Prussian blue nanoparticle-based pH-responsive self-assembly for enhanced photothermal and chemotherapy of tumors.

In recent years, there has been growing interest in size-transformable nanoplatforms that exhibit active responses to acidic microenvironments, presenting promising prospects in the field of nanomedicine for tumor therapy. However, the design and fabrication of such size-adjustable nanotherapeutics pose significant challenges compared to size-fixed nanocomposites, primarily due to their distinct pH-responsive requirements. In this study, we developed pH-activated-aggregating nanosystems to integrate chemotherapy and photothermal therapy by creating size-transformable nanoparticles based on Prussian blue nanoparticles (PB NPs) anchored with acid-responsive polyoxometalates (POMs) quantum dots via electrostatic interactions (PPP NPs). Subsequently, we utilized doxorubicin (DOX) as a representative drug to formulate PPPD NPs. Notably, PPPD NPs exhibited a significant response to acidic conditions, resulting in changes in surface charge and rapid aggregation of PPP NPs. Furthermore, the aggregated PPP NPs demonstrated excellent photothermal properties under near-infrared laser irradiation. Importantly, PPPD NPs prolonged their retention time in tumor cells via a size-transformation approach. In vitro cellular assays revealed that the anticancer efficacy of PPPD NPs was significantly enhanced. The IC50 values for the PPPD NPs groupand the PPPD NPs + NIR group were 50.11 µg/mL and 30.9 µg/mL. Overall, this study introduces a novel strategy for cancer therapy by developing size-aggregating nano-drugs with stimuli-responsive properties, holding promise for improved therapeutic outcomes in future combination approaches involving photothermal therapy and chemotherapy.

Biomedical applications of magnetosomes: State of the art and perspectives.

Magnetosomes, synthesized by magnetotactic bacteria (MTB), have been used in nano- and biotechnological applications, owing to their unique properties such as superparamagnetism, uniform size distribution, excellent bioavailability, and easily modifiable functional groups. In this review, we first discuss the mechanisms of magnetosome formation and describe various modification methods. Subsequently, we focus on presenting the biomedical advancements of bacterial magnetosomes in biomedical imaging, drug delivery, anticancer therapy, biosensor. Finally, we discuss future applications and challenges. This review summarizes the application of magnetosomes in the biomedical field, highlighting the latest advancements and exploring the future development of magnetosomes.

3D cell culture based on artificial cells and hydrogel under microgravity for bottom-up microtissue constructs.

The use of hydrogel as a filling medium to recombine dispersed microencapsulated cells to form an embedded gel-cell microcapsule complex is a new idea based on bottom-up tissue construction, which is benefit for cell distribution and of great significance for tissue construction research in vitro. In this experiment, sodium alginate and chitosan were used as the main materials, rat normal liver cell BRL-3A was used as the model cell to prepare "artificial cells". Silkworm pupa was used as raw material to extract silk fibroin solution, which was prepared by ultrasound to be the silk fibroin gel; silk fibroin hydrogel-microencapsulated hepatocyte embedded complex was then prepared by using silk fibroin gel as filling medium; the complex was cultured under three modes (static, shaking, and 3D microgravity), and the tissue forming ability of rat hepatocytes was investigated. The results showed that the microgravity culture condition can enhance the cell proliferation and promote the formation of cell colonies in the microcapsules; silk fibroin can form an embedded gel-cell microcapsule complex with microencapsulated cells, which provided mechanical support for the structure of the composite. We hope that this bottom-up construction system will have potential applications in the fields of cell culture and tissue construction.

Cancer Cytomembrane-Cloaked Prussian Blue Nanoparticles Enhance the Efficacy of Mild-Temperature Photothermal Therapy by Disrupting Mitochondrial Functions of Cancer Cells.

Despite its success against cancer, photothermal therapy (PTT) (>50 °C) suffers from several limitations such as triggering inflammation and facilitating immune escape and metastasis and also damage to the surrounding normal cells. Mild-temperature PTT has been proposed to override these shortcomings. We developed a nanosystem using HepG2 cancer cell membrane-cloaked zinc glutamate-modified Prussian blue nanoparticles with triphenylphosphine-conjugated lonidamine (HmPGTL NPs). This innovative approach achieved an efficient mild-temperature PTT effect by downregulating the production of intracellular ATP. This disrupts a section of heat shock proteins that cushion cancer cells against heat. The physicochemical properties, anti-tumor efficacy, and mechanisms of HmPGTL NPs both in vitro and in vivo were investigated. Moreover, the nanoparticles cloaked with the HepG2 cell membrane substantially prolonged the circulation time in vivo. Overall, the designed nanocomposites enhance the efficacy of mild-temperature PTT by disrupting the production of ATP in cancer cells. Thus, we anticipate that the mild-temperature PTT nanosystem will certainly present its enormous potential in various biomedical applications.

A carboxymethyl lentinan layer by layer self-assembly system as a promising drug chemotherapeutic platform.

Surface functionalization of mesoporous silica nanoparticles (MSNs) has been proposed as an efficient strategy for enhancing the biocompatibility and efficiency of an MSN-based carrier platform. Herein, natural polyelectrolyte multilayers composed of poly-l-ornithine (PLO) and carboxymethyl lentinan (LC) were coated on the surface of MSNs through a layer-by-layer (LbL) self-assembly technique, and were characterized by ζ-potential, FTIR, 13C NMR, SEM, TEM, XRD, and TG. The prepared carrier presented alternating positive and negative potentials when coated with the polyelectrolytes, and the surface of MSN-PLO/LC was rougher compared to the naked MSNs. The biocompatibility tests, including cytocompatibility, hemocompatibility, and histocompatibility, showed that MSNs biocompatibility could be improved by modifying LC. A high loading and sustained release drug delivery system was constructed after loading doxorubicin (DOX) into the prepared MSN-PLO/LC, which exhibited significant anti-proliferative efficiency in human cervical cancer cell lines (Hela). Therefore, the PLO/LC LbL NPs (layer-by-layer self-assembled nanoparticles coated with PLO/LC layers) based on MSNs, which is easily prepared by electrostatic interactions, can be considered a promising drug chemotherapeutic platform and delivery technique for future human cervical cancer therapy.

Oral delivery of insulin with intelligent glucose-responsive switch for blood glucose regulation.

BACKGROUND: The traditional treatment for diabetes usually requires frequent insulin injections to maintain normoglycemia, which is painful and difficult to achieve blood glucose control. RESULTS: To solve these problems, a non-invasive and painless oral delivery nanoparticle system with bioadhesive ability was developed by amphipathic 2-nitroimidazole-L-cysteine-alginate (NI-CYS-ALG) conjugates. Moreover, in order to enhance blood glucose regulation, an intelligent glucose-responsive switch in this nanoparticle system was achieved by loading with insulin and glucose oxidase (GOx) which could supply a stimulus-sensitive turnover strategy. In vitro tests illustrated that the insulin release behavior was switched "ON" in response to hyperglycemic state by GOx catalysis and "OFF" by normal glucose levels. Moreover, in vivo tests on type I diabetic rats, this system displayed a significant hypoglycemic effect, avoiding hyperglycemia and maintaining a normal range for up to 14 h after oral administration. CONCLUSION: The stimulus-sensitive turnover strategy with bioadhesive oral delivery mode indicates a potential for the development of synthetic GR-NPs for diabetes therapy, which may provide a rational design of proteins, low molecular drugs, as well as nucleic acids, for intelligent releasing via the oral route.

Bioinspired red blood cell membrane-encapsulated biomimetic nanoconstructs for synergistic and efficacious chemo-photothermal therapy.

Recently, the fabrication of nanotechnology-based co-delivery systems has garnered enormous interest for efficacious cancer therapy. However, these systems still face certain challenges such as codelivery of drugs with different chemistries, inadequate loading efficiency, immune rejection resulting in rapid clearance and substantially poor bioavailability in vivo. To address the challenges, we have developed a biomimetic and stable design based on bovine serum albumin (BSA) nanoparticles that are encapsulated with a hydrophilic photothermal agent, indocyanine green (ICG), as well as a hydrophobic agent, gambogic acid (GA), via the desolvation method. Furthermore, these nanoconstructs have been coated with the red blood cell membranes (RBCm), which exhibit pronounced long-term circulation in addition to avoiding premature leakage of drugs. RBCm-coated BSA nanoparticles show a higher affinity towards both GA and ICG (RmGIB NPs), resulting in high loading efficiencies of 24.3 ±â€¯1.2 % and 25.0 ±â€¯1.2 %, respectively. Moreover, the bio-efficacy investigations of these biomimetic constructs (RmGIB NPs) in cells in vitro as well as in tumor-bearing mice in vivo confirm augmented inhibition, demonstrating potential synergistic chemo-photothermal therapeutic efficacy. Altogether, we provide an efficient delivery platform for designing and constructing BSA nanovehicles toward synergistic and effective co-delivery of therapeutics.

Bioactive nanoparticle embedded microcapsules for improving the efficacy of type I diabetes therapy.

In order to overcome the side effects of pancreatic transplantation and insulin injection treatment for type I diabetes, we established a drug delivery system employing nanoparticle embedded microcapsules (NEMs). The system co-encapsulated chitosan nanoparticles with γ-aminobutyric acid and ß-TC-6 cells for combined drug and cell therapy in diabetes mellitus (DM). The NEMs, which were formed via high-voltage electrostatic method, had an excellent sphericity with a smooth surface. The average size NEM was 245.52 ± 22.00 µm, which indicated a good size for cell encapsulation. Haemolysis rate of NEMs at concentrations of 100, 200 or 300 mg/mL were all below 5%. Relative viability rates of L929 cells with the same concentrations at 24, 48 or 72 h were all above 80%. We implanted bioactive NEMs into type 1 DM mice to evaluate the effect of the combined therapy. The level of blood glucose in the group receiving the combined therapy decreased during the first 2 weeks of treatment. During the next week, the level of blood glucose stayed in a safe range. Body weight continuously increased during the postoperative period after combined therapy group. Oral glucose tolerance test (OGTT) performed after 24 d showed that the level of blood glucose combined therapy reached the maximum peak of 13.04 mmol/L, lower than 16.56 mmol/L for the cell therapy group. This primary study indicated that microencapsulation technology and combined therapy are promising for the treatment of type I diabetes mellitus.

The Influence of bFGF on the Fabrication of Microencapsulated Cartilage Cells under Different Shaking Modes.

Cell encapsulation in hydrogels has been extensively used in cytotherapy, regenerative medicine, 3D cell culture, and tissue engineering. Herein, we fabricated microencapsulated cells through microcapsules loaded with C5.18 chondrocytes alginate/chitosan prepared by a high-voltage electrostatic method. Under optimized conditions, microencapsulated cells presented uniform size distribution, good sphericity, and a smooth surface with different cell densities. The particle size distribution was determined at 150⁻280 µm, with an average particle diameter of 220 µm. The microencapsulated cells were cultured under static, shaking, and 3D micro-gravity conditions with or without bFGF (basic fibroblast growth factor) treatment. The quantified detection (cell proliferation detection and glycosaminoglycan (GAG)/type II collagen (Col-II)) content was respectively determined by cell counting kit-8 assay (CCK-8) and dimethylmethylene blue (DMB)/Col-II secretion determination) and qualitative detection (acridine orange/ethidium bromide, hematoxylin-eosin, alcian blue, safranin-O, and immunohistochemistry staining) of these microencapsulated cells were evaluated. Results showed that microencapsulated C5.18 cells under three-dimensional microgravity conditions promoted cells to form large cell aggregates within 20 days by using bFGF, which provided the possibility for cartilage tissue constructs in vitro. It could be found from the cell viability (cell proliferation) and synthesis (content of GAG and Col-II) results that microencapsulated cells had a better cell proliferation under 3D micro-gravity conditions using bFGF than under 2D conditions (including static and shaking conditions). We anticipate that these results will be a benefit for the design and construction of cartilage regeneration in future tissue engineering applications.

Poly-allylamine hydrochloride and fucoidan-based self-assembled polyelectrolyte complex nanoparticles for cancer therapeutics.

Herein, we fabricated the novel drug delivery system based on the self-assembly of two polyelectrolytes, poly-allylamine hydrochloride (PAH) and fucoidan, as the polycation and polyanion, respectively, under mild conditions for cancer therapeutics. Furthermore, the designed polyelectrolyte complex nanoparticles as well as the methotrexate (MTX) disodium salt-loaded composites were systematically characterized using various techniques. The MTX loading in the nanoparticles was confirmed by zeta potential values that changed from -36.2 ± 2.2 to -28.3 ± 3.1 mV at a loading amount of 13.3 ± 1.2%. Furthermore, the obtained eventual particle sizes of nanoparticles were various with different concentrations and ratios of polyelectrolytes. The particle size also has increased from 130 ± 2.6 to 162.9 ± 2.3 nm after loading MTX. The drug release investigations in vitro at a pH value of 6.0 (acid environment) showed that the release of MTX was sustained in the conditions provided. Finally, we investigated the anticancer efficacy of MTX-loaded nanoparticles on MCF-7 cells and HeLa cells and the satisfactory results were obtained. Together, these self-assembled PAH/fucoidan nanoparticles with sustained drug release property will become the promising delivery system for cancer therapeutics. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 339-347, 2019.

Bacterial magnetosomes-based nanocarriers for co-delivery of cancer therapeutics in vitro.

In recent times, co-delivery of therapeutics has emerged as a promising strategy for treating dreadful diseases such as cancer. MATERIALS AND METHODS: In this study, we developed a novel nanocarrier based on bacterial magnetosomes (BMs) that co-loaded with siRNA and doxorubicin (DOX) using polyethyleneimine (PEI) as a cross-linker (BMs/DP/siRNA). The delivery efficiency of siRNA as well as the pH-responsive release of DOX, and synergistic efficacy of these therapeutics in vitro were systematically investigated. RESULTS: The structure of DOX-PEI (DP) conjugates that synthesized via hydrazone bond formation was confirmed by 1H nuclear magnetic resonance (NMR). The in vitro release experiments showed that the DP conjugate (DOX-loading efficiency - 5.77%±0.08%) exhibited the long-term release behavior. Furthermore, the optimal BMs/DP/siRNA particle size of 107.2 nm and the zeta potential value of 31.1±1.0 mV facilitated enhanced cellular internalization efficiency. Moreover, the agarose gel electrophoresis showed that the co-delivery system could protect siRNA from degradation in serum and RNase A. In addition, the cytotoxicity assay showed that BMs/DP/siRNA could achieve an excellent synergistic effect compared to that of siRNA delivery alone. The acridine orange (AO)/ethidium bromide (EB) double staining assay also showed that BMs/DP/siRNA complex could induce cells in a stage of late apoptosis and nanocomplex located in the proximity of the nucleus. CONCLUSION: The combination of gene and chemotherapeutic drug using BMs is highly efficient, and the BMs/DP/siRNA would be a promising therapeutic strategy for the future therapeutics.

Primary biocompatibility tests of poly(lactide-co-glycolide)-(poly-L-orithine/fucoidan) core-shell nanocarriers.

Layer-by-layer (LbL) self-assembly is the technology used in intermolecular static electricity, hydrogen bonds, covalent bonds and other polymer interactions during film assembling. This technology has been widely studied in the drug carrier field. Given their use in drug delivery systems, the biocompatibility of these potential compounds should be addressed. In this work, the primary biocompatibility of poly(lactide-co-glycolide)-(poly-L-orithine/fucoidan) [PLGA-(PLO/fucoidan)] core-shell nanoparticles (NPs) was investigated. Atomic force microscopy revealed the PLGA-(PLO/Fucoidan)4 NPs to be spherical, with a uniform size distribution and a smooth surface, and the NPs were stable in physiological saline. The residual amount of methylene chloride was further determined by headspace gas chromatography, in which the organic solvent can be volatilized during preparation. Furthermore, cell viability, acridine orange/ethidium bromide staining, haemolysis and mouse systemic toxicity were all assessed to show that PLGA-(PLO/fucoidan)4 NPs were biocompatible with cells and mice. Therefore, these NPs are expected to have potential applications in future drug delivery systems.

Effect of γ-Aminobutyric Acid-Chitosan Nanoparticles on Glucose Homeostasis in Mice.

Diabetes mellitus is the most common endocrine disease worldwide; hyperglycemia is a hallmark of this disease. To alleviate the pain caused by diabetes, developing and utilizing effective diabetic drugs to maintain or recover the function of the residual ß-cells is an attractive therapeutic approach. γ-aminobutyric acid (GABA) has been shown to have such effects, but it is easy to have reduced GABA activity under physiological conditions. In the present study, GABA-chitosan nanoparticles (GABA-CS NPs) were prepared, and glucose homeostasis, pancreatic ß-cell protection, and anti-inflammatory effects of GABA-CS NPs were investigated in vivo. The results showed that blood glucose levels and IL-1ß levels in the GABA-CS NP-administered group were both significantly lower, whereas the PDX1 expression was significantly higher than that of the impaired group (p < 0.01). This indicates that GABA-CS NPs can efficiently maintain glucose homeostasis, protect ß-cells, and inhibit inflammation. These nanoparticles have the potential to be applied for future diabetes theranostics.

Poly-L-ornithine/fucoidan-coated calcium carbonate microparticles by layer-by-layer self-assembly technique for cancer theranostics.

Recently, the layer-by-layer (LbL) self-assembly technology has attracted the enormous interest of researchers in synthesizing various pharmaceutical dosage forms. Herewith, we designed a biocompatible drug delivery system containing the calcium carbonate microparticles (CaCO3 MPs) that coated with the alternatively charged polyelectrolytes, i.e., poly-L-ornithine (PLO)/fucoidan by LbL self-assembly process (LbL MPs). Upon coating with the polyelectrolytes, the mean particle size of MPs obtained from SEM observations increased from 1.91 to 2.03 µm, and the surface of LbL MPs was smoothened compared to naked CaCO3 MPs. In addition, the reversible zeta potential changes have confirmed the accomplishment of layer upon a layer assembly. To evaluate the efficiency of cancer therapeutics, we loaded doxorubicin (Dox) in the LbL MPs, which resulted in high (69.7%) drug encapsulation efficiency. The controlled release of Dox resulted in the significant antiproliferative efficiency in breast cancer cell line (MCF-7 cells), demonstrating the potential of applying this innovative drug delivery system in the biomedical field.

The influence of spatial distribution on add-on therapy of designed Ca-Alg/CS MEMs system.

To improve the efficacy and reduce the systemic toxicity of the diabetes mellitus, herewith, we developed a novel microparticles-embedded microcapsules (MEMs) system, synthesized from calcium alginate/chitosan (Ca-Alg/CS), by emulsion gelation using a high voltage electrostatic droplet generator. In our study, we selected two antidiabetic drugs insulin (INS) and metformin (MET) as model drugs to investigate different spatial distribution appropriate of MEMs system. Characterization based on particle size and morphology, encapsulation efficiency and drug loading, as well as drug delivery properties were carried out on the MEMs system. Typical multi-chamber structure was shown by SEM and the optical spectra. The average diameters of microparticles and Ca-Alg/CS MEMs were 2100 nm and 410 µm, respectively. Insulin and MET were embedded into MEMs via electrostatic reaction according to FT-IR spectra. Moreover, drug loading and encapsulation efficiency of INS were higher than that of MET in this system when drugs were loaded alone or together. More importantly, this system has potential for orderly drug release and well sustained release when MET in the inner and INS in the outer space could be applied as a combination therapy for diabetes. The obtained in vivo experimental data on diabetes rats has shown that the designed MEMs system resulted in a higher hypoglycemic effect within add-on therapy.

Bacterial magnetosomes as an efficient gene delivery platform for cancer theranostics.

BACKGROUND: Gene therapy has gained an increasing interest in its anti-tumor efficiency. However, numerous efforts are required to promote them to clinics. In this study, a novel and efficient delivery platform based on bacterial magnetosomes (BMs) were developed, and the efficiency of BMs in delivering small interfering ribonucleic acid (siRNA) as well as antiproliferative effects in vitro were investigated. RESULTS: Initially, we optimized the nitrogen/phosphate ratio and the BMs/siRNA mass ratio as 20 and 1:2, respectively, to prepare the BMs-PEI-siRNA composites. Furthermore, the prepared nanoconjugates were systematically characterized. The dynamic light scattering measurements indicated that the particle size and the zeta potential of BMs-PEI-siRNA are 196.5 nm and 49.5 ± 3.77 mV, respectively, which are optimum for cell internalization. Moreover, the confocal laser scanning microscope observations showed that these composites were at a proximity to the nucleus and led to an effective silencing effect. BMs-PEI-siRNA composites efficiently inhibited the growth of HeLa cells in a dose-as well as time-dependent manner. Eventually, a dual stain assay using acridine orange/ethidium bromide, revealed that these nanocomposites induced late apoptosis in cancer cells. CONCLUSIONS: A novel and efficient gene delivery system based on BMs was successfully produced for cancer therapy, and these innovative carriers will potentially find widespread applications in the pharmaceutical field.

Co-microencapsulation of BMSCs and mouse pancreatic ß cells for improving the efficacy of type I diabetes therapy.

INTRODUCTION: To overcome the shortcomings of pancreas transplantation and insulin injection treatment for type I diabetes, biocompatible materials were used to prepare alginate-chitosan-alginate microcapsules that co-encapsulated bone marrow mesenchymal stem cells and mouse pancreatic ß cells to treat diabetic mice. METHODS: Blank alginate-chitosan-alginate (ACA) microcapsules and co-microencapsulated cells were prepared using a high-voltage electrostatic method and then characterized using an inverted microscope. Cell viability was evaluated using AO/EB staining. ELISA kit was used to detect insulin secretion. Peri-orbital blood samples were obtained from the mice for blood glucose determination every week for one month. RESULTS: After 28 days of in vitro culture, the secretion of insulin following co-microencapsulation was higher than that observed for microencapsulated beta-TC-6 cells alone. On the 28th day after transplantation, the blood glucose level was 6.86 mmol/L in the microencapsulated beta-TC-6 group. On the 14th day, the blood glucose level was 6.80 mmol/L in the co-microencapsulated BMSC/beta-TC-6 group, which was close to the normal blood glucose level of healthy mice. These results indicated that the efficacy in reducing blood glucose was better in the co-microencapsulated BMSC/beta-TC-6 group. CONCLUSIONS: This primary study indicated that combining microencapsulation technology and co-culture of stem cells and somatic cells shows promise for the treatment of type I diabetes mellitus.

A Natural Bacterium-Produced Membrane-Bound Nanocarrier for Drug Combination Therapy.

To minimize the non-specific toxicity of drug combination during cancer therapy, we prepared a new system synthesized from bacteria to deliver the anticancer drugs cytosine arabinoside (Ara-C) and daunorubicin (DNR). In this study, we selected genipin (GP) and poly-l-glutamic acid (PLGA) as dual crosslinkers. Herewith, we demonstrated the preparation, characterization and in vitro antitumor effects of Ara-C and DNR loaded GP-PLGA-modified bacterial magnetosomes (BMs) (ADBMs-P). The results show that this new system is stable and exhibits optimal drug-loading properties. The average diameters of BMs and ADBMs-P were 42.0 ± 8.6 nm and 65.5 ± 8.9 nm, respectively, and the zeta potential of ADBMs-P (-42.0 ± 6.4 mV) was significantly less than that of BMs (-28.6 ± 7.6 mV). The optimal encapsulation efficiency and drug loading of Ara-C were 68.4% ± 9.4% and 32.4% ± 2.9%, respectively, and those of DNR were 36.1% ± 2.5% and 17.9% ± 1.6%. Interestingly, this system also exhibits long-term release behaviour sequentially, without an initial burst release. The Ara-C drug continued to release about 85% within 40 days, while DNR release lasted only for 13 days. Moreover, similar to free drugs, ADBMs-Ps are strongly cytotoxic to cancer cells in vitro (HL-60 cells), with the inhibition rate approximately 96%. This study reveals that this new system has a potential for drug delivery application in the future, especially for combination therapy.

Preparation of ALG-g-Lys and its application as a novel drug carrier.

In order to improve alginate microbead stability and further broaden the application of alginate in biomaterials, a new biomaterial, ALG-g-Lys, was prepared and its possibility as a novel drug carrier investigated. The carrier exhibited a sustained release property and preserved activity with no initial burst release, and interestingly, GP-crosslinked ALG-g-Lys microspheres showed obvious fluorescence properties, which showed promising potential for the future drug delivery systems.