Bovine serum albumin (BSA) and cleaved-BSA conjugated ultrasmall Gd2O3 nanoparticles: Synthesis, characterization, and application to MRI contrast agents

Signal Amplification Pretargeted PET/Fluorescence Imaging Based on Human Serum Albumin-Encapsulated GdF3 Nanoparticles for Diagnosis of Ovarian Cancer

Different modal imaging techniques could be complementary in tumor diagnosis. Human serum albumin (HSA)-encapsulated GdF₃ nanoparticles were developed as T1 magnetic resonance imaging (MRI) contrast agents. However, no significant T1 enhancement in the tumor site of the SKOV3 human ovarian cancer xenograft tumor model was observed within 3 h after injection of tetrazine-modified GdF₃@HSA NPs through small-animal MRI. After intravenous injection of ¹⁸F (or Cy7)-labeled Reppe anhydride, pretargeted positron emission tomography (PET) (near-infrared (NIR) fluorescence) imaging was used to reveal the pharmacokinetics of GdF₃@HSA NPs in the SKOV3 xenograft mouse model to locate the tumor. The probe based on Reppe anhydride achieved rapid ligation with tetrazine-modified GdF₃@HSA nanoparticles (NPs), which accumulated in tumor through Reppe anhydride/tetrazine bioorthogonal chemistry. This pretargeting strategy enabled excellent tumor visualization and quantification at an early period after nanoparticle injection (3 h p.i.), while the MRI images with significant T1 enhancement could be obtained until 24 h after injection of Gd-based contrast agents only. In vivo pretargeted multimodal imaging based on the tetrazine/Reppe anhydride system using HSA-encapsulated GdF₃ nanoparticles would be beneficial for amplification of the imaging signal in the disease site and enhancing diagnostic efficiency.

Safe magnetic resonance imaging on biocompatible nanoformulations

Magnetic resonance imaging (MRI) holds promise for the early clinical diagnosis of various diseases, but most clinical MR techniques require the use of a contrast medium. Several nanomaterial (NM) mediated contrast agents (CAs) are widely used as T1- and T2-based MR contrast agents for clinical and non-clinical applications. Unfortunately, most NM-based CAs are toxic or non-biocompatible, restricting their practical/clinical applications. Therefore, the development of nontoxic and biocompatible CAs for clinical MRI diagnosis is highly desired. To this end, several biocompatible and biomimetic strategies have been developed to offer long blood circulation time, significant biocompatibility, in vivo biodistribution and high contrast ability for efficient imaging. However, detailed review reports on biocompatible NMs, specifically for MR imaging have not yet been summarized. Thus, in the present review we summarize  various surface coating strategies (such as polymers, proteins, cell membranes, etc.) to achieve biocompatible NPs, providing a detailed discussion of advances and future prospects for safe MRI imaging.

Recent Advances in Gadolinium Based Contrast Agents for Bioimaging Applications

Gadolinium (Gd) based contrast agents (CAs) (Gd-CAs) represent one of the most advanced developments in the application of Gd for magnetic resonance imaging (MRI). Current challenges with existing CAs generated an urgent requirement to develop multimodal CAs with good biocompatibility, low toxicity, and prolonged circulation time. This review discussed the Gd-CAs used in bioimaging applications, addressing their advantages and limitations. Future research is required to establish the safety, efficacy and theragnostic capabilities of Gd-CAs. Nevertheless, these Gd-CAs offer extraordinary potential as imaging CAs and promise to benefit bioimaging applications significantly.

The Renal Clearable Magnetic Resonance Imaging Contrast Agents: State of the Art and Recent Advances

The advancements of magnetic resonance imaging contrast agents (MRCAs) are continuously driven by the critical needs for early detection and diagnosis of diseases, especially for cancer, because MRCAs improve diagnostic accuracy significantly. Although hydrophilic gadolinium (III) (Gd3+) complex-based MRCAs have achieved great success in clinical practice, the Gd3+-complexes have several inherent drawbacks including Gd3+ leakage and short blood circulation time, resulting in the potential long-term toxicity and narrow imaging time window, respectively. Nanotechnology offers the possibility for the development of nontoxic MRCAs with an enhanced sensitivity and advanced functionalities, such as magnetic resonance imaging (MRI)-guided synergistic therapy. Herein, we provide an overview of recent successes in the development of renal clearable MRCAs, especially nanodots (NDs, also known as ultrasmall nanoparticles (NPs)) by unique advantages such as high relaxivity, long blood circulation time, good biosafety, and multiple functionalities. It is hoped that this review can provide relatively comprehensive information on the construction of novel MRCAs with promising clinical translation.

Is GSH Chelated Pt Molecule Inactive in Anti-Cancer Treatment? A Case Study of Pt6 GS4

Platinum (Pt) drugs are widely used in anti-cancer treatment although many reports advocated that tumor cells could inactivate Pt drugs via glutathione-Pt (GSH-Pt) adducts formation. To date, GSH chelated Pt molecules have not been assessed in cancer treatment because GSH-Pt adducts are not capable of killing cancer cells, which is widely accepted and well followed. In this report, endogenous biothiol is utilized to precisely synthesize a GSH chelated Pt molecule (Pt₆ GS₄ ). This Pt₆ GS₄ molecule can be well taken up by aggressive triple negative breast cancer (TNBC) cells. Subsequently, its metabolites could enter nuclei to interact with DNA, finally the DNA-Pt complex triggers TNBC cell apoptosis via the p53 pathway. Impressively, high efficacy for anti-cancer treatment is achieved by Pt₆ GS₄ both in vitro and in vivo when compared with traditional first-line carboplatin in the same dosage. Compared with carboplatin, Pt₆ GS₄ keeps tumor bearing mice alive for a longer time and is non-toxic for the liver and kidneys. This work opens a route to explore polynuclear Pt compound with accurate architecture for enhancing therapeutic effects and reducing systemic toxicity.

HSA functionalized Gd2O3:Eu3+ nanoparticles as an MRI contrast agent and a potential luminescent probe for Fe3+, Cr3+, and Cu2+ detection in water

PVP capped Gd₂O₃:Eu³⁺ (PVP@Gd₂O₃:Eu³⁺) and HSA functionalised PVP@Gd₂O₃:Eu³⁺ (HSA@PVP@Gd₂O₃:Eu³⁺) NPs as fluorescent detection probe for metal ion detection and MRI contrast agent.

GdVO4:Eu3+,Bi3+ Nanoparticles as a Contrast Agent for MRI and Luminescence Bioimaging

With the development of multifunctional imaging, gadolinium (Gd)-bearing inorganic nanoparticles (NPs), which were doped with trivalent lanthanide (Ln3+), have been applied in magnetic resonance imaging (MRI) and optical imaging owing to their high payload of Gd3+ ions and specific optical characteristics. In this study, we chose GdVO4 codoped with Eu3+ and Bi3+ as the host material to generate a highly efficient contrast agent (CA) for MRI and long-term luminescence imaging. The new CA emits strong and stable luminescence because of its strong characteristic emissions, resulting from the energy-transfer process from the vanadate groups (VO4 3-) to the Eu3+ and Bi3+ dopants. Additionally, these NPs provided conspicuous T 1 and T 2 relaxation time-shortening characteristics, which result in MRI enhancement. GdVO4:Eu3+,Bi3+ NPs were tested on liver tumor-bearing nude mice, and showed improved liver tumor contrast in T 2-weighted MR images (T 2WI). The dual-modal imaging probe exhibited no cytotoxicity or organ toxicity, reflecting its excellent biocompatibility. Thus, GdVO4:Eu3+,Bi3+ has the potential to be used for bioassays in vitro and liver tumor targeting in vivo. The results reveal the great promise of using the designed GdVO4:Eu3+,Bi3+ NPs as luminescent and MRI dual-mode bioprobes for clinical bioimaging applications.

1H NMR Relaxometric Analysis of Paramagnetic Gd2O3:Yb Nanoparticles Functionalized with Citrate Groups

Gd2O3 nanoparticles doped with different amount of Yb3+ ions and coated with citrate molecules were prepared by a cheap and fast co-precipitation procedure and proposed as potential “positive” contrast agents in magnetic resonance imaging. The citrate was used to improve the aqueous suspension, limiting particles precipitation. The relaxometric properties of the samples were studied in aqueous solution as a function of the magnetic field strength in order to evaluate the interaction of the paramagnetic ions exposed on the surface with the water molecules in proximity. The nanoparticles showed high relaxivity values at a high magnetic field with respect to the clinically used Gd3+-chelates and comparable to those of similar nanosytems. Special attention was also addressed to the investigation of the chemical stability of the nanoparticles in biological fluid (reconstructed human serum) and in the presence of a chelating agent.

Co-delivery of docetaxel and gemcitabine by anacardic acid modified self-assembled albumin nanoparticles for effective breast cancer management

In the present study, we have modified bovine serum albumin (BSA) by covalently conjugating with anacardic acid (AA) and gemcitabine (GEM) and further used for development of docetaxel (DTX) loaded nanoparticles (AA-GEM-BSA NPs). AA is supposed to provide tumor targeting through VEGF receptors overexpressed in tumors, while the combination of GEM and DTX is supposed to provide synergistic activity by targeting multiple pathways. The conjugate was synthesized via carbodiimide chemistry and characterized by ¹H NMR, FTIR, MALDI-TOF and elemental analysis. Conformational changes owing to conjugation of AA and GEM were estimated via fluorescence, Raman and CD spectroscopy, while changes in physiochemical properties were studied by differential scanning calorimetry (DSC), thermogravimetry (TGA) and contact angle goniometry (CAG). Synthesized conjugate was further transformed into DTX loaded NPs and freeze dried. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) demonstrated formation of spherical NPs having particle size, 163 ± 8 nm, PDI, 0.13 ± 0.09 and ZP, -27 ± 1 mV. Cellular uptake in MCF-7 and MDA-MB-231 revealed hNTs, OATP1B3 independent, clathrin mediated internalization followed via nuclear co-localization of C-6 loaded AA-GEM-BSA NPs, responsible for significantly higher apoptosis index. Pharmacokinetic profile of DTX loaded AA-GEM-BSA NPs revealed 6.12 and 3.27-fold and 6.28 and 8.9-fold higher AUC and T_1/2 values of DTX and GEM as compared to Taxotere® and Gemzar®, respectively. Interestingly, the developed NPs were found safe with no marked effect on RBCs, lower hepato and nephro toxicity. Data in hand suggest promising potential of developed NPs in ameliorating the pharmacokinetic and therapeutic profile of combinatorial regimen of DTX and GEM.

STATEMENT OF SIGNIFICANCE

The present report is the original state of art technology to selectively target dual drug (DTX and GEM) loaded BSA NPs via exploring tumor targeting potential of AA, having high affinity towards VEGF receptors (angiogenesis marker) overexpressed in tumor. The AA and GEM bio-conjugated BSA was synthesized and further used to develop DTX loaded nanoparticles (AA-GEM-BSA NPs). The optimized NPs were further evaluated via extensive in vitro and in vivo studies, demonstrating ameliorated cellular uptake, pharmacokinetic and toxicity profile of drugs. Conclusively, DTX loaded AA-GEM-BSA NPs, holds promising potential in increasing the therapeutic efficiency of drugs and overcoming solvent and drug mediated side effects and can be explored further as a scalable platform technology for difficult to deliver drugs.

Impact of albumin based approaches in nanomedicine: Imaging, targeting and drug delivery

A major challenge in the field of nanomedicine is to transform laboratory innovations into commercially successful clinical products. In this campaign, a variety of nanoenabled approaches have been designed and investigated for their role in biomedical applications. The advantages associated with the unique structure of albumin imparts it with the ability to interact with variety of molecules, while the functional groups present on their surface provide base for large number of modifications making it as an ideal nanocarrier system. So far, a variety of albumin based nanoenabled approaches have been intensively exploited for effective diagnosis and personalized medicine, among them some have successfully completed their journey from lab bench to marketed products. This review focuses on the recent most promising advancement in the field of albumin based nanoenabled approaches for various biomedical applications and their potential use in cancer diagnosis and therapy.

Albumin Carriers for Cancer Theranostics: A Conventional Platform with New Promise

Theranostic nanoplatforms with integrated diagnostic and therapeutic functions, aiming at imaging-guided therapy to improve treatment planning, as well as combination therapy to enhance treatment efficacy, have received tremendous attention in recent years. Among numerous types of functional nanomaterials explored in this field, protein-based nanocarriers with inherent biocompatibility have also been selected as building blocks to construct multifunctional theranostic platforms. In particular, albumin, which has been extensively used as drug-delivery carriers for decades, has shown great new promise in the construction of novel imaging and therapeutic nanoagents, as demonstrated by a number of recent studies. IHere, the motivations of using albumins to build up nanoscale theranostics are discussed, and the latest progress/future perspectives in this direction are summarized.