Colloidal stability and physicochemical characterization of bombesin conjugated biodegradable nanoparticles

Nanostrategies for Therapeutic and Diagnostic Targeting of Gastrin-Releasing Peptide Receptor

Advances in nanomedicine bring the attention of researchers to the molecular targets that can play a major role in the development of novel therapeutic and diagnostic modalities for cancer management. The choice of a proper molecular target can decide the efficacy of the treatment and endorse the personalized medicine approach. Gastrin-releasing peptide receptor (GRPR) is a G-protein-coupled membrane receptor, well known to be overexpressed in numerous malignancies including pancreatic, prostate, breast, lung, colon, cervical, and gastrointestinal cancers. Therefore, many research groups express a deep interest in targeting GRPR with their nanoformulations. A broad spectrum of the GRPR ligands has been described in the literature, which allows tuning of the properties of the final formulation, particularly in the field of the ligand affinity to the receptor and internalization possibilities. Hereby, the recent advances in the field of applications of various nanoplatforms that are able to reach the GRPR-expressing cells are reviewed.

Effect of Zn/Sn Ratio on Perovskite Solar Cell Performance Applying Off-Stoichiometric Cu2ZnSnS4/Carbon Hole-Collecting Electrodes

Low-cost inorganic hole-transporting materials (HTMs) accompanied by a printable carbon electrode is an efficient approach to address the limitation of material cost of perovskite solar cells (PSCs) and get this technology closer to commercialization. The present work is focused on optimizing the Zn/Sn ratio of Cu₂ZnSnS₄/carbon hole collectors in n-i-p structured PSCs, where CuInS₂/carbon is applied as the reference hole collector. This composition regulation is a solution to address the challenge of composition-related defects of the Cu₂ZnSnS₄ (CZTS) material. The Zn/Sn ratio was tuned by the initial proportion of the zinc precursor during the nanoparticle (NP) synthesis using a heating-up procedure. It was found that the enhancement of the Zn/Sn ratio leads to a gradual increase of the optical band gap. More importantly, an increased density of B-type defect clusters [2Zn_Cu + Zn_Sn] is confirmed using Raman results. Additionally, results from the cyclic voltammetry measurement show that by increasing the Zn/Sn value, the highest occupied molecular orbital (HOMO) of HTM is pulled down. These data match the upward trend of photovoltage. CZTS HTM with an optimal Zn/Sn ratio of 1.5 has a compatible energy level, along with the features of uniform and smooth coverage. The best efficiency of about 14.86% was obtained for optimal CZTS/carbon-based PSCs, which reaches from 14.86 to 15.49% after 25 days of aging.

Self-assembled and pH-responsive polymeric nanomicelles impart effective delivery of paclitaxel to cancer cells

Chemotherapy is an essential component of breast cancer therapy, but it is associated with serious side effects. Herein, a pluronic F68-based pH-responsive, and self-assembled nanomicelle system was designed to improve the delivery of paclitaxel (PTX) to breast cancer cells. Two pH-responsive pluronic F68-PTX conjugates i.e. succinoyl-linked conjugate (F68-SA-PTX) and cis-aconityl-linked conjugate (F68-CAA-PTX) were designed to respond the varying pH-environment in tumour tissue. Although both the linkers showed pH-sensitivity, the F68-CAA-PTX exhibited superior pH-sensitivity over the F68-SA-PTX and achieved a more selective release of PTX from the self-assembled nanomicelles. The prepared nanomicelles were characterized by dynamic light scattering, transmittance electron microscopy, differential scanning calorimetry and powder X-ray diffraction techniques. The anticancer activity of prepared nanomicelles and pure PTX were evaluated by 2D cytotoxicity assay against breast cancer cell line MDA-MB-231 and in the real tumour environments i.e. 3D tumor spheroids of MDA-MB-231 cells. The highest cytotoxicity effect of PTX was observed with F68-CAA-PTX nanomicelles followed by F68-SA-PTX and free PTX. Further, the F68-CAA-PTX nanomicelles also induced significant apoptosis with a combination of increase in ROS generation, decrease in the depolarisation of MMP and G2/M cell cycle arrest. These observed results provide a new insight for breast cancer treatment using pluronic nanomicelles.

Water-Soluble Chitosan Conjugated DOTA-Bombesin Peptide Capped Gold Nanoparticles as a Targeted Therapeutic Agent for Prostate Cancer

Introduction

Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1–14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy.

Methods

The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN.

Results

The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP).

Discussion

The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding ¹⁹⁸AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.

Tailoring functional nanostructured lipid carriers for glioblastoma treatment with enhanced permeability through in-vitro 3D BBB/BBTB models

The blood-brain barrier (BBB) and blood-brain tumour barrier (BBTB) pose a significant challenge to drug delivery to brain tumours, including aggressive glioblastoma (GB). The present study rationally designed functional nanostructured lipid carriers (NLC) to tailor their BBB penetrating properties with high encapsulation of CNS negative chemotherapeutic drug docetaxel (DTX). We investigated the effect of four liquid lipids, propylene glycol monolaurate (Lauroglycol® 90), Capryol® propylene glycol monocaprylate, caprylocaproylmacrogol-8-glycerides (Labrasol®) and polyoxyl-15-hydroxystearate (Kolliphor® HS15) individually and in combination to develop NLCs with effective permeation across in-vitro 3D BBB model without alteration in the integrity of the barrier. With desirable spherical shape as revealed by TEM and an average particle size of 123.3 ± 0.642 nm and zeta potential of -32 mV, DTX-NLCs demonstrated excellent stability for six months in its freeze-dried form. The confocal microscopy along with flow cytometry data revealed higher internalisation of DTX-NLCs in U87MG over SVG P12 cells. Micropinocytosis was observed to be one of the dominant pathways for internalisation in U87MG cells while clathrin-mediated pathway was more predominat in patient-derived glioblastoma cells. The NLCs readily penetrated the actively proliferating peripheral cells on the surface of the 3D tumour spheroids as compared to the necrotic core. The DTX-NLCs induced cell arrest through G2/M phase with a significant decrease in the mitochondrial reserve capacity of cells. The NLCs circumvented BBTB with high permeability followed by accumulation in glioblastoma cells with patient-derived cells displaying ~2.4-fold higher uptake in comparison to U87MG when studied in a 3D in-vitro model of BBTB/GB. We envisage this simple and industrially feasible technology as a potential candidate to be developed as GB nanomedicine.

Rising horizon in circumventing multidrug resistance in chemotherapy with nanotechnology

Multidrug resistance (MDR) is one of the key barriers in chemotherapy, leading to the generation of insensitive cancer cells towards administered therapy. Genetic and epigenetic alterations of the cells are the consequences of MDR, resulted in drug resistivity, which reflects in impaired delivery of cytotoxic agents to the cancer site. Nanotechnology-based nanocarriers have shown immense shreds of evidence in overcoming these problems, where these promising tools handle desired dosage load of hydrophobic chemotherapeutics to facilitate designing of safe, controlled and effective delivery to specifically at tumor microenvironment. Therefore, encapsulating drugs within the nano-architecture have shown to enhance solubility, bioavailability, drug targeting, where co-administered P-gp inhibitors have additionally combat against developed MDR. Moreover, recent advancement in the stimuli-sensitive delivery of nanocarriers facilitates a tumor-targeted release of the chemotherapeutics to reduce the associated toxicities of chemotherapeutic agents in normal cells. The present article is focused on MDR development strategies in the cancer cell and different nanocarrier-based approaches in circumventing this hurdle to establish an effective therapy against deadliest cancer disease.

Bombesin conjugated solid lipid nanoparticles for improved delivery of epigallocatechin gallate for breast cancer treatment

Epigallocatechin-gallate (EGCG) is a potent anti-cancer therapeutic which effectively controls the growth of cancerous cells through a variety of different pathways. However, its molecular structure is susceptible to modifications due to cellular enzymes affecting its stability, bioavailability and hence, overall efficiency. In this study, we have initially encapsulated EGCG in the matrix of solid lipid nanoparticles to provide a stable drug carrier. To confer additional specificity towards gastrin releasing peptide receptors (GRPR) overexpressed in breast cancer, EGCG loaded nanoparticles were conjugated with a GRPR-specific peptide. In-vitro cytotoxicity studies showed that the peptide-conjugated formulations possessed greater cytotoxicity to cancer cell lines compared to the non-conjugated formulations. Further, in-vivo studies performed on C57/BL6 mice showed greater survivability and reduction in tumour volume in mice treated with peptide-conjugated formulation as compared to the mice treated with non-conjugated formulation or with plain EGCG. These results warrant the potential of the system designed in this study as a novel and effective drug delivery system in breast cancer therapy.

Designing of fatty acid-surfactant conjugate based nanomicelles of morin hydrate for simultaneously enhancing anticancer activity and oral bioavailability

Morin hydrate (MH) is a naturally occurring polyphenolic flavonol compound. It has been recently investigated for its many biological activities such as anti-inflammatory, anticancer, antioxidant, antiarthritic, antifertility, antiplasmodic and anticancer. Though these outcomes are very promising, its low aqueous solubility and oral bioavailability restrict its clinical uses. Therefore, in this study we report pluronic F68 and stearic acid conjugated (F68-SA) nanomicelles for increasing oral bioavailability of MH. The MH loaded F68-SA nanomicelles (MHNM) were prepared by the solvent evaporation method. The MHNM were extensively characterized for the size, surface charge, stability, morphology, critical micelle concentration, drug content, and in-vitro drug release. The cell viability assay depicted a significant increase in cytotoxicity of MH against A549 human lung cancer cells after incubating as MHNM. Exposure of A549 cells to MHNM induced cell apoptosis in the cells as observed in apoptosis studies. Pharmacokinetic studies in Sprague-Dawley rats revealed that MHNM significantly increased the oral bioavailability of MH as compared to pure drug. Therefore, the novel, surfactant-lipid based micellar system is an effective solubilizing and delivering system for oral administration of poorly water soluble drugs like MH.

Determination of solubility, stability and degradation kinetics of morin hydrate in physiological solutions

Natural drugs have emerged as potential alternatives to synthetic drugs to avoid their toxic effects. Morin hydrate (MH) is a natural therapeutic agent, obtained from Maclura pomifera, Maclura tinctoria and Psidium guajava. Solubility and degradation kinetics of morin hydrate in different physiological media, namely, 0.1 N HCl (pH 1.2), sodium acetate buffer (pH 5.0), water (pH 7.0), phosphate buffer saline (pH 7.4) and tris base (pH 9.0), were investigated via classical spectroscopic methods. Stability studies of MH were performed to determine the effect of different pH media, temperature (room and freeze) and light on the degradation kinetics. Solubility and stability of MH varied significantly in different biological media and storage conditions. Solubility of MH was pH-dependent and increased with the increase in pH. Degradation kinetics and regression values (r²) values were calculated from the linear fitted models of zero, first and second order kinetics.

The stability of morin hydrate depends on pH, temperature, and light.

Size optimization and in vitro biocompatibility studies of chitosan nanoparticles

Chitosan (CS), an amino polysaccharide has fascinating scientific applications due to its many flexible properties. The advantages of Chitosan tend to increase when it was modified. Thus, in the present research work, to improve the properties of chitosan, it was converted into chitosan nanoparticles (CS-NPs) through the ionic gelation method using sodium tripoyphosphate (TPP) and sodium hexametaphosphate (SHMP) as a crosslinker. The size optimization was done by varying the parameters such as crosslinker concentration, agitation method and rate, agitation time, temperature and drying method. The prepared samples were characterized using FTIR, TGA, XRD, SEM, TEM and DLS. Also the prepared CS-NPs with TPP and SHMP had been evaluated in vitro for determining its hemocompatibility, biodegradability, serum stability, cytotoxicity and cell viability. The results showed the significant participation of all the parameters in obtaining the nanoparticles in 20-30nm and 5-10nm for CS-NPs-TPP air dried and freeze dried samples and around 60-80nm and 20-30nm for CS-NPs-SHMP air dried and freeze dried samples. The in vitro biological studies revealed that the nanoparticles are non-toxic with a good degree of biodegradability, blood compatibility and stability.

Anti prostate cancer using PEGylated bombesin containing, cabazitaxel loading nano-sized drug delivery system

CONTEXT

Prostate cancer (PCa) is the second most-frequently diagnosed cancer in men. Cabazitaxel was approved for the treatment of patients with hormone-refractory metastatic prostate cancer previously treated with a docetaxel-containing regimen.

OBJECTIVE

In this study, bombesin (BN), a ligand reported to specifically target GRP overexpressing prostate tumor, was applied for the construction of lipid-polymer hybrid nanoparticles (LPNs), and used for the targeted delivery of cabazitaxel (CAB) to prostate cancer.

METHODS

BN-polyethylene glycol-1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (BN-PEG-DSPE) was synthesized. CAB loaded, BN-PEG-DSPE contained LPNs (BN-CAB-LPNs) were prepared. Their particle size, zeta potential and drug encapsulation efficiency (EE) were evaluated. In vitro cytotoxicity study of BN-CAB-LPNs was tested in LNCaP human prostatic cancer cell line (LNCaP cells). In vivo anti-tumor efficacy of the carriers was evaluated on mice bearing prostate cancer model.

RESULTS

The optimum BN-CAB-LPNs formulations had a particle size of 184.9 nm and a 26.5 mV positive surface charge. The growth of LNCaP cells in vitro was obviously inhibited. BN-CAB-LPNs also displayed better anti-tumor activity than the other formulations in vivo.

CONCLUSION

The results demonstrated that BN-CAB-LPNs can sufficiently deliver CAB to the cancer cells and enhance the anti-tumor capacity. Thus, BN-CAB-LPNs can be proved to be a superior nanomedicine which can achieve better therapeutic efficacy of prostate tumor.

Characterization, biorecognitive activity and stability of WGA grafted lipid nanostructures for the controlled delivery of Rifampicin

Targeted nanomedicines improve the delivery of drugs by increasing the drug concentration at target site, protecting the premature degradation and releasing the encapsulated drug in controlled manner. To make rifampicin (RFN) delivery more effective, we designed and characterized wheat germ agglutinin (WGA) conjugated, RFN loaded solid-lipid nanoparticles (WRSN). Nanoparticles were prepared by solvent emulsification/evaporation and conjugated with fluorescein isothiocyanate-labeled WGA. Important characteristics, such as particle size, zeta potential, encapsulation efficiency, conjugation efficiency and in vitro drug release behavior, were investigated. WGA conjugation to the nanoparticles was confirmed by Fourier Transform Infrared (FTIR) analysis. Conjugation efficiency was determined by fluorescent spectroscopy and Bradford assay. RFN was released from nanoparticles via the diffusion-controlled, non-fickian and supercase II mechanism. A haemaglutination test confirmed that WGA retained its bio-recognition activity and sugar-binding specificity after it was coupled with the nanoparticles. In vitro experiments demonstrated that WRSN interacted more than non-conjugated nanoparticles with porcine mucin. WRSN were stable in the presence of electrolytes up to 1M concentration. Therefore, WGA-conjugated solid lipid nanoparticles could be a promising tool for the controlled delivery of RFN or other anti-tubercular drugs.

Bombesin-conjugated nanoparticles improve the cytotoxic efficacy of docetaxel against gastrin-releasing but androgen-independent prostate cancer

Aim: Bombesin (BBN)-conjugated polymeric nanoparticles to target docetaxel (DTX) to prostate cancer cells that overexpress gastrin-releasing peptides receptors. Materials & methods: In vitro cytotoxicity, uptake of nanoparticles and inhibition of cell migration were assessed against human prostate cancer cells. Preclinical pharmacokinetic and tissue-distribution studies of nanoparticles were performed in Balb/c mice and results compared with the marketed formulation Taxotere®. Results: BBN-conjugated DTX-loaded nanoparticles exhibited higher cytotoxicity, inhibition of cell migration and colony formation than non-targeted nanoparticles or DTX alone. More BBN-conjugated nanoparticles were taken up at a faster rate than unconjugated nanoparticles. In vivo, this drug delivery improved pharmacokinetics of DTX by increasing mean residence time and decreasing clearance. Conclusion: This study provides an alternate approach for polysorbate-free delivery of DTX, with improved in vivo performance.

Nanomedicines for targeted delivery of etoposide to non-small cell lung cancer using transferrin functionalized nanoparticles

Tf-conjugated solid lipid nanoparticles were designed for selectively targeting etoposide to human non-small cell lung cancer resulting in sustained drug release, improved plasma concentrations and accumulation of etoposide in targeted lung tissues.

Fabrication, characterization and bioevaluation of silibinin loaded chitosan nanoparticles

Silibinin is reported to possess multiple biological activities. However, its hydrophobic nature limits its bioavailability compromising in vivo biological activities. Nanoparticles-based delivery of such molecules has emerged as new technique to resolve these issues. Bio-degradable, compatible and adhesive nature of chitosan has recently attracted its suitability as a carrier for biologically active molecules. This study presents fabrication and characterization of chitosan-tripolyphosphate based encapsulation of silibinin. Various preparations of silibinin encapsulated chitosan-tripolyphosphate nanoparticles were studied for particle size, morphology, zeta-potential, and encapsulation efficiencies. Preparations were also evaluated for cytotoxic activities in vitro. The optimized silibinin loaded chitosan nanoparticles were of 263.7±4.1nm in particle size with zeta potential 37.4±1.57mV. Nanoparticles showed high silibinin encapsulation efficiencies (82.94±1.82%). No chemical interactions between silibinin and chitosan were observed in FTIR analysis. Powder X-ray diffraction analysis revealed transformed physical state of silibinin after encapsulation. Surface morphology and thermal behaviour were determined using TEM and DSC analysis. Encapsulated silibinin displayed increased dissolution and better cytotoxicity against human prostate cancer cells (DU145) than silibinin alone.