In Vitro Biocompatibility of Surface-Modified Porous Alumina Particles for HepG2 Tumor Cells: Toward Early Diagnosis and Targeted Treatment

Mesoporous Fe3O4/SiO2/poly(2-carboxyethyl acrylate) composite polymer particles for pH-responsive loading and targeted release of bioactive molecules

pH-responsive polymer microspheres undergoing reversible changes in their surface properties have been proved useful for drug delivery to targeted sites. This paper is aimed at preparing pH-responsive polymer-modified magnetic mesoporous SiO2 particles. First, mesoporous magnetic (Fe3O4) core-particles are prepared using a one-pot solvothermal method. Then, magnetic Fe3O4 particles are covered with a C[double bond, length as m-dash]C functional mesoporous SiO2 layer before seeded emulsion polymerization of 2-carboxyethyl acrylate (2-CEA). The composite polymer particles are named Fe3O4/SiO2/P(2-CEA). The average diameters of the Fe3O4 core and Fe3O4/SiO2/P(2-CEA) composite polymer particles are 414 and 595 nm, respectively. The mesoporous (pore diameter = 3.41 nm) structure of Fe3O4/SiO2/P(2-CEA) composite polymer particles is confirmed from Brunauer-Emmett-Teller (BET) surface analysis. The synthesized Fe3O4/SiO2/P(2-CEA) composite polymer exhibited pH-dependent changes in volume and surface charge density due to deprotonation of the carboxyl group under alkaline pH conditions. The change in the surface properties of Fe3O4/SiO2/P(2-CEA) composite polymer particles following pH change is confirmed from the pH-dependent sorption of cationic methylene blue (MB) and anionic methyl orange (MO) dye molecules. The opening of the pH-responsive P(2-CEA) gate valve at pH 10.0 allowed the release of loaded vancomycin up to 99% after 165 min and p-acetamido phenol (p-AP) up to 46% after 225 min. Comparatively, the amount of release is lower at pH 8.0 but still suitable for drug delivery applications. These results suggested that the mesoporous Fe3O4/SiO2 composite seed acted as a microcapsule, while P(2-CEA) functioned as a gate valve across the porous channel. The prepared composite polymer can therefore be useful for treating intestine/colon cancer, where the pH is comparatively alkaline.

Electrochemical biosensing based on folic acid-triazine-grafted reduced graphene oxide: a highly selective breast cancer cell sensor

Based on the results of this research, a new electrochemical sensor has been developed to detect human breast cancer cells (MCF-7). A folic acid (FA)-functionalized triazine-grafted reduced graphene oxide (RGOTrz) was used as the modifier of a glassy carbon electrode (GCE) for application as the sensing element. The composition of the resulting FA-RGOTrz/GCE was investigated using XRD (X-ray diffraction), FT-IR (Fourier-transform infrared) spectroscopy, SEM (scanning electron microscopy) and UV-vis spectroscopy studies. CV (cyclic voltammetry) and EIS (electrochemical impedance spectroscopy) techniques were also used to characterize the electrochemical proficiency of the new electrode. Further, MCF-7 cancer cells were examined in solutions of phosphate buffer and [Fe(CN)6]3-/4- as a suitable supporting electrolyte and a useful probe, respectively. The FA-RGOTrz/GCE provides a suitable substrate to reversible redox reactions and provides good electrochemical signals after binding to cancer cells. DPV (differential pulse voltammetry) results indicated that the binding of folate receptor (FR) in the MCF-7 cell to the RGOTrz-modified electrode, in the presence of [Fe(CN)6]3-/4-, reduced folic acid, diminished electron transfer and collapsed the current signal. During the measured flow, a detection limit of 50 human breast cancer cells per milliliter was obtained. The FA-RGOTrz/GCE, with its unique structural design, significantly increases the electron transfer and electrochemical activity towards the detection of MCF-7 cells. This FA-RGOTrz/GCE sensor, due to its special structure, shows high sensitivity to FR in MCF-7 cells and excellent, reliable and satisfactory performance and a great promise for use in industries and medical field.

Characteristic Synthesis of a Covalent Organic Framework and Its Application in Multifunctional Tumor Therapy

For decades, covalent organic frameworks (COFs) have attracted wide biomedical interest due to their unique properties including ease of synthesis, porosity, and adjustable biocompatibility. Versatile COFs can easily encapsulate various therapeutic drugs due to their extremely high payload and porosity. COFs with abundant functional groups can be surface-modified to achieve active targeting and enhance biocompatibility. In this paper, the latest developments of COFs in the biomedical field are summarized. First, the classification and synthesis of COFs are discussed. Cancer diagnosis and treatment based on COFs are studied, and the advantages and limitations of each method are discussed. Second, the specific preparation methods to obtain specific therapeutic properties are summarized. Finally, based on the combination and modification of COFs with various components, this review system summarizes different combination therapies. In addition, the main challenges faced in COF research and prospects for applying COFs to cancer diagnosis and treatment are evaluated. This review provides enlightening insights into the interdisciplinary research on COFs and applications in biomedicine, which highlight the great expectations for their further clinical transformation.

Recent advances in bionanomaterials for liver cancer diagnosis and treatment

According to the World Health Organization, liver cancer is the fourth leading cause of cancer associated with death worldwide. It demands effective treatment and diagnostic strategies to hinder its recurrence, complexities, aggressive metastasis and late diagnosis. With recent progress in nanotechnology, several nanoparticle-based diagnostic and therapeutic modalities have entered into clinical trials. With further developments in nanoparticle mediated liver cancer diagnosis and treatment, the approach holds promise for improved clinical liver cancer management. In this review, we discuss the key advances in nanoparticles that have potential for liver cancer diagnosis and treatment. We also discuss the potential of nanoparticles to overcome the limitations of existing therapeutic modalities.

Recent Advances in Nanoporous Anodic Alumina: Principles, Engineering, and Applications

The development of aluminum anodization technology features many stages. With the story stretching for almost a century, rather straightforward-from current perspective-technology, raised into an iconic nanofabrication technique. The intrinsic properties of alumina porous structures constitute the vast utility in distinct fields. Nanoporous anodic alumina can be a starting point for: Templates, photonic structures, membranes, drug delivery platforms or nanoparticles, and more. Current state of the art would not be possible without decades of consecutive findings, during which, step by step, the technique was more understood. This review aims at providing an update regarding recent discoveries-improvements in the fabrication technology, a deeper understanding of the process, and a practical application of the material-providing a narrative supported with a proper background.

Effect of concentration of PEG coated gold nanoparticle on lung surfactant studied with coarse-grained molecular dynamics simulations

The surface modification of nanoparticles can not only change the physical and chemical properties of particles, such as the hydrophilic and hydrophobic properties and surface charges of nanoparticles to a certain extent, but also bring new functions to nanoparticles, such as membrane permeability and targeting. Inhaled nanoparticles (NPs) are experienced by the first biological barrier inside the alveolus known as lung surfactant (LS), consisting of phospholipids and proteins in the form of the monolayer at the air-water interface. Inhaled NPs can reach deep into the lungs and interfere with the biophysical properties of the lung components. The interaction mechanisms of bare gold nanoparticles (AuNPs) with the LS monolayer are not well understood. Coarse-grained molecular dynamics simulations were carried out to have a study on the interactions of PEG coated AuNPs with LS monolayers. It was observed that the interactions of AuNPs and LS components make the monolayer structure deform and change the biophysical properties of LS monolayer. The results also indicate that AuNPs with high concentrations hinder the lowering of the LS surface tension and reduce lateral mobility of lipids. Overall, the simulation results can provide guidance for the design of ligand protected NPs as drug carriers and can identify the nanoparticles potential side effect on lung surfactant.

Vertical Flow Assay for Inflammatory Biomarkers Based on Nanofluidic Channel Array and SERS Nanotags

There is a great demand for the development of detection assays for inflammation infection diagnosis with high throughput and ultrasensitivity. Herein, a vertical flow assay system with functionalized nanoporous anodic aluminum oxide (AAO) as sensing membrane, and encoded core-shell surface enhanced Raman scattering (SERS) nanotags as labels for multiple inflammatory biomarkers detection is presented. A 2 × 2 test array on the porous AAO is developed and modified with multiple capture antibodies to capture inflammatory biomarkers from samples. Due to the high surface area to volume ratio of the AAO membrane, and its influence on plasmonic coupling, the electromagnetic field of the encoded core-shell SERS nanotags is enhanced. Detection limits of 53.4, 4.72, 48.3, and 7.53 fg mL^-1 are realized for C reactive protein, interleukin-6, serum amyloid A, and procalcitonin, respectively, with a linear dynamic range spanning at least five orders of magnitude. In addition, the proposed method also shows acceptable accuracy and repeatability for the detection of clinical samples. Therefore, this approach is expected to be a powerful point of care testing tool for disease diagnosis in facility limited areas.

A dual-step immobilization/imprinting approach to prepare magnetic molecular imprinted polymers for selective removal of human serum albumin

One viable solution to improve the conformational stability of template proteins is to use multiple, weaker modes of action to immobilize proteins on the surfaces of a solid support. Herein, we introduce a novel surface imprinting technique for human serum albumin (HSA) by a dual immobilization/imprinting strategy. Specifically, HSA was first conjugated to the surfaces of magnetic Fe₃O₄ nanoparticles through a reversible aldmine condensation reaction. Dopamine (DA) was then used to imprint the protein template via an auto-polymerization reaction in biocompatible aqueous media. The resultant magnetic molecular imprinted polymers (MMIPs) possess high adsorption capacity (70.2 mg g^-1), superior selectivity (IF = 4.54), and rapid capturing kinetics to HSA (within 20 min). We successfully demonstrate the practical applicability of MMIPs to the selective removal of HSA from human serum sample. Our work offers a novel and robust solution to develop proteins imprinted materials with high binding capacity and selectivity. We anticipate such materials will find wide applications to protein detection or removal in diverse real-life clinical and biological samples.

Aptamer-Based Nanoporous Anodic Alumina Interferometric Biosensor for Real-Time Thrombin Detection

Aptamer biosensors are one of the most powerful techniques in biosensing. Achieving the best platform to use in aptamer biosensors typically includes crucial chemical modifications that enable aptamer immobilization on the surface in the most efficient manner. These chemical modifications must be well defined. In this work we propose nanoporous anodic alumina (NAA) chemically modified with streptavidin as a platform for aptamer immobilization. The immobilization of biotinylated thrombin binding aptamer (TBA) was monitored in real time by means of reflective interferometric spectroscopy (RIfS). The study has permitted to characterize in real time the path to immobilize TBA on the inner pore walls of NAA. Furthermore, this study provides an accurate label-free method to detect thrombin in real-time with high affinity and specificity.

Selective and Sensitive Probe Based in Oligonucleotide-Capped Nanoporous Alumina for the Rapid Screening of Infection Produced by Candida albicans

A robust, sensitive, and time-competitive system to detect Candida albicans in less than 30 min in clinical samples based in capped nanoporous anodic alumina (NAA) is developed. In the proposed design, NAA pores are loaded with rhodamine B and then blocked with an oligonucleotide that is able to recognize C. albicans DNA. The capped material shows negligible cargo release, whereas dye delivery is selectively accomplished when genomic DNA from C. albicans is present. This procedure has been successfully applied to detect C. albicans in clinical samples from patients infected with this yeast. When compared with classical C. albicans detection methods, the proposed probe has a short assay time, high sensitivity and selectivity, demonstrating the high potential of this simple design for the diagnosis of infection produced by C. albicans.

Targeted Delivery of Paclitaxel in Liver Cancer Using Hyaluronic Acid Functionalized Mesoporous Hollow Alumina Nanoparticles

Hyaluronic acid functionalized mesoporous hollow alumina nanoparticles (HMHA) were used as a tumor-targeted delivery carrier for liver cancer therapy. Paclitaxel (PAC) incorporated in the carrier by the adsorption method was analyzed by X-ray diffraction and differential scanning calorimetry. PAC was found to be in an amorphous state. The hyaluronic acid coated on the surface of mesoporous hollow alumina nanoparticles (MHA) regulated the drug release rate and the loaded samples obtained a sustained drug release. In vitro experiments demonstrated that paclitaxel-hyaluronic acid functionalized mesoporous hollow alumina nanoparticles (PAC-HMHA) had a high cellular uptake, which increased the drug level in tumor tissues and was beneficial to promote apoptosis. An in vivo tumor inhibition rate study demonstrated that PAC-HMHA (64.633 ± 4.389%) had a better antitumor effect than that of paclitaxel-mesoporous alumina nanoparticles (PAC-MHA, 56.019 ± 6.207%) and pure PAC (25.593 ± 4.115%). Therefore it can be concluded that PAC-HMHA are a prospective tumor-targeted delivery medium and can be useful for future cancer therapy.

3D Nanoporous Anodic Alumina Structures for Sustained Drug Release

The use of nanoporous anodic alumina (NAA) for the development of drug delivery systems has gained much attention in recent years. The release of drugs loaded inside NAA pores is complex and depends on the morphology of the pores. In this study, NAA, with different three-dimensional (3D) pore structures (cylindrical pores with several pore diameters, multilayered nanofunnels, and multilayered inverted funnels) were fabricated, and their respective drug delivery rates were studied and modeled using doxorubicin as a model drug. The obtained results reveal optimal modeling of all 3D pore structures, differentiating two drug release stages. Thus, an initial short-term and a sustained long-term release were successfully modeled by the Higuchi and the Korsmeyer-Peppas equations, respectively. This study demonstrates the influence of pore geometries on drug release rates, and further presents a sustained long-term drug release that exceeds 60 days without an undesired initial burst.

In vivo toxicological assessment of electrochemically engineered anodic alumina nanotubes: a study of biodistribution, subcutaneous implantation and intravenous injection

Electrochemically engineered anodic alumina nanotubes (AANTs) have recently shown good in vitro biocompatibility. However, in vivo toxicological and pathological studies are required to clarify the bio-safety of this novel nanomaterial. Herein, we present a pioneering pilot toxicity study on AANTs in immune-competent murine models (Balb/c mice, 8 weeks). AANTs were administered by intravenous (IV) injection and subcutaneous (SC) implantation routes considering the future toxicological implications associated with this nanomaterial for potential biomedical applications. AANTs, 736 nm long and 90 nm in outer diameter, were chosen as a nanomaterial model. We demonstrate that IV injected AANTs do not have any effect on the mortality or body weight of these animal models within 28 days at three different doses (20, 50, 100 mg kg^-1). The biodistribution of AANTs characterized by fluorescence imaging and inductively coupled plasma revealed the accumulation of AANTs in the liver and spleen after IV injection. When AANTs were injected intravenously, the highest dose of 100 mg kg^-1 caused moderate hepatotoxicity, identified by histopathological analysis. The implantation of AANTs subcutaneously and directly under the skin leads to an inflammatory response, which is a typical foreign body reaction. Taken together, this work provides new insights into the toxicity patterns of new nanomaterials such as AANTs and establishes a rationale for the design of functional AANTs for future biomedical applications.

Synthesis and potential applications of silver-porous aluminium oxide nanocomposites as prospective antiseptics and bactericides

Alumina micro-spheres with mesoporous structure called porous aluminium oxide (POA) were prepared through a hydrothermal method using Al₂(SO₄)₃·18H₂O followed by a thermal decomposition process. Silver nanocomposites of POA (Ag/POAs) with high biochemical activity were synthesized by sorption of silver nanoparticles in the matrix of POA. Synthesis of Ag/POAs using photochemical reduction enables the producing silver nanoparticles preventing their aggregation. Ag/POAs demonstrated a stronger bactericidal activity than POA. The colony-forming ability of Escherichia coli was completely lost in 1 day on Ag/POAs at silver nanoparticles concentration of 0.241 ppm. Staphylococcus epidermidis displayed higher tolerance to Ag/POAs at all silver nanoparticles concentrations, the growth of Staphylococcus epidermidis was stopped at concentration of 0.374 ppm. The bactericidal activity of Ag/POAs against bacteria in drinking water was found to be highly effective, the growth of bacteria was completely lost in 1 day at silver nanoparticles concentration of 0.108 ppm.

Sustained, Controlled and Stimuli-Responsive Drug Release Systems Based on Nanoporous Anodic Alumina with Layer-by-Layer Polyelectrolyte

Controlled drug delivery systems are an encouraging solution to some drug disadvantages such as reduced solubility, deprived biodistribution, tissue damage, fast breakdown of the drug, cytotoxicity, or side effects. Self-ordered nanoporous anodic alumina is an auspicious material for drug delivery due to its biocompatibility, stability, and controllable pore geometry. Its use in drug delivery applications has been explored in several fields, including therapeutic devices for bone and dental tissue engineering, coronary stent implants, and carriers for transplanted cells. In this work, we have created and analyzed a stimuli-responsive drug delivery system based on layer-by-layer pH-responsive polyelectrolyte and nanoporous anodic alumina. The results demonstrate that it is possible to control the drug release using a polyelectrolyte multilayer coating that will act as a gate.