Intracellular Drug Uptake Research Articles

Enhanced Cellular Uptake and Cytotoxicity of Doxorubicin by Self-Assembled Lactobionate-Phytosterol-Alginate Nanoparticles

Amphiphilic self-assembled phytosterol-alginate nanoparticles (PA NPs) were prepared by hydrophobic modification of alginate with phytosterols. Lactobionate, a tumor-cell-specific ligand, was grafted to PA NPs for targeting the liver cancer cells (HepG2 cells) that overexpress asialoglycoprotein receptor (ASGP-R). The physicochemical properties of lactobionate-phytosterol-alginate (LPA) NPs were characterized. Doxorubicin (DOX), a broad spectrum anticancer agent, was encapsulated into prepared NPs by dialysis method. The recognition of prepared LPA NPs to HepG2 cells was ascertained by cytotoxicity and lactobionate competition assays. Because of ASGP-R-mediated endocytosis process, the DOX/LPA NPs had lower IC50 value to HepG2 cells than pure DOX and DOX/PA. The cytotoxicity of DOX/LPA NPs to HepG2 cells could be competitively inhibited by free lactobionate. The cellular uptake manner of pure DOX and DOX/LPA NPs was recognized by confocal laser scanning microscopy image and the quicker intracellular uptake of drug for DOX/LPA NPs over pure DOX was confirmed. The LPA NPs had the latent force as a promising drug carrier to target drugs to cancer cells overexpressing ASGP-R and avoid killing the cells of normal tissues.

Enhanced anticancer efficacy of folate-grafted lipid modified dual drug loaded nanoassemblies to reduce drug resistance in ovarian cancer

Non-targeted combination chemotherapy is a major clinical challenge for drug resistant ovarian cancer treatment. Lack of the specificity, adverse effect, low survival rate etc limit the chemotherapeutic treatment efficacy of drug resistance cancer. To overcome these obstacles, researchers have focused on nanotechnology based dual targeted therapies, representing a new therapeutic approach, intended to maximize intracellular drug uptake and minimize drug resistance. In this regard, folic acid (FA) conjugated lipid coated mesoporous magnetic nanoassemblies (FA-LMMNA) synthesized for targeted delivery of Doxorubicin and Paclitaxel (DOX:TXL-FA-LMMNA) has been investigated herein. This formulation provides specific targeting effect by folate conjugation, improving the anti-cancer efficacy on cisplatin sensitive and resistant ovarian cancer cells (A2780S and A2780-Cis-Res). DOX:TXL-FA-LMMNA exhibits significant enhancement in anticancer efficacy as compared to dual drug encapsulated lipid modified mesoporous magnetic nanoassemblies (DOX:TXL-LMMNA), which is a non-folate variant. We have observed a significantly higher in vitro cellular uptake and targeting efficacy of DOX:TXL-FA-LMMNA for the A2780S and A2780-Cis-Res (folate receptor positive (FR+ve)) cells due to overexpression of FR on these cell lines. In case of FR negative (FR–ve) prostate cancer (PC3) and normal fibroblast (L929) cells, no significant difference owing to FA was observed. These results suggest that DOX:TXL-FA-LMMNA has the potential activity for targeted delivery of dual drugs for treating cisplatin sensitive and resistant ovarian cancer. The present work promises to overcome the drug resistance and may open up new directions for the targeting combination chemotherapy.

Influence of serum albumin on intracellular delivery of drug-loaded hyaluronan polymeric micelles

Polymeric micelles are attractive drug delivery systems for intravenously administered nonpolar drugs. Although physical parameters like size, shape and loading capacity are considered as the most important for their efficiency, here we demonstrate that the effects of serum protein interaction and characteristics of loaded compound cannot be neglected during the micelle development and design of experimental set up. Polymeric micelles prepared from amphiphilic hyaluronic acid grafted with short (hexanoic) and long fatty acids (oleic) were tested after loading with two different hydrophobic models, Nile red and curcumin. The composition of micelles affected mainly the loading capacity. Both encapsulated compounds behaved differently in the in vitro cell uptake, which was also influenced by serum concentration, where serum albumin was found to be the primary destabilizing component. This destabilization was found to be influenced by polymeric micelle concentration. Thus, the chemical structure of micelle, the properties of non-covalently loaded substance and serum albumin/polymeric micelle ratio modulate the in vitro intracellular uptake of drugs loaded in nanocarriers.

Investigating the role of mucin in the delivery of nanoparticles to cellular models of human cancer disease: an in vitro study

Mucin, a glycosylated protein, is aberrantly overexpressed in a variety of tumor cells. The glycoprotein mesh decreases the rate of intracellular drug uptake and effectiveness. We investigated the influence of the mucin mesh on the cellular uptake of anti-MUC1 antibody and nanoparticles by fluorescence spectroscopy and microscopy. A glycosylation inhibitor (benzyl-α-GalNAc) was employed to regulate mucin glycosylation events. In our panel of pancreatic cell lines, only PANC-1 cells exhibited a significant increase in the uptake of liposomes following glycosylation inhibition, resulting in improved cytotoxicity of gemcitabine-loaded liposomes. Interestingly, areas devoid of liposome uptake were observed for pancreatic cancer cell lines PANC-1, Capan-1, and Capan-2; however, these restricted regions could be diminished for PANC1 cells only. In conclusion, investigating the reason(s) for differential cellular uptake of nanoparticles, in association with the production of mucin glycosylation mesh, should provide valuable leads to the future development of nanomedicine for cancer treatment.

Neuroprotective effect of curcumin-loaded lactoferrin nano particles against rotenone induced neurotoxicity

Curcumin is known to have neuroprotective role and possess antioxidant, anti-inflammatory activities. Rotenone, a flavonoid induced neurotoxicity in dopaminergic cells is being widely studied in Parkinson's Disease (PD) research. In the present study, curcumin loaded lactoferrin nano particles prepared by sol-oil chemistry were used to protect dopaminergic cell line SK-N-SH against rotenone induced neurotoxicity. These curcumin loaded nano particles were of 43–60 nm diameter size and around 100 nm hydrodynamic size as assessed by transmission electron microscopy, atomic force microscopy and dynamic light scattering analysis respectively. The encapsulation efficiency was 61.3% ± 2.4%. Cellular uptake of curcumin through these nano particles was confirmed by confocal imaging and spectrofluorimetric analysis. The curcumin loaded lactoferrin nanoparticles showed greater intracellular drug uptake, sustained retention and greater neuroprotection than soluble counterpart. Neuroprotective activity was characterized through viability assays and by estimating ROS levels. Furthermore rotenone induced PD like features were characterized by decrease in tyrosine hydroxylase expression and increase in α-synuclein expression. Taken together curcumin loaded lactoferrin nanoparticles could be a promising drug delivery strategy against neurotoxicity in dopaminergic neurons.

Abstract A90: Dichloroacetate can overcome drug resistance via decreased ABC drug transporter expression and PDK2 inhibition

Abstract Introduction: The primary hurdle for effective chemotherapy is the inherent or acquired drug resistance of cancer cells. The glycolytic phenotype (or Warburg effect) is a major metabolic signature of cancer cells. Dichloroacetic acid (DCA) is a non-toxic drug, which can reverse the glycolytic phenotype by inhibiting pyruvate dehydrogenase kinases (PDKs). Recent studies have linked changes in cancer cell metabolism to multi-drug resistance (MDR) phenotypes. We have examined whether reversal of the glycolytic phenotype with DCA can restore sensitivity in drug resistant cancer cells. Methodology: We examined DCA's effects in doxorubicin (DOX)-resistant MDA-MB-231 and MCF7 cells (made by continuous exposure to increasing DOX concentrations for one month) and their DOX-sensitive counterparts by neutral red cell viability assay. Intracellular drug uptake was measured by flow cytometry and expression of PDKs and drug transporters was measured by western blotting. Results: DCA treatment (1mM for 48hrs) significantly (p<0.05) enhanced DOX toxicity in DOX-resistant cells restoring sensitivity to a level similar to parental cells. This is despite DCA having no effect on DOX toxicity in parental cells. PDK2 expression was higher in the drug-selected cells compared to parental cells suggesting the sensitising effect of DCA on drug resistant cells could be an on-target effect. DCA pre-treatment increased the intracellular retention of DOX and mitoxantrone. DCA effectively reduced the expression of ATP-binding cassette (ABC) drug transporters such as P-glycoprotein and ABCG2 in DOX-resistant MDA-MB-231 and MCF7 cells and in vivo in 4T1 mouse mammary tumors. DCA pre-treatment also sensitised the MDR cell line MCF7-FLV1000 towards mitoxantrone induced apoptosis. Conclusion: DCA may be an effective chemo-sensitizing agent in a wide range of MDR cancers, acting by reducing drug transporter expression and inhibiting PDKs. Citation Format: Santhi Achuthan, Richard Callaghan, Anneke C. Blackburn. Dichloroacetate can overcome drug resistance via decreased ABC drug transporter expression and PDK2 inhibition. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr A90.

Reduction-responsive zwitterionic nanogels based on carboxymethyl chitosan for enhancing cellular uptake in drug release

Stimuli-responsive nanoparticles as drug carriers have promising applications in chemotherapy. To increase stability of nanogels in the bloodstream and to enhance intracellular drug uptake, reduction-responsive zwitterionic nanogels were prepared using carboxymethyl chitosan as a material. The preparation included modification of carboxymethyl chitosan and crosslinking by of N,N-Bis(acryloyl) cystamine. The nanogels possessed zwitterions of carboxyl and amino groups, and showed excellent non-fouling behavior against protein adsorption. In the presence of a reduction agent such as glutathione (GSH), the nanogels were dissociated due to scission of disulfide bonds in the crosslinking structure, leading to drug release in tumor cells. The nanogels were non-cytotoxic, biocompatible, biodegradable, and would be potentially used as anticancer drug delivery carriers in controlled release for enhancing cellular drug uptake.

Cytotoxicity and intracellular fate of PLGA and chitosan-coated PLGA nanoparticles in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells.

Polymeric nanoparticles (NPs) are known to facilitate intracellular uptake of drugs to improve their efficacy, with minimum bioreactivity. The goal of this study was to assess cellular uptake and trafficking of PLGA NPs and chitosan (Chi)-covered PLGA NPs in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells. Both PLGA and Chi-PLGA NPs were not cytotoxic to the studied cells at concentrations up to 2500 μg/mL. The positive charge conferred by the chitosan deposition on the PLGA NPs improved NPs uptake by MDBK cells. In this cell line, Chi-PLGA NPs colocalized partially with early endosomes compartment and showed a more consistent perinuclear localization than PLGA NPs. Kinetic uptake of PLGA NPs by Colo 205 was slower than that by MDBK cells, detected only at 24 h, exceeding that of Chi-PLGA NPs. This study offers new insights on NP interaction with target cells supporting the use of NPs as novel nutraceuticals/drug delivery systems in metabolic disorders or cancer therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3599-3611, 2015.

Plasma membrane targeting by short chain sphingolipids inserted in liposomes improves anti-tumor activity of mitoxantrone in an orthotopic breast carcinoma xenograft model

Mitoxantrone (MTO) is clinically used for treatment of various types of cancers providing an alternative for similarly active, but more toxic chemotherapeutic drugs such as anthracyclines. To further decrease its toxicity MTO was encapsulated into liposomes. Although liposomal drugs can accumulate in target tumor tissue, they still face the plasma membrane barrier for effective intracellular delivery. Aiming to improve MTO tumor cell availability, we used short chain lipids to target and modulate the tumor cell membrane, promoting MTO plasma membrane traversal. MTO was encapsulated in liposomes containing the short chain sphingolipid (SCS), C8-Glucosylceramide (C8-GluCer) or C8-Galactosylceramide (C8-GalCer) in their bilayer. These new SCS-liposomes containing MTO (SCS-MTOL) were tested in vivo for tolerability, pharmacokinetics, biodistribution, tumor drug delivery by intravital microscopy and efficacy, and compared to standard MTO liposomes (MTOL) and free MTO.Liposomal encapsulation decreased MTO toxicity and allowed administration of higher drug doses. SCS-MTOL displayed increased clearance and lower skin accumulation compared to standard MTOL. Intratumoral liposomal drug delivery was heterogeneous and rather limited in hypoxic tumor areas, yet SCS-MTOL improved intracellular drug uptake in comparison with MTOL. The increased MTO availability correlated well with the improved antitumor activity of SCS-MTOL in a MDAMB-231 breast carcinoma model. Multiple dosing of liposomal MTO strongly delayed tumor growth compared to free MTO and prolonged mouse survival, whereas among the liposomal MTO treatments, C8-GluCer-MTOL was most effective. Targeting plasma membranes with SCS improved MTO tumor availability and thereby therapeutic activity and represents a promising approach to improve MTO-based chemotherapy.

C8-glycosphingolipids preferentially insert into tumor cell membranes and promote chemotherapeutic drug uptake

Insufficient drug delivery into tumor cells limits the therapeutic efficacy of chemotherapy. Co-delivery of liposome-encapsulated drug and synthetic short-chain glycosphingolipids (SC-GSLs) significantly improved drug bioavailability by enhancing intracellular drug uptake. Investigating the mechanisms underlying this SC-GSL-mediated drug uptake enhancement is the aim of this study. Fluorescence microscopy was used to visualize the cell membrane lipid transfer intracellular fate of fluorescently labeled C6-NBD-GalCer incorporated in liposomes in tumor and non-tumor cells. Additionally click chemistry was applied to image and quantify native SC-GSLs in tumor and non-tumor cell membranes. SC-GSL-mediated flip-flop was investigated in model membranes to confirm membrane-incorporation of SC-GSL and its effect on membrane remodeling. SC-GSL enriched liposomes containing doxorubicin (Dox) were incubated at 4°C and 37°C and intracellular drug uptake was studied in comparison to standard liposomes and free Dox.SC-GSL transfer to the cell membrane was independent of liposomal uptake and the majority of the transferred lipid remained in the plasma membrane. The transfer of SC-GSL was tumor cell-specific and induced membrane rearrangement as evidenced by a transbilayer flip-flop of pyrene-SM. However, pore formation was measured, as leakage of hydrophilic fluorescent probes was not observed. Moreover, drug uptake appeared to be mediated by SC-GSLs. SC-GSLs enhanced the interaction of doxorubicin (Dox) with the outer leaflet of the plasma membrane of tumor cells at 4°C. Our results demonstrate that SC-GSLs preferentially insert into tumor cell plasma membranes enhancing cell intrinsic capacity to translocate amphiphilic drugs such as Dox across the membrane via a biophysical process.

In Vitro Investigation of the Individual Contributions of Ultrasound-Induced Stable and Inertial Cavitation in Targeted Drug Delivery

Ultrasound-mediated targeted drug delivery is a therapeutic modality under development with the potential to treat cancer. Its ability to produce local hyperthermia and cell poration through cavitation non-invasively makes it a candidate to trigger drug delivery. Hyperthermia offers greater potential for control, particularly with magnetic resonance imaging temperature measurement. However, cavitation may offer reduced treatment times, with real-time measurement of ultrasonic spectra indicating drug dose and treatment success. Here, a clinical magnetic resonance imaging-guided focused ultrasound surgery system was used to study ultrasound-mediated targeted drug delivery in vitro. Drug uptake into breast cancer cells in the vicinity of ultrasound contrast agent was correlated with occurrence and quantity of stable and inertial cavitation, classified according to subharmonic spectra. During stable cavitation, intracellular drug uptake increased by a factor up to 3.2 compared with the control. Reported here are the value of cavitation monitoring with a clinical system and its subsequent employment for dose optimization.

Evaluation of Cell Membrane-Modulating Properties of Non-Ionic Surfactants with the use of Atomic Force Spectroscopy

Analytical possibilities of atomic force spectroscopy (AFS) in liquid were studied upon interaction of membranotropic polymers with the plasma membrane of human cells. Topographical visualization of tightly adherent dermal fibroblasts, but not relatively soft prostate cancer (PC-3) cells, was achieved using a conventional triangular cantilever. A microsphere-based probe has been developed and applied for AFS analysis of micromechanical properties of PC-3 cells. Non-ionic block copolymers of ethylene oxide and propylene oxide, bi-functional Pluronic® L61, and glycerol-based tri-functional copolymer (TFC) were studied as potential modulators of cellular membranes and drug delivery systems as reported by Bondar et al. (Int. J. Pharm. 461(97), 104, 2014). As indicated by dynamic light scattering and fluorescent techniques, Pluronic® L61 and TFC were adsorbed onto the cell surface and inserted into the plasma membrane in different extent. Analysis of AFS curves for surfactant-treated PC-3 cells showed that both Pluronic® L61 and TFC decreased the Young’s modulus of cellular surface by almost 1.6 and 2 times, respectively. This is in accordance with the ability of amphiphilic polymers of decreasing the microviscosity of cellular membrane and promoting intracellular drug uptake as shown previously by Bondar et al. (Int. J. Pharm. 461(97), 104, 2014). Our results are of particular interest for the characterization of interaction of living cells with amphiphilic polymer-based nanocarriers and drug formulations using AFS and other surface-sensitive techniques.

Folate mediated self-assembled phytosterol-alginate nanoparticles for targeted intracellular anticancer drug delivery

Self-assembled core/shell nanoparticles (NPs) were synthesized from water-soluble alginate substituted by hydrophobic phytosterols. Folate, a cancer-cell-specific ligand, was conjugated to the phytosterol-alginate (PA) NPs for targeting folate-receptor-overexpressing cancer cells. The physicochemical properties of folate-phytosterol-alginate (FPA) NPs were characterized by nuclear magnetic resonance, transmission electron microscopy, dynamic light scattering, electrophoretic light scattering, and fluorescence spectroscopy. Doxorubicin (DOX), an anticancer drug, was entrapped inside prepared NPs by dialysis method. The identification of prepared FPA NPs to folate-receptor-overexpressing cancer cells (KB cells) was confirmed by cytotoxicity and folate competition assays. Compared to the pure DOX and DOX/PA NPs, the DOX/FPA NPs had lower IC50 value to KB cells because of folate-receptor-mediated endocytosis process and the cytotoxicity of DOX/FPA NPs to KB cells could be competitively inhibited by free folate. The cellular uptake and internalization of pure DOX and DOX/FPA NPs was confirmed by confocal laser scanning microscopy image and the higher intracellular uptake of drug for DOX/FPA NPs over pure DOX was observed. The FPA NPs had the potential as a promising carrier to target drugs to cancer cells overexpressing folate receptors and avoid cytotoxicity to normal tissues.

Subtype-specific binding peptides enhance the therapeutic efficacy of nanomedicine in the treatment of ovarian cancer

Currently, epithelial ovarian cancer is viewed as a heterogeneous disease with five major histological subtypes. Clear cell carcinoma represents a specific histological subtype of epithelial ovarian cancer that demonstrates more aggressive clinical behavior and drug resistance compared with other subtypes. Nevertheless, clear cell carcinoma is treated in the same manner as the other subtypes without any particular consideration to its unique clinical characteristics. To improve the therapeutic efficacy of the current liposomal doxorubicin approach for the treatment of clear cell carcinoma, we aimed to develop a novel peptide-conjugated liposomal doxorubicin to actively target this subtype. Two phage clones (OC-6 and OC-26) that specifically bound to clear cell carcinoma were isolated from a phage peptide display library after biopanning procedures. The peptide sequences were translated and aligned (OCSP-6 for OC-6, and OCSP-26 for OC-26, respectively). Peptide-conjugated nanoparticles demonstrated better tumor endocytosis and time-dependent gradual increase of intracellular drug uptake than non-targeting liposomal nanoparticles. Furthermore, peptide-conjugated liposomal doxorubicin better controlled tumors than did non-targeting liposomal doxorubicin. The current work may pave a new way for the development of drugs that target each subtype of epithelial ovarian cancer in the future.

Nanovesicular carrier-based formulation for skin cancer targeting: evaluation of cytotoxicity, intracellular uptake, and preclinical anticancer activity

Context: Skin cancer has turned into global epidemic leading to higher incidences among cancer stricken population.Objective: The aim of the present investigation is to evaluate the anticancer potential and intracellular uptake of a novel nanovesicular formulation of 5-FU.Materials and methods: Detailed intracellular uptake study in conjunction with estimation of intracellular reactive oxygen species was done using skin melanoma cell lines (A375) along with cytotoxicity studies. To further obtain the mechanistic insights into inhibition of tumor cell proliferation, cell-cycle arrest studies were conducted. The preclinical anticancer activity was carried out employing in vivo DMBA–croton oil-induced skin cancer model in mice.Results and discussion: Significant reduction in the number of papillomas was observed in skin cancer-bearing mice on treatment with nanovesicular formulation (51.4 ± 3.2%) in comparison with marketed formulation (21.3 ± 2.1%) of 5-FU. Tumor volume was found to be reduced to 46.3 ± 3.5% with prepared formulation, whereas the marketed formulation-treated group showed the reduction of 18.6 ± 1.8% in comparison with the control (untreated) group.Conclusion: The results of present study demonstrated that nanovesicular formulation of 5-FU possessed the enhanced anticancer activity which could be attributed to better intracellular uptake, cellular retention, and sustained release of drug.

Carboxymethyl-β-cyclodextrin conjugated nanoparticles facilitate therapy for folate receptor-positive tumor with the mediation of folic acid

Currently, clinical operation treatments, chemotherapy and radiotherapy just could eliminate local tumor cells. However, chemotherapy and radiotherapy also injury normal cells and lead to serious side effects and toxicities. So, it is necessary to find an effective target cancer carrier that delivers the anticancer agents into tumor cells and reduces normal cells’ injury. Folic acid (FA) is a classical targeting agent mediates internalization of chemical drugs into tumor cells which over-express folate receptor (FR) on their surface. We herein report that based on host–guest interaction, NPs decorated by novel folate enhance antitumor drug delivery. BSA-NPs were prepared by desolvation method and carboxymethyl-β-cyclodextrin (CM-β-CD) was conjugated to the surface of NPs by carbodiimide coupling to hold FA. From in vitro cytotoxicity assay, cell apoptosis study, intracellular ATP level assay and western blot, we can see that FA-CM-β-CD-BSA NPs as good monodispersity, negative charge, and homogenous particle size have a high encapsulation efficiency. The results showed that MTT and cell apoptosis demonstrated that FA-decorated NPs exhibit stronger inhibition rate and induce obvious apoptosis in FR positive Hela cells as compared to free drug and FA undecorated NPs. Moreover, 5-fluorouracil (5-Fu) loaded FA-CM-β-CD-BSA NPs down-regulate ATP levels and increase the expression of caspase-3. Taken together, FA-CM-β-CD-BSA NPs enhance FR receptor-mediated endocytosis and lead to more intracellular uptake of drug, inducing the higher apoptosis ratio of cells than free 5-Fu.

Enhanced localization of anticancer drug in tumor tissue using polyethylenimine-conjugated cationic liposomes.

Liposome-based drug delivery systems hold great potential for cancer therapy. However, to enhance the localization of payloads, an efficient method of systemic delivery of liposomes to tumor tissues is required. In this study, we developed cationic liposomes composed of polyethylenimine (PEI)-conjugated distearoylglycerophosphoethanolamine (DSPE) as an enhanced local drug delivery system. The particle size of DSPE-PEI liposomes was 130 ± 10 nm and the zeta potential of liposomes was increased from -25 to 30 mV by the incorporation of cationic PEI onto the liposomal membrane. Intracellular uptake of DSPE-PEI liposomes by tumor cells was 14-fold higher than that of DSPE liposomes. After intratumoral injection of liposomes into tumor-bearing mice, DSPE-PEI liposomes showed higher and sustained localization in tumor tissue compared to DSPE liposomes. Taken together, our findings suggest that DSPE-PEI liposomes have the potential to be used as effective drug carriers for enhanced intracellular uptake and localization of anticancer drugs in tumor tissue through intratumoral injection.

Erratum to: Folate-conjugated chitosan–polylactide nanoparticles for enhanced intracellular uptake of anticancer drug

Erratum to: Folate-conjugated chitosan–polylactide nanoparticles for enhanced intracellular uptake of anticancer drug

Rational design for multifunctional non-liposomal lipid-based nanocarriers for cancer management: theory to practice

Nanomedicines have gained more and more attention in cancer therapy thanks to their ability to enhance the tumour accumulation and the intracellular uptake of drugs while reducing their inactivation and toxicity. In parallel, nanocarriers have been successfully employed as diagnostic tools increasing imaging resolution holding great promises both in preclinical research and in clinical settings. Lipid-based nanocarriers are a class of biocompatible and biodegradable vehicles that provide advanced delivery of therapeutic and imaging agents, improving pharmacokinetic profile and safety. One of most promising engineering challenges is the design of innovative and versatile multifunctional targeted nanotechnologies for cancer treatment and diagnosis. This review aims to highlight rational approaches to design multifunctional non liposomal lipid-based nanocarriers providing an update of literature in this field.

Copper-free azide–alkyne cycloaddition of targeting peptides to porous silicon nanoparticles for intracellular drug uptake

Porous silicon (PSi) has been demonstrated as a promising drug delivery vector for poorly water-soluble drugs. Here, a simple and efficient method based on copper-free click chemistry was used to introduce targeting moieties to PSi nanoparticles in order to enhance the intracellular uptake and tumor specific targeting hydrophobic drug delivery. Two RGD derivatives (RGDS and iRGD) with azide-terminated groups were conjugated to bicyclononyne-functionalized PSi nanoparticles via copper-free azide–alkyne cycloaddition. The surface functionalization was performed in aqueous solution at 37 °C for 30 min resulting in conjugation efficiencies of 15.2 and 3.4% (molar ratios) and the nanoparticle size increased from 165.6 nm to 179.6 and 188.8 nm for RGDS and iRGD, respectively. The peptides modification enhanced the cell uptake efficiency of PSi nanoparticles in EA.hy926 cells. PSi-RGDS and PSi-iRGD nanoparticles loaded with sorafenib showed a similar trend for the in vitro antiproliferation activity compared to sorafenib dissolved in dimethyl sulfoxide. Furthermore, sorafenib-loaded PSi-RGDS deliver the drug intracellulary efficiently due to the higher surface conjugation ratio, resulting in enhanced in vitro antiproliferation effect. Our results highlight the surface functionalization methodology for PSi nanoparticles applied here as a universal method to introduce functional moieties onto the surface of PSi nanoparticles and demonstrate their potential active targeting properties for anticancer drug delivery.