Cellular Drug Delivery Research Articles

Preparation and characterization of gadolinium-based thermosensitive liposomes: A potential nanosystem for selective drug delivery to cancer cells

Gadodiamide (Gd-DTPA-BMA) is a gadolinium-based complex, used as a contrast agent in magnetic resonance imaging procedures. Recent studies revealed the capacity of this complex of inducing apoptosis in neoplastic cells. However, a great challenge for its use as an anticancer drug is low cellular internalization and drug delivery systems such as thermosensitive liposomes can be a strategy to overcome these limitations and increase anti-tumor efficacy. In this context, this study aimed to develop, characterize, and assess the cytotoxic activity and selectivity index of thermosensitive liposomes containing Gd-DTPA-BMA. Formulations were prepared by the lipid film hydration method and their physicochemical, morphological, and thermal properties were evaluated. Cell viability was performed 4T1/MDA-MB-231 tumor cells and WI-26 VA4 normal cells. Transmission electron microscopy analyses showed high electron density in the inner core of Gd-DTPA-BMA-loaded liposomes that can be attributed to the Gd-DTPA-BMA, since Gd-loaded nanosystems present low light transmittance and high electron density by this technique. The dynamic light scattering, differential scanning calorimetry, small-angle X-ray scattering, and in vitro release results confirm that the lipid composition was suitable since Tc (temperature of the transition Lβ → Lα) values are in accordance with those reported for thermosensitive liposomes used in the treatment of cancer. The cytotoxic studies against breast cancer cell lines demonstrated that the Gd-DTPA-BMA-loaded liposomes have higher cytotoxicity than free Gd-DTPA-BMA. Moreover, these liposomes presented minimal toxicity in a normal cell line when compared to the free Gd-DTPA-BMA. Therefore, the results of this study suggest that thermosensitive liposomes containing Gd-DTPA-BMA might be a new promising nanocarrier system for breast cancer treatment.

Activating the Cpx response induces tolerance to antisense PNA delivered by an arginine-rich peptide in Escherichia coli

Cell-penetrating peptides (CPPs) are increasingly used for cellular drug delivery in both pro- and eukaryotic cells, and oligoarginines have attracted special attention. How arginine-rich CPPs translocate across the cell envelope, particularly for prokaryotes, is still unknown. Arginine-rich CPPs efficiently deliver antimicrobial peptide nucleic acid (PNA) to its intracellular mRNA target in bacteria. We show that resistance to PNA conjugated to an arginine-rich CPP in Escherichia coli requires multiple genetic modifications and is specific for the CPP part and not to the PNA part. An integral part of the resistance was the constitutively activated Cpx-envelope stress response system (cpx∗), which decreased the cytoplasmic membrane potential. This indicates an indirect energy-dependent uptake mechanism for antimicrobials conjugated to arginine-rich CPPs. In agreement, cpx∗ mutants showed low-level resistance to aminoglycosides and an arginine-rich CPP conjugated to a peptide targeting the DNA sliding clamp, i.e., similar uptake in E. coli for these antimicrobial compounds.

Aptamer-based diagnostic and therapeutic approaches in animals: Current potential and challenges.

Fast and precise diagnosis of infectious and non-infectious animal diseases and their targeted treatments are of utmost importance for their clinical management. The existing biochemical, serological and molecular methods of disease diagnosis need improvement in their specificity, sensitivity and cost and, are generally not amenable for being used as points-of-care (POC) device. Further, with dramatic changes in environment and farm management practices, one should also arm ourselves and prepare for emerging and re-emerging animal diseases such as cancer, prion diseases, COVID-19, influenza etc. Aptamer – oligonucleotide or short peptides that can specifically bind to target molecules – have increasingly become popular in developing biosensors for sensitive detection of analytes, pathogens (bacteria, virus, fungus, prions), drug residues, toxins and, cancerous cells. They have also been proven successful in the cellular delivery of drugs and targeted therapy of infectious diseases and physiological disorders. However, the in vivo application of aptamer-mediated biosensing and therapy in animals has been limited. This paper reviews the existing reports on the application of aptamer-based biosensors and targeted therapy in animals. It also dissects the various modifications to aptamers that were found to be successful in in vivo application of the aptamers in diagnostics and therapeutics. Finally, it also highlights major challenges and future directions in the application of aptamers in the field of veterinary medicine.

Cellular protein markers, therapeutics, and drug delivery strategies in the treatment of diabetes-associated liver fibrosis.

Liver fibrosis is the excessive accumulation of extracellular matrix due to chronic injuries, such as viral infection, alcohol abuse, high-fat diet, and toxins. Liver fibrosis is reversible before it progresses to cirrhosis and hepatocellular carcinoma. Type 2 diabetes significantly increases the risk of developing various complications including liver diseases. Abundant evidence suggests that type 2 diabetes and liver diseases are bidirectionally associated. Patients with type 2 diabetes experience more severe symptoms and accelerated progression of live diseases. Obesity and insulin resistance resulting from hyperlipidemia and hyperglycemia are regarded as the two major risk factors that link type 2 diabetes and liver fibrosis. This review summarizes possible mechanisms of the association between type 2 diabetes and liver fibrosis. The cellular protein markers that can be used for diagnosis and therapy of type 2 diabetes-associated liver fibrosis are discussed. We also highlight the potential therapeutic agents and their delivery systems that have been investigated for type 2 diabetes-associated liver fibrosis.

Oscillatory behavior of microbubbles impacts efficacy of cellular drug delivery

Drug-loaded microbubbles have been proven to be an effective strategy for non-invasive and local drug delivery when combined with ultrasound excitation for targeted drug release. Inertial cavitation is speculated to be a major mechanism for releasing drugs from drug-loaded microbubbles, but it results in lethal cellular pore damage that greatly limits its application. Thus, we investigated the cellular vesicle attachment and uptake to evaluate the efficiency of drug delivery by modulating the behaviors of targeted microbubble oscillation. The efficiency of vesicle attachment on the targeted cell membrane was 36.5 ± 15.9% and 3.8 ± 2.3% under stable and inertial cavitation, respectively. Further, stable cavitation enhanced cell permeability (26.8 ± 3.2%), maintained cell viability (90.8 ± 2.1%), and showed 7.9 ± 1.9-fold enhancement of in vivo vesicle release on tumor vessels. Therefore, our results reveal the ability to improve drug delivery via stable cavitation induced by targeted microbubbles. We propose that this strategy might be suitable for tissue repair or neuromodulation.

Evaluation of cellular response and drug delivery efficacy of nanoporous stainless steel material

ObjectiveVarious surface modification techniques that can further improve the function and usability of stainless steel as a medical device have been reported. In the present study, the physical and biological properties of nanoporous stainless steel as well as its usefulness for drug delivery were assessed.MethodsThe specimen was prepared with a circular disk shape (15 mm in diameter and 1 mm in thickness). The disk was subjected to electropolishing at a constant voltage of 20 V and 10 A for 10 min in an acidic environment (50% H2SO4). Everolimus (EVL) was used as a testing drug for drug-loading capacity of the material surface and release kinetics. The physiobiological properties of the material were assessed using platelet adhesion, and smooth muscle cell (SMC) adhesion, migration, and proliferation assays.ResultsThe surface roughness of the postpolishing group was greater than that of the nonpolishing group. Platelet adhesion and SMC adhesion and migration were inhibited in the postpolishing group compared to those in the prepolishing group. In the postpolishing group, the total amount of EVL on the surface (i.e., drug storage rate) was higher and the drug release rate was lower, with half the amount of the EVL released within 4 days compared with only 1 day for that of the prepolishing group.ConclusionTaken together, this stainless steel with a nanoporous surface could be used as a medical device for controlling cellular responses and carrying drugs.

TEA-assistant synthesis of MOF-74 nanorods for drug delivery and in-vitro magnetic resonance imaging

Zn-MOF-74 nanorods with uniform diameters of about 200 nm were successfully prepared by a triethylamine (TEA) assistant solvothermal method. The effects of TEA on the sizes and morphologies of nanoscale particles were investigated. Guided by this method, bimetallic ZnxMn1-x-MOF-74s were facilely prepared to endow the nanomaterial with magnetic resonance imaging (MRI) ability. Nanoscale Zn0.7Mn0.3-MOF-74 were successfully produced with homogenous Mn dispersion. Magnetic resonance relaxivity studies using clinical MRI equipment proved that Zn0.7Mn0.3-MOF-74 nanoparticles show a satisfactory r1 relaxivity value of 6.5 mM−1 s−1. The saturated DOX loading capacity of Zn0.7Mn0.3-MOF-74 nanocarriers was evaluated to 113 mg g−1. After chitosan (CS) coating, cytotoxicity experiments showed that [email protected]0.7Mn0.3[email protected] nanocomposites featured adequate biotolerability and no interference with cellular metabolism. These results indicated great potential of the bimetallic ZnMn-MOF-74s as new biomedical materials integrating cellular drug delivery with MR imaging applications.

Controlled syntheses of Mg-MOF-74 nanorods for drug delivery

Nanoscale Mg-MOF-74 materials with different sizes have been fabricated by controlling the crystallization process through a two-steps solvothermal method. The obtained samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and nitrogen adsorption properties. The well-shaped Mg-MOF-74 nanorods with sizes of 200 ​nm were chosen for further drug carrier. The saturated loading capacity of Mg-MOF-74 nanorods for an anti-cancer drug of α-cyano-4-hydroxycinnamate (CHC) was evaluated to 625 ​mg ​g−1. After coating by polydopamine (PDA), the cytotoxicity experiments showed that Mg-MOF-74@PDA nanocomposites feature adequate biotolerability and no interference with cellular metabolism. These results indicated great potential of Mg-MOF-74@PDA nanocomposite as a new biomedical material for cellular drug delivery.

Release of functional dexamethasone by intracellular enzymes: A modular peptide-based strategy for ocular drug delivery

Tissue barriers limit drug delivery in the eye. Therefore, retinal diseases are treated with intravitreal injections. Delivery systems with reduced dosing frequency and/or cellular drug delivery properties are needed. We present here a modular peptide-based delivery system for cell targeted release of dexamethasone in the retinal pigment epithelial cells. The peptide–dexamethasone conjugates consist of cell penetrating peptide, enzyme cleavable linker and dexamethasone that is conjugated with hydrazone bond. The conjugates are chemically stable in the vitreous, internalize into the retinal pigment epithelial cells and release dexamethasone intracellularly by enzymatic action of cathepsin D. In vitro binding assay and molecular docking confirm binding of the released dexamethasone fragment to the human glucocorticoid receptor. In vivo rabbit studies show increased vitreal retention of dexamethasone with a peptide conjugate. Modular peptide conjugates are a promising approach for drug delivery into the retinal cells.

Cancer Cell Membrane Camouflaged Semi-Yolk@Spiky-Shell Nanomotor for Enhanced Cell Adhesion and Synergistic Therapy.

Cell adhesion of nanosystems is significant for efficient cellular uptake and drug delivery in cancer therapy. Herein, a near-infrared (NIR) light-driven biomimetic nanomotor is reported to achieve the improved cell adhesion and cellular uptake for synergistic photothermal and chemotherapy of breast cancer. The nanomotor is composed of carbon@silica (C@SiO2 ) with semi-yolk@spiky-shell structure, loaded with the anticancer drug doxorubicin (DOX) and camouflaged with MCF-7 breast cancer cell membrane (i.e.,mC@SiO2 @DOX). Such biomimetic mC@SiO2 @DOX nanomotors display efficient self-thermophoretic propulsion due to a thermal gradient generated by asymmetrically spatial distribution. Moreover, the MCF-7 cancer cell membrane coating can remarkably reduce the bioadhesion of nanomotors in biological medium and exhibit highly specific self-recognition of the source cell line. The combination of effective propulsion and homologous targeting dramatically improves cell adhesion and the resultant cellular uptake efficiency in vitro from 26.2% to 67.5%. Therefore, the biomimetic mC@SiO2 @DOX displays excellent synergistic photothermal and chemotherapy with over 91% MCF-7 cell growth inhibition rate. Such smart design of the fuel-free, NIR light-powered biomimetic nanomotor may pave the way for the application of self-propelled nanomotors in biomedicine.

Targeting of Perforin Inhibitor into the Brain Parenchyma Via a Prodrug Approach Can Decrease Oxidative Stress and Neuroinflammation and Improve Cell Survival

The cytolytic protein perforin has a crucial role in infections and tumor surveillance. Recently, it has also been associated with many brain diseases, such as neurodegenerative diseases and stroke. Therefore, inhibitors of perforin have attracted interest as novel drug candidates. We have previously reported that converting a perforin inhibitor into an L-type amino acid transporter 1 (LAT1)-utilizing prodrug can improve the compound’s brain drug delivery not only across the blood–brain barrier (BBB) but also into the brain parenchymal cells: neurons, astrocytes, and microglia. The present study evaluated whether the increased uptake into mouse primary cortical astrocytes and subsequently improvements in the cellular bioavailability of this brain-targeted perforin inhibitor prodrug could enhance its pharmacological effects, such as inhibition of production of caspase-3/-7, lipid peroxidation products and prostaglandin E2 (PGE2) in the lipopolysaccharide (LPS)-induced neuroinflammation mouse model. It was demonstrated that increased brain and cellular drug delivery could improve the ability of perforin inhibitors to elicit their pharmacological effects in the brain at nano- to picomolar levels. Furthermore, the prodrug displayed multifunctional properties since it also inhibited the activity of several key enzymes related to Alzheimer’s disease (AD), such as the β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE), and most probably also cyclooxygenases (COX) at micromolar concentrations. Therefore, this prodrug is a potential drug candidate for preventing Aβ-accumulation and ACh-depletion in addition to combatting neuroinflammation, oxidative stress, and neural apoptosis within the brain.Graphical abstract

One-/Two-Photon Excited Cell Membrane Imaging and Tracking by a Photoactive Nanocage.

Cell membrane imaging by predesigned molecular and supramolecular photoluminescence probes is of great importance in understanding the nano-biointeractions for potential applications in cellular tracking, drug delivery, cancer diagnosis, and treatment. Herein, we report an effective strategy for cell membrane imaging in both living cell and tissue levels on the basis of a multifunctional nanocage (MOC-16) integrating one-/two-photon active phosphorescence, high charges, balanced hydrophobicity/lipophilicity, and proton sensitivity attributes. The intrinsic optical characters, including strong one-/two-photon excitation and pH-dependent red emission, make MOC-16 powerful optical probes for membrane imaging in living cell and tissue levels under both visible and near-infrared irradiations. Meanwhile, the highly positive charges of +28 endow MOC-16 with adequate water solubility and deprotonation ability while still maintaining its hydrophobicity, thus enabling balanced hydrophobic-lipophilic interactions at the nano-biointerface to facilitate a pH-dependent membrane absorption within the biological pH range of 5.3-7.4. However, the low-charged RuL3 metalloligand or polyethylene glycol (PEG)-modified MOC-16PEG with less hydrophobicity cannot offer enough nano-biointeractions for cell membrane tracking. These findings advance the fundamental understanding of nano-biointerface interactions of MOCs with cell membranes and provide further guidance in their biological applications.

Erythrocyte as novel cellular drug delivery system

Nowadays so many carrier systems are used for delivery of drug or any other therapeutic agent to specific tissues or cells for achieving desired therapeutic efficacy. Using drug delivery systems can improve action of therapeutic agent and reduce their toxicity. As a novel approach the erythrocyte or red blood cells are used for drug delivery. The resealed erythrocyte is a cellular carrier have more advantage than other carrier system. Based on various studies found that erythrocyte have greater potential in delivery of biopharmaceuticals, therapeutically significant peptides and proteins, nucleic acid-based biological, antigens, anticancer drug and vaccines. The main problem obtain in case of existing carrier systems are biocompatibility of carrier and its degradation products. The biocompatibility, non-pathogenicity, non-immunogenicity and biodegradability make erythrocyte unique and useful carriers. They also possess longer circulation half-life and zero order drug release kinetics. Resealed erythrocyte carriers have certain impact among the activity of certain therapeutic agent like anti-inflammatory drugs, steroids, chemotherapeutic agents by reducing their side effect upon incorporation with these carriers. The general preparation step of resealed erythrocyte involve separation of erythrocyte from blood the organism of interest and using different methods the erythrocyte broken and the therapeutic agent or drug entrapped into the erythrocyte. This review article highlights the characteristics, isolation techniques of erythrocyte, preparation method, evaluation, application of resealed erythrocyte as carrier in drug delivery systems.

Influence of Size and Cross-Linking Density of Microgels on Cellular Uptake and Uptake Kinetics

The unique pH and temperature responsiveness of PNIPAM-based microgels make them a promising target for novel biomedical applications such as cellular drug delivery systems. However, we lack a comprehensive understanding of how the physicochemical properties of microgels relate to their interaction with cells. Here, we show that HEK293T cells take up PNIPAM-based microgels on a second-to-minute time scale. Uptake rates are determined by microgel size and cross-linker content. Using fluorescence confocal live-cell microscopy, we observe microgel uptake in real time and describe cellular uptake kinetics. Experiments reveal that small and less cross-linked microgels show faster uptake kinetics than microgels of larger size or higher cross-linker content. Only microgels that are larger than 800 nm in diameter and have cross-linking contents of 10-15 mol % do not show translocation into cells. Together, these results provide insight into microgel-cell interactions and generate quantitative information on the deterministic role of microgel architecture-i.e., size and rigidity-for uptake by a prototypical human cell line.

Divalent Cations and Lipid Composition Modulate Membrane Insertion and Cancer-Targeting Action of pHLIP

The pH-Low Insertion Peptide (pHLIP) has emerged as an important tool for targeting cancer cells. It has been assumed that its targeting mechanism depends solely on the mild acidic environment surrounding tumors. Here, we examine the role of the two predominant extracellular divalent cations, Ca2+ and Mg2+, on pHLIP's cellular targeting, insertion, and drug delivery. Using a combination of cellular and spectroscopic techniques we demonstrate that physiologically-relevant concentrations of either cation drastically promote the interaction and insertion of pHLIP.

Anticancer Activity of ZnO Nanoparticles against Human Small-Cell Lung Cancer in an Orthotopic Mouse Model.

Small-cell lung cancer, a highly malignant form of lung cancer, often responds to first-line treatments but relapses in most cases with resistance to further treatments. We tested zinc oxide (ZnO) nanoparticles against small-cell lung cancer and other cancer cell lines, in light of reported anticancer effects in vitro Because of a strong safety record, ZnO nanoparticles are frequently used in biomedical research, including in cellular imaging and drug delivery, and have been used for many years in several commercial products such as skin care agents. Strikingly, ZnO nanoparticles were genotoxic against small-cell lung cancer cells, resulting in low viability, even in cells orthotopically grafted onto mouse models. However, the nanoparticles were less cytotoxic against normal lung-derived cells and did not elicit observable adverse effects after intravenous administration. ZnO nanoparticles were also found to induce highly reactive oxygen species and DNA leakage from nuclei. This study is the first comprehensive evaluation of the anticancer effects of ZnO nanoparticles in vitro and in vivo and highlights new therapeutic opportunities against small-cell lung cancer.

Novel Composite Nanocarriers

Need for materials with high biocompatible properties have led to the development of prodrug-decorated nanoparticles. The structure of present nanostructures consists of the hydrophobic core and hydrophilic shell. The shell acts as an external envelop which enhances the colloidal stability of dispersion which protects the prodrug of the nanoparticles from photo- and thermal-initiated degradation. The composite nanoparticles coated by organic shells with functional groups were considered to govern the covalent immobilization of therapeutics/biomolecules. The nanoparticles with unique physiochemical properties may be useful as biosensors in living whole cells. The enhanced cellular drug delivery to cancer cell lines via nanoconjugates revealed that smart nanoparticles are an effective tool for transporting and delivering drugs.

PH-Triggered geometrical shape switching of a cationic peptide nanoparticle for cellular uptake and drug delivery

The geometry of nanoparticles plays an important role in their performance as drug carriers. However, the pH-triggered geometrical shape switching of a cationic peptide consisting of isoleucine and lysine is seldom reported. In this work, we designed a cationic peptide with acid reactivity that can be loaded with the poorly soluble antitumor drug (doxorubicin (DOX)) to enhance tumor cell uptake and drug delivery. In a weakly acidic environment, a large portion of random coil structures formed, which subsequently led to nanoparticle destruction and rapid DOX release. In vitro studies demonstrated that this cationic peptide exhibits low toxicity to normal cells. The amount of DOX-encapsulating peptide nanoparticles taken up by tumor cells was greater than that taken up by normal cells. Our results indicated that the use of a weakly acidic microenvironment to induce geometric shape switching in drug-loaded peptide nanoparticles should be a promising strategy for antitumor drug delivery.

Peptide-based delivery vectors with pre-defined geometrical locks.

Design of peptide-based targeted delivery vectors with attributes of specificity and selective cellular targeting by fixing their topology and resulting electrostatic fingerprint is the objective of this study. We formulated our peptide design platform by utilizing the possibilities of side-chain induced geometric restrictions in a typical peptide molecule. Conceptually, we locked the conformation of the RGD/NGR motif of tumor homing peptides (THPs) by mutating glycine in these motifs with d-proline and tailed the peptides with a syndiotactic amphipathic segment for cellular penetration. The designed peptides were synthesized, characterized, and tested in vitro on various cell lines, including breast cancer (MDA-MB-231), cervical cancer (HeLa), osteosarcoma (U2-OS) and non-cancer mammary epithelial cells (MCF-10A), by flow cytometry and confocal microscopy. The results showed differential cellular uptake in different cell types, as a result of the distinct electrostatic fingerprint encoded in their design. The uptake of serum pre-treated peptides by cells reveals the retention of peptide activity even after the incubation with serum. In addition, peptide-methotrexate (MTX) conjugates compared to the methotrexate drug showed enhanced apoptotic cell death in MTX-resistant MDA-MB-231 cells, indicating the increase in MTX bioavailability.

An Efficient Routing Scheme for Intrabody Nanonetworks Using Artificial Bee Colony Algorithm

An Intrabody Nanonetwork (IBNN) is constituted by nanoscale devices that are implanted inside the human body for monitoring of physiological parameters for disease diagnosis and treatment purposes. The extraordinary accuracy and precision of these nanoscale devices in cellular level disease diagnosis and drug delivery are envisioned to advance the traditional healthcare system. However, the feature constraints of these nanoscale devices, such as inadequate energy resources, topology-unawareness, and limited computational power, challenges the development of energy-efficient routing protocol for IBNNs. The presented work concentrates on the primary limitations and responsibilities of IBNNs and designs a routing protocol that incorporates characteristics of Exponential Weighted Moving Average (EWMA) Based Opportunistic Data Transmission (EWMA-ODT) and Artificial Colony Algorithm Based Query Response Transmission (ABC-QRT) approaches for efficiently handling the routing challenges of IBNNs. In EWMA-ODT, the moving Nano Biosensors (NBSs) employ the EWMA method attributes to aggregate detected data by assigning high weightage to the recent detected information. Later, the aggregated data is transmitted to the Nano Router (NR) when the direct data transmission opportunity is available, the reception of aggregated briefs NR about the condition of the network after the last successful interaction with minimum energy consumption. Whereas, the ABC-QRT approach introduces the ABC algorithm for the selection of those optimal NBSs that have maximum fitness value for satisfying the data transmission demand of the external healthcare system with minimal traffic overhead. The simulation results validate that the joint contribution of these approaches enhances IBNNs lifetime and reduces end-to-end delay as compared to the flooding scheme.