Controlled release of a sparingly water-soluble anticancer drug through pH-responsive functionalized gold-nanoparticle-decorated liposomes

Effects of Fluorinated Functionalization of Linker on Quercetin Encapsulation, Release and Hela Cell Cytotoxicity of Cu-Based MOFs as Smart pH-Stimuli Nanocarriers

Controlled delivery of target molecules is required in many medical and chemical applications. For such purposes, metal-organic frameworks (MOFs), which possess desirable features such as high porosity, large surface area, and adjustable functionalities, hold great potential as drug carriers. Herein, Quercetin (QU), as an anticancer drug, was loaded on Cu2 (BDC)2 (DABCO) and Cu2 (F4 BDC)2 )DABCO) MOFs (BDC=1,4-benzenedicarboxylate and DABCO=1,4-diazabicyclo[2.2.2]octane). As these Cu-MOFs have a high surface area, an appropriate pore size, and biocompatible ingredients, they can be utilized to deliver QU. The loading efficiency of QU in these MOFs was 49.5 % and 41.3 %, respectively. The drug-loaded compounds displayed sustained drug release over 15 days, remarkably high drug loading capacities and pH-controlled release behavior. The prepared nanostructures were characterized by different characterization technics including FT-IR, PXRD, ZP, TEM, FE-SEM, UV-vis, and BET. In addition, MTT assays were carried out on the HEK-293 and HeLa cell lines to investigate cytotoxicity. Cellular apoptosis analysis was performed to investigate the cell death mechanisms. Grand Canonical Monte Carlo simulations were conducted to analyze the interactions between MOFs and QU. Moreover, the stability of MOFs was also investigated during and after the drug release process. Ultimately, kinetic models of drug release were evaluated.

"On-Off" Switching of Functional Guest Molecules via Exchange of Natural Product Solubilizing Agents

For the development of delivery systems, the solubilization of hydrophobic guest molecules in water is an important yet challenging task. This can be achieved by preparing stable aqueous solutions with a high concentration of guest molecules using a natural product as a solubilizing agent and a mechanochemical high-speed vibration milling apparatus as a solubilizing method. Various solubilizing agent-guest molecule complexes can be obtained via the exchange between solubilizing agents, which enables the "on-off" switching of the properties of functional guest molecules, such as fluorescence intensity, and photodynamic activity. In the exchange method, guest molecules can transfer into cell membranes such as lysosomes and exosomes. Therefore, the exchange method of the solubilizing agents not only creates novel solubilizing agent-guest molecule complexes but also is applied to drug delivery systems.

Selective Photodynamic Activity of Tetrakis(4-aminophenyl)porphyrins with and without Acetyl Protecting Groups on Cancer and Normal Cells

Tetrakis(4-aminophenyl)porphyrin (1) and tetrakis(4-acetamidophenyl)porphyrin (2) were dissolved in water with the incorporation of a polysaccharide (λ-carrageenan (CGN)) as a water-solubilizing agent. Although the photodynamic activity of the CGN-2 complex was considerably lower than that of the CGN-1 complex, the selectivity index (SI; IC50 in a normal cell/IC50 in a cancer cell) of the CGN-2 complex was considerably higher than that of the CGN-1 complex. This is because the photodynamic activity of the CGN-2 complex was significantly affected by the intracellular uptakes by the normal and cancer cells. During in vivo experiments, the CGN-2 complex inhibited tumor growth under light irradiation with high blood retention compared with the CGN-1 complex and Photofrin, which exhibited lower blood retention. This study showed that the photodynamic activity and SI are influenced by substituent groups of arene in the meso-positions of porphyrin analogs.

Remodeling Collagen Microenvironment in Liver Using a Biomimetic Nano-Regulator for Reversal of Liver Fibrosis

Liver fibrosis is a progressive histological manifestation that happens in almost all chronic liver diseases. An unabated liver fibrosis may eventually develop into liver cirrhosis or hepatocellular carcinoma. Yet, the strategy for reversal of liver fibrosis is still limited. Herein, a biomimetic nano-regulator (P-ZIF8-cirDNAzyme) is developed to affect both collagen synthesis and degradation in liver to remodel collagen microenvironment. It is found that Zn (II) interference can efficiently inhibit collagen synthesis in activated hepatic stellate cells (aHSC) by inactivating proline 4 hydroxylase and affecting many fibrosis-related signaling pathways. Meanwhile, Zn (II)-dependent circular DNAzymes (cirDNAzymes) are used to efficiently silence tissue inhibitors of metalloproteinase-1, accelerating the degradation of collagen. They act in concert to recover the balance between collagen deposition and degradation. Additionally, ZIF-8-cirDNAzyme is coated by platelet membrane (PM) for precisely targeting aHSC via PM's inflammatory tropism and CD62p-CD44 interaction. In carbon tetrachloride-induced fibrotic mice, P-ZIF-8-cirDNAzyme shows a potent anti-fibrotic effect, greatly reducing the expression of collagen by 73.12% and restoring liver function nearly to normal. This work proposes a prospective platform enabling ion interference and gene silencing, collectively acting in aHSC for reversal of liver fibrosis.

Development and characterization of chitosan nanoparticles containing an indanonic tricyclic spiroisoxazoline derivative using ion-gelation method: an in vitro study

Biodegradable nanoparticulate carriers are potentially applicable compounds in the administration of therapeutic agents and drug delivery. They have received much attention due to their biological characteristics such as biodegradability, biocompatibility, and bioadhesive. The objectives of this work are first, investigating the impact of two important parameters (i.e. chitosan or sodium tripolyphosphate (TPP) solution concentration and chitosan to TPP mass ratio) on the chitosan nanoparticles (CNPs) formation by ionic-gelation method and then, the synthesis and characterization of chitosan-based, biodegradable drug-loaded nanoparticles in the encapsulation of novel 4'-(4-(methylsulfonyl)phenyl)-3'-(3,4,5-trimethoxyphenyl)-4'H-spiro[indene-2,5'-isoxazol]-1(3H)-one (MTS) indanonic tricyclic spiroisoxazoline, which is a potent anticancer drug. The particle size, shape, zeta potential, drug loading capacity, in vitro release characteristics, and stability of the formulated drug-loaded nanoparticles of the different drug:carrier ratio has been studied. The results indicated that the particle size increased at the higher chitosan or TPP concentration while the mass ratio did not appear to be a significant parameter during the cross-linking process. The particle diameter and zeta potential of CNPs including MTS were approximately in the range of 256-350 nm and 24.08-38.70 mV, respectively. The entrapment efficiency steadily increased with increasing the concentration of the polymer in formulizations. Throughout 24 h, the in vitro release behavior was provided a sustained release from all the drug-loaded formulizations. The optimal formulization of CNPs based on drug content with a drug:carrier ratio of 1:2 did not change appreciably during 60-day storage at either 4 °C or the ambient temperature.

Effect of Surface Ligand and Temperature on Lipid Vesicle-Gold Nanoparticle Interaction: A Spectroscopic Investigation

We herein investigate the interactions of differently functionalized anionic and cationic gold nanoparticles (AuNPs) with zwitterionic phosphocholine (PC) as well as inverse phosphocholine (iPC) lipid bilayers via spectroscopic measures. In this study, we used PC lipids with varying phase-transition temperatures, i.e., DMPC ( T_m = 24 °C), DOPC ( T_m = -20 °C), and iPC lipid DOCP ( T_m = -20 °C) to study their interactions with AuNPs functionalized with anionic ligands citrate, 3-mercaptopropionic acid, glutathione, and cationic ligand cysteamine. We studied the interactions by steady-state and time-resolved spectroscopic studies using membrane-sensitive probes 6-propionyl-2-dimethylaminonaphthalene (PRODAN) and 8-anilino-1 naphthalenesulfonate (ANS), as well as by confocal laser scanning microscopy (CLSM) imaging and dynamic light scattering (DLS) measurements. We observe that AuNPs bring in stability to the lipid vesicle, and the extent of interaction differs with the different surface ligands on the AuNPs. We observe that AuNPs functionalized with citrate effectively increase the phase-transition temperature of the vesicles by interacting with them. Our study reveals that the extent of interaction depends on the bulkiness of the ligands attached to the AuNPs. The bulkier ligands exert less van der Waals force, resulting in a weaker interaction. Moreover, we find that the interactions are more strongly pronounced when the vesicles are near the phase-transition temperature of the lipid.  The CLSM imaging and DLS measurements demonstrate the surface modifications in the vesicles as a result of these interactions.

Adsorption of tetrakis(4-sulfophenyl)porphyrin onto liposomal surfaces composed of neutral diacylphosphatidylcholine and release by cyclodextrin

Anionic tetrakis(4-sulfophenyl)porphyrin (TPPS) interacts with liposomal surfaces composed of neutral diacylphosphatidylcholine at high lipid concentrations. TPPS interacted with liposomal surfaces through four contact points. The association constant was obtained to be 9.0 × 10⁵ M⁻⁴. TPPS was peeled off the liposomal surfaces by the addition of cyclodextrin.

Interactions between tetrakis(4-sulfophenyl)porphyrin and liposomal surfaces with neutral diacylphosphatidylcholine occurred and can be controlled by the addition of cyclodextrin.

Preparation of liposomes containing small gold nanoparticles using electrostatic interactions

The development of liposome-nanoparticle colloid systems offers a versatile approach towards the manufacture of multifunctional therapeutic platforms. A strategy to encapsulate small metallic nanoparticles (<4nm) within multilamellar vesicles, effected by exploiting electrostatic interactions was investigated. Two liposome-gold nanoparticle (lipo-GNP) systems were prepared by the reverse-phase evaporation method employing cationic or anionic surface functionalised particles in combination with oppositely charged lipid compositions with subsequent post-formulation PEGylation. Structural characterisation using electron microscopy and elemental analysis revealed a regular distribution of GNPs between adjacent lipid bilayers of intact liposomes. Nanoparticle encapsulation efficacy of the two lipo-GNP systems was revealed to be significantly different (p=0.03), evaluated by comparing the ratio of measured lipid to gold concentration (loading content) determined by a colorimetric assay and atomic emission spectroscopy, respectively. It was concluded that the developed synthetic strategy is an effective approach for the preparation of liposome-nanoparticle colloids with potential to control the relative concentration of encapsulated particles to lipids by providing favourable electrostatic interactions.

Surface Modified Multifunctional and Stimuli Responsive Nanoparticles for Drug Targeting: Current Status and Uses

Nanocarriers, due to their unique features, are of increased interest among researchers working with pharmaceutical formulations. Polymeric nanoparticles and nanocapsules, involving non-toxic biodegradable polymers, liposomes, solid lipid nanoparticles, and inorganic-organic nanomaterials, are among the most used carriers for drugs for a broad spectrum of targeted diseases. In fact, oral, injectable, transdermal-dermal and ocular formulations mainly consist of the aforementioned nanomaterials demonstrating promising characteristics such as long circulation, specific targeting, high drug loading capacity, enhanced intracellular penetration, and so on. Over the last decade, huge advances in the development of novel, safer and less toxic nanocarriers with amended properties have been made. In addition, multifunctional nanocarriers combining chemical substances, vitamins and peptides via coupling chemistry, inorganic particles coated by biocompatible materials seem to play a key role considering that functionalization can enhance characteristics such as biocompatibility, targetability, environmental friendliness, and intracellular penetration while also have limited side effects. This review aims to summarize the "state of the art" of drug delivery carriers in nanosize, paying attention to their surface functionalization with ligands and other small or polymeric compounds so as to upgrade active and passive targeting, different release patterns as well as cell targeting and stimuli responsibility. Lastly, future aspects and potential uses of nanoparticulated drug systems are outlined.

Targeting cancer cells in the tumor microenvironment: opportunities and challenges in combinatorial nanomedicine

Cancer therapies of the future will rely on synergy between drugs delivered in combination to achieve both maximum efficacy and decreased toxicity. Nanoscale drug delivery vehicles composed of highly tunable nanomaterials ('nanocarriers') represent the most promising approach to achieve simultaneous, cell-selective delivery of synergistic ratios of combinations of drugs within solid tumors. Nanocarriers are currently being used to co-encapsulate and deliver synergistic ratios of multiple anticancer drugs to target cells within solid tumors. Investigators exploit the unique environment associated with solid tumors, termed the tumor microenvironment (TME), to make 'smart' nanocarriers. These sophisticated nanocarriers exploit the pathological conditions in the TME, thereby creating highly targeted nanocarriers that release their drug payload in a spatially and temporally controlled manner. The translational and commercial potential of nanocarrier-based combinatorial nanomedicines in cancer therapy is now a reality as several companies have initiated human clinical trials.