and LE were calculated to be 77.6% and 7.76%, respectively. MTT results revealed that aptameric SPIONs@PTX was more toxic than non-aptameric SPIONs@PTX. Flowcytometry analysis and DAPI staining confirmed that SPIONs@PTX-Aptamer had higher cell internalization rate when compared to non-targeted SPIONs@PTX. Our results indicate that aptamer-conjugated SPIONs@PTX has a good capacity in recognizing its target cells and inhibiting their growth and division.

TME-Responsive Polyprodrug Micelles for Multistage Delivery of Doxorubicin with Improved Cancer Therapeutic Efficacy in Rodents

It is of great significance to develop multifunctional biomaterials to effectively deliver anticancer drug to tumor cells for cancer therapy. Here, inspired by the specific tumor microenvironment (TME) cues, a unique multistage pH/redox-responsive polyprodrug composed of amphiphilic pH-sensitive diblock copolymer poly(ethylene glycol) methyl ether-b-poly(β-amino esters) conjugated with doxorubicin (DOX) via redox-sensitive disulfide bonds (mPEG-b-PAE-ss-DOX) is designed and developed. This polyprodrug can self-assemble into micelles (DOX-ss@PMs) at low concentration with high serum stability, indicating that DOX-ss@PMs have prolonged circulation time. The dual pH/redox-responsiveness of the multistage platform is thoroughly evaluated. In vitro results demonstrate that DOX-ss@PMs can highly accumulate at tumor site, followed by responding to the acidity for disassembly and effectively penetrating into the tumor cells. DOX is released from the platform due to the cleavage of disulfide bonds induced by high glutathione (GSH) concentration, thereby inducing the apoptosis of tumor cells. In vivo studies further reveal that multistage DOX-ss@PMs can more efficiently inhibit the growth of tumors and improve the survival of tumor-bearing mice in comparison to the free drug and control. These results imply that multistage delivery system might be a potential and effective strategy for drug delivery and DOX-ss@PMs could be a promising nanomedicine for cancer chemotherapy.

Design and fabrication of dual-targeted delivery system based on gemcitabine-conjugated human serum albumin nanoparticles

Dual-targeted drug delivery system has established their reputation as potent vehicles for cancer chemotherapies. Herein, gemcitabine (Gem) was conjugated to human serum albumin (HSA) via dithiodipropionic anhydride to fabricate Gem-HSA nanoparticles. It was hypothesized that this system can enhance the low stability of Gem and can improve its intracellular delivery. Furthermore, folate was applied as targeting agent on HSA nanoparticles for increasing the tumor selectivity of Gem. To evaluate the structural properties of synthesized products, ¹ H NMR and FT-IR were performed. Moreover, HPLC was implemented for confirming the conjugation between HSA and Gem. Nanoparticles have shown spherical shape with negative charge. The release rate of Gem was dependent to the concentration of glutathione and pH. Folate-targeted HSA nanoparticles have shown higher cytotoxicity, cellular uptake, and apoptosis induction on folate receptor overexpressing MDA-MB-231 cells in comparison to non-targeted nanoparticles. Finally, it is considered that the developed dual-targeted nanoparticles would be potent in improving the stability and efficacy of intracellular delivery of Gem and its selective delivery to cancer cells.

Functionalized Multiarmed Polycaprolactones as Biocompatible Tissue Adhesives

Existing tissue adhesives have a trade-off between adhesive strength and biocompatibility. Here, we report a series of biocompatible multiarmed polycaprolactones (PCL) as tissue adhesives that can be released from a hot glue gun and the length of each arm was kept at ∼2-3 kg mol^-1 in all the polymers. The adhesion properties were dependent on the number of functionalized (N-hydroxysuccinimide ester (NHS), aldehyde (CHO), and isocyanate (NCO)) arms of the multiarmed polymers. The more arms, the higher the adhesion strength. For example, the adhesion strength in binding cut rat skin increased from 2.3 N cm^-2 for 2PCL-NHS to 11.2 N cm^-2 for 8-PCL-NHS. CHO- and NCO-modified 8PCL also had suitable adhesive properties. All the multiarmed polymers had minimal cytotoxicity in vitro and good biocompatibility in vivo, suggesting their potential as promising alternative surgical adhesives.

Polydopamine-Derivated Hierarchical Nanoplatforms for Efficient Dual-Modal Imaging-Guided Combination in Vivo Cancer Therapy

Exploring multifunctional nanomaterials from biocompatible constituents, with integrated imaging and targeted combination therapeutic modalities of tumors in vivo, provides great prospects for clinical cancer theranostic applications. Here, we report a combination strategy for functionalization of polydopamine (PDA) nanohosts with magnetic response and stimuli-controlled drug release capabilities for in vivo cancer theranostic. The high processability of PDA as nanotemplates and surface coating layers as well as its natural affinity to metals facilitated the sandwich of a compact iron oxide nanoparticle layer into the PDA matrix, realizing enhanced near-infrared (NIR) photothermal conversion and strong superparamagnetic responsiveness. Additionally, the high reactivity of the PDA surface allowed facile linkage with reduction-responsive prodrugs and polyethylene glycol chains for in vivo chemotherapy of cancer. Under the magnetic resonance imaging/photoacoustic imaging dual-modal tumor imaging and active magnetic tumor targeting of the nanoagents in vivo, the effective tumor eradication was achieved via synergetic NIR photothermal ablation and anticancer drug delivery.

Redox-Sensitive Micelles Based on O,N-Hydroxyethyl Chitosan-Octylamine Conjugates for Triggered Intracellular Delivery of Paclitaxel

A redox-sensitive micellar system constructed from an O,N-hydroxyethyl chitosan-octylamine (HECS-ss-OA) conjugate with disulfide linkages between the hydrophobic alkyl chains and hydrophilic chitosan backbone was synthesized for triggered intracellular delivery of hydrophobic paclitaxel (PTX). In aqueous environments, conjugates formed micelles with high PTX loading (>30%). Mechanistically, the sensitivity of HECS-ss-OA micelles to reducing environments was investigated using the parameters of in vitro release and particle size. Intracellular release of nile red fluorescence alongside cytotoxicity studies further confirmed the potency of redox-sensitive micelles for intracellular drug delivery compared with redox-insensitive micelles. Additionally, an in vivo study confirmed the efficacy of PTX-loaded micelles in tumor-bearing mice with superior antitumor efficacy and diminished systemic toxicity when compared with the redox-insensitive micelles and a PTX solution. These results demonstrate the potential of redox-sensitive HECS-ss-OA micelles for intracellular trafficking of lipophilic anticancer drugs.

Reduction-sensitive polymeric nanocarriers in cancer therapy: a comprehensive review

Redox potential is regarded as a significant signal to distinguish between the extra-cellular and intra-cellular environments, as well as between tumor and normal tissues. Taking advantage of this physiological differentiation, various reduction-sensitive polymeric nanocarriers (RSPNs) have been designed and explored to demonstrate excellent stability during blood circulation but rapidly degrade and effectively trigger drug release in tumor cells. Therefore, this smart RSPN delivery system has attracted much attention in recent years, as it represents one of the most promising drug delivery strategies in cancer therapy. In this review, we will provide a comprehensive overview of RSPNs with various reducible linkages and functional groups up to date, including their design and synthetic strategies, preparation methods, drug release behavior, and their in vitro and in vivo efficacy in cancer therapy. In addition, dual- and triple-sensitive nanocarriers based on reducible disulfide bond-containing linkages will also be discussed.

Nanoparticles of deoxycholic acid, polyethylene glycol and folic acid-modified chitosan for targeted delivery of doxorubicin

Chitosan (CS) was first modified hydrophobically with deoxycholic acid (DCA) and then with polyethylene glycol (PEG) to obtain a novel amphiphilic polymer (CS-DCA-PEG). This was covalently bound to folic acid (FA) to develop nanoparticles (CS-DCA-PEG-FA) with tumor cell targeting property. The structure of the conjugates was characterised using Fourier transform infrared and (1)H nuclear magnetic resonance spectroscopy and X-ray diffraction. Based on self-aggregation, the conjugates formed nanoparticles with a low critical aggregation concentration of 0.035 mg/ml. The anti-cancer drug doxorubicin (DOX) was encapsulated into the nanoparticles with a drug-loading capacity of 30.2 wt%. The mean diameter of the DOX-loaded nanoparticles was about 200 nm, with a narrow size distribution. Transmission electron microscopy images showed that the DOX-loaded nanoparticles were spherical. The drug release was studied under different conditions. Furthermore, the cytotoxic activities of DOX in CS-DCA-PEG-FA nanoparticles against folate receptor (FR)-positive HeLa cells and FR-negative fibroblast 3T3 cells were evaluated. These results suggested that the CS-DCA-PEG-FA nanoparticles may be a promising vehicle for the targeting anticancer drug to tumor cells.