Quantum dot/glycol chitosan fluorescent nanoconjugates

Nanocarriers based novel and effective drug delivery system

Nanotechnology has ultimately come into the domain of drug delivery. Nanosystems for delivery of drugs are promptly emerging science utilizing different nanoparticles as carriers. Biocompatible and stable nanocarriers are novel diagnosis tools or therapy agents for explicitly targeting locates with controllable way. Nanocarriers propose numerous advantages to treat diseases via site-specific as well as targeted delivery of particular therapeutics. In recent times, there are number of outstanding nanocarriers use to deliver bio-, chemo-, or immuno- therapeutic agents to obtain effectual therapeutic reactions and to minimalize unwanted adverse-effects. Nanoparticles possess remarkable potential for active drug delivery. Moreover, conjugation of drugs with nanocarriers protects drugs from metabolic or chemical modifications, through their way to targeted cells and hence increased their bioavailability. In this review, various systems integrated with different types of nanocarriers (inorganic. organic, quantum dots, and carbon nanotubes) having different compositions, physical and chemical properties have been discussed for drug delivery applications.

Metal-Free Organo-Theranostic Nanosystem with High Nitroxide Stability and Loading for Image-Guided Targeted Tumor Therapy

The desire for all-organic-composed nanoparticles (NPs) of considerable biocompatibility to simultaneously diagnose and treat cancer is undeniably interminable. Heretofore, metal-based agents dominate the landscape of available magnetic resonance imaging (MRI) contrast agents and photothermal therapeutic agents, but with associated metal-specific downsides. Here, an all-organic metal-free nanoprobe, whose appreciable biocompatibility is synergistically contributed by its tetra-organo-components, is developed as a viable alternative to metal-based probes for MRI-guided tumor-targeted photothermal therapy (PTT). This rationally entails a glycol chitosan (GC)-linked polypyrrole (PP) nanoscaffold that provides abundant primary and secondary amino groups for amidation with the carboxyl groups in a nitroxide radical (TEMPO) and folic acid (FA), to obtain GC-PP@TEMPO-FA NPs. Advantageously, the appreciably benign GC-PP@TEMPO-FA features high nitroxide loading (r₁ = 1.58 mM^-1 s^-1) and in vivo nitroxide-reduction resistance, prolonged nitroxide-systemic circulation times, appreciable water dispersibility, potential photodynamic therapeutic and electron paramagnetic resonance imaging capabilities, considerable biocompatibility, and ultimately achieves a 17 h commensurate MRI contrast enhancement. Moreover, its GC component conveys a plethora of PP to tumor sites, where FA-mediated tumor targeting enables substantial NP accumulation with consequential near-complete tumor regression within 16 days in an MRI-guided PTT. The present work therefore promotes the engineering of organic-based metal-free biocompatible NPs in synergism, in furtherance of tumor-targeted image-guided therapy.

A Hybrid Organo-Nanotheranostic Platform of Superlative Biocompatibility for Near-Infrared-Triggered Fluorescence Imaging and Synergistically Enhanced Ablation of Tumors

The quest for an all-organic nanosystem with negligible cytotoxicity and remarkable in vivo tumor theranostic capability is inescapably unending. Hitherto, the landscape of available photothermal agents is dominated by metal-based nanoparticles (NPs) with attendant in vivo negatives. Here, an all-organic-composed theranostic nanosystem with outstanding biocompatibility for fluorescence image-guided tumor photothermal therapy, and as a potential alternative to metal-based photothermal agents is developed. This is rationally achieved by compartmentalizing indocyanine green (ICG) in glycol chitosan (GC)-polypyrrole (PP) nanocarrier to form hybrid ICG@GC-PP NPs (≈65 nm). The compartmentalization strategy, alongside the high photothermal conversion ability of PP jointly enhances the low photostability of free ICG. Advantageously, ICG@GC-PP is endowed with an impeccable in vivo performance by the well-known biocompatibility track records of its individual tri organo-components (GC, PP, and ICG). As a proof of concept, ICG@GC-PP NPs enables a sufficiently prolonged tumor diagnosis by fluorescence imaging up to 20 h post-injection. Furthermore, owing to the complementary heating performances of PP and ICG, ICG@GC-PP NPs-treated mice by one-time near-infrared irradiation exhibit total tumor regression within 14 days post-treatment. Therefore, leveraging the underlying benefits of this study will help to guide the development of new all-organic biocompatible systems in synergism, for safer tumor theranostics.

All-in-one microfluidic assembly of insulin-loaded pH-responsive nano-in-microparticles for oral insulin delivery

Here, a continuous two-step glass-capillary microfluidic technique to produce a multistage oral insulin delivery system is reported. This system represents a promising alternative for the common protein/peptide-loaded liposome formulations.

Chitosan-based (Nano)materials for Novel Biomedical Applications

Chitosan-based nanomaterials have attracted significant attention in the biomedical field because of their unique biodegradable, biocompatible, non-toxic, and antimicrobial nature. Multiple perspectives of the proposed antibacterial effect and mode of action of chitosan-based nanomaterials are reviewed. Chitosan is presented as an ideal biomaterial for antimicrobial wound dressings that can either be fabricated alone in its native form or upgraded and incorporated with antibiotics, metallic antimicrobial particles, natural compounds and extracts in order to increase the antimicrobial effect. Since chitosan and its derivatives can enhance drug permeability across the blood-brain barrier, they can be also used as effective brain drug delivery carriers. Some of the recent chitosan formulations for brain uptake of various drugs are presented. The use of chitosan and its derivatives in other biomedical applications is also briefly discussed.

Optical Recognition of Ammonia and Amine Vapor Using "Turn-on" Fluorescent Chitosan Nanoparticles Imprinted on Cellulose Strips

A practical fluorescent test dipstick for an efficient recognition of ammonia and amines vapors was developed. The prepared testing strip was based on a composite of molecularly imprinted chitosan nanoparticles, supported on cellulose paper assay, with artificial fluorescent receptor sites for ammonia/amines recognition in aqueous and gaseous phases. A modified chitosan nanoparticles containing fluorescein molecules, were successfully prepared and employed on cellulose paper strip creating fluorescent cellulose (FL-Cell) to act as "turn-on" fluorescent sensor for sensing and determining ammonia and organic amine vapor. We employed chitosan nanoparticles that had fluorescein incorporated as the fluorescent probe molecule, with a readout limit achieved for aqueous ammonia as low as 280 ppm at room temperature and atmospheric pressure. The sensor responded linearly relying on the aqueous ammonia concentration in the range of 0.13-280 ppm. The chromogenic fluorescent cellulose platform response depended on the acid-base characteristic effects of the fluorescein probe. The protonated form of fluorescein molecules immobilized within the chitosan nanoparticles were in a nanoenvironment demonstrating only weak fluorescence. When binding to ammonia/amine vapor, the fluorescein active sites were deprotonated and exhibited higher "turned-on" fluorescence as a result of exposure to those alkaline species. The simple fabrication and abovementioned characteristics of such fluorescent chitosan nanoparticles are such that they should be applicable for monitoring of ammonia/amines in either aqueous or vapor states. We studied the distribution of the fluorescent chitosan onto paper sheets fabricated from bleached bagasse pulp and coated with two different thicknesses of a fluorescent nanochitosan and blank nanochitosan solutions. A thin fluorescent nanochitosan layer was created on the surface of cellulose strips using an applicator. Its distribution was assessed by scanning electron microscopic (SEM) and transmission electron microscopic (TEM) analysis as well as Fourier-transform infrared spectroscopic (FT-IR) measurements. The mechanical properties were also tested. The exploitation of this "turn-on" fluorescence sensor invented platform should be amenable to different situations where determination of ammonia/amine vapor or aqueous solution is required.

Chitosan nanoparticles functionalized with β-cyclodextrin: a promising carrier for botanical pesticides

Carvacrol and linalool are natural compounds extracted from plants and are known for their insecticidal and repellent activities, respectively. However, their low aqueous solubility, high photosensitivity, and high volatility restrict their application in the control of agricultural pests. The encapsulation of volatile compounds can be an effective way of overcoming such problems. Inclusion complexes between beta-cyclodextrin (β-CD) and carvacrol (CVC) or linalool (LNL) were investigated. Inclusion complexes were prepared by the kneading method. Both complexes presented 1:1 host:guest stoichiometry and the highest affinity constants were observed at 20 °C for both molecules. The nanoparticles containing carvacrol and linalool had mean diameters of 175.2 and 245.8 nm, respectively and high encapsulation efficiencies (<90%) were achieved for both compounds. Biological assays with mites (Tetranychus urticae) showed that the nanoparticles possessed repellency, acaricidal, and oviposition activities against this organism. Nanoencapsulated carvacrol and linalool were significantly more effective in terms of acaricidal and oviposition activities, while the unencapsulated compounds showed better repellency activity. The nanoformulations prepared in this study are good candidates for the sustainable and effective use of botanical compounds in agriculture, contributing to the reduction of environmental contamination, as well as promoting the effective control of pests in agriculture.

Visible Light-Cured Glycol Chitosan Hydrogel Containing a Beta-Cyclodextrin-Curcumin Inclusion Complex Improves Wound Healing In Vivo

Scarless wound healing is ideal for patients suffering from soft tissue defects. In this study, we prepared a novel wet dressing (β-CD-ic-CUR/GC) based on the visible light-cured glycol chitosan (GC) hydrogel and inclusion complex between beta-cyclodextrin (β-CD) and curcumin (CUR). We also evaluated its efficacy in the acceleration of wound healing as compared to that of CUR-loaded GC (CUR/GC). The conjugation of glycidyl methacrylate (GM) to GC for photo-curing was confirmed by ¹H-NMR measurement, and the photo-cured GC hydrogel was characterized by the analyses of rheology, swelling ratio, SEM and degradation rate. After visible light irradiation, the surface/cross-sectional morphologies and storage (G′)/loss (G′′) moduli revealed the formation of hydrogel with interconnected porosity. The dressing β-CD-ic-CUR/GC exhibited a controlled release of 90% CUR in a sustained manner for 30 days. On the other hand, CUR/GC showed CUR release of 16%. β-CD acted as an excipient in improving the water-solubility of CUR and affected the release behavior of CUR. The in vivo animal tests including measurement of the remaining unhealed wound area and histological analyses showed that β-CD-ic-CUR/GC may have potential as a wet dressing agent to enhance soft tissue recovery in open fractures.

The Research and Applications of Quantum Dots as Nano-Carriers for Targeted Drug Delivery and Cancer Therapy

Quantum dots (QDs), nano-carriers for drugs, can help realize the targeting of drugs, and improve the bioavailability of drugs in biological fields. And, a QD nano-carrier system for drugs has the potential to realize early detection, monitoring, and localized treatments of specific disease sites. In addition, QD nano-carrier systems for drugs can improve stability of drugs, lengthen circulation time in vivo, enhance targeted absorption, and improve the distribution and metabolism process of drugs in organization. So, the development of QD nano-carriers for drugs has become a hotspot in the fields of nano-drug research in recent years. In this paper, we review the advantages and applications of the QD nano-carriers for drugs in biological fields.

Glycol chitosan/nanohydroxyapatite biocomposites for potential bone tissue engineering and regenerative medicine

In the last few decades, research on biocomposite nanomaterials has grown exponentially due to the global demand for novel solutions in bone tissue engineering and repair. In the present study, it is reported the design and synthesis of biocomposites based on glycol chitosan (GLY-CHI) matrices incorporated with nano-hydroxyapatite particles (nHA) produced via an eco-friendly chemical colloidal process in water media followed by solvent casting and evaporation methods at room temperature. The structure, morphology, and crystallinity of the components and biocomposites were extensively characterized by light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), wavelength dispersive X-ray fluorescence spectroscopy (WD-XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray micro-computed tomography analysis (μCT). Furthermore, cytotoxicity and cell viability tests were performed on three cell lines using a 3-(4,5-dimethylthiazol-2yl) 2,5-diphenyl tetrazolium bromide (MTT) assay, an alkaline phosphatase (ALP) activity test, and LIVE/DEAD^® assays. The results demonstrated that the GLY-CHI ligand played a major role in the nucleation, growth and colloidal stabilization of calcium phosphate particles at nanoscale dimensions with a narrow distribution and average size of 74±15nm. The FTIR spectroscopy associated with the XRD results indicated that nanosized hydroxyapatite (nHA) was the predominant calcium phosphate phase produced in the colloidal processing route. In addition, the X-ray micro-CT analysis of the nanocomposite membranes showed that nHA particles were homogenously dispersed in the glycol-chitosan polymeric matrix. Moreover, according to the in vitro bioassays, the biocomposites showed an adequate cell viability response and non-cytotoxic behavior toward osteoblastic-like (SAOS) and embryonic cell lines (HEK293T). Finally, the results of osteogenic differentiation tests demonstrated that the nHA/GLY-CHI composites are osteoinductive for human bone marrow mesenchymal stem cells (HBMS), which can be envisioned for prospective use in tissue engineering (e.g., bone, cartilage and periodontal) applications.