Polymer-lipid hybrid nanoparticles (PLN) are an emerging nanocarrier platform made from building blocks of polymers and lipids. PLN integrate the advantages of biomimetic lipid-based nanoparticles (i.e. solid lipid nanoparticles and liposomes) and biocompatible polymeric nanoparticles. PLN are constructed from diverse polymers and lipids and their numerous combinations, which imparts PLN with great versatility for delivering drugs of various properties to their nanoscale targets. PLN can be classified into two types based on their hybrid nanoscopic structure and assembly methods: Type-I monolithic matrix and Type-II core-shell systems. This article reviews the history of PLN development, types of PLN, lipid and polymer candidates, fabrication methods, and unique properties of PLN. The applications of PLN in delivery of therapeutic or imaging agents alone or in combination for cancer treatment are summarized and illustrated with examples. Important considerations for the rational design of PLN for advanced nanoscale drug delivery are discussed, including selection of excipients, synthesis processes governing formulation parameters, optimization of nanoparticle properties, improvement of particle surface functionality to overcome macroscopic, microscopic and cellular biological barriers. Future directions and potential clinical translation of PLN are also suggested.

The development of strategies for isolating rare cells from complex matrices like blood is important for a wide variety of applications including the analysis of bloodborne cancer cells, infectious pathogens, and prenatal testing. Due to their high colloidal stability and surface-to-volume ratio, antibody-coated magnetic nanoparticles are excellent labels for cellular surface markers. Unfortunately, capture of nanoparticle-bound cells at practical flow rates is challenging due to the small volume, and thus low magnetic susceptibility, of magnetic nanoparticles. We have developed a means to capture nanoparticle-labeled cells using microstructures which create pockets of locally low linear velocity, termed velocity valleys. Cells that enter a velocity valley slow down momentarily, allowing the magnetic force to overcome the reduced drag force and trap the cells. Here, we describe a model for this mechanism of cell capture and use this model to guide the rational design of a device that efficiently captures rare cells and sorts them according to surface expression in complex matrices with greater than 10,000-fold specificity. By analysing the magnetic and drag forces on a cell, we calculate a threshold linear velocity for capture and relate this to the capture efficiency. We find that the addition of X-shaped microstructures enhances capture efficiency 5-fold compared to circular posts. By tuning the linear velocity, we capture cells with a 100-fold range of surface marker expression with near 100% efficiency and sort these cells into spatially distinct zones. By tuning the flow channel geometry, we reduce non-specific cell adhesion by 5-fold.

The poor intracellular uptake and non-specific binding of anticancer drugs into cancer cells are the bottlenecks in cancer therapy. Nanocarrier platforms provide the opportunities to improve the drug efficacy. Here we show a carbon-based nanomaterial nanodiamond (ND) that carried paclitaxel (PTX), a microtubule inhibitor, and cetuximab (Cet), a specific monoclonal antibody against epidermal growth factor receptor (EGFR), inducing mitotic catastrophe and tumor inhibition in human colorectal cancer (CRC). ND-PTX blocked the mitotic progression, chromosomal separation, and induced apoptosis in the CRC cells; however, NDs did not induce these effects. Conjugation of ND-PTX with Cet (ND-PTX-Cet) was specifically binding to the EGFR-positive CRC cells and enhanced the mitotic catastrophe and apoptosis induction. Besides, ND-PTX-Cet markedly decreased tumor size in the xenograft EGFR-expressed human CRC tumors of nude mice. Moreover, ND-PTX-Cet induced the mitotic marker protein phospho-histone 3 (Ser10) and apoptotic protein active-caspase 3 for mitotic catastrophe and apoptosis. Taken together, this study demonstrated that the co-delivery of PTX and Cet by ND enhanced the effects of mitotic catastrophe and apoptosis in vitro and in vivo, which may be applied in the human CRC therapy.

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Multidrug resistance (MDR) is a main cause of chemotherapy failure in cancer treatment. It is associated with complex cellular and molecular mechanisms including overexpression of drug efflux transporters, increased membrane rigidity, and impaired apoptosis. Numerous efforts have been made to overcome efflux transporter-mediated MDR using nanotechnology-based approaches. However, these approaches fail to surmount plasma membrane rigidity that attenuates drug penetration and nanoparticle endocytosis. Here, a "one-two punch" nanoparticle approach is proposed to coordinate intracellular biointeraction and bioreaction of a nanocarrier material docosahexaenoic acid (DHA) and an anticancer prodrug mitomycin C (MMC) to enhance mitochondrion-targeted toxicity. Incorporation of DHA in solid polymer-lipid nanoparticles first reduces the membrane rigidity in live cancer cells thereby increasing nanoparticle cellular uptake and MMC accumulation. Subsequent intracellular MMC bioreduction produces free radicals that in turn react with adjacent DHA inducing significantly elevated mitochondrial lipid peroxidation, leading to irreversible damage to mitochondria. Preferential tumor accumulation of the nanoparticles and the synergistic anticancer cytotoxicity remarkably inhibit tumor growth and prolonged host survival without any systemic toxicity in an orthotopic MDR breast tumor model. This work suggests that combinatorial use of biophysical and biochemical properties of nanocarrier materials with bioreactive prodrugs is a powerful approach to overcoming multifactorial MDR in cancer.

Finding effective disease‐modifying treatment for Alzheimer's disease remains challenging due to an array of factors contributing to the loss of neural function. The current study demonstrates a new strategy, using multitargeted bioactive nanoparticles to modify the brain microenvironment to achieve therapeutic benefits in a well‐characterized mouse model of Alzheimer's disease. The application of brain‐penetrating manganese dioxide nanoparticles significantly reduces hypoxia, neuroinflammation, and oxidative stress; ultimately reducing levels of amyloid β plaques within the neocortex. Analyses of molecular biomarkers and magnetic resonance imaging‐based functional studies indicate that these effects improve microvessel integrity, cerebral blood flow, and cerebral lymphatic clearance of amyloid β. These changes collectively shift the brain microenvironment toward conditions more favorable to continued neural function as demonstrated by improved cognitive function following treatment. Such multimodal disease‐modifying treatment may bridge critical gaps in the therapeutic treatment of neurodegenerative disease.

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BackgroundDeveloping effective disease‐modifying treatment for Alzheimer’s disease (AD) remains a tremendous challenge due to its multifactorial nature involving multiple pathologic signaling pathways in addition to ineffective drug delivery through the blood‐brain barrier (BBB).1 With this in mind our group has developed multifunctional bioreactive nanoparticles (Ab‐TP‐MDNPs), consisting of anti‐amyloid β antibody (Ab) linked to brain‐penetrating terpolymer (TP) and manganese dioxide (MnO2) nanoparticles (MDNPs), that are shown to reduce oxidative stress in AD brains.2 Given the early occurrence of oxidative stress, hypoxia, and vascular dysfunction in AD brains,3,4 we investigated the therapeutic effects of Ab‐TP‐MDNPs on reducing neuroinflammation and vascular dysfunction in an AD mouse model.MethodA transgenic mouse model of AD (TgCRND8 species) and wildtype littermates (WT) were treated with intravenous (i.v.) injection of Ab‐TP‐MDNPs (twice/week, 100 µmol Mn/kg b.w.) or vehicle for 2‐weeks. Oxidative and inflammatory biomarkers were examined using immunohistochemistry and enzyme‐linked immunosorbent assay (ELISA). Vascular function before and after the treatment was studied via high resolution magnetic resonance imaging (MRI). Cerebral blood flow (CBF) was assessed using FAIR (flow‐sensitive alternating inversion recovery) technique. BBB permeability was measured via T1 mapping re‐acquisition prior to and following i.v. injection of gadolinium‐diethylenetriamine penta‐acetate (Gd‐DTPA) at 1.2 mmol/kgResultAb‐TP‐MDNPs treatment significantly decreased inflammatory cytokines and activation of microglia and astrocytes markers (reactive microglia: hippocampus by 69% and cortex by 59%, reactive astrocytes: hippocampus by 32% and cortex by 33%). In addition, Ab‐TP‐MDNPs treatment improved CBF (cortex by 19% and subcortex by 35%) and vessel leakage by 29% in the cortex of AD mouse brains.ConclusionAb‐TP‐MDNPs treatment reduced neuroinflammation and vascular dysfunction in an AD mouse model. These findings suggest a new multimodal strategy for AD treatment and encourage further development of such approach for complex neurologic diseases.Reference:1. Panza F, Lozupone M, Logroscino G, Imbimbo BP. Nature Reviews Neurology. 2019;15(2):73‐88.2. He C, Ahmed T, Abbasi AZ, et al. Nano Today. 2020;35:100965.3. Sweeney MD, Montagne A, Sagare AP, et al. Alzheimer’s & Dementia. 2019;15(1):158‐167.4. Nortley R, Korte N, Izquierdo P, et al. Science. 2019:eaav9518.