Multifunctional Liposomes Targeting Amyloid-ß Oligomers for Early Diagnosis and Therapy of Alzheimer's Disease.

Early detection and treatment are crucial for Alzheimer's disease (AD) management. Current diagnostic and therapeutic methods focus on late-stage amyloid fibrils and plaques, overlooking toxic soluble amyloid ß oligomers (AßOs) accumulating early in AD. A multifunctional liposome-based platform is designed for early diagnosis and therapy of AD, leveraging a novel self-assembled cyclic d,l-α-peptide (CP-2) that selectively targets AßOs. Biocompatible CP-2 conjugated liposomes (CP-2-LPs) effectively disrupt Aß aggregation and mitigate Aß-mediated toxicity in human neuroblastoma cells. In transgenic Caenorhabditis elegans AD models, CP-2-LPs significantly outperformed free CP-2 by improving cognitive and behavioral functions, extending lifespan, and reducing toxic AßO levels. Intravenous injection of fluorescently labeled CP-2-LPs reveals effective blood-brain barrier penetration, with significantly higher brain fluorescence in transgenic mice than WT, enabling precise diagnosis. These findings underscore CP-2-LPs as a valuable tool for early detection and targeted therapy in AD.

Early diagnosis and treatment of Alzheimer's disease by targeting toxic soluble Aß oligomers.

Transient soluble oligomers of amyloid-ß (Aß) are toxic and accumulate early prior to insoluble plaque formation and cognitive impairment in Alzheimer's disease (AD). Synthetic cyclic D,L-α-peptides (e.g., 1) self-assemble into cross ß-sheet nanotubes, react with early Aß species (1-3 mers), and inhibit Aß aggregation and toxicity in stoichiometric concentrations, in vitro. Employing a semicarbazide as an aza-glycine residue with an extra hydrogen-bond donor to tune nanotube assembly and amyloid engagement, [azaGly6]-1 inhibited Aß aggregation and toxicity at substoichiometric concentrations. High-resolution NMR studies revealed dynamic interactions between [azaGly6]-1 and Aß42 residues F19 and F20, which are pivotal for early dimerization and aggregation. In an AD mouse model, brain positron emission tomography (PET) imaging using stable 64Cu-labeled (aza)peptide tracers gave unprecedented early amyloid detection in 44-d presymptomatic animals. No tracer accumulation was detected in the cortex and hippocampus of 44-d-old 5xFAD mice; instead, intense PET signal was observed in the thalamus, from where Aß oligomers may spread to other brain parts with disease progression. Compared with standard 11C-labeled Pittsburgh compound-B (11C-PIB), which binds specifically fibrillar Aß plaques, 64Cu-labeled (aza)peptide gave superior contrast and uptake in young mouse brain correlating with Aß oligomer levels. Effectively crossing the blood-brain barrier (BBB), peptide 1 and [azaGly6]-1 reduced Aß oligomer levels, prolonged lifespan of AD transgenic Caenorhabditis elegans, and abated memory and behavioral deficits in nematode and murine AD models. Cyclic (aza)peptides offer novel promise for early AD diagnosis and therapy.

Layered Double Hydroxide Nanoparticles for Efficient Gene Delivery for Cancer Treatment.

The use of cationic polymer based gene delivery vectors has several limitations such as low transfection efficiency, high toxicity, and inactivation by serum. The present work provides an inorganic based nanocarrier for efficient gene delivery and a method for preparing the same through a facile coprecipitation technique. The vehicle showed high loading capacity of DNA and can release the loaded DNA in a controlled pH-responsive manner. The developed gene delivery vehicle offers remarkable protection against DNase I and also provides protection against thermal damage. This vehicle also demonstrated efficient cellular uptake performance. Transfection and expression of plasmid gene encoding GFP proteins is achieved successfully by this LDH based vehicle. More interestingly, the developed Li-Al LDH efficiently induces GFP-p53 mediated apoptosis in HeLa cells exclusively sparing the normal tissue cells like NIH-3T3. The study demonstrates the potential of the developed inorganic based nanocarrier as a promising nonviral gene vector for tumor treatment.

Fluorescent-functionalized graphene oxide for selective labeling of tumor cells.

Fluorescence probe has attracted significant attention for biomedical imaging in recent years due to their high resolution at the cellular level. Organic-based fluorescent probes with high quantum yield are widely applied in bioimaging, but most of them suffer from a serious obstacle called aggregation-caused quenching in cellular systems. New fluorophore has been designed through functionalization of graphene oxide which emphatically exhibits aggregation-induced emission along with pH-responsive nanoprobe. Significantly higher emission of this material in slightly acidic media helps to detect tumor cell by creating a sharp contrast with the image of normal cells. The reason for pH-induced enhanced emission phenomenon is revealed through aggregation of sulfonated species in acidic media. Furthermore, the biocompatible nature of the newly developed material is found to be suitable for its application in biomedical imaging for cancer detection with better accuracy at lower cost. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1917-1924, 2019.

Controlling Drug Delivery Using Nanosheet-Embedded Electrospun Fibers for Efficient Tumor Treatment.

The objective of this study is to fabricate biodegradable polymers into scaffolds to embed drugs for tumor treatment without any toxic side effects. Scaffold preparation is optimized by changing the conditions, e.g., poly(lactic acid) concentration (10% w/v), applied potential (15 kV), flow rate (1 mL/h), distance between needle and collector (20 cm), and nanosheet concentration (4 wt % nanoclay), during electrospinning. A drug-embedded nanofiber scaffold is used to regulate the drug delivery in a sustainable manner utilizing the enhanced barrier effect from dispersed nanosheet and good interaction between the components. The effect of thermal treatment improves the stability and slower release of drug through alteration in microstructure. Cell culture studies using a nanofiber scaffold indicate its biocompatibility and applicability as a biomaterial for tumor treatment. Sustained drug release from the scaffold enhances the in vitro cancer cytotoxicity up to 85% in 3 days. In vivo studies clearly suggest suppression of tumor volume using scaffold as a patch over the tumor site as compared to control, pure drug, and drug-embedded film in the mice model. Evaluation of biochemical parameters indicates no toxic side effects for the liver and kidney using a hybrid scaffold as a delivery vehicle as opposed to severe liver injury in control and pure drug-treated mice group. Histopathology of the organs confirms the side effects for the pure drug-treated mice group against normal tissue morphology observed in scaffold-treated animals. Thus, sustained release of drug from this novel delivery vehicle has every potential to be used for tumor treatment more efficiently without any considerable side effects.

Controlled drug delivery vehicles for cancer treatment and their performance.

Although conventional chemotherapy has been successful to some extent, the main drawbacks of chemotherapy are its poor bioavailability, high-dose requirements, adverse side effects, low therapeutic indices, development of multiple drug resistance, and non-specific targeting. The main aim in the development of drug delivery vehicles is to successfully address these delivery-related problems and carry drugs to the desired sites of therapeutic action while reducing adverse side effects. In this review, we will discuss the different types of materials used as delivery vehicles for chemotherapeutic agents and their structural characteristics that improve the therapeutic efficacy of their drugs and will describe recent scientific advances in the area of chemotherapy, emphasizing challenges in cancer treatments.

Engineered Cellular Uptake and Controlled Drug Delivery Using Two Dimensional Nanoparticle and Polymer for Cancer Treatment.

Two major problems in chemotherapy, poor bioavailability of hydrophobic anticancer drug and its adverse side effects causing nausea, are taken into account by developing a sustained drug release vehicle along with enhanced bioavailability using two-dimensional layered double hydroxides (LDHs) with appropriate surface charge and its subsequent embedment in polymer matrix. A model hydrophobic anticancer drug, raloxifene hydrochloride (RH), is intercalated into a series of zinc iron LDHs with varying anion charge densities using an ion exchange technique. To achieve significant sustained delivery, drug-intercalated LDH is embedded in poly(ε-caprolactone) (PCL) matrix to develop intravenous administration and to improve the therapeutic index of the drug. The cause of sustained release is visualized from the strong interaction between LDH and drug, as measured through spectroscopic techniques, like X-ray photoelectron spectroscopy, infrared, UV-visible spectroscopy, and thermal measurement (depression of melting temperature and considerable reduction in heat of fusion), using differential scanning calorimeter, followed by delayed diffusion of drug from polymer matrix. Interestingly, polymer nanohybrid exhibits long-term and excellent in vitro antitumor efficacy as opposed to pure drug or drug-intercalated LDH or only drug embedded PCL (conventional drug delivery vehicle) as evident from cell viability and cell adhesion experiments prompting a model depicting greater killing efficiency (cellular uptake) of the delivery vehicle (polymer nanohybrid) controlled by its better cell adhesion as noticed through cellular uptake after tagging of fluorescence rhodamine B separately to drug and LDH. In vivo studies also confirm the sustained release of drug in the bloodstream of albino rats using polymer nanohybrid (novel drug delivery vehicle) along with a healthy liver vis-à-vis burst release using pure drug/drug-intercalated LDHs with considerable damaged liver.

A 'turn-on' fluorescent probe for lysosomal phosphatase: a comparative study for labeling of cancer cells.

We have described the ability of a newly synthesized fluorescent probe (LP1) to detect phosphatase activity in lysosomes in cancer cells. Probe LP1 displayed a 33-fold fluorescence intensity enhancement at λem 532 nm in the presence of phosphatase in HEPES buffer (pH 4.5). The quantum yield of probe LP1 was increased by ∼21-fold upon exposure to phosphatase at acidic pH. The probe LP1 is highly chemoselective toward phosphatase (ALP/ACP) and is insensitive to interference by ubiquitous biological analytes. The high cell adhesion property and cell viability of LP1 indicate that LP1 is biocompatible and nontoxic; these two characteristic features make it a suitable candidate for phosphatase tracking in living cells. LP1 dose-dependent fluorescence images in living cells suggested that the expression of phosphatase in cancer cells (HeLa) is 2-fold higher as compared to the normal NIH-3T3 cells. The colocalization images confirmed that LP1 was exclusively localized in lysosomes. We envision that LP1 could be a potential tool in clinical diagnosis for discriminating cancer cells from normal cells depending on the expression of phosphatase in lysosomes.

Layered double hydroxides as effective carrier for anticancer drugs and tailoring of release rate through interlayer anions.

Hydrophobic anticancer drug, raloxifene hydrochloride (RH) is intercalated into a series of magnesium aluminum layered double hydroxides (LDHs) with various charge density anions through ion exchange technique for controlled drug delivery. The particle nature of the LDH in presence of drug is determined through electron microscopy and surface morphology. The release of drug from the RH intercalated LDHs was made very fast or sustained by altering the exchangeable anions followed by the modified Freundlich and parabolic diffusion models. The drug release rate is explained from the interactions between the drug and LDHs along with order-disorder structure of drug intercalated LDHs. Nitrate bound LDH exhibits greater interaction with drug and sustained drug delivery against the loosely interacted phosphate bound LDH-drug, which shows fast release. Cell viability through MTT assay suggests drug intercalated LDHs as better drug delivery vehicle for cancer cell line against poor bioavailability of the pure drug. In vivo study with mice indicates the differential tumor healing which becomes fast for greater drug release system but the body weight index clearly hints at damaged organ in the case of fast release system. Histopathological experiment confirms the damaged liver of the mice treated either with pure drug or phosphate bound LDH-drug, fast release system, vis-à-vis normal liver cell morphology for sluggish drug release system with steady healing rate of tumor. These observations clearly demonstrate that nitrate bound LDH nanoparticle is a potential drug delivery vehicle for anticancer drugs without any side effect.

Biodegradable poly(ε-caprolactone) as a controlled drug delivery vehicle of vancomycin for the treatment of MRSA infection.

Biodegradable poly(ε-caprolactone) (PCL) is developed as a controlled drug delivery vehicle of vancomycin (VMC) with the advantage of avoiding a second surgery. The PCL-VMC hybrid, prepared through a solution route, is used as a delivery vehicle for vancomycin for controlling MRSA osteomyelitis as well as healing the cavity simultaneously in an experimental study. An in vitro study is conducted to optimize vancomycin impregnation in the PCL-VMC hybrid. An in vitro study on drug release from the hybrid material is investigated in phosphate buffer saline showing steady and sustained release of the drug. The release kinetics is fitted with several models and a non-Fickian nature is established following the Korsmeyer-Peppas model. Spectroscopic techniques and morphology observations reveal the cause of sustained release to be the strong interaction between the drug and the polymer. The results of the antibacterial assay show that the loading of vancomycin into the PCL matrix is able to maintain the activity of the pure drug. For the in vivo study, a unicortical defect is created in the metaphysis of the distal femur in rabbits. After contaminating the defect with MRSA, the 1st group of rabbits were treated with pure polymer, the 2nd group of rabbits were treated with normal saline (PBS), the 3rd group of rabbits were treated with pure VMC and in the last group of rabbits PCL-VMC was placed. Rabbits are assessed by clinical, radiological, histological, gross examination and bacterial load assays. Infection persisted throughout the period of study for both the pure polymer and PBS treated rabbits while rabbits treated with the PCL-VMC hybrid do not show any sign of infection. The VMC treated group rabbits show mild infection for the 1st week of the study; however, the infection becomes gradually more severe with time. Serial histology confirms the formation of new bone without any inflammation and necrosis for the rabbits treated with PCL-VMC. Importantly, the PCL-VMC hybrid bioadsorbs after delivery of the drug and thereby avoids the second surgery to remove the conventional implant.