Nowadays successful application of nanoparticles for therapeutic objects needs the effective uptake of them by cells. Hence, studying of the interaction of nanoparticles with cell membrane for effective cellular uptaking seems to be vital and important. Trafficking of lipids, proteins, glucose, and other biomaterials into the cells is possible from two major exocytic and endocytic pathways. The penetration ability of nanoparticles into the cells must be considered in engineering of these particles. Enormous in vivo and in vitro experiments in the field of nanotechnology have confirmed the effect of physiochemistry properties in state of cell-nanoparticles interactions. Thus, the optimization of parameters directly related to physicochemical characteristics through the preparation process seems to be necessary for improving therapeutic effects of nanocarriers. Besides, biological medium and cell division also affect the amount of nanoparticle uptaking into the cells. This study reviews the influence of size, shape, the surface modification of nano particles, medium, and cell division effects on the cellular absorption of drug/gene nanocarriers.

Nanoparticulate drug/gene carriers have gained much attention in the past decades because of their versatile and tunable properties. However, efficacy of the therapeutic agents can be further enhanced using naturally occurring materials‐based nanoparticles. Polysaccharides are an emerging class of biopolymers; therefore, they are generally considered to be safe, non‐toxic, biocompatible and biodegradable. Considering that the target of nanoparticle‐based therapeutic strategies is localization of biomedical agents in subcellular compartments, a detailed understanding of the cellular mechanism involved in the uptake of polysaccharide‐based nanoparticles is essential for safe and efficient therapeutic applications. Uptake of the nanoparticles by the cellular systems occurs with a process known as endocytosis and is influenced by the physicochemical characteristics of nanoparticles such as size, shape and surface chemistry as well as the employed experimental conditions. In this study, we highlight the main endocytosis mechanisms responsible for the cellular uptake of polysaccharide nanoparticles containing drug/gene.

Rivastigmine hydrogen tartrate (RHT), one of the potential cholinesterase inhibitors, has received great attention as a new drug candidate for the treatment of Alzheimer's disease. However, the bioavailability of RHT from the conventional pharmaceutical forms is low because of the presence of the blood brain barrier. The main aim of the present study was to prepare positively charged Eudragit RL 100 nanoparticles as a model scaffold for providing a sustained release profile for RHT. The formulations were evaluated in terms of particle size, zeta potential, surface morphology, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Drug entrapment efficiency and in vitro release properties of lyophilized nanoparticles were also examined. The resulting formulations were found to be in the size range of 118 nm to 154 nm and zeta potential was positive (+22.5 to 30 mV). Nanoparticles showed the entrapment efficiency from 38.40 ± 8.94 to 62.00 ± 2.78%. An increase in the mean particle size and the entrapment efficiency was observed with an increase in the amount of polymer. The FTIR, XRD, and DSC results ruled out any chemical interaction between the drug and Eudragit RL100 polymer. RHT nanoparticles containing low ratio of polymer to drug (4:1) presented a faster drug release and on the contrary, nanoparticles containing high ratio of polymer to drug (10:1) were able to give a more sustained release of the drug. The study revealed that RHT nanoparticles were capable of releasing the drug in a prolonged period of time and increasing the drug bioavailability.

The repair and regeneration of articular cartilage represent important challenges for orthopedic investigators and surgeons worldwide due to its avascular, aneural structure, cellular arrangement, and dense extracellular structure. Although abundant efforts have been paid to provide tissue-engineered grafts, the use of therapeutically cell-based options for repairing cartilage remains unsolved in the clinic. Merging a clinical perspective with recent progress in nanotechnology can be helpful for developing efficient cartilage replacements. Nanomaterials, < 100 nm structural elements, can control different properties of materials by collecting them at nanometric sizes. The integration of nanomaterials holds promise in developing scaffolds that better simulate the extracellular matrix (ECM) environment of cartilage to enhance the interaction of scaffold with the cells and improve the functionality of the engineered-tissue construct. This technology not only can be used for the healing of focal defects but can also be used for extensive osteoarthritic degenerative alterations in the joint. In this review paper, we will emphasize the recent investigations of articular cartilage repair/regeneration via biomaterials. Also, the application of novel technologies and materials is discussed.

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Over the past few years, nasal drug delivery has attracted more and more attentions, and been recognized as the most promising alternative route for the systemic medication of drugs limited to intravenous administration. Many experiments in animal models have shown that nanoscale carriers have the ability to enhance the nasal delivery of peptide/protein drugs and vaccines compared to the conventional drug solution formulations. However, the rapid mucociliary clearance of the drug-loaded nanoparticles can cause a reduction in bioavailability percentage after intranasal administration. Thus, research efforts have considerably been directed towards the development of hydrogel nanosystems which have mucoadhesive properties in order to maximize the residence time, and hence increase the period of contact with the nasal mucosa and enhance the drug absorption. It is most certain that the high viscosity of hydrogel-based nanosystems can efficiently offer this mucoadhesive property. This update review discusses the possible benefits of using hydrogel polymer-based nanoparticles and hydrogel nanocomposites for drug/vaccine delivery through the intranasal administration.

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Many studies have focused on how drugs are formulated in the sol state at room temperature leading to the formation of in situ gel at eye temperature to provide a controlled drug release. Stimuli-responsive block copolymer hydrogels possess several advantages including uncomplicated drug formulation and ease of application, no organic solvent, protective environment for drugs, site-specificity, prolonged and localized drug delivery, lower systemic toxicity, and capability to deliver both hydrophobic and hydrophilic drugs. Self-assembling block copolymers (such as diblock, triblock, and pentablock copolymers) with large solubility variation between hydrophilic and hydrophobic segments are capable of making temperature-dependent micellar assembles, and with further increase in the temperature, of jellifying due to micellar aggregation. In general, molecular weight, hydrophobicity, and block arrangement have a significant effect on polymer crystallinity, micelle size, and in vitro drug release profile. The limitations of creature triblock copolymers as initial burst release can be largely avoided using micelles made of pentablock copolymers. Moreover, formulations based on pentablock copolymers can sustain drug release for a longer time. The present study aims to provide a concise overview of the initial and recent progresses in the design of hydrogel-based ocular drug delivery systems.