Cationized bovine serum albumin as gene carrier: Influence of specific secondary structure on DNA complexibility and gene transfection

Bacteria-driven hypoxia targeting delivery of chemotherapeutic drug proving outcome of breast cancer

Local hypoxia is a common feature of many solid tumors and may lead to unsatisfactory chemotherapy outcomes. Anaerobic bacteria that have an affinity to hypoxic areas can be used to achieve targeted drug delivery in tumor tissues. In this study, we developed a biocompatible bacteria/nanoparticles biohybrid (Bif@DOX-NPs) platform that employs the anaerobic Bifidobacterium infantis (Bif) to deliver adriamycin-loaded bovine serum albumin nanoparticles (DOX-NPs) into breast tumors. The Bif@DOX-NPs retained the targeting ability of B. infantis to hypoxic regions, as well as the cytotoxicity of DOX. The biohybrids were able to actively colonize the hypoxic tumors and significantly increased drug accumulation at the tumor site. The DOX concentration in the tumor masses colonized by Bif@DOX-NPs was 4 times higher than that in the free DOX-treated tumors, which significantly prolonged the median survival of the tumor-bearing mice to 69 days and reduced the toxic side-effects of DOX. Thus, anaerobic bacteria-based biohybrids are a highly promising tool for the targeted treatment of solid tumors with inaccessible hypoxic regions.

Microencapsulation of functional ovalbumin and bovine serum albumin with polylysine-alginate complex for sustained protein vehicle's development

Overcoming harsh gastric environment is still a challenging to bioactive proteins, microencapsulation provides one strategy in designing this protection barrier. In this work, bovine serum albumin and ovalbumin were chosen as model proteins, while polylysine-alginate complex was fabricated for microencapsulation purpose. Both of the protein-loaded microcapsules had regular internal microstructures. The model protein's embedding increased the thermal stability of the microcapsules. Both of the protein-loaded microcapsules had a slow release rate in simulated gastric fluids (pH 3.0), while a sustained release profile in simulated intestinal fluids (pH 6.4), indicating an excellent tolerance to the acidic gastric environment. The microencapsulation process was mild and had no influence on the protein's molecular weight, while a slight peak shifting occurred in the secondary structure of the released proteins. The developed microcapsules could be explored as a kind of vehicle for bioactive proteins applied in functional foods, health care products and medical formulations.

Infrared Absorption Spectroscopy of Albumin Binding with Amine-Containing Plasma Polymer Coatings on Nanoporous Diamond Surfaces

Nanocrystalline diamond (NCD) layers functionalized with amine-containing functional groups have generated considerable interest as biocompatible substrates for attachment of biomolecules and cells with a view to biosensor and tissue engineering applications. Here we prepare nanoporous diamond layers with the surfaces modified by hydrogen plasma, oxygen plasma, and conformal 7 nm amine-containing plasma polymer (PP). Immobilization of bovine serum albumin (BSA) molecules is characterized on such surfaces. Grazing angle reflectance infrared spectroscopy as well as X-ray photoelectron spectroscopy show that concentration of amine-containing bonds after BSA exposure depends on the type of NCD surface modification. AFM measurements reveal that BSA proteins are physisorbed on H- and O-terminated diamond surfaces in different thicknesses and morphology. When the diamond layers are coated with the amine-containing PP, BSA molecules assume similar thickness and morphology, and their adhesion is significantly increased on both types of the diamond surfaces.

Performance Evaluation of Miniature Integrated Electrochemical Cells Fabricated Using LTCC Technology

Miniaturized and integrated analytical devices, including chemical sensors, are at the forefront of modern analytical chemistry. The construction of novel analytical tools takes advantage of contemporary micro- and nanotechnologies, as well as materials science and technology. Two electrochemical techniques were used in experiments: electrochemical impedance spectroscopy and cyclic voltammetry. The goal of this study was to investigate electron transfer resistance in a model solution containing Fe2+/3+ ions and protein adsorption using integrated electrochemical cells with different geometry. Tests performed at various Fe2+/3+ concentration allowed to verify that these cells work properly. The influence of bovine serum albumin adsorbing to the surface of the integrated electrochemical cells was investigated. In electrochemical impedance spectroscopy, the value of Rct increased with protein adsorption and the relative change of Rct was in range 21% to 55%. In cyclic voltammetry the decreasing amperometric response of the working electrode was used as evidence of protein adsorption on the electrode.

Worm-Like Biomimetic Nanoerythrocyte Carrying siRNA for Melanoma Gene Therapy

A major challenge in siRNA vectors is developing approaches that ensure that when administered in vivo, the vectors can target their requisite site of action. This study reports a third type of nanoworm, biomimetic nanoerythrocytes for siRNA delivery, except for filomicelle and nanoworm iron-oxide particle, which is the first approach that allows for targeted siRNA delivery by a process involving red blood cell (RBC) membrane cloaking of charge-reversible polyplexes of siRNA and polycation. RBC membrane cloaking protects siRNA from RNase A degradation. Moreover, the RBC membrane-cloaked charge-reversible siRNA vector (RBC-reversible polyplex (RP)) not only stays longer in the blood circulation than that of negatively charged bovine serum albumin (BSA) spheres and positively charged BSA, but is also able to escape from late endosomes/lysosomes, to achieve effective transfection for gene knockdown. The knockdown result in vivo is remarkably consistent with that of intracellular trafficking and transfection in vitro. Due to the outstanding biocompatibility and active targeting (cRGD), the 7 mg kg^-1 dose siSurvivin in RGD-RBC-RP exhibits obviously superior anticancer effects at the animal level after two weeks. Therefore, the biomimetic worm-like nanoerythrocyte charge-reversible gene vector is a new and general method for highly efficient siRNA therapy in vivo.

Protein moiety in oligochitosan modified vector regulates internalization mechanism and gene delivery: Polyplex characterization, intracellular trafficking and transfection

Oligochitosan-modified proteins have gained attention as efficient non-viral vectors for gene delivery. However, little information exists if protein moieties can serve as an important role for internalization and endosome escape ability of the genetic material. To explore this issue, we designed two cationic oligochitosan-modified vectors that consist of different proteins, namely a hydrophobic plant protein (zein) and a hydrophilic animal protein (ovalbumin (OVA)) to deliver pDNA to epithelial cell line CHO-K1 and HEK 293 T. These cationic vectors were systematically characterized by molecular weight, infrared (IR) structural analysis, transmission electron microscopy (TEM) morphology, and surface charge. A remarkable impact of protein moieties was observed on physiochemical properties of the developed vectors. Oligochitosan-modified zein containing hydrophobic protein exhibited high buffering capacity and excellent DNA binding ability compared to the oligochitosan-modified OVA. The data on transfection in the presence of endocytic inhibitors indicated that the caveolae-mediated pathway (CvME) played a key role in the internalization of the zein-based polyplex. However, the OVA-based polyplex was internalized in CHO-K1 cells via CvME and in HEK 293 T cells via the lipid-mediated pathway. Moreover, oligochitosan-modified zein exhibited lower cytotoxicity, greater lysosomal escape ability, better plasmid stability, and better transfection efficiency than the oligochitosan-modified OVA. This study offers a facile procedure for the synthesis of cationic vectors and elucidates the relationship that exists between protein moieties and transfection activity, thus providing an alternative, non-viral platform for the gene delivery.

Synthesis and characterization of small-sized gold nanoparticles coated by bovine serum albumin (BSA) for cancer photothermal therapy

In the present study, small gold nanoparticles <5 nm coated with natural protein Bovine Serum Albumin (BSA) was synthesized and characterized using UV-vis spectrophotometer, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta potential and scanning electron microscopy (SEM). Three types of cancer cell lines; Rhabdomyosarcoma (RD), Murine fibroblast (L20B) and RAW 264.7 monocyte-macrophage (MQ) were tested and treated by photothermal strategy, in vitro, by conjugating BSA-AuNPs complex of (0.125, 0.25, 0.5 and 1 mg/ml) concentrations with continuous low power laser irradiation, green (532 nm) and near-infrared (NIR) (800 nm) at 0.5, 1, 2 and 3 min, separately. Cytotoxicity effect was determined by MTT assay. The vital impact of photothermal technique has investigated at 1 mg/ml and 3 min irradiation period as identified in RD cell line in comparison with other types; where cytotoxicity more than 74% was reached. Prominent results were demonstrated in the green and NIR region by pH -induced aggregation effect of small nanoparticles inside the cancer cells, which make the small-sized BSA-AuNPs are promising agents for cancer photothermal therapy.

DNA-loaded microbubbles with crosslinked bovine serum albumin shells for ultrasound-promoted gene delivery and transfection

The microbubble is a kind of clinically applied ultrasound contrast agent in disease diagnosis that can also rupture under sonication to increase membrane permeability and promote gene entry into targeted cells. However, the development of ultrasound-mediated gene delivery might be restricted because genes and microbubbles were separated and would not reach the targeted cells simultaneously. Herein, a kind of crosslinked positive microbubbles (CPMBs) were prepared to load DNA as gene vectors to promote gene delivery efficiency. The BSA shell of the CPMBs was crosslinked with disulfide bonds, which obviously enhanced the stability of the CPMBs. Furthermore, the CPMBs revealed sonoporation effects comparable to those of clinically applied SonoVue microbubbles. As DNA and CPMBs were electrostatically linked as an entirety, they would reach cells simultaneously. Thus, with the aid of ultrasound, these DNA-loaded microbubbles promoted DNA entry into cytoplasm more effectively and obtained higher cellular uptake efficiency and better transfection efficiency than DNA-mixed microbubbles. Confocal microscopy results showed that rupturing of the CPMBs/DNA entire microbubbles under sonication could carry DNA directly into the cytoplasm or nucleus. All results indicated that the cytocompatible DNA-loaded microbubbles have promising prospects in ultrasound-mediated gene delivery.

An easy gene assembling strategy for light-promoted transfection by combining host-guest interaction of cucurbit[7]uril and gold nanoparticles

Cucurbit[7]uril (CB[7]), a representative member of the host family cucurbit[n]uril, can host-guest interact with many guest molecules such as adamantane, viologen and naphthalene derivatives. This host-guest interaction provides an easy strategy in gene vector assembling. Furthermore, CB[7] can self-assemble on gold nanospheres (AuNSs). Herein, the combination of CB[7] and AuNSs provides both advantages of host-guest interaction and photo-thermal effect of AuNSs. In this study, polyethyleneimine (PEI) and polyethylene glycol (PEG) were separately interacted with CB[7] via host-guest interaction. Then by assembling on AuNSs, PEI and PEG were combined together to condense DNA into polyplexes as well as enhance circulation stability of the polyplexes. These gene vectors were found to have high cellular uptake efficiency and low cytotoxicity. Furthermore, the well distributed AuNSs in the polyplexes could transform light into heat under light exposure because of the photo-thermal effect. This was found to effectively promote the entry of gene into cytoplasm and highly enhanced gene transfection efficiency.