Structure-Based Varieties of Polymeric Nanocarriers and Influences of Their Physicochemical Properties on Drug Delivery Profiles

Nanoliposome based biosensors for probing mycotoxins and their applications for food: A review

Mycotoxins are the most common feed and food contaminants affecting animals and humans, respectively; continuous exposure causes tremendous health problems such as kidney disorders, infertility, immune suppression, liver inflammation, and cancer. Consequently, their control and quantification in food materials is crucial. Biosensors are potential tools for the rapid detection and quantification of mycotoxins with high sensitivity and selectivity. Nanoliposomes (NLs) are vesicular carriers formed by self-assembling phospholipids that surround the aqueous cores. Utilizing their biocompatibility, biodegradability, and high carrying capacity, researchers have employed NLs in biosensors for monitoring various targets in biological and food samples. The NLs are used for surface modification, signal marker delivery, and detection of toxins, bacteria, pesticides, and diseases. Here, we review marker-entrapped NLs used in the development of NL-based biosensors for mycotoxins. These biosensors are sensitive, selective, portable, and cost-effective analytical tools, and the resulting signal can be produced and/or amplified with or without destroying the NLs. In addition, this review emphasizes the benefits of the immunoliposome method in comparison with traditional detection approaches. We expect this review to serve as a valuable reference for researchers in this rapidly growing field. The insights provided may facilitate the rational design of next-generation NL-based biosensors.

Acid-triggered in vivo aggregation of Janus nanoparticles for enhanced imaging-guided photothermal therapy

Poor tumor delivery efficiency remains a significant challenge for the integrated nanoplatform for diagnosis and treatment. Nanotherapeutics capable of aggregation in response to the tumor microenvironment has received considerable attention because of its ability to enhance tumor delivery efficiency and accumulation. We prepared smart Au-Fe3O4 Janus nanoparticles (GIJ NPs) modified with mixed-charged ligands (3,4-dihydroxyhydrocinnamic acid [DHCA] and trimethylammonium dopamine [TMAD]). The obtained GIJ@DHCA-TMAD could be stable at the pH of the blood and normal tissues, but aggregated into larger particles in response to the tumor acidic microenvironment, leading to greatly enhanced accumulation in cancer cells. The hydrodynamic diameters of GIJ@DHCA-TMAD increased from 28.2 to 105.7 nm when the pH decreased from 7.4 to 5.5. Meanwhile, the T 2 magnetic resonance imaging (MRI) contrast capability, photoacoustic imaging (PAI) performance, and photothermal conversion efficiency of GIJ@DHCA-TMAD were also enhanced with increasing diameter. Tumor-specific enhanced MRI and PAI can precisely locate tumor boundaries and can be used to perform preliminary photothermal tumor ablation therapy: the pH-sensitive GIJ@DHCA-TMAD can be used in dual-mode, tumor-specific imaging-guided photothermal therapy to better meet the multiple requirements for in vivo applications.

Encapsulation Reduces the Deleterious Effects of Salicylic Acid Treatments on Root Growth and Gravitropic Response

The role of salicylic acid (SA) on plant responses to biotic and abiotic stresses is well documented. However, the mechanism by which exogenous SA protects plants and its interactions with other phytohormones remains elusive. SA effect, both free and encapsulated (using silica and chitosan capsules), on Arabidopsis thaliana development was studied. The effect of SA on roots and rosettes was analysed, determining plant morphological characteristics and hormone endogenous levels. Free SA treatment affected length, growth rate, gravitropic response of roots and rosette size in a dose-dependent manner. This damage was due to the increase of root endogenous SA concentration that led to a reduction in auxin levels. The encapsulation process reduced the deleterious effects of free SA on root and rosette growth and in the gravitropic response. Encapsulation allowed for a controlled release of the SA, reducing the amount of hormone available and the uptake by the plant, mitigating the deleterious effects of the free SA treatment. Although both capsules are suitable as SA carrier matrices, slightly better results were found with chitosan. Encapsulation appears as an attractive technology to deliver phytohormones when crops are cultivated under adverse conditions. Moreover, it can be a good tool to perform basic experiments on phytohormone interactions.

Nanocarrier-based delivery of arsenic trioxide for hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) poses a severe threat to human health and economic development. Despite many attempts at HCC treatment, most are inevitably affected by the genetic instability and variability of tumor cells. Arsenic trioxide (ATO) has shown to be effective in HCC. However, time-consuming challenges, especially the optimal concentration in tumor tissue and bioavailability of ATO, remain to be overcome for its transition from the bench to the bedside. To bypass these issues, nanotechnology-based delivery systems have been developed for prevention, diagnosis, monitoring and treatment in recent years. This article is a systematic overview of the latest contributions and detailed insights into ATO-loaded nanocarriers, with particular attention paid to strategies for improving the efficacy of nanocarriers of ATO.

Chitosan/Lactic Acid Systems: Liquid Crystalline Behavior, Rheological Properties, and Riboflavin Release In Vitro

Chitosan or its derivatives exhibit lyotropic liquid crystalline mesophases under certain conditions due to its semi-rigid structures. This work describes the development of chitosan-based biocompatible systems that include new components: lactic acid and non-ionic surfactants. Polarized optical microscopy studies revealed that these systems are capable of forming gels or lyotropic liquid crystals (LLCs) in a certain range of chitosan and lactic acid concentrations. According to the viscosity studies, the rheological flow of the LLCs can be accurately described by the Casson flow model. The intermolecular interactions of the LLC components were studied by FTIR spectroscopy. According to the FTIR data, hydrogen bonding is supposed to be responsible for the formation of the LLCs. In the studied systems, this LLC complex exists as the [ChitH+·CH3-CH(OH)-COO-] ion pair. The studied gel and LLCs were shown to possess the most prolonged release capabilities for riboflavin among similar binary LLC systems. The supramolecular organization and rheological characteristics of the studied chitosan-based systems were found to affect the release of riboflavin.

Thermo-Sensitive Poly (N-isopropylacrylamide-co-polyacrylamide) Hydrogel for pH-Responsive Therapeutic Delivery

Stimuli-response polymeric nanoparticles have emerged as a carrier system for various types of therapeutic delivery. In this study, we prepared a dual pH- and thermo-sensitive copolymer hydrogel (HG) system (PNIPAm-co-PAAm HG), using N-isopropyl acrylamide (NIPAm) and acrylamide (AAm) as comonomers. The synthesized PNIPAm-co-PAAm HG was characterized using various instrumental characterizations. Moreover, the PNIPAm-co-PAAm HG's thermoresponsive phase transition behavior was investigated, and the results showed that the prepared HG responds to temperature changes. In vitro drug loading and release behavior of PNIPAm-co-PAAm HG was investigated using Curcumin (Cur) as the model cargo under different pH and temperature conditions. The PNIPAm-co-PAAm HG showed pH and temperature-responsive drug release behavior and demonstrated about 65% Cur loading efficiency. A nearly complete release of the loaded Cur occurred from the PNIPAm-co-PAAm HG over 4 h at pH 5.5 and 40 °C. The cytotoxicity study was performed on a liver cancer cell line (HepG2 cells), which revealed that the prepared PNIPAm-co-PAAm HG showed good biocompatibility, suggesting that it could be applied as a drug delivery carrier. Moreover, the in vitro cytocompatibility test (MTT assay) results revealed that the PNIPAm-co-PAAm HG is biocompatible. Therefore, the PNIPAm-co-PAAm HG has the potential to be useful in the delivery of drugs in solid tumor-targeted therapy.

Natural Products-Based Nanoformulations: A New Approach Targeting CSCs to Cancer Therapy

Cancer stem cells (CSCs) lead to the occurrence and progression of cancer due to their strong tumorigenic, self-renewal, and multidirectional differentiation abilities. Existing cancer treatment methods cannot effectively kill or inhibit CSCs but instead enrich them and produce stronger proliferation, invasion, and metastasis capabilities, resulting in cancer recurrence and treatment resistance, which has become a difficult problem in clinical treatment. Therefore, targeting CSCs may be the most promising approach for comprehensive cancer therapy in the future. A variety of natural products (NP) have significant antitumor effects and have been identified to target and inhibit CSCs. However, pharmacokinetic defects and off-target effects have greatly hindered their clinical translation. NP-based nanoformulations (NPNs) have tremendous potential to overcome the disadvantages of NP against CSCs through site-specific delivery and by improving their pharmacokinetic parameters. In this review, we summarize the recent progress of NPNs targeting CSCs in cancer therapy, looking forward to transforming preclinical research results into clinical applications and bringing new prospects for cancer treatment.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

Polymeric Nanoreactors with Chemically Tunable Redox Responsivity

Bioresponsive nanomaterials are increasingly important in a variety of applications such as disease imaging, drug delivery, and tissue engineering. However, it remains a big challenge to manipulate response efficacy of such materials for performance optimization in a highly complex milieu in vivo. Here, we developed chemically adjustable nanoreactors (CANs) with the structure of polymeric cores and albumin shells to achieve tunable redox responsivity. In vitro characterization demonstrates stable, spherical nanoparticles of the CANs with a particle size of about 50 nm. The fluorescence activation ratios of the CANs are determined by various albumin modification densities on the shell. Meanwhile, the response sensitivity of the CANs to GSH levels (0.6-4 mM) can be tuned by acid-base properties of polymeric blocks in the core. This unique tunable redox responsivity enables the CANs suitable for probe optimization in cancer imaging both in vivo and at histological levels. Overall, this study offers a new design strategy for manipulation on performance of core/shell nanoreactors or bioresponsive nanomaterials.

Insights on Development Aspects of Polymeric Nanocarriers: The Translation from Bench to Clinic

Scientists are focusing immense attention on polymeric nanocarriers as a prominent delivery vehicle for several biomedical applications including diagnosis of diseases, delivery of therapeutic agents, peptides, proteins, genes, siRNA, and vaccines due to their exciting physicochemical characteristics which circumvent degradation of unstable drugs, reduce toxic side effects through controlled release, and improve bioavailability. Polymers-based nanocarriers offer numerous benefits for in vivo drug delivery such as biocompatibility, biodegradability, non-immunogenicity, active drug targeting via surface modification, and controlled release due to their pH-and thermosensitive characteristics. Despite their potential for medicinal use, regulatory approval has been achieved for just a few. In this review, we discuss the historical development of polymers starting from their initial design to their evolution as nanocarriers for therapeutic delivery of drugs, peptides, and genes. The review article also expresses the applications of polymeric nanocarriers in the pharmaceutical and medical industry with a special emphasis on oral, ocular, parenteral, and topical application of drugs, peptides, and genes over the last two decades. The review further examines the practical, regulatory, and clinical considerations of the polymeric nanocarriers, their safety issues, and directinos for future research.

Intrinsically Disordered Protein Micelles as Vehicles for Convection-Enhanced Drug Delivery to Glioblastoma Multiforme

Lipid and micelle-based nanocarriers have been explored for anticancer drug delivery to improve accumulation and uptake in tumor tissue. As an experimental opportunity in this area, our lab has developed a protein-based micelle nanocarrier consisting of a hydrophilic intrinsically disordered protein (IDP) domain bound to a hydrophobic tail, termed IDP-2Yx2A. This construct can be used to encapsulate hydrophobic chemotherapeutics that would otherwise be too insoluble in water to be administered. In this study, we evaluate the in vivo efficacy of IDP-2Yx2A by delivering a highly potent but water-insoluble cancer drug, SN38, into glioblastoma multiforme (GBM) tumors via convection-enhanced delivery (CED). The protein carriers alone are shown to elicit minimal toxicity effects in mice; furthermore, they can encapsulate and deliver concentrations of SN38 that would otherwise be lethal without the carriers. CED administration of these drug-loaded micelles into mice bearing U251-MG GBM xenografts resulted in slowed tumor growth and significant increases in median survival times compared to nonencapsulated SN38 and PBS controls.

Intrinsically Bioactive Manganese-Eumelanin Nanocomposites Mediated Antioxidation and Anti-Neuroinflammation for Targeted Theranostics of Traumatic Brain Injury

Overproduced reactive oxygen species and the induced oxidative stress and neuroinflammation often result in secondary injury, which is associated with unfavorable prognosis in traumatic brain injury (TBI). Unfortunately, current medications cannot effectively ameliorate the secondary injury at traumatic sites. Here, it is reported that intrinsically bioactive multifunctional nanocomposites (ANG-MnEMNPs-Cur, AMEC) mediate antioxidation and anti-neuroinflammation for targeted TBI theranostics, which are engineered by loading the neuroprotective agent curcumin on angiopep-2 functionalized and manganese doped eumelanin-like nanoparticles. After intravenous delivery, efficient AMEC accumulation is observed in lesions of TBI mice models established by controlled cortical impact method, evidenced by T₁ -T₂ magnetic resonance and photoacoustic dual-modal imaging. Therapeutically, AMEC effectively alleviates neuroinflammation, protects blood-brain barrier integrity, relieves brain edema, reduces brain tissue loss, and improves the cognition of TBI mice. Mechanistically, following the penetration into the traumatic tissues via angiopep-2 mediated targeting effect, the efficacy of AMEC is synergistically improved by combined functional moieties of curcumin and eumelanin. This is achieved by the alleviation of oxidative stress, inhibition of neuroinflammation via M1-to-M2 macrophage reprogramming, and promotion of neuronal regeneration. The as-developed AMEC with well-defined mechanisms of action may represent a promising targeted theranostics strategy for TBI and other neuroinflammation-associated intracranial diseases.

Rosmarinic Acid-Loaded Polymeric Nanoparticles Prepared by Low-Energy Nano-Emulsion Templating: Formulation, Biophysical Characterization, and In Vitro Studies

Rosmarinic acid (RA), a caffeic acid derivative, has been loaded in polymeric nanoparticles made up of poly(lactic-co-glycolic acid) (PLGA) through a nano-emulsion templating process using the phase-inversion composition (PIC) method at room temperature. The obtained RA-loaded nanoparticles (NPs) were colloidally stable exhibiting average diameters in the range of 70–100 nm. RA was entrapped within the PLGA polymeric network with high encapsulation efficiencies and nanoparticles were able to release RA in a rate-controlled manner. A first-order equation model fitted our experimental data and confirmed the prevalence of diffusion mechanisms. Protein corona formation on the surface of NPs was assessed upon incubation with serum proteins. Protein adsorption induced an increase in the hydrodynamic diameter and a slight shift towards more negative surface charges of the NPs. The radical scavenging activity of RA-loaded NPs was also studied using the DPPH·assay and showed a dose–response relationship between the NPs concentration and DPPH inhibition. Finally, RA-loaded NPs did not affect the cellular proliferation of the human neuroblastoma SH-SY5Y cell line and promoted efficient cellular uptake. These results are promising for expanding the use of O/W nano-emulsions in biomedical applications.

Influence of Molecular Structures on Fluorescence of Flavonoids and Their Detection in Mammalian Cells

Flavonoids are being increasingly applied for the treatment of various diseases due to their anti-cancer, anti-oxidant, anti-inflammatory, and anti-viral properties. However, it is often challenging to detect their presence in cells and tissues through bioimaging, as most of them are not fluorescent or are too weak to visualize. Here, fluorescence possibilities of nine naturally occurring analogous flavonoids have been investigated through UV/visible spectroscopy, molecular structure examination, fluorescent images in mammalian cells and their statistical analysis employing aluminum chloride and diphenylboric acid 2-aminoethyl ester as fluorescence enhancers. It is found that, in order to form a stable fluorescent complex with an enhancer, flavonoids should have a keto group at C4 position and at least one -OH group at C3 or C5 position. Additionally, the presence of a double bond at C2–C3 can stabilize extended quinonoid structure at the cinnamoyl moiety, which thereby enhances the complex stability. A possible restriction to the free rotation of ring B around C1′–C2 single bond can contribute to the further enhancement of fluorescence. Thus, these findings can act as a guide for distinguishing flavonoids capable of exhibiting fluorescence from thousands of their analogues. Finally, using this technique, flavonoids are detected in neuroblastoma cells and their time course assay is conducted via fluorescence imaging. Their cellular uptake efficiency is found to be high and differential in nature and their distribution throughout the cytoplasm is clearly detected.

pH-responsive polyelectrolyte complexation on upconversion nanoparticles: a multifunctional nanocarrier for protection, delivery, and 3D-imaging of therapeutic protein

The delicate tertiary structure of proteins, their susceptibility to heat- and enzyme-induced irreversible denaturation, and their tendency to get accumulated at the cell membrane during uptake are daunting challenges in proteinaceous therapeutic delivery. Herein, a polyelectrolyte complex having encapsulated therapeutic protein has been designed on the surface of upconverting luminescent nanoparticles (NaYF₄:20%Yb³⁺,2%Er³⁺). This nanosized complex system has been found to overcome the challenges of protein aggregation at the cell membrane. It has also defended the cargo from denaturation against (a) enzymatic action of proteinase K and (b) heat (up to 60 °C). Additionally, the nanoparticles at the core of the loaded carrier served as near-infrared (980 nm) responsive probe to accomplish extended-duration 3D imaging during protein delivery. The outer layer of polymer played pivotal role to protect/retrieve the protein structure from denaturation as investigated by circular dichroism studies. Both the masked surface-charges of protein and the nanoscale size of the loaded carrier have facilitated their efficient passage through the cell membrane as observed through 3D images/videos. This nanocarrier is the first of its kind for direct delivery of protein. Thus, the findings can be useful to protect and transport various proteinaceous materials to overcome challenges of accumulation at the cell-membrane and low-temperature storage, as nature does.

Modulating the reactivity of polymer with pendant ester groups by methylation reaction for preparing functional polymers

Chemical reaction triggered the reactivity of polymeric esters.