Nanomaterials for Diagnosis and Treatment of Brain Cancer: Recent Updates

Brain tumors, especially glioblastoma, remain the most aggressive form of all the cancers because of inefficient diagnosis and profiling. Nanostructures, such as metallic nanostructures, silica nano-vehicles, quantum dots, lipid nanoparticles (NPs) and polymeric NPs, with high specificity have made it possible to permeate the blood–brain barrier (BBB). NPs possess optical, magnetic and photodynamic properties that can be exploited by surface modification, bio composition, contrast agents’ encapsulation and coating by tumor-derived cells. Hence, nanotechnology has brought on a revolution in the field of diagnosis and imaging of brain tumors and cancers. Recently, nanomaterials with biomimetic functions have been introduced to efficiently cross the BBB to be engulfed by deep skin tumors and cancer malignancies for imaging. The review focuses on nanotechnology-based diagnostic and imaging approaches for exploration in brain tumors and cancers. Moreover, the review also summarizes a few strategies to image glioblastoma and cancers by multimodal functional nanocomposites for more precise and accurate clinical diagnosis. Their unique physicochemical attributes, including nanoscale sizes, larger surface area, explicit structural features and ability to encapsulate diverse molecules on their surface, render nanostructured materials as excellent nano-vehicles to cross the blood–brain barrier and convey drug molecules to their target region. This review sheds light on the current progress of various kinds of nanomaterials, such as liposomes, nano-micelles, dendrimers, carbon nanotubes, carbon dots and NPs (gold, silver and zinc oxide NPs), for efficient drug delivery in the treatment and diagnosis of brain cancer.

Microwave-Synthesized Polysaccharide-Derived Carbon Dots as Therapeutic Cargoes and Toughening Agents for Elastomeric Gels

Fluorescent carbon dots (CDs) play a versatile role in materials science. Herein, we have developed alginate-derived nitrogen-doped CDs as a drug carrier and a toughening agent for hydrogels by a microwave-assisted method. In the first phase of work, we carried out covalent conjugation of the drug onto the CD surface for controlled delivery of drug molecules, and in the second phase of work, we demonstrated how CDs could act as a toughening agent as well as a viscosity modifier for poly(acrylic acid-co-methacrylamide) copolymer hydrogels. The hydrogels were evaluated by Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, and solid-state nuclear magnetic resonance. The hybrid hydrogels have been tested to be mechanically robust with extraordinary stretchability (∼1200% elongation at break), recoverable to the original position (low permanent set), tunable water uptake, and thixotropic character in dynamic stress. The crosslinked structure has been evaluated through void calculation revealing gradual densification of the network with increasing CD content. Exceptional gel strength (ratio of elastic modulus to loss modulus; G'/G″) has been achieved from analogous crosslinking made by CDs. The delayed network rupturing and superstretchability could make this material a good choice for soft biomaterials and soft robotics.

High drug-loading system of hollow carbon dots-doxorubicin: preparation, in vitro release and pH-targeted research

Hollow carbon dots (HCDs), as drug carriers, and doxorubicin (DOX), as a model drug, were selected to prepare a HCDs-DOX-loading system. First, HCDs were prepared by a hydrothermal method and characterized by transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and nuclear magnetic resonance (¹³C NMR), UV-vis absorption, Fourier-transform infrared (FT-IR) and X-ray photoelectron spectroscopies (XPS). The HCDs were then used to load DOX. The drug-loading system of HCDs-DOX was characterized by zeta potential measurements, and UV-vis absorption and fluorescence spectroscopies. We then studied the drug loading, formation mechanism, cytotoxicity, in vitro release and pH-targeted properties. HCDs-DOX was found to have a high drug (DOX)-loading ratio (∼42.9%) and better sustained pH targeted-release and lower cytotoxicity than those of DOX. In the HCDs-DOX system, interactions between the HCDs and DOX were electrostatic resulting in the formation of -N[double bond, length as m-dash]C-via the coupling of -NH₂ (on HCDs) and -C[double bond, length as m-dash]O (on DOX). In vitro release of HCDs-DOX conformed to the Weibull model and Fick diffusion, consistent with that of free DOX. We report, for the first time, that the: (i) functional groups on the HCD surfaces (not their hollow structure) play a key role in drug loading; (ii) the carrier (HCDs) did not change the in vitro release model or mechanism of DOX before and after loading by the HCDs.

Biofunctionalized MnFe2O4@Au core-shell nanoparticles for pH-responsive drug delivery and hyperthermal agent for cancer therapy

Novel materials are explored very often by material scientists to design an efficient drug delivery system to target carcinoma cells. Among various nanosystem, functionalized Iron oxide Nanoparticles (IoNP) were definitely studied especially to target, endocyte and release drug moieties inside the cells. This IoNP platform is usually composed of an inorganic core and a highly biocompatible shell layer in order to perform numerous tasks at the same time, such as drug delivery, multimodal imaging, and instantaneous monitoring, along with collective therapeutic approaches. Hence, in this work, MnFe₂O₄@Au nanoparticles (Mf@A) are used as a structure for docking anti-cancer drug using a coupling molecule for the precise targeting. The formation of the core-shell structure was corroborated by high-angle annular dark-field scanning transmission electron microscopy and line mapping techniques. Superconducting quantum interference device confirms the fabricated nanostructure is favorably superparamagnetic. The stability of nanoparticles was examined by measuring the zeta-potential measurements. The binding efficiency of the drug onto the Mf@A was found to be >90%. Drug-release was carried out at different pH and found that the release is maximum at lower pH. Finally, at 2.45 GHz we employed as a magneto-hyperthermal agent which produced heat to kill the cancerous cell.

Porphyrin-Gold Nanomaterial for Efficient Drug Delivery to Cancerous Cells

With an aim to overcome multidrug resistance (MDR), nontargeted delivery, and drug toxicity, we developed a new nanochemotherapeutic system with tetrasodium salt of meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) armored on gold nanoparticles (TPPS-AuNPs). The nanocarrier is able to be selectively internalized within tumor cells than in normal cells followed by endocytosis and therefore delivers the antitumor drug doxorubicin (DOX) particularly to the nucleus of diseased cells. The embedment of TPPS on the gold nanosurface provides excellent stability and biocompatibility to the nanoparticles. Porphyrin interacts with the gold nanosurface through the coordination interaction between gold and pyrrolic nitrogen atoms of the porphyrin and forms a strong association complex. DOX-loaded nanocomposite (DOX@TPPS-AuNPs) demonstrated enhanced cellular uptake with significantly reduced drug efflux in MDR brain cancer cells, thereby increasing the retention time of the drug within tumor cells. It exhibited about 9 times greater potency for cellular apoptosis via triggered release commenced by acidic pH. DOX has been successfully loaded on the porphyrin-modified gold nanosurface noncovalently with high encapsulation efficacy (∼90%) and tightly associated under normal physiological conditions but capable of releasing ∼81% of drug in a low-pH environment. Subsequently, DOX-loaded TPPS-AuNPs exhibited higher inhibition of cellular metastasis, invasion, and angiogenesis, suggesting that TPPS-modified AuNPs could improve the therapeutic efficacy of the drug molecule. Unlike free DOX, drug-loaded TPPS-AuNPs did not show toxicity toward normal cells. Therefore, higher drug encapsulation efficacy with selective targeting potential and acidic-pH-mediated intracellular release of DOX at the nucleus make TPPS-AuNPs a "magic bullet" for implication in nanomedicine.

Bioformulation of silver nanoparticles as berberine carrier cum anticancer agent against breast cancer

The present work focuses on the bioformulation of AgNPs as a carrier for berberine and tests whether biogenic AgNPs elicit anticancer activity against breast cancer.

Plasmonic/Magnetic Multifunctional nanoplatform for Cancer Theranostics

A multifunctional magneto-plasmonic CoFe2O4@Au core-shell nanoparticle was developed by iterative-seeding based method. This nanocargo consists of a cobalt ferrite kernel as a core (Nk) and multiple layers of gold as a functionalizable active stratum, (named as Nk@A after fifth iteration). Nk@A helps in augmenting the physiological stability and enhancing surface plasmon resonance (SPR) property. The targeted delivery of Doxorubicin using Nk@A as a nanopayload is demonstrated in this report. The drug release profile followed first order rate kinetics optimally at pH 5.4, which is considered as an endosomal pH of cells. The cellular MR imaging showed that Nk@A is an efficient T2 contrast agent for both L6 (r2-118.08 mM-1s-1) and Hep2 (r2-217.24 mM-1s-1) cells. Microwave based magnetic hyperthermia studies exhibited an augmentation in the temperature due to the transformation of radiation energy into heat at 2.45 GHz. There was an enhancement in cancer cell cytotoxicity when hyperthermia combined with chemotherapy. Hence, this single nanoplatform can deliver 3-pronged theranostic applications viz., targeted drug-delivery, T2 MR imaging and hyperthermia.

Green Synthetic Approach for Synthesis of Fluorescent Carbon Dots for Lisinopril Drug Delivery System and their Confirmations in the Cells

In this work, highly luminescent carbon dots (CDs) were synthesized by the hydrothermal method at 170 °C for 12 h using pasteurized milk as a carbon source. The prepared CDs exhibited bright blue fluorescence under UV light illumination at 365 nm. The CDs show fluorescence life time of ~4.89 ns at excitation wavelength of 370 nm. The effect of different solvents on the fluorescence property of CDs was also investigated. The lisinopril (Lis)-loaded CDs were fabricated by self-assembly of lisinopril on the surfaces of CDs, which were characterized by UV-visible and FT-IR spectroscopic techniques. The controlled release of lisinopril from the Lis-CDs was realized at pH values of 5.2, 6.2 and 7.4, respectively. The results of the cytotoxicity and confocal laser scanning microscopic images indicate that the Lis-CDs were successfully uptaken by HeLa cells without apparent cytotoxicity. The synthesized CDs show great potential as drug vehicles with good biocompatibility, sustained release of lisinopril from CDs, indicating that the CDs can act as a promising drug delivery system for therapeutic delivery and/or bioimaging applications.

Doxorubicin-Incorporated Nanotherapeutic Delivery System Based on Gelatin-Coated Gold Nanoparticles: Formulation, Drug Release, and Multimodal Imaging of Cellular Internalization

In this work, we developed a new pH- and temperature-responsive nanochemotherapeutic system based on Doxorubicin (DOX) noncovalently bound to biosynthesized gelatin-coated gold nanoparticles (DOX-AuNPs@gelatin). The real-time release profile of DOX was evaluated at different pH values (7.4, 5.3, and 4.6) and temperatures (22-45 °C) in aqueous solutions, and its therapeutic performance was examined in vitro against MCF-7 breast cancer cells. TEM, dark-field scattering, and wide-field fluorescence microscopy indicated the effective uptake of nanochemotherapeutics with the subsequent release and progressive accumulation of DOX in cell nuclei. MTT assays clearly showed the effectiveness of the treatment by inhibiting the growth of MCF-7 breast cancer cells for a loaded drug concentration of 5 μg/mL. The most informative data about the dynamic release and localization were provided by scanning confocal microscopy using time-resolved fluorescence and surface-enhanced Raman scattering (SERS) techniques. In particular, fluorescence-lifetime imaging (FLIM) recorded under 485 nm pulsed diode laser excitation revealed the bimodal distribution of DOX in cells. The shorter fluorescence lifetime of DOX localized in nuclei (1.52 ns) than in the cytoplasm (2.4 ns) is consistent with the cytotoxic mechanism induced by DOX-DNA intercalation. Remarkably, the few DOX molecules captured between nanoparticles ("electromagnetic hotspots") after most drug is released act as SERS reporters for the localization of plasmonic nanocarriers in MCF-7 cells. The high drug loading capacity and effective drug release under pH control combined with the advantage of multimodal visualization inside cells clearly indicate the high potential of our DOX-AuNPs@gelatin delivery system for implementation in nanomedicine.

Synthesis of mesoporous titanium oxide for release control and high efficiency drug delivery of vinorelbine bitartrate

Schematic illustration of porous titanium oxide for drug delivery of vinorelbine bitartrate.

Ultrafast synthesis of stabilized gold nanoparticles using aqueous fruit extract of Limonia acidissima L. and conjugated epirubicin: targeted drug delivery for treatment of breast cancer

Green synthesis of AuNPs using extract ofLimonia acidissimaL. as a reducing agent. Epirubicin was successfully loaded on folic acid–AuNPs. This formulation revealed better site specific delivery of epirubicin to MCF-7 cells.

Phytosynthesis of gold nanoparticles using Mappia foetida leaves extract and their conjugation with folic acid for delivery of doxorubicin to cancer cells

Mappia foetida leaves extract is used as bioreductant for the synthesis of gold nanoparticles and their application in the efficient delivery of doxorubicin to human cancer cells is reported here. The formation of gold nanoparticles is evident from their characteristic optical absorption at ~560 nm. X-ray diffraction pattern of gold nanoparticles confirmed their fcc structure. Fourier transform infrared spectroscopy shows the bioactive molecules from plant extract capped on the surface of gold nanoparticles and conjugation of doxorubicin along with activated folic acid as navigational molecules for targeted drug delivery. Such a conjugation of gold nanoparticles is characterized by their weight loss, ~35-40 %, due to thermal degradation of plant biomass and conjugated drug along with receptor, as observed in thermogravimetric analysis. The spherical shaped gold nanoparticles (Φ 10-20 nm) are observed by field emission scanning electron microscopy and transmission electron microscopy images and the expected elemental composition by energy dispersive X-ray spectroscopy. Gold nanoparticles conjugated with activated folic acid and doxorubicin complex is found to be toxic for human cancer cells viz., MDA-MB-231, HeLa, SiHa and Hep-G2. Furthermore, the amount of drug released was maximum at pH 5.3 (an ambient condition for intravenous cancer drugs) followed by pH 7.2 and pH 6.8.

Folic acid modified copper oxide nanoparticles for targeted delivery in in vitro and in vivo systems

Targeted delivery of copper oxide nanoparticles for breast cancer therapy.

Swarming carbon dots for folic acid mediated delivery of doxorubicin and biological imaging

Carbon dots (C-dots) are one of the most highlighted carbon-based materials for biological applications such as delivery of therapeutic payloads for cancer treatment mainly due to their biocompatibility and unique optical properties. In this work, we have explored the drug carrying capacity of highly fluorescent sorbitol-derived C-dots for targeted delivery of doxorubicin (DOX). We have used folic acid (FA) as a navigational molecule due to its high expression in most cancer cells. Before attachment of the DOX, the surfaces of the C-dots were protected with bovine serum albumin (BSA) to make them more biocompatible and able to hold a high amount of drugs. The release profile of DOX was studied using standard statistical models and confirmed to be first order at pH 7.2. Cellular imaging was performed using epifluorescence microscopy, which showed bright green coloured fluorescence due to internalization of C-dots specifically targeted with FA in HeLa cells.

Carbon dots functionalized gold nanorod mediated delivery of doxorubicin: tri-functional nano-worms for drug delivery, photothermal therapy and bioimaging

Carbon dots (C-dots) are novel nanomaterials for biological applications owing to their inherent surface decoration by a variety of functional groups, excellent fluorescent properties and biocompatibility under physiological conditions. Gold nanorods (GNRs) are one of the most celebrated nanomaterials for photothermal therapy as well as delivery of therapeutic payloads because of their typical size and shape related features. We have synthesized a unique blend of C-dots and GNRs (C-dots@GNRs) for the controlled release of doxorubicin (DOX) under ideal physiological conditions. Highly fluorescent C-dots were synthesized using microwave assisted heating of gum arabic (GA) and subsequently purified using Sucrose Density Gradient Centrifugation (SDGC). In a modified seed mediated protocol, purified C-dots were added into the growth solution, to make a C-dots@GNR complex. This complex was used for anchoring DOX via covalent and non-covalent pH sensitive chemical bonds. Under physiological conditions, the drug loading capacity of C-dots@GNRs was calculated to be ∼94%. Another beneficial attribute of the complex was found to be synergistic potential in high drug loading and rapid burst of drug release under the influence of near infrared (NIR) radiation (808 nm), thus proving a highly biocompatible thermo-chemotherapy for solid tumors.

Gold nanorods mediated controlled release of doxorubicin: nano-needles for efficient drug delivery

Use of cysteamine hydrochloride (Cys-HCl) protected gold nanorods (GNRs) as efficient carrier of widely used anti-cancer drug doxorubicin using folic acid as navigational molecule is presented in this work. GNRs were found to have excellent drug loading capacity of >97 %. A detailed comprehension of in vitro drug release profile under ideal physiological condition was found to obey 1st order kinetics at pH 6.8, 5.3 and 7.2, an ideal milieu for drug delivery to solid tumours.

A comparative study of economical separation and aggregation properties of biologically capped and thiol functionalized gold nanoparticles: selecting the eco-friendly trojan horses for biological applications

We are presenting facile bio-fabrication of extremely stable gold nanoparticles (GNPs) using medicinal plant Azadirachta indica (commonly called Neem) and its comparison with most commonly used glutathione (GSH) protected GNPs in terms of stability under physiological conditions, seperation using density gradient centrifugation and aggregation properties in the solution. There was dual peak at 536 and 662 nm indicating the presence of non-spherical GNPs including triangles, rods and hexagons in case of A. indica mediated GNPs unlike citrate stabilized GNPs which exhibited single sharp peak. Spherical GNPs were separated from the consortium of uniquely shaped nanoparticles bio-fabricated using A. indica leaf extract using sucrose density gradient centrifugation (SDGC).To comprehend the anti-agglomeration potentials of A. indica leaf mediated GNPs and GSH-GNPs under physiological conditions, flocculation parameters (FP) were calculated and found to be least for A. indica leaf mediated GNPs, indicating their exceptional stability.