Folic acid-conjugated pH-responsive poly(methacrylic acid) nanospheres for targeted delivery of anticancer drugs to breast cancer cells

Synthesis and characterization of folate functionalized core-shell pluronic/chitosan nanoparticles against rheumatoid arthritis

Significant advances in novel drug delivery systems have led to the development of ligand-conjugated nanoparticles, enabling targeted delivery of therapeutic agents to disease-specific sites. A widely adopted approach for treating rheumatoid arthritis involves targeting folate receptors, which are overexpressed in inflamed tissues. This study focused on formulating methotrexate-loaded, folate-conjugated core-shell polymeric nanoparticles (PF/CS). These nanoparticles were synthesized using self-micellization and ionic gelation techniques, resulting in particles with an average size of 185.0 ± 2.08 nm, a PDI of <0.5, and a zeta potential of 19.9 ± 2.23 mV indicating excellent stability and uniformity. Ligand conjugation was confirmed using 1H Nuclear Magnetic Resonance Spectroscopy and Fourier Transformed Infrared Spectroscopy. Further physicochemical characterization, including Differential Scanning Calorimetry, Thermo-Gravimetric Analysis, and X-ray Diffraction analysis, demonstrated good compatibility and thermal stability. In vitro studies showed sustained drug release for up to 72 h and higher cytotoxicity against RAW 264.7 macrophage cells with folate-conjugated PF/CS nanoparticles compared to non-conjugated ones. Ex-vivo hemocompatibility testing confirmed their non-hemolytic nature. Acute toxicity studies indicated biocompatibility and safety. In vivo assessments in rats showed enhanced therapeutic effects with folate-conjugated nanoparticles. In silico modeling supported experimental findings. It is concluded that folate-conjugated PF/CS nanoparticles offer a promising platform for sustained methotrexate delivery in rheumatoid arthritis treatment.

A poly (vinyl alcohol) coated core-shell nanoparticle with a tunable surface for pH and glutathione dual-responsive drug delivery

The surface characteristics of nanoparticles play a pivotal role in modulating the efficiency and functionality of drug delivery systems, particularly when addressing the complex challenges of targeted therapeutics. This study presents the development of a core-shell nanoparticle system (PMAA@DOX-PVA), incorporating poly(vinyl alcohol) (PVA) as a dynamic shell component to establish dual responsiveness to pH and glutathione levels. The hydrophilic PVA shell is covalently conjugated to the poly (methylacrylic acid) (PMAA) core via a boronic ester bond, establishing a robust platform for controlled release with tunable surface properties. Notably, our findings demonstrate a remarkable enhancement in drug loading efficiency from a modest 8 % (PMAA@DOX) to an impressive 18 % (PMAA@DOX-PVA-0.2). Furthermore, under physiological conditions (pH 7.4), the drug leakage after 62 hours is significantly reduced, dropping from 37 % (PMAA@DOX) to 21 % (PMAA@DOX-PVA-0.2). This suggests a potential improvement in stability during blood circulation. Intriguingly, the PVA ratio was found to influence drug release profiles under different environments distinctly. The possible mechanism was proposed offering insight into this tunable behavior. In vitro cytotoxicity assays on A549 cancer cells reveal that the blank carriers exhibit excellent biocompatibility, while the PVA-coated nanoparticles significantly boost anti-tumor efficacy. Collectively, these results present a promising strategy for designing core-shell nanoparticles with customizable surface properties, paving the way for next-generation, multifunctional drug delivery systems in diverse biomedical applications.

Advanced Bioresponsive Drug Delivery Systems for Promoting Diabetic Vascularized Bone Regeneration

The treatment of bone defects in diabetes mellitus (DM) patients remains a major challenge since the diabetic microenvironments significantly impede bone regeneration. Many abnormal factors including hyperglycemia, elevated oxidative stress, increased inflammation, imbalanced osteoimmune, and impaired vascular system in the diabetic microenvironment will result in a high rate of impaired, delayed, or even nonhealing events of bone tissue. Stimuli-responsive biomaterials that can respond to endogenous biochemical signals have emerged as effective therapeutic systems to treat diabetic bone defects via the combination of microenvironmental regulation and enhanced osteogenic capacity. Following the natural bone healing processes, coupling of angiogenesis and osteogenesis by advanced bioresponsive drug delivery systems has proved to be of significant approach for promoting bone repair in DM. In this Review, we have systematically summarized the mechanisms and therapeutic strategies of DM-induced impaired bone healing, outlined the bioresponsive design for drug delivery systems, and highlighted the vascularization strategies for promoting bone regeneration. Accordingly, we then overview the recent advances in developing bioresponsive drug delivery systems to facilitate diabetic vascularized bone regeneration by remodeling the microenvironment and modulating multiple regenerative cues. Furthermore, we discuss the development of adaptable drug delivery systems with unique features for guiding DM-associated bone regeneration in the future.

Synthesis of quercetin-loaded hyaluronic acid-conjugated pH/redox dual-stimuli responsive poly(methacrylic acid)/mesoporous organosilica nanoparticles for breast cancer targeted therapy

In the current study, a combination of precipitation polymerization and modified sol-gel methods were developed to prepare the novel hyaluronic acid-decorated pH and redox dual-stimuli responsive poly(methacrylic acid)/mesoporous organosilica nanoparticles with a core-shell structure for controlled drug release. The nanocarriers have a proper particle size of <200 nm, high negative zeta potential greater than -30 mV, controllable diameter, and tunable shell thickness. The prepared nanoparticles were able to entrap over 70 % of quercetin with a drug loading of >10 %, due to the mesoporous shell. In vitro drug release profiles indicated that the systems had good stability under normal physiological media, while the cumulative release was significantly accelerated at the simulated tumor tissue condition, which shows pH and redox-dependent drug release. In vitro cell viability and apoptosis assay proved that the obtained nanomaterials possess relatively good biocompatibility, and drug-loaded targeted nanoparticles exhibited greater cytotoxicity on MCF-7 human breast cancer cells than free drug and non-targeted nanocarriers due to the enhanced cellular uptake of nanoparticles via CD44 receptors overexpressed. All these findings demonstrated that proposed nanocarriers might be promising as a smart drug delivery system to improve the antitumor efficacy of chemotherapeutic drugs.

Impedimetric Detection of Cancer Markers Based on Nanofiber Copolymers

The sensitive determination of folate receptors (FRs) in the early stages of cancer is of great significance for controlling the progression of cancerous cells. Many folic acid (FA)-based electrochemical biosensors have been utilized to detect FRs with promising performances, but most were complicated, non-reproducible, non-biocompatible, and time and cost consuming. Here, we developed an environmentally friendly and sensitive biosensor for FR detection. We proposed an electrochemical impedimetric biosensor formed by nanofibers (NFs) of bio-copolymers prepared by electrospinning. The biosensor combines the advantages of bio-friendly polymers, such as sodium alginate (SA) and polyethylene oxide (PEO) as an antifouling polymer, with FA as a biorecognition element. The NF nanocomposites were characterized using various techniques, including SEM, FTIR, zeta potential (ZP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). We evaluated the performance of the NF biosensor using EIS and demonstrated FR detection in plasma with a limit of detection of 3 pM. Furthermore, the biosensor showed high selectivity, reliability, and good stability when stored for two months. This biosensor was constructed from 'green credentials' holding polymers that are highly needed in the new paradigm shift in the medical industry.

Folic Acid-Decorated Chitosan-PLGA Nanobiopolymers for Targeted Drug Delivery to Acute Lymphoblastic Leukemia Cells: In Vitro Studies

OBJECTIVES

This study developed a drug delivery system (DDS) using folic acid (FA)-functionalized chitosan (CS) and poly (lactic-co-glycolic acid) (PLGA) nanocarriers for targeted sodium butyrate (NB) delivery to leukemia cells (NALM6). The goal was to enhance NB's therapeutic efficacy while reducing its cytotoxicity to non-malignant cells.

METHODS

FA-CS-PLGA nanocarriers were synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Encapsulation efficiency, release kinetics, cytotoxicity, and apoptosis induction were assessed using MTT assays and flow cytometry in NALM6 cells.

RESULTS

The FA-CS-PLGA nanocarriers had a surface charge of 34.2 ± 0.12 mV and a size range of 40-60 nm. Encapsulation efficiency was 16%, with 16% of NB released within the first 4 h. MTT assays showed a reduction in leukemia cell viability to 26% after 24 h with 400 nM FA-CS-PLGA-NB, compared to over 50% viability with pure NB. The IC50 was around 300 nM. Flow cytometry revealed that FA-CS-PLGA-NB induced apoptosis in over 20% of leukemia cells, far exceeding the 5% induced by unmodified NB.

CONCLUSION

FA-CS-PLGA nanocarriers show significant promise as a targeted DDS for leukemia therapy, enhancing NB delivery to leukemia cells and improving therapeutic efficacy while minimizing off-target toxicity. These results support further in vivo studies and potential clinical applications.

Temperature and pH-responsive PNIPAM@PAA Nanospheres with a Core-Shell Structure for Controlled Release of Doxorubicin in Breast Cancer Treatment

Stimuli-responsive polymers have been of great interest in the fabrication of advanced drug delivery systems. In this study, a facile approach was developed to synthesize a dually temperature/pH-responsive drug delivery system with a core-shell structure to control the release of doxorubicin (DOX) at the target site. For this purpose, poly(acrylic acid) (PAA) nanospheres were first synthesized using the precipitation polymerization technique and were used as pH-responsive polymeric cores. Then, poly(N-isopropylacrylamide) (PNIPAM) with thermo-responsivity properties was coated on the outer surface of PAA cores via seed emulsion polymerization technique to render monodisperse PNIPAM-coated PAA (PNIPAM@PAA) nanospheres. The optimized PNIPAM@PAA nanospheres with an average particle size of 116.8 nm (PDI= 0.243), had a high negative surface charge (zeta potential= -47.6 mV). Then, DOX was loaded on PNIPAM@PAA nanospheres and the entrapment efficiency (EE) and drug loading (DL) capacity were measured to be 92.7% and 18.5%, respectively. The drug-loaded nanospheres exhibited a low leakage at neutral pH and physiological temperature, but drug release significantly enhanced at acidic pH (pH= 5.5), indicating the tumor-environment responsive drug release behavior of the prepared nanospheres. Also, kinetics studies showed that, the sustained release of DOX from PNIPAM@PAA nanospheres was consistent with the Fickian diffusion mechanism. Moreover, the anticancer efficacy of DOX-loaded nanospheres was evaluated in vitro against MCF-7 breast cancer cells. The obtained results revealed that, the incorporation of DOX into PNIPAM@PAA nanospheres increases its cytotoxicity against cancer cells compared to the free DOX. Our results suggest that, PNIPAM@PAA nanospheres can be considered as a promising vector to release anticancer drugs with dual-stimuli responsivity to pH and temperature.

Distinguishing the Cellular Transport of Folic Acid Conjugated Nano-Drugs among Different Cell Lines by Using Force Tracing Technique

Folic acid (FA) is a ligand that has been renowned for its strong binding to FA receptor (FR), and the robustness of the specific interaction has led to the generation of multitudinous tumor-targeted nano-drug delivery systems. However, selecting the appropriate FA targeted nano-drugs according to types of cancerous cells to achieve a high effect is critical. Understanding of how the drug is transported through the cell membrane and is delivered intracellularly is very important in screening ideal targeted nano-drugs for cancerous changes in different organs. Herein, by using a force tracing technique based on atomic force microscopy (AFM), the dynamic process of FA-polyamidoamine-Doxorubicin (FA-PAMAM-DOX) entry into different tumor cells (HeLa and A549) and normal cells (Vero) was monitored in real time. The cell membrane transport efficacy of FA-PAMAM-DOX in tumor cells with an FR high overexpression level (HeLa) and FR low overexpression level (A549) is analyzed, which is significantly higher than that in normal cells (Vero), especially for HeLa cells. Subsequently, the intracellular delivery efficiency of FA-PAMAM-DOX in different cell lines was measured by using fluorescence imaging and AFM-based nanoindentation techniques. This report will help to discover the cellular transport mechanism of nano-drugs and screen out optimal therapeutic nano-drugs for different types of tumors.

Chemiluminescent Nanogels as Intensive and Stable Signal Probes for Fast Immunoassay of SARS-CoV-2 Nucleocapsid Protein

It is highly desired to exploit good nanomaterials as nanocarriers for immobilizing chemiluminescence (CL) reagents, catalysts and antibodies to develop signal probes with intensive and stable CL properties for immunoassays. In this work, N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and Co2+ bifunctionalized polymethylacrylic acid nanogels (PMAANGs-ABEI/Co2+) were synthesized via a facile strategy by utilizing carboxyl group-rich PMAANGs as nanocarriers to immobilize ABEI and Co2+. The obtained PMAANGs-ABEI/Co2+ showed extraordinary CL performance. The CL intensity is 2 orders of magnitude higher than that of previously reported ABEI and Cu2+-cysteine complex bifunctionalized gold nanoparticles with high CL efficiency. This was attributed to the excellent catalytic ability of Co2+ and polymethylacrylic acid nanogels, as well as the improved CL catalytic efficiency from a decreased spatial distance between ABEI and the catalyst. The as-prepared nanogels also possess abundant surface reaction sites and good CL stability. On this basis, a sandwich immunoassay for the nucleocapsid protein of SARS-CoV-2 (N protein) was developed by using magnetic bead connected primary antibody as a capture probe and PMAANGs-ABEI/Co2+ connected secondary antibody as a signal probe. The linear range of the proposed method for N protein detection was 3.16-316 ng/mL, and its detection limit was 2.19 ng/mL (S/N = 3). Moreover, the developed immunoassay was performed with a short incubation time of 5 min, which greatly reduced the detection time for N protein. By using corresponding antibodies, the developed strategy might be applied to detect other biomarkers.