Bovine Serum Albumin Shell Research Articles

The fabrication of protein microbubbles with diverse gas core and the novel exploration on the role of interface introduction in protein crystallization

Recently, microbubbles with diameters ranging from a few to tens of microns have an increasing attractive attention in various applications. For microbubbles, exploring convenient and reliable fabrication approach is crucial, in particular achieving stable microbubbles filled with diverse gas. In this work, the baffled high intensity agitation (BHIA) cell was utilized to generate bovine serum albumin (BSA)-coated microbubbles. The characteristics of generated air-filled microbubbles was explored by adjustment of operating parameters. It was found that the microbubble size mainly depends on employed agitation speed. Microbubbles filled with different gas, such as N2, O2, and CO2, also were successfully obtained and show good stability at room temperature due to the formation of thick and elastic BSA shell. It was interestingly observed that a large number of regular BSA particles scattered around the trajectory of microbubble interfaces by scanning electron microscopy, which was obviously different from the particles formed from BSA solution in absence of microbubbles. The mechanism behind the phenomenon was investigated, and it was found that the abundant gas-liquid interface introduced by microbubbles is responsible for triggering the oriented aggregation of BSA molecules. The founding may reveal a spur significant for the effect of gas-liquid interface on the formation of protein crystals.

PH Sensitive Peptide Functionalized High Stability Polymeric Nanoparticles for Mitochondria Targeted Cancer Drug Delivery

A major focus of cancer nanomedicine is to achieve a high therapeutic index for cancer therapy. Despite the unprecedented growth in the development of polymeric self-assembled nanosystems, only a few of them end up in clinics (e.g. Doxil) as a result of (i) poor stability, (ii) drug leakage and (iii) dissociation kinetics due to the strong influence of blood components in vivo. The most common method for improving nanocarrier stability is to tune the drug hydrophobicity and polymer matrix miscibility under complex chemical reaction conditions, that leads to poor drug cytotoxicity and attenuation of therapeutic efficacy. To address these challenges, we have designed a simple and robust poly (lactide-co-glycolide) (PLGA) and bovine serum albumin (BSA) hybrid nanoparticles to provide high stability and trigger drug release inside cancer cells. The hybrid nanoparticles were prepared by covalently wrapping BSA over the surface of drug-loaded PLGA nanoparticles using simple carbodiimide-chemistry in mild reaction conditions. To increase the stability, the BSA shells were crosslinked. The BSA shells can be dissociated in the high redox microenvironment of the tumor and within the cancer cells. Subsequently, the drugs loaded into the PLGA core can be released by accelerated degradation (hydrolysis) due to the low pH conditions in the tumor microenvironment and lysosomal compartments. The cancer cell targeting ability of the hybrid NPs was achieved by coupling of the amino groups of the BSA shell with a pH-sensitive peptide (acidity-triggered rational membrane peptide, ATRAM). The insertion of the ATRAM-BSA-PLGA nanoparticles into cancer cell membranes occurs at the peritumoral pH (6.5). In vitro studies showed highly-efficient pH-dependent uptake and remarkable cytotoxicity of doxorubicin triphenylphosphine loaded ATRAM-BSA-PLGA NPs. Our results demonstrate that the novel pH-sensitive peptide-functionalized high stability BSA-PLGA nanoparticles are a highly promising nanoplatforms.

AS1411 Aptamer Conjugated Gold Nanoclusters as a Targeted Radiosensitizer for Megavoltage Radiation Therapy of 4T1 Breast Cancer Cells

Introduction: In the present study, AS1411 aptamer conjugated gold nanoclusters (GNCs) have been introduced as a targeted radiosensitizer for enhancing megavoltage radiation therapy efficacy. RT has identified as an effective therapeutic modality for many different types of solid tumors. However, equal radiation beams absorption by tumor and surrounding healthy tissues is still a great challenge in RT which is caused by attenuation coefficient factor similarity. In order to overcome this challenge and to increase the efficacy of radiation therapy, radiosensitizers has been recommended. Materials and Methods: GNCs with ultra-small gold core and bovine serum albumin shell (BSA) as a versatile Nano-platform were synthesized and conjugated to AS1411 aptamer (Apt-GNCs). Due to nucleolin overexpression in breast cancer cells and high affinity of the AS1411 aptamer to nucleolin, mouse mammary carcinoma cell line (4T1) was selected as malignant cells and murine fibroblast (L929) was used as a normal cell line. Results: Flow cytometry assessments reveal a significant increase of GNCs uptake by the cancer cells in the presence of the aptamer as the targeting agent. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements demonstrate 4 times more Apt-GNCs uptake by 4T1 cells than the normal cells at concentration ratio of 1:40 (4µM Aptamer and 160 µM GNCs at 24h incubation). Conclusion: Combination of megavoltage radiation therapy and Apt-GNCs as radiosensitizer causes effective cancer cells killing and obtaining dose enhancement factor (DEF) about 2.7 in clonogenic survival assay.

Dual Activity of Rose Bengal Functionalized to Albumin-Coated Lanthanide-Doped Upconverting Nanoparticles: Targeting and Photodynamic Therapy.

A modified version of a desolvation method was used to render lanthanide-doped upconverting nanoparticles NaGdF4:Yb3+/Er3+ (Ln-UCNPs) water-dispersible and biocompatible for photodynamic therapy. Bovine serum albumin (BSA) was used as surface coating with a direct conjugation to NaGdF4:Yb3+/Er3+ nanoparticles forming a ∼2 nm thick shell. It was estimated that approximately 112 molecules of BSA were present and cross-linked per NaGdF4:Yb3+/Er3+ nanoparticle. Analysis of the BSA structural behavior on the Ln-UCNP surfaces displayed up to 80% loss of α-helical content. Modification of the Ln-UCNPs with a BSA shell prevents luminescence quenching from solvent molecules (H2O) with high energy vibrations that can interact with the excited states of the optically active ions Er3+ and Yb3+ via dipole-dipole interactions. Additionally, the photosensitizer rose bengal (RB) was conjugated to albumin on the surface of the Ln-UCNPs. Emission spectroscopy under 980 nm excitation was carried out, and an energy transfer efficiency of 63% was obtained. In vitro cell studies performed using human lung cancer cells (A549 cell line) showed that Ln-UCNPs coated with BSA were not taken by the cells. However, when RB was conjugated to BSA on the surface of the nanoparticles, cellular uptake was observed, and cytotoxicity was induced by the production of singlet oxygen under 980 nm irradiation.

Core–shell–corona doxorubicin-loaded superparamagnetic Fe3O4 nanoparticles for cancer theranostics

Superparamagnetic iron oxide magnetic nanoparticles (MNPs) are successfully used as contrast agents in magnetic-resonance imaging. They can be easily functionalized for drug delivery functions, demonstrating great potential for both imaging and therapeutic applications. Here we developed new pH-responsive theranostic core–shell–corona nanoparticles consisting of superparamagentic Fe3O4 core that displays high T2 relaxivity, bovine serum albumin (BSA) shell that binds anticancer drug, doxorubicin (Dox) and poly(ethylene glycol) (PEG) corona that increases stability and biocompatibility. The nanoparticles were produced by adsorption of the BSA shell onto the Fe3O4 core followed by crosslinking of the protein layer and subsequent grafting of the PEG corona using monoamino-terminated PEG via carbodiimide chemistry. The hydrodynamic diameter, zeta-potential, composition and T2 relaxivity of the resulting nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, thermogravimetric analysis and T2-relaxometry. Nanoparticles were shown to absorb Dox molecules, possibly through a combination of electrostatic and hydrophobic interactions. The loading capacity (LC) of the nanoparticles was 8wt.%. The Dox loaded nanoparticles release the drug at a higher rate at pH 5.5 compared to pH 7.4 and display similar cytotoxicity against C6 and HEK293 cells as the free Dox.

Facile Construction of Near Infrared Fluorescence Nanoprobe with Amphiphilic Protein-Polymer Bioconjugate for Targeted Cell Imaging.

A simple, straightforward, and reproducible strategy for the construction of a near-infrared (NIR) fluorescence nanoprobe was developed by coating CuInS2/ZnS quantum dots (CIS/ZnS QDs) with a novel amphiphilic bioconjugate. The amphiphilic bioconjugate with a tailor-designed structure of bovine serum albumin (BSA) as the hydrophilic segment and poly(ε-caprolactone) (PCL) as the hydrophobic part was fabricated by chemical coupling the hydrophobic polymer chain to BSA via the maleimide-sulfhydryl reaction. By incorporating CIS/ZnS QDs into the hydrophobic cores of the self-assembly of BSA-PCL conjugate, the constructed NIR fluorescence nanoprobe exhibited excellent fluorescent properties over a wide pH range (pH 3-10) and a good colloidal stability in PBS buffer (pH = 7.4) with or without 10% fetal bovine serum. The presence of the outer BSA shell effectively reduced the nonspecific cellular binding and imparted high biocompatibility and low-toxicity to the probe. Moreover, the NIR fluorescence nanoprobe could be functionalized by conjugating cyclic Arg-Gly-Asp (cRGD) peptide, and the decorated nanoprobe was shown to be highly selective for targeted integrin αvβ3-overexpressed tumor cell imaging. The feasibility of the constructed NIR fluorescence probe in vivo application was further investigated and the results demonstrated its great potential for in vivo imaging. This developed protocol for phase transfer of the CIS/ZnS QDs was universal and applicable to other nanoparticles stabilized with hydrophobic ligands.

Capacitance Measurement of SiO2@BSA Core–Shell Nanoparticles Using AC Impedance Spectroscopy

Electrical properties of core–shell nanoparticles with protein shell layers have not been fully surveyed, although such nanoparticles have been studied widely as model biomimetic particles. In this study, we demonstrated that the capacitance changes of a silica (SiO2)/bovine serum albumin (BSA) core–shell nanoparticle (SiO2@BSA) could be monitored with variation of BSA shell thickness using AC impedance spectroscopy combined with conductive atomic force microscopy (c-AFM). Impedance spectra showed that the resistance and capacitance of SiO2@BSA core–shell nanoparticles increased with increasing BSA shell thickness. Within the range of experimental conditions studied, the capacitance of SiO2@BSA increased linearly with increasing number of BSA layers, corresponding to a 5.4 pF rise per single layer of BSA after the first two layer deposition of BSA. This result demonstrated that the minute changes of the electrical properties that were induced by the shell protein layer can be monitored and quantified using impedance spectroscopy.

Synthesis and Peroxidase‐Like Activity of Salt‐Resistant Platinum Nanoparticles by Using Bovine Serum Albumin as the Scaffold

AbstractA green approach is proposed for the synthesis of Pt nanoparticles (PtNPs) in the bovine serum albumin (BSA) scaffold through biomineralization. The resulting BSA–PtNPs have been proved to function as peroxidase mimics that can catalyze the reaction of various peroxidase substrates in the presence of H2O2. Kinetic studies indicate that BSA–PtNPs have a much higher affinity for H2O2 than the NPs of other Pt‐based peroxidase mimics. Furthermore, the BSA shell plays an important role in promoting the robust stability of PtNPs. Even in high ionic strength environment (2 M NaCl), the catalytic activity can be well preserved. These excellent properties make the BSA–PtNPs an ideal candidate for a wide range of potential applications as peroxidase mimics.

Molecular-receptor-specific, non-toxic, near-infrared-emitting Au cluster-proteinnanoconjugates for targeted cancer imaging

Molecular-receptor-targeted imaging of folate receptor positiveoral carcinoma cells using folic-acid-conjugated fluorescentAu25 nanoclusters (Au NCs) is reported. Highly fluorescentAu25 clusters were synthesized by controlled reduction ofAu+ ions, stabilized in bovine serum albumin (BSA), using a green-chemical reducingagent, ascorbic acid (vitamin-C). For targeted-imaging-based detection ofcancer cells, the clusters were conjugated with folic acid (FA) throughamide linkage with the BSA shell. The bioconjugated clusters show excellentstability over a wide range of pH from 4 to 14 and fluorescence efficiency of∼5.7% at pH 7.4 in phosphate buffer saline (PBS), indicating effective protection of nanoclusters byserum albumin during the bioconjugation reaction and cell–cluster interaction. The nanoclusterswere characterized for their physico-chemical properties, toxicity and cancer targeting efficacyin vitro. X-ray photoelectron spectroscopy (XPS) suggests binding energies correlating to metalAu 4f7/2∼83.97 eVand Au 4f5/2∼87.768 eV. Transmission electron microscopy and atomic force microscopyrevealed the formation of individual nanoclusters of size∼1 nm and protein clusteraggregates of size ∼8 nm. Photoluminescence studies show bright fluorescence with peak maximum at∼674 nm with the spectral profile covering the near-infrared (NIR) region, making it possible toimage clusters at the 700–800 nm emission window where the tissue absorption oflight is minimum. The cell viability and reactive oxygen toxicity studies indicatethe non-toxic nature of the Au clusters up to relatively higher concentrations of500 µg ml−1. Receptor-targeted cancer detection using Au clusters is demonstrated onFR+ve oralsquamous cell carcinoma (KB) and breast adenocarcinoma cell MCF-7, where the FA-conjugatedAu25 clusters were found internalized in significantly higher concentrations compared to thenegative control cell lines. This study demonstrates the potential of using non-toxicfluorescent Au nanoclusters for the targeted imaging of cancer.