Paclitaxel-incorporated nanoparticles of hydrophobized polysaccharide and their antitumor activity

Dextran-Cholesterol Carrier Encapsulated Efficient Photosensitizer for the Photodynamic Killing of Cancer Cells

Selective photodynamic therapy (PDT) for cancer cells is more efficient and much safer. Most selective PDTs are realized by antigene-biomarker or peptide-biomarker interactions. Here, we modified dextran with hydrophobic cholesterol as a photosensitizer carrier to selectively target cancer cells, including colon cancer cells, and fulfilled selective PDT. The photosensitizer was designed with regular Aggregation-Induced Emission (AIE) units, including triphenylamine and 2-(3-cyano-4,5,5-trimethylfuran-2-ylidene)propanedinitrile. The AIE units can help to decrease the quenching effect in the aggregate state. The efficiency of the photosensitizer is further improved via the heavy atom effect after bromination modification. We found that the obtained photosensitizer nanoparticles could selectively target and ablate cancer cells after encapsulation into the dextran-cholesterol carrier. This study indicates that the polysaccharide-based carrier may have potential for cancer-targeting therapy beyond expectations.

Nanoparticles loaded with pharmacologically active plant-derived natural products: Biomedical applications and toxicity

Pharmacologically active natural products have played a significant role in the history of drug development. They have acted as sources of therapeutic drugs for various diseases such as cancer and infectious diseases. However, most natural products suffer from poor water solubility and low bioavailability, limiting their clinical applications. The rapid development of nanotechnology has opened up new directions for applying natural products and numerous studies have explored the biomedical applications of nanomaterials loaded with natural products. This review covers the recent research on applying plant-derived natural products (PDNPs) nanomaterials, including nanomedicines loaded with flavonoids, non-flavonoid polyphenols, alkaloids, and quinones, especially their use in treating various diseases. Furthermore, some drugs derived from natural products can be toxic to the body, so the toxicity of them is discussed. This comprehensive review includes fundamental discoveries and exploratory advances in natural product-loaded nanomaterials that may be helpful for future clinical development.

Polyhydroxyalkanoate Decelerates the Release of Paclitaxel from Poly(lactic-co-glycolic acid) Nanoparticles

Biodegradable nanoparticles (NPs) are preferred as drug carriers because of their effectiveness in encapsulating drugs, ability to control drug release, and low cytotoxicity. Although poly(lactide co-glycolide) (PLGA)-based NPs have been used for controlled release strategies, they have some disadvantages. This study describes an approach using biodegradable polyhydroxyalkanoate (PHA) to overcome these challenges. By varying the amount of PHA, NPs were successfully fabricated by a solvent evaporation method. The size range of the NPS ranged from 137.60 to 186.93 nm, and showed zero-order release kinetics of paclitaxel (PTX) for 7 h, and more sustained release profiles compared with NPs composed of PLGA alone. Increasing the amount of PHA improved the PTX loading efficiency of NPs. Overall, these findings suggest that PHA can be used for designing polymeric nanocarriers, which offer a potential strategy for the development of improved drug delivery systems for sustained and controlled release.

Role of Polysaccharides Mimetic Components in Targeted Cancer Treatment

Organic or inorganic compounds are synthesized or formulated in a manner that they completely show their therapeutic actions like as a natural polysaccharide in the body. Polysaccharides, the major type of natural polymers, are efficiently biologically active, non-toxic, hydrophilic, and biodegradable and show various properties. In this manuscript, the main focus is on delivering anticancer drugs with the help of mimetic components of polysaccharides. All data collected for this manuscript was from PubMed, Elsevier, Taylor, and Francis Bentham science journals. Most chemotherapeutics are therapeutically toxin to the human body, have a narrow therapeutic index, sluggish pharmaceutical delivery mechanisms, and are poorly soluble in water. The use of mimetic components of polysaccharides leads to the enhancement of the solubility of drugs in the biological environment. The manuscript summarizes the use of mimetic components of polysaccharides along with anticancer agents which are capable to inhibit the growth of cancerous cells in the body which shows lesser adverse effects in the biological system compared to other therapies.

Eco-friendly synthesis of phthalate angico gum towards nanoparticles engineering using Quality by Design (QbD) approach

We developed a new hydrophobic polymer based on angico gum (AG), and we produced new nanoparticles to expand the applications of natural polysaccharides in nanomedicine. Phthalate angico gum (PAG) was characterized by ¹H NMR, FTIR, elementary analysis, solubility, XRD, and TG. PAG was a hydrophobic and semi-crystalline material, a relevant characteristic for drug delivery system applications. As a proof of concept, nevirapine (NVP) was selected for nanoparticles development. Plackett-Burman's experimental design was used to understand the influence of several factors in nanoparticles production. PAG proved to be a versatile material for producing nanoparticles with different characteristics. Optimized nanoparticles were produced using desirability parameters. NVP-loaded PAG nanoparticles formulation showed 202.1 nm of particle size, 0.23 of PDI, -17.1 of zeta potential, 69.8 of encapsulation efficiency, and promoted modified drug release for 8 h. Here we show that PAG presents as a promising biopolymer for drug delivery systems.

Hydrophobically Grafted Pullulan Nanocarriers for Percutaneous Delivery: Preparation and Preliminary In Vitro Characterisation

Polymeric colloidal nanocarriers formulated from hydrophobically grafted carbohydrates have been the subject of intensive research due to their potential to increase the percutaneous penetration of hydrophilic actives. To this goal, a series of hydrophobically grafted pullulan (BMO-PUL) derivatives with varying degree of grafting (5–64%) was prepared through functionalisation with 2-(butoxymethyl)oxirane. The results demonstrated that monodispersed BMO-PUL nanocarriers (size range 125–185 nm) could be easily prepared via nanoprecipitation; they exhibit close-to-spherical morphology and adequate stability at physiologically relevant pH. The critical micellar concentration of BMO-PUL was found to be inversely proportional to their molecular weight (Mw) and degree of grafting (DG), with values of 60 mg/L and 40 mg/L for DG of 12.6% and 33.8%, respectively. The polymeric nanocarriers were loaded with the low Mw hydrophilic active α-arbutin (16% loading), and the release of this active was studied at varying pH values (5 and 7), with a slightly faster release observed in acidic conditions; the release profiles can be best described by a first-order kinetic model. In vitro investigations of BMO-PUL nanocarriers (concentration range 0.1–4 mg/mL) using immortalised skin human keratinocytes cells (HaCaT) evidenced their lack of toxicity, with more than 85% cell viability after 24 h. A four-fold enhance in arbutin permeation through HaCaT monolayers was recorded when the active was encapsulated within the BMO-PUL nanocarriers. Altogether, the results obtained from the in vitro studies highlighted the potential of BMO-PUL nanocarriers for percutaneous delivery applications, which would warrant further investigation in vivo.

The Potential of a Site-Specific Delivery of Thiamine Hydrochloride as a Novel Insect Repellent Exerting Long-Term Protection on Human Skin: In-vitro, Ex-vivo Study and Clinical Assessment

Thiamine hydrochloride (TH) was thought to exert a good insect repellent activity. The purpose of this work was to develop a formulation that releases TH in sustained regimen on human skin. Long lasting protection against mosquito bites was achieved. Pullulan acetate (PA) was used to prepare TH nanospheres. Optimal system was incorporated in Pluronic® hydrogel. Formulae were tested for in-vitro release and ex-vivo permeation. Complete protection time (CPT) was done adopting Kaplan-Meier survival function for the synthetic repellent (DEET), TH solution and nanospheres in hydrogel. Release profile of TH solution, nanospheres and nanosphere-loaded hydrogel (DG) demonstrated an added effect of DG, where t _1/2 was 11.2 ± 1.4 h. SEM for DG showed homogenous dispersion of nanospheres inside the matrix of the gel. Ex-vivo permeation showed only 0.761 ± 0.04% of TH in hydrogel permeated the skin after 12 h, while 44.98 ± 3.2% permeated when TH solution was applied. Clinical study revealed a significant difference in CPT between TH solution with either DEET or (DG) (p<0.05), and no significant difference between DEET and DG with CPT 400 ± 31 and 360 ± 18 min, respectively (P > 0.05). The high efficacy of TH-loaded hydrogel rendered it a successful alternative for DEET, offering long protection against mosquito bites.

Nanoparticles Based on Hydrophobic Polysaccharide Derivatives-Formation Principles, Characterization Techniques, and Biomedical Applications

Polysaccharide (PS) nanoparticles (NP) are fascinating materials that combine huge application potential with the unique beneficial features of natural biopolymers. Different types of PS-NP can be distinguished depending on the basic preparation principles (top-down vs bottom-up vs coating of nanomaterials) and the material from which they are obtained (native PS vs chemically modified PS derivatives vs nanocomposites). This review provides a comprehensive overview of an approach towards PS-NP that has gained rapidly increasing interest within the last decade; the nanoself-assembling of hydrophobic PS derivatives. This facile process is easy to perform and offers a broad structural diversity in terms of the PS backbone and the additional functionalities that can be introduced. Fundamental principles of different NP preparation techniques along with useful characterization methods are presented in this work. A comprehensive summary of PS-NP prepared by different techniques and with various PS backbones and types/amounts of hydrophobic substituents is given. The intention is to demonstrate how different parameters determine the size, size distribution, and zeta-potential of the particles. Moreover, application trends in biomedical areas are highlighted in which tailored functional PS-NP are evaluated and constantly developed further.

Spotlight on 17-AAG as an Hsp90 inhibitor for molecular targeted cancer treatment

Hsp90 is a ubiquitous chaperone with important roles in the organization and maturation of client proteins that are involved in the progression and survival of cancer cells. Multiple oncogenic pathways can be affected by inhibition of Hsp90 function through degradation of its client proteins. That makes Hsp90 a therapeutic target for cancer treatment. 17-allylamino-17-demethoxy-geldanamycin (17-AAG) is a potent Hsp90 inhibitor that binds to Hsp90 and inhibits its chaperoning function, which results in the degradation of Hsp90's client proteins. There have been several preclinical studies of 17-AAG as a single agent or in combination with other anticancer agents for a wide range of human cancers. Data from various phases of clinical trials show that 17-AAG can be given safely at biologically active dosages with mild toxicity. Even though 17-AAG has suitable pharmacological potency, its low water solubility and high hepatotoxicity could significantly restrict its clinical use. Nanomaterials-based drug delivery carriers may overcome these drawbacks. In this paper, we review preclinical and clinical research on 17-AAG as a single agent and in combination with other anticancer agents. In addition, we highlight the potential of using nanocarriers and nanocombination therapy to improve therapeutic effects of 17-AAG.

Novel Delivery of Mitoxantrone with Hydrophobically Modified Pullulan Nanoparticles to Inhibit Bladder Cancer Cell and the Effect of Nano-drug Size on Inhibition Efficiency

Reducing the dosage of chemotherapeutic drugs via enhancing the delivery efficiency using novel nanoparticles has great potential for cancer treatment. Here, we focused on improving mitoxantrone delivery by using cholesterol-substituted pullulan polymers (CHPs) and selected a suitable nano-drug size to inhibit the growth of bladder cancer cells. We synthesized three kinds of CHPs, named CHP-1, CHP-2, CHP-3. Their chemical structures were identified by NMR, and the degree of cholesterol substitution was 6.82%, 5.78%, and 2.74%, respectively. Their diameters were 86.4, 162.30, and 222.28 nm. We tested the release rate of mitoxantrone in phosphate-buffered saline for 48 h: the release rate was 38.73%, 42.35%, and 58.89% for the three CHPs. The hydrophobic substitution degree in the polymer was associated with the self-assembly process of the nanoparticles, which affected their size and therefore drug release rate. The release of the three drug-loaded nanoparticles was significantly accelerated in acid release media. The larger the nanoparticle, the greater the drug release velocity. At 24 h, the IC₅₀ value was 0.25 M, for the best inhibition of mitoxantrone on bladder cancer cells.3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) experiments demonstrated that drug-loaded CHP-3 nanoparticles with the largest size were the most toxic to bladder cancer cells. Immunofluorescence and flow cytometry revealed that drug-loaded CHP-3 nanoparticles with the largest size had the strongest effect on promoting apoptosis of bladder cancer cells. Also, the three drug-loaded nanoparticles could all inhibit the migration of MB49 cells, with large-size CHP-3 nanoparticles having the most powerful inhibition.

Hybrid nanoparticles based on chlorin e6-conjugated hyaluronic acid/poly(l-histidine) copolymer for theranostic application to tumors

The aim of this study is to synthesize multifunctional hybrid nanoparticles composed of hyaluronic acid (HA) and poly(l-histidine) (PHS) with a disulfide linkage and chlorin e6 (HAPHSce6ss) for diagnostic and therapeutic application against breast tumor cells. The reductive end of HA was conjugated with cystamine to make a disulfide linkage (HA-cystamine). PHS was conjugated with Ce6 with the aid of carbodiimide chemistry (PHS-ce6). Then, HA-cystamine was conjugated with the carboxyl group of Ce6 to make an HAPHSce6ss copolymer. Nanoparticles of HAPHSce6ss copolymer have small particle sizes of less than 100 nm and their diameters increased with acidic pH, indicating that HAPHSce6ss nanoparticles have pH-sensitivity. Furthermore, ce6 was activated in the acidic environment and had redox-status in a fluorescence study. In a cell culture study, the nanoparticles were specifically targeted at the CD44 receptor of MDA-MB231 cells while CD44-negative MCF7 cells had no CD44-specificity. The nanoparticles exhibited an enhanced association with cells and were more fluorescent at acidic pH or in the presence of GSH. They inhibited the growth of tumor cells in a CD44 receptor specific or pH-sensitive manner. In an in vivo animal tumor xenograft study using mice, HAPHSce6ss nanoparticles predominantly targeted an MDA-MB231 tumor rather than an MCF7 tumor and effectively inhibited tumor growth. HAPHSce6ss nanoparticles have CD44 specificity, pH/redox dual sensitivity and a fluorescence diagnostic function against tumor cells. We suggest that HAPHSce6ss nanoparticles are a promising candidate for theranostic application to tumors.

Synthesis, Structural Characterization, and Preclinical Efficacy of a Novel Paclitaxel-Loaded Alginate Nanoparticle for Breast Cancer Treatment

Purpose. The antitumor activity of a novel alginate (ALG) polymer-based particle that contained paclitaxel (PTX) was evaluated using human primary breast cancer cells. Materials and Methods. PTX was combined with ALG in a nanoparticle as a drug delivery system designed to improve breast cancer tumor cell killing. PTX-ALG nanoparticles were first synthesized by nanoemulsification polymer cross-linking methods that improved the aqueous solubility. Structural and biophysical properties of the PTX-ALG nanoparticles were then determined by transmission electron microscopy (TEM) and high performance liquid chromatography (HPLC) fluorescence. The effect on cell cycle progression and apoptosis was determined using flow cytometry. Results. PTX-ALG nanoparticles were prepared and characterized by ultraviolet (UV)/visible (VIS), HPLC fluorescence, and TEM. PTX-ALG nanoparticles demonstrated increased hydrophobicity and solubility over PTX alone. Synthetically engineered PTX-ALG nanoparticles promoted cell-cycle arrest, reduced viability, and induced apoptosis in human primary patient breast cancer cells superior to those of PTX alone. Conclusion. Taken together, our results demonstrate that PTX-ALG nanoparticles represent an innovative, nanoscale delivery system for the administration of anticancer agents that may avoid the adverse toxicities with enhanced antitumor effects to improve the treatment of breast cancer patients.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Curcumin loaded on pullulan acetate nanoparticles protects the liver from damage induced by DEN

Curcumin loaded nanoparticles protect liver from damage induced by DEN.

Polysaccharides for the Delivery of Antitumor Drugs

Among the several delivery materials available so far, polysaccharides represent very attractive molecules as they can undergo a wide range of chemical modifications, are biocompatible, biodegradable, and have low immunogenic properties. Thus, polysaccharides can contribute to significantly overcome the limitation in the use of many types of drugs, including anti-cancer drugs. The use of conventional anti-cancer drugs is hampered by their high toxicity, mostly depending on the indiscriminate targeting of both cancer and normal cells. Additionally, for nucleic acid based drugs (NABDs), an emerging class of drugs with potential anti-cancer value, the practical use is problematic. This mostly depends on their fast degradation in biological fluids and the difficulties to cross cell membranes. Thus, for both classes of drugs, the development of optimal delivery materials is crucial. Here we discuss the possibility of using different kinds of polysaccharides, such as chitosan, hyaluronic acid, dextran, and pullulan, as smart drug delivery materials. We first describe the main features of polysaccharides, then a general overview about the aspects ruling drug release mechanisms and the pharmacokinetic are reported. Finally, notable examples of polysaccharide-based delivery of conventional anti-cancer drugs and NABDs are reported. Whereas additional research is required, the promising results obtained so far, fully justify further efforts, both in terms of economic support and investigations in the field of polysaccharides as drug delivery materials.

Novel pullulan bioconjugate for selective breast cancer bone metastases treatment

A novel polysaccharide bioconjugate was designed to selectively target breast cancer bone metastases using a bisphosphonate moiety (alendronate, ALN). Paclitaxel (PTX) was first covalently conjugated to pullulan (Pull) through a Cathepsin K-sensitive tetrapeptide spacer followed by a self-immolative aminobenzyl alcohol spacer to obtain Pull-(GGPNle-φ-PTX). ALN was then conjugated to the polymeric backbone of Pull-(GGPNle-φ-PTX) via a PEG spacer. The final bioconjugate Pull-(GGPNle-φ-PTX)-(PEG-ALN) was found to assemble into colloidal spherical structures, which were physically and chemically stable under physiological conditions. In vitro studies showed that Pull-(GGPNle-φ-PTX)-(PEG-ALN) had strong affinity for hydroxyapatite, which simulates the bone tissue. Paclitaxel was rapidly released from the bioconjugate by Cathepsin K cleavage under pathological conditions. All studies performed using human MDA-MB-231-BM (bone metastases-originated clone), murine 4T1 breast cancer cells, murine K7M2, and human SAOS-2 osteosarcoma cells showed that the bioconjugate exerted an enhanced antiproliferative activity compared to the conjugate without the ALN. Furthermore, the nanoconjugate inhibited the migration of cancer cells and further displayed potent anti-angiogenic activity. In conclusion, the results showed that this conjugate has an excellent potential for selective treatment of bone neoplasms such as breast cancer bone metastases and osteosarcoma.

New shell crosslinked micelles from dextran with hydrophobic end groups and their interaction with bioactive molecules

Micelles formed in aqueous solution by dextran with hydrophobic (alkyl) end-groups were stabilized through divinyl sulfone crosslinking of the dextran shell. The efficacy of the crosslinking reaction was influenced by the divinyl sulfone amount, the pH and micelle concentration. Crosslinked micelles with a moderate crosslinking degree were further functionalized by attachment of 10 and 17 moles% N-(2-hydroxypropyl)-N,N-dimethyl-N-benzylammonium chloride groups along the dextran chain. The size and shape of both crosslinked micelles and their cationic derivatives were analyzed by DLS and TEM. The prepared micelles were able to bind anionic diclofenac (60-370 mg/g), hydrophobic anionic indometacin (70-120 mg/g), and hydrophobic alpha-tocopherol (170-220 mg/g) or ergocalciferol (90-110 mg/g) by hydrophobic or/and electrostatic forces. The release experiments and the antioxidant activity of bound alpha-tocopherol highlighted the potential of the new nano-sized micelles mainly as carriers for prolonged and controlled delivery of hydrophobic drugs.

Self-assembled polymeric micelles based on hyaluronic acid-g-poly(D,L-lactide-co-glycolide) copolymer for tumor targeting

Graft copolymer composed hyaluronic acid (HA) and poly(d,l-lactide-co-glycolide) (PLGA) (HAgLG) was synthesized for antitumor targeting via CD44 receptor of tumor cells. The carboxylic end of PLGA was conjugated with hexamethylenediamine (HMDA) to have amine end group in the end of chain (PLGA-amine). PLGA-amine was coupled with carboxylic acid of HA. Self-assembled polymeric micelles of HAgLG have spherical morphologies and their sizes were around 50–200 nm. Doxorubicin (DOX)-incorporated polymeric micelles were prepared by dialysis procedure. DOX was released over 4 days and its release rate was accelerated by the tumoric enzyme hyaluronidase. To assess targetability of polymeric micelles, CD44-positive HepG2 cells were employed treated with fluorescein isothiocyanate (FITC)-labeled polymeric micelles. HepG2 cells strongly expressed green fluorescence at the cell membrane and cytosol. However, internalization of polymeric micelles were significantly decreased when free HA was pretreated to block the CD44 receptor. Furthermore, the CD44-specific anticancer activity of HAgLG polymeric micelles was confirmed using CD44-negative CT26 cells and CD44-positive HepG2 cells. These results indicated that polymeric micelles of HaLG polymeric micelles have targetability against CD44 receptor of tumor cells. We suggest HAgLG polymeric micelles as a promising candidate for specific drug targeting.

Antiproliferative effect of benzimidazole anthelmintics albendazole, ricobendazole, and flubendazole in intestinal cancer cell lines

This study aimed to test the antiproliferative effect of three benzimidazole anthelmintics in intestinal cancer cells and to investigate whether these drugs, which inhibit tubulin polymerization, can potentiate the efficacy of the microtubule-stabilizing drug paclitaxel (PTX). Four intestinal cancer cell lines, SW480, SW620, HCT8, and Caco2, with different origins and growth characteristics were used. The antiproliferative effect of albendazole (ABZ), ricobendazole (RBZ), flubendazole (FLU), and their combinations with PTX was tested using three different end-point viability assays, cell cycle distribution analysis, and the x-CELLigence System for real-time cell analysis. ABZ and FLU inhibited cell proliferation significantly in a concentration-dependent and time-dependent manner through cell arrest in the G2/M phase. RBZ was not effective at any concentration tested. The cell lines differed in sensitivity to FLU and ABZ, with HCT8 being the most sensitive, showing IC₅₀ values for ABZ and FLU that reached 0.3 and 0.9 μmol/l, respectively. Combinations of PTX+ABZ and PTX+FLU decreased cell viability more effectively when compared with treatment with individual drugs alone. The anthelmintic benzimidazole drugs ABZ and FLU show a significant cytostatic effect and potentiate the efficacy of PTX in intestinal cancer cells.

Paclitaxel isomerisation in polymeric micelles based on hydrophobized hyaluronic acid

Physical and chemical structure of paclitaxel (PTX) was studied after its incorporation into polymeric micelles made of hyaluronic acid (HA) (Mw=15 kDa) grafted with C6 or C18:1 acyl chains. PTX was physically incorporated into the micellar core by solvent evaporation technique. Maximum loading capacity for HAC6 and HAC18:1 was determined to be 2 and 14 wt.%, respectively. The loading efficiency was higher for HAC18:1 and reached 70%. Independently of the derivative, loaded HA micelles had spherical size of approximately 60-80 nm and demonstrated slow and sustained release of PTX in vitro. PTX largely changed its form from crystalline to amorphous after its incorporation into the micelle's interior. This transformation increased PTX sensitivity towards stressing conditions, mainly to UV light exposure, during which the structure of amorphous PTX isomerized and formed C3C11 bond within its structure. In vitro cytotoxicity assay revealed that polymeric micelles loaded with PTX isomer had higher cytotoxic effect to normal human dermal fibroblasts (NHDF) and human colon carcinoma cells (HCT-116) than the same micelles loaded with non-isomerized PTX. Further observation indicated that PTX isomer influenced in different ways cell morphology and markers of cell cycle. Taken together, PTX isomer loaded in nanocarrier systems may have improved anticancer activity in vivo than pure PTX.

Pullulan-based nanoparticles as carriers for transmucosal protein delivery

Polymeric nanoparticles have revealed very effective in transmucosal delivery of proteins. Polysaccharides are among the most used materials for the production of these carriers, owing to their structural flexibility and propensity to evidence biocompatibility and biodegradability. In parallel, there is a preference for the use of mild methods for their production, in order to prevent protein degradation, ensure lower costs and easier procedures that enable scaling up. In this work we propose the production of pullulan-based nanoparticles by a mild method of polyelectrolyte complexation. As pullulan is a neutral polysaccharide, sulfated and aminated derivatives of the polymer were synthesized to provide pullulan with a charge. These derivatives were then complexed with chitosan and carrageenan, respectively, to produce the nanocarriers. Positively charged nanoparticles of 180-270 nm were obtained, evidencing ability to associate bovine serum albumin, which was selected as model protein. In PBS pH 7.4, pullulan-based nanoparticles were found to have a burst release of 30% of the protein, which maintained up to 24h. Nanoparticle size and zeta potential were preserved upon freeze-drying in the presence of appropriate cryoprotectants. A factorial design was approached to assess the cytotoxicity of raw materials and nanoparticles by the metabolic test MTT. Nanoparticles demonstrated to not cause overt toxicity in a respiratory cell model (Calu-3). Pullulan has, thus, demonstrated to hold potential for the production of nanoparticles with an application in protein delivery.

Biopolymer-based nanoparticles for drug/gene delivery and tissue engineering

There has been a great interest in application of nanoparticles as biomaterials for delivery of therapeutic molecules such as drugs and genes, and for tissue engineering. In particular, biopolymers are suitable materials as nanoparticles for clinical application due to their versatile traits, including biocompatibility, biodegradability and low immunogenicity. Biopolymers are polymers that are produced from living organisms, which are classified in three groups: polysaccharides, proteins and nucleic acids. It is important to control particle size, charge, morphology of surface and release rate of loaded molecules to use biopolymer-based nanoparticles as drug/gene delivery carriers. To obtain a nano-carrier for therapeutic purposes, a variety of materials and preparation process has been attempted. This review focuses on fabrication of biocompatible nanoparticles consisting of biopolymers such as protein (silk, collagen, gelatin, β-casein, zein and albumin), protein-mimicked polypeptides and polysaccharides (chitosan, alginate, pullulan, starch and heparin). The effects of the nature of the materials and the fabrication process on the characteristics of the nanoparticles are described. In addition, their application as delivery carriers of therapeutic drugs and genes and biomaterials for tissue engineering are also reviewed.